Isolation, histopathology and antibiogram of Escherichia coli from pigeons (Columba livia)

Aim: To know the prevalence of antibiotic resistant Escherichia coli among dead and/or diarrhoic pigeons in and around greater Guwahati. Materials and Methods: Samples were cultured from dead and/or diarrhoic pigeons and identification was done by standard methods. The sensitivity of the isolated E.coli strains to 15 antibiotics of human and veterinary use was also determined. Organs from those dead birds from which E.coli were recovered were processed according to the routine procedure for histopathological studies. Results: Out of 150 pigeons subjected to microbiological investigation, 91(60.67 %) samples were found positive for E. coli. The most frequently occurring serotypes were O157 (9.89%), followed by O68, O121 (7.69%), O9, O75, O131 (5.49%), O2, O13, O22 (3.30%). Antibiogram investigation of the isolates revealed that 91isolates (100%) exhibited resistance against Ampicillin followed by Nitro-furantoin (73.62%), Tetracycline (65.93 %), Oxytetracycline (62.63 %) and Streptomycin (61.54). Gross changes of some birds showed fibrinous pericarditis and perihepatitis and coligranuloma in different organs like liver and serosal surface of intestine. Microscopically, severe congestion and haemorrhages in different organs such as liver, kidney, lung and intestine. In some cases thick layer of fibrinous exudates with large number of heterophills over the surface of liver and heart with early degenerative changes as well as focal necrosis. Conclusion: The result of this study suggests that antimicrobial-resistant pathogenic E.coli is present in pigeons in and around greater Guwahati. Surveillance programs may be introduced to monitor antimicrobial resistance of pathogenic E.coli in pigeons in and around greater guwahati.