A pregnant patient is screen for Group B Streptococcus (GBS) at 36 weeks gestation. A vaginal swab is collected and cultured in Todd-Hewett broth with antibiotics. The broth is subcultured to a BAP after 24 hours of incubation. No GBS are seen on the subculture and the results are reported as negative. The patient later delivers an infant with early onset GBS disease. What is the most likely reason for the negative GBS culture?

Which of the following organisms does not require susceptibility testing to the antimicrobial indicated when isolated from a clinically significant source?

Gram stain examination from a blood culture bottle shows dark blue, spherical organisms in clusters. Growth on BAP shows small, round, yellow to cream colonies. Further testing should include:

Which organism is the causative agent of the bubonic plague?

What color do gram positive organisms appear on a gram stain?

The following is seen on a gram stain made from a blood culture bottle. How should this gram stain be reported?   image001638f805d.jpg

Which of the following is NOT considered normal skin flora?

In the previous month, Staphylococcus epidermidis has been isolated from blood cultures 3 times more frequently than the rate in the previous year. What is the most logical explanation for this occurrence?

A light yellow colony from a skin lesion grew aerobically and tested as catalase positive and coagulase negative. The gram stain showed gram positive cocci in clusters and was modified oxidase positive, bacitracin susceptible. What is the most likely identification of this organism?

All of the following are ways to identify viruses EXCEPT: