Diarrheal bacterial pathogens and multi-resistant enterobacteria in the Choqueyapu River in La Paz, Bolivia.

Jessica Guzman-Otazo,Violeta Poma,Lucia Gonzales-Siles,Carl-Fredrik Flach,Johan Bengtsson-Palme,Kaisa Thorell,Åsa Sjöling,Volga Iñiguez,Jesse Goodman

doi:10.1371/journal.pone.0210735

Abstract

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 blaCTX-M, blaKPC, blaNDM, blaVIM and blaOXA-48. Four isolates were found to be positive for blaCTX-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.

Highlights

Diarrheal diseases are a major cause of morbidity and mortality worldwide with particular impact on children [1, 2]
The samples were investigated for the presence of different categories of diarrheagenic E. coli (enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enterohaemorhagic E. coli (EHEC) and enteroinvasive E. coli (EIEC)), K. pneumoniae, S. enterica and Shigella spp. by targeting signature genes (Table 1)
Bacteria positive for Glyceraldehyde 3-phosphate dehydrogenase-A (gapA) were detected in 100% of river water samples and was the most abundant gene detected, followed by the gene encoding the Enterotoxigenic Escherichia coli (ETEC) heat labile toxin B chain (Fig 1)

Summary

Introduction

Diarrheal diseases are a major cause of morbidity and mortality worldwide with particular impact on children [1, 2]. The project is part of a Sweden-Bolivia SidaUniversidad Mayor de San Andres (UMSA) development program. 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

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