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Advisor(s)
Abstract(s)
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 monitoring
tools of contaminant effects on different levels of biological integration since they are suspension
feeders that actively filter, retain and concentrate 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 strains isolated from freshwater bivalves, and (ii) determine their virulence
factors. Samples were collected in the middle sector of the Tua River. Isolates were retrieved in
Chromocult® Coliform Agar plates (Merck, Germany). Antimicrobial susceptibility testing
(AST) was done by the Kirby-Bauer disk diffusion method against 21 antimicrobial agents,
according to the recommendations issued by the EUCAST and CLSI. Antibiotic resistance rates
were ticarcillin (TIC) 87.5%, ticarcillin-clavulanic acid (TIM) 87.5%, piperacillin (PRL) 6.3%,
cefoxitin (FOX) 18.8%, tobramycin (TOB) 31.3%, gentamicin (CN) 12.5%, and amikacin (AK)
87.5%. Antibiotics whose antimicrobial resistance was 100% belong to β-lactam, namely
penicillins and carbapenems. The antimicrobial susceptibility test revealed that 43.75% of the
isolates were MDR. PCR-based assays were designed for phylogenetic E. coli groups evaluation.
The E. coli phylogenetic group D or E was the most prevalent (50%), followed by phylogenetic
groups E or clade I, B1 and A. Phylogenetic groups D or E and E or clade I should be confirmed
using E-specific primers. Our results indicated that bivalves provide an efficient, time-integrating
tool for identifying/quantifying faecal indicators, including multidrug resistant bacteria
Description
Keywords
Phylogenetic groups E. coli One Health
Citation
Gomes, Sónia; Piteira, Martinha; Fernandes, Conceição; Varandas, Simone; Saavedra, Maria José (2021). Escherichia coli Isolated from Potomida littoralis and Margaritifera margaritífera: phylogenetic group determination. In The European Congress of Malacological Societies 2021-Euromal 2021: book of abstracts. Praga
Publisher
Czech University of Life Sciences Prague