Deng Qiuyang, Zhang Jinyong, Zhang Min, Liu Zhou, Zhong Yuxin, Liu Shiyi, Cui Ruiqin, Shi Yun, Zeng Hao, Yang Xiyao, Lin Chuchu, Luo Yutian, Chen Huaisheng, Wu Weiyuan, Wu Jinsong, Zhang Tianle, Lu Yuemei, Liu Xueyan, Zou Quanming, Huang Wei
Bacteriology & Antibacterial Resistance Surveillance Laboratory, Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital, The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, Guangdong 518020, People's Republic of China.
National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China.
Infect Drug Resist. 2020 Nov 12;13:4125-4132. doi: 10.2147/IDR.S278891. eCollection 2020.
We aimed to establish a tool for rapid identification of KL49 .
Based on the capsular polysaccharide (CPS) synthesis genes database, we investigated the distribution of K locus type 49 (KL49) genes in other KL types and established a rapid identification method for KL49. We collected 61 clinical carbapenem-resistant (CRAB) strains, identified KL49 by detection, and used whole genome sequencing (WGS) for verification. A mouse pneumonia model was used to confirm the hypervirulence phenotype. We tested the presence of gene in 165 CRAB strains from three provinces in China and evaluated the correlation of carrying CRAB infection with mortality.
The gene is the CPS synthesis gene found only in KL49. We screened out nine WGS-validated KL49 strains from 61 CRAB clinical strains using polymerase chain reaction (PCR) to detect the gene. The survival rates of KL49 strains were significantly lower than nonKL49 strains in a mouse pneumonia model. The survival rates of LAC-4 knockout strain decreased significantly. Analysis of phylogenetics showed the worldwide spread of KL49 . Infection of carrying CRAB is an independent risk for mortality (OR, 10.76; 95%CI: 3.08-37.55; <0.001).
The hypervirulence phenotype of KL49 CRAB and the association with mortality highlight the urgent need for implementing control measures. The rapid identification assay has the potential to facilitate early medical intervention and worldwide surveillance.
我们旨在建立一种快速鉴定KL49的工具。
基于荚膜多糖（CPS）合成基因数据库，我们研究了K位点49型（KL49）基因在其他KL型中的分布，并建立了一种KL49的快速鉴定方法。我们收集了61株临床耐碳青霉烯类鲍曼不动杆菌（CRAB）菌株，通过检测鉴定KL49，并使用全基因组测序（WGS）进行验证。使用小鼠肺炎模型来确认高毒力表型。我们检测了来自中国三个省份的165株CRAB菌株中该基因的存在情况，并评估了携带该基因的CRAB感染与死亡率的相关性。
该基因是仅在KL49中发现的CPS合成基因。我们使用聚合酶链反应（PCR）检测该基因，从61株CRAB临床菌株中筛选出9株经WGS验证的KL49菌株。在小鼠肺炎模型中，KL49菌株的存活率显著低于非KL49菌株。LAC-4基因敲除菌株的存活率显著降低。系统发育分析显示KL49在全球范围内传播。携带该基因的CRAB感染是死亡率的独立危险因素（比值比，10.76；95%置信区间：3.08 - 37.55；P<0.001）。
KL49 CRAB的高毒力表型及其与死亡率的关联凸显了实施控制措施的迫切需求。这种快速鉴定方法有潜力促进早期医疗干预和全球监测。
