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Updated: Aug 22, 2026
Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Epidemiological typing of community-acquired methicillin-resistant Staphylococcus aureus isolates from children in
Chih-Chien Wang1, Wen-Tsung Lo, Mong-Ling Chu
1Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. ndmcccw@yahoo.com.tw
Insights
A dominant community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strain with high macrolide resistance is prevalent in Taiwan. Most children improved with drainage, despite ineffective antibiotic treatment, indicating a need to update guidelines.
Area of Science:
- Infectious Diseases
- Epidemiology
- Microbiology
Background:
- Epidemiological study of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in hospitalized children.
- Conducted over a 5-year period at a 1400-bed tertiary medical center in northern Taiwan.
Purpose of the Study:
- To investigate the characteristics of CA-MRSA infections in pediatric patients.
- To determine antimicrobial resistance patterns and genetic relatedness of CA-MRSA isolates.
Main Methods:
- Nineteen previously healthy children with CA-MRSA infections were enrolled.
- Seventeen CA-MRSA isolates underwent antimicrobial susceptibility testing and molecular typing (pulsed-field gel electrophoresis, multilocus sequence typing).
Main Results:
- Uniformly high macrolide resistance (100%) was observed in CA-MRSA isolates.
- All isolates possessed the ermB gene and the macrolide-lincosamide-streptogramin-constitutive phenotype.
- Molecular typing revealed a predominant CA-MRSA strain (ST59) in 65% of isolates, with detection of lukS-PV and lukF-PV toxin genes.
Conclusions:
- A single, endemic CA-MRSA strain with high macrolide resistance dominates the community.
- Clinical improvement occurred with incision and drainage, even with ineffective antibiotics, suggesting a need to revise treatment guidelines.
Background:
A 1400-bed tertiary medical center in northern Taiwan was used to conduct an epidemiological study of children hospitalized with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection during a 5-year period.
Methods:
Nineteen previously healthy children with predominantly skin and soft-tissue CA-MRSA infections were enrolled into the study. Seventeen CA-MRSA isolates were examined for antimicrobial susceptibility and molecular typing.
Results:
A comparison of our results with the reported resistance rates among CA-MRSA isolates from other countries showed uniformly high macrolide resistance (100%). Of the 17 MRSA isolates in our study, all had the macrolide-lincosamide-streptogramin-constitutive phenotype and the ermB gene. Moreover, on the basis of molecular typing results, 11 (65%) of 17 CA-MRSA isolates were genetically related (as determined by pulsed-field gel electrophoresis), and multilocus sequence typing revealed a sequence type of 59 in all isolates. Staphylococcal toxin genes lukS-PV and lukF-PV were detected in all isolates. However, staphylococcal cassette chromosome mec type IV was only detected in 3 (17.6%) of 17 isolates; the remaining 14 isolates were untypeable.
Conclusions:
Analysis of our data suggests the predominance of a single endemic CA-MRSA strain with high macrolide resistance in our community. Clinical improvement with incision and drainage was noted for most patients, despite treatment with an ineffective antibiotic, so the need for a change in treatment guidelines should be addressed.
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