CSI261

Which of the following antigens is located in the cell wall of enteric bacteria?

• O antigen

• H antigen

• K antigen

• F antigen

Which strain of Escherichia coli primarily affects infants and children and causes outbreaks in hospital nurseries and day care centers?

• Enteroinvasive (EIEC)

• Enterohemorrhagic (EHEC)

• Enteropathogenic (EPEC)

• Enterotoxigenic (ETEC)

A 43-year-old male was seen in the ER and admitted to the ICU. He had positive urine and blood cultures with the same organism which was a gram-negative rod that grew on TSA (BAP) and MAC. It was a lactose fermenter on MAC and looked like E coli, however, it was indole negative.

Other biochemical testing was as follows:

MR positive and VP negative

Urease positive

Citrate positive (it grew on Simmons citrate agar)

H2S positive

• Escherichia coli

• Enterobacter aerogenes

• Klebsiella pneumoniae

• Citrobacter freundii

Which organism is an opportunistic pathogen that causes wound and urinary tract infections and may cause the production of kidney stones?

• Yersinia enterocolitica

• Citrobacter freundii

• Proteus mirabilis

• Enterobacter cloacea

What is a distinctive characteristic of Proteus species colonies?

• They are flat and smooth.

• They produce a yellow pigment.

• They swarm on non-selective media.

• They are motile.

A male older adult, hospitalized and recovering from cardiac bypass surgery, develops pneumonia. Sputum culture reveals a gram-negative rod that produces a green pigment but does not ferment carbohydrates. The most likely organism is:

• Klebsiella pneumoniae

• Proteus species

• Enterobacter species

• Pseudomonas aeruginosa

What type of colonies does Salmonella produce on differential selective agar?

• Pink, lactose fermenting colonies.

• Clear, colorless, lactose fermenting colonies

• Clear, colorless, non-lactose fermenting with H2S

• Green, non-lactose fermenting colonies

Which group of Shigella species does Shigella dysenteriae belong to?

• Group A

• Group B

• Group C

• Group D

Which pigment is produced by Serratia marcescens?

• Pyocyanin

• Prodigiosin

• Melanin

• Erytromycin

Which of the following characteristics is TRUE about Edwardsiella tarda?

• It ferments sucrose rapidly.

• It is indole-negative.

• Its produces hydrogen sulfide.

• It grows well on Simmons citrate.