GI Microbiology - GI system

GI Microbiology

Salmonella:

 Gram negative rod
 1-7 day incubation
 Faecal –oral route
 Bacteria-mediated endocytosis and intestinal epithelial invasion
 Symptoms include: diarrhoea (maybe bloody), fever and cramping
 Complications include: bacteriaemia, metastatic infections e.g.
osteomyelitis
 Disease is usually self-limiting and treated with supportive I.V fluids

Campylobacter:

 Include: C. Jejuni, C. Coli and C. Lari
 Gram-negative spiral rod
 2-5 day incubation
 Invades small/large bowel and causes acute inflammation
 Transmission is usually foodborne
 Diarrhoea (maybe bloody), abrupt onset of abdominal pain
 Complications include: GI haemorrhage, bacteraemia, toxic megacolon,
reactive arthritis,
 Disease is usually self-limiting

Shigella:

 Shigella sonnei
 Gram-negative rod
 1-7 day incubation
 Low infectious dose (very contagious)
 Invasion of colonic mucosal cells leading to inflammatory response
 Shiga toxin produced by S. dysenteriae inhibits protein synthesis leading
to cell death and vascular damage.
 Symptoms: abdominal cramps, mucoid/bloody diarrhoea, fever and
vomiting
 Treatment: fluoroquinolone, amoxicillin

Escherichia coli:

 Commensal to highly pathogenic strains
 Vero cytotoxin producing E. Coli include enterohaemorrhagic E. coli
(EHEC)