Antibiotic-Resistant Escherichia coli on Asian clam (Bivalvia, Corbiculidea): Case Study in the Tua River, Portugal.
Conference Paper
Overview
Research
Additional Document Info
View All
Overview
abstract
Antimicrobial resistance (AMR) is a major global health problem. Water use by human activities
represent a natural reservoir of AMR, thus a time-integrated approach is required in aquatic
ecosystems. Freshwater bivalves are widely applied as accumulation indicators and monitors of
contaminant effects on different levels of biological integration once they are suspension feeders
that actively filter, retain and concentrates particles from their surrounding water, including free
living or particle-bound bacteria. In this study, we aimed to (i) investigate the genetic diversity of
E. coli, (ii) determine the virulence factors of E. coli isolates, and (iii) detect antibiotic resistant
E. coli. Samples were collected in the middle sector of the Tua River. Isolates were retrieved in
Chromocult® Coliform Agar plates (Merck, Germany). Susceptibility testing was performed by
the disc diffusion method, according to the Clinical Laboratory Standards Institute (CLSI), and
the screening of phenotypic ESBL production was carried out by the double disk synergy test
using cefotaxime (30μg), ceftazidime (30μg), and amoxicillin/clavulanate (20/10μg) acid discs.
PCR-based assays were designed for phylogenetic E. coli groups evaluation, resistance and
detection of ESBL genes. The E. coli phylogenetic group B1 was the most prevalent (44 %),
followed by phylogenetic groups A and D. Phylogenetic groups A and B1 comprised more than
half (70 %) of the total E. coli isolated. Our results show that Corbicula spp. provide an efficient,
time-integrating tool for identifying/quantifying faecal indicators, including multidrug resistant
bacteria.
This work is supported by National Funds by FCT - Portuguese Foundation
for Science and Technology, under the project UIDB/04033/2020 and the I&D project
FRESHCO-Multiple implications of invasive species on Freshwater Mussel co-extinction
processes (PTDC/AGR-FOR/1627/2014-04/SAICT/2015).
