The current study was aimed to investigate the incidence of different Salmonella serovars in chicken products either from local or imported source. A total of 152 samples of chicken and chicken products were collected from different retail establishment markets in Riyadh, KSA including 38 local whole frozen chickens, 62 imported whole frozen chickens, 22 whole poultry eggs and 30 local chicken cuts samples and examined by standard microbiological techniques (SMT). Salmonella isolation revealed a total percentage of 5.92%; chicken cuts revealed a high incidence among the examined samples (10%), followed by local frozen chickens and imported frozen chicken samples with incidence of 7.89 and 4.83%, respectively. For this experiment, the whole chicken eggs were negative for Salmonella species by SMT. Salmonella enteritidis was dominating among the recovered Salmonella serovars, followed by Salmonella typhimurium, while only two strains of Salmonella agona and Salmonella newport were isolated. The PCR assay combined with Rappaport-Vassiliadis (RV) selective broth (PCR-RV) for the detection of Salmonella species in the collected field samples revealed the same positive samples directly from the imported frozen chickens and whole chicken eggs which gave negative results by SMT. Thus PCR-RV technique is rapid, time saving and applicable to detect Salmonella serovars directly from chicken samples.

In this study, pulsed field gel electrophoresis (PFGE) was used for genomic DNA finger printings of methicillin-resistant Staphylococcus aureus (MRSA) isolates. Thirty strains of S. aureus collected from major hospital laboratories and public health centers, Riyadh, King Saudi Arabia were tested phenotypically by conventional methods and genotypically by multiplex-PCR for direct detection of S. aureus 16S rRNA and mecA genes. The chromosomal DNA of the isolates was examined by using pulsed-field gel electrophoresis (PFGE) using SmaI. SmaI cut the chromosomal DNA of the examined MRSA into 9 to 13 fragments, moreover, 16 chromosomal digestion patterns were observed out of the 30 examined isolates. The first pulsed field gel electrophoresis (PFGE1) contains 9 strains recovered from soft tissue infections and surgical wound infections. The second one (PFGE 2) contains 4 MRSA isolates, 3 of which were recovered from skin and soft tissue infections, while one was recovered from wound infection. Moreover, there are 3 chromosomal digestion patterns (PFGE 3, 4 and 5), each pattern involved two strains of MRSA which were recovered from surgical wound infections. A dendrogram of percent similarity, revealed three major clusters, the first cluster containing four groups (17 strains). The second cluster contains one group (12 strains), while the third cluster contains only one strain recovered from deep abscess.