Phenotypic characterisation of Enterococcus spp. from femoral head necrosis lesions of chickens

摘要

Two types of Enterococcus species were isolated from femoral head necrosis lesions of chickens. A total of 150 femoral articular tissues, of which 121 were from commercial broilers, 18 from broiler breeders, and 11 from layer breeders, were sampled. Out of 48 Enterococcus isolates of these clinical samples, 37 and 11 isolates were identified as Enterococcus faecalis and Enterococcus faecium, respectively. Additionally, 42 (28%) Escherichia coli and 33 (22%) Staphylococcus aureus isolates were obtained either alone or together with 1 of the 2 Enterococcus species from the same clinical samples, while no bacteria were detected from the remaining 56 samples. None of the Enterococcus isolates showed gelatinase activity, while only 1 Enterococcus faecalis isolate was found to be positive for both aggregation substance and cytolysin production. Resistance rates to tetracycline, erythromycin, ciprofloxacin, chloramphenicol, and ampicillin in Enterococcus faecalis were 94.6%, 43.2%, 37.8%, 17.8%, and 2.8%,respectively, while they were 81.8%, 45.5%, 18.2%, 9.8%, and 9.8% for the Enterococcus faecium isolates. All of the Enterococcus isolates were susceptible to both vancomycin and gentamicin. Resistance rate to 3 or more antibiotics was 18.9% and 18.1% for Enterococcus faecalis and Enterococcus faecium isolates, respectively.