臺大醫院-內科部;臺大醫學院-微生物學科暨研究所;Lin, Tzu-LungTzu-LungLinPan, Yi-JiunYi-JiunPanHsieh, Pei-FangPei-FangHsiehHsu, Chun-RuChun-RuHsuWu, Meng-ChuanMeng-ChuanWuJIN-TOWN WANG2017-02-152018-07-112017-02-152018-07-112016http://ntur.lib.ntu.edu.tw//handle/246246/270670Analysis 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 protospacer 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.[SDGs]SDG310.1038/srep31644