Role of Molecular Techniques in Characterization of Bacteria Causing Pneumonia in Small Ruminants

Sheep and goats are important agricultural animals in many developing countries which can compensate the shortage in cattle and buffaloes meat production besides wool and fiber. The most important reason of the sheep and goats losses is pneumonia in a percentage of 24-51% which causes economic losses from fatal pulmonary infections and impairment animal performance. Pneumonia could be occurred due to many fastidious bacterial pathogens, therefore the conventional methods for isolation and identification of these bacteria are useless. Nucleic acid-based assays have been established as gold standard for precise molecular identification and phylogenetic relationship within the family as well as on subspecies level. For instance; the 16S rDNA gene sequencing has been revealed that many isolates previously classified as ''Mannheimia haemolytica'' were Mannheimia glucosidal or Mannheimia ruminalis. Genomic subtraction studies identify a unique chromosomal region has successfully been used to detect Pasteurella multocida from suspected samples. Phylogenetic relationships of representative sheep and goat P. multocida serotype B: 2 isolates revealed two polymorphic sites were present in goat isolate vs one in sheep isolate. Polymerase chain reactions (PCRs) can be reliably used on mycoplasmas growing in culture even in the presence of bacterial contamination. The restriction enzyme analysis of rpoB gene may be useful to differentiate ovine strains from bovine strains of Histophilus somni, 16S rDNA gene amplification of Helcococcus ovis strain isolated from goat revealed that the nucleotide sequence matched 96%identity with that isolated from sheep. The molecular characterization can be used for early detection and precise discrimination of fastidious pathogens phylogeny as well as virulence genes as a future step for vaccine preparation. (A.S. Hakim, M. A. Bakry, Nagwa, S. S. Ata and Mona S. Zaki. Role of Molecular Techniques in Characterization of Bacteria Causing Pneumonia in Small Ruminants. Life Sci J 2014;11(6):147-153). (ISSN:1097-8135). http://www.lifesciencesite.com . 21