Dirt Floors and Domestic Animals Are Associated with Soilborne Exposure to Antimicrobial-Resistant E. coli in Rural Bangladeshi Households.

Soil can harbor enteropathogens and antimicrobial-resistant organisms from domestic animals. We enrolled 49 households with young children (28 soil floors and 21 concrete floors) in Bangladesh and recorded animal ownership/management. Staff swabbed the floor of children's sleeping area and collected floor dust and child hand rinses. We used IDEXX QuantiTray/2000 with and without cefotaxime supplementation to enumerate cefotaxime-resistant and generic E. coli. Soil floors had 40 times more dust than concrete (8.0 vs 0.2 g/m2, p-value = 0.005). We detected E. coli on 100% of soil vs 86% of concrete floors and cefotaxime-resistant E. coli on 89% of soil vs 43% of concrete floors (p-values <0.05). Cefotaxime-resistant E. coli prevalence on floors increased with animal cohabitation: 36% in compounds without animals, 79% in compounds with animals, and 100% if animals stayed indoors overnight or if floors had animal feces; associations were strongest for chickens. Compounds with soil floors and animals had the highest contamination; those with concrete floors and no animals had the lowest. In multivariable models, generic and cefotaxime-resistant E. coli counts were 1.5-2 log higher on soil floors; counts on floors and child hands were 0.17-0.24 log higher for every 10 chickens owned (p-values <0.05). Efforts to mitigate infections and antimicrobial resistance in low-income countries should test flooring improvements and hygienic animal management.