Phylogenetic and molecular characterization of extended spectrum betalactamase producing E. coli isolated from human, animal fecal carriage and effluent water sources in Dschang town

Abstract

Background: Escherichia coli is a versatile bacterial species, principally
present in the mammalian gut microbiome, gut microbiomes of birds, reptiles
and fish, in soil, water, plants, and food. There are eight phylo-groups of E. coli,
with seven belonging to E. coli sensu stricto (A, B1, B2, C, D, E, F) and one
corresponding to Escherichia clade I. The dissemination of antibiotic resistance
in Escherichia coli is a significant threat to public health worldwide and the
production of Beta-lactamase enzymes is the major cause of E. coli resistance.
ESBLs confer resistance to oxyiminocephalosporins, and often express a
multidrug-resistant phenotype, leaving only limited therapeutic options
Extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC). The
lower digestive tract of colonized patients has been recognized as the major
source of ESBL producing organism. Fecal colonization with ESBL-EC is
associated with infection in healthy individual. The aim of this study was to
determine the phylogenetic group of the ESBL producing E. coli and to
characterize the Antibiotic resistance genes (bla CTX-M, bla SHV and bla TEM)
of E. coli isolates from humans, animals and water in Dschang.
Methods: We collected ESBL-Ec isolates from humans, livestock and effluents
between January 2023 and November 2023 in Dschang community. Polymerase
chain reaction was performed for the detection of the phylogenetic group and
the detection of resistance genes (bla TEM, bla CTX-M and bla SHV).
Results: Phenotypic analysis of these ESBL-producing strains revealed
resistance associated with other antibiotic families. In the case of strains of
human origin, 17% of E. coli ESBL were resistant to at least one quinolone and
one aminoglycoside, 12% were resistant to both a quinolone and a carbapenem,
and 13% were resistant to at least one antibiotic from all three families. For
strains of animal origin, combined resistance to aminoglycosides and
quinolones was noted in 28.57% of these strains. Subsequently, 139 E. coli ESBL
strains were analyzed for beta-lactam resistance genes (102 strains from
humans, 33 from livestock and 4 from effluents). bla SHV was present in 40% of
strains, bla TEM in 37%, bla CTX-M in 6%, bla SHV and TEM simultaneously in
10% of the isolates. Majority of strains isolated in the human sector belonged to
phylogenetic group B1 and possessed bla SHV and bla TEM genes. phylogroup
B2 was found in humans (8.3%), hens (5.2%) and beef (10%).
Conclusion: The beta-lactam resistance genes found most in the E. coli ESBL
strains in our study were bla TEM and bla SHV in humans, animals and effluent water. In terms of phylogenetic groups, the majority of strains belonged to
groups B1 and A, with a few strains of phylogroup B2 present in humans and
animals. These results highlight the role of Escherichia. coli ESBL from digestive
carriage and effluent water in the dissemination of antibiotic resistance genes
in the community