Isolation, Molecular Characterization and Geoprocessing of Enteropathogenic, Enterotoxigenic, and Shiga Toxin-Producing Escherichia coli in Drinking Water Sources from Southeast Brazil

Abstract

In Brazil, safe drinking water is not widely available, and consequently waterborne diseases are still associated with high morbidity and mortality rates. Among waterborne bacteria, diarrheagenic Escherichia coli (DEC) should be highlighted. This study targeted the evaluation of enteropathogenic (EPEC), enterotoxigenic (ETEC), and shiga toxin-producing (STEC)/enterohemorrhagic Escherichia coli in drinking water in Southeast Brazil and the georeferencing of generated data. A total of 1185 water samples were studied. Among them 7.8% and 4.1% gave positive results for total and fecal coliforms, respectively. By employing PCR, a total of 12 diarrheagenic E. coli (DEC) isolates (6 ETEC, 4 STEC, and 2 EPEC) from eight water samples (4, 2, and 2 positives for STEC, ETEC, and EPEC, respectively) were detected including samples collected in schools and a healthcare facility where particularly susceptible hosts are found. Data generated were submitted to georeferencing. A positive correlation (r2 = 0.9) between DEC detection and the rainy period was observed. The presence of DEC in drinking water samples in the studied municipalities highlights the relevance of controlling the sources of human and animal fecal pollution, as well as the management of municipal wastewater sources in order to reduce potential risks to human health. Searching for DEC and georeferencing DEC positive sites may subsidize the proposal of corrective and preventive actions by environmental surveillance agencies.