DETECTION AND SEQUENCING OF TN1546 TRANSPOSON IN TWO VANCOMYCIN-RESISTANT STAPHYLOCOCCUS AUREUS

Background and Aim:Tn1546 is a Tn3-related transposon conferring vancomycin resistance, consists of a cluster of seven genes including vanS, vanR, vanH, vanA, vanX, vanY, and vanZ.The aim of this study was detection and sequencing of Tn1546 transposon in two vancomycin-resistant Staphylococcus aureus.Methods:During 2015-2016, two vancomycin resistant S. aureus were isolated from two hospitalized patient in Kerman, Iran. The Tn1546 transposon was amplified and sequenced by primer walking method using primers designed by Primer designing tool in NCBI (https://www.ncbi.nlm.nih.gov/tools/primer-blast) for different regions of Tn1546. The sequences were assembled by Lasergene 6 software (DNASTAR) and analyzed by the basic local alignment search tool (BLAST) in NCBI (https://blast.ncbi.nlm.nih.gov/Blast.cgi). Open reading frames (ORF) were determined from contiguous sequences tag obtained using open reading frame finder software (https://www.ncbi.nlm.nih.gov/orffinder).Results:The amplification and sequencing of Tn1546 showed that, this transposon contain 9 genes, a transposase (tnp) and resolvase (rev) genes connected via ORF2 to vanR, vanS, vanH, vanA, vanX, vanY and vanZ, respectively. Analysis of the sequence of Tn1546 indicated closely related to Tn1546 in Enterococci spp. The sequence of Tn1546 was submitted in GenBank under accession number MG592387.Conclusion:By sequencing of Tn1546, we found its closed phylogenetic relationship with ancestral Enterococci spp. which can probably confirmed that the Tn1546 was transferred from Enterococci spp. to S. aureus in our hospital settings.

Keywords:

Vancomycin resistance , S. aureus , Tn1546