What is the issue?
The department has observed an increase in the number of shigellosis cases resistant to multiple antibiotics. It is important to ensure all suspected cases of shigellosis have stool samples sent for CULTURE and ANTIMICROBIAL SENSITIVITY testing.
Who is at risk?
High risk populations include men who have sex with men and all travellers from overseas.
Symptoms and transmission
Transmission of Shigella is by the faecal-oral route, and the incubation period is usually one to three days.
Shigellosis is characterised by an acute onset of diarrhoea, fever, nausea, vomiting and abdominal cramps. Typically, stools contain blood, mucus and pus, although some people will present with watery diarrhoea without these features.
Cases remain infectious while bacteria are continuing to be shed in the faeces, which can last for up to four weeks after symptoms resolve. Rarely, the carrier state may persist for months or longer. Appropriate antibiotic treatment usually reduces the duration of carriage to a few days and is recommended for public health reasons as ingestion of a very low number of bacteria can cause infection.
Prevention / treatment
Stool culture is the preferred diagnostic test for shigellosis accompanied by antibiotic sensitivity testing to ensure that doctors prescribe appropriate antibiotics for their patients.
Because of the small infectious dose, food handlers, child care workers and health care workers should be excluded from work until two faecal specimens (collected 24 hours apart but not sooner than 48 hours following the discontinuance of antibiotics) are found to be free of Shigella. The Department will arrange follow-up screening of cases.
To help prevent the spread of Shigella patients should:
- thoroughly wash hands after going to the toilet and before eating or preparing food;
- not prepare food for others until 48 hours after symptoms completely resolve; and
- avoid having sex for seven days after symptoms completely resolve.
Antimicrobial resistance is increasing against some antibiotics recommended in the Therapeutic Guidelines for treatment of shigellosis. Susceptibility testing of shigella isolates in 2016 in Victoria found 64 per cent resistant to ampicillin, 87 per cent resistant to trimethoprim and 49 per cent resistant to azithromycin. The majority (80 per cent) of 2016 isolates are sensitive to ciprofloxacin. The department recommends that clinicians seek advice from their diagnostic laboratory on the results of antibiotic susceptibility testing in each instance for their patient.
Under the Public Health and Wellbeing Regulations (2009), shigellosis is required to be notified to the Department of Health & Human Services by medical practitioners within five days of initial diagnosis. Notifications can be made online at http://ideas.health.vic.gov.au via telephone on 1300 651 160 or faxed on 1300 651 170.
Better Health Channel fact sheet: Gastroenteritis - shigella
Communicable Disease Prevention and Control Section - phone 1300 651 160 or email firstname.lastname@example.org.