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

<h2>Abstract</h2><h3>Background</h3> Human-to-human transmission of multidrug-resistant Enterobacterales (MDRE) incommunity settings in high-income countries (HICs) remains poorly characterized. <h3>Objectives</h3> 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. <h3>MethodsData sources</h3> We systematically searched PubMed, Cochrane Library, EMBASE, Scopus, and Web of Science through December 2024. <h3>Study eligibility criteria</h3> 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. <h3>Participants</h3> Community-dwelling individuals of any age residing in HICs. <h3>Interventions</h3> Any intervention addressing MDRE transmission or antimicrobial resistance, including infection prevention or antimicrobial stewardship. <h3>Assessment of risk of bias</h3> Risk of bias was evaluated using the Joanna Briggs Institute critical appraisal tools appropriate to each study design. <h3>Methods of data synthesis</h3> Data were synthesized narratively, with prevalence estimates summarized descriptively across time periods and world regions. <h3>Results</h3> 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. <h3>Conclusions</h3> Evidence on MDRE transmission dynamics in community settings of HICs is limited. Well designed studies and evaluations of community-based interventions are urgently needed.