eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-04-16 6 1 277 280 8170 article B. S. Chaithra 1 Y. Hari Babu 1 S. Venkateshwar 2 M. Narsi Reddy 2 Department of Veterinary Microbiology, Veterinary College, Bidar - 585 401 (India). Centre for Biotechnology, University College of Technology, Osmania University, Hyderabad - 500 007 (India). Bacteriophage to an Escherichia coli isolate that is pathogenic in poultry was isolated from faecal samples of chickens. A study was conducted to evaluate the therapeutic efficacy of bacteriophage and the antibiotic enrofloxacin individually and in combination to treat colibacillosis.The experimental design was made with ten chickens each in five groups. The group I as control, unchallenged with E.coli, group II as challenged with E. coli, group III with E.coli and bacteriophage inoculations, group IV with E.coli and antibiotic (enrofloxacin), while the group V with combination of E.coli, bacteriophage and enrofloxacin. Birds in the group II were challenged at 7th day of age by injecting 105 cfu/ml of E.coli into the thoracic air sac. The antibiotic treatment was initiated immediately after the birds were challenged and consisted of 50 ppm enrofloxacin in the drinking water for 7 consecutive days. The bacteriophage treatment consisted of intramuscular injection of bacteriophage (1010pfu/ml) for 3 days administered immediately after the E.coli challenge. Mortality in the birds challenged with E.coli and untreated was 60% and the bacteriophage treatment significantly decreased mortality to 10 %. In the antibiotic treatment group morbidity was seen in only one bird and there was no mortality. The results indicated the effectiveness of bacteriophage treatment. Though the combination of bacteriophage with antibiotic (enrofloxacin) showed equal results, it was suggested that better usage of bacteriophage in treating colibacillosis as it lacks side effects that regularly been envisaged through the antibiotic therapy. https://www.biotech-asia.org/vol6no1/study-on-the-therapeutic-efficacy-of-isolated-bacteriophage-on-experimentally-induced-escherichia-coli-infection-in-chickens/ E.coli; Bacteriophage; enrofloxacin; poultry; antibiotic therapy