Nizhny Novgorod scientific and research institute of epidemiology and microbiology name acad. I.N. Blokhina of the Rospotrebnadzor.
Klin Lab Diagn. 2022 Mar 25;67(3):186-192. doi: 10.51620/0869-2084-2022-67-3-186-192.
The characteristics of resistome and virulome structure of four carbapenem-resistant Klebsiella pneumoniae clinical strains are present in the work. Two strains belonged to the sequence-type ST395, one strain - ST2262, one strain - to the new sequence-type 5816. The genes of fimbriae, enterobactin, beta-lactamase SHV type, resistance to fosfomycin fosA and transport of fluoroquinolones oqxAB in all Klebsiella strains chromosome structure were identified. The determinants of yersineobactin and aerobactin are enriched the virulome of ST395 NNKP315 and NNKP343 strains. The aerobactin genes are located on IncHI1B plasmids (IncHI1B/FIB) which highly homologous to the virulence pLVPK and pK2044 plasmids. IncR, IncL, IncQ plasmids carrying blaOXA-48, blaCTX-M-15, blaOXA-1, blaTEM-1, qnrS1, tetA, sul1, dfrA1, aac(6 ')-Ib-cr, catA1, catB3 etc. were identified in these strains. As a result of in silico analysis, an assumption about the localization of the blaOXA-48 in the structure of the IncHI1B plasmid of NNKP315 strain was made. This plasmid also contains the aminoglycosidases genes inserted into a class 1 integron In822. The mutations were found in the porin proteins OmpK35, OmpK36 and OmpK37 genes, which increases the carbapenem resistance. The virulome of NNKP16 (ST2262) strain additionally includes of the iron utilization system kfuABC chromosomal genes, and the virulome of NNKP15 (ST5816) strain contains of the capsular polysaccharide kvgAS and microcin E492 genes. Additional determinants of resistance were not identified in the resistome structure of K. pneumoniae NNKP16 and only the blaCTX-M-15 gene was found in the NNKP15 strain. The absence of acquired resistance genes seems to be due to the presence of the type I-E CRISPR-Cas system. Multiple drug resistance of the studied strains is associated with mutations identified in the gene structure of porin proteins OmpK36 and OmpK37, as well as the activity of efflux systems. It was showed the stop codon formation in the nucleotide sequence of the regulatory gene ramR to both strains, which can potentially provide overexpression of AcrAB efflux proteins.
本工作呈现了 4 株耐碳青霉烯类肺炎克雷伯菌临床株的耐药组和毒力组结构特征。2 株菌属于序列型 ST395，1 株菌属于 ST2262，1 株菌属于新序列型 5816。所有肺炎克雷伯菌株的染色体结构中均鉴定到了菌毛、enterobactin、β-内酰胺酶 SHV 型、磷霉素 fosA 耐药和氟喹诺酮类 oqxAB 转运的基因。ST395NNKP315 和 NNKP343 菌株的毒力组中富集了yersineobactin 和 aerobactin 的决定子。aerobactin 基因位于 IncHI1B 质粒（IncHI1B/FIB）上，该质粒与毒力质粒 pLVPK 和 pK2044 高度同源。在这些菌株中还鉴定到了携带 blaOXA-48、blaCTX-M-15、blaOXA-1、blaTEM-1、qnrS1、tetA、sul1、dfrA1、aac(6 ')-Ib-cr、catA1、catB3 等的 IncR、IncL、IncQ 质粒。通过计算机分析，提出了 NNKP315 菌株的 IncHI1B 质粒中 blaOXA-48 定位的假设。该质粒还包含插入到 class 1 整合子 In822 中的氨基糖苷酶基因。在孔蛋白 OmpK35、OmpK36 和 OmpK37 基因中发现了突变，这增加了碳青霉烯类的耐药性。NNKP16（ST2262）菌株的毒力组还包含了铁利用系统 kfuABC 染色体基因，而 NNKP15（ST5816）菌株的毒力组包含了荚膜多糖 kvgAS 和微菌素 E492 基因。在 K. pneumoniae NNKP16 的耐药组结构中未发现其他耐药决定子，仅在 NNKP15 菌株中发现了 blaCTX-M-15 基因。研究菌株的多重耐药性与孔蛋白 OmpK36 和 OmpK37 基因结构中鉴定到的突变以及外排系统的活性有关。在这两个菌株的调节基因 ramR 的核苷酸序列中都形成了终止密码子，这可能导致了 AcrAB 外排蛋白的过度表达。
