الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 221 |  |  |
| | | from | 221 | | |
Abstract
Salmonellosis is the most important foodborne disease, in both animals and man .In the present study a total of 1500 Salmonella isolates were collected from chicken origin to detect ST. Twenty four ST isolates from chicken origin, one from duck, and one from infant diarrhea as well as standard ST strain (ATCC 14028) were investigated. All ST isolates were confirmed to be salmonellae biochemically by API 20E and serologically using poly and mono valent antisera. PCR was applied among the collected ST strains using primers specific for STM4497 gene of ST. In the present study, RAPD analysis was used to establish serotype-specific markers for Salmonella serotypes, with emphasis on Salmonella Typhimurium, due to its impor¬tance in causing diarrhea. Three different randomly designed primers (23 L, P1245 & 9mer) were used in PCR in the presence of ST DNA. The SDS profile analysis of the extracted OMPs of the examined ST isolates showing clearly that all isolates had 4 bands ranging in size 42-14 kDa. Protein bands of 38 and 15 kDa appeared as major bands in 65% and 55% of the isolates, respectively. Similarly most of ST isolates had bands at 39, 37 and 36 (50% each). It is clear that ST human, duck and chicken isolates showed similarity in the OMP profile analysis. Antimicrobial susceptibility test was assayed by the disc diffusion method on mueller Hinton agar. Salmonella Typhimurium strains were tested for sensitivities to 18 antibacterial agents. It is clear that most of the isolates were sensitive to ceftazidime, ciprofloxacin, colistin sulphate and norfloxacin (96.2% each) followed by gentamicin (92.3%), doxycycline, flumiquine and neomycin (88.5% each) then chloramphenicol and trimethoprime (84.6% each). While 100% of the isolates were resistant to erythromycin. In the present study the 27 ST isolates including ATCC14028 were examined for β- lactamase production found that 44.4% (12/27) ST isolates were positive for TEM gene. In addition 37% (10/27) and 59.3% (16/27) of ST strains were positive for CTX-M & SHV genes respectively. Also by using PCR 22.2% (6/27) ST isolates were positive for amplification of aadA1 gene. Sequencing of aadA1 streptomycin resistance gene among 6 ST isolates showing variable identity percent with randomly selected strains from gene bank.