Blog

Match the organism with the gram-stain reaction and morphology

A sputum sample submitted for Mycobacterium culture grew numerous orange-colored colonies that stained acid-fast after three weeks of incubation in 37° C in the dark.  These characteristics are consistent with identification of this isolate as a:

The organism shown in this gram stained smear was isolated from a wound infection.  It was catalase positive and coagulase negative. Of the following, what is the likely agent? G+C Exam.jpg

A 53 year old patient presented to the physician with manifestations characterized as chronic arthritis of the large joints. Synovial fluid is exudative, however, rheumatoid factor is not detected. The patient gave a history of spending his summer vacation with his parents in Wisconsin  where he spent time picking blackberries. He recalled being bitten by some type of “insect” that produced a small erythematous lesion that had a bullseye appearances. The lesion disappeared within a few weeks. Based on this history, the physician should suspect which of the following conditions?

Illustrated in this picture is an organism from a diarrheal stool specimen that was plated onto thiosulfate citrate bile sucrose (TCBS) agar.  Other test results include O129 vibriostatic agent= susceptible 0% NaCl broth= growth 3% NaCl broth- growth 8% NaCl broth- no growth Of the following, the most likely organism is: TCBS sucrose +.png

In the Kirby-Bauer disk diffusion test, if the plates used for the antibiotic susceptibility test are thinner than the recommended thickness of 3 – 5 mm, the zone diameter will show which of the following after proper incubation?

The urine from a 70 year old patient yields Gram positive cocci. Additional findings are shown below: SBA and CNA agar: small, gray, non-hemolytic colonies MacConkey: No growth Catalase: Negative PYR: Negative 6.5% NaCL: Negative Bile Esculin hydrolysis: Positive Which of the following is the most likely isolate?

A 35 year old pregnant femalewith fever, chills nausea and vomiting is admitted to the hospital. On further examination, the patient seemed incoherent and confused. CSF and blood cultures are taken and sent to the laboratory for examination.  Gram stained findings on the CSF showed gram positive non-spore forming rods. The colonies produced a narrow zone of beta hemolysis on sheep blood agar; catalase was produced. Based on these findings, you would suspect:

A gram positive coccus isolated from a urine of a 20 year old female grew on a blood agar plate as a non-hemolytic, white, creamy colony.  Additional testing showed the organism to be catalase positive and coagulase negative.  An additional test needed to identify the most likely species of this isolate is susceptibility to:

You received abscess fluid from the pulmonary cavity of a 58 year old woman patient. A Ziel-Neelson and a Gram stained smear are shown below. The culture grew colonies on the aerobic sheep blood agar after 5 days producing dry, wrinkled colonies with an orange/brown pigment. Based on the information in this question, which of the following is the suspected agent? stained smear(1).jpg gram stain smear.jpg