Abstract / Summary
Abstract Background Shigella is a genus of Gram-negative bacteria that cause bacillary dysentery, also known as shigellosis. Transmission occurs through the faecal-oral route, and disease burden is concentrated in LMICs due to suboptimal sanitation and lack of clean water. Recent surveillance data from HICs have demonstrated increasing incidence of domestically acquired shigellosis, particularly among men who have sex with men (MSM), many of whom are also people living with HIV (PLWHIV). The overlap of these pathogens is largely assumed to arise from overlap in sexual transmission networks, specifically through practices involving oral-anal contact and condomless sex. However, the exact relationship between HIV status and Shigella has not been well characterised, particularly whether the association exists in LMICs and what role HIV-mediated immunological susceptibility may play. Methods A systematic search of peer-reviewed literature was conducted in PubMed and Embase to identify epidemiological and biological drivers of HIV- Shigella coinfection across both HIC and LMIC settings. Records were imported into Covidence and selected through title/abstract screening followed by full-text assessment by one author according to predefined inclusion and exclusion criteria. Full-text assessment was independently confirmed by a second reader. Using the included studies, citation searching was conducted to identify additional studies not captured by the initial search. All evidence was critically appraised following Critical Appraisal Skills Programme (CASP) or Joanna Briggs Institute (JBI) guidelines by one author and synthesised using a narrative approach informed by study quality and reported statistical measures. Results The systematic review search returned 700 unique records, of which 26 were included. Two additional studies were identified through backward citation searching, resulting in 28 studies included overall. Studies were organised into broad epidemiological or biological themes and country income setting. Epidemiological factors associated with HIV- Shigella coinfection included MSM-associated sexual transmission, specific sexual behaviours facilitating faecal-oral exposure, and sociodemographic characteristics. Limited biological evidence suggested that HIV-related immune activation and alterations in the gut microbiota may increase susceptibility to Shigella infection, although temporality remains undefined. Conclusion HIV- Shigella coinfection results from a complex interplay of both population epidemiology and possible biological susceptibility rather than a single mechanism. Current evidence supports the further exploration of links between HIV and Shigella , with implications for both sexual transmission in HICs and endemic transmission in LMIC settings.