Analysis of pit latrine microbiota reveals depth-related variation in composition, and key parameters and taxa associated with latrine fill-up rate

Umer Zeeshan Ijaz, Ozan Gundogdu, Ciara Keating, Miriam van Eekert, Walter Gibson, Julian Parkhill, Faraji Abilahi, Benard Liseki, Viet-Anh Nguyen, Steven Sudgen, Christopher Quince, Jeroen H. J. Ensink, Belen Torondel, Alan W. Walker

Research output: Contribution to journalArticlepeer-review

Abstract

Pit latrines are used by billions of people globally, often in developing countries where they provide a low-tech and low-cost sanitation method. However, health and social problems can arise from a lack of emptying or maintenance of these facilities. A better understanding of the biological and environmental parameters within pit latrines could inform attempts to enhance material decomposition rates, and therefore slow fill-up rate. In this study, we have performed a spatial analysis of 35 Tanzanian pit latrines to identify bacteria and environmental factors that are associated with faster or slower pit latrine fill-up rates. Using ordination of microbial community data, we observed a linear gradient in terms of beta diversity with increasing pit latrine sample depth, corresponding to a shift in microbial community structure from gut-associated families in the top layer to environmental- and wastewater-associated taxa at greater depths. We also investigated the bacteria and environmental parameters associated with fill-up rates, and identified pH, volatile solids, and volatile fatty acids as features strongly positively correlated with pit latrine fill-up rates, whereas phosphate was strongly negatively correlated with fill-up rate. A number of pit latrine microbiota taxa were also correlated with fill-up rates. Using a multivariate regression, we identified the Lactobacillaceae and Incertae_Sedis_XIII taxa as particularly strongly positively and negatively correlated with fill-up rate, respectively. This study therefore increases knowledge of the microbiota within pit latrines, and identifies potentially important bacteria and environmental variables associated with fill-up rates. These new insights may be useful for future studies investigating the decomposition process within pit latrines.

Original languageEnglish
Article number960747
JournalFrontiers in Microbiology
Volume13
DOIs
Publication statusPublished - 23 Sep 2022

Keywords

  • 16S rRNA gene sequencing
  • decomposition
  • microbiota
  • pit latrines
  • sanitation

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