Table of Contents
ISRN Microbiology
Volume 2012, Article ID 215275, 6 pages
Research Article

Genetic Characterization of Methicillin Resistant and Sensitive, Vancomycin Intermediate Staphylococcus aureus Strains Isolated from Different Iranian Hospitals

1Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, P.O. Box 73461-8174, Isfahan, Iran
2Department of Medical Biotechnology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran
3Department of Molecular Biology and Genetic Engineering, Stem Cell Technology Research Center, Tehran, Iran
4Department of Microbiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
5Food and Drug Laboratory Research Center, Ministry of Health and Medical Education, No. 408, Emam Khomeini Avenue, Tehran, Iran
6Reference Health Laboratories, Ministry of Health and Medical Education, Tehran, Iran
7Department of Epidemiology, School of Medicine, Isfahan University of Medical Sciences, P.O. Box 73461-8174, Isfahan, Iran

Received 5 November 2012; Accepted 22 November 2012

Academic Editors: C. K. Cote, P. Di Martino, S. H. Flint, and G. Koraimann

Copyright © 2012 Seyed Asghar Havaei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Global concerns have been raised due to upward trend of Vancomycin Intermediate Staphylococcus aureus (VISA) and Vancomycin Resistant Staphylococcus aureus (VRSA) reports which mean casting doubt on the absolute effectiveness of the last line of antibiotic treatment for S. aureus, vancomycin. Hence, epidemiological evaluation can improve global health care policies. Methodology. 171 Isolates of Staphylococcus aureus were collected from different types of clinical samples in selected hospitals in Isfahan, Mashhad, and Tehran, Iran. Then, they were evaluated by agar screening, disk diffusion, and MIC method to determine their resistance to vancomycin and methicillin. The isolated VISA strains were then confirmed with genetic analysis by the evaluation of mecA and vanA genes, SCCmec, agr, and spa type, and also toxin profiles. MLST was also performed. Results and Conclusion. Our data indicated that 67% of isolated S. aureus strains were resistant to methicillin. Furthermore, five isolates (2.9%) had intermediate resistance to vancomycin (VISA). In contrast to usual association of VISA with MRSA strains, we found two isolates of MSSA-VISA. Therefore, our data suggests a probable parallel growing trend of VISA towards MSSA, along with MRSA strains. However, more samples are required to confirm these primarily data. Moreover, genetic analysis of the isolated VISA strains revealed that these strains are endemic Asian clones.