VetScan 2009 Vol 4 No 1 ISSN 0973-6980 29 www.vetscan.co.in 1 Kohat University of Science and Technology, Kohat 2 National Veterinary Laboratory, Park Road, Islamabad 3 Department of Microbiology, Quaid-e-Azam University, Islamabad Article 36 Differentation of closely related Vaccinal Strains of Pasteurella multocida using Polymerase Chain Reaction(PCR) Waheed ullah 1 , Muhammad Abubakar* 2 , Muhammad Javed Arshed 2 , Syed Muhammad Jamal 2 , Najma Ayub 3 and Qurban Ali 2 Nucleic acid based differentiation of closely related Pasteurella multocida vaccinal strains was performed. Morphological and biochemical characterization, HS-specific and species-specific PCR analysis of Pasteurella multocida vaccinal strains were demonstrated useful in distinguishing hemorrhagic septicemia-causing type B strains. The PCR assay performed for species specific P. multocida by using primer pair KMT1T7 and KMTISP6 resulted in amplification of all the strains. Another PCR analysis carried out for H.S. causing strain conformation by using primer pairs KTT72 and KTSP61 showed that only H.S. causing strains were amplified. It was also observed that PCR amplification performed directly on bacterial colonies or cultures was an extremely rapid, sensitive method of P. multocida identification. KEYWORDS Pasteurella multocida, Primers and PCR. INTRODUCTION Pasteurella multocida is a small, gram-negative, non–spore-forming cocco-bacillus with bipolar staining. It often exists as a commensal in the upper respiratory tract of many livestock, poultry, and domestic pet species and causes Haemorrhagic septicaemia (HS); a major disease of cattle and buffaloes occurring as catastrophic epizootics in many Asian and African countries, resulting in high mortality and morbidity. The disease has been recorded in wild mammals in several Asian and European countries. The Asian serotype B:2 and the African serotype E:2 (Carter and Heddleston system), corresponding to 6:B and 6:E (Namioka-carter system), are mainly responsible for the disease. In wild animals, serotype B:2,5 is predominantly present. The association of other serotypes, namely A:1, A:3 with a HS-like condition in cattle and buffaloes in India has been recorded (De-Alwis, 1990). Vaccination against P. multocida can be achieved with whole-cell bacterins. However, efficacy is limited and restricted to the homologous serotype. Plain-bacterin, alum-type precipitated bacterin, and oil-adjuvant bacterin constitute the three widely used types of HS vaccine among which oil-adjuvant bacterin is the most effective. A live intranasal vaccine prepared from a B:3,4 serotype of deer origin is also being used with reported success in southeast Asia (Muneer and Afzal, 1989). Since the disease been reported even in the vaccinated animals and vaccination failure reports are common therefore the present study was undertaken with the objectives of; morphological and biochemical characterization of P. multocida, HS-specific and species-specific PCR analysis of Pasteurella multocida vaccinal strains to obtain a clear picture of HS vaccinal strains.