CASE STUDY B Case Studies Set 1pdf rying more than 500 passe

CASE STUDY B Case Studies Set 1.pdf rying more than 500 passengers departed a port bound for the car bbean. Two days after departure an gastroenterstis occurred over the next days affect ng y 125 passengers e symptoms reported included vomiting bloody diarrhea and abdominal oramps was also reported by a relatively anall fraction of the att passengers. The median incubation tine for this illness was about S sually to 2 day f 20 of the sack passengera the next day for suspicious colonie found on MacConkey agar and a blood agar plate econd MacConkey agar plate and the blood agar plate ahorald be from the blood agar plate are a 30 gram stain. I4 3 AND 4 E. 2 AND 4 of the following which would be the next, most appropriate lab test causing this outbreak of gastroente atitia? The lab procedure es selected should be based on your analysis of the appearance of the oolonies on the blood and MacConkey agar plates the gram stain results cell morphology and

Solution

Answer:

Based on the given information:

Nausea, bloody diarrhea and abdominal cramps and fever in a small fraction

Median incubation time: 5hrs

Symptoms usually subsided after 12 hrs and in some cases persisted up to 2days

Sub cultured to Secondary MacConkey agar and a blood agar plate:

1. The second MacConkey agar plate and the blood agar plate should be incubated

Ans: A) Aerobically at 37°C

2. The most useful lab tests that should be done next using colonies from the blood agar plate are 1) oxidase test 2) catalase test 3) gram stain 4) coagulase test

Ans: A) 1 and 2 (oxidase test and catalase test)

3. Of the following, which would be the next, most appropriate lab test for identifying the bacterium causing this outbreak of gastroenteritis? The lab procedure selected should be based on your analysis of the appearance of the colonies on the blood and MacConkey agar plates, the gram strain results (cell morphology and arrangement), and the oxidase test.

Ans: TSI slant