Jpn. J. Infect. Dis., 53 (2), 86-87, 2000

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Laboratory and Epidemiology Communications

Comparision of Genomic DNA Fingerprinting Using Pulsed-Field Gel Electrophoresis and Antibiotic Susceptibility of Clinical Isolates of Methicillin-Resistant Staphylococcus aureus between Chiang Mai and Tokyo

Prasit Tharavichitkul1, Fumiko Kirikae2, Aki Kaneko2, Masahito Hashimoto2, Kiminori Toyooka2, Mitsuharu Hasegawa2, Kuniko Iwata2, Tadatoshi Kuratsuji2, Yoshio Yazaki2, Thira Sirisanthana3 and Teruo Kirikae2*

1Department of Microbiology and 3Deparment of Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand and 2International Medical Center of Japan, Toyama 1-21-1, Shinjuku, Tokyo 162-8655

Communicated by Hiroshi Yoshikura

(Accepted May 26, 2000)

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in both Thailand and Japan (1-3). Genomic DNA fingerprinting using pulsed-field gel electrophoresis (PFGE) is a powerful tool to investigate the source, transmission, and spread of MRSA infection (4).

Nine and sixteen MRSA isolates obtained respectively from patients in a university hospital in Chiang Mai, Thailand (January to February 2000) and from patients in a hospital (with about 900 beds) in Tokyo (February 1999 to February 2000) were analyzed for chromosomal DNA type (contour-clamped homogeneous electric field system; CHEF MapperTM: Bio-Rad Laboratories, Hercules, Calif., USA), antibiotic resistance (WalkAwayTM, Dade Behring, Deerfield, Ill., USA), enterotoxin serotype (SET-RPLA: Denka Seiken Co., Tokyo), toxic shock syndrome toxin-1 (TSST-1) production (TST-RPLA: Denka Seiken), and coagulase serotype (Denka Seiken).

Isolates from Chiang Mai showed 5 different PFGE patterns and 7 different antibiotic patterns (Fig. 1 and Table 1). Band-based cluster analysis of PFGE patterns (Molecular AnalystTM: Bio-Rad) revealed a more than 94% similarity among the five isolates (Fig. 2). Chiang Mai isolates with PFGE pattern A, but not those with other PFGE patterns, produced enterotoxin (Table 2). The produced enterotoxin was type A. All the isolates produced coagulase type IV, but not TSST-1.

All the 16 isolates from Tokyo showed different PFGE patterns, yet the similarity was more than 94%. Eight different antibiotic patterns were revealed (Fig. 2 and Table 1). Most Tokyo isolates produced enterotoxin type C, coagulase type II, and TSST-1. The cluster analysis of PFGE pattern revealed that similarity within individual hospitals was high while similarity between Chiang Mai and Tokyo isolates was low (Fig. 2). Antibiotic patterns were different between Chiang Mai and Tokyo isolates except for pattern Ta (Ja). MRSAs isolated in Thailand and those isolated in Japan were thus quite different in terms of their biological and genomic properties.

REFERENCES

  1. Sirisanthana, T., Tharavichitkul, P. and Baosoung, V. (1987): Tolerance to cephalothin in strains of Staphylococcus aureus isolated from blood cultures. J. Med. Assoc. Thai. 70, 228-233.
  2. Kaneko, A., Miyazawa, H., Kirikae, F., Toyooka, K., Hashimoto, M., Yamasaki, S., Hasegawa, M., Takeuchi, C., Kuratsuji, T., Sumiya, M., Kobori, O., Yazaki, Y. and Kirikae, T. (2000): Epidemiological analysis of methicillin-resistant Staphylococcus aureus outbreaks in a neonatal intensive care unit by genomic DNA fingerprinting using pulsed-field gel electrophoresis. Jpn. J. Infect. Dis. 53, 82-84.
  3. Kaneko, A., Kimura, S., Kirikae, F., Toyooka, K., Hashimoto, M., Hashimoto, M., Hasegawa, M., Mezaki, M., Kuratsuji, T., Sumiya, M., Kobori, O., Yazaki, Y. and Kirikae, T.(2000): Epidemiological analysis of a methicillin-resistant Staphylococcus aureus outbreak in a surgery ward by genomic DNA fingerprinting using pulsed-field gel electrophoresis. Jpn. J. Infect. Dis. 53, 84-85.
  4. Ichiyama, S., Ohta, M., Shimokata, K., Kato, N. and Takeuchi, J. (1991): Genomic DNA fingerprintings by pulsed-field gel electrophoresis as an epidemiological marker for study of nosocomial infections caused by methicillin-resistant Staphylococcus aureus. J. Clin. Microbiol., 29, 2690-2695.



*Corresponding author: Fax: +81-3-3202-7364, E-mail: tkirikae@ri.imcj.go.jp


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