GRAM NEGATIVE

Question 1

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

Answer 1

EHEC (E. coli 0157:H7)

-HUS is characterized by ACUTE RENAL FAILURE, microangiopathic HEMOLYTIC ANEMIA, and THROMBOCYTOPENIA in children

Question 2

Leading cause of UTI’s

Answer 2

Escherichia coli

-other causes of UTIs include PROTEUS, SERRATIA, KLEBSIELLA, PSEUDOMONAS, and STAPHYLOCOCCUS SAPROPHYTICUS

Question 3

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

Answer 3

Escherichia coli

-the enterotoxigenic strain produces a HEAT STABLE and HEAT LABILE TOXIN that causes an EXPLOSIVE WATERY DIARRHEA with cramping, abdominal discomfort, and dehydration

Question 4

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

Answer 4

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, and liver

Question 5

Organism closely associated with chronic gastritis and peptic ulcer disease

Answer 5

Helicobacter pylori

-also associated with an increase in the development of GASTRIC CARCINOMA and MALToma

Question 6

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

Answer 6

Haemophilus influenzae

-vaccine is composed of the capsular material, POLYRIBITIOL PHOSPHATE [PRP] , conjugated to diphtheria toxin

Question 7

Major cause of aspiration pneumonia in alcoholics

Answer 7

Klebisella pneumoniae

-organism produces a large antiphagocytic capsule, giving it a MUCOID appearance and producing a thick, bloody, “CURRANT-JELLY” sputum

Question 8

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

Answer 8

Neisseria gonorrhoeae

-differentiated from N. meningitidis based on its ability to ferment GLUCOSE AND MALTOSE, whereas N. gonorrhoeae ferments GLUCOSE ONLY

Question 9

Leading cause of septic arthritis

Answer 9

Neisseria gonorrhoeae

-typically presents as MONOARTICULAR ARTHRITIS of the knee, ankle, or wrist after a bout of URETHRITIS

Question 10

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

Answer 10

Neisseria gonorrhoeae

-babies born in the US receive a required administration of tetracycline, erythromycin, or SILVER NITRATE DROPS to prevent this

Question 11

STD that can lead to PID that the predisposes to ectopic pregnancy

Answer 11

Neisseria gonorrhoeae

-2nd most common NOTIFIABLE DISEASE in the US

Question 12

Leading cause of meningitis among military recruits and dormitory settings

Answer 12

Neisseria meningitidis

-patients with DEFICIENCIES IN THE COMPLEMENT COMPONENTS C6-9, “THE MEMBRANE ATTACK COMPLEX” are particularly SUSCEPTIBLE TO INFECTION

Question 13

Septicemia resulting from this organism can result in progressive hypotension, DIC, widespread vascular purpura, and bilateral adrenal hemorrhage

Answer 13

Neisseria meningitidis

-the shock and ADRENOCORTICAL INSUFFICIENCY of WATERHOUSE-FRIDERICHSEN SYNDROME is RAPIDLY FATAL without Abx treatment

Question 14

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

Answer 14

Salmonella enteritidis

-this HIGHLY MOTILE organism requires a LARGE INFECTIOUS DOSE, which distinguishes it from Shigella spp.

Question 15

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

Answer 15

Salmonella typhi

-after recovery, a small percentage of pts may become carriers because the organisms COLONIZE THE GALLBLADDER, a state that may require CHOLECYSTECTOMY

Question 16

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

Answer 16

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

Question 17

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

Answer 17

Vibrio cholerae

-these COMMA SHAPED rods with a polar flagellum adhere to the intestinal mucosa and elaborate an exotoxin, but never invade

Question 18

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

Answer 18

Yersinia pestis

-transmission is also possible between humans in the case of the PNEUMONIC PLAGUE

Question 19

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

Answer 19

Yersinia pestis

-this organism displays BIPOLAR STAINING resulting in a SAFETY PIN APPEARANCE

Question 20

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

Answer 20

Bartonella henselae

-this is the causative agent of CAT SCRATCH DISEASE; infection of an immunocompromised pt can result in BACILLARY ANGIOMATOSIS, CRANBERRY-LIKE PUSTULES resembling Kaposi sarcoma

Question 21

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

Answer 21

EHEC (E. coli 0157:H7)

-this DYSENTERY-LIKE condition is due to the elaboration of VEROTOXINS similar to Shiga toxin that causes CYTOTOXICITY to the colonic mucosa

Question 22

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

Answer 22

Brucella spp.

-this GRANULOMATOUS INFECTION invades the RETICULO-ENDOTHELIAL CELLS of the lymph nodes, liver, spleen, and bone marrow

Question 23

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

Answer 23

Pasteurella multocida

-short, encapsulated, bipolar staining organism is part of the NASOPHARYNGEAL FLORA of domestic DOGS and CATS

Question 24

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

Answer 24

Haemophilus influenzae

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

Question 25

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

Answer 25

Campylobacter jejuni

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

Question 26

Predominant organism in the human colon

Answer 26

Bacteroides fragilis

-most often the cause of serious ANAEROBIC infection

Question 27

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

Answer 27

Calymmatobacterium granulomatis

-diagnosis is based on finding intracellular organisms aggregated as “DONOVANI BODIES”

Question 28

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

Answer 28

Serratia marcescens

-causes pneumonia, bacteremia, endocarditis, and is often MULTIDRUG-RESISTANT

Question 29

A STD, results in painful necrotizing genital ulcers (Chanchroid)

Answer 29

Haemophilus ducreyi

-infection in the US is rare, most infections occur in the TROPICS; painless ulcer= T. pallidum

Question 30

Infection can result in folliculitis, swimmers ear, pneumonia, and sepsis with the development of characteristic skin lesions (Ecthyma gangrenosum)

Answer 30

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

Question 31

Major cause of pneumonia in burn patients and cystic fibrosis patients

Answer 31

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

Question 32

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

Answer 32

Proteus spp. (P. mirabilis and P. vulgaris)

-these HIGHLY-MOTILE organisms are often refractory to Abx treatment because they often become trapped within stones

Question 33

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

Answer 33

Vibrio parahaemolyticus

-although this FREE-LIVING salt bacteria is related to V. cholerae, the symptoms are much milder

Question 34

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

Answer 34

Bordetella pertusis

-the vaccine includes the purified virulence factors FILAMENTOUS HEMAGGLUTININ (FHA) and PERTUSIS 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