Emergence and spread of antimicrobial resistance of Streptococcus pneumoniae in Korea

Pneumococcal resistance has become a global issue during the past three decades. One of the major foci of pneumococcal resistance worldwide is the Asian region including Korea, Japan, and Hong Kong. Korea had not been recognized as a focus of pneumococcal resistance until 1995, when serial reports documented the alarmingly high prevalence of penicillin resistance among clinical isolates. Serial reports on penicillin resistance among pneumococcal isolates in Korea ranged from 68% to 77% as of 1995. Multidrug resistance was also noted in 34% of Korean isolates. Penicillin-binding protein profile analysis, pulsed-field gel electrophoresis, ribotyping, and fingerprinting analysis of pbp genes showed that antibiotic-resistant pneumococci isolated in Korea were genetically related. Data documented the extensive spread of a resistant clone within Korea and between different countries. Besides the injudicious use of antimicrobial agents or the high prevalence of serotypes 23 and 19, the spread of a resistant clone may play an important role in the rapid increase of penicillin resistance in Korea.

Ribotyping of Multidrug-resistant Streptococcus pneumoniae from Korea and Other Countries / 감염

BACKGROUND: Recent data from Korea showed that penicillin-resistance in pneumococci was more than 70% with 35% of multidrug-resistance (MDR) among invasive isolates. One of the most important reasons for the rapid increase of pneumococcal resistance in Korea would be the spread of resistance. Previous data of pulsed-field gel electrophoresis (PFGE) and penicillin-binding protein profile suggested the spread of pneumococcal resistance. To investigate the genetic relatedness of multidrug-resistant strains, we performed the ribotyping with resistant strains isolated from different countries. METHODS: A total of 42 pneumococcal isolates from Korea(33), Spain(5), and the United States(4), which were resistant to more than 3 classes of antimicrobial agents on agar dilution methods, and a R6 penicillin-susceptible strain were used for ribotyping. Ribotyping was performed with the restriction enzyme Pvu II by using a [alpha- 32P]dCTP-labeled gene probe from Escherichia coil 16S+23S RNA. RESULTS: Ribotype of a R6 strain was quite different form those of resistant strains. A total of 12 different ribotypes were noted in multidrug-resistant strains. Nineteen of 33 Korean strain (57.6%), 3 strains from the United States (75%), and 4 strains form Spain (80%) belonged to ribotype A or A subtypes. Discriminatory index of the ribotyping was 0.83. Ribotyping produced more patterns which could denote more discriminatory power than PFGE. CONCLUSION: The data strongly suggest the genetic relatedness of resistant strains from different countries. It might suggest the spread of pneumococcal resistance within Korea, which could partly explain the rapid increase of resistance in a short period.