title: Differential expression of two-component systems, pmrAB and phoPQ, with different growth phases of Klebsiella pneumoniae in the presence or absence of colistin.
abstract: We explored whether expression of pmrAB, pmrD, and phoPQ is dependent on growth phase with or without colistin exposure in colistin-resistant Klebsiella pneumoniae strains. In four colistin-resistant K. pneumoniae strains, the expression of pmrAB, pmrD, and phoPQ was evaluated at mid-log, late-log, and stationary phases in the absence or presence of colistin, by qRT-PCR. The expression pattern in the presence of colistin was different from that in the absence of colistin: overall, pmrAB, pmrD, and phoPQ expressed the highest at the stationary phase in the absence of colistin, but the expression of pmrD and phoPQ decreased with the growth in the presence of colistin. Exposure to colistin might change the expression patterns of two-component regulatory systems in colistin-resistant K. pneumoniae strains.
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 440-746, Korea, soyeon0217@empas.com.
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Hyeon Jin
authors.initials: HJ
authors.lastname: Choi
authors.forename: Kwan Soo
authors.initials: KS
authors.lastname: Ko
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D003091:Colistin / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C079792:PhoQ protein, Bacteria; C409039:PmrB protein, bacteria; D014157:Transcription Factors; C081902:pmrA protein, Bacteria; C061064:PhoP protein, Bacteria; D003091:Colistin