Factors influencing antibiotic-resistant bacteria colonization among community and hospitalized individuals in Chennai, India: an Antibiotic Resistance in Communities and Hospitals (ARCH) study

Colonization with antibiotic-resistant bacteria (ARB) increases the risk for antibiotic-resistant infections. Our previous study documented a high level of colonization with ARBs in a suburban area of Chennai, a city in South India. Here, we aimed to identify potential risk factors for colonization with extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) and carbapenem-resistant Enterobacterales (CRE). Adult participants were enrolled in community and hospital surveys from November 2020 through March 2022, and ARB isolation was done from stool specimens. Multivariable logistic regression was used to calculate adjusted odds ratios (aOR) with 95% confidence intervals (CI). In the community, the adjusted odds of ESCrE colonization were lower among those reporting consumption of animal products (1–2 days a week, aOR: 0.51; 95% CI 0.27–0.96; > 2 days a week, aOR: 0.48; 95% CI 0.25–0.94). Among hospitalized patients, the adjusted odds of CRE colonization was higher among those with prior antibiotic use (aOR: 1.50; 95% CI 0.97–2.32) and who underwent invasive procedures (aOR: 1.80; 95% CI 0.95–3.39). No significant associations were identified for other risk factors among community or hospital participants and colonization outcomes. Drivers of ARB colonization may be difficult to ascertain in high-burden settings. However, healthcare-based strategies to reduce ARB transmission should continue to emphasize infection prevention and control as well as antibiotic stewardship. Additional studies are needed to understand community factors contributing to ARB colonization.