title: Molecular epidemiological study of clinical Acinetobacter baumannii isolates: phenotype switching of antibiotic resistance.
abstract: BACKGROUND
  The presence of clinical Acinetobacter baumannii (A. baumannii) isolates with differing antibiotic resistance phenotypes in the same patient causes difficulties and confusion in treatment. This phenomenon may be caused by reasons such as cross-infection from neighboring patients that switches to different A. baumannii strain, natural mutation of A. baumannii, inducing of different antibiotic resistance genes expression or acquisition of genes conferring resistance from another source. To elucidate this question, clinical A. baumannii strains, isolated from the same individual patients, showed antibiotic resistance phenotypes switching during the same hospitalization period, were attentively collected for further analysis. Molecular approaches for phylogenetic analysis, including pulsed field gel electrophoresis, multilocus sequence typing, and short tandem repeat analysis, were employed for the chronological studies.
  
  
  RESULTS
  Our results showed that antibiotic resistance phenotype switching could have occurred as a result through both cross-infection and natural mutation roots. Our results also suggest that rapid phenotype switching between paired isolates could occur during one single course of antibiotic treatment.
  
  
  CONCLUSIONS
  Though cross infection caused antibiotic resistance phenotype switching does occur, natural mutation of A. baumannii isolates is particularly cautious for antibiotic treatment.
authors: Department of Life Science, College of Life Science, National Chung Hsing University, No, 250 Kuo-Kuang Road, Taichung 402, Taiwan, R,O,C. cchuang@dragon.nchu.edu.tw.
authors: Chang-Hua
authors: CH
authors: Chen
authors: Chieh-Chen
authors: CC
authors: Huang
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D018895:Microsatellite Repeats; D058885:Multilocus Sequence Typing; D010641:Phenotype; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial
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