Diarrhoea – Infection Associated

See investigation and treatment guidelines for Acute Diarrhoea in Hospital HealthPathways.

Common: Campylobacter jejuni, Salmonella species (non Typhi), Aeromonas species, Shigella species, and norovirus. C. difficile is particularly common in the elderly (see Diarrhoea – Clostridioides difficile).
Other: Yersinia enterocolitica, Vibrio parahaemolyticus, Plesiomonas shigelloides, enterohaemorrhagic E. coli (0157:H7), amoebic dysentery

Most do not require antimicrobial therapy.
If elderly, immunocompromised, very severe illness, or bacteraemia, treat as below.
If enterohaemorrhagic E. coli (0157:H7) infection (bloody stool and little or no fever) or haemolytic uraemic syndrome suspected, avoid antimicrobials and give supportive therapy.
If pregnant, consult with Infectious Diseases/Clinical Microbiology.

Not recommended unless patient is immunocompromised or has severe symptoms.
Recent travel (e.g. to South-east Asia) may increase likelihood of ciprofloxacin resistance (consider an alternative agent e.g. azithromycin).

If able to take oral therapy

ciprofloxacin

PO 500 mg twice a day for 5 days

If unable to take oral therapy

ceftriaxone

IV 2 g every 24 hours then ciprofloxacin PO as above (5-day total course duration)

Severe penicillin allergy and unable to take oral therapy

ciprofloxacin

IV 400 mg every twelve hours then PO 500 mg twice a day (5-day total course)

Most patients do not require antimicrobial therapy.
Antimicrobial therapy may be considered if illness is severe, or the patient is elderly or immunocompromised.

azithromycin

500 mg once a day for 3 days

Consult Infectious Diseases/Clinical Microbiology.
Only treat if patient is severely ill, septicaemic or immunocompromised.
There is increasing Salmonella species resistance to both of the following antimicrobials, particularly if acquired overseas:

trimethoprim+sulfamethoxazole

(co-trimoxazole)

PO 160 mg/800 mg twice a day for 5 days