GPs in Victoria are being asked to hold off prescribing antibiotics for shigellosis, except in priority cases such as health workers, to combat increasing drug resistance to the bacteria.

Victorian health officials have released advice for doctors requesting they ask for stool tests and antibiotic sensitivities when testing for shigellosis.

Antibiotic treatment should be reserved for food workers, healthcare professionals, child-care workers, children under six, people working or living in aged care homes, and the immunocompromised, they say.

The advice is a change from the previous recommendation, which was to treat all patients with antibiotics.