Ruminants Contribute Fecal Contamination to the Urban Household Environment in Dhaka, Bangladesh

Environ Sci Technol. 2016 May 3;50(9):4642-9. doi: 10.1021/acs.est.5b06282. Epub 2016 Apr 19.

Abstract

In Dhaka, Bangladesh, the sensitivity and specificity of three human, three ruminant, and one avian source-associated QPCR microbial source tracking assays were evaluated using fecal samples collected on site. Ruminant-associated assays performed well, whereas the avian and human assays exhibited unacceptable cross-reactions with feces from other hosts. Subsequently, child hand rinses (n = 44) and floor sponge samples (n = 44) from low-income-households in Dhaka were assayed for fecal indicator bacteria (enterococci, Bacteroidales, and Escherichia coli) and a ruminant-associated bacterial target (BacR). Mean enterococci concentrations were of 100 most probable number (MPN)/2 hands and 1000 MPN/225 cm(2) floor. Mean concentrations of Bacteroidales were 10(6) copies/2 hands and 10(5) copies/225 cm(2) floor. E. coli were detected in a quarter of hand rinse and floor samples. BacR was detected in 18% of hand rinse and 27% of floor samples. Results suggest that effective household fecal management should account not only for human sources of contamination but also for animal sources. The poor performance of the human-associated assays in the study area calls into the question the feasibility of developing a human-associated marker in urban slum environments, where domestic animals are exposed to human feces that have been disposed in pits and open drains.

MeSH terms

  • Animals
  • Bacteroidetes
  • Bangladesh
  • Environmental Monitoring*
  • Escherichia coli*
  • Feces / microbiology
  • Humans
  • Ruminants / microbiology
  • Water Microbiology