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Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Population deviation of piggery-associated methicillin-resistant Staphylococcus aureus based on mec-associated direct
Min Tao Wan1, Tsai Ling Lauderdale, Nobumichi Kobayashi
1School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
Abstract:
Piggery-associated methicillin-resistant Staphylococcus aureus (MRSA) is a potential zoonotic pathogen. We constructed the population structure and dynamics of staphylococcal chromosome cassette mec (SCCmec) in MRSA ST9 isolates from different geographical areas of Taiwan. A total of 140 MRSA (135 piggery and 5 human clinical) isolates from three populations located in western Taiwan (n=96 including the 5 clinical isolates), central eastern Taiwan (n=22), and Penghu Island (n=22) were collected and characterized by analysis of the mec-associated direct repeat unit (dru). Twenty-eight dru types (with 24 novel) and 15 dru-Clonal Complexes (CCs) were identified. The predominant novel dt12w type (48.6%) was widespread in all populations and may have a superior ability to transmit among populations. The minimum spanning network showed that at least two ancestral dru types (dt11a and dt12w) were identified, and the genetics between different populations could be differentiated. Temporal distributions of clone population dynamics estimated through the Bayesian skyline plot indicated a stable population with a long evolutionary history for MRSA ST9 in Taiwan. Findings indicating that some dru types are shared between piggery-associated and human-clinical MRSA ST9 suggest the occurrence of cross-species horizontal transmission of SCCmec.
Insights
Piggery-associated methicillin-resistant Staphylococcus aureus (MRSA) ST9 in Taiwan shows diverse staphylococcal chromosome cassette mec (SCCmec) types. Some SCCmec types shared between pigs and humans indicate potential zoonotic transmission.
Area of Science:
- Veterinary Microbiology
- Zoonotic Diseases
- Molecular Epidemiology
Background:
- Piggery-associated methicillin-resistant Staphylococcus aureus (MRSA) poses a zoonotic risk.
- Understanding the population structure and dynamics of MRSA's staphylococcal chromosome cassette mec (SCCmec) is crucial for tracking transmission.
Purpose of the Study:
- To investigate the population structure and dynamics of SCCmec in MRSA ST9 isolates from Taiwanese piggeries and human clinical cases.
- To identify novel SCCmec types and assess their geographical distribution and potential for cross-species transmission.
Main Methods:
- Analysis of 140 MRSA ST9 isolates (135 piggery, 5 human clinical) from three Taiwanese regions.
- Characterization using mec-associated direct repeat unit (dru) typing.
- Minimum spanning network and Bayesian skyline plot analyses for population structure and temporal dynamics.
Main Results:
- Twenty-eight dru types, including 24 novel ones, and 15 dru-Clonal Complexes (CCs) were identified.
- A predominant novel type, dt12w, was widespread across all sampled populations.
- Genetic differentiation between populations was observed, with at least two ancestral dru types identified.
Conclusions:
- MRSA ST9 in Taiwan exhibits a stable population with a long evolutionary history.
- Shared dru types between piggery and human MRSA ST9 isolates suggest cross-species horizontal transmission of SCCmec.
- The widespread dt12w type may possess enhanced transmissibility among populations.
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