SOME STUDIES ON PSEUDOMONAS AERUGINOSA ISOLATED FROM RABBITS IN ALEXANDRIA GOVERNORATE

Abeer H. Ali, *Shahenaz M. H. Hassan, Nahed F. Zaghlool, Sanaa A. El-Shamy and Sawsan Kh. M. Ebied

ABSTRACT

One hundred nasal swabs collected from diseased rabbits (1-4 months of age) were examined for isolation of Pseudomonas aeruginosa. It was isolated from rabbits suffering from respiratory manifestations (sneezing and nasal discharge). The isolates were identified based on growth pattern, colonial morphology, biochemical characteristics as well as molecular identification by conventional PCR using Pseudomonas aeruginosa specific primers and its carbapenemase genes (VIM, IMP, KPC) were investigated. The pathogenicity of isolates were investigated through experimental infection of susceptible rabbits, and the causative organism, P. aeruginosa was re-isolated from experimental animals in pure form. Some haematolological, biochemical and histopathological parameters were determined. The bacteriological examination revealed that 9 (9%) of the examined samples were positive for Ps. aeruginosa which proved to be pathogenic. Antibacterial susceptibility of the isolates were investigated. The results of antibiogram of the isolates showed that 6 isolates (6%) were resistant to all antimicrobials used except for Colistin they found to be susceptible. Examination of the six isolates showing resistance to Imipenem for carbapenemase genes (VIM, IMP and KPC) by PCR found to be all positive for the three examined genes. The clinical signs and post-mortem examination of experimentally infected rabbits were recorded. Also, morophological and biochemical examinations of the re-isolated Ps. aeruginosa were carried out. The hematological results showed significant decrease (P≤ 0.05) in total erythrocytic count, haemoglobin concentration, PCV, total leucocytic count, with significant increase in neutrophil lymphocyte count ratio (NLCR) of infected rabbits (3.3±0.7) compared to non-infected control (0.3±0.6).Serum AST, ALT, urea, creatinine and globulin were significantly increased in Ps. aeruginosa experimentally infected rabbits in comparison to non-infected control. Histopathological examinations revealed pulmonary congestion, edema and hemorrhages, focal interstitial pneumonia with mononuclear cell infiltration accumulated in alveolar lumena& alveolar septa; necrobiotic changes in liver and kidney with focal interstitial nephritis; and lymphoid hyperplasia in lymphoid tissue. Detection of multidrug resistant Ps. aeruginosa pose a health hazard for both rabbits and human.

Keywords: Rabbits, Ps. Aeruginosa, Antibiogram, Carbapenemases, Haematology, pathology.