Objectives: The aim of this research was to examine the extent of antibiotic resistance among bacterial isolates from unhealthy broiler chickens in Shiraz area.
Animals: two hundred broiler chickens.
Procedure: First, bacterial agents were isolated from chickens. After identification, their drug resistance pattern was studied using impregnated filter paper disc diffusion method.
Statistic analysis: Descriptive study.
Results: Eschirichia coli, Salmonella and Staphylococcus aureus were isolated with incidence rates of 82, 16.5, and 1.5%, respectively. Among antibiotics used in the antibiogram (penicillin G, ampicillin, gentamicin, furazolidone, chloramphenicol, tylosin, enrofloxacin, tetracycline, lincospectin, flumequine, and erythromycin), the highest and the lowest rate of drug resistance were shown to be against penicillin G and gentamicin, respectively. In addition, Eschirichia coli exhibited a higher degree of antibiotic resistance compared with the other two microorganisms. Moreover, all the bacterial isolates were resistant to at least one antibiotic, and 12%
of coliforms were sensitive to one antibiotic. Salmonella isolates were sensitive to 3, but resistant to 8 antibiotics. Staphylococci showed sensitivity to 6, but resistance to 5 antimicrobial agents. Conclusion: Results of the present study indicate a high incidence of antibiotic resistance among bacterial agents isolated from chickens
which can be attributed to the incorrect use of antibiotics in poultry industry. J. Fac. Vet. Med. Univ. Tehran. 58, 3: 223-226, 2003