Concurrent Molecular Study and Expression Analysis of Streptococcus pyogenes Superantigens under the Effect of Bacteriocin Nisin by Real-Time PCR Method

Aim: Group A Streptococcus (GAS) is the causative agent of several invasive and non-invasive diseases. Several virulence factors contribute to the pathogenesis of GAS, such as M protein, hemolysins, and extracellular enzymes. Due to the improper use of antibiotics, the resistance of these microorganisms to antibiotics is increasing. Bacteriocins as an alternative to antibiotics are of great importance. In this study, the effect of antimicrobial Bacteriocin nisin was investigated on the expression of smeZ gene.Materials & Methods: Samples were taken from the site of infection on the skin surface of the patients at the dermatology clinics of Tehran public hospitals. The specimen was immediately transferred to the primary culture medium or basal medium. Chromosomal DNA extraction was performed using the standard method for the extraction of Streptococcus pyogenes genomes. Multiplex PCR was performed to identify the presence of smeZ, speI, and speH genes in the isolates. The expression of smeZ gene was evaluated using the real-time PCR technique.Findings: The frequencies of smeZ, speI, and speH genes in ۱۲ S. pyogenes isolates were ۲۵, ۸.۳, and ۸.۳%, respectively. The fold change rate for smeZ gene was -۱.۲۰۹, indicating that this gene was decreased ۱.۲۰۹ folds in the treated group compared to the untreated group.Conclusion: Bacteriocin not only reduces the number of pathogens but may also affect the metabolism of the bacteria by producing toxins. The use of new antimicrobial agents in place of previous drugs for psoriasis patients could be considered as a way to treat the disease more effectively in the future.

Keywords:

Streptococcus pyogenes , Superantigens , Bacteriocin , Nisin , Real-time PCR