MICROBIOLOGY

Question 1

What is the difference b/w oral candidiasis and hairy leukoplakia?

Answer 1

both commonly found in immunocompromised individuals

oral candidiasis is a white deposit on the floor of the tongue that can be easily be scraped away

hairy leukoplakia is a white/gray deposit on the lateral surface of the tongue that cannot be easily scraped away

Question 2

What is the mechanism of action of the shiga toxin associated w/ shigella?

Answer 2

inhibits 60s subunit of ribosomes

Question 3

How does shigella infect cells?

Answer 3

induces phagocytosis by M cells
uses actin filaments to escape, then inducing apoptosis

Question 4

_____ is an anaerobic endospore-forming bacterium passed by fecal-oral contamination

Answer 4

C. difficile

Question 5

_____ a gram-negative, oxidase-negative bacteria that does not ferment sorbitol, is often acquired from undercooked meat and can cause bloody diarrhea and abdominal pain

Answer 5

E. coli

Question 6

A complication of infection with E coli is ____, characterized by thrombocytopenia and an elevated creatinine level.

Answer 6

hemolytic uremic syndrome

Question 7

______ is a non–lactose fermenting, oxidase-positive, comma-shaped, gram-negative organism.

Answer 7

Vibrio cholerae

Question 8

What is the key virulence factor of vibrio cholerae?

Answer 8

V cholerae secretes a toxin that irreversibly activates Gs, which in turn activates adenylyl cyclase and increases cAMP levels and overactivates protein kinase A. This leads to increased chloride excretion into the gastrointestinal lume

Question 9

Chronic gastric ulcers caused by H. pylori manifest as ______ on histology

Answer 9

punched-out lesions with scar tissue and chronic inflammatory cells in biopsy specimens

Question 10

_____ is a double-stranded, linear-segmented RNA virus and a common cause of viral gastroenteritis

Answer 10

rotavirus

Question 11

______ is a Double-stranded, nonenveloped DNA virus

Answer 11

adenovirus