Outbreak of sexually transmitted, extensively drug-resistant Shigella sonnei in the UK, 2021-22: a descriptive epidemiological study.

BACKGROUND: Shigellosis, traditionally a foodborne and waterborne infection, causes substantial morbidity globally. It is now a leading cause of sexually transmitted gastroenteritis among gay, bisexual, and other men who have sex with men (MSM). We describe an ongoing outbreak of extensively drug-resistant (XDR) Shigella sonnei in the UK. METHODS: Routine laboratory surveillance (Second Generation Surveillance System, Gastrointestinal Data Warehouse) identified an exceedance of S sonnei clade 5 in England, first detected in September, 2021. Cases within this clade were subsequently reported from Scotland, Wales, and Northern Ireland. Confirmed cases in this outbreak were defined as individuals diagnosed with S sonnei clade 5 in the UK, with a specimen date between Sept 1, 2021, and Feb 9, 2022, who were genomically confirmed as part of a ten-single nucleotide polymorphism (SNP) linkage cluster. We used whole-genome sequencing with SNP typing to identify genomic clusters and antimicrobial-resistance determinants, analysing cases across the UK. We collected demographic, epidemiological, and clinical data from people infected with S sonnei clade 5 in England using questionnaires (standard and bespoke outbreak questionnaires). We used descriptive summary statistics to characterise cases. FINDINGS: 72 cases (70 [97%] male, median age 34 years [IQR 27-39]) belonging to the ten-SNP single linkage cluster of S sonnei clade 5 were identified between Sept 4, 2021, and Feb 9, 2022. Isolates were predominantly XDR, with 66 (92%) of 72 harbouring bla_CTX-M-27, a plasmid-mediated gene for production of extended-spectrum ß-lactamases (ESBLs). Of 33 cases with clinical data, 19 (58%) received antibiotics and eight (24%) were hospitalised. 21 (78%) of 27 cases with completed bespoke outbreak questionnaires were HIV-negative MSM taking HIV pre-exposure prophylaxis (PrEP) who reported sexual contacts in the UK and Europe within the incubation period. INTERPRETATION: We highlight the rapid dissemination of XDR ESBL-producing S sonnei in sexual networks of MSM. We recommend strengthening shigella testing where clinically indicated, antimicrobial-resistance surveillance, and integrated health promotion messaging among all MSM, including PrEP users, to reduce the burden of shigellosis. FUNDING: National Institute for Health Research Health Protection Research Unit in Gastrointestinal Infections at the University of Liverpool in partnership with the UK Health Security Agency.

A Significant Decrease in the Incidence of Shigellosis in Israel during COVID-19 Pandemic.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes COVID-19 and is mostly person-to-person transmitted through respiratory droplets. The implications of the strategies implemented to prevent COVID-19 transmission on other infectious diseases are unclear. We aimed to appraise trends in the incidence of salmonellosis, shigellosis and campylobacteriosis in Israel during COVID-19 pandemic. Positive stool samples for Salmonella, Shigella and Campylobacter are reported on a monthly basis to the Israel Center for Disease Control from sentinel laboratories, within the framework of a surveillance network of bacterial culture-proven enteric diseases. Age-adjusted incidence rates per 100,000 of shigellosis, salmonellosis and campylobacteriosis were calculated. Mean rates before and after the local onset of COVID-19 pandemic in Israel were compared and Relative Risk Reduction (RRR) was calculated. Joinpoint was used to evaluate secular trends. The mean age-adjusted incidence rate of shigellosis in March-July 2020 was lower than the rate observed in March-July 2018-2019 (RRR = 86.6%), but also decreased for salmonellosis (RRR = 33.0%) and campylobacteriosis (RRR = 30.0%). Using Joinpoint we have shown that the decrease observed for shigellosis was significantly sharper (Annual Percent Change (APC) = -77.7) between February 2020 and May 2020 than for salmonellosis (APC = -14.0) between July 2019 and April 2020 and for campylobacteriosis (APC = -1.1) between January 2018 and July 2020. The preventive measures applied to reduce transmission of COVID-19, including social distancing and hand washing, were ecologically associated with a decreased risk of bacterial enteric diseases in Israel. The association was strongest for shigellosis, a disease that is mostly person-to-person transmitted, as compared to salmonellosis and campylobacteriosis which are mostly foodborne transmitted.