Bacterial Gastroenteritis

Question 1

Campylobacter jejuni

Answer 1

Most common cause of acute infective diarrhoea
Spiral, gram negative rods
Usually infects caecum and terminal ileum. Local lymphadenopathy is common
May mimic appendicitis as it has marked right iliac fossa pain
Reactive arthritis is seen in 1-2% of cases

Question 2

Shigella spp.

Answer 2

Members of the enterobacteriaceae
Gram negative bacilli
Clinically causes dysentery
Shigella soneii is the commonest infective organism (mild illness)
Usually self limiting, ciprofloxacin may be required if individual is in a high risk group

Question 3

Salmonella spp

Answer 3

Facultatively anaerobic, gram negative, enterobacteriaceae
Infective dose varies according to subtype
Salmonellosis: usually transmitted by infected meat (especially poultry) and eggs

Question 4

E. coli

Answer 4

Enteropathogenic
Enteroinvasive: dysentery, large bowel necrosis/ulcers
Enterotoxigenic: small intestine, travelers diarrhoea
Enterohaemorrhagic: 0157, cause a haemorrhagic colitis, haemolytic uraemic syndrome and thrombotic thrombocytopaenic purpura

Question 5

Yersinia enterocolitica

Answer 5

Gram negative, coccobacilli
Typically produces a protracted terminal ileitis that may mimic Crohns disease
Differential diagnosis acute appendicitis
May progress to septicaemia in susceptible individuals
Usually sensitive to quinolone or tetracyclines

Question 6

Vibrio cholera

Answer 6

Short, gram negative rods
Transmitted by contaminated water, seafood
Symptoms include sudden onset of effortless vomiting and profuse watery diarrhoea
Correction of fluid and electrolyte losses are the mainstay of treatment
Most cases will resolve, antibiotics are not generally indicated