Role of Polymerase Chain Reaction (PCR) in the detection of antibiotic-resistant Staphylococcus aureus

Abstract

Background: Staphylococcus aureus is mainly acquired from hospital infections and demonstrated the ability of developing resistance to many antibiotics. Polymerase Chain Reaction (PCR) was used to identify antibiotic-resistant isolates. This study was conducted in Al-Mujtahed, Al-Mouwasat and the Children Hospitals in Damascus during the period between January and June in 2013.
Objectives: This study aimed to investigate S. aureus in some clinical samples by PCR and study the bacterial resistance to some antibiotics.
Materials and methods: DNA fragments were amplified from isolated DNA. PCR was used to amplify the sequences of 16S rRNA, gap gene and nuc gene depending on six specific primers. The PCR products were detected by agarose gel electrophoresis. The antibiotics susceptibility tests were conducted on all isolates using the Kirby-Bauer disk diffusion method on Mueller Hinton agar and Luria Bertani (LB) Agar.
Results: Eighty one isolates of S. aureus were collected from blood samples, urine samples and bronchial secretions. The results showed that the DNA fragments of 16S rRNA, gap gene and nuc gene were approximately equal to 479 bp, 933 bp and 270 bp, respectively and the results of antibiotics resistance for the 10 tested antibiotics were as following: Chloramphenicol (97.5%), Tetracycline (50.6%), Cefuroxime (37.0%), Oxacillin (33.3%), Levofloxacin (37.0), Erythromycin (35.8%), Ciprofloxacin (32.1%), Rifampicin (7.4%), Vancomycin (3.7%), Imipenem (0%).
Conclusion: This study showed that the PCR is a specific and effective method for classifying and identifying isolates of S. aureus, which demonstrated increasing resistance against many antibiotics.

Keywords: S. aureus; 16S rRNA; Gap gene; Nuc gene; PCR; Antibiotics