Molecular typing of Salmonella enterica serovars Typhimurium and Enteritidis isolated from Taif area of Saudi Arabia by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR)

Twenty three isolates of Salmonella enterica representing two serovars, Salmonella Typhimurium and Salmonella Enteritidis isolated from three hospitals in Taif province, Kingdom of Saudi Arabia, were allocated to 23 genomic types using random amplified polymorphic DNA RAPD-PCR employing four 10-mer arbitrary primers. Jaccard's similarity coefficients were used to reveal the genetic diversity among isolates. Random amplified polymorphic DNA-polymerase chain reactioin (RAPD-PCR) amplified a total of 55 distinct bands (54 polymorphic bands or 98%). Cluster analysis based on the combined data from the four primers indicated that each of the S. Enteritidis or S. Typhimurium isolates had a distinct RAPD type. Principal component analysis (PCA) showed that the first three components explained about 65 and 33% of the total variability among RAPD types belonging to serovars Enteritidis and Typhimurium, respectively. The isolates belonging to serovar Enteritidis exhibited considerable genetic variation between locations, while those belonging to serovar Typhimurium exhibited considerable genetic variation both within and between locations. RAPD-PCR yielded highly reproducible results that demonstrated the high genetic heterogeneity of Salmonella isolates. Several genovars were present among Salmonella serovars and no specific RAPD type (or genovar) was found to be predominantly circulating in Taif province. The results presented here indicated that RAPD analysis has a great discriminatory power for the differentiation of Salmonella isolates and, therefore, can be a useful tool for the analysis of Salmonella genovars.