Molecular epidemiology and genetic background of PVLpositiveS. aureus clinical strains isolated from Iranian patients using acombination of multilocus sequence typing (MLST) analysis

Background and Aim : Staphylococcus aureus (S. aureus)-associated disorders vary from skininfections to life-threatening invasive diseases, such as bacteremia, sepsis, and endocarditis,mediated by a variety of virulence factor. Panton-Valentine Leukocidin (PVL) is a two-componenttoxin produced by some S. aureus strains in varying amounts. The population structure and clonesof PVL-positive S. aureus strains are changing in different healthcare facilities in differentcountries. The present study aimed to obtain a more complete description about the molecularepidemiology and genetic background of PVL-positive S. aureus clinical strains isolated fromIranian patients using a combination of multilocus sequence typing (MLST) analysisMethods : A total of ۲۸ PVL-positive S. aureus strains were detected from ۶۰۰ S. aureus isolatesbetween February ۲۰۱۶ and March ۲۰۱۹ from different hospitals in Tehran, Iran. MLST wasperformed for all S. aureus strains using previously reported primers specific for sevenhousekeeping genes, including arcC, aroE, glpF, gmk, pta, tpi, and yqiL, according to thepreviously described protocol. The sequences of the PCR products were compared to those of theexisting alleles available on the MLST website (https://pubmlst.org/saureus/) and analyzed onlineto assign allelic profile (sequence type, ST) and the associated clonal complex (CC).Results : The isolates encompassed ۲۱ different sequence types (STs), of which ۱۶ STs did nothave matching profiles in the MLST database and were subsequently designated to ST۵۱۴۷-ST۵۱۶۲ after submitting the data to the website (https://pubmlst.org/saureus/).Other STs identifiedwas, ST۳۰ (۶/۲۸, ۲۱.۴%), ST۱۹۹۶ and ST۱۱۳۶, (۲/۲۸, ۷.۱%), ST۱۲۱ and ST۲۲(۱/۲۸,۳.۵۷%).Based on eBURST analysis, the isolates were clustered into five CCs, including CC۳۰,CC۲۲, CC۱, CC۸, and CC۵ and nine singleton.Conclusion : Although different clones were identified in this study, CC۳۰ (۳۱.۶%) and CC۲۲(۲۱%) were identified as the dominant clones among PVL-encoding S. aureus strains. Also, bothCC۲۲ and CC۳۰ clones have been reported to be predominant in Asian countries. Thepredominance of CC۲۲ and CC۳۰ clones among PVL-positive strains in Iran is of great concern,as these clones appear to be highly transmissible with a propensity to spread worldwide. This studypromotes a better understanding of the molecular epidemiology and evolution of PVL-positive S.aureus strains in Iran.

کلیدواژه ها:

Staphylococcus aureus ، PVL ، MLST