Abstract：
The co-production of KPC and NDM carbapenemases in carbapenem-resistant Klebsiella pneumoniae (CRKP) complicates clinical treatment and increases mortality rates. The emergence of KPC-NDM CRKP is believed to result from the acquisition of an NDM plasmid by KPC CRKP, especially under the selective pressure of ceftazidime-avibactam (CZA). In this study, a CRKP-producing KPC-2 (JNP990) was isolated from a patient at a tertiary hospital in Shandong Province, China. Following sulfamethoxazole-trimethoprim (SXT) treatment, the isolate evolved into a strain that co-produces KPC and NDM (JNP989), accompanied by resistance to SXT (minimum inhibitory concentration >2/38 µg/mL) and CZA (dd ≤14 mm). Whole-genome sequencing and S1 nuclease pulsed-field gel electrophoresis revealed that JNP989 acquired an IncC plasmid (NDM plasmid) spanning 197 kb carrying sul1 and blaNDM-1 genes. The NDM plasmid could be transferred successfully into Escherichia coli J53 at a conjugation frequency of (8.70±2.47) × 10-4. The IncFⅡ/IncR plasmid carrying the blaKPC-2 gene in JNP990 could only be transferred in the presence of the NDM plasmid at a conjugation frequency of (1.93±0.41) × 10-5. Five CRKP strains with the same resistance pattern as JNP989, belonging to the same clone as JNP989, with sequence type 11 were isolated from other patients in the same hospital. Two strains lost resistance to CZA due to the loss of the blaNDM-1-carrying fragment mediated by insertion sequence 26. Plasmid stability testing indicated that the IncC plasmid was more stable than the blaNDM-1 genes in the hosts. This study describes the evolution of KPC-NDM CRKP and its spread in hospitalized patients following antibiotic treatment, highlighting the severity of the spread of resistance.
摘要：
耐碳青霉烯肺炎克雷伯菌（CRKP）中KPC和NDM碳青霉烯酶的共同产生使临床治疗复杂化并增加死亡率。KPC-NDMCRKP的出现被认为是通过KPC-CRKP获得NDM质粒的结果。特别是在头孢他啶-阿维巴坦（CZA）的选择压力下。在这项研究中,从山东省一家三级医院的一名患者中分离出产生CRKP的KPC-2（JNP990）。磺胺甲恶唑-甲氧苄啶（SXT）治疗后，分离株进化成一种产生KPC和NDM的菌株（JNP989），伴有对SXT（MIC>2/38μg/mL）和CZA（dd≤14mm）的抗性。全基因组测序（WGS）和S1脉冲场凝胶电泳（PFGE）显示，JNP989获得了一个跨越197kb的IncC质粒（NDM质粒），携带sul1和blaNDM-1基因。NDM质粒可以以(8.70±2.47)×10-4的接合频率成功转移到大肠杆菌J53中。JNP990中携带blaKPC-2基因的IncFⅡ/IncR质粒只能在NDM质粒存在下以(1.93±0.41)×10-5的接合频率转移。从同一医院的其他患者中分离出5株与JNP989耐药模式相同的CRKP菌株，与JNP989属于同一克隆,序列类型为ST11。由于由插入序列26介导的携带blaNDM-1的片段的丢失,两个菌株失去了对CZA的抗性。质粒稳定性测试表明IncC质粒在宿主中比blaNDM-1基因更稳定。我们的研究描述了KPC-NDM-CRKP的演变及其在抗生素治疗后住院患者中的传播，凸显了当前阻力蔓延的严重程度。
