Clinical Bacteriology Flashcards

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1
Q

Gram + cocci antibiotic tests: Streptococci

A

Optochin - Viridans is Resistant; Pneumoniae is Sensitive
OVRPS (overpass)
Bacitracin - Group B strep are resistant; group A strep are Sensitive
B-BRAS

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2
Q

Alpha hemolytic bacteria

A

Gram + cocci
Partial reduction of hemoglobin causes greenish or brownish color without clearing growth on blood agar
Strep pneumo (catalase -, optochin sensitive)
Viridans strep (catalase -, optochin resistant)

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3
Q

Beta hemolytic bacteria

A

Gram + cocci
Complete lysis of RBCs –> clear area surrounding colony on blood agar
Staph aureus (catalase & coagulate +)
Strep pyogenes - group A (catalase -, bacitracin sensitive)
Strep agalctiae - Group B (catalase -, bacitracin resistant)

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4
Q

Staphylococcus aureus

A

Gram + bacteria, beta-hemolytic, catalase +, coagulase +, cocci in clusters
VFs: protein A binds Fc-IgG inhibiting complement activation and phagocytosis
Commonly colonizes in nares

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5
Q

Staphylococcus aureus: Inflammatory disease

A

Skin infections, organ abscesses, pneumonia (often after influenza virus infection), endocarditis, septic arthritis, and osteomyelitis

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6
Q

Staphylococcus aureus: Toxin mediated disease

A

Toxic shock syndrome (TSST-1), scalded skin syndrome (exfoliative toxin), rapid onset food poisoning (enterotoxins)
TSST-1: Superantigen that binds to MHC II and TCR, resulting in polyclonal TC activation
TSS presents as fever, vomiting, rash, desquamation, shock, end-organ failure, increased AST, ALT & bilirubin. Associated with prolonged use of vaginal tampons or nasal packaging
Food poisoning due to ingested preformed toxin –> short incubation period followed by non-bloody diarrhea and emesis (enterotoxin is heat stable)

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7
Q

Staphylococcus aureus: MRSA

A

Methicillin-resistant S aureus infection - important cause of serious nosocomial and community acquired infections
Resistant to methicillin and nafcillin because of altered penicillin binding protein

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8
Q

Staphylococcus epidermidis

A

Gram +, catalase +, coagulase -, urease + cocci clusters. Novobiocin sensitive
Found in normal flora of the skin; contaminates blood cultures
Infects prosthetic devices (hip implant, heart valve) and IV catheters by producing adherent bio films

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9
Q

Staphylococcus saprophyticus

A

Gram +, catalase +, coagulase -, urease + cocci in clusters. Novobiocin resistant
Found in normal flora of female genital tract and perineum
Second most common cause (after E.coli) of uncomplicated UTI in young women

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10
Q

Streptococcus pneumoniae

A

Gram +, lancet shaped diplococci. Alpha-hemolytic Optochin sensitive (different from S.viridans)
VFs: encapsulated, IgA protease
Most common cause of: meningitis, otitis media (children), pneumonia, sinusitis
Associated with “rusty” sputum, sepsis in pts with sickle cell disease and splenectomy

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11
Q

Streptococcus Viridans group

A

Gram +, alpha hemolytic cocci. Optochin resistant (different from S.pneumo)
Found in the normal flora of the oropharynx that cause dental caries (strep mutans and strep mitis) and subacute bacterial endocarditis at damaged heart valves (S.sanguinis - makes dextran so which bind to fibrin-platelet aggregates on damaged heart valves).
live in the mouth because they are not afraid of-the-chin (op-to-chin resistant)

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12
Q

Streptococcus pyogenes (Group A)

A

Gram + cocci, beta hemolytic, bacitracin sensitive, pyrrolidonyl arylamidase (PYR) +
Cause: pyogenic (pharyngitis, cellulitis, impetigo, erysipelas), toxogenic (scarlet fever, toxic shock like syndrome, necrotizing fasciitis), immunologic (rheumatic fever, glomerulonephritis)
Abs to M protein enhance host defenses against S.pyogenes but can give rise to RF
ASO tigers detects recent S.pyogenes infection

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13
Q

S.pyogenes and rheumatic fever

A
JONES criteria
Joints: polyarthritis
O: heart, carditis
Nodules: subcutaneous
Erythema margin atom
Sydenham chorea
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14
Q

S.pyogenes and Scarlet Fever

A

Blanching, sandpaper like body rash, strawberry tongue, and circumoral pallor in the setting of group A strep pharyngitis (erythogenic toxin +)

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15
Q

Streptococcus agalctiae (group B streptococci)

A

Gram+ cocci, bacitracin resistant, beta-hemolytic (Hippurate test +, PRY -)
Colonizes vagina; causes pneumonia, meningitis and sepsis mainly in babies (screen pregnant women at 35-37 weeks of gestation. Pts with positive culture receive intrapartum penicillin prophylaxis
Produces CAMP factor, which enlarges the are of hemolysis formed by S.aureus

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16
Q

Streptococcus bovis

A

Gram+ cocci
Colonizes the gut
S.gallalyticus can cause bacterimia and subacute endocarditis (associated with increased risk in pts with CRC) and colon cancer
Bovis in the Blood = Cancer in the Colon

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17
Q

Enterococci

A

Gram+ cocci, catalase -, PYR+, variable hemolysis
enterococci (E.faecalis and E.faeciium) are normal colonic flora that are penicillin G resistant and cause UTI, biliary tract infections and subacute endocarditis (following GI/GU procedures)
VRE (vancomycin resistant enterococci) are an important cause of nosocomial infection
Enterococci can grow in 6.5% NaCl and bile

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18
Q

Bacillus anthracis

A

Gram + spore forming rod that produces anthrax toxin

The only bacteria with a polypeptide capsule (contains D-glutamate)

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19
Q

Cutaneous anthrax

A

Painless papule surrounded by vesicles –> ulcer with black eschar (painless and necrotic) –> uncommonly progresses to bacteremia and cell death

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20
Q

Pulmonary anthrax

A

Inhalation of spores –> flu-like symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis and shock
Also known as woolsorter’s disease

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21
Q

Bacillus cereus

A

Gram + rod
Causes food poisoning. Spores survive cooking rice, keeping rice warm results in germination of spores and enterotoxin formation (AKA reheated rice syndrome)
Emetic type: usually seen with rice and pasta, nausea and vomiting within 1-5 hours. Caused by cereulide (preformed toxin).
Diarrheal type: water, non-bloody diarrhea and GI pain within 8-18 hours.

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22
Q

Clostridia

A

Gram + spore forming, obligate anaerobic rods

Two types of exotoxins (C.tetani, C.botulinum)

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23
Q

Clostridium tetani

A
Produces tetanospasmin (exotoxin) causing tetanus
Tetanus toxin (and botulinum toxin) are pro teases that cleave SNARE proteins for neurotransmitters. Blocks the release of inhibitory neurotransmitters, GABA & glycine, from Renshaw cells in the spinal cord
Causes spastic paralysis, trismus (lockjaw), risks sardonicus (raised eyebrows with an open grin)
Prevent with tetanus vaccine, treat with antitoxin +/- vaccine booster, diazepam and wound debridement
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24
Q

Clostridium botulinum

A

Produces a heat-labile toxin that inhibits ACh release at the neuromuscular junction, causing botulism
In adults, disease is caused by ingestion of preformed toxin. In babies - the ingestion of spores (e.g. Honey) leading to floppy baby syndrome.
Treat with antitoxin

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25
Q

Clostridium perfringes

A

Produces alpha toxin (lecithinase, a phospholipase) that can cause myonecrosis (gas gangrene) and hemolysis
PERFringens PERForates a gangrenous leg
Spores can survive in undercooked food; when ingested, bacteria release heat-labile enterotoxin –> food poisoning

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26
Q

Clostridium difficile

A

Produces two toxins: Toxin A (enterotoxin) that binds to the brush border of the gut. Toxin B (cytotoxin), causes cytoskeleton disruption via actin depolymerization –> diarrhea –> pseudomembranous colitis
Often secondary to antibiotic use, especially clindamycin or ampicillin; associated with PPI use.
Diagnosis: detection of one or both toxins in stool by PCR
Tx: metronidazole, oral vacomycin. For recurrent cases, consider repeating prior regiment, fidaxomicin or fecal microbiota transplant

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27
Q

Corynebacterium diphtheriae

A

Gram + rod (club shaped), black colonies on cystine-telluride agar
Causes diphtheria via Exotoxin encoded by beta-prophase. Potent Exotoxin inhibits protein synthesis via ADP-ribosylation of EF-2
Symptoms: pseudomembranous pharyngitis, lymphadenopathy, myocarditis, and arrhythmias
Lab diagnosis: gram + rods with Metachromatic (blue and red) granules and + Elek test for toxin
Toxoid vaccine prevents diphtheria

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28
Q

Listeria monocytogenes: characteristics

A

Gram + facultative intracellular rod
Acquired by ingestion of unpasteurized dairy products and cold deli meats, via trans placenta transmission, or by vaginal transmission during birth
Forms “rocket tails” via actin polymerization that allow intracellular movement and cell to cell spread across cell membranes, thereby avoiding AV
Characteristic tumbling motility in broth

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29
Q

Listeria monocytogenes: Disease

A

Can cause ammionitis, septicemia, spontaneous abortion in pregnant women
Granuloumatosis infantiseptica, neonatal meningitis
Meningitis in immunocompromised pts
Mild self-limited gastroenteritis in healthy individuals
Tx: ampicillin in infants, immunocompromised and elderly as empirical treatment of meningitis

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30
Q

Nocardia

A

Gram +, form long branching filaments resembling fungi
Aerobe
Acid fast (weak)
Found in soil
Causes pulmonary infections in immunocompromised (can mimic TB but with - PPD); cutaneous infections after trauma in immunocompetent
Treat with sulfonamides (TMP-SMX)

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31
Q

Actinomyces

A

Gram +, form long branching filaments resembling fungi
Anaerobe
Not acid fast
Normal oral, reproductive and GI flora
Causes oral/facial abscesses that drain through sinus tracts, forms yellow “sulfur granules” can also cause PID with IUDs
Treat with penicillin

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32
Q

Mycobacteria

A

Mycobacterium tuberculosis (TB, often resistant to multiple drugs)
-TB symptoms: fever, night sweats, weight loss, cough (non-productive or productive), hemoptysis
-Cord factor creates a “serpentine cord” appearance in virulent M.tb strains; inhibits MP maturation and induces release of TNF-alpha. Sulfatides (surface glycolipids) inhibit pahgolysosomal fusion
M.avium-intracellular even (causes disseminated, non-TB disease in AIDS; often resistant to multiple drugs) Prophylaxis with Azithromycin when CD4+ count

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33
Q

Leprosy (Hansen disease)

A

Caused by mycobacterium leprae (acid fast bacillus that likes cool temperatures) - infecting skin and superficial nerves (glove and stocking loss of sensation
Cannot be grown in vitro.
Reservoir in USA: armadillos
Treatment: dapsone and rifampin for tuberculoid form, clofazimine is added for lepromatous form

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34
Q

Hansen disease: Lepromatous

A

Presents diffuse lay over the skin with leonin facies, and is communicable. Characterized by low cell-mediated immunity with a humoral Th2 response
Lepromatous form can be Lethal

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35
Q

Hansen disease: Tuberculoid

A

Limited to a few heypesthetic, hairless skin plaques; characterized by high cell-mediated immunity with a largely Th1-type immune response

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36
Q

Lactose fermenting enteric bacteria

A

Fermentation of lactose –> pink colonies on MacConkey agar
E.g. Klebsiella, E.coli, Enterobacter and Serratia (weak fermenter)
E.coli produces beta-galactosidase which breaks down lactose into glucose and galactose
-EMB agar - lactose fermenters grow as purple/black colonies. E.coli grows with a green sheen

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37
Q

Neisseria

A

Gram - diplococci
Metabolize glucose and produce IgA protease so
N.gonorrhoeae is often intracellular (within neutrophils)
MeningiGococci ferment Maltose and Glucose, while Gonococci ferment just Glucose

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38
Q

N.gonoccoci

A

No polysaccharide capsule
No maltose metabolized
No vaccine due to antigenic variation of pilus proteins
Sexually or perinatally transmitted
Causes gonorrhea, septic arthritis, neonatal conjunctivitis, pelvic inflammatory disease (PID), and Fitz-Hugh-Curtis syndrome
Prevention: Condoms decrease sexual transmission, erythromycin eye ointment prevents neonatal blindness
Treatment: ceftriaxone + azythromycin OR doxycycline for possible chlamydial coinfection

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39
Q

N.meningococci

A

Polysaccharide capsule
Maltose fermentation
Vaccine (type B vaccine not widely available)
Transmitted via respiratory and oral secretions
Causes meningococcemia with petechiae hemorrhages and gangrene of toes, meningitis, Waterhouse-Friderichsen syndrome (adrenal insufficiency, fever, DIC, shock)
Prevention: rifampin, ciprofloxacin, or ceftriaxone prophylaxis in close contacts
Treatment: ceftriaxone or penicillin G

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40
Q

Haemophilius influenzae

A

Small gram - (coccobacillary) rod, produces IgA protease. Culture on chocolate agar (factors V - NAD+ - and X - hematin) for growth (can be grown with S.aureus which provides factor V through hemolysis of RBCs)
Aerosol transmission
Nontypeable strains are the most common cause of mucosal infections (otitis media, conjunctivitis, bronchitis) as well as invasive infections since the vaccine for capsular type b was introduced
Causes Epiglotitis (endoscopic “cherry red” or “thumbprint sign” on XR), meningitis, Otitis media, Pneumonia
Treatment: amoxicillin +/- clavulante for mucosal infections; ceftriaxone for meningitis, rifampin prophylaxis for close contacts

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41
Q

H.influenzae vaccine

A

Contains type b capsular polysaccharide and PRP (polyribosylribitol phosphate) conjugated to diphtheria toxoid or other protein
Give between 2 and 18 months of age
Does not cause the flu (influenza virus)

42
Q

Bordetella pertussis

A

Gram - aerobic coccobacillus
VFs: pertussis toxin (disables Gi) and tracheal cytotoxin
Causes whooping cough
Prevented by Tdap, DTaP vaccines
May be mistaken as viral infection due to lymphocytic infiltrate from immune response

43
Q

Legionella pneumophila

A

Gram - rod. Gram stains poorly (use silver stain)
Grown on charcoal yeast extract medium with iron and cysteine
Detected by presence of Ag in urine
Labs may show hyponatremia
Aerosol transmission from environmental water source habitat (e.g. Air conditioning systems, hot water tanks) - no person to person
Treatment: macrolide or quinolone
Ligonnaires’ disease and Pontiac fever (mild-flu like symptoms)

44
Q

Legionnaires’ disease

A
Severe pneumonia (often unilateral and lobar), fever, GI and CNS symptoms 
Common in smokers and in chronic lung disease
*Think of a French legionnaire (soldier) with his silver helmet, sitting around a campfire (charcoal) with his iron dagger - he is no sissy (cysteine)*
45
Q

Pseudomonas aeruginosa

A

Gram - rod, aerobic, motile, non-lactose fermenting, oxidase +
Produces pyocyanin (blue-green pigment)
Has a grape-like odor
Produces exotoxin (fever, shock), exotoxin A (inactivates EF-2), phospholipase C (degrades cell membranes), and pyocyanin (generates ROS)
Mucoid polysaccharide capsule may contribute to chronic pneumonia in cystic fibrosis pts due to biofilm formation
Frequently found in water –> hot tub folliculitis

46
Q

Pseudomonas aeruginosa: Infections

A
*PSEUDOMONAS*
Pneumonia, Pyocyanin
Sepsis
Ecthyma gangrenosum - rapidly progressive, necrotic cutaneous lesion, cause by Pseudomonas bacteremia. Typically seen in immunocompromised pts
UTIs
Diabetes, Drug use
Osteomyelitis (e.g. Puncture wounds)
Mucoid polysaccharide capsule
Otitis Externa (swimmers ear)
Nosocomial infections (catheters, equipment
exotoxin A
Skin infections (hot tub folliculitis)
47
Q

Pseudomonas aeruginosa: Treatments

A

CAMPFIRE drugs
Carbapenems
Aminoglycosides
Monobactams
Polyhymnia (e.g. Polymyxin B, Colistin)
Fluoroquinolones (e.g. Ciprofloxacin and levofloxacin)
ThIRd- and fourth generation cephalosporins (ceftazidime, cefepime)
Extended-spectrum penicillins (piperacillin, ticarcillin)

48
Q

E.coli

A

Gram - rod
VFs: fimbriae (cystitis and pyelonephritis - P-pili); K capsule (pneumonia, neonatal meningitis); LPS endotoxin (septic shock)

49
Q

EIEC

A

Toxin & MOA: Microbe invades intestinal mucosa and causes necrosis and inflammation
Presentation: Invasive; dysentery.
Clinical: manifestations similar to Shigella

50
Q

ETEC

A

Toxin & MOA: Produces heat-labile and heat stable enteroToxins. No inflammation or invasion
Presentation: Traveler’s diarrhea (water)

51
Q

EPEC

A

Toxin & MOA: No toxin produced. Adheres to apical surface, flattens villi, prevents absorption
Presentation: diarrhea, usually in children (Pediatrics)

52
Q

EHEC

A

Toxin & MOA: O157:H7 is most common serotype in US. Often transmitted via undercooked meat, raw leafy vegetables
-Shiga-like toxin causes hemolytic-uremic syndrome (HUS): triad of anemia, thrombocytopenia, acute renal failure due to microthrombi forming on damaged endothelium –> mechanical hemolysis (schistocytes), platelet consumption, decreased renal blood flow
Presentation: dysentery (toxin alone causes necrosis and inflammation)
Does not ferment sorbitol (distinguishes from other strains of E.coli)

53
Q

Klebsiella

A

Gram - rod.
Intestinal flora that causes lobar pneumonia in alcoholics and diabetics when aspirated
Very mucoid colonies caused by abundant polysaccharide capsules
Dark red “currant jelly” sputum (blood/mucus)
Also cause of nosocomial UTIs
4 As of klebsiellA: Aspiration pneumonia, Abscess in lungs & liver, Alcoholics, di-A-betes

54
Q

Campylobacter jejuni

A

Gram -, comma or S shaped (with polar flagella), oxidase +, grows at 42 degrees C
Major cause of bloody diarrhea, esp in children
Fecal-oral transmission through person to person contact or via ingestion of undercooked contaminated poultry or meat, unpasteurized milk. Contact with infected animals (dogs, cats, pigs) is also a risk factor
Common antecedent to Guillain-Barré syndrome and reactive arthritis

55
Q

Salmonella typhi

A

Gram - rods, non-lactose fermenters, oxidase -, and can invade the GI tract via M cells of Peyer’s patches
Reservoirs: humans only
Spread: disseminate hematogenously
H2S production: YES
Flagella: Yes (salmon swim)
VFs: Endotoxin, Vi capsule
Infectious dose: high - large inoculum required because organism inactivated by gastric acids
Effect of antibiotics on fecal excretion: prolongs duration
Immune response: primarily monocytes
GI manifestations: constipation followed by diarrhea
Vaccine: Oral vaccine (live attenuated S.typhi), IM vaccine (Vi capsular polysaccharide)
Unique properties: causes typhoid fever (rose spots on abdomen, constipation, abdominal pain, fever); treat with ceftriaxone or fluoroquinolone; carrier state with gallbladder colonization

56
Q

Salmonella app. (Except S.typhi)

A

Gram - rod, non-lactose fermenters, oxidase -, and can invade the GI tract via M cells of Peyer patches
Reservoir: humans and animals
Spread: disseminate hematogenously
H2S production: Yes
Flagella: Yes (salmon swim)
VFs: Endotoxin
Infectious dose: high
Effect of antibiotics on fecal excretion: prolongs duration
Immune response: PMNs in disseminated disease
GI manifestations: diarrhea (possibly bloody)
Vaccine: none
Unique properties: poultry, eggs, pets, and turtles are common sources; antibiotics not indicated; gastroenteritis is usually caused by non-typhoidal Salmonella

57
Q

Shigella

A

Gram - rod, non-lactose fermenting, oxidase -, invades GI tract via M cells in Peyer patches
Reservoirs: humans only
Spread: cell to cell; no hematogenous spread
H2S production: No
Flagella: No
VFs: endotoxin, Shiga toxin (enterotoxin)
Infectious dose: low - very small inoculum required, resistant to gastric acids
Effect of Antibiotics on fecal excretion: shortens duration
Immune response: primarily PMN infiltration
GI manifestations: bloody diarrhea (bacillary dysentery)
Vaccine: none
Unique properties: Four F’s: Fingers, Flies, Flood, Feces, in order of decreasing severity (less toxin produced), S.dysenteriae, S.flexneri, S.boydii, S.sonnei; invasion is the key to pathogenicity - organisms that produce little toxin can cause disease due to invasion

58
Q

Vibrio cholerae

A

Gram -, flagellated, comma shaped, oxidase +, grows in alkaline media
Endemic to developing countries
Produces profuse rice-water diarrhea via enterotoxin that permanently activates Gs –> increased cAMP
Sensitive to stomach acid (acid labile); requires large inoculum (high ID) unless host has decreased gastric acidity. Prompt oral rehydration is necessary

59
Q

Yersinia enterocolitica

A

Gram - rod, usually transmitted from pet feces (eg puppies), contaminated milk or pork.
Cause acute diarrhea or pseudoappendicitis (right lower abdominal pain due to messenger if adenitis and/or ileitis)

60
Q

Helicobacter pylori

A

Curved, terminally flagellated, gram - rod that is triple + (catalase, oxidase and urease +) - can use urea breath test or fecal Ag test for diagnosis
Urease produces ammonia, creating an alkaline environment, which helps H.pylori survive in acidic mucosa
Colonizes mainly the Antrum of the stomach; causes gastritis and peptic ulcers (esp duodenal)
Risk factor for peptic ulcer disease, gastric adenocarcinoma, MALT lymphoma
Treatment: triple therapy = Amoxicillin (metronidazole if penicillin allergy) + Clarithromycin + PPI

61
Q

Spirochetes

A

Spiral shaped bacterial with axial filaments
Includes borrelia (big size), Leptospira and Treponema. Only Borrelia can be visualized using aniline dyes (Wright or Giemsa stain) in light microscopy due to size
Treponema is visualized by dark-field microscopy or direct fluorescent Ab (DFA) microscopy

62
Q

Leptospira interrogans

A

Spirochete found in water contaminated with animal urine, causes leptospirosis
Flu-like symptoms, myalgia (classically calves), jaundice, photophobia with conjunctival suffusion (erythema without exudate) - prevalent among surfers and in tropics (eg Hawaii

63
Q

Weil disease

A

Icterohemorrhagic leptospirosis - severe form with jaundice and azotemia from liver and kidney dysfunction, fever, hemorrhage, anemia

64
Q

Lyme disease

A

Borrelia burgodorferi (transmitted by the Ixodes deer tick - vector for Anaplasma spp. And Protozoa Babesia)
Natural reservoir is the mouse. Mice are important to the tick life cycle
Common in NE USA
Stage 1: early localized - erythema migrans (target symbol), flu-like symptoms
Stage 2: early disseminated - secondary lesions, carditis, AV block, facial nerve (Bell palsy), migratory myalgias/transient arthritis
Stage 3: late disseminated - encephalopathies, chronic arthritis

65
Q

Primary syphilis

A

Treponema pallidum
Localized disease presenting with painless chancre
If available use dark-field microscopy to visualize treponema in fluid from chancre
VDRL + (80%) of the time

66
Q

Secondary syphilis

A

Treponema pallidum
Disseminated disease with constitutional symptoms, maculopapular rash (including palms and soles), condylomata lata (smooth, moist, painless, wart-like white lesions on genitals), lymphadenopathy, patch hairs loss, also confirmable with dark-field microscopy.
Serologic testing: VDRL/RPR (nonspecific), confirm diagnosis with specific test (FTA-ABS)
Secondary syphilis = Systemic. Latent syphilis (+ serology without symptoms) may follow

67
Q

Tertiary Syphilis

A

Treponema pallidum
Gummas (chronic granulomas), aortitis (vasa vasorum destruction), neurosyphilis (tabes dorsalis, general paresis), Argyll Robertson pupil (constriction with accommodation but is not reactive to light)
Signs: broad-based ataxia, + Romberg, Charcot joint, stroke without HTN
For neurosyphilis: test spinal fluid with VDR1, FTA-ABS, PCR

68
Q

Congenital syphilis

A

Presents with facial abnormalities such as rhagades (linear scars at angle of mouth, snuffles (nasal discharge), saddle nose, notched (Hutchinson) tweet, mulberry molars, and short maxilla; saber shins; CN VIII deafness
To prevent, treat mother early in pregnancy; as placental transmission typically occurs after first trimester

69
Q

VDRL false positives

A

VDRL detects nonspecific Ab that reacts with beef cardio lipid
Inexpensive, widely available test for syphilis, quantitative, sensitive but not specific
Viral infections (eg EBV, hepatitis)
Drugs
Rheumatic fever
Lupus and Leprosy

70
Q

Jarisch-Herxheimer reaction

A

Flu-like syndrome (fever, chills, HA, myalgia) after antibiotics are started; due to killed bacteria (usually spirochetes) releasing toxins

71
Q

Zoonotic bacteria: anaplasma spp.

A

Disease: Anaplasmosis

Transmission/source: Ixodes ticks (live on deer and mice)

72
Q

Zoonotic bacteria: Bartonella spp.

A

Disease: Cat scratch disease, bacillary angiomatosis

Transmission/source: cat scratch

73
Q

Zoonotic bacteria: Borrelia burgodorferi

A

Disease: Lyme disease

Transmission/source: Ixodes ticks (live on deer and mice)

74
Q

Zoonotic bacteria: Borrelia recurrentis

A

Disease: relapsing fever

Transmission/source: Louse (recurrent due to variable surface Ag)

75
Q

Zoonotic bacteria: Brucella spp.

A

Disease: Brucellosis/undulant fever

Transmission/source: Unpasteurized dairy

76
Q

Zoonotic bacteria: Campylobacter

A

Disease: bloody diarrhea

Transmission/source: feces from infected pets/animals; contaminated meats/foods/hands

77
Q

Zoonotic bacteria: Chlamydophila psittaci

A

Disease: Psittacosis

Transmission/source: parrots and other birds

78
Q

Zoonotic bacteria: Coxiella burnetii

A

Disease: Q fever

Transmission/source: aerosols of cattle/sheep amniotic fluid

79
Q

Zoonotic bacteria: Ehrlichia chaffeensis

A

Disease: Ehrlichiosis

Transmission/source: Ambylomma (lone star tick)

80
Q

Zoonotic bacteria: Francisella tularensis

A

Disease: Tularemia

Transmission/source: ticks, rabbits, deer flies

81
Q

Zoonotic bacteria: Leptospira spp.

A

Disease: leptospirosis

Transmission/source: animal urine in water; recreational water use

82
Q

Zoonotic bacteria: Mycobacterium laprae

A

Disease: leprosy

Transmission/source: humans with lepromatous leprosy; armadillos (rare)

83
Q

Zoonotic bacteria: Pasteurella multocida

A

Disease: cellulitis, osteomyelitis

Transmission/source: animal bites, cats, dogs

84
Q

Zoonotic bacteria: Rickettsia prowazekii

A

Disease: epidemic typhus

Transmission/source: human to human via human body louse

85
Q

Zoonotic bacteria: rickettsia rickettsii

A

Disease: Rocky Mountain spotted fever

Transmission/source: dermacentor (dog tick)

86
Q

Zoonotic bacteria: Rickettsia typhi

A

Disease: Endemic typhus

Transmission/source: fleas

87
Q

Zoonotic bacteria: Samonella spp. (Except S.typhi)

A

Disease: diarrhea (which may be bloody), vomiting, fever, abdominal cramps
Transmission/source: reptiles and poultry

88
Q

Gardnerella vaginalis

A

A pleomorphic, gram variable rod involved in bacterial vaginosis
Presents as gray vaginal discharge with a fishy smell; nonpainful (vs. vaginitis)
Associated with sexual activity, but not sexually transmitted
Characterized by overgrowth of certain anaerobic bacteria in vagina
Clue cells (vaginal epithelial cells covered with gardnerella) have stipples appearance along outer margin
Treatment: metronidazole or clindamycin
Amine whiff test - mixing discharge with 10% KOH enhances fishy odor

89
Q

Rocky Mountain spotted fever

A

Rickettsia rickettsii (tick vector)
Occurs in south Atlantic states (esp NC)
Rash typically starts at wrists and ankles and spreads to trunk, palms and soles
Classic triad: HA, fever, rash (vasculitis)

90
Q

Typhus

A

R.typhi - endemic (fleas); R.prowazekii epidemic (human body louse)
Rash starts centrally and spreads out sparing palms and soles
rickettsii on the wRist, Typhi on the Trunk

91
Q

Ehrlichiosis

A

Ehrlichia, vector is tick

Monocytes with morulae (mulberry-like inclusions) in cytoplasm

92
Q

Anaplasmosis

A

Anaplasma (tick vector)
Granulocytes with morulae in cytoplasm
MEGA berry - Monocytes=Ehrlichiosis; Granulocytes=Anaplasmosis

93
Q

Q fever

A

Coxiella burnetii: no arthropod vector
Spores inhaled as aerosols from cattle/sheep amniotic fluid
Presents as pneumonia
Most common cause of culture - endocarditis
Q is for Queer because it has no rash or vector and its causative organism can survive outside in its endospore form

94
Q

Chalmydiae

A

Chlamydiae cannot make their own ATP. They are obligate intracellular organisms that cause mucosal infections
-Elementary body (small, dense) is “Enfectious” and Enters cell via Endocytosis; transforms into reticulate body
-Reticulate body Replicates in cell by fission; Reorganizes into elementary bodies
Treatment: Azithromycin (favored because of one time treatment) or Doxycylcine
Lab diagnosis: cytoplasmic inclusions seen on Giemsa or fluorescent Ab-stained smear

95
Q

Chlamydiae: types

A

The chlamydial cell wall lacks Classic peptidoglycan (due to reduced muramic acid) rendering beta lactam antibiotic less effective
Chlamydia trachomatis: reactive arthritis (Reiter syndrome), follicular conjunctivitis, nongonococcal urethritis and PID
Chlamydophila pneumoniae and chlamydophila psittaci: atypical pneumonia (transmitted by aerosol)
-psittaci: has an avian reservoir (parrot causes atypical pneumonia)

96
Q

Chlamydia trachomatis serotypes: A,B,C

A

Chronic infection, blindness due to follicular conjunctivitis in Africa
Africa, Blindness, Chronic infection

97
Q

Chlamydia trachomatis serotypes: D-K

A

Urethritis/PID, ectopic pregnancy, neonatal pneumonia (staccato cough) with eosinophilia, neonatal conjunctivitis

98
Q

Chlamydia trachomatis serotypes: Types L1, L2, L3

A

Lymphogranuloma venereum
Small painless ulcers on genitals –> swollen painful inguinal lymph nodes that ulcerate (buboes).
Treat with doxycycline

99
Q

Mycoplasma pneumoniae

A

Classic cause of atypical “walking” pneumonia (insidious onset, HA, nonproductive cough, patchy or diffuse interstitial infiltrate, more common in pts >30 y/o, common in military recruits and prison)
X-RAYS looks worse than pt. high hitter of cold agglutinins (IgM) which can agglutinate or lose RBCs
Grown on Eaton agar
Tx: macrolides, doxycycline, or fluoroquiniolone (penicillin ineffective since it has no cell wall on gram stain - pleomorphic)
Bacterial membrane contains sterols for stability

100
Q

Gram + cocci antibiotic tests: Staphylococci

A

Novobiocin - Saprophyticus is resistant; Epidermidis is Sensitive
on the office’s “Staph” retreat, there was NO StRESs