title: Changing trends in antimicrobial susceptibility of Streptococcus pneumoniae isolates in Taiwan, 2006-2007.
abstract: BACKGROUND
  Multiple antibiotic-resistant clones of Streptococcus pneumoniae have spread throughout the world and continue to evolve under the selective pressure of antibiotics and vaccines. The aim of this study is to assess the susceptibility of S. pneumoniae isolates and to analyze the resistance trends in Taiwan.
  
  
  METHODS
  Antimicrobial susceptibility tests were performed on 152 nonmeningeal isolates of S. pneumoniae that were collected from 13 different hospitals around Taiwan from 2006-2007. Tests were performed using the broth microdilution method according to recommendations of the Clinical and Laboratory Standards Institute.
  
  
  RESULTS
  The minimal inhibitory concentrations (MIC(50)/MIC(90)) of penicillin, cefotaxime, vancomycin, and moxifloxacin were 0.5/1.0, 0.25/1.0, 0.25/0.5, and 0.06/0.12 μg/mL, respectively. The susceptibility rates of penicillin, cefotaxime, vancomycin, and moxifloxacin were 99.3%, 99.3%, 100%, and 98.7%, respectively. However, if the meningitis breakpoints were applied to these nonmeningeal isolates, the susceptibility rates of penicillin and cefotaxime were reduced to 18.4% and 76.3%, respectively. Compared with the findings from previous studies in Taiwan, our results show that the percentage of S. pneumoniae isolates with a penicillin MIC of 0.12-1.0 μg/mL increased from 43.3% in 1996-1997 to 73.7% in 2006-2007 (p < 0.001). The percentage of S. pneumoniae isolates with a cefotaxime MIC of 1.0 μg/mL increased from 11.3% in 1996-1997 to 23.0% in 2006-2007 (p < 0.001). Regarding the serial MIC intervals of the four antimicrobial agents, there was no significant difference between bacteremic and nonbacteremic isolates.
  
  
  CONCLUSIONS
  Although nonmeningeal S. pneumoniae isolates remained susceptible to penicillin, the proportion of isolates with a penicillin MIC of 0.12-1.0 μg/mL or cefotaxime MIC of 1.0 μg/mL increased during the past decade in Taiwan. The ever-increasing resistance of S. pneumoniae has a great impact on the treatment of meningitis.
authors.affiliation: Section of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Chien-Feng
authors.initials: CF
authors.lastname: Li
authors.forename: Meei-Fang
authors.initials: MF
authors.lastname: Liu
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Shi
authors.forename: Po-Ren
authors.initials: PR
authors.lastname: Hsueh
authors.forename: Chun-Hsing
authors.initials: CH
authors.lastname: Liao
authors.forename: Tsrang-Neng
authors.initials: TN
authors.lastname: Jang
authors.forename: Shih-Ming
authors.initials: SM
authors.lastname: Tsao
authors.forename: Hsiang-Chi
authors.initials: HC
authors.lastname: Kung
authors.forename: Gwo-Jong
authors.initials: GJ
authors.lastname: Hsu
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Cheng
authors.forename: Hsiu-Chen
authors.initials: HC
authors.lastname: Lin
authors.forename: Yung-Ching
authors.initials: YC
authors.lastname: Liu
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chuang
authors.forename: Lih-Shinn
authors.initials: LS
authors.lastname: Wang
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology; D001372:Aza Compounds / Q000494:pharmacology; D002439:Cefotaxime / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D024841:Fluoroquinolones; D006801:Humans; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D010406:Penicillins / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification*; D013624:Taiwan; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D010406:Penicillins; D011804:Quinolines; D014640:Vancomycin; D002439:Cefotaxime; D000077266:Moxifloxacin