1. Department of Oral Microbiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
2. Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
3. Department of Microbiology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
4. Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand