基于全基因组测序的院内耐碳青霉烯肺炎克雷伯菌耐药性及 同源性分析.

Objective：Based on genomics，this study aims to investigate the distribution of drug-resistant genes，virulence factors， and homology analysis of the hospital isolated carbapenem resistant Klebislla. pneumoniae strains. The molecular mechanisms of nosocomial infections will be elucidated to provide laboratory evidence for the clinical treatment and prevention of multidrug-resistant strains. Methods：A clinical isolate of carbapenem-resistant pan-drug-resistant Klebislla. pneumoniae (KPX) was collected，cultured， and identified. The minimum inhibitory concentrations (MICs) of commonly used antibiotics were determined，and multilocus sequence typing (MLST) was performed for genetic typing，followed by whole-genome sequencing. Based on the results of the genetic sequencing，selected relevant resistance genes for amplification detection in an additional 50 clinical isolates of carbapenem-resistant KPX，verified their carriage status，and further elaborate on the sequencing results. Results：The drug sensitivity test showed that the KPX strain was resistant to all antibiotics except colistin and tigecycline. The sequencing results relevant that the chromosomal gene sequence of this bacterium is 5 468 925 bp in length and contains four plasmids (179 972 bp，141 377 bp，85 181 bp，and 20 247 bp) . It had a total of 5 984 protein-coding genes，85 tRNA genes，and 25 rRNA operons. Additionally，this bacterium carried a large number of resistant genes involved in encoding multiple antibiotics. MLST results indicated that the genetic type of this bacterium is ST11，and most of its sequences are similar to previously reported strains in Sichuan and Hangzhou. The closest match was a strain with the code SCKP020029 (NCBI accession number：CP029384) of Klebislla. pneumoniae. The additional 50 carbapenem-resistant Klebislla. pneumoniae collected were confirmed to produce extended-spectrum beta-lactamases (ESBLs),with 97% being of ST11. Pulsed-field gel electrophoresis (PFGE) results showed that they belonged to three different clones. Among these strains，the detection rates of resistance genes were as follows：KPC-2 (98%),SHV-11 (98%),TEM-1 (76%),CTX -M (76%),Oqxb1 (66%),qnrS (70%),Int1 (42%),sul1 (82%),sul2 (96%),iutA (88%),iucABCD (10%),and rmpA2 (100%) . Conclusion：The experimental results revealed that a high degree of genomic similarity among nosocomial carbapenem resistant Klebislla. Pneumoniae strains，with epidemiological characteristics of both clustering and sporadic cross -infection. Antimicrobial-resistance profiles suggested the presence of significant selective antibiotic pressure. Furthermore，the dissemination of plasmid -mediated resistance genes among bacteria indicates that the spread of these resistant strains within the hospital is primarily through plasmid transfer. Effective monitoring, isolation，and control of these plasmids are essential measures to reduce the spread of bacterial resistance in nosocomial infections. [ABSTRACT FROM AUTHOR]