Same-day Detection of Methicillin Resistance in <i>Staphylococcus aureus</i> Isolates by StaResMet^® Kit

Abstract

Background: Staphylococcus aureus is an important cause of hospital-acquired infections. The most important issue with S. aureus is that the isolates are getting increasingly methicillin-resistant. Rapid differentiation between methicillin-resistant and methicillin-susceptible S. aureus species is necessary to optimize treatment and minimize costs. Objectives: The current study aimed at evaluating the StaResMet® kit for rapid detection of methicillin resistance in S. aureus isolates. Methods: A total of 217 methicillin-resistant S. aureus (MRSA) and 252 methicillin-susceptible S. aureus (MSSA) isolates were tested using the StaResMet® kit. The test was performed according to the manufacturer’s instructions. Results: The kit identified the MRSA isolates with 100% accuracy, and found that the minimum inhibitory concentrations (MICs) was > 32 µg/mL cefoxitin for 133 of the isolates, 32 µg/mL cefoxitin for 49, 16 µg/mL cefoxitin for 8, and 8 µg/mL cefoxitin for 11 of the isolates. Likewise, all 177 MSSA isolates were correctly identified using the kit, and the MICs against them were determined within the range of 1 to 4 µg/mL cefoxitin. The MIC of cefoxitin can be determined in 6 hours using the StaResMet® kit. Conclusions: The obtained results indicated that the StaResMet® kit allowed the detection of MRSA isolates rapidly and reliably, and could be a valuable tool for microbiology laboratories with limited facilities. Authors believed that the routine use of this time-saving and easy-to-use test contributes to rapid clinical diagnoses and treatments.