Infection with extensively drug-resistant Shigella sonnei harbouring blaCTX-M-27 in a gay man in Italy

Abstract

Outbreaks of Shigella sonnei and Shigella flexneri have been reported recently among gay, bisexual and other men who have sex with men (GBMSM), with transmission linked to sexual contact, particularly practices that involve oral-anal contact or faecal-oral exposure.1–8 The emergence of extensively drug-resistant (XDR) S. sonnei harbouring plasmid-encoded blaCTX-M-27 has raised concerns about the potential spread of this extended-spectrum beta-lactamase (ESBL)-producing gene.4–7 Two ESBL+ Shigella strains have been reported in Italy, one in a 10-year-old girl returning from Albania (2018) and one in a hospitalised patient (2021, no epidemiological or clinical data available).9 10 We present the case of a 35-year-old gay man diagnosed with XDR S. sonnei at our centre in Milan in February 2024. The individual was receiving HIV pre-exposure prophylaxis (PrEP) and doxycycline post-exposure prophylaxis (DoxyPEP). Past medical history included three episodes of gonorrhoeal proctitis, one chlamydial proctitis, a syphilis diagnosis and the detection of rectal HPV DNA. He travelled frequently within and outside of Italy. He presented following the acute onset of afebrile profuse mucous and fatty diarrhoea with tenesmus. He described condomless anal-receptive and oral-anal sexual intercourse with >50 partners in the previous month, including 20 days prior to the onset of symptoms with a man visiting Milan from the UK. The man later disclosed an untreated Shigella infection. On the initial presentation, he was treated empirically with a single dose of tinidazole 2 …