Quantifying household-level sharing of antimicrobial-resistant pathogens between pets and their owners: a systematic...

Companion animals are increasingly recognized as potential reservoirs of antimicrobial-resistant (AMR) bacteria, yet the frequency of sharing between pets and their owners remains unclear. We conducted a systematic review and meta-analysis to estimate household-level co-occurrence ('sharing') of AMR pathogens. We searched PubMed, Embase, and Web of Science for studies sampling pets and owners from the same household and assessing genetic or phenotypic relatedness of AMR bacteria. Random-effects generalized linear mixed models were used to estimate pooled prevalences, with subgroup and sensitivity analyses by host health status, pathogen group, typing method, and study design. Across 152 studies, the pooled prevalence of household-level sharing was 3.8% (95% CI: 2.7%-5.1%). Sharing was similarly low among households when pets and owners were healthy or when the pet or owner had an illness unrelated to the pathogen (3.0% in both cases), but higher when a pet or owner had a confirmed infection (9.0%, 95% CI: 5.0%-16.0%). Estimates were comparable for Staphylococci and Enterobacterales. Studies using phenotypic methods alone reported higher prevalences than those using molecular typing, consistent with lower discriminatory resolution. Substantial heterogeneity was observed, but findings were robust across study design, geography, and quality. Household sharing of AMR bacteria between pets and owners appears relatively uncommon under typical conditions and is more strongly associated with infection or active shedding than routine cohabitation.