The rate of Salmonella and Escherichia coli isolations from broiler breeder flocks in various provinces of Iran

Salmonella and Escherichia coli (E. coli) are among the most important agents causing bacterial infections in commercial poultry flocks. Based on samples received from broiler breeder flocks, in this survey, the infection rate of these flocks to Salmonella and E. coli was evaluated. For this purpose, during 2010-2012, samples received from un-hatched eggs and day-old chicks of 28 and 132 broiler breeder flocks, respectively, from six province of Iran including East Azarbaijan, West Azarbaijan, Zanjan, Kermanshah, Gilan and Mazandaran were cultured for isolation of Salmonella and E. coli. In total, from 160 sampled flocks, 54 (33.75%) and 88 (55%) flocks were infected to Salmonella and E. coli, respectively. From egg samples, Salmonella and E. coli were isolated from 4 (14.28%) and 7 (25%) flocks, respectively. However, day-old chicks cultures resulted in isolation of Salmonella and E. coli from 50 (37.87%) and 81 (61.36%) flocks, respectively. Among 50 Salmonella isolates from day-old chicks, serogroups B and D were identified in 4 (8%) and 46 (92%) cases, respectively. In antimicrobial resistance test on bacterial isolates form day-old chicks, the highest resistance among Salmonella and E. coli isolates was found to sulfamethoxazol+trimethoprim (16%) and Fosomix® (70.37%), respectively. Imprudent use of various antibacterial agents in poultry flocks leads to increased antimicrobial resistance that is important for public health.