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

Published version
Peer-reviewed

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Authors

Ijaz, Umer Zeeshan 
Gundogdu, Ozan 
Keating, Ciara 
van Eekert, Miriam 
Gibson, Walter 

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.

Description

Peer reviewed: True


Acknowledgements: We would like to thank all the field and laboratory teams and to all the pit latrine owners who participated in this study. We also thank Paul Scott, Richard Rance and members of the Wellcome Sanger Institute's 454 sequencing team for generating 16S rRNA gene data.

Keywords

Microbiology, sanitation, microbiota, 16S rRNA gene sequencing, pit latrines, decomposition

Journal Title

Front Microbiol

Conference Name

Journal ISSN

1664-302X
1664-302X

Volume Title

Publisher

Frontiers Media SA