Molecular comparison of Staphylococcus aureus strains based on the Tn916 transposon and the Shine-Dalgarno sequences

Staphylococcus aureus is a major agent of hospital-acquired infections. It has become one of the most important health problems in the world due to its potential pathogenicity and growing resistance to antimicrobial medications. The present research confirmed the presence of the tet(M) gene and the Tn916 transposon after the detection of tetracycline-resistant strains of S. aureus . The genetic polymorphism of S. aureus strains was investigated by comparing the positions of Tn916 and Shine-Dalgarno sequence. A total of 30 pathogenic strains of S. aureus were used. The strain resistance was measured against five antibiotics, including tetracycline, by using antibiotic discs. The presence of the tet(M) gene and Tn916 transposon was studied in all strains by the PCR technique. Sequence sizes between these genetic elements were also tested with specific primers of the Tn916 transposon and Shine-Dalgarno sequences. The size of the produced bands was determined. Then, the presence and absence of the bands were converted to a 0-1 binary matrix, and the phylogenic tree of these strains was drawn and clustered in the Past3 software package. All studied strains of S. aureus were resistant to tetracycline and had the tet(M) gene and the Tn916 transposon. The investigation of the distances between Tn916 and Shine-Dalgarno sequences revealed different band patterns among these strains. The phylogenetic clustering based on the PCR band pattern classified the strains that were entirely similar in terms of all antibiogram tests, tet(M) , and Tn916 transposon presence into seven separate clusters, reflecting the genetic diversity and polymorphism of these strains. Our findings can be useful in the search for effective treatments against S. aureus .