中国西部一家三级教学医院中携带bla和iucA的ST11-KL64碳青霉烯耐药高毒力肺炎克雷伯菌分离株的出现。

Emergence of ST11-KL64 carbapenem-resistant hypervirulent Klebsiella Pneumoniae isolates harboring bla and iucA from a tertiary teaching hospital in Western China.

作者信息

Chen Haojun, Li Tingting, Huang Xiaoxue, He Qiurong

机构信息

Department of Laboratory Medicine, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, 610041, China.

Department of Laboratory Medicine, West China Lecheng Hospital, Sichuan University, Qionghai, 571421, China.

出版信息

BMC Infect Dis. 2025 Jul 1;25(1):880. doi: 10.1186/s12879-025-11241-6.

DOI:10.1186/s12879-025-11241-6

PMID:40596916

Abstract

BACKGROUND

Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-HvKP) poses a critical global health threat. However, molecular epidemiological data on CR-HvKP in Western China remain scarce. This study aimed to characterize the clinical profiles, molecular features, and risk factors of CR-HvKP isolates in Western China.

METHODS

Sixty-eight carbapenem-resistant Klebsiella pneumoniae (CRKP) clinical isolates were collected from January to December in 2024. Clinical characterization included antimicrobial susceptibility profiling and hypermucoviscosity assessment via string test. Detection of carbapenemases using inhibitor enhancement test. Molecular characteristics of CRKP included serotype, carbapenemases, virulence-associated factors, and multilocus sequence typing (MLST) performed by using the PCR method. CR-HvKP was defined as the presence of any one of rmpA, rmpA2, iroB, iucA, and peg-344. Risk factors were initially evaluated using univariate logistic regression analysis, with significant variables subsequently incorporated into a multivariate regression model. A p-value < 0.05 was considered statistically significant.

RESULTS

Among 68 CRKP isolates, 36 were identified as CR-HvKP, all harboring the iucA gene (100%, 36/36). However, only 22.2% (8/36) of string test results correlated with virulence gene presence. All CRKP strains exhibited high resistance to most antibiotics, with comparatively lower resistance rates observed for tigecycline (0%) and polymyxin B (14.7%). Carbapenemase production was the predominant resistance mechanism, with 61.8% (42/68) carrying bla. Serotyping and MLST revealed that ST11-KL64 CR-HvKP being predominant. A novel wzi752 allele was identified, encoding amino acid sequences homologous to serotype KL47. Univariate analysis demonstrated significantly higher ICU admission rates (p = 0.018) and carbapenem exposure (p = 0.023) in CR-HvKP patients with infections. Multivariate analysis highlighted borderline significance for ICU admission (OR = 2.939, p = 0.056) as a potential risk factor.

CONCLUSIONS

The ST11-KL64 CR-HvKP clone harboring bla and iucA has emerged as a dominant pathogen of hospital infections in Western China, posing dual threats of resistance and virulence. Enhanced molecular surveillance and infection control strategies are urgently needed to mitigate its spread.

摘要

背景

耐碳青霉烯类高毒力肺炎克雷伯菌（CR-HvKP）对全球健康构成严重威胁。然而，中国西部关于CR-HvKP的分子流行病学数据仍然匮乏。本研究旨在描述中国西部CR-HvKP分离株的临床特征、分子特征和危险因素。

方法

2024年1月至12月收集了68株耐碳青霉烯类肺炎克雷伯菌（CRKP）临床分离株。临床特征包括抗菌药物敏感性分析和通过悬滴试验进行的高黏液性评估。使用抑制剂增强试验检测碳青霉烯酶。CRKP的分子特征包括血清型、碳青霉烯酶、毒力相关因子以及采用聚合酶链反应（PCR）方法进行的多位点序列分型（MLST）。CR-HvKP被定义为存在rmpA、rmpA2、iroB、iucA和peg-344中的任何一种。危险因素最初使用单因素逻辑回归分析进行评估，随后将显著变量纳入多因素回归模型。p值<0.05被认为具有统计学意义。

结果

在68株CRKP分离株中，36株被鉴定为CR-HvKP，均携带iucA基因（100%，36/36）。然而，只有22.2%（8/36）的悬滴试验结果与毒力基因的存在相关。所有CRKP菌株对大多数抗生素均表现出高度耐药，对替加环素（0%）和多黏菌素B（14.7%）的耐药率相对较低。碳青霉烯酶产生是主要的耐药机制，61.8%（42/68）携带bla。血清型和MLST显示ST11-KL64 CR-HvKP占主导地位。鉴定出一个新的wzi752等位基因，其编码的氨基酸序列与血清型KL47同源。单因素分析表明，CR-HvKP感染患者的ICU入住率（p = 0.018）和碳青霉烯类药物暴露（p = 0.023）显著更高。多因素分析突出了ICU入住（OR = 2.939，p = 0.056）作为潜在危险因素的临界显著性。