Isolation and characterization of bacteria associated with yolk sac infection (Omphalitis) in chicken from three hatcheries in Bishoftu, Ethiopia

A study was conducted from November 2014 to June 2015 at three hatcheries designated as A, D and E in Bishoftu Town, Ethiopia, to isolate and identify bacteria associated with yolk sac infection and to determine antimicrobial susceptibility profile of the predominant isolates. A total of 385 Lohmann and Koekoek breed, 1 to 7 days old chicks suffering from yolk sac infection were examined from three different hatcheries of which 96.1% (N=370) of them were showing unabsorbed yolk sac. All the chicks were necropsied and yolk sac samples were collected for isolation and identification of bacteria followed by testing of the isolates for their susceptibility to 11 antimicrobial agents using disc diffusion method. A total of 323 bacterial isolates were identified, of these Escherichia coli were the most common bacteria (N=116; 35.91%) isolated followed by Salmonella species (N=111; 34.36%) and Staphylococcus aureus (N=96; 29.72%). Significant difference (P<0.001) was noted among the hatcheries on the frequency of isolation of the predominant bacteria species from yolk sac samples with the highest rate of isolation being in hatchery A. All the tested predominant bacterial isolates showed higher susceptibility to Gentamicin, Chloramphenicol, Amikacin (except S. aureus) and Kanamycin but were resistant to Ciprofloxacin, (except S. aureus), Penicillin G, Tetracycline, Sulfamethoxazole  and Amoxicillin (except S. aureus). The existence of multi-drug resistant bacteria isolates associated with yolk sac infection suggests that more emphasis should be given towards preventing omphalitis in chicks through improvements of sanitary measures at hatcheries than to use antimicrobials to control infections.   Key words:  Bacteria, chicken, yolk sac infection, antimicrobial sensitivity, Ethiopia.