Water borne diarrheal pathogens might accumulate in river water and cause contamination of drinking and irrigation water. The La Paz River basin, including the Choqueyapu River, flows through La Paz city in Bolivia where it is receiving sewage, and residues from inhabitants, hospitals, and industry. Using quantitative real-time PCR (qPCR), we determined the quantity and occurrence of diarrheagenic Escherichia coli (DEC), Salmonella enterica, Klebsiella pneumoniae, Shigella spp. and total enterobacteria in river water, downstream agricultural soil, and irrigated crops, during one year of sampling. The most abundant and frequently detected genes were gapA and eltB, indicating presence of enterobacteria and enterotoxigenic E. coli (ETEC) carrying the heat labile toxin, respectively. Pathogen levels in the samples were significantly positively associated with high water conductivity and low water temperature. In addition, a set of bacterial isolates from water, soil and crops were analyzed by PCR for presence of the genes bla CTX-M , bla KPC, bla NDM , bla VIM and bla OXA-48. Four isolates were found to be positive for bla CTX-M genes and whole genome sequencing identified them as E. coli and one Enterobacter cloacae. The E. coli isolates belonged to the emerging, globally disseminated, multi-resistant E. coli lineages ST648, ST410 and ST162. The results indicate not only a high potential risk of transmission of diarrheal diseases by the consumption of contaminated water and vegetables but also the possibility of antibiotic resistance transfer from the environment to the community.
Bibliographical noteFunding Information:
This work was supported by the Swedish International Development Cooperation Agency (Sida) to [VI and ÅS], and a Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS)/Swedish Water funded project on Risk-Based Decision Support for Safe Drinking Water [SWWA 13-102] to [ÅS]. The project is part of a Sweden-Bolivia Sida-Universidad Mayor de San Andres (UMSA) development program. JG-O acknowledges the financial support from the International Science Program (ISP). JB-P acknowledges financial support from FORMAS. The findings and conclusions contained in the article are those of the authors and do not necessarily reflect positions or policies of funder institutions. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We acknowledge Nataniel Mamani for his help during sampling events and Miguel Fernandez for his assistance during statistical analysis.
© 2019 Guzman-Otazo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.