A description of the inter-patient antimicrobial resistance transmission within a tertiary hospital setting and investigating the relationship with physical separation on the ward.
The extent of antimicrobial resistance(AMR) dispersal and contribution to patterns of patient AMR carriage is little understood, particularly in resource-limited settings. We performed metagenomic resistome characterisation on rectal swabs collected from adult male inpatients in a “Nightingale” model general medicine ward in the Insein Hospital, Myanmar. Resistome characteristics were validated by targeted quantitative PCR and related to patient spatial distribution through DSTLM analysis. Univariate and multivariate regression analysis was used to identify clinical and treatment variables that predicted AMR gene dispersion patterns.A total of 453 de novo assembled resistance genes were identified within the rectal sample metagenomes. A weak but statistically significant positive correlation was identified between resistome similarity scores and spatial distance scores, a (r=0.12, p=0.04). DSTLM analysis identified 19 individual AMR determinants whose carriage showed contributed significantly to resistome-location relationships. These genes included those encoding clinically important resistance phenotypes, such as ß-lactamase activity (OXA-1, NDM-7; (p <0.003), trimethoprim resistance (dfrA14, p=0.0495), and chloramphenicol resistance (catB3, p =0.002). However, the practice of grouping patients within the ward according to their condition (e.g. clustering TB patients) significantly predicted carriage of AMR determinants that contributed to distance-resistome relationships, suggesting dispersal patterns primarily reflected approaches to patient management, rather than patient-to-patient transmission. While patient-patient almost certainly occurs, patient grouping practices appear to be the most substantial contributor to AMR clusters, consistent with common antibiotic exposures. Overall, the number of genes showing significant spatial distribution was small relative to the total identified, suggesting that transmission beyond the hospital environment is the principal driver of intestinal AMR carriage in this population.