Genetic characterization of two vancomycin-resistant Staphylococcus aureus isolates in Kerman, Iran
Received 16 February 2019
Accepted for publication 29 May 2019
Published 4 July 2019 Volume 2019:12 Pages 1869—1875
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Cristina Weinberg
Peer reviewer comments 2
Editor who approved publication: Dr Sahil Khanna
Mahsa Ziasistani1,2, Mohammad Reza Shakibaie3,4, Davood Kalantar-Neyestanaki3
1Student Research Committee, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran; 2Pathology and Stem Cell Research Center٫ Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran; 3Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran; 4Research Center for Infectious Diseases and Tropical Medicine, Kerman University of Medical Sciences, Kerman, Iran
Aim: The aim of this study was the genetic characterization of two clinical vancomycin-resistant Staphylococcus aureus (VRSA) isolates.
Materials and methods: Resistance to vancomycin was determined by phenotypic method. PCR was used for detection of mecA, vanA, ermA, ermB, ermC, msrA/B, aph(2”)-Ic, aph(3ʹ)-IIIa, pvl, Immune Evasion Cluster [sea, sep, chip, sak and scn] genes and biofilm operon icaABCD. On the other hand, multilocus sequence typing and agr typing methods were performed for the determination of clonal relationship and van operon was detected and sequenced.
Results: Vancomycin-resistant Staphylococcus aureus strain 1 (VRSA-1) was positive for vanA, ermA, ermC, aph(2”)-Ic, aph(3ʹ)-IIIa, sea, sep, icaD genes, belonging to agr type I; SCCmec type III; spa type t030; and ST239. However, the genetic characterization of Vancomycin-resistant Staphylococcus aureus strain 2 (VRSA-2) revealed the presence of various types of resistance genes vanA, ermA, ermC, aph(2”)-Ic, aph(3ʹ)-IIIa, sea, icaD, relating to agr type I; SCCmec type III; spa type t459; and ST239. The presence of transposon Tn1546 was determined by PCR sequencing.The Basic Local Alignment Search Tool analysis of van operon in the VRSA isolates showed 99.6% sequence homology to Tn1546 in vancomycin-resistant enterococci, indicating the vanA operon has an enterococcal origin.
Conclusion: In conclusion, the ST239 is one of the most common clones of MRSA isolates which involved the hospital-associated infections, therefore, the emergence of VRSA isolates with ST239 increased the spread of resistance to vancomycin in the hospital settings.
Keywords: VRSA, MLST, SCCmec, spa, agr type, van operon
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