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 3MTM PetrifilmTM 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. Introduction In 2004, the World Health Organization (WHO) estimated that 2.2 million people die annually from diarrheal diseases, representing 3.7% of global mortality.1 Most of these deaths are due to preventable waterborne illnesses that occur in developing nations because of inadequate sanitation. Consequently, developed countries such as the United States and Canada sponsor improved sanitation water projects that are designed to lessen the risk of waterborne illnesses. However, one weakness of such water projects is the limited financial and technical involvement of developed nations after water projects are completed. As privatization replaces government subsidization, water authorities in developing countries often must shift to a user fee-based system. Billing residents for purified water presents a challenge because many citizens are either unable or unwilling to pay for public services such as improved drinking water.2 Furthermore, booming populations and urban influx place greater strain on existing infrastructure, explaining in part why the proportion of Africans with access to clean water has not increased since 1990.3 Therefore, water authorities typically must operate on highly conservative budgets unless supported by outside funding. Low operating budgets often result in compromised water treatment and reduced ancillary services such as water quality monitoring. Thus, the efficacy and sustainability of improved public water works in developing nations is questionable. In this study we evaluated the efficacy of a low-cost, technically simple bacteriological water quality test, with the hope of facilitating more frequent monitoring in a resource-limited area. The site of this study was Kumbo, Cameroon, a small city in Sub-Saharan West Africa (Figure 1). In 1968, with a population of less than 13,000, the city received assistance from the Canadian government to construct a drinking water treatment facility.4,5 Since completion in 1970, the operating entity has changed several times, but today the Kumbo Water Authority (KWA) manages the treatment facility with support from the Kumbo City Council. Although the distribution network has greatly expanded in recent years (currently delivering >280,000 m3 per year), the treatment facility has experienced few upgrades since 1970. Now, with more than 100,000 residents, the KWA cannot meet the demand. Water shortages are not uncommon.6 Furthermore, the original asbestos cement water mains are deteriorating and must be replaced with relatively expensive PVC pipes. Due to salaries, maintenance and chemical costs, the KWA can only afford to monitor biannually for ions, heavy metals, and microbiological agents, at a cost of approximately 600 USD per sampling event.7 Water samples are shipped to the nearest equipped laboratory in Mutangene, Cameroon at a distance of 400km (8+ h by car). Furthermore, the KWA has little control over how the samples are handled in transit or how quickly the results are processed. At a sampling frequency of twice per year, the city cannot make informed decisions on the safety of supplied water. In a Correspondence: Daniel N. Frank, Division of Infectious Diseases, School of Medicine and Microbiome Research Consortium, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave, MS B168 Bldg P15, Aurora, CO USA 80045. Tel: + 1.303.724.5536 Fax: +1.303.724.4926. E-mail: [email protected]