Pharmacokinetics of ceftriaxone-tazobactam (8:1) combination in healthy and Escherichia coli induced diarrhoeic birds.

Antibiotic-resistant Escherichia coli infection of poultry causes significant economic losses. Extended spectrum β lactamases (ESBL) producing E. coli was inoculated in a broiler, Rhode Island Red and Haringhata Black birds orally at 56×10⁸ c.f.u. mL^-1 for induction of diarrhoea. Pharmacokinetics of ceftriaxone-tazobactam combination (8:1) was studied following a single intramuscular injection at 28.125 mg kg^-1 and the combination was administered twice daily to treat such infection. Plasma concentration of both ceftriaxone persisted up to 8 h in experimental birds and maintained an approximate ratio of 8:1 with tazobactam for a period of 2 h, 0.25 h and 0.75 h, respectively in a broiler, Rhode Island Red and Haringhata Black birds. The K _el was significantly lower in all experimental birds compared to healthy birds. Efficacy study was conducted in diarrhoeic birds by administration of ceftriaxone-tazobactam combination at 28.125 mg kg^-1 body weight twice daily intramuscularly for three days which caused an increase in specific antibody titre in the broiler on 5^th day and in Rhode Island Red birds 10^th day. However, Haringhata black birds were inherently showed more resistance towards the infection. The combination of ceftriaxone and tazobactam in the ratio of 8:1 can be an effective treatment to combat ESBL producing E. coli infections.