Study of genetic variation in Staphylococcus aureus strains isolated from clinical specimens by RAPD-PCR Technique

Methicillin Resistant-Staphylococcus aureus (MRSA) has been introduced as important factor in Hospital-Acquired Infections (HAI). Diversity in Staphylococcus strains can affect the response to treatment and identifying of strains can be effective in the selection of antibiotics. The aim of this study was to determine the genetic diversity of MRSA isolates with random primers.

This cross-sectional descriptive study was performed in 2015 on 50 MRSA isolates of clinical skin samples. Genomes were extracted by Boiling method. RAPD-PCR method was performed by 16 random primers. To investigate the genetic similarity, matrix 1/0, NTSYS and MVSP software's were used. One-dimensional clustering and ordinations were conducted.

The highest and lowest produced bonds related to M4 and M9 primers respectively. The greatest mean produced bands for each isolate/primer up to 8.1 relates to M4 primer. The most polymorphic bands, 36 bands belonged to M5 primer. The heaviest band, 3.6 Kb produced by M2 primer and the lightest band, 100 bp produced by M12 primer. A total of 16 primers, 583 bands formed that were 412 (70.91%) polymorphic bands and 171 (29.09%) specific bands. RAPD-PCR divided isolates into two clusters.

This study showed that these isolates are very heterogeneous genetically. RAPD-PCR is important in rapid detection of an epidemic outbreak, tracing the origin of the infection and the subsequent managing of infection control. Therefore, the present study tries to develop this approach and apply it in health management by providing information about the genetic diversity of MRSA.