LPS-PCR typing of ovine Pasteurella multocida isolates from Iran based on (L1 to L8) outer core biosynthesis loci.

Abstract

Pasteurella multocida isa gram-negative bacterial pathogen that is causative agent of a wide range of diseases in many animal species and humans. Lipopolysaccharides (LPS) are an important virulence factor, minor changes to structure of which can exert dramatic effects on pathogenicity of P. multocida in its host. LPS can be used for the identification and classification of strains with somatic typing systems.The aim of this study was to identify the LPS genotypes of the ovine P. multocida isolates obtained from pneumonia cases in Iran. The LPS genotype of the isolates was determined using eight specific primers for LPS outer core biosynthesis loci. The LPS genes were amplified by polymerase chain reaction (PCR), then they were sequenced and compared to the sequences registered in the GenBank. Of the 32 ovine P. multocida isolates tested, 21 (65.62%) isolates belonged to genotype L6, 9 (28.12%) isolates contained genotype L3, 1 (3.12%) isolate had both L3 and L6 loci, and 1 (3.12%) isolate remained untypeable. The LPS-PCR was able to type 31 of 32 field ovine isolates from Iran. According to the phylogenetic analysis, L3 genotype isolates were grouped into two distinct lineages. LPS gene sequences among L6 genotypes of ovine P. multocida isolates from Iran and the related sequences in the GenBank were highly similar (>99.5%). LPS-PCR is an accurate genotyping method that was able to classify P. multocida strains into one of the eight distinct LPS genotypes.