Exam 18: Enterobacteriaceae

An organism that appears red with a black center on XLD agar is lactose-_____ and H₂S-_____.

A green colony with a black center is isolated on HE agar from a stool specimen.It is most likely which organism?

E.coli would appear what color on HE agar?

Which is correct for the description "alkaline slant,acid butt,no H₂S"?

Of the following bacterial species,which is associated with a serious diarrheal illness with high mortality rates among some populations?

On MacConkey agar,Serratia spp.would appear:

MacConkey-sorbitol agar is useful for detecting pathogenic strains of:

If an organism were a glucose and lactose fermenter,the LIA reaction would be:

This organism,belonging to the family Enterobacteriaceae,grows best at 25°C to 30°C.Domestic and wild rats and other animals can carry this organism.What is the medium of choice?

In addition to being a group of gram-negative bacteria considered normal flora of the gastrointestinal tract of humans and animals,which one of the following also contains agents of important diseases such as gastroenteritis and enteric fevers,urinary tract infections,and bacterial pneumonia?

The major etiologic agent of urinary tract infections is:

A gram-negative bacillus that is hydrogen sulfide (H₂S)-positive,citrate-positive,spot indole-negative,and associated with gastroenteritis in the United States is most likely:

For the most part,all Enterobacteriaceae are positive for which biochemical reactions?

A patient bitten by a flea developed a painful bubo at the site of the bite.The drug of choice for this organism is:

Which of correct for the description "acid slant,acid butt,no H₂S"?

The swarming gram-negative bacillus that can be presumptively identified on the basis of a positive indole test is:

E.coli can produce a toxin similar to S.dysenteriae and can cause hemorrhagic colitis.What other organ does it affect?

Most strains of Escherichia coli can be presumptively identified on the basis of which characteristic?

Enterotoxigenic and enteroinvasive are terms often linked to which of the following bacterial species?

A green colony with a black center was isolated and presumptively identified as a Salmonella spp.The organism was serotyped with polyvalent antisera;however,the antisera tested negative for all antigens.What is the next course of action?