الفهرس 
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Abstract
Ninety nine samples were collected from different poultry farms in which chickens showed lesions of proventriculitis. These samples were investigated in order to obtain a view about the bacterial species associate proventriculitis, their behavior against various antibiotics. Additionally, investigation of the prevalence of virulence genes (lasI,phzMandtoxA) of P. aeruginosa recovered from proventriculitis. Moreover, sequence analysis and determination to the correlation of toxA and lasI genes of P. aeruginosa comparable to those recovered from different origins in Egypt (when available) and worldwide.
Bacteriological examination of broiler proventricular samples revealed that 75 specimens of proventriculitis were positive to bacterial isolation with a prevalence of 75.8%. The prevalence of the recovered bacterial species in descending order were P. aeruginosa 39.4%, C. perfringens 18.2% and different bacterial species from family Enterobacteriaceae including P. mirabilis, Citrobacterspp., E. coli, E. aerogenes and K. pneumoniae in prevalence of 26.3, 8.1, 6.1, 1 and 1% respectively.
Serological identification of E. coli isolates obtained from proventriculitis revealed six isolates of E. coli O158 and two isolates of E. coli O146 with prevalence of 75 and 25% in order.
Concerning to E. coli recovered from proventriculitis, they showed complete resistance to ampicillin and cefazolin. But what is worse; gentamicin, ceftriaxone, chloramphenicol, and ciprofloxacin showed 87.5, 62.5, 62.5, 62.5 and 0, 0, 25, 25 % non-susceptible patterns (i.e. resistant and intermediate) respectively with the investigated isolates. Additionally, they showed 100% MDR pattern against at least one member of three antimicrobial classes and extended to eight out of the tested antimicrobial classes within 2 (25%) of the isolates under test.
The results of in vitro sensitivity test of P. aeruginosa isolated from proventriculitis against different chemotherapeutic agents revealed that the most effective antibiotic was ceftazidime (93.6%) while all of tested isolates resisted completely ampicillin, cefazolin, chloramphenicol and tigecycline. Moreover, the investigated P. aeruginosa isolates showed variable degrees of resistance against cefoxitin, ertapenem and ceftriaxone with 97.9, 76.6 and 74.5% respectively. All P. aeruginosa under test showed MDR pattern; they resisted at least a single agent in four and extended to 11 of the tested antimicrobial classes within 6 (12.8%) of the isolates under test.
Double disk diffusion test was used to detect ESBLs phenotypically. ESBLs was detected in 3/8 (37.5%) out of the studied E. coli and 6/47 (12.8%) out of the investigated P. aeruginosa isolates utilizing aztreonam, cefepime, cefotaxime and ceftazidime antibiotics around amoxicillin-clavulanic acid disk.
Antimicrobial disk diffusion test ofE. coli, only one isolate (12.5%) resisted cefoxitin and confirmed to contain AmpC using cefoxitin-cloxacillin combined disk test.Regarding P. aeruginosa showed 46 out of 47 recovered from proventriculitis to be resistant to cefoxitin and by cefoxitin-cloxacillin combined disk confirmed the presence of AmpC within the investigated isolates.
P. aeruginosa represents common bacterial isolate of highly concern and economic impact in avian industry. PCR was performed in a trial to investigate virulence genes of P. aeruginosa in broiler chickens revealing its pathogenicity and compare the presence of these genes in P. aeruginosa recovered from clinical specimens in broiler chickens showing proventriculitis with those found on the gene bank. The results showed presence of virulence genes (lasI,phzM and toxA genes) with 100% of the investigated P. aeruginosa.
Nucleotide and amino acid sequence analysis of virulence genes (toxA and lasI genes) revealed the correlation between P. aeruginosa recovered from cases of proventriculitis in the present study with other sequences cited on gene bank. Sequencing revealed high correlation most of the time within the isolated P. aeruginosa and worldwide, especially with the reference strain of P. aeruginosa PAO1.