What is the issue?
A rise in the number of shigellosis cases who are found to be resistant to multiple antibiotics has prompted the department to modify its treatment recommendations to minimise the use of antibiotics, in line with published therapeutic guidelines. Previously, the department recommended antibiotic treatment for all confirmed cases of shigellosis.
All suspected cases of shigellosis should have stool samples sent for culture and antibiotic sensitivity testing so that treatment can be better targeted to the patient’s specific infection.
Who is at risk?
The highest risk populations for contracting shigellosis are men who have sex with men (MSM) and travellers to countries with high rates of endemic disease.
Symptoms and transmission
Shigella is transmitted by the faecal-oral route and requires only a small infectious dose. The time to symptoms is usually one to three days but can be from 12 hours to one week in some cases.
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. Shigellosis is usually a self-limiting infection, although in vulnerable individuals, such as the immunocompromised, it can be a potentially serious infection.
Cases remain infectious while bacteria continue to be shed in the faeces, so people can be infectious for up to four weeks after symptoms resolve. Although appropriate antibiotic treatment usually reduces the period of carriage to a few days, high rates of antibiotic resistance have prompted the department to recommend limiting the use of antibiotics to priority cases only, where there is the greatest risk of onward transmission.
Supportive treatment, including plenty of fluids, is all that is required for most people. Anti-motility drugs are contraindicated as they may prolong diarrhoea, fever and bacterial shedding.
Who should receive antibiotics?
Antibiotics reduce the period a person can transmit Shigella, however antibiotic use should be restricted to priority groups where possible and the choice of antibiotic informed by antibiotic sensitivities and the likely source of the infection. To reduce transmission amongst vulnerable people, antibiotic therapy for shigellosis should be limited to the following priority groups:
- Food handlers.
- Health care workers.
- Childcare workers.
- People living or working in aged care facilities, prisons, disability group homes and other residential facilities.
- Children younger than six years.
Due to an increased risk of complications and poorer outcomes, patients with severe disease or those who are immunocompromised should also receive antibiotics. People living with HIV who develop shigellosis only require antibiotics if their CD4 count is <200 cells/mm3 – seek the advice of an infectious disease physician. Further information is provided below on treatment of shigellosis acquired through MSM contact.
If indicated, what antibiotics should be used?
Empirical antibiotic treatment is recommended in these priority groups, informed by the likely source of the infection until antibiotic susceptibilities are known. If diagnosis was by PCR alone, empirical treatment should be completed. Note that antimicrobial resistance is increasing in Victoria against some antibiotics recommended in the Therapeutic Guidelines and recent Victorian antimicrobial sensitivity data to assist with the choice of empirical therapy are available. The department recommends that clinicians seek advice from an infectious diseases physician, where appropriate, as well as their diagnostic laboratory on the results of antibiotic susceptibility testing in each instance for their patient.
Overseas acquired shigellosis
High levels of antimicrobial resistance in Shigella species are currently being reported by many overseas countries. Priority cases whose disease was not acquired in Australia should be treated empirically with azithromycin until sensitivities are known.
MSM acquired shigellosis
Currently very high levels of antimicrobial resistance amongst Shigella species are circulating in the MSM community. There is therefore no suitable empirical oral antibiotic of choice for those who have acquired their infection through MSM contact. Hygiene and safe sex messages should be emphasised as a matter of urgency and rimming should be avoided until at least three weeks after symptoms resolve. Antibiotics should be considered only after sensitivities are known, or on the direction of the department as part of a response to a point source outbreak. The exceptions are MSM cases with severe shigellosis or who are immunocompromised, for whom parenteral ceftriaxone or similar third generation cephalosporins are among the limited empirical options. It is particularly important that priority groups who have acquired shigellosis through MSM contact are excluded from work or isolated if living in a residential facility until advised otherwise by the department.
Prevention of onward transmission
Reinforce good hygiene practices, especially handwashing after using the toilet and before eating or preparing food. Cases should not prepare food for others until 48 hours after symptoms resolve. Kitchen and bathroom surfaces should be regularly cleaned.
Safe sex messages should be given to both men and women diagnosed with Shigella infection, including:
- Avoid faecal-oral exposure during sex, especially rimming which may significantly increase transmission
- Abstain from sex while symptomatic and for seven days after symptoms completely resolve
- Use barrier protection (condoms, dental dams) for vaginal, anal, oral-anal and oral sex for a further two weeks
- Wash body and hands before and after sex (e.g. showering), especially after removing condoms
Advise cases who are food handlers, health care workers, childcare workers and staff of residential facilities not to return to work until advice from the department is obtained. Those living in residential facilities should be isolated (including cohorting with other ill residents if necessary) to reduce onward transmission. Others with shigellosis should be advised against visiting residential facilities and vulnerable people. Children must be excluded from childcare and primary school until 24 hours after symptoms resolve.
Under the Public Health and Wellbeing Regulations (2009), shigellosis is required to be notified to the Department of Health and Human Services by medical practitioners within five days of initial diagnosis. Notifications can be made online or faxed on 1300 651 170. More information regarding the public health management of cases such as workplace exclusion and isolation in residential facilities of cases may be obtained from the department via telephone on 1300 651 160.
Better Health Channel – Gastroenteritis –
For more information please contact the Communicable Disease Prevention and Control section at the Department of Health and Human Services on 1300 651 160 (24 hours).