Antibiotic Resistance Pattern and Phylogenetic Analysis of Commensal Escherichia coli Isolated from Poultry

摘要

In the present investigation a total of 40 isolates of Escherichia coli from healthy poultry birds were investigated for antibiotic resistance pattern and distribution of various phylogroups in different age groups of birds. All the isolates showed green metallic sheen on Eosin Methylene Blue agar plate and were confirmed by various biochemical test. Genotypic confirmation by 16S rRNA gene revealed an amplicon of 662bp in all Escherichia coli isolates. The antibiogram pattern showed high distributionof resistance to multiple drugs among all the isolates with at least each isolate being resistant to three or more antibiotics. The antibiogram results showed that 100% of the isolates were resistant to penicillin, oxacillin and nalidixic acid. Resistance level was more than 50% for doxycycline (97.5), tetracycline (90%), erythromycin (85%), rifampicin (80%) and trimethoprim (75%). The study revealed that amikacin and levofloxacin were the most effective drugs. Out of the four main phylogenetic groups(A, Bl, B2, and D), only two phylogroups viz A and Bl were obtained by multiplex PCR with a prevalence of 62.5% and 37.5% respectively.