Phenotype and Genotypic Characteristics of Isolated Clinical Salmonella typhi Strains from Children with Diarrhea

Background: Salmonella and its stereotypes are an important source of human food contamination and are very strong and pathogenic in humans. Objectives: This study aimed to isolate Salmonella typhi from children with diarrhea and study its phenotypic and genotypic characterizations. Materials and Methods: In this study, 150 stool samples of children with diarrhea were collected from hospitals and medical centers and were transferred to the specialized laboratory of Islamic Azad University, Sabzevar branch, with full respect for health conditions. Peptone water, Selenite F broth, XLD, and Salmonella Shigella agar were used for primary isolation. To confirm the diagnosis, biochemical tests, such as triple sugar iron, urea agar, VogesProskauer, Indole, Simmons’ citrate, and movement, were used. Results: A total of 45 cases of Salmonella bacteria were isolated using the microbial culture method. This is while using the Multiplex polymerase chain reaction (PCR) molecular method, resistance and pathogenicity genes were detected in all 45 cases of Salmonella bacteria in the samples, and most of them are homogenous in terms of antibiotic resistance content, both phenotypically and molecularly were the target genes. Therefore, it can be said that the PCR method is more accurate than the microbial culture and also the traditional methods of microbial culture are often time-consuming, tiring, and expensive. Conclusion: This study concludes that for diagnosis and isolation of bacteria, two methods are generally used, such as traditional methods and new methods. However, the isolation of bacteria by these methods is time-consuming and time-effective and has always caused problems for researchers. This is especially important when faced with time limitations and we have to announce the result immediately or in cases where we encounter the size of the samples.