Molecular Identification of Methicillin-Resistant and Methicillin Susceptible Staphylococcus aureus Using RAPD Indicators

Abstract

The present study aimed to investigate the relatedness and genomic variability between strains of methicillin resistant and of methicillin susceptible Staphylococcus aureus. Staphylococcus aureus, a gram-positive coccoid bacterium, is a common human pathogen that has the ability to cause a wide array of severe hospital and community-acquired infections, such as pneumonia, bacteremia, sepsis and toxic shock syndrome. The study included 100 local isolates of S. aureus collected from different clinical cases of nonrelated patients. All sample isolates were grown at 37°C on manitol salt agar medium and were been identified at the species level using morphological characteristics and biochemical tests. DNA profile of the samples obtained were detected by inspecting the banding pattern visually. Depending on the primers, the amount of bands and banding pattern varied. The presence or absence of a band at any place on the gel was scored to create a two-dimensional binary matrix. The application of RAPD technique was preceded by extraction of genomic DNA using the boiling method. mec A gene was amplified to distinguish MRSA strains without the need to perform antibiotic susceptibility. Our data had demonstrated ability of RAPD analysis to differentiate strains at intra-specific level also it can be applied successfully to assess the genetic backgrounds among isolates.