Infectious coryza (IC), caused by Avibacterium paragallinarum, is one of the major problem affecting the commercial poultry industry worldwide including India. Very few reports regarding the prevalence of Av. paragallinarum in particular with the application of rapid, sensitive and confirmatory detection by the molecular tools are available from India. In this study a total of 105 field samples collected as nasal and sinus swabs from suspected cases of IC from different geographical locations viz. Bareilly (U.P), Pune (Maharashtra), Bangalore (Karnataka), Indore and Jabalpur (Madhya Pradesh) of India were analyzed. Cultural isolation revealed the presence of four different, NAD-dependent types of Av. paragallinarum positive isolates showing typical ‘satellite’ growth. Biochemically, all the isolates of Av. paragallinarum showed negative catalase activity, reduced nitrate to nitrite and unable to produce indole, hydrolysed the urea and fermented glucose and fructose without formation of gas and variability in acid production was observed with mannitol, mannose, and sorbitol. Antibiogram indicated that all field isolates were sensitive to Amoxycillin / Clavulanic acid, Enroflaxacin, Ciprofloxacin, Pefloxacin, Co-Trimoxazole and Chloramphenicol antibiotics. Furthermore, isolates were relatively less sensitive to Neomycin, Cephalaxin, Streptomycin and Furozolidin and resistant to Colistin, Ampicillin, Tetracycline, Oxytetracycline and Doxycycline antibiotics. PCR assay was standardized for direct detection of the causative bacterium on nasal and sinus swabs, culturally isolated colonies of Av. paragallinarum and reference strains by using combination of N1/R1 primers (HPG-2 gene based PCR) for evaluating the detection applicability of molecular diagnostic methodology. In conclusion, Av. paragallinarum was culturally isolated and biochemically characterized from field cases suspected of infectious coryza in poultry and presence of the causative bacterium was also confirmed by the molecular tool of PCR. Comparatively, PCR was found to be more effective and a sensitive diagnostic tool for rapid and reliable diagnosis of IC. Further, large scale epidemiological studies along with application of diagnostic molecular tools are suggested to know the real magnitude of this important pathogen affecting poultry flocks of the country.
Avibacterium paragallinarum, infectious coryza, poultry, isolation, antibiogram, PCR
Share This Article
© The Author(s) 2014. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.