Indian Journal of Comparative Microbiology, Immunology and Infectious Diseases

  • Year: 2011
  • Volume: 32
  • Issue: 1and2

Multilocus sequence typing of Indian isolates of Pasteurella multocida

  • Author:
  • R.A. Mir, P. Thomas, K.N. Viswas, S.K. Gupta, J.K. Verma, A.P. Singh1, V.P. Singh
  • Total Page Count: 6
  • DOI:
  • Page Number: 30 to 35

Division of Bacteriology & Mycology, Indian Veterinary Research Institute, Izatnagar - 243 122 (U.P.)

1Division of Microbiology, Pt. Deen Dayal Upadhyaya Pashu Chikitsha Vigyan Vishwa Vidyalaya Evam Go Anusandhan Sansthan, Mathura-281001, UP

Abstract

Haemorrhagic Septicemia (HS) which is caused by Pasteurella multocida accounts for heavy mortality in cattle and buffalo resulting in huge economic losses to the livestock industry. In the traditional method for typing Pasteurella multocida isolates by capsular and somatic typing the discrimination power of serotyping is very low and for the somatic serovars, there is no correlation between serovar distribution and overall population structure. The present study was envisaged (i) to characterize the Indian isolates of P. multocida of buffalo origin by using multi-locus sequence typing (MLST) system and (ii) to determine whether single or multiple strains of P. multocida tend to exist within India. The study was carried out on a total of 14 isolates obtained from across the country. PCR amplification of seven housekeeping genes was carried out and gene sequences were analyzed. The allelic profiles assigned to the fourteen isolates at the seven loci were 23, 37, 21, 17, 4, 2 and 17 for adk, est, pmi, zwf, mdh, gdh and pgi genes, respectively. All the fourteen isolates were grouped in one sequence type (ST122) and were submitted to the RIRDC MLST data base for P. multocida. Sequence types were analyzed by eBURST v3, START 2 software, UPMGA Tree analysis and Splits Tree analysis. eBURST analysis of all the fourteen isolates classified them into group number 23 when group definition was 5 or more matches. But when group definition was 6 or more matches all the fourteen isolates were grouped in group number 21 which in addition to ST122 has ST63. When analysis of the allelic profiles of all the fourteen isolates was carried out by using START 2 software it was found that both observed (V) and expected (V) variance were same. So it can be inferred that the bacterial pathogen under study is clonal with respect to haemorrhagic septicaemia causing serotypes isolated from buffaloes. Also, Splits Tree analysis corroborated this finding, showing a tree like rather than a network structure.