diagnosis

Question 1

S. pyogenes

Answer 1

pharyngitis diagnosis by throat swab: Strep A antigen test, growth on blood agar

Question 2

S. pneumoniae

Answer 2

gram stain of sterile tissue, fluid sample, urine antigen test for C-polysaccharide

Question 3

B. anthracis

Answer 3

gram stain, endospore stain, colony morphology, capsule prescence, chest X-ray, CT scan

Question 4

B. cereus

Answer 4

isolation of organism from food source using bacara media, gram stain, endospore stain, chemical testing

Question 5

L. pneumophila

Answer 5

urine antigen test and/or culture of sputum on buffered charcoal yeast extract, GEMSA stain

Question 6

L. monocytogenes

Answer 6

gram stain of CSF, culture of CSF or blood

Question 7

M. tuberculosis

Answer 7

culture/microscopy of sputum on Lowenstein-Jensen or Middlebrook 7H11, tuberculin skin test (Mantoux test), Chest X ray, nucleic acid amplification

Question 8

C. diphtheriae

Answer 8

based on characteristic pseudomembrane, microscopy is NOT effective, can be cultured from samples on blood agar, colitistin nalidixic acid agar

Question 9

B. pertussis

Answer 9

nasopharyngeal swab onto Bordet-Gengou media or Regan-Lowe media, serotesting

Question 10

S. aureus

Answer 10

gram stain of pus, selective media culture (MSA), coagulase test

Question 11

E. coli

Answer 11

growth on selective media, physiological tests, serotyping, nucleic acid testing; UPEC: clean catch urine on BAP (B hemolysis), Mac (lac +)

Question 12

Shigella spp.

Answer 12

growth on selective media, physiological tests, serotyping, nucleic acid testing

Question 13

S. enterica spp. enterica

Answer 13

stool (all) or blood (Typhi) plated on MacConkey , suspect colonies on TSI, Gruber-Widal test for antigenic analysis to confirm serotype - Typhi culture must be chosen carefully (blood week 1, stool 2/3)

Question 14

Y. pestis

Answer 14

clinical suspicion, GEMSA stain of blood, sputum, buboe aspirate (safety pin staining)

Question 15

C. perfringens

Answer 15

Nagler reaction - one 1 side, patient sample and antitoxin (if C. perf no clearing) one side patient sample (should be opaque zone around streak caused by alpha toxin)

Question 16

C. tetani

Answer 16

clinical suspicion, microscopic detection

Question 17

C. botulinum

Answer 17

clincial presentation, detection of toxin, infant - culture of gastric aspirate on TSC

Question 18

C. difficile

Answer 18

detection of toxin by immunoassay or nucleic acid test, culture of stool on CCFA agar

Question 19

N. gonorrheae

Answer 19

immediate culture onto prewarmed Thayer-Martin or Martin-Lewis media, and chocolate agar w/ moisture, 5% CO2

Question 20

N. meningitidis

Answer 20

microscopy of CSF, transparent/non-pigmented, nonhemolytic colonies on chocolat eagar

Question 21

T. pallidum

Answer 21

serological testing - VDRL: venereal disease research laboratory test (based on cardiolipin prescence in blood), FTA-ABS: fluroescent treponemal antibody absorption test; best for primary syphilis is dark-field microscopy of sample from lesion (chancre)

Question 22

influenza

Answer 22

clinical presentation, nasopharyngeal swab or sputum testing (viral antigen or RT-PCR), hemagglutination of RBCs

Question 23

measles

Answer 23

clinical presentation, antigen or genome detected in urinary sediment or pharyngeal cells