KICH, J. D.

KLEIN, C. S.

MORES, M. A. Z.

MORES, N.

OLIVEIRA FILHO, J. X. de

REBELATTO, R.

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Proceedings of the23rd International Pig Veterinary Society(IPVS) CongressJune 8 – 11, 2014 Cancun, Quintana Roo, MexicoMEXICO2014CONGRESS23rdVOLUME II!Proceedings of the 23rd International Pig Veterinary Society  (IPVS) Congress  Volume 2  Poster presentations             June 8 – 11, 2014 Cancun, Quintana Roo, Mexico  Poster                                                        Pasteurella multocida 360!Proceedings of the 23rd IPVS Congress, Cancun, Mexico – June 8-11, 2014 P.371  Study of the molecular profile in strains of Pasteurella multocida serotype A from lung lesions in swine  CS Klein1, R Rebelatto1, JX de Oliveira Filho2, MAZ Morés1, JD Kich1, N Morés1 1Embrapa Swine and Poultry, Brazil; 2Department of Animal Medicine at UFRGS, Brazil. catia.klein@embrapa.br!  Introduction !Pasteurella multocida A (P. multocida) is a common bacteria isolated from swine respiratory tract. Despite of been considered an opportunistic [5], this pathogen has been associated with lung lesions, pleurisy and pericarditis observed in field outbreaks and experimental challenges [3]. The objective of this study was to evaluate the molecular profile of different strains of P. multocida from eight Brazilian States. Studies included information on species-specific genes, capsular typing and virulence genes.   Materials and Methods A total of 157 P. multocida strains, previously characterized, by standard biochemical procedures, like P. multocida serotype A were analyzed. The strains were recovered from pneumonic lungs of pigs from farms and slaughterhouses in the eight major pork producer states in Brazil. DNA samples were analysed by multiplex PCR to detect capsular genes type A, D, F and the species-specific kmt1 gene [6]. Virulence genes were detected by PCR specific for toxA (dermonecrotic toxin), tbpA (binding protein hemoglobin), hgbB (mechanisms of iron acquisition) and pfhA (filamentous hemagglutinin-bacterial adhesion factor) [1]. One amplified fragment from each gene was sequenced, and the specificity was confirmed by the GenBank database using the BLAST tool.  Results All studied 157 strains were positive for the P. multocida species-specific gene kmt1. In addition, 94.9% (149/157) were positive for capsule type A and 5.1% (8/157) for the capsule type D. None strains were identified as type F. Investigation of virulence factors, showed no positive results for toxA and tbpA genes. However, 31.8% (50/157) and 82.8% (130/157) of the strains harbored the pfhA and hgbB genes, respectively. Only 14% (10/157) of the samples harbored both pfhA and hgbB genes, therefore, 85.4% (134/157) of strains were positive to a single one of these genes. P. multocida positive for pfhA and hgbB genes, important virulence factors, were identified in all investigated Brazilian states. ! Conclusions and Discussion!All strains of this study were verified as P. multocida and the capsular serotype A was widely predominant. The high prevalence of hemoglobin binding protein coding by hgbB gene suggests that an additional advantage to increase the pathogenicity [7].The hgbB gene was detected in the majority of studied strains, even though P. multocida does not show visible and classical hemolysis [7]. Possibly, this gene’s presence is related to occurrence of lesions. The genetic arrangement of tbpA support a possible transpositional recombination event of this genetic locus from non or low pathogenic to highly virulent P. multocida strains [2]. Both the toxA gene coding the dermonecrotic toxin and the tbpA gene, which was previously described factor involved in hemorrhagic septicemia in cattle [2] were not detected. The toxA, tbpA and pfhA as well as the capsule biosynthesis genes are important marker genes to define the pathogenic potential of P. multocida strains [2]. The pfhA gene codes a protein associated to a bacterial adhesion factor in respiratory tract. This gene was present in 31.8% of strains, in agreement with Ewers [2]. Experimental studies in pigs using different virulence genes profiles are needed to understand their effect in the pathogenicity. In conclusion, the P. multocida A was the most prevalent serotype and it is widely distributed in pneumonic lesions in pigs from farms and slaughterhouses in Brazil. In addition, P. multocida A strains harbor different virulence related genes.  References 1. Atashpaz, S. et al. Res. Vet. Sci., v.87, p. 355-7, 2009.  2. Ewers, C. et al. Vet. Microbiol., v. 114, 304–317. 2006.  3. Kich, J.D. et al. Com. Téc.. 469, Embrapa Suínos e Aves: 2007, 7p.  4. Register, K.B. et al. Diseases of Swine. 10 ed. Ames-USA: 2012. P. 798-810.  5. Towsend, K.M. et al. J. Clin. Microb., v.39, p.924-9. 2001.  6. Subhash, V. et al. Vet. Res. Commun, 2012. DOI 10.1007/S 11259-012-95395.  

Study of the molecular profile in strains of Pasteurella multocida serotype A from lung lesions in swine.

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