title: Vancomycin-tolerant Streptococcus pneumoniae in Korea.
abstract: A nationwide surveillance study was undertaken to monitor antimicrobial resistance among clinical isolates of Streptococcus pneumoniae in Korea, with a special focus on vancomycin tolerance. For the 6-month period from March to August 2002, clinical isolates of S. pneumoniae were collected from 11 university hospitals and 1 reference laboratory. One-hundred eighty-eight isolates were measured for lysis rates after exposure to vancomycin for 4 h. Two vancomycin-tolerant S. pneumoniae (VTSP) strains, S3 and H8, were isolated from sputum cultures of two patients, who had stayed in intensive-care units of different hospitals with long-term antibiotic therapy and were not treated for pneumococcal pneumonia. The penicillin, cefotaxime, and vancomycin MICs for S3 were 8 microg/ml, >16 microg/ml, and 0.5 microg/ml, and those for H8 were 2 microg/ml, 2 microg/ml, and 0.5 microg/ml, respectively. While S3 belonged to serotype 23F and was autolysin defective, H8 belonged to serotype 13F and had intact autolysin. These strains were not clonally related as determined by pulsed-field gel electrophoresis of chromosomal DNA. In agreement with previous reports, both isolates showed pairing of TIGR4 vex2 with R6 pep27 and had two identical amino acid substitutions, Q441K in vncS and N25D in vex2. These findings indicate that two VTSP strains have emerged independently in Korea, suggesting a prevalence rate of 1.1%. The emergence of VTSP would be a serious threat in Korea, where there are significant rates of penicillin resistance in S. pneumoniae. Monitoring of the prevalence of VTSP and further investigation of the clinical relevance of VTSP are warranted.
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, 388-1 Pungnap-dong, Songpa-ku, Seoul 138-736, Korea.
authors.forename: Heungsup
authors.initials: H
authors.lastname: Sung
authors.forename: Hee Bong
authors.initials: HB
authors.lastname: Shin
authors.forename: Mi-Na
authors.initials: MN
authors.lastname: Kim
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Lee
authors.forename: Eui-Chong
authors.initials: EC
authors.lastname: Kim
authors.forename: Wonkeun
authors.initials: W
authors.lastname: Song
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Jeong
authors.forename: Wee-Gyo
authors.initials: WG
authors.lastname: Lee
authors.forename: Yeon-Joon
authors.initials: YJ
authors.lastname: Park
authors.forename: George M
authors.initials: GM
authors.lastname: Eliopoulos
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D006801:Humans; D007723:Korea / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D011159:Population Surveillance; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification* / Q000378:metabolism; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins