Question

Several people from a picnic came down with a gastrointestinal disturbance, and public health officials suspected a case of food poisoning. The food was cultured, and after 24 hours of incubation, the hot dogs yielded growth on SBA of small, round, smooth, translucent colonies surrounded by a narrow zone of b-hemolysis. A Gram stain showed gram-positive coccobacilli. Motility medium was inoculated and an umbrella pattern of motility was observed at room temperature. What organism was isolated as the cause of the illness?

Answer 1

Listeria Monocytogenes.

Step-by-step explanation:

• Listeria Monocytogenes forms small, round, smooth, translucent colonies surrounded by a narrow zone of b-hemolysis.

• They are gram positive coccobacilii occuring in chains in gram-staining.
• They have a characteristic motility called tumbling motility at 25 degrees celsius and are non-motile at room temprature 37 degrees.
• It causes listeriosis, a serious infection by eating the food contaminated with the bacteria Listeria Monoctogenes, has recently been recognized us an important public health problem in the united states. This disease affects primarily the persons of advanced age, pregnant women, new-borns, and adults with weakened immune system.

Hence the best possible infection in this case is Listeria Monocytogenes.