■在染色体中携带acrAB-tolC基因的临床肺炎克雷伯菌菌株的出现,随着质粒上blaKPC-2和blaCTX-M-65基因的两个重复串联核心结构的存在,提出了重大的临床挑战。
为了研究肺炎克雷伯菌菌株SC35的详细遗传特征,使用Illumina和纳米孔平台对细菌染色体和质粒进行了测序。此外,采用生物信息学方法分析与抗生素抗性基因相关的可移动遗传元件。
■K.发现肺炎菌株SC35具有A类β-内酰胺酶,并对所有测试的抗生素具有抗性。这种抗性归因于外排泵基因的存在,特别是acrAB-tolC,在SC35染色体上。此外,SC35质粒p1携带blaKPC-2和blaCTX-M-65的两个重复串联核心结构,以及带有rmtB的blaTEM-1,与In413、Tn3和TnAs3等可移动遗传元件共享重叠结构。通过质粒转移试验,确定SC35质粒p1可以成功转移,平均接合频率为6.85×10-4。
■SC35质粒p1的结构似乎与其他质粒如pKPC2_130119、pDD01754-2和F4_质粒pA相关地进化。传染性菌株SC35对被测试的抗生素没有易感性,因此,应采取有效措施防止这种菌株的传播和流行。
UNASSIGNED: The emergence of clinical Klebsiella pneumoniae strains harboring acrAB-tolC genes in the chromosome, along with the presence of two repetitive tandem core structures for bla KPC-2 and bla CTX-M-65 genes on a plasmid, has presented a significant clinical challenge.
UNASSIGNED: In order to study the detailed genetic features of K. pneumoniae strain SC35, both the bacterial chromosome and plasmids were sequenced using Illumina and nanopore platforms. Furthermore, bioinformatics methods were employed to analyze the mobile genetic elements associated with antibiotic resistance genes.
UNASSIGNED: K. pneumoniae strain SC35 was found to possess a class A beta-lactamase and demonstrated resistance to all tested antibiotics. This resistance was attributed to the presence of efflux pump genes, specifically acrAB-tolC, on the SC35 chromosome. Additionally, the SC35 plasmid p1 carried the two repetitive tandem core structures for bla KPC-2 and bla CTX-M-65, as well as bla TEM-1 with rmtB, which shared overlapping structures with mobile genetic elements as In413, Tn3, and TnAs3. Through plasmid transfer assays, it was determined that the SC35 plasmid p1 could be successfully transferred with an average conjugation frequency of 6.85 × 10-4.
UNASSIGNED: The structure of the SC35 plasmid p1 appears to have evolved in correlation with other plasmids such as pKPC2_130119, pDD01754-2, and F4_plasmid pA. The infectious strain SC35 exhibits no susceptibility to tested antibioticst, thus effective measures should be taken to prevent the spread and epidemic of this strain.