Bacterial contamination of dead-in-shell embryos in ostrich hatcheries and antimicrobial resistance patterns of isolated Escherichia coli

The bacterial contamination of fertile eggs is the most common cause of embryonic death in ostrich hatchery units leading to financial loss in ostrich industry. The aim of this research was to investigate the bacterial contamination status, with emphasis on Escherichia coli, of ostrich hatcheries and the antimicrobial resistance profile of isolated Escherichia coli. Atotal of 120 ostrich eggs with dead embryos, at weekly intervals, were collected from three ostrich hatcheries. The dead embryos were sent to laboratory and samples were collected aseptically from different organs. Bacterial detection and identification were performed by using standard bacteriological and biochemical techniques. Antimicrobial susceptibility test was carried out by agar diskdiffusion method against 27 antimicrobial agents. Different types of bacteria were isolated from 56 eggs (46.7%). Twenty-four ostrich eggs were shown to carry E. coli. In some eggs, in addition to yolk sac, E. coli was also isolated from meconium, liver, or heart blood which increased the total number of E. coli isolates to 32. All E. coli isolates were susceptible to trimethoprim + sulphamethoxazole, danofloxacin, and flumequine, whereas all were resistant to carbenicillin and erythromycin. Resistance to other agents was variable. Multi-drug resistance pattern was found among all E. coli isolates and included 2 to 12 drugs. Thirty-two E. coli isolates generated 30 different resistance profiles against 27 antimicrobial drugs. This was the first comprehensive report regarding the bacterial, particularly Escherichia coli, contamination of dead-in-shell ostrich embryos and antimicrobial resistance status of the Escherichia coli isolates from ostrich eggs in Iran.