Screening method for rapid detection of methicillin-resistant (heteroresistant) Staphylococcus aureus

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Staphylococcus aureus is a common pathogen causing various infections.
• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant public health threat due to its resistance to beta-lactam antibiotics.
• Accurate and rapid detection of MRSA, including heteroresistant strains, is crucial for effective treatment and infection control.

Purpose of the Study:

• To develop and evaluate a novel broth-based screening method for detecting methicillin-resistant (heteroresistant) Staphylococcus aureus.
• To assess the efficiency and accuracy of the developed method in identifying MRSA from primary culture plates.

Main Methods:

• A broth screening method was established using cation-supplemented Mueller-Hinton broth with NaCl and specific concentrations of methicillin and oxacillin.
• Lyophilized vials of the broth medium were hydrated and tested against 129 methicillin-resistant and 35 methicillin-susceptible Staphylococcus aureus strains.
• A tetrazolium indicator was added after 5 hours of incubation to facilitate the detection of resistant strains.

Main Results:

• The developed broth screening method successfully detected 96.9% of methicillin-resistant Staphylococcus aureus strains.
• The method demonstrated high specificity, with no false-positive results observed in the tested strains.
• The assay effectively identified heteroresistant strains of Staphylococcus aureus.

Conclusions:

• The novel broth screening method provides a rapid and accurate means for detecting methicillin-resistant (heteroresistant) Staphylococcus aureus.
• This method shows promise for improving the timely identification of MRSA in clinical microbiology laboratories.
• The high detection rate and absence of false positives suggest its utility in routine diagnostics and infection prevention strategies.