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Microbiology Flashcards

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Biology 101 flashcards
1
Q

G+
A normal inhabitant of the oral cavity, infection can be associated with dental procedures, with formation of lesions that erupt through the face with a purulent discharge

A 
Actinomycetes israelii
(diagnosis is by finding sulfur granules = tangles of filaments of organisms wrapped in a matrix of calcium phosphate, imparting a yellow [sulfur] color to the abscess and discharge)
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2
Q

G+
The most severe form of this disease results from the inhalation of spores with mediastinitis, pulmonary edema, and hemorrhage (Woolsorter’s disease)

A

Bacillus anthracis
(can occur as an occupational disease of textile or agricultural personnel resulting from contact with infected hides or wool; recently, it has gained attention as an agent of biowarfare and bioterrorism)

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3
Q

G+

Causes gastroenteritis and is typically associated with the consumption of reheated rice

A

Bacillus cereus
(rapid emesis or diarrhea is associated with an enterotoxin that increased cAMP and is produced by the organism as it germinates)

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4
Q

G+
Disease can be due to the ingestion of preformed toxin in home-canned foods or by the ingestion of spores in honey by an infant

A

Clostridium botulinum

symptoms include flaccid paralysis, dry mouth, diplopia, dysphagia, and respiratory failure

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5
Q

G+

Associated with the use of broad-spectrum antibiotics and the overgrowth of toxin-producing bacteria

A 
Clostridium difficile
(results in pseudomembranous colitis and is also a major nosocomial disease)
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6
Q

G+

Causes gas gangrene and is often associated with automobile and motorcycle accidents

A

Clostridium perfringens
(spores are abundant in soil and germinate in wounds; treatment includes surgical debridement, antibiotics, and hyperbaric oxygen)

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7
Q

G+
Infection is associated with traumatic inoculation of spores that germinate and produce a toxin that causes a spastic paralysis

A 
Clostridium tetani
(the organism looks like a long rod with a dilated terminal end containing a spore that resembles a tennis racquet)
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8
Q

G+

Can cause risus sardonicus, the characteristics grimace of lockjaw

A

Clostridium tetani
(treatment includes the use of antitoxins produced in horses or hyperimmunized humans, and antispasmodics such as benzodiazepines)

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9
Q

G+

Causes gray pseudomembranes on the back of the throat

A

Corynebacterium diphtheriae

organism often viewed in a “Chinese-letter” configuration

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10
Q

G+

A common cause of nosocomial infections, this organism is often resistant to many antibiotics, including vancomycin

A

Enterococcus spp.

common cause of urinary tract infections, sepsis, meningitis, and endocarditis

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11
Q

G+

Causes a fishy smelling vaginal discharge

A 
Gardnerella vaginalis
(histologically characterized by the presence of "clue cells", vaginal epithelial cells covered with bacteria, see on a Pap smear)
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12
Q

G+

As the dominant organism of normal vaginal flora, its metabolism helps maintain the low pH of the vagina

A

Lactobacillus spp.
(the lactic acid produced helps prevent the overgrowth of potentially pathogenic organisms; with the use of broad-spectrum antibiotics, such acid-producing flora is lost, allowing for overgrowth of pathogenic species)

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13
Q

G+
This cause of late onset neonatal sepsis is a facultative intracellular parasite that spreads from cell to cell via actin rockets

A 
Listeria monocytogenes
(this organism can be detected as short non-spore-forming rods with a tumbling end-over-end motility)
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14
Q

G+
As well as being gram positive, this organism is also weakly acid fast and causes a pneumonia predominantly in immuno-compromised patients

A

Nocardia asteroides

this aerobic bacteria with filamentous growth is a common soil organism

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15
Q

G+

Part of the microbial flora of the skin, this bacilli contributes to the development of acne

A 
Propionibacterium acnes
(the organism produces lipases that split fatty acids that cause inflammation, resulting in the formation of comedones)
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16
Q

G+

A major cause of acute bacterial endocarditis, especially in IV drug users

A 
Staphylococcus aureus
(unlike subacute bacterial endocarditis, this organism can cause infection of undamaged heart valves, typically on the right side [tricuspid] in IV drug users)
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17
Q

G+

A major cause of abscesses, furuncles, carbuncles, and other skin infections such as impetigo

A

Staphylococcus aureus

this beta-hemolytic cocci grows in grape-like clusters, produces coagulase, and grows in culture as yellowish colonies

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18
Q

G+
Part of the normal flora of the skin, it causes infection of IV lines and catheters; it is a major cause of endocarditis in patients with prosthetic heart valves

A 
Staphylococcus epidermidis
(similar to Staphylococcus aureus, but grows as white colonies, does NOT produce coagulase, does NOT ferment mannitol, and does NOT produce Protein A)
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19
Q

G+

The second leading cause of urinary tract infection in sexually active women

A

Staphylococcus saprophyticus

differentiated from Staphylococcus epidermidis by its ability to ferment mannitol and its resistance to novobiocin

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20
Q

G+

An important cause of neonatal sepsis and meningitis

A 
Streptococcus agalactiae (Group B)
(this beta-hemolytic, bacitracin-resistant cocci is a normal inhabitant of the female genital tract and can be acquired during vaginal delivery)
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21
Q

G+

A major cause of dental caries

A

Streptococcus mutans

a member of the viridans group, it is also alpha-hemolytic and optochin-resistant

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22
Q

G+

Lancet-shaped diplococci found in a rusty brown sputum

A 
Streptococcus pneumoniae
(causes >90% of all cases of lobar pneumonia)
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23
Q

G+

The use of a quellung reaction helps differentiate between the 85 different capsular subtypes

A 
Streptococcus pneumoniae
(this alpha-hemolytic, optochin-sensitive bile-soluble coccus grows on sheep red blood cell agar; the vaccine contains at least 23 of these subtypes)
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24
Q

G+

Infection results in rheumatic fever

A 
Streptococcus pyogenes (Group A)
(characterized by a constellation of symptoms including migratory polyarthritis, erythema marginatum, pancarditis, Sydenham chorea, and subcutaneous nodules)
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25
Q

G+
A major cause of pharyngitis, infection can also result in other suppurative symptoms such as erysipelas, cellulitis, and impetigo

A 
Streptococcus pyogenes (Group A)
(infection with this beta-hemolytic, bacitracin-sensitive cocci can be serodiagnosed with the detection of host antibodies to bacterial DNase B and anti-streptolysin O [ASO])
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26
Q

G+

Infection can lead to the development of acute glomerulonephritis and mitral and aortic stenosis

A 
Streptococcus pyogenes (Group A)
(immunocomplex deposition in the kidney visualized by "lumpy bumpy" immunofluorescence; cross-reactive antibodies to the bacteria result in autoimmune destruction of the heart valves)
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27
Q

G+

Leading cause of subacute bacterial endocarditis

A

Streptococcus viridans

this alpha-hemolytic, optochin-resistant cocci is part of the normal flora of the human pharynx

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28
Q

G+
Chronic exposure to this group of organisms leads to the development of hypersensitivity pneumonitis, including Farmer’s Lung, Pigeon breeder’s Lung, and Humidifier Lung

A 
Thermophilic Actinomycetes
(exposure causes an immunologically mediated interstitial fibrosis, bronchiolitis, and granuloma formation with progressive respiratory failure and cyanosis)
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29
Q

G+

The organism is detected as PAS+ rods within the macrophages of the lamina propria of the small intestine

A 
Tropheryma whippelii
(the causative agent of Whipple's disease that results in abdominal pain, malabsorption with diarrhea and weight loss, and a migratory polyarthritis)
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30
Q

G-

Predominant organism in the human colon

A

Bacteroides fragilis

most often the cause of serious anaerobic infection

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31
Q

G-
Transmitted by the bite, scratch, or lick of an infected cat, resulting in low grade fever and a characteristic enlargement of lymph nodes for several weeks

A

Bartonella henselae
(this is the causative agent of Cat scratch disease; infection of an immunocompromised patient can result in Bacillary angiomatosis, cranberry-like pustules resembling Kaposi sarcoma)

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32
Q

G-

Causes a paroxysmal cough ending with an inspiratory “whoop” as air rushed over the swollen glottis

A 
Bordetella pertussis
(the vaccine includes the purified virulence factors filamentous hemagglutinin (FHA) and pertussis toxoid, and is administered at 2, 4, 6, and 18 months along with the vaccine for Corynebacterium diphtheriae and Clostridium tetani in the DaPT vaccine)
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33
Q

G-
Transmitted by contaminated livestock and unpasteurized dairy products, infection results in a fever that rises in the morning and falls at night (Undulant fever)

A

Brucella spp.

this granulomatous infection invades the reticulo-endothelial cells of the lymph nodes, liver, spleen, and bone marrow

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34
Q

G-
Endemic to tropical nations, this sexually transmitted organism results in granulomatous genital ulcers (pseudobuboes) with the potential for autoamputation of genitalia

A 
Calymmatobacterium granulomatis
(diagnosis is based on finding intracellular organisms aggregated as "Donovani Bodies")
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35
Q

G-
A common cause of bloody diarrhea, particularly in children in close contact with puppies and kittens, which serve as reservoirs

A

Campylobacter jejuni

these rod-shaped organisms appear as “gull wing”-shaped colonies with a single flagellum

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36
Q

G-

Causes a bloody diarrhea and is associated with the consumption of undercooked meat and dairy products

A

Enterohemorrhagic Escherichia coli (E. coli O157:H7)
(this dysentery-like condition is due to the elaboration of verotoxins similar to Shiga toxin that causes cytotoxicity to the colonic mucosa)

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37
Q

G-

Infection may result in hemorrhagic colitis progressing to the hemolytic uremic syndrome (HUS)

A

Enterohemorrhagic Escherichia coli (E. coli O157:H7)

HUS is characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia in children

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38
Q

G-

Leading cause of urinary tract infections

A 
Escherichia coli
(other major causes of urinary tract infections include Proteus, Serratia, Enterococci, Klebsiella, Pseudomonas, and Staphylococcus saprophyticus)
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39
Q

G-

Causes “Traveler’s diarrhea” and is also a major cause of death in children of developing nations

A 
Escherichia coli
(the enterotoxigenic strain produces a heat stable and a heat labile toxin that causes an explosive watery diarrhea with cramping, abdominal discomfort, and dehydration)
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40
Q

G-
This zoonotic organism can be transmitted by the bite of a deerfly or tick, or through handling or consuming rabbit products, which are the reservoir

A 
Francisella tularensis
(infection can result in necrotic ulcers at the site of entry: conjunctiva (oculoglandular), mouth (typhoidal), or lungs (pneumonic tularemia) with disseminated granulomatous lesions of the lung, spleen, or liver)
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41
Q

G-

Organism closely associated with chronic gastritis and peptic ulcer disease

A

Helicobacter pylori

also associated with an increase in the development of gastric carcinoma and MALToma

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42
Q

G-

A sexually transmitted disease, results in painful necrotizing genital ulcers (Chancroid)

A 
Haemophilus ducreyi
(infection in the U.S. is rare, most infections occur in the tropics; painless ulcer = T. pallidum)
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43
Q

G-
Infection with this coccobacillus causes epiglottitis, otitis media in children, sinusitis, meningitis, and pneumonia in older patients with chronic respiratory disease

A

Haemophilus influenzae

growth in culture of this organism requires Factor V [hemin] and Factor X [NAD], found in chocolate agar media

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44
Q

G-
Formerly a leading cause of infection in children, the incidence of infection has dramatically decreased with the introduction of a vaccine

A

Haemophilus influenzae

vaccine is composed of the capsular material, polyribitol phosphate [PRP], conjugated to diphtheria toxin

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45
Q

G-

Major cause of aspiration pneumonia in alcoholics

A

Klebsiella pneumoniae
(organism produces a large antiphagocytic capsule, giving it a mucoid appearance and producing a thick, bloody, “currant-jelly” sputum)

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46
Q

G-

Paired, kidney bean-shaped diplococci within leukocytes in a urethral discharge

A

Neisseria gonorrhoeae
(differentiated from N. meningitidis based on its ability to ferment glucose and maltose, whereas N. gonorrhoeae ferments glucose only)

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47
Q

G-

Leading cause of septic arthritis

A

Neisseria gonorrhoeae

typically presents as monoarticular arthritis of the knee, ankle, or wrist after a bout of urethritis

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48
Q

G-
Infection of a neonate passing through an infected birth canal results in ophthalmia neonatorum and purulent conjunctivitis

A

Neisseria gonorrhoeae
(babies born in the U.S. receive a required administration of tetracycline, erythromycin, or silver nitrate drops to prevent this)

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49
Q

G-

Sexually transmitted disease that can lead to pelvic inflammatory disease that then predisposes to ectopic pregnancy

A

Neisseria gonorrhoeae

the second most common notifiable disease in the U.S.

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50
Q

Leading cause of meningitis among military recruits and dormitory settings

A 
Neisseria meningitidis
(patients with deficiencies in the complement components C6-9, "the membrane attack complex", are particularly susceptible to infection)
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51
Q

G-
Septicemia resulting from this organism can result in progressive hypotension, disseminated intravascular coagulation, widespread vascular purpura, and bilateral adrenal hemorrhage

A

Neisseria meningitidis
(the shock and adrenocortical insufficiency of Waterhouse-Friedrichsen Syndrome is rapidly fatal without antibiotic treatment)

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52
Q

G-
This organism is transmitted through the bite of a domestic cat or dog and can result in an abscess, cellulitis, and osteomyelitis

A 
Pasteurella multocida
(short, encapsulated, bipolar staining organism is part of the nasopharyngeal flora of domestic dogs and cats)
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53
Q

G-

Urease-positive organism that causes an alkaline urine predisposing to the formation of urinary calculi

A

Proteus spp. (P. mirabilis and P. vulgaris)
(these highly motile organisms are often refractory to antibiotic treatment because they often become trapped within stones)

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54
Q

G-

Major cause of pneumonia in burn patients and Cystic fibrosis patients

A 
Pseudomonas aeruginosa
(this obligate aerobe requires only trace elements for growth and is a major cause of nosocomial infections because it colonizes aspirators, water and ice dispensers, catheters, IV lines, and even dilute disinfectant solutions)
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55
Q

G-
Infection can result in folliculitis, swimmer’s ear, pneumonia, and sepsis with the development of characteristic skin lesions (Ecthyma gangrenosum)

A 
Pseudomonas aeruginosa
(the organism grows well in water, especially in inadequately chlorinated hot tubs; culture results in green colonies resulting from pigments pyoverdin and pyocyanin, with a characteristic fruity odor)
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56
Q

G-

Causes a self-limiting enterocolitis associated with the consumption of contaminated eggs and poultry

A 
Salmonella enteritidis
(this highly motile organism requires a large infectious dose, which distinguishes it from Shigella spp.)
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57
Q

G-

Causes an enteric fever with the development of characteristics “rose spots” on the abdomen

A

Salmonella typhi
(after recovery, a small percentage of patients may become carriers because the organisms colonize the gallbladder, a state that may require cholecystectomy)

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58
Q

G-

This organism is a common cause of nosocomial infections; some strains produce a red pigment

A 
Serratia marcescens
(causes pneumonia, bacteremia, endocarditis, and is often multidrug-resistant)
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59
Q

G-
Infection with a small dose of organisms results in dysentery that is only transmitted among humans with no animal reservoir

A 
Shigella dysenteriae
(this cause of a bloody, mucoid, low-volume diarrhea can result in life-threatening dehydration and acidosis and is often associated with insanitary conditions)
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60
Q

G-

Major cause of secretory diarrhea with life-threatening dehydration, particularly in developing nations

A 
Vibrio cholerae
(these comma-shaped rods with a polar flagellum adhere to the intestinal mucosa and elaborate an exotoxin, but never invade)
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61
Q

G-

Causes nausea, cramping, and is associated with the consumption of raw shellfish

A

Vibrio parahaemolyticus

although this free-living salt bacteria is related to Vibrio cholerae, the symptoms are much milder

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62
Q

G-

Rodents are the reservoir for this organism, transmitted by the bite of a flea, resulting in the plague

A 
Yersinia pestis
(transmission is also possible between humans in the case of pneumonic plague)
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63
Q

G-

Infection can result in pustules and enlargement of draining lymph nodes that rupture through the skin to form buboes

A

Yersinia pestis

this organism displays bipolar staining resulting in a safety pin appearance

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64
Q

Poorly staining

Late stages of infection may lead to a severe autoimmune arthritis, life-threatening heart block, and facial nerve palsy

A 
Borrelia burgdorferi
(the vaccine has recently become available for this organism, to prevent development of Lyme disease)
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65
Q

Poorly staining

Transmitted by the Ixodes tick bite that results in a characteristics bull’s eye lesion (Erythema chronicum migrans)

A 
Borrelia burgdorferi
(infection occurs mainly in the Northeast during the summer months, when the deer tick [Ixodes] is found)
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66
Q

Poorly staining

Transmitted by the human body louse, this organism causes Relapsing fever

A 
Borrelia recurrentis
(causes febrile disease that fades as antibodies develop and relapses as the organism undergoes antigenic variation of its variable major protein)
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67
Q

Poorly staining

Previously known as the TWAR agent, it is a common cause of sore throats and interstitial pneumonia

A 
Chlamydia pneumoniae
(as with all Chlamydial species, it exists as either elementary bodies, the infectious form, or as intracellular reticular bodies, the metabolically active form)
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68
Q

Poorly staining
Causes an interstitial type pneumonia and is associated with exposure to contaminated parrots and parakeets and other domestic birds

A

Chlamydia psittaci
(the causative agent of Psittacosis, transmitted by birds of the psittacine family; a similar disease, Ornithosis, is also seen upon exposure to other birds such as pigeons, ducks, and chickens)

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69
Q

Poorly staining
This cause of chronic keratoconjunctivitis results in corneal scarring and is the most common cause of blindness worldwide

A 
Chlamydia trachomatis
(Chlamydia trachomatic is divided into serovars based on serology and symptomatology; in this case, the pathology is due to C. trachomatis A, B, and C)
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70
Q

Poorly staining
This organism is the leading cause of sexually transmitted bacterial disease, resulting in urethritis, cervicitis, salpingitis, and neonatal conjunctivitis

A

Chlamydia trachomatis
(infection in a female can progress to pelvic inflammatory disease, resulting in the potential for ectopic pregnancy or sterility)

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71
Q

Poorly staining
This organism is closely associated with the development of conjunctivitis, urethritis, and arthritis (Reiter’s syndrome)

A 
Chlamydia trachomatis
(this autoimmune phenomenon resulting from cross-reactive antigens between the organism and affected tissues is associated with HLA-B27)
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72
Q

Poorly staining
Causes Lymphogranuloma venereum, characterized by nodules and vesicles on the genitals, venereal buboes, and elephantiasis of the genitals with rectal strictures

A 
Chlamydia trachomatis
(results from infection of the most invasive serovars L1, L2, and L3; this sexually transmitted disease progresses through primary, secondary, and tertiary stages)
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73
Q

Poorly staining

Causes Q fever, an interstitial pneumonia, resulting from the inhalation of the organism

A 
Coxiella burnetii
(unlike other rickettsial diseases, this organism is NOT transmitted by the bite of an arthropod, does NOT cause a rash, and CANNOT be detected by the classical serologic test for Rickettsia, the Weil-Felix test)
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74
Q

Poorly staining
This organism grows in warm, moist environments (contaminated air conditioner systems) and causes a potential life-threatening pneumonia in patients with lung disease

A

Legionella pneumophila

this organism, often visualized with Dieterle silver stain, also causes a less severe form known as Pontiac fever

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75
Q

Poorly staining

One of the most common opportunistic bacterial infections in AIDS patients

A

Mycobacterium avium-intracellulare

this disease presents similarly to TB and is acquired from soil, birds, or other animals

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76
Q

Poorly staining

Infection results in the destruction of skin and cartilage, resulting in a leonine facies and limb deformities

A 
Mycobacterium leprae
(leprosy, or Hansen disease, presents as a spectrum between two extremes, from tuberculoid leprosy associated with good prognosis to lepromatous leprosy, in which numerous acid-fast bacilli are stuffed in macrophages = Lepra cells)
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77
Q

Poorly staining
Infection results in the destruction of peripheral nerves, resulting in anesthesia followed by atrophy and autoamputation

A 
Mycobacterium leprae
(this acid-fast bacilli has a long generation time, approximately 13 days, and cannot be cultivated in the laboratory)
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78
Q

Poorly staining
Primary infection results in subpleural parenchymal lesions and enlarged caseous lymph nodes (Ghon complex) and reactivation can result in cavitary lesions in the upper lung lobes

A

Mycobacterium tuberculosis

diagnosis is confirmed by finding acid-fast bacilli in the sputum or in cultures that take several weeks to grow

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79
Q

Poorly staining

The classic presentation of infection with this organism includes fever, night sweats, fatigue, and weight loss

A

Mycobacterium tuberculosis

presents similarly to other granulomatous infections such as histoplasmosis or coccidiomycosis

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80
Q

Poorly staining
Infection can result in the involvement of vertebrae (Pott disease) with spread to form a psoas abscess and, in immunocompromised patients, overwhelming dissemination

A

Mycobacterium tuberculosis
(although rare in the U.S., incidence of infections are increasing in immunocompromised patients and urban populations, with high incidence of multidrug-resistant strains)

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81
Q

Poorly staining
Immunization employs the use of Bacillus Calmette Guerin (BCG), one of the only live attenuated bacterial vaccine available

A 
Mycobacterium tuberculosis
(the test for exposure to TB involves injection of a small amount of partially purified derivative [PPD] and detecting a delayed type hypersensitivity reaction; recipients of the vaccine [an attenuated strain of M. bovis] have a positive PPD)
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82
Q

Poorly staining
A prominent cause of community-acquired pneumonia, symptoms normally include a hacking, nonproductive cough (atypical pneumonia)

A 
Mycoplasma pneumoniae
(one of the smallest free-living bacteria, has no cell wall, and causes an interstitial inflammation rather than intra-alveolar exudates)
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83
Q

Poorly staining

Causes “Walking pneumonia” with the potential to develop a self-limiting hemolytic anemia

A 
Mycoplasma pneumoniae
(untreated patients develop IgM autoantibodies to red blood cells, termed acute cold agglutinins)
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84
Q

Poorly staining

Associated with overcrowding and transmitted by the human body louse, this organism causes Epidemic typhus

A 
Rickettsia prowazekii
(characterized by extreme fever, myalgias, and a rash; a less severe form of the disease, Endemic typhus, results from Rickettsia typhi)
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85
Q

Poorly staining

Transmitted by ticks, infection results in a petechial rash with involvement of the palms and soles

A 
Rickettsia rickettsii
(the causative agent of Rocky Mountain spotted fever is an obligate intracellular organism seen with Giemsa staining; despite its name, it is endemic to the eastern U.S.)
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86
Q

Poorly staining
Transplacental infection can result in a triad of interstitial keratitis, Hutchinson teeth, and 8th cranial nerve deafness

A 
Treponema pallidum
(infection results in osteochondritis and periostitis and contributing as well to other defects such as destruction of the vomer, leading to a saddle nose deformity; other bone defects include mulberry molars and saber shin deformities)
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87
Q

Poorly staining

Long-term consequences of untreated disease include tabes dorsalis and aneurysms of the ascending aorta

A 
Treponema pallidum
(tertiary syphilis can lead to paresis and is the leading cause of aneurysms of the ascending aorta with a characteristic tree-barking appearance)
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88
Q

Poorly staining

The disease can manifest with a maculopapular rash on the palms and soles, and condyloma lata

A

Treponema pallidum
(secondary syphilis presents with a rash and gray flattened wart-like lesions on the anogenital, axillary, and oral areas; these condyloma lata are not to be confused with condyloma acuminatum seen with HPV infection)

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89
Q

Poorly staining

Initial infection presents with a painless ulcer on the genitals known as a chancre

A 
Treponema pallidum
(the characteristics lesion of primary syphilis is highly contagious and contains numerous spirochetes viewed by dark field light microscopy or by immunofluorescent microscopy)
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90
Q

Poorly staining
Patients with SLE are often positive for serologic tests for this organism even if not infected (biologic false positive)

A

Treponema pallidum
(screening tests like the rapid plasma reagin or Venereal Disease Research Laboratory [VDRL] are based on finding antibodies to cardiolipin, which patients with SLE make; the most specific test is the fluorescent treponemal antibody [FTA-Abs] test)

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91
Q

Poorly staining
The organism is exquisitely sensitive to penicillins; treatment can result in rash, fever, and hypotension (Jarisch-Herxheimer reaction)

A

Treponema pallidum
(treatment results in rapid death of the organism with release of toxic products that cause symptoms that can be relieved by anti-inflammatory agents)

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92
Q

Poorly staining

This organism that lacks a cell wall is the cause of recurrent urinary tract infections

A

Ureaplasma urealyticum

related to Mycoplasma pneumoniae, infection is associated with the development of urinary calculi

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93
Q

Produces a trivalent exotoxin composed of protective antigen, edema factor, and lethal factor

A

Bacillus anthracis
(protective antigen mediates cell binding, edema factor is a secreted adenylate cyclase, and lethal factor causes CNS depression)

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94
Q

One of the virulence factors of this organism is an anti-phagocytic capsule composed of D-glutamic acid

A 
Bacillus anthracis
(althought typically composed of polysaccharides, other organisms with unique capsular components include sialic acid in Streptococcus agalactiae and hyaluronic acid in Pasteurella multocida)
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95
Q

Produces a typical AB toxin that catalyzes the transfer of ADP-ribose from NAD+ to the inhibitory G protein subunit (Gi)

A 
Bordetella pertussis
(interference of G protein-coupled receptors such as those employed by chemokines results in significant lymphocytosis; other virulence factors include filamentous hemagglutinin and tracheal cytotoxin)
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96
Q

Produces an exotoxin that blocks the release of acetylcholine at the neuromuscular junction

A

Clostridium botulinum

treatment includes the use of an antitoxin produced in horses, with the possibility of serum sickness

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97
Q

The toxin produced by this organism can be used in minute amounts to treat dystonias, strabismus, and wrinkles

A

Clostridium botulinum

toxin causes a flaccid paralysis of injected muscles

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98
Q

Produces an AB toxin that ADP-ribosylates the small GTP binding protein Rho

A

Clostridium difficile

results in the depolymerization of the cytoskeleton with necrosis of the colonic epithelium

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99
Q

Produces a lecithinase and hyaluronidase that results in cellulitis and myonecrosis

A 
Clostridium perfringens
(the lecithinase can be demonstrated by culturing on egg yolk agar; normally the organism produces a double zone of hemolysis on blood agar)
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100
Q

The toxin elaborated by this organism inhibits the release of the inhibitory neurotransmitters, GABA, and glycine, resulting in a spastic paralysis

A

Clostridium tetani
(the DaPT vaccine includes the highly immunogenic tetanus toxoid; a booster is recommended every 10 years and also after a puncture wound)

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101
Q

A virulence factor produced by these two organisms is a typical AB toxin that catalyzes the transfer of ADP-ribose from NAD+ to elongation factor-2

A

Corynebacterium diptheria and Pseudomonas aeruginosa

ADP ribosylation of EF-2 results in the inhibition of protein synthesis and death of the cell

102
Q

Produces a heat stable toxin Sta, that stimulates the production of cGMP, with similar effects to those of increased cAMP

A

Enterotoxigenic Escherichia coli

in addition, the organism produces a STb toxin that is cyclic nucleotide independent

103
Q

Virulence factor found in the outer leaflet of the cell wall of gram-negative organisms

A

Lipopolysaccharide (LPS)
(composed of Lipid A, a core polysaccharide, and O antigen, LPS leads to activation of macrophages with the release of IL-1, with the development of disseminated intravascular coagulation and septic shock)

104
Q

The virulence factors associated with this organism include the ability to grow intracellularly and the production of cord factor

A

Mycobacterium tuberculosis

cord factor is thought to contribute to the formation of granulomas

105
Q

Produces a toxin that irreversibly inactivates the 60S ribosomal subunit with the cessation of protein synthesis and cell death

A

Shigella dysenteriae

toxins similar to Shiga toxin are produced by enterohemorrhagic E. coli and are known as verotoxins

106
Q

Produces exfoliant toxin

A

Staphylococcus aureus

the toxin causes an exfoliative dermatitis, Scalded skin syndrome, that appears as a sunburn-like rash

107
Q

Produces Toxic shock syndrome toxin

A

Staphylococcus aureus
(Toxic shock syndrome, associated with the use of superabsorbent tampons, results from the production of this toxin, which causes polyclonal activation of T cells through antigen-independent activation of the T-cell receptor)

108
Q

Protein A is a major virulence factor

A

Staphylococcus aureus

binds to the Fc region of an antibody, preventing complement fixation and phagocytosis

109
Q

The three major pyogens for which a polysaccharide capsule is the major virulence factor

A

Streptococcus pneumoniae
Haemophilus influenzae
Neisseria meningitidis
(the capsule prevents opsonization by host cell immunoglobulins)

110
Q

Produces erythrogenic toxin, resulting in Scarlet fever

A 
Streptococcus pyogenes (Group A)
(erythrogenic toxin is a phage-encoded superantigen that causes the rash often accompanying pharyngitis)
111
Q

M antigen is the most important virulence factor

A 
Streptococcus pyogenes (Group A)
(prevents phagocytosis, and antibodies to this molecule underlie the long-term sequelae of infection, namely, chronic rheumatic heart disease)
112
Q

Produces an AB toxin that transfers ADP-ribose from NAD+ to the stimulatory G protein subunit (Gs)

A

Vibrio cholerae
(similar to the labile toxin [LT] of enterotoxigenic E. coli, this toxin results in the increase of cAMP with hypersecretion of Cl- and HCO3- with the osmotic reflux of up to 30 L of water/day)

113
Q

Fungi

Produces a toxin that results in liver damage upon ingestion of wild mushrooms

A

Amanita species

ingestion may result in life-threatening fulminant hepatitis, requiring liver transplant

114
Q

Fungi

Produces the carcinogen aflatoxin and is a common contaminant of moldy nuts and grains

A

Aspergillus favus
(aflatoxins contribute to the development of hepatocellular carcinoma and act synergistically with HBV to promote carcinogenesis)

115
Q

Fungi

Proliferation of this organism within the lung causes a “fungus ball” that must be removed surgically

A

Aspergillus fumigatus

microscopically the organism grows as septate hyphae, branching at 45 degree angles

116
Q

Fungi

Although an opportunistic mycosis, it can cause hypersensitivity pneumonitis such as Farmer’s Lung

A

Aspergillus fumigatus

resulting from inhalation of moldy hay

117
Q

Fungi

Systemic mycosis that begins as lower respiratory tract infection and may disseminate to cause warty-like skin lesions

A

Blastomyces dermatitidis
(results in granulomatous lung lesions similar to tuberculosis; may also result in skeletal and genitourinary manifestations)

118
Q

Fungi

Systemic mycosis endemic to the southeastern U.S.

A

Blastomyces dermatitidis

fungi appears in infected tissue as yeast with broad-based budding

119
Q

Fungi

Causes cottage cheese-like vaginal discharge

A

Candida albicans

predisposing factors include immunosuppression, diabetes, obesity, and the use of broad-spectrum antibiotics

120
Q

Fungi
Causes white curd-like patches on the mucocutaneous membranes of the mouth and extend downward to cause esophagitis in immunocompromised patients

A

Candida albicans
(in addition to causing thrush, C. albicans is a common cause of tinea unguium [fungal infection of the nails] and diaper rash)

121
Q

Fungi

Most common mycotic pathogen

A 
Candida albicans
(althought a yeast, it can form pseudohyphae in infected tissue and form characteristics germ tubes at 37 C under laboratory conditions)
122
Q

Fungi

Systemic mycosis endemic to the San Joaquin Valley in southern California

A 
Coccidioides immitis
(causes "Valley Fever", characterized by arthralgias, cough, and fever)
123
Q

Fungi

Found within infected tissue as spherules that rupture to release endospores

A

Coccidioides immitis

dimorphic fungi with contraction of infection by inhalation of arthrospores in the sand and soil

124
Q

Fungi

The only mycotic pathogen with a capsule

A

Cryptococcus neoformans

visualized with an India ink test; capsule excludes ink, providing contrast

125
Q

Fungi

Causes meningitis in patients with underlying immunodeficiency, especially AIDS

A

Cryptococcus neoformans
(associated with pigeon droppings, this fungus grows within the Virchow-Robin vascular spaces of the brain, resulting in “soap bubble lesions”)

126
Q

Fungi

Causes cutaneous infections such as tinea corporis, tinea cruris (jock itch), and tinea pedis (athlete’s foot)

A

Dermatophytes
(typically caused by dermatophytes of the genera Trichophyton spp. and result in scaly hypo- or hyperpigmented annular pruritic lesions)

127
Q

Fungi

Associated with the inhalation of spores from bird or bat droppings in the Ohio and Mississippi River Valley

A 
Histoplasma capsulatum
(histologically characterized by macrophages stuffed with numerous yeast cells)
128
Q

Fungi

Most common pulmonary mycotic infection with symptoms ranging from asymptomatic to tuberculosis-like symptoms

A

Histoplasma capsulatum

in immunocompetent individuals, infection often resolves, with calcification of hilar lymph nodes

129
Q

Fungi

Causes tinea versicolor, which manifests as patches of hyper- and hypopigmentation on the trunk

A 
Malassezia furfur
(found in skin scales and has a characteristic spaghetti and meatballs appearance [yeast clusters and short, curved septate hyphae])
130
Q

Fungi

Most common cause of tinea capitis, ringworm of the scalp

A

Microsporum canis
(common in prepubescent children with pets; the natural inhibitor of Microsporum spp. growth, undecylenic acid, is produced in the sebum of postpubertal individuals)

131
Q

Fungi

Results in rhinocerebral disease, primarily in patients with diabetic ketoacidosis or leukemia

A

Mucor and Rhizopus species
(distinct from other human fungal pathogens in that these species cause disease in their sexual life cycle and display nonseptate hyphae branching at a 90 degree angle or wider)

132
Q

Fungi
This organism grows as multiple budding yeasts that appear as a “captain’s wheel” and causes disease almost exclusively in men

A 
Paracoccidioides braziliense
(this granulomatous lung disease occurs primarily in Central and South America, with >90% of cases seen in males)
133
Q

Fungi

Causes an alveolar pneumonia, typically in AIDS patients

A

Pneumocystis carinii
(previously thought to be a protozoa, this fungus causes a foamy, amorphous alveolar exudate and is seen as a cup- or boat-shaped cyst upon staining with silver methenamine)

134
Q

Fungi

Causes the most common subcutaneous mycosis, Rose handler’s disease

A

Sporothrix schenckii

transmitted by the prick of a contaminated thorn; treated with a dilute solution of potassium iodide [KI] in milk

135
Q

Protozoa

Transmitted by the same tick as that which carries Lyme disease, infection results in similar manifestations as malaria

A

Babesia microti

often mistaken for P. falciparum, the organism be detected in RBCs as a “Maltese cross”, which is diagnostic

136
Q

Protozoa

Causes a self-limiting diarrhea in immunocompetent individuals or life-threatening intractable diarrhea in AIDS patients

A

Cryptosporidium parvum

infection is associated with the consumption of water contaminated with infected animal feces

137
Q

Protozoa

Dissemination to the liver can result in abscess formation with a characteristic anchovy paste aspirate

A

Entamoeba histolytica

the organism can form an amoeboma with the potential for penetration of the serosa and peritonitis

138
Q

Protozoa

Common cause of amebic dysentery, infection leads to the formation of flask-shaped ulcers in the colonic mucosa

A

Entamoeba histolytica

the finding of trophozoites with ingested RBCs is pathognomonic

139
Q

Protozoa

The only common pathogenic protozoa of the small intestine

A

Giardia lamblia
(a heart-shaped symmetrical trophozoite with two nuclei, four pairs of flagella, and a large sucking disk for adherence to the mucosal surface)

140
Q

Protozoa

Causes flatulence and diarrhea with steatorrhea and the production of bulky greasy foul-smelling stool

A

Giardia lamblia
(infection is more common among day-care children, campers consuming contaminated stream water, and homosexual engaging in oral-anal contact)

141
Q

Protozoa

Infection with different species results in dermal, mucocutaneous, and visceral forms of the disease

A

Leishmania spp.
(dermal leishmaniasis is due to L. tropica, the mucocutaneous form is due to L. braziliensis, and the most severe form, visceral leishmaniasis, is due to L. donovani and can result in skin hyperpigmentation or kala-azar)

142
Q

Protozoa

Transmitted by the sandfly, the amastigote stage survives and multiplies within macrophages

A

Leishmania spp.

the only protozoan parasite capable of replication within the phagolysosomes of reticuloendothelial cells

143
Q

Protozoa
Free-living flagellated amoeba, acquired by swimming in freshwater ponds, causing a fulminant meningoencephalitis with death within a week

A

Naegleria fowleri
(another free-living amoebum, Acanthamoeba castellani, causes less severe disease, typically limited to corneal ulceration and keratitis)

144
Q

Protozoa

Blackwater fever

A

Plasmodium falciparum
(seen in P. falciparum malaria, in which infected cells are abnormally adherent and cause thrombosis and ischemia with hemolysis, resulting in hemoglobinuria)

145
Q

Protozoa

Transmitted by the female Anopheles mosquito, with infection of RBCs and hepatocytes

A

Plasmodium spp.
(an obligate intracellular parasite, Plasmodium is typically seen as ring- or crescent-shaped forms within RBCs on a Giemsa-stained peripheral blood smear)

146
Q

Protozoa
Some resistance to infection is provided to patients with sickle cell disease/trait, Glucose-G-phosphate dehydrogenase deficiency, and thalassemia

A

Plasmodium spp.

symptoms of malaria include cyclic fevers [every 48 hr = P. falciparum, every 72 hr = P. malariae], headache, anemia

147
Q

Protozoa
Exposure of nonimmune mothers results in fetal transmission with the potential for stillbirth and intracerebral calcifications

A

Toxoplasma gondii
(infection may be acquired from cysts in raw or undercooked meat or aerosolization of infected cat feces from litter boxes)

148
Q

Protozoa
Usually asymptomatic in immunocompetent individuals, infection in an AIDS patient can result in fulminant, life-threatening encephalitis

A

Toxoplasma gondii
(visualized radiographically as a ring-enhancing mass on CT scan; other ring-enhancing masses include cerebral abscess and Glioblastoma multiforme)

149
Q

Protozoa

A common cause of vaginitis often presents with vulvo-vaginal pruritus, with a profuse frothy discharge

A

Trichomonas vaginalis

causes strawberry mucosa, spotty reddening and edema of the affected mucosa

150
Q

Protozoa
Identified as pear-shaped flagellated trophozoites with undulating movements on a wet-mount slide of vaginal or urethral discharge

A

Trichomonas vaginalis

typically a sexually transmitted disease, growth is associated with an abnormally alkaline pH of the vagina

151
Q

Protozoa
Transmitted by the tsetse fly, this protozoa causes African sleeping sickness, characterized by cyclic fevers, encephalitis, slurred speech, and somnolence

A 
Trypanosoma brucei
(the organism evades the immune system by genetic rearrangement of its variable surface glycoproteins [VSG])
152
Q

Protozoa

Can destroy the myenteric plexus, resulting in megaesophagus and megacolon

A

Trypanosoma cruzi
(transmitted by the droppings of the reduviid bug [“kissing bug”], often with the initial development of unilateral swelling of the eyelids [Romana’s sign])

153
Q

Protozoa

A major cause of heart disease in Central and South America

A 
Trypanosoma cruzi
(acute forms of Chagas disease lead to direct invasion of the myocardium with inflammation; the chronic forms of disease involve autoimmune destruction with the development of dilated cardiomyopathy with life-threatening arrhythmias)
154
Q

Helminths

Migration of larval nematodes below the skin results in serpiginous urticarial trails on the skin (Creeping eruptions)

A

Ancylostoma braziliense and other animal hookworms

infection is acquired by contact with sand-containing feces of dogs and cats

155
Q

Helminths

Chronic infection with this hookworm constitutes an important cause of anemia worldwide

A 
Ancylostoma duodenale
(leads to iron deficiency anemia because each worm consumes as much as 0.25 ml blood/day)
156
Q

Helminths

Most common helminth infection worldwide

A 
Ascaris lumbricoides
(as much as 1/4 of the world population is infected; infection causes GI obstruction, granulomas of the biliary tree, lives abscesses, and hypersensitivity pneumonitis)
157
Q

Helminths

Infection is associated with damage to the biliary tract and the development of cholangiocarcinoma

A

Clonorchis sinensis

associated with the consumption of infected freshwater fish

158
Q

Helminths

Infection can be associated with megaloblastic anemia

A 
Diphyllobothrium latum
(this enormous fish tapeworm absorbs dietary vitamin B12, resulting in B12 deficiency in the host)
159
Q

Helminths
Removal of this nematode is traditionally accomplished by slowly twisting it around a stick to remove it from beneath the skin

A 
Dracunculus medinensis
(infection is acquired by consuming water contaminated by the intermediate host, the cyclops, a microscopic crustacean)
160
Q

Helminths

Larvae form large space-occupying hydatid cysts in the liver and lung, and leakage of fluid can result in anaphylaxis

A 
Echinococcus granulosus (dog tapeworm)
(because herbivores such as sheep are usually an intermediate host for the dog tapeworm, infection commonly presents in the context of a sheep farmer with many sheepdogs)
161
Q

Helminths

Causes perianal pruritus, with diagnosis confirmed by the recovery of the egg from the anus with scotch tape

A 
Enterobius vermicularis (pinworm)
(most common helminth infection in the U.S. and often associated with day-care institutions)
162
Q

Helminths

Infection results in subcutaneous “caliber” swellings and can be seen migrating across the eye beneath the conjunctiva

A

Loa loa

infection is transmitted by the bite of the mango fly, Chrysops

163
Q

Helminths

Endemic to Africa, especially along river basins, infection can result in River blindness

A

Oncocerca volvulus
(transmitted by the blackfly, this nematode also causes loss of elasticity of the skin with significant dependent edema [i.e. hanging groin])

164
Q

Helminths

Infection of the bladder is associated with the development of squamous cell carcinoma of the bladder

A

Schistosoma hematobium
(endemic to Egypt and Sudan and associated with wading through moist soil while barefoot; diagnosis is confirmed by finding spherical eggs with a terminal spine in the urine)

165
Q

Helminths

The smallest of all intestinal nematodes, high worm burden is possibly the result of autoinfection

A 
Strongyloides stercoralis
(it is the only intestinal nematode capable of completing its lifecyle within the human host)
166
Q

Helminths
One of the most common cestode infections in the U.S. and associated with the consumption of improperly cooked contaminated beef

A 
Taenia saginata (beef tapeworm)
(usually results in vague abdominal pain, although the tapeworm can grow to several meters in length)
167
Q

Helminths

Infection with the larval form of this tapeworm from feces-contaminated water can lead to cysticercosis

A 
Taenia solium (pork tapeworm)
(results in the growth of the larvae in brain, resulting in a Swiss cheese appearance of the cerebral hemispheres)
168
Q

Helminths
Accidental transmission of these nematodes from pet feces (in sandboxes or on sandy beaches) results in Visceral larva migrans

A

Toxocara canis and Toxocara cati

symptoms include eosinophilia, pneumonitis, and vision loss

169
Q

Helminths

Infection is acquired by consuming cysts in under-cooked contaminated pork

A

Trichinella spiralis

infection results in flu-like symptoms, diarrhea, myalgias, and periorbital edema

170
Q

Helminths
Rectal prolapse is a potential complication in children resulting from straining during defecation with infection of this nematode

A 
Trichuris trichiura (whipworm)
(diagnosis is based on finding bile-stained, barrel-shaped eggs with polar plugs)
171
Q 
Helminths
Filiariasis (Elephantiasis)
A 
Wucheria bancrofti
(organism causes obstruction of lymph vessels resulting in edema with swelling of the legs and genitalia)
172
Q

DNA Virus

Major cause of epidemic conjunctivitis (Pink eye)

A

Adenovirus

various subtypes are also associated with pharyngitis and gastroenteritis

173
Q

DNA Virus

Major cause of retinitis, leading to blindness, in an immunocompromised patient

A

Cytomegalovirus (CMV)
(can also cause life-threatening interstitial pneumonia in such patients and heterophil-negative infectious mononucleosis in immunocompetent individuals)

174
Q

DNA Virus

Most common viral cause of congenital abnormalities in the U.S.

A

Cytomegalovirus (CMV)

infected cells display characteristics “owl eye” intranuclear viral inclusions

175
Q

DNA Virus

Infection results in production of heterophil antibodies

A

Epstein-Barr Virus (EBV)
(viral infection results in the polyclonal activation of B cells with the production of antibodies to sheep RBCs [heterophil antibodies] that can be detected with the Monospot test)

176
Q

DNA Virus

Major cause of infectious mononucleosis (kissing disease)

A

Epstein-Barr Virus (EBV)
(characterized by weeks of fever, malaise, and lymphadenopathy, the peripheral blood contains an abundance of atypical lymphs, which are T cells that recognize EBV-infected cells)

177
Q

DNA Virus

Infection is associated with Burkitt lymphoma and Nasopharyngeal carcinoma

A

Epstein-Barr Virus (EBV)
(Burkitt lymphoma is more commonly associated with EBV in Africa; Nasopharyngeal carcinoma is more common in patients from Asia)

178
Q

DNA Virus

Encodes an RNA-dependent DNA polymerase (reverse transcriptase)

A

Hepatitis B Virus (HBV)

the virus produces its DNA genome through a single mRNA transcript, requiring the presence of a reverse transcriptase

179
Q

DNA Virus

Appear in the serum as Dane particles and as large amounts of filaments of excess surface antigen

A

Hepatitis B Virus (HBV)

the surface antigen [HBsAg] is now produced by recombinant DNA technology and is given as a vaccine

180
Q

DNA Virus

A major cause of Hepatocellular carcinoma worldwide

A

Hepatitis B Virus (HBV)
(although less likely to progress to either cirrhosis or carcinoma than HSV, the worldwide prevalence, especially in Africa, makes HBV the leading cause)

181
Q

DNA Virus

Major cause of sexually transmitted and vertically transmitted hepatitis

A

Hepatitis B Virus (HBV)
(histologically, infected cells appear as ground glass hepatocytes because of the presence of excess surface antigen within the cytoplasm)

182
Q

DNA Virus

Infection with this virus is a leading cause of corneal blindness in the U.S.

A

Herpes Simplex Virus-1 (HSV-1)

keratoconjunctivitis results in dendritic ulcers that can be visualized with fluorescein staining

183
Q

DNA Virus

Infection results in Cowdry Type A intranuclear inclusions and multinucleated giant cells

A

Herpes Simplex Virus-1 (HSV-1)
(one of the most common human viral infections, the virus enters broken skin and remains latent in the trigeminal ganglion, with spontaneous reactivation triggered by axonal injury, stress, or UV light)

184
Q

DNA Virus

Leading cause of sporadic encephalitis in the U.S.

A

Herpes Simplex Virus-1 (HSV-1)

commonly affects the temporal lobe

185
Q

DNA Virus

Most common cause of vesiculo-ulcerative lesions of the penis or vagina

A

Herpes Simplex Virus-2 (HSV-2)
(reactivation of the virus is common, because the virus remains latent in the lumbar and sacral ganglia; detected using the Tzanck test)

186
Q

DNA Virus

Infection causes Roseola infantum or Sixth disease

A

Herpes Virus 6

a common, mild, childhood disease characterized by high fever and a skin rash

187
Q

DNA Virus

Causes cranberry-pigmented lesions on AIDS patients

A

Herpes Virus 8

Kaposi sarcoma is a tumor of blood vessels characterized by a disarray of vascular channels filled with RBCs

188
Q

DNA Virus

Infection is linked to premalignant lesions on the vulva, cervix, penis, and anus

A

Human Papilloma Virus (HPV)
(viral oncoprotein E6 binds to p53 and viral oncoprotein E7 binds to Rb, stimulating infected cells to undergo uncontrolled growth)

189
Q

DNA Virus

Infection of keratinized tissue results in the formation of warts on the hands and feet

A

Human Papilloma Virus (HPV)
(typically caused by infection with HPV 1-4, with the development of warts on the hands [Verruca Palmaris] and feet [Verruca Plantaris])

190
Q

DNA Virus

Infection causes cauliflower-like lesions on the external genitals and perianal areas

A

Human Papilloma Virus (HPV)

Condyloma acuminatum is microscopically characterized by the presence of vacuolated infected cells, termed koilocytes

191
Q

DNA Virus
Reactivation of latent viral infection in immunocompromised patients can result in Progressive multifocal leukoencephalopathy (PML)

A

JC Virus

this polyomavirus causes foci of demyelination, surrounded by oligodendrocytes with viral inclusions

192
Q

DNA Virus
This contagious virus causes benign epithelial tumors that appear as pearly, umbilicated nodules with a central caseous plug

A

Molluscum contagiosum
(these lesions caused by this poxvirus occur as clusters on the trunk, genitalia, and extremities; it is transmitted by towels, barbers, swimming pools, and sexual activity)

193
Q

DNA Virus

Causes aplastic crisis in patients with sickle cell anemia, thalassemias, and acquired hemolytic anemias

A

Parvovirus B19

virion replicates best in rapidly dividing erythroblasts, resulting in cell lysis

194
Q

DNA Virus

Infection of a child results in a “slapped cheek” appearance

A 
Parvovirus B19
(this single-stranded DNA virus cases Erythema infectiosum or Fifth disease)
195
Q

DNA Virus

The only DNA virus that replicates solely in the cytoplasm and that carries its own DNA-dependent polymerases

A

Poxvirus
(the largest of all viruses, it appears brick-shaped by electron microscopy, and causes characteristic Guarnieri inclusion bodies when replicating in cells)

196
Q

DNA Virus

Found as a contaminant in preparations of polio vaccines produced in monkey cell culture

A

SV40
(this polyoma virus is typically a simian virus, which can cause tumors in mice, although no pathogenic effects have been reported in humans)

197
Q

DNA Virus

Causes chickenpox upon initial infection, and shingles upon reactivation

A

Varicella-Zoster Virus (VZV)
(the only herpes virus with a live attenuated vaccine; reactivation most commonly occurs along the dermatomal distribution of the ophthalmic division of the trigeminal nerve)

198
Q

DNA Virus

Infection results in the successive appearance of macules, papules, vesicles, and crusts all seen simultaneously

A

Varicella-Zoster Virus (VZV)

severe infection can result in pneumonia with multinucleated giant cells

199
Q

DNA Virus

Associated with Reye syndrome when the accompanying fever is treated with aspirin

A

Varicella-Zoster Virus (VZV)

Reye syndrome is an acute encephalopathy associated with fatty infiltration of the liver, which is often fatal

200
Q

RNA Virus

Group of Togaviruses transmitted by mosquitoes leading to encephalitis

A

Alphavirus
(this genus includes Eastern equine encephalitis virus [EEE], Western equine encephalitis virus [WEE], and Venezuelan equine encephalitis [VEE])

201
Q

RNA Virus

A grouping of viruses that are transmitted by mosquitoes and ticks

A

Arboviruses

the group contains members of the Flavivirus family, Togavirus family, and Bunyavirus family

202
Q

RNA Virus

Only bunyavirus member causing diseases endemic to the U.S.

A

California Encephalitis Virus (including La Crosse virus)

results in mild encephalitis, sometimes only meningitis

203
Q 
RNA Virus
Causes pleurodynia (Bornholm disease)
A

Coxsackie B Virus

sudden onset of stabbing chest pain with waxing and waning symptoms

204
Q

RNA Virus

Most common cause of viral myocarditis

A

Coxsackie B Virus

usually self-limiting, but may cause fatal arrhythmias or lead to dilated cardiomyopathy

205
Q

RNA Virus

Causes herpangina

A

Coxsackievirus

discrete vesicles on the throat and tongue with pain and difficulty swallowing

206
Q

RNA Virus

Infection may result in destruction of the pancreas with resultant insulin-dependent diabetes mellitus

A

Coxsackieviruses B3 and B4

may be due to molecular mimicry owing to shared antigens between virus and pancreatic beta cells

207
Q

RNA Virus

Causes a severe hemorrhagic fever with outbreaks in Zaire and Sudan

A

Ebola virus
(another filovirus family member, Marburg virus, has been associated with infection of laboratory personnel working with monkey tissue)

208
Q

RNA Virus

Infection leads to severe hemorrhage and renal failure

A

Hantavirus

a member of the Bunyavirus family with 3 segments of RNA

209
Q

RNA Virus

Infection is associated with ingestion of raw shellfish from fecally contaminated water

A

Hepatitis A Virus (HAV)

the virus is transmitted via the fecal/oral route and causes an acute hepatitis with no chronic carrier state

210
Q

RNA Virus

Major cause of post-transfusion hepatitis

A

Hepatitis C Virus (HCV)
(this Flavivirus often results initially in subclinical infection although it is a major cause of chronic hepatitis and cirrhosis in the U.S.; it is the hepatitis virus most likely to result in hepatocellular carcinoma)

211
Q

RNA Virus

Replication-deficient virus, requiring the presence of hepatitis B virus for productive infection

A

Hepatitis D Virus (HDV)
(the HDV viral particle, known as the Dane particle, requires packaging into hepatitis B surface antigen to be infectious)

212
Q

RNA Virus

Infection is associated with a high mortality rate in infected pregnant women

A

Hepatitis E Virus (HEV)
(this Calicivirus is transmitted by the fecal/oral route, as with hepatitis A, and is most prevalent in developing nations)

213
Q

RNA Virus

Infection leads to the destruction of T cells, with the development of life-threatening opportunistic infections

A

Human Immunodeficiency Virus (HIV)
(opportunistic infections include CMV infection, Kaposi sarcoma, Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium-intracellulare)

214
Q

RNA Virus

Virus binds to CD4+ cells via viral glycoprotein gp120

A

Human Immunodeficiency Virus (HIV)

entry of virus requires the presence of chemokine receptors CCR5 on monocyte/macrophages or CXCR4 on T lymphocytes

215
Q

RNA Virus

Retrovirus that causes oncogenic transformation of CD4+ T cells

A

Human T-Cell Lymphotropic Virus-1 (HTLV-1)

this virus, related to HIV, is endemic to Japan and the Caribbean basin, and also causes Tropical spastic paraparesis

216
Q

RNA Virus

Treatment with salicylates for this viral cause of respiratory symptoms may result in Reye syndrome in children

A 
Influenza virus (Orthomyxovirus)
(in children, this virus can also cause croup, otitis media, muscle aches, and a high fever; influenza and retroviruses are the only RNA viruses that replicate in the nucleus)
217
Q

RNA Virus
Changes in the viral surface proteins resulting from point mutations; reassortment of genome segments results in epidemics and pandemics

A 
Influenza virus (Orthomyxovirus)
(point mutations in viral hemagglutinin [HA] or neuraminidase [NA] result in antigen drift, whereas reassortment of genes results in antigenic shifts)
218
Q

RNA Virus

Major viral cause of pneumonia, and infection typically predisposes to secondary bacterial pneumonia

A 
Influenza virus (Orthomyxovirus)
(decrease in respiratory mucosal viscosity by viral neuraminidase and destruction of the respiratory epithelium lower the resistance to bacterial superinfection by Staphylococcus spp., Streptococcus spp., and Haemophilus spp. infection)
219
Q

RNA Virus

Infection has been associated with subacute sclerosing panencephalitis (SSPE)

A 
Measles virus
(caused by a defective virus encoding a defective M protein)
220
Q

RNA Virus

Infection leads to an immune-mediated maculopapular rash on the head, trunk, and limbs

A

Measles virus

the presence of Koplik spots, small bluish-white ulcerations on the oral mucosa, are pathognomonic

221
Q

RNA Virus

Giant-cell pneumonia and encephalomyelitis are potential complications

A 
Measles virus
(vaccination for this previously common viral infection is included in the MMR vaccine, along with mumps and rubella)
222
Q

RNA Virus

Infection can result in orchitis, which can lead to sterility

A

Mumps virus

orchitis complicates parotiditis in 20% of infected males

223
Q

RNA Virus

Infection results in swelling of one or both parotids

A

Mumps virus

may result in aseptic meningitis and pancreatitis

224
Q

RNA Virus

Major agent of epidemic gastroenteritis in adults

A 
Norwalk agent
(outbreaks of this Calicivirus are common in institutional settings and on cruise ships)
225
Q

RNA Virus

Leading cause of croup

A 
Parainfluenza virus
(also known as layngotracheobronchitis, obstruction of the larynx results in a characteristics seal-bark cough)
226
Q

RNA Virus

Infection leads to the destruction of the cells of the anterior horn of the spinal cord

A

Poliovirus

viral infection with this picornavirus can lead to denervation atrophy of inntervated muscles with flaccid paralysis

227
Q

RNA Virus

Infection is associated with an aversion to water, foaming at the mouth, and choking (hydrophobia)

A 
Rabies virus
("bullet-shaped" virion can be seen by electron microscopy; causes intracellular viral inclusions in infected cells known as Negri bodies)
228
Q

RNA Virus

Only virus for which post-exposure vaccination is indicated

A 
Rabies virus
(long incubation period allows for the development of a protective immune response, without which CNS symptoms lead invariably to death)
229
Q

RNA Virus

Infection is associated with symptoms of sympathetic over-reactivity (i.e. salivation)

A

Rabies virus

virus binds to the nicotinic acetylcholine receptor

230
Q

RNA Virus

Most important cause of lower respiratory tract infections in infants

A

Respiratory Syncytial Virus (RSV)

virally infected cells often form multinucleated syncytia

231
Q

RNA Virus

Virion contains two identical strands of positive RNA (diploid-like genome)

A

Retrovirus
(the virion also carries an RNA-dependent RNA polymerase, a reverse transcriptase, and an integrase for integration into the host cell genome)

232
Q

RNA Virus

Major cause of upper respiratory tract infections in humans

A

Rhinovirus
(this picornavirus binds and enters epithelial cells via attachment to ICAM-1 and replicates best at 33 C, explaining its predilection for the mucosa of the nasopharynx)

233
Q

RNA Virus

Major cause of diarrhea (gastroenteritis) in young children

A

Rotavirus

this reovirus contains 10-12 segments of dsRNA within two concentric capsids

234
Q

RNA Virus

Teratogenic virus leading to congenital defects of the heart, brain, and eye

A

Rubella virus
(a member of the TORCH group of infectious agents that are capable of crossing the placenta and infecting the developing fetus)

235
Q

RNA Virus
This newly emerging cause of mosquito-borne encephalitis can also be transmitted via blood transfusions and organ transplants, and causes life-threatening symptoms in elderly and immunosuppressed patients

A

West Nile Virus
(Although first reported in Africa in the 1930s, the appearance of this member of the Flavivirus family was first reported in the U.S. in 1999; recent years have seen large outbreaks with thousands of cases and nearly 200 deaths)

236
Q

RNA Virus

Arbovirus that causes severe hepatitis with jaundice and severe gastrointestinal hemorrhage with black vomit

A

Yellow Fever Virus
(infection by this Flavivirus, transmitted by the Aedes mosquito, can be prevented using a vaccine developed from the 17D strain)

237
Q

A unique and recently discovered class of infectious agents that can result in Spongiform encephalitis

A

Prions
(composed only of proteinaceous material, it is highly resistant to most forms of sterilization and can be transmitted iatrogenically [e.g. surfical instruments, cadaveric material], or from consuming contaminated meats)

238
Q

Opportunistic infections common in AIDS patients:

  • Bacterial?
  • Fungal?
  • Protozoal?
  • Viral?
A

Bacterial: Mycobacterium avium-intracellulare
Funal: Pnuemocystis carinii
Protozoal: Toxoplasma gondii, Cryptosporidium parvum
Viral: Cytomegalovirus (CMV), Kaposi sarcoma virus

239
Q

Major sexually transmitted diseases in the U.S.:

  • Bacterial?
  • Protozoal?
  • Viral?
A

Bacterial: Chlamydia trachomatis, Neisseria gonorrhoeae
Protozoal: Trichomonas vaginalis
Viral: Herpes Simplex Virus-2 (HSV-2), Human Immunodeficiency Virus (HIV), Human Papilloma Virus (HPV)

240
Q

Major causes of meningitis:

  • Newborns?
  • Children?
  • Young adults?
  • Elderly (>60 years)?
  • AIDS patients?
A 
Newborns: Streptococcus agalactiae, Escherichia coli
Children: Haemophilus influenzae
Young adults: Neisseria meningitidis
Elderly: Streptococcus pneumoniae
AIDS patients: Cryptococcus neoformans
241
Q

Major causes of pneumonia:

  • Neonates?
  • Children (6 weeks - 18 years)?
  • Adults?
  • Alcoholics?
  • Post-viral?
  • Cystic fibrosis patients?
A

Neonates: Streptococcus agalactiae, Escherichia coli
Children: Respiratory Syncytial Virus
Adults: Mycoplasma pneumonia
Alcoholics: Klebsiella pneumonia
Post-viral: Haemophilus influenzae
Cystic fibrosis patients: Pseudomonas aeruginosa

242
Q

Common nosocomial infections associated with:

  • Newborns?
  • Urinary catheterizations?
  • Renal dialysis patients?
  • Respiratory therapy equipment?
  • Water aerosols?
A

Newborns: Respiratory Syncytial Virus (RSV), Cytomegalovirus (CMV)
Urinary catheterization: Escherichia coli, Proteus spp.
Renal dialysis patients: Hepatitis B Virus (HBV)
Respiratory therapy equipment: Pseudomonas aeruginosa
Water aerosols: Legionella pneumophila

243
Q

Major causes of endocarditis?

  • Subacute endocarditis?
  • Acute endocarditis?
  • IV drug users?
  • Patients with prosthetic valves?
A

Subacute endocarditis: Streptococcus viridans
Acute endocarditis: Staphylococcus aureus
IV drug users: Staphulococcus aureus
Patients with prostetic heart valves: Staphylococcus epidermidis

244
Q

Major causes of osteomyelitis?

  • General population?
  • Sexually active?
  • Drug users?
  • Sickle cell anemia patients?
A

General population: Staphylococcus aureus
Sexually active: Neisseria meningitidis
Drug users: Pseudomonas aeruginosa
Sickle cell anemia patients: Salmonella spp.

245
Q

Major causes of urinary tract infections

A 
Escherichia coli (most common)
Enterococcus faecalis
Klebsiella pneumonia
Proteus mirabilis
Proteus vulgaris
Pseudomonas aeruginosa
Serratia marcescens
Staphylococcus saprophyticus
246
Q

Organisms causing watery diarrhea

A 
Cryptosporidium parvum
Escherichia coli
Vibrio cholerae
Giardia lamblia
Norwalk Agent
Rotavirus
247
Q

Organisms causing a blood diarrhea (dysentery)

A 
Campylobacter jejuni
Escherichia coli (enteroinvasive and enterohemorrhagic)
Salmonella spp.
Shigella dysenteriae
Entamoeba histolytica
248
Q

Major causes of food poisoning

A

Bacillus cereus
Clostridium perfringens
Staphylococcus aureus
Vibrio parahaemolyticus

249
Q

Major causes of transplacental neonatal infections

A 
Toxoplasma gondii
Treponema pallidum
Rubella virus
Cytomegalovirus (CMV)
Herpes simplex virus (HSV)
Human immunodeficiency virus (HIV)
(collectively known as the TORCH group, many of these infection can lead to congenital defects, if acquired in utero)
250
Q

Major causes of transcervical neonatal infections (acquired by vaginal delivery)

A

Candida albicans
Escherichia coli
Listeria monocytogenes
Streptococcus agalactiae

Microbiology (6 decks)

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