Zhuo Xianxia, Lei Zichen, Pu Danni, Wu Yongli, Zhao Jiankang, Cao Bin
Department of Respiratory Medicine, Capital Medical University, Beijing, China.
National Center for Respiratory Medicine; State Key Laboratory of Respiratory Health and Multimorbidity; National Clinical Research Center for Respiratory Diseases; Institute of Respiratory Medicine, Chinese Academy of Medical Sciences; Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, No. 2 East Yinghua Street, Chaoyang District, Beijing, 100029, China.
BMC Microbiol. 2025 Jan 22;25(1):40. doi: 10.1186/s12866-024-03726-2.
The clinical outcomes and microbiological features of lower respiratory tract infections (LRTIs) caused by hypervirulent Klebsiella pneumoniae (hvKp) and classical Klebsiella pneumoniae (cKp) have not been well understood.
This study collected 287 non-repetitive Klebsiella pneumoniae isolates from 287 LRTI patients. All these strains underwent annotation for resistance and virulence factors, with 141 strains undergoing mouse infection experiments to assess their virulence. The primary clinical outcomes of these patients were evaluated, including intensive care unit (ICU) admission and in-hospital mortality rates.
A total of 46 capsule serotypes were identified. Among these isolates subjected to mouse infection experiments, the proportions of strains exhibiting hypervirulent phenotypes were 92.6% (25/27), 92.1% (35/38), 80% (4/5), 25% (1/4), 10.5% (2/19), and 7.1% (1/14) for K2, K1, K20, K54, K47, and K25, respectively. Therefore, K1, K2, and K20 K. pneumoniae were defined as hvKp. In addition, the rates of ICU admission and in-hospital mortality for hvKp-infected patients were significantly lower than those of cKp-infected patients (51.4% vs. 65.9%, χ2 = 4.722, p = 0.03 and 8.6% vs. 29%, χ2 = 12.133, p < 0.001). Notably, among the cKp group, the cKp-ST11 subgroup had higher rates of ICU admission (77% vs. 58.5%, χ2 = 7.981, p = 0.005) and in-hospital mortality (44.8% vs. 18.5%, χ2 = 17.585, p < 0.001) than cKp-nonST11 subgroup.
These findings suggest that capsule serotype is a more accurate factor for the prediction of the virulence phenotype, while hvKp have better clinical outcomes than cKp for LRTI patients. Furthermore, the cKp-ST11 subgroup has the worst prognosis than cKp-nonST11 subgroup.
高毒力肺炎克雷伯菌（hvKp）和经典肺炎克雷伯菌（cKp）引起的下呼吸道感染（LRTIs）的临床结局和微生物学特征尚未得到充分了解。
本研究收集了287例LRTI患者的287株非重复肺炎克雷伯菌分离株。所有这些菌株均进行了耐药性和毒力因子注释，其中141株进行了小鼠感染实验以评估其毒力。评估了这些患者的主要临床结局，包括重症监护病房（ICU）入院率和住院死亡率。
共鉴定出46种荚膜血清型。在这些进行小鼠感染实验的分离株中，K2、K1、K20、K54、K47和K25表现出高毒力表型的菌株比例分别为92.6%（25/27）、92.1%（35/38）、80%（4/5）、25%（1/4）、10.5%（2/19）和7.1%（1/14）。因此，K1、K2和K20型肺炎克雷伯菌被定义为hvKp。此外，hvKp感染患者的ICU入院率和住院死亡率显著低于cKp感染患者（51.4%对65.9%，χ2 = 4.722，p = 0.03；8.6%对29%，χ2 = 12.133，p < 0.001）。值得注意的是，在cKp组中，cKp-ST11亚组的ICU入院率（77%对58.5%，χ2 = 7.981，p = 0.005）和住院死亡率（44.8%对18.5%，χ2 = 17.585，p < 0.001）高于cKp-nonST11亚组。
这些发现表明，荚膜血清型是预测毒力表型更准确的因素，而对于LRTI患者，hvKp的临床结局优于cKp。此外，cKp-ST11亚组的预后比cKp-nonST11亚组更差。
