الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 168 |  |  |
| | | from | 168 | | |
Abstract
Abstract
Salmonella enterica is one of the leading causes of serious illness ranging from gastroenteritis to systemic infections including typhoid. Excessive use of antibiotics promotes the development of resistant Salmonella species.
Due to the occurrence of multidrug-resistant strains, alternative intervention strategies against Salmonella infections are urgently needed. One of the promising alternative control approaches is the possible beneficial use of probiotics against various pathogens, including Salmonella spp. Therefore, the aim of the present study was to validate the efficiency of probiotics on multidrug resistant Salmonella. So, seventy samples were collected from meat products (minced meat, burger, sausage, luncheon, kofta, raw meat, and canned beef) from different supermarkets in Benha City, Qalyubiyah Governorate. Microbiological examination of meat samples revealed that eight Salmonella isolates were obtained from all examined samples, the serotyping results showed that S. Typhimurium was the most prevalent serotype among Salmonella isolates. All Salmonella isolates were susceptible to meropenem and ciprofloxacin which could be used as drugs of choice for treatment. Meanwhile, 100% of Salmonella isolates were resistant to amoxicillin-clavulanic acid. The antimicrobial activity of probiotics (CFSM) in De Man, Rogosa and Sharpe (MRS) broth media by agar well diffusion method demonstrated that L. helveticus EMCC 1654 has highest activity against S. Anatum and S. Enteritidis, in case of CFSM in skim milk, L. Plantarum EMCC1027, L. helveticus EMCC 1654, Bactozyme and Lacteolfort showed antimicrobial activity, so it is clear that CFSM in MRS are more active than CFSM in skim milk. Antibiofilm potential mediated by CFSM of probiotics in MRS revealed that L. helveticus EMCC 1654 have the highest antibiofilm activity on the three tested Salmonella isolates. Phenotypically and genotypically L. helveticus EMCC 1654 significantly downregulated the expression of the two biofilm - related genes (sdiA& sipA) (2–9.8% of the untreated control). Similarly, CFSM of L. plantarum CCUG 30503 showed the same trend in downregulation of the two virulence genes (5.5–9.5% of the untreated control).