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Published on: September 5, 2013
High hemolytic activity of the Staphylococcus aureus spa t1081 among clonal complex 45 in Taiwan
Yu-Tzu Lin1, Chun-Li Lee2, Chin-Yun Lin1
1Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan.
Background:
Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 was first reported in Taiwan in 2006. Since then, the prevalence of ST45 MRSA in clinical isolates has increased. This study was carried out to understand the changes in the proportions, evolutionary relationships, and infection advantages of ST45 and its related clones.
Materials And Methods:
S. aureus including MRSA and MSSA (methicillin-sensitive S. aureus), and clonal complex (CC) 45 blood isolates were collected in 2000, 2005, and from January 2010 to August 2014. Molecular typing, multiple-locus variable-number tandem repeat analysis (MLVA) and single nucleotide polymorphism (SNP)-based phylogenetic analysis were performed. Fitness and virulence analyses were used to understand the infection advantages of the isolates.
Results:
Among the 67 CC45 isolates, only MSSA ST508 isolates were found in 2000 and 2005. Since 2010, the prevalence of MRSA has increased, t1081/ST45 has become dominant, and MRSA ST508 has been found. Phylogenetic analysis indicated that most of the ST45 isolates were located in a cluster distinct from those of ST508 and ST929. However, the t026 isolates clustered with the ST508 isolates rather than with the other ST45 isolates. Moreover, fitness and virulence analyses revealed that the t1081 isolates had higher hemolytic activity than the t026 and ST508 isolates did.
Conclusion:
Our findings indicated that the increased prevalence of ST45 MRSA isolates from blood cultures in Taiwan was due to the t1081 isolates, and their high hemolytic activity may provide an infection advantage.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) ST45 blood infections in Taiwan are increasing due to the dominant t1081 clone. This MRSA clone exhibits higher hemolytic activity, potentially enhancing its ability to cause infection.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 emerged in Taiwan in 2006.
- Increasing prevalence of ST45 MRSA in clinical isolates necessitates understanding its evolution and virulence.
Purpose of the Study:
- To investigate the changing proportions of ST45 MRSA and related clones.
- To analyze the evolutionary relationships and infection advantages of these isolates.
Main Methods:
- Collection of Staphylococcus aureus isolates (MRSA and MSSA) from blood cultures between 2000 and 2014.
- Utilized molecular typing, MLVA, and SNP-based phylogenetic analysis.
- Conducted fitness and virulence assays to assess infection advantages.
Main Results:
- The t1081/ST45 clone became dominant in MRSA isolates after 2010.
- Phylogenetic analysis revealed distinct clustering for ST45 isolates compared to ST508 and ST929.
- The t1081 isolates demonstrated significantly higher hemolytic activity than other CC45 variants.
Conclusions:
- The rise of ST45 MRSA in Taiwanese blood cultures is attributed to the t1081 clone.
- Elevated hemolytic activity of the t1081 clone likely confers an infection advantage.
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