Community human-to-human transmission of multidrug-resistant Enterobacterales in high-income countries: A systematic review

Abstract Background Human-to-human transmission of multidrug-resistant Enterobacterales (MDRE) incommunity settings in high-income countries (HICs) remains poorly characterized. Objectives To assess: (i) human reservoirs of MDRE in community settings of HICs; (ii) the dynamics of human-to-human MDRE transmission; and (iii) opportunities for intervention. MethodsData sources We systematically searched PubMed, Cochrane Library, EMBASE, Scopus, and Web of Science through December 2024. Study eligibility criteria We included studies reporting community-acquired MDRE, human-to-human transmission, or fecal carriage in HICs. Studies conducted in low- and middle-income countries, nursing homes, or hospital settings were excluded. Participants Community-dwelling individuals of any age residing in HICs. Interventions Any intervention addressing MDRE transmission or antimicrobial resistance, including infection prevention or antimicrobial stewardship. Assessment of risk of bias Risk of bias was evaluated using the Joanna Briggs Institute critical appraisal tools appropriate to each study design. Methods of data synthesis Data were synthesized narratively, with prevalence estimates summarized descriptively across time periods and world regions. Results A total of 105 articles were included. Prevalence estimates of extended-spectrum β-lactamases-Enterobacteriaceae carriage in the community increased over time (from 3.2% [IQR, 2.1–4.6] (median [interquartile range]) in 2002–2009, to 19.3% [IQR, 12.5–25.7] in 2018–2021), and the highest prevalence were reported in Eastern Mediterranean countries (13.5% [IQR, 12.9–14.1]), followed by Western Pacific Regions (12.5% [IQR, 5.1–20.3]). Prevalence of carriage among household members of an index carrier ranged from 8–37%. Few data were reported on infection control interventions to prevent community MDRE transmission. The impact of antimicrobial stewardship programs on antimicrobial resistance is unknown. Conclusions Evidence on MDRE transmission dynamics in community settings of HICs is limited. Well designed studies and evaluations of community-based interventions are urgently needed.