Detection and genetic analysis of Escherichia coli from Tonle Sap Lake and its tributaries in Cambodia: Spatial distribution, seasonal variation, pathogenicity, and antimicrobial resistance

Ichiro Yoneda; Ulya Nur Rozanah; Masateru Nishiyama; Hasika Mith; Toru Watanabe

doi:10.1016/j.envpol.2022.120406

Detection and genetic analysis of Escherichia coli from Tonle Sap Lake and its tributaries in Cambodia: Spatial distribution, seasonal variation, pathogenicity, and antimicrobial resistance

Environ Pollut. 2022 Dec 15:315:120406. doi: 10.1016/j.envpol.2022.120406. Epub 2022 Oct 14.

Authors

Ichiro Yoneda¹, Ulya Nur Rozanah², Masateru Nishiyama³, Hasika Mith⁴, Toru Watanabe³

Affiliations

¹ Department of Regional Environment Creation, United Graduate School of Agricultural Sciences, Iwate University, 18-8 Ueda 3-Chome, Morioka, 020-8850, Japan. Electronic address: u3321010@iwate-u.ac.jp.
² Department of Agricultural Microbiology, Faculty of Agriculture, Gadjah Mada University, Bulaksumur, Yogyakarta, 55281, Indonesia.
³ Department of Food, Life and Environmental Sciences, Faculty of Agriculture, Yamagata University, 1-23 Wakaba-Machi, Tsuruoka, 997-8555, Japan.
⁴ Faculty of Chemical and Food Engineering, Institute of Technology of Cambodia, Russian Federation Blvd., P.O. Box 86, Phnom Penh, 12156, Cambodia.

PMID: 36252883
DOI: 10.1016/j.envpol.2022.120406

Abstract

As an indicator of fecal contamination, Escherichia coli was monitored in Tonle Sap Lake, Cambodia, and its tributaries during low- and high-water seasons, focusing on the impacts on floating villagers inhabiting boathouses. E. coli concentrations in the floating villages (3.6 × 10³ and 5.7 × 10³ CFU/100 mL during the low- and high-water seasons, respectively) were significantly higher than those in other lake sites (4.0 × 10¹ and 7.0 × 10⁰ CFU/100 mL during the low- and high-water seasons, respectively) and rivers (3.3 × 10² and 8.9 × 10² CFU/100 mL during the low- and high-water seasons, respectively), most likely because fecal materials from the boathouses were discharged without treatment. At most of the lake sampling sites remote from the boathouses, the E. coli concentration was lower during the high-water season than that during the low-water season, due to dilution by lake water. E. coli colonies detected during monitoring were isolated for pathotyping, antimicrobial susceptibility testing, beta-lactamase gene detection, and multilocus sequencing typing (MLST). Of the 659 E. coli isolates, 101 (15.3%) were diarrheagenic E. coli (DEC). The prevalence of DEC (52.2%) in the floating villages during the low-water season was higher than that during the high-water season (4.2%) and that in other sites during both seasons (10.6-21.3%). The DEC isolates from the floating villages during the low-water season showed high antimicrobial resistance, including ampicillin (83.4%) and ciprofloxacin (83.4%), and frequently possessed a beta-lactamase gene (bla_TEM) (83.4%). MLST analysis indicated that the predominant sequence type (ST) of DEC isolates from the floating villages possibly originated from humans, whereas more diverse STs were detected in isolates from other sites. We revealed the wide presence of diarrheagenic and antimicrobial-resistant E. coli in Tonle Sap Lake and identified a considerable infection risk in floating villages, especially during the low-water season.

Keywords: Diarrheagenic Escherichia coli; ESBL genotypes; Fecal contamination; Floating village; Multilocus sequence typing; Tonle sap lake.

MeSH terms

Anti-Bacterial Agents / pharmacology
Cambodia / epidemiology
Drug Resistance, Bacterial / genetics
Escherichia coli
Escherichia coli Infections* / epidemiology
Humans
Lakes*
Multilocus Sequence Typing
Seasons
Virulence
Water
beta-Lactamases / genetics

Substances

Anti-Bacterial Agents
beta-Lactamases
Water