9. Enteric fever Flashcards Preview

ESA 2 - Infection > 9. Enteric fever > Flashcards

Flashcards in 9. Enteric fever Deck (14)
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1
Q

What is an alternative name for enteric fever?

A

Typhoid and paratyphoid (generally milder)

2
Q

Where is enteric fever endemic?

A

Mainly Asia

also Africa and S America

3
Q

What is the causative agent of enteric fever?

A

Salmonella enterica serovar Typhi / Parathyphi A B or C

4
Q

What type of bacteria is S. enterica? What is its gram stain appearance?

A

Enterobacteriaceae

Aerobic gram-negatie rod

5
Q

Name 3 S. enterica virulence factors.

A
  1. gram-negative endotoxin, VI antigen
  2. invasin - allows intracellular growth
  3. fimbriae - adhere to epithelium over ileal lymphoid tissue (Peyer’s patches), allowing entry into blood and lymph
6
Q

How is S. enterica transmitted?

A

faecal-oral route from contaminated food/water (human pathogen only)

7
Q

What is the incubation period of S. enterica?

A

7-14 days

8
Q

What are the signs and symptoms of enteric fever?

A

Symptoms:

  1. headache
  2. abdominal discomfort, constipation or diarrhoea
  3. dry cough

Signs:

  1. fever
  2. relative bradychardia
9
Q

What type of disease is enteric fever?

A

systemic (bacteraemia)

10
Q

What are the possible complications of enteric fever? What is the mortality rate if untreated?

A
  • intestinal haemorrhage and perforation

- 10% mortality

11
Q

What investigations are indicative of enteric fever?

A
  1. FBC: moderate anaemia, relative lymphopenia
  2. LFTs: raised transaminase and bilirubin
  3. Blood (and faeces) culture

(serology not reliable)

12
Q

What is the treatment strategy for enteric fever?

A

CEFTRIAXONE or AZITHROMYCIN (7-14 days)

13
Q

Why is treatment of S. enterica difficult?

A

rapidly develops resistance (e.g. to chloramphenicol, ampicillin, ciprofloxacin…)

14
Q

How can enteric fever be prevented?

A
  1. food and water hygiene precautions
  2. typhoid vaccine (modest protective effect 50-75%)
    • Vi capsular polysaccharide antigen
    • live attenuated vaccine