A study on bacterial flora and antibacterial resistance of yolk sac infection in Japanese quail (Coturnix japonica)

In order to study Enterobacteriaceae contamination of dead-in-shell embryos in quails and the antibacterial resistance of isolated salmonellae, 335 quail eggs which did not have external piping during the hatching period were transferred to the microbiology laboratory. Swab samples were collected from the interior contents of individual eggs, and the swabs were inoculated into tryptic soy broths (TSB) and selenite-F broths in groups of five swabs in each media. All cultured media were incubated at 37 °C. After 24 h, the TSB cultures were streaked on MacConkey agars, but cultures in selenite-F were subcultured on Salmonella–Shigella agars. After 24–48 h incubation of the solid media, the plates were observed for colony formation. Identification of the isolated bacteria was performed using standard bacteriological and biochemical procedures. Final confirmation of Salmonella in the isolates was undertaken using the slide serum agglutination test. Disc diffusion test on Muller–Hinton agar was used to determine the sensitivity of salmonellae isolates to antibacterial agents. Bacterial cultures of unhatched quail eggs showed 15.8 % contamination with Enterobacteriaceae. The isolation rate of Salmonella spp. from the unhatched quail eggs was 2.98 %. With respect to resistance of antimicrobial agents to Salmonella spp., all of the 10 antibiotics used (ampicillin, colistin, cephalexin, ciprofloxacin, chloramphenicol, gentamycin, furazolidone, nalidixic acid, norfloxacin and tetracycline) showed 100 % susceptibility to gentamycin. Drug resistance to ampicillin, colistin, cephalexin, ciprofloxacin, chloramphenicol, nalidixic acid and tetracycline were 80, 10, 50, 10, 40, 80 and 80 %, respectively. There were no observed drug resistance among the salmonellae isolates to gentamycin, furazolidone and norfloxacin.