PHENOTYPIC, GENOTYPIC AND PATHOGENICITY STUDIES OF PASTEURELLA MULTOCIDA ISOLATED FROM CHICKENS IN JOS OF PLATEAU STATE, NIGERIA
PHENOTYPIC, GENOTYPIC AND PATHOGENICITY STUDIES OF PASTEURELLA MULTOCIDA ISOLATED FROM CHICKENS IN JOS OF PLATEAU STATE, NIGERIA
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Date
2013-02
Authors
DASHE, Yakubu Gunya Dogonyaro.
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Abstract
ABSTRACT
Sporadic outbreaks of fowl cholera have been experienced from time to time in Jos, Nigeria
despite vaccination against the disease. This study was conducted from November, 2010 to
October, 2011 to determine the phenotypic and genotypic profile of Pasteurella multocida
isolated from chickens in Jos, Nigeria. A total of 400 oro-pharyngeal swabs from apparently
healthy chickens and 2,000 samples consisting of bone marrow, heart, liver, lungs and spleen
(400 each) were collected from 400 clinically sick chickens and analyzed bacteriologically
for Pasteurella multocida. Swab from each sample was cultured on 7% defibrinated sheep
blood, MacConkey and casein sucrose yeast agar. Presumptive colonies of Pasteurella
multocida were subjected to biochemical tests. Isolates identified by biochemical tests were
further subjected to Microbat 24E test and Pasteurella multocida specific Polymerase Chain
Reaction. Multiplex PCR typing using specific primers for capsular types CAP A, CAP B,
CAP D, CAP E and CAP F was carried out on all Pasteurella multocida isolates.
Biochemical tests identified Pasteurella multocida in 1.0% of clinically sick chickens. The
monthly frequency of isolation of P. multocida showed that the bacterium was isolated
mostly between the months of July and October. Pasteurella multocida was isolated from
5(1.3%) apparently healthy birds. Pasteurella multocida serotypes A: 1, A: 3 and A: 4 were
identified in Jos, Nigeria. Polymerase Chain Reaction recognized only 12 P. multocida
isolates out of 25 isolates, showing a specific amplicon of 460 base pairs. The amplification
of capsular genes in these 12 isolates by multiplex PCR showed band sizes of 1,044 base
pairs signifying that all the 12 P. multocida isolates belong to capsular group A. Disk
diffusion test was employed to assess the sensitivity of all P. multocida isolates confirmed by
PCR. Ciprofloxacin and gentamicin were highly effective (100%) against the twelve P.
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multocida isolates. High rates resistance by P. multocida isolates were recorded for
ampicillin and amoxicillin/clavulanate acid among others. The gross lesions in chickens
infected with P. multocida serotypes A1 and A3 were prominent keel, congested heart, liver,
kidneys and lungs. Histopathologically, moderate to severe lymphocytic, heterophilic and
macrophage cellular infiltration were noticed in the lungs and heart of chickens. In Japanese
quails, congested heart, liver and lungs were seen. Cellular infiltrations were noticed in the
lungs and heart of infected Japanese quails. Pathogenicity study indicated that P. multocida
serotypes A: 1, A: 3 and A: 4 caused (100%) mortality in mice. Moderate cellular
infiltrations were noticed in the lungs and heart of mice. In conclusion, it was observed that
P. multocida serotypes A: 1, A: 3 and A: 4 were identified in Jos metropolis and they caused
mortality in experimentally infected chickens, Japanese quails and mice. This indicates that
the antigenic component of the fowl cholera vaccine which is capsular group A and serotype
1 that is produced in the country may be limited in scope; it is therefore recommended that
the vaccine should be re-validated by incorporating the prevailing serotypes of P. multocida
in Nigeria such as serotypes A: 3 and A: 4 in order to widen the protection margin.
Description
DEPARTMENT OF MICROBIOLOGY
FACULTY OF VETERINARY MEDICINE, AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA.
Keywords
PHENOTYPIC,, GENOTYPIC,, PATHOGENICITY,, STUDIES,, PASTEURELLA,, MULTOCIDA,, ISOLATED,, CHICKENS,, JOS,, PLATEAU,, STATE,, NIGERIA.