Fine typing of methicillin-resistant Staphylococcus aureus isolates using direct repeat unit and staphylococcal...

Area of Science:

• Microbiology
• Epidemiology
• Molecular Biology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) typing is vital for epidemiological surveillance and outbreak prevention.
• Evaluating the efficiency of different typing methods for specific MRSA isolates is essential but infrequently performed.

Purpose of the Study:

• To assess and compare the discriminatory power of five molecular typing methods for 157 MRSA isolates from Taiwan.
• To determine the effectiveness of SCCmec, MLST, spa, dru, and SIRU typing for characterizing MRSA isolates.

Main Methods:

• 157 MRSA isolates from Taiwan were analyzed using SCCmec typing, multilocus sequence typing (MLST), spa typing, mec-associated direct repeat unit (dru) copy number determination, and staphylococcal interspersed repeat unit (SIRU) profiling.
• Comparative analysis of the discriminatory power of each method was performed.

Main Results:

• Four SCCmec types, eight MLST types, 15 spa types, 11 dru types, and 31 SIRU profiles were identified.
• SCCmec type III was the most common (73.2%), followed by ST239 (63.1%), t037 (68.2%), 14 dru copies (48.4%), and SIRU profile 3013722 (65%).
• Dru and SIRU typing demonstrated superior discriminatory power for SCCmec type III and SCCmec types IV and VT isolates, respectively.

Conclusions:

• While overall discrimination was similar across methods, dru and SIRU typing provide enhanced resolution for specific MRSA SCCmec types.
• These findings suggest that dru and SIRU typing can be valuable adjuncts for detailed characterization of certain MRSA isolates.
• Improved typing resolution aids in more precise epidemiological tracking and outbreak management of MRSA.