Microbiology Flashcards

1
Q

Pathogenic infection sequence (6)

A

Exposure => Adhesion => Invasion => Colonization => Toxicity => Tissue damage and disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Enterobacteriaceae characteristics (4)

A

Gram negative
Non spore forming
Grows on variety of solid media
Ferments sugars producing acid - Facultative anaerobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Anaerobes in GI tract (3)

A

Clostridium sp
Bacteroides sp
Anaerobic cocci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Normal flora in mouth (5)

A
Strep viridans
Neisseria sp
Anaerobes
Candida sp - Few
Staphylococci
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Normal flora in stomach/duodenum (2)

A

Usually sterile

Few Candida sp and Staphylococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Normal flora in jejunum (2)

A

Coliforms and Anaerobes - Few

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Normal flora in colon (3)

A

Coliforms
Anaerobes
Enterococcus faecalis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Normal flora in bile ducts

A

Usually sterile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Clostridium difficile features (4)

A

Gram positive bacillus
Common cause of healthcare-associated diarrhoea
Carried as part of normal bacterial flora in elderly and infants
Produces 2 toxins; toxin A (Enterotoxin) and toxin B (Cytotoxin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Clostridium difficile source (2)

A

When antibiotics are prescribed bowel flora is killed off allowing C diff overgrow
C diff produces spores that survive in environment that are more resistant to disinfectants - Can be transmitted from one patient to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Clostridium difficile symptoms (4)

A

Diarrhoea +/- blood
Abdominal pain
Severe case - Pseudomembranous colitis, perforation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Clostridium difficile management (2)

A

Less severe - Oral metronidazole

More severe - Oral vancomycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Clostridium difficile prevention (4)

A

Use narrow spectrum antibiotics
Avoid 4C’s as much as possible
Patient isolation
Hand washing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Clostridium difficile investigations (3)

A

Screen for glutamate dehydrogenase (GDH)
If GDH positive then test for toxin A and B
Culture to type strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Rotavirus features (7)

A

Most common cause of diarrhoea and vomiting in children (Less than 3)
Person to person spread - Faecal -oral route
More common in winter months
Mild to severe diarrhoea but NO blood
Self limiting - 1 week duration
Decrease fluid absorption, increasing bowel secretion - Dehydration
Children may develop post-infection malabsorption causing more diarrhoea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Rotavirus diagnosis

A

PCR test on faeces

17
Q

Rotavirus management (2)

A
Oral rehydration (Mild to moderate)
Oral vaccine - Live attenuated vaccine, 2 doses age 2 and 3 months
18
Q

Norovirus features (4)

A

Winter vomiting disease - Now all year round
Faecal-oral spread - Person to person or on contaminated food/water
Environmental survival for days/weeks
Low infectious dose required - Short incubation

19
Q

Norovirus symptoms (2)

A

Sudden and explosive vomiting, diarrhoea

Vomiting leads to outbreaks - Hospitals, schools, cruise ships

20
Q

Norovirus diagnosis

A

PCR test on vomit swap or faecal specimen

21
Q

Norovirus management

A

Rehydration

Patient isolation

22
Q

Norovirus vital asymptomatic point

A

Asymptomatic shedding occurs for up to 48 hours post cessation of symptoms

23
Q

Action of shigella toxin (2)

A

Binds onto receptors found on renal cells and RBC

Inhibit protein synthesis - Causes cell death

24
Q

E coli 0157 features (5)

A

Low infectious dose
Found in cattle
Person to person or animal contact spread
High risk in extreme ages and immunocomprimised
Produces verotoxin (VTEC) - Same as Shiga-like toxins
Incubation of 1-14 days

25
Q

What disease does E Coli 0157 cause

A

Haemolytic Ureamic Syndrome (HUS)

26
Q

HUS presentation (6)

A
Abdominal pain
Fever
Pallor
Bloody diarrhoea
Petechiae - Tiny purple, red, brown spots
Oliguria - Less urine output
27
Q

Capylobacter features (5)

A

Most common cause of gastroenteritis
Self limiting but can be invasive (bacteraemia) in inmmunocomprimised
16-48 hours incubation
Associated with food hygiene - Raw poultry
Less likely to spread person to person

28
Q

Salmonella features (5)

A

12-48 hours incubation
Found in poultry, meat,raw eggs and reptiles
Outbreaks can cause bacteraemia
They are serogrouped according to different antigens on the body
Causes D and V, fever and blood

29
Q

Listeria monocytogenes (fridge organism) in gastroenteritis (5)

A

Gram positive rod
Incubates in 9-48 hours
Presents with fever, muscle aches, diarrhoea
Pregnant women may have mild symptoms
Found in unpasteurized milk products, deli counter (cold counter)

30
Q

Causes of viral gastroenteritis (2)

A

Norovirus

Rotavirus