An Investigation into Enterobacteriaceae Responsible for Early Mortality in Japanese Quail Chicks and Their Antibiotic Susceptibility Patterns

Quail is an alternative source of protein for humans. These birds can be affected by common bacterial infections. Bacterial contamination of egg is the most common cause of mortality in Japanese quail chicks. In order to study the role of some members of Enterobacteriaceae responsible for early mortality in Japanese quail chicks, 100 dead or moribund quail chicks were obtained from 10 different farms in Ahvaz, Iran. Samples were taken from the liver and yolk sac of the birds and bacterial isolation from samples was conducted by streaking them on MacConkey, Brilliant Green, Salmonella-Shigella and Xylose Lysine Deoxycholate agar plates. The plates were incubated at 37 °C for 24-48 hours, and by standard biochemical tests bacterial isolates were identified. Final confirmation of Salmonella serotypes was performed by Razi Institute. All the isolates were examined for susceptibility to 12 different antibiotics (Padtan-Teb Co., Tehran, Iran) by the disk diffusion (Kirby Bauer) method. The results showed that 78% of the quail chicks were infected. The isolated bacteria were Escherichia coli (44%), Klebsiella pneumonia (8%), Salmonella serovar ruzizi (5%), Salmonella serovar typhimurium (3%), Enterobacter cloacae (4%), Enterobacter aerogenes (4%), Proteus vulgaris (5%) and Proteus mirabilis (5%). One hundred percent susceptibility was observed to gentamycin, soltrim, tetracycline, fosfomycin, florfenicol, cephalexin and ceftriaxone. E. coli isolates were susceptible to soltrim and ceftriaxone, Salmonella isolates were susceptible to fosfomycin, Enterobacter isolates were susceptible to ceftriaxone and Proteus and Klebsiella isolates showed susceptibility to ceftriaxone. It is concluded that the members of Enterobacteriaceae family, specifically the genera Escherichia and Salmonella, are the major causes of early mortality in newly-hatched Japanese quail chicks.