Respiratory diseases affected broiler chickens is a problem threat their production and cause a great loses among them. This study was conducted to determine the prevalence and identification of Klebsiella pneumoniae isolates from varying age clinically diseased broiler chickens in Gharbia governorate. A total of 400 internal organs (heart, lung, liver and spleen)
collected from 100 diseased chickens suffered from respiratory manifestation were subjected to detect rate of Klebsiella pneumoniae prevalence and detection of isolates susceptibility patterns to various antibiotics by disc diffusion method. In addition, these isolates were screened for the presence of selected virulence genes including, rmpA (regulator of the
mucoid phenotype A), magA (mucoviscosity associated gene), wcaG and antibiotic resistance genes (blaTEM and blaSHV) by using PCR. Bacteriological examination revealed that isolation of Klebsiella Pneumonia with a total prevalence rate reached (13%) as 13 out of 100 examined cases where (27) isolates of K. pneumoniae were detected. The highest percentage of isolation of K. pneumoniae was from lung (13%) followed by liver (7%) then spleen 5% and finally from heart (2%). All of the isolates were resistance to Ampicillin. The rate of resistance to other antibiotics was as follows, 25 (92.6%) to
Lincomycin, 24 (88.9%) to Oxytetracycline, 22 (81.5%) to cefotaxime a n d Doxycycline. 9 (33.3%)to ciprofloxacin, 8 (29.6%) toAmoxicillin / clavulanic acid, 7 (25.9%) to Norfloxacin, 6 (22.2%) to gentamicin, and all of the isolates were sensitive to amikacin. Klebsiella Pneumonia isolates were confirmed by PCR for detection of gyrA and 16S-23S ITS genes, all isolates were positive for antibiotic resistance genes (blaTEM and blaSHV) and negative for magA, rmpA and wcaG genes.