Health officials from Europe and the United Kingdom are sounding the alarm about a multi-country outbreak of extensively drug-resistant (XDR) Shigella infections.
In the United Kingdom, XDR Shigella cases have risen by 53% in 2023, driven primarily by a cluster of 97 cases of an XDR strain of Shigella sonnei with non-susceptibility to penicillins, third-generation cephalosporins, aminoglycosides, tetracycline, sulphonamides, quinolones, and azithromycin (4 additional infections with the same strain were reported in late 2022). The cases have been reported across England, mainly in men who have sex with men (MSM), according to the UK Health Security Agency (UKHSA).
Shigellosis is a highly infectious gastrointestinal condition caused by one of the four species of Shigella bacteria: S sonnei, S flexneri, S boydii, or S dysenteriae. Symptoms range from mild diarrhea to severe dysentery, with more severe cases requiring antibiotics. Although shigellosis is commonly associated with exposure to food or water that has been contaminated by human feces and is commonly mistaken for food poisoning, oral and anal sex has become a common mode of transmission, particularly among MSM.
UKHSA officials say Shigella infections have been climbing since the end of COVID-19 pandemic restrictions in July 2021, and are now higher than they were pre-pandemic. While not all cases are antibiotic-resistant, the current XDR strain is one of two resistant strains that have been circulating in the United Kingdom since 2022.
"This is a concerning rise in cases of this antibiotic resistant strain, meaning treatment can be very difficult," UKHSA consultant medical microbiologist Gauri Godbole, MD, said in an agency news release last week. "One of the best ways to protect yourself and your partners is to practice good hygiene after sex."
Cluster of cases in Europe
In a communicable diseases threat report published last week, officials from the European Centre for Disease Prevention and Control (ECDC) said the cases reported in the UK belong to a cluster of XDR S sonnei infections that have sickened MSM in the Netherlands (145 cases), Norway (2 cases), and Portugal (1 case). They warned that the strain will likely spread to other countries.
"Further cases are very likely to occur, particularly among MSM, not only in the affected countries but also in other Member States, given the interconnected nature of MSM sexual networks in Europe," the ECDC said. "It is also likely that cases may already be present in other Member States but have not yet been detected."
The ECDC is encouraging Member states to increase awareness of the XDR Shigella strain among clinicians and microbiology laboratories and to ensure that antimicrobial susceptibility testing of Shigella is conducted for gastroenteritis cases in MSM to guide appropriate antibiotic treatment.
ECDC officials also recommend that public health authorities work with civil society organizations to raise awareness among MSM about how they can protect themselves, and when they should seek treatment.
Further cases are very likely to occur, particularly among MSM, not only in the affected countries but also in other Member States, given the interconnected nature of MSM sexual networks in Europe.
