Detection and Pathogenicity of Pasteurella Multocida Isolated From Layer Farms in Egypt

Abstract

In this study 300 samples were taken from different layer farms in Egypt (El-Sharqia, Elmina, Assiut and Sohag) showing remarkable signs for fowl cholera and examined for detection of P. multocida. Isolation of P. multocida was from liver, lung and trachea. The targeted bacteria were isolated, identified and molecularly characterized. P. multocida were recovered from 8 cases (2.6%) and confirmed using phenotypic characterization. By multiplex PCR assay which considered a rapid diagnostic method for fowl Cholera confirmatory recognition regardless to serotypes, isolates were P. multocida serotype (A) at expected size; 1044 bp. Antimicrobial susceptibility test used to determine the minimal inhibitory concentration to all isolates resulted in high susceptibility to amoxicillin and doxycycline and with variable pattern of sensitivity to the other antibiotic. Studying pathogenicity of P.multocida capsular type A was carried out in Ross broiler chickens aged 21 days old through oropharyngeal inoculation (0.5 ml) brain heart infusion broth containing 2.93x10 8 CFU. Characteristic mild respiratory signs were observed within 48 h and persisted for 9 day with 8% mortality. Mild septicemic lesions comprising of white necrotic foci and pinpoint hemorrhages in the coronary fat of the heart, liver and sever inflammation in pancreas were observed. This study has documented the incidence of fowl cholera in broiler chickens to some extent mild to moderate degree of the disease.