Coagulase-Negative Staphylococci Essay

In recent years, coagulase-negative staphylococci ,particularly the staphylococcus epidermidis , have been increasingly involved in nosocomial infections. Therefore, the identification of and distinguishing the bacteria from other coagulase-negative staphylococci is very important. Phenotypic methods used for their identification are time consuming and not precise. In this study, we used two molecular methods for the accurate identification of S. epidermidis. First, multiplex PCR was performed using designed primers for housekeeping genes Gmk2 and pta, and also SESB gene of S. epidermidis. To investigate the specificity of multiplex PCR, DNA of the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii were used as negative controls. …show more content…
epidermidis. At least, sufficient concentration for amplifying was 5 ng/ L of DNA of S. epidermidis. Also, in this study gold nanoparticles probes were used for colorimetric detection of S. epidermidis. Two 20-base thiolated probes were prepared based on the sequence of pta housekeeping gene of S. epidermidis. Genomic DNA of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii were used as negative controls and no alteration was detected. To investigate the sensitivity of the gold nanoparticles probes, we used different concentrations of the extracted DNA from S. epidermidis. At least, sufficient concentration for alteration color and absorption of solution was 15 ng/ L. Our results revealed that both methods were sufficiently specific and sensitive to detect S.