Examination of a throat culture from a 9-year old female wit…

Examination of a throat culture from a 9-year old female with a “scratchy throat” reveals the following: moderate growth of small, alpha-hemolytic colonies; light growth of opaque, white, nonhemolytic colonies; and tiny, translucent colonies within a large zone of beta hemolysis on sheep blood agar.  You conclude:

Soft cheese imported from Mexico was implicated as the sourc…

Soft cheese imported from Mexico was implicated as the source in an outbreak of meningitis that occurred among attendees of a large company picnic. Gram-positive, nonspore forming, motile, coccobacilli were isolated from the cheese that had been stored in the cold. The organism most likely responsible for this outbreak is:

The following results were obtained when an ampicillin micro…

The following results were obtained when an ampicillin microdilution test was performed: Test Well Result Sterility Turbid Growth Turbid 1 µg/mL Turbid 2 µg/mL Turbid 4 µg/mL Turbid 8 µg/mL Turbid 16 µg/mL Turbid 32 µg/mL Turbid   An evaluation of these results indicates that the: