One step PCR for detection of Staphylococcus aureus specific sequence gene and mecA gene in Northwestern Nigerian hospitals

Introduction

Methicillin – resistant Staphylococcus aureus (MRSA) has been noted as one of the main pathogen of public health importance. Detection of the mec A gene by polymerase chain reaction (PCR) is the gold standard for identifying methicillin-resistant Staphylococcus aureus.

Objectives

In order to accelerate the procedure of identification in clinical microbiology laboratories, it is very important to havea simple and rapid method for DNA extraction. In this work, a one step PCR assay for the detection of clinically relevant antibiotic resistance gene (mec A gene) harbored by some Staphylococcus aureus isolates and for the simultaneousidentification of such isolates at the species level has been described.

Methods

In this work, a rapid method for bacterial DNA extraction directlyfrom a single colony that gave quality DNA for PCR in as littleas 15 minutes was used. PCR was used to amplify both the Staphylococcus aureus specific sequence gene and mec A gene of 100 isolates in Northwestern Nigeria with the amplicon size of 107 and 532 bp respectively. The performance and robustness of the assay was evaluated with a control strain of methicillin susceptible Staphylococcus aureus(MSSA).- ATCC 25923.

Results

All the isolates (n=100) expressed Staphylococcus aureus specific sequence gene in their PCR products. Only 5 isolates (5.0%) were confirmed as MRSA based on the detection of mec A gene. This protocol yielded good-quality target DNA for PCRamplification. Amplifications using that DNA gave rise to goodquantities of the expected PCR fragments.

Conclusion

This assay offers a rapid, simple, feasible, specific, sensitive, and accurate identification of MRSA clinical isolates and could be systematically applied as a diagnostic test in clinical microbiology laboratories, facilitating the design and use of antibiotic therapy. Hence, considering that it represents a cost-effective method and helping treatment to be initiated withoutdelay.

Disclosure of interest

None declared.