Title : Pheno- and genotypic characterization of Enterococcus spp. isolated from the animal farm environments
Abstract:
Bacteria of the Enterococcus genus are opportunistic microorganisms widely prevalent in the environment. An important source of pathogenic strains of Enterococcus spp. are farm animals and their living environment. Enterococcus faecium and Enterococcus faecalis species are most often responsible for causing infections in humans. Increased antibiotic resistance of strains is often associated with the presence of various virulence factors.
The aim of this study was the assessment of drug susceptibility of Enterococcus spp. isolates from livestock farming environment and the frequency of genes encoding selected virulence factors (VFs).
Material for the study consisted of 364 isolates Enterococcus spp. strains from the pig (200, 54.9%), poultry (132; 36.3%) and cattle (32; 8.8%) husbandry environment in the form of swabs and faeces. Species identification of obtained strains was performed using MALDI- TOF MS technique. Antibiotic susceptibility of isolates was assessed by disc diffusion method according to the EUCAST v. 14.0 recommendation. The study evaluated the presence of the selected VFs genes (ebpABC, pil, efaAfs and gelE) was made using PCR method for 40 strains E. faecalis and E. faecium isolated from poultry farm.
The isolated strains belonged to 8 species of Enterococcus spp. with the highest frequency: E. hirae - 144 (39.6%), E. faecium - 120 (33.0%) and E. faecalis - 77 (21.2%). Evaluation of drug susceptibility showed that 279 (76.6%) of the strains were resistant to at least one antibiotic. The highest number of strains showed resistance to streptomycin (n=199, 54.7%). The lowest percentage of resistance was reported for teicoplanin (n=3, 0.8%). Also, high-level aminoglycoside resistance (HLAR) was detected in 6.04% of E. faecalis strains. One vancomycin-resistant E. faecium strain was detected. The study showed the presence of multidrug - resistant (MDR) (103; 28.3%) and extensively drug resistant (XDR) (9; 2.5%) strains.
The presence of selected virulence genes was found in 6 isolated strains among 40 tested. Five represented E. faecalis species, and one E. faecium. The study found one strain of E. faecalis carrying all VFs genes included in the study.
The irrational use of antibiotics in agriculture and veterinary practice is considered to be one of the key reasons for the rapid spread of antibiotic resistance among microorganisms. Owing to the fact that farm environments can be a reservoir of antimicrobial resistance and transmission route of antimicrobial resistance genes from commensal zoonotic bacteria to clinical strains, it is of a great importance to public health to monitor trends in this research area.
