Associations between floor material and E. coli contamination in rural Bangladeshi households

Soil floors are common in low-income countries and can harbor contamination from fecal waste. Soil/dust ingestion from floors or indirectly via hands, water and food can contribute to children's ingestion of fecal organisms. We assessed if finished (e.g., concrete) floors are associated with lower E. coli contamination in the domestic environment in rural Bangladesh.

We collected samples from 1864 households over 3.5 years, including stored drinking water, child and caregiver hand rinses, courtyard soil, food, and flies (n = 24,118 samples), and enumerated E. coli using IDEXX Quanti-Tray/2000.

Controlling for socio-demographics, water/sanitation status, and animal ownership, households with finished floors had slightly lower log10-transformed E. coli counts (Δlog10 = -0.10 (-0.20, 0.00)) and prevalence (prevalence ratio [PR] = 0.90 (0.83, 0.98)) on child hands than households with soil floors; floor material was not associated with contamination levels in other sample types. In subgroup analyses, finished floors were associated with lower E. coli on child hands following heavy rainfall (Δlog10 = -0.23 (-0.39, -0.07)), above-median temperature (Δlog10 = -0.18 (-0.30, -0.06)), and in households with more domestic animals (Δlog10 = -0.16 (-0.32, -0.01)). Finished floors were also associated with slightly lower contamination of stored water following heavy rainfall (PR = 0.89 (0.81, 0.99)) and above-median temperature (PR = 0.91 (0.84, 0.98)), and lower contamination of stored food following higher rainfall and temperature but the associations for food were not statistically significant.

Measures to control enteric infections in low-income countries should test flooring improvements to reduce exposure to fecal contamination.