Molecular Subtyping of Salmonella enterica Serovar Paratyphi A from Southeast Asia

TZU-MING PAN*, CHEIN-SHENG LIN, TIEN-KWEI WANG, JIN-LAI TSAI, SU-ING HO AND CHIH-LUNG LEE

Bacteriology Division, National Institute of Preventive Medicine, Taipei, Taiwan 11513, R.O. C.

ABSTRACT

   From 1987 to 1996, forty-two isolates of Salmonella paratyphi A were collected from Taiwan, China and other Southeast Asian countries. Pulsed-field gel electrophoresis (PFGE) was used to differentiate the genomic DNA of these isolates with four different restriction enzymes, Xba I, Not I, Spe I and Avr II. Based on the PFGE profiles obtained, Avr II allowed the most discriminatory results among these restriction endonucleases. By Avr II digestions, 42 isolates of S. paratyphi A were differentiated into three clones. The predominant clone accounted for 85.7% of the tested strains (36 in 42 isolates) and was found in many countries of Southeast Asia. Thus, S. paratyphi A appears to have limited genetic diversity in evolutionary process.

Key words: S. paratyphi A, pulsed-field gel electrophoresis, restriction endonucleases, Southeast Asia