Microbiology

Question 1

Vibrio Cholerae Transmission

Answer 1

Contaminated water; Undercooked seafood (raw shellfish)

** Fecal oral transmission

Question 2

Characteristics of Vibrio Cholerae

Answer 2

1) Curved (comma shaped)
2) Polar Flagella
3) Grows in alkaline media –> acid labile –> Large infectious dose
4) Oxidase Positive

Question 3

Virulence Factor of Vibrio Cholerae

Answer 3

Cholera Toxin (enterotoxin)

Question 4

Characteristic Diarrhea

Answer 4

Rice Water Diarrhea

Question 5

Vibrio Cholerae Treatment

Answer 5

Fluoroquinolones and Oral rehydration w/ electrolytes

Question 6

Diagnosis of Vibrio Cholerae

Answer 6

Dipstick (rapid initial test)

Stool culture = confirmatory

Question 7

Vibrio Cholerae MOA

Answer 7

1) Fimbriae attaches to ganglioside receptors in intestinal wall then secretes cholera toxin
2) Increased cAMP via Gs pathway –> Increased Cl- secretion into lumen via CFTR

Question 8

Campylobacter Jejuni Reservoir

Answer 8

1) Poultry, unpasteurized milk

2) Contact with infected persons or infected animal

Question 9

Characteristics of Campylobacter Jejuni

Answer 9

1) Curved gram - rod w/ polar flagellum
2) Grows in heat
3) Oxidase +

Question 10

Virulence Factor Campylobacter Jejuni

Answer 10

1) Motility
2) Adherence
3) Toxin Production (Cytolethal distending toxin)
4) Invasion (Dysentery)

Question 11

Diseases Caused by Campylobacter Jejuni

Answer 11

1) Enterocolitis (Bloody diarrhea due to invasion)
2) Enteric Fever
3) Reactive Arthritis
4) Guillain-Barre Syndrome
5) Erythema Nodosum

Question 12

Describe Enteric Fever

Answer 12

Systemic infection associated with abdominal pain and fever

Question 13

HLA B27 is associated with arthritis, conjunctivitis, and urethritis. This is known as ….

Answer 13

1) Reactive Arthritis

Question 14

Which bacteria are associated with Reactive Arthritis

Answer 14

1) Shigella
2) Yersinia
3) Salmonella
4) Campylobacter
5) Chlamydia

Question 15

Guillain-Barre Syndrome is commonly seen in ____ infection.

Answer 15

Campylobacter Jejuni

Question 16

Describe Guillain-Barre Syndrome

Answer 16

Ascending Paralysis that starts are hands and feet

• absent or depressed deep tendon reflexes
• severe respiratory weakness

Question 17

Treatment for Guillain-Barre Syndrome

Answer 17

1) Plasma Exchange

2) IVIG

Question 18

Antibiotic for Camp. Jejuni

Answer 18

Macrolides (Erythromycin)

Question 19

Reservoir for Shigella

Answer 19

Humans

Question 20

Characteristics of Shigella

Answer 20

1) M Cell invasion via phagocytosis and evades phagolysosome
2) Uses host cell’s actin cytoskeleton to propel from cell to cell
3) resistant to Gastric Acid –> Low infectious dose

Question 21

Virulence of Shigella

Answer 21

Shiga Toxin (Exotoxin)

Question 22

MOA of Shiga Toxin

Answer 22

Inhibits 60 ribosome via cleavage of adenine in rRNA

Question 23

Disease caused by Shigella

Answer 23

1) Shigellosis (Watery Diarrhea –> Bloody Diarrhea) and Enteric Fever
2) Reactive Arthritis
3) HUS (Hemolytic-Uremic Syndrome) due to Shiga Toxin
4) Toxic Megacolon

Question 24

Shigella Treatment

Answer 24

1) Fluoroquinolones (Ciprofloxacin)
2) 3rd generation Cephalosporin (Ceftriaxone)

*Antidiarrheal prolong disease

Question 25

Salmonella Non-Typhoidal Reservoir

Answer 25

1) Animals | 2) Products (reptiles, poultry, pets, eggs)

Question 26

Salmonella Non-Typhoidal Characteristics

Answer 26

1) Acid Labile 2) H2S (all motile enteric bacteria) - Black colonies on nectar agar plate 3) Encapsulated

Question 27

Virulence of Salmonella Non-typhoidal

Answer 27

Flagellar Motility and Endotoxin (Lipopolysaccharide)

Question 28

Disease of Salmonella Non-Typhoidal

Answer 28

Salmonellosis (Gastroenteritis and Food Poisoning) | - Watery-bloody diarrhea, fever, chills, myalgia, and severe vomiting

Question 29

Salmonellosis typically effect what GI sites

Answer 29

1) Colon | 2) Small Intestines

Question 30

Shigellosis causes bloody diarrhea and commonly affects ___ and ___.

Answer 30

1) Left Colon | 2) Ileum

Question 31

Enteric (Typhoid) Fever Affects which area of the GI

Answer 31

Small Intestines

Question 32

Complication that is associated with Salmonellosis

Answer 32

1) Sepsis | 2) Abscess

Question 33

Population Salmonella Non-Typhoidal

Answer 33

Young Children and Older Adults (Summer and Fall)

Question 34

Salmonella Typhi and Paratyphoid Reservoir

Answer 34

Humans

Question 35

Characteristics of Salmonella Typhi and Paratyphi

Answer 35

1) Highly infectious dose required --> not resistant against gastric acid 2) Hematogenous dissemination is possible 3) Produces H2S 4) Immune response primarily via monocytes

Question 36

Virulence of Salmonella Typhi and Paratyphi

Answer 36

1) Flagellar Motility 2) Vi Capsule: - Evasion of neutrophil phagocytosis - Inhibits complement activates

Question 37

Disease caused by Salmonella Typhi

Answer 37

1) Typhoid Fever and Paratyphoid Fever (Enteric Fever) - rose colored macules: Erythematous maculopapular rash - bloody diarrhea followed by short asymptomatic phase --> bacteremia and fever w/ flu like symptoms