Antibiotic Resistance Pattern Of Escherichia Coli Isolated From Poultry In Bangalore

摘要

A total of 85 samples were collected from moribund birds with different pathological conditions like perihepatitis, enteritis, air sacculitis and pneumonia. In this investigation thirty two avian pathogenic Escherichia coli (APEC) strains isolated from broiler chickens with colisepticemia and examined for susceptibility to antimicrobials of veterinary and human significance. Serotyping of these isolates revealed 32 ‘O’ serotypes, predominantly O11, O79 and O111 accounting for 26.15 %. The percentage of other serotypes varied from 1.54-4.61 %. In vitro antibiotic activities of 20 antibiotic substances against the isolates were determined by disc diffusion test (Kirby Bauer method). Multiple resistances to antibiotics were observed in all the isolates. Antibiogram profiles indicated maximum resistance to Nitrofurazone (90.77 %), followed by tetracycline (83.08 %) & cotrimoxazole(76.92 %). High sensitivity to ciprocloxacin and enrofloxacin (83.08 %), chloramphenicol (81.54 %), pefloxacin (76.92 %) and norfloxacin (75.39 %) were noticed. Introduction Escherichia coli is one of the most important agent causing secondary bacterial infection in poultry and may also be a primary pathogen (Gross, 1994). Colibacillosis is the most frequently reported disease in surveys of poultry diseases or condemnations at processing (Saif, 2003). In the past few years, both the incidence and severity of colibacillosis have increased rapidly, and current trends indicate that it is likely to continue and become an even greater problem in the poultry industry (Altekruse et al., 2002). Antimicrobial therapy is an important tool in reducing both the incidence and mortality associated with avian colibacillosis (Freed et al., 1993). E. coli may be sensitive to many antibiotics. However, isolates of E. coli from poultry are frequently resistant to one or more antibiotics, especially if they have been widely used in poultry industry over a long period (e.g., tetracyclines) (Allan et al., 1993; Blanco et al., 1997). Antibiotics once effective at controlling E. coli infections are now ineffective due to the bacterium’s acquired resistance to these compounds. Resistance to two or more classes of antibiotics is now commonplace in both veterinary (Gonzalez and Blanco, 1989) and human (Dennesen et al., 1998) medicine.Concern has been expressed about possible harmful effects on humans through the use of drugs in agriculture, as follows: 1) increased microbial drug resistance, 2) drug residues in food, 3) allergic reactions and sensitisation to antimicrobials, and 4) drug toxicity (Bazile-Pham-Khac et al., 1996). Concern about antibiotic resistance and its transmission to human pathogens is important because these resistant bacteria may colonize the human intestinal tract and may also contribute resistance genes to human endogenous flora. The episomal transfer of resistance factor between the intestinal pathogens may lead to evolution of drug resistant bacterial strains in human being which is of public health importance (Tabatabaei and Nasirian, 2003). In view of the significance of E. coli infection in poultry, this study has been undertaken to isolate and to study their antibiotic drug resistance pattern Materials and Methods Collection of Samples: The tissues were collected based on clinical findings and pathogonomic lesions observed during detailed post mortem examination of poultry at Department of Pathology, Veterinary College, Bangalore; Poultry Disease Diagnostic Laboratory, Bangalore and Central Disease Investigation unit, IAH & VB, Bangalore, India. A total of 85 samples from 55 birds of 1-7 weeks of age were collected in sterile containers following aseptic precautions and transported to laboratory. Tissues were collected form cases exhibiting perihepatitis (31), enteritis (27), airsacculitis (5), yolk sac infection (7), pnemonitis (1) and pericarditis (14).Isolation and Identification: The tissue samples were plated on Mac Conkey agar (HIMEDIA) and incub