| Title | Genetic Relatedness within Streptococcus pneumoniae Serotype 19F and 23F Isolates in Korea by Pulsed-Field Gel Electrophoresis |
|---|---|
| Author | Kwang Jun Lee, Song Mee Bae, Kyu Jam Hwang, Young Hee Lee, and Ki Sang Kim * |
| Address | Laboratory of Respiratory Infections, Department of Bacteriology, National Institute of Health, Seoul, Korea (Received October 28, 2002 / Accepted December 30, 2002) |
| Bibliography | Journal of Microbiology, 41(1),1-6, 2003, |
| DOI | |
| Key Words | pulsed-field gel electrophoresis, PFGE, serotype 19F, serotype 23F, multi-drug resistance |
| Abstract | The genetic relatedness of multidrug-resistant pneumococcal isolates of serotypes 19F and 23F was investigated. The DNA fragments digested with Sma I were resolved by pulsed-field gel electrophoresis (PFGE). PFGE analysis of 36 S. pneumoniae isolates showed 13 different patterns. Among 22 isolates of serotype 19F, 9 different PFGE patterns were present and 14 isolates of serotype 23F isolates represented 5 distinct PFGE patterns. Two isolates of serotype 19F and six isolates of serotype 23F shared the same PFGE pattern (Pattern I). Based on the genetic relatedness within the strains (one genetic cluster was defined as having more than 85% homology), we divided the pneumococcal strains into 6 genetic clusters (I, II, III, IV, V, and VI). The 22 strains of serotype 19F belonged to five distinct genetic clusters (I, II, III, IV, V and VI) and 14 strains of serotype 23F represented two genetic clusters (I and II ). These results showed that strains of serotype 19F are genetically more diverse than those of serotype 23F. Serotype 19F isolates with PFGE patterns H and I appeared to be less related to those of the remaining PFGE patterns (A to G) (less than 60% genetic relatedness), but those strains were genetically closely related with serotype 23F. These results suggest that the latter isolates originated from horizontal transfer of the capsular type 19F gene locus to 23F pneumococcal genotypes. In conclusion, the multidrug-resistant pneumococcal isolates of serotype 19F and 23F isolated in Korea are the result of the spread of a limited number of resistant clones. |
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