title: Imipenem represses CRISPR-Cas interference of DNA acquisition through H-NS stimulation in Klebsiella pneumoniae.
abstract: Analysis of the genome of Klebsiella pneumoniae NTUH-K2044 strain revealed the presence of two clustered regularly interspaced short palindromic repeats (CRISPR) arrays separated with CRISPR-associated (cas) genes. Carbapenem-resistant K. pneumoniae isolates were observed to be less likely to have CRISPR-Cas than sensitive strains (5/85 vs. 22/132). Removal of the transcriptional repressor, H-NS, was shown to prevent the transformation of plasmids carrying a spacer and putative proto-spacer adjacent motif (PAM). The CRISPR-Cas system also decreased pUC-4K plasmid stability, resulting in plasmid loss from the bacteria with acquisition of new spacers. Analysis of the acquired proto-spacers in pUC-4K indicated that 5'-TTN-3' was the preferred PAM in K. pneumoniae. Treatment of cells by imipenem induced hns expression, thereby decreasing cas3 expression and consequently repressed CRISPR-Cas activity resulted in increase of plasmid stability. In conclusion, NTUH-K2044 CRISPR-Cas contributes to decrease of plasmid transformation and stability. Through repression of CRISPR-Cas activity by induced H-NS, bacteria might be more able to acquire DNA to confront the challenge of imipenem.
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Tzu-Lung
authors.initials: TL
authors.lastname: Lin
authors.affiliation: Department of Microbiology, School of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Yi-Jiun
authors.initials: YJ
authors.lastname: Pan
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Hsieh
authors.affiliation: Department of Medical Research, E-Da Hospital, Kaohsiung, Taiwan.|School of Medicine, I-Shou University, Kaohsiung, Taiwan.
authors.forename: Chun-Ru
authors.initials: CR
authors.lastname: Hsu
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Meng-Chuan
authors.initials: MC
authors.lastname: Wu
authors.affiliation: Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan.|Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Jin-Town
authors.initials: JT
authors.lastname: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D064113:CRISPR-Cas Systems; D015780:Carbapenems / Q000494:pharmacology; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D004269:DNA, Bacterial / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016680:Genome, Bacterial; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics* / Q000472:pathogenicity; D010957:Plasmids / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D015378:Imipenem