Tuesday 22 December 2015

Public Health England (PHE) have recently identified five cases of Shigella sonnei phage type 6 which show high levels of antimicrobial resistance – typically only seen before in Shigella infections associated with travel and therefore imported. The Shigella sonnei isolated in these cases are clustered by whole genome sequencing suggesting they belong to an outbreak. Four cases are adult men who have sex with men (MSM) from London with sample dates from 21 September to 27 October inclusive. The fifth case, from mid-November, is an adult man from outside London with a likely sexual exposure in London. There is no indication that case characteristics differ significantly from those of previous Shigella outbreaks.¹ National surveillance data suggest that transmission of Shigella sonnei and Shigella flexneri PT2a has intensified in MSM in England over the past three years.²

The isolates from these cases have genes conferring resistance to amoxicillin, ceftriaxone (first line treatment for HIV-positive individuals with invasive shigellosis), trimethoprim, sulphonamides, tetracycline, including the extended-spectrum beta-lactamase (ESBL) resistance gene CTX-M-27 and macrolide resistance genes ermB/mph(A). These resistance genes are plasmid mediated and therefore readily transmissible. The isolates are phenotypically sensitive to quinolones, carbapenems, aminogylcosides and fosfomycin.

Our primary concerns are as follows: a) that this strain might spread rapidly among HIV-positive MSM in high-risk sexual networks, including outside of London b) potential spread of resistance to other Shigella and other organisms c) the possibility of treatment failure for severe shigellosis disease in the immunocompromised.

PHE would therefore recommend that all GUM and HIV clinicians:

• Provide written advice to all MSM attending their services (especially HIV positive patients) on how to prevent infection with Shigella. Materials are available on the PHE website here: https://www.gov.uk/government/publications/shigella-leaflet-and-poster

• Obtain appropriate and timely stool samples for patients presenting with acute diarrhoea, abdominal pain and fever

• Provide advice to patients with Shigella on how to prevent onward transmission

• Discuss the need for antibiotic management of severe disease (fever, bloody diarrhoea or signs of sepsis) with their microbiologist

• Notify cases to their local Health Protection Team

• Record any Shigella diagnosis in England using the appropriate SHHAPT code (SG1, SG2 or SG3) in the patient's medical record, so that it can be reported in GUMCAD. See SHHAPT code look-up here: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/420625/GUMCADv2_SHHAPT_Code_Look-up.pdf

For further information please contact Dr Paul Crook ([email protected]), Dr Nigel Field ([email protected]) and Dr Gauri Godbole ([email protected]).

References
1. Simms I et al. Intensified shigellosis epidemic associated with sexual transmission in men who have sex with men--Shigella flexneri and S. sonnei in England, 2004 to end of February 2015. Euro surveillance. 2015;20(15). Epub 2015/05/09. http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=21097
2. Gilbart VL et al. Sex, drugs and smart phone applications: findings from semistructured interviews with men who have sex with men diagnosed with Shigella flexneri 3a in England and Wales. Sexually transmitted infections. 2015. Epub 2015/04/30. http://sti.bmj.com/content/early/2015/04/28/sextrans-2015-052014.abstract