Phenotypic and Genotypic Antibiotic Resistance and Virulence Profiling of Enterococcus faecalis Isolated from Poultry at Two Major Districts in Bangladesh

The current study focuses on phenotypic and genotypic antimicrobial tolerance and virulence of Enterococcus faecalis (EF) isolated from poultry in Bangladesh Total 136 cloacal swab samples were collected randomly from meat and egg-producing poultry and analyzed for E. faecalis. The overall presence of E. faecalis was 21.3% (n=29) where 34.5% commercial broiler (CB) (n=10), 51.7% commercial layer (CL) (n=15) and 13.8% broiler breeder (BB) (n=04) were infected. Among 13 tested antibiotics, the highest resistance was found to penicillin G (100%), followed by streptomycin and tetracycline (97%). However, only imipenem showed high sensitivity (86%) with zero resistance. A significant level of multi-drug resistant (MDR) and possible-extremely drug resistant (XDR) have been observed among 66.52 and 20.69% isolates respectively. The highest MIC values (MIC50/MIC90) were observed for sulfamethoxazole and chloramphenicol (>= 1024/>= 1024), while only gentamicin showed satisfactory efficiency against E. faecalis (<= 1/16). Phenotypically vancomycin-resistant isolates were found to carry vanC(2) and vanA genes but the vanB gene was found only among the intermediate isolates. There was a correlation between vanA, vanB and vanC2 genes with virulence genes (gelE, cpd and asa1). Increased level of sequence similarity of multi-drug resistant isolates with Asian and European virulent strains were observed. To our knowledge, this is the first time report on genotypic vancomycin and linezolid resistance in poultry in Bangladesh. This study indicated that multiple antibiotic-resistant E. faecalis strains isolated from the poultry of the study areas in Bangladesh could be a possible source for disseminating antibiotic resistance and regarded as a severe threat to public health.