Species distribution and antimicrobial susceptibility of enterococci isolated from broilers infected experimentally with eimeria spp and fed with diets containing different supplements

Abstract

Resistant bacteria in animal can be spread to environment and to humans. Poultry feed and infections causedby Eimeria spp. are important factors in determining the intestinal microbial communities. The aim of thisstudy was to verify the prevalence of species and antimicrobial susceptibility of Enterococcus isolated frombroilers fed with different supplements and infected experimentally with Eimeria spp. Broilers were dividedin eight groups, fed with diets supplemented with a combination of antimicrobial, ionophore-coccidiostatics,probiotic, essential oil. At 14 days old all birds, except the control, received a solution containing oocysts ofEimeria spp. Samples of cloacal swabs from broilers were collected. A total of 240 Enterococcus sp. strainswere isolated, confirmed genus by PCR, classified as species, tested for antimicrobial susceptibility andscreened by PCR for the presence of tet(L), tet(M) and erm(B) genes. The overall distribution of speciesisolated from fecal samples was E. faecalis (40%), followed by E. casseliflavus/E. gallinarum (10.8%), E.mundtii (10.8%), E. faecium (10.8%), E. columbae (5.8%) and E. gallinarum (4.2%). Changes in thecomposition or frequency of Enterococcus species were observed in all dietary supplementation.Antimicrobial susceptibility tests showed resistance phenotypes a range of antibiotics, especially used inhumans such as, streptomycin, penicillin, rifampicin and vancomycin. There was no correlation betweendifferent supplementation for broilers and antimicrobial resistance and the presence of tet(M), tet(L) anderm(B) genes. Dietary supplementation had effect on the Enterococcus sp. colonization, but did not havesignificant effect on the phenotype and genotype of antimicrobial resistance in enterococci.