Microbiological water quality monitoring in a resource-limited urban area: a study in Cameroon, Africa

In resource-limited developing nations, such as Cameroon, the expense of modern water-quality monitoring techniques is prohibitive to frequent water testing, as is done in the developed world. Inexpensive, shelf-stable 3M™ Petrifilm™ Escherichia coli/Coliform Count Plates potentially can provide significant opportunity for routine water-quality monitoring in the absence of infrastructure for state-of-the-art testing. We used shelf-stable E. coli/coliform culture plates to assess the water quality at twenty sampling sites in Kumbo, Cameroon. Culture results from treated and untreated sources were compared to modern bacterial DNA pyrosequencing methods using established bioinformatics and statistical tools. Petrifilms were reproducible between replicates and sampling dates. Additionally, cultivation on Petrifilms suggests that treatment by the Kumbo Water Authority (KWA) greatly improves water quality as compared with untreated river and rainwater. The majority of sequences detected were representative of common water and soil microbes, with a minority of sequences (<40%) identified as belonging to genera common in fecal matter and/or causes of human disease. Water sources had variable DNA sequence counts that correlated significantly with the culture count data and may therefore be a proxy for bacterial load. Although the KWA does not meet Western standards for water quality (less than one coliform per 100 mL), KWA piped water is safer than locally available alternative water sources such as river and rainwater. The culture-based technology described is easily transferrable to resource-limited areas and provides local water authorities with valuable microbiological safety information with potential to protect public health in developing nations.