Microbiology

Question 1

Which bacterial factors increase bacterial success rate?

Answer 1

High growth rate, dispersal capability, phenotype plasticity, genetic diversity

Question 2

Define colonization.

Answer 2

Establishment of a microorganism in a host

Question 3

Describe how MALDI-TOF differentiates pathogens.

Answer 3

Compares protein content of the cell wall to a database.

Question 4

Which GI pathogens is MALDI-TOF not good for?

Answer 4

E. coli, salmonella

Question 5

Which agars can be used to grow enterobacteria?

Answer 5

Blood, MacConkey, CLED, chromogenic

Question 6

C. diff has two different toxins. Name them.

Answer 6

A -> enterotoxin, B -> cytotoxin

Question 7

How does C. diff infect patients?

Answer 7

Antibiotics that kill off natural bacteria, allowing overgrowth. Transmissable by spores

Question 8

How does a C. diff infection present?

Answer 8

Diarrhoea, abdo pain, pseudomembranous colitis

Question 9

Which antibiotics are used to treat C. diff?

Answer 9

Less severe -> metronidazole, severe -> vancomycin

Question 10

Describe rotavirus.

Answer 10

Most common D&V cause in children < 3.
Diarrhoea with no blood, dehydration.
Rehydration is key, diagnosed with PCR
Vaccine given at 2 & 3 months

Question 11

Describe norovirus.

Answer 11

Affects all ages, explosive D&V
Rehydration is key
PCR from faeces and vomit

Question 12

When are patients most infectious?

Answer 12

With diarrhoea

Question 13

Define diarrhoea.

Answer 13

> 3 unformed stools in 24 hrs

Question 14

What is dysentry? Give the main symptoms.

Answer 14

Inflammation of the intestine. Diarrhoea with blood/mucus, fever, abdo pain, tenesmus

Question 15

Excluding E. coli, what are the six main bacteria from food?

Answer 15

Bacillus cereus, staph aureus, scombroid, campylobacter, salmonella, listeria

Question 16

What are the three main tests for bacteria from food?

Answer 16

Molecular testing, stool sample, PCR

Question 17

What does Shigella cause? What are the four types?

Answer 17

Dysentry, A/dysenteriae, B/flexneri, C/boydii, D/sonnei

Question 18

Describe the pathology of Shigella.

Answer 18

Shiga toxin binds to renal cells/RBCs/others to inhibit protein synthesis.

Question 19

Name the four main types of E. coli.

Answer 19

Enterotoxigenic, enteropathogenic, enteroinvasive, enteroaggregative

Question 20

What are the main symptoms of E. coli infection?

Answer 20

Abdo pain, fever, pallor, bloody diarrhoea

Question 21

Name the three main fevers suspected in travellers.

Answer 21

Acute travellers diarrhoea, enteric fever, amoebiasis

Question 22

What are the symptoms of giardiasis in travellers?

Answer 22

Watery diarrhoea, bloating, flatulence, abdo cramps, weight loss

Question 23

How are helminth infections diagnosed? What are the two main types?

Answer 23

Eosinophillia, eggs in faeces

Schistosomiasis/Chagas disease