Shigellosis, a highly infectious disease caused by the bacterium Shigella sonnei, is spreading faster in England through sexual contact than initially thought. A recent genomic epidemiology study has revealed that sexually transmitted cases of the infection are being transmitted more widely and rapidly, posing concerns for public health officials.
The research, led by Julia E Marshall's team and published in The Lancet Infectious Diseases, analysed a large dataset of Shigella sonnei infections across England. Using cutting-edge genomic tools, the researchers were able to trace transmission patterns, confirming previous suspicions that sexually transmitted Shigella spreads more extensively than other forms.
Dr Mathew Beale, Senior Staff Scientist and molecular and computational microbiologist at the Wellcome Sanger Institute, described the study's analysis as 'impressive and comprehensive', praising its ability to formally quantify the spread of sexually transmitted shigellosis. However, Dr Beale also highlighted limitations in the research, including an assumption that men without recent travel history to high-risk areas were predominantly from the gay, bisexual, and other men who have sex with men (GBMSM) community.
According to Dr Beale, the study's use of laboratory location as a proxy for patient geographical location is also problematic. This approach can lead to inaccuracies, especially since individuals involved in GBMSM sexual transmission networks often acquire infections away from their homes and only seek medical attention upon return. The research suggests that sexually transmitted Shigella spreads faster, but Dr Beale noted that it does not conclusively demonstrate a quicker growth in drug resistance.
Despite these limitations, the study's findings are significant, providing new insights into the transmission dynamics of sexually transmitted infections and antimicrobial resistance. The research contributes to our understanding of this growing public health concern, highlighting the need for targeted interventions and surveillance strategies to combat its spread.