Do wildlife omnivores and herbivores serve as a source of
multidrug-resistant and pathogenic Escherichia coli strains in Poland?
Analysis with reference to the host species range
Abstract
The phenomenon of resistance of Escherichia coli strains in free-living
animals has been constantly expanding in recent years. However, the data
is still fragmented and, due to the growing threat to public health,
there is a constant need to search for and analyse new reservoirs and
indicate their role and importance in the circulation of resistance
genes. Therefore, the target group in this study were free-living
non-predatory animals as reservoirs of drug-resistant and potentially
virulent E. coli strains. For isolation, we used a combination of
selective media with four antimicrobials. After additional two-stage
analysis of strain similarity, we obtained 70 different isolates,
including 71.4% of multidrug-resistant strains. In strains isolated
from all species of animals, we determined high resistance to ampicillin
(95.7%), tetracycline (64.3%), streptomycin (51.4%), and
chloramphenicol (38.6%). Every third of the E. coli-positive individual
was a carrier of more than one resistant clone. Moreover, four isolates
among the resistant strains had the ExPEC pathotype, two had the ETEC
pathotype, and another two represented EHEC. Our study confirmed that
not only free-living predatory animals are reservoirs of resistance but
also many synanthropic species of herbivores and omnivores contribute
substantially to the spread of resistant and virulent E. coli strains.