Drug-Resistant Shigella Surges Among Gay and Bisexual Men

Dr Sheena Meredith

January 27, 2022

A significant rise in infections with an "extremely antibiotic-resistantShigella sonnei strain has been detected as a result of ongoing surveillance by the UK Health Security Agency (UKHSA).

The Agency said that between September 1 last year and January 10, 2022 - 4.5 months - a total of 47 cases were found (more than 10 per month), compared with just 16 cases in 17 months between April 1, 2020 and August 31, 2021 (roughly one per month).

A separate bulletin issued by the Agency in December said that the recent cases were identified by whole genome sequencing, and those affected included 25 men and 2 women, with most cases among gay, bisexual, and other men who have sex with men (MSM).

The vast majority of cases were found in London (n=16), with others in the East of England (n=1), Yorkshire & Humber (n=1), North West (n=2), North East (n=1), East Midlands (n=1), South West (n=1), and South East (n=2). Before the onset of the illness, two cases had travelled to Spain, one to Turkey, and one to an unspecified location.

The UKHSA said it has been monitoring this strain since 2018, and that recent cases show that antibiotic resistance is increasing. The strain typically displays genotypic resistance markers against macrolides, fluroquinolones, aminoglycosides, sulphonamide, trimethoprim, and tetracycline. In addition, most strains from recent cases carry blaCTX-M-27, an antimicrobial resistance gene associated with extended spectrum β-lactamase production.

Limited Treatment Options

Antibiotic treatment is recommended for severe shigellosis symptoms (fever, bloody diarrhoea, and/or sepsis), as well as for those requiring hospital admission, those with prolonged diarrhoea, or people who have underlying immunodeficiency. However due to the problem of increasing resistance, effective antibiotic treatments are limited, and first-line agents such as quinolones, azithromycin and ceftriaxone will not be effective to treat severe cases, the Agency warned.

Oral treatment options for S sonnei are limited to antibiotics such aschloramphenicol, mecillinam, and fosfomycin. Use of either of the latter two would be off-label or unlicensed, and they should only be considered for treating uncomplicated cases such as prolonged diarrhoea. As there is a lack of evidence of efficacy in severe infections, they should not be used in immunocompromised patients or cases with sepsis or severe colitis.

In severe cases consideration should be given to intravenous agents, such as ertapenem or meropenem, and patients may need hospitalisation.

Public Heath Threat

The Agency also warned that Shigella is very infectious and specified the primary public health risks as:

  • Rapid spread of this strain among MSM high-risk sexual networks

  • Spill over into the community, with cases among food handlers or carers (as has been seen in previous international outbreaks)

  • Treatment failure in severe cases of shigellosis

  • Potential spread of resistance determinants to other gastrointestinal bacteria

Gay, bisexual, and other MSM have been urged to take any symptoms seriously and to seek medical advice from their GP or sexual health clinic, mentioning Shigella, if they are unwell. Symptoms of infection are typically seen between 1 and 4 days after exposure and include fever, intestinal cramps and diarrhoea, sometimes bloody. It spreads through the faecal-oral route is often mistaken for food poisoning.

Dr Gauri Godbole, consultant medical microbiologist at UKHSA, issued advice on good hygiene after sex to men potentially at risk: "Avoid oral sex immediately after anal sex, and change condoms between anal or oral sex and wash your hands with soap after sexual contact.

"Men with Shigella may have been exposed to other STIs, including HIV, so a sexual health screen at a clinic or ordering tests online is recommended.

"If you have been diagnosed with Shigella, give yourself time to recover. Keep hydrated and get lots of rest.

"Don’t have sex until 7 days after your last symptom and avoid spas, swimming, jacuzzis, hot tubs, and sharing towels, as well as preparing food for other people until a week after symptoms stop."

Takudzwa Mukiwa, head of social marketing programmes at the Terrence Higgins Trust echoed this advice and commented: "We’ve been working closely with the UKHSA to get the message out about Shigella to men who have sex with men – about the risk of infection, how to prevent it, and how to treat it. It’s vital for people to be aware of Shigella and not dismiss these symptoms."


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