产酸克雷伯菌 pks 基因簇的流行情况及克雷伯菌属引起的血流感染的特征。
Prevalence of pks gene cluster and characteristics of Klebsiella pneumoniae-induced bloodstream infections.
机构信息
Department of Clinical Laboratory, Xiangya Hospital Central South University, Changsha, China.
出版信息
J Clin Lab Anal. 2019 May;33(4):e22838. doi: 10.1002/jcla.22838. Epub 2019 Feb 8.
BACKGROUND
The emerging pks-positive (pks ) strains have aroused great public concern recently. Colibactin, encoded by pks gene cluster, has been reported to be involved in DNA damage and increased virulence. Little is known about its prevalence among Klebsiella pneumoniae-induced bloodstream infections (BSIs). Therefore, the aim of this study was to investigate the prevalence of pks gene cluster, and molecular and clinical characteristics of K pneumoniae-induced BSIs.
METHODS
A total of 190 non-duplicate K pneumoniae bloodstream isolates were collected at a university hospital in China from March 2016 to March 2018. Molecular characteristics including capsular types, virulence, and pks genes were detected by polymerase chain reaction (PCR). Clinical characteristics and antimicrobial susceptibility were also investigated.
RESULTS
Overall, 21.6% (41/190) of K pneumoniae bloodstream isolates were hypervirulent K pneumoniae(hvKP). The prevalence of pks gene cluster was 26.8% (51/190). The positive rates of K1, K57, and genes associated with hypervirulence, that is, rmpA, wcaG, mrkD, allS, ybtS, kfu,and iucA, were significantly higher in the pks isolates than the pks-negative (pks ) isolates (P < 0.05), while the pks isolates were significantly less resistant to 11 antimicrobial agents than the pks isolates. Multivariate analysis showed diabetes mellitus, and K1 and K20 capsular types as independent risk factors for pks K pneumoniaebloodstream infections.
CONCLUSIONS
The pks K pneumoniae was prevalent in individuals with bloodstream infections in mainland China. The high rates of hypervirulent determinants among pks K pneumoniaerevealed the potential pathogenicity of this emerging gene cluster. Diabetes mellitus, and K1 and K20 capsular types were identified as independent risk factors associated with pks K pneumoniaebloodstream infections. This study highlights the significance of clinical awareness and epidemic surveillance of pks strains.
背景
最近，新兴的 pks 阳性（pks）菌株引起了公众的极大关注。pks 基因簇编码的 colibactin 已被报道参与 DNA 损伤和增加毒力。关于肺炎克雷伯菌引起的血流感染（BSI）中 pks 基因簇的流行情况知之甚少。因此，本研究旨在调查 pks 基因簇的流行情况，以及肺炎克雷伯菌引起的 BSI 的分子和临床特征。
方法
本研究共收集了 2016 年 3 月至 2018 年 3 月期间在中国一所大学医院的 190 例非重复肺炎克雷伯菌血流分离株。通过聚合酶链反应（PCR）检测分子特征，包括荚膜型、毒力和 pks 基因。还调查了临床特征和抗菌药物敏感性。
结果
总体而言，21.6%（41/190）的肺炎克雷伯菌血流分离株为高毒力肺炎克雷伯菌（hvKP）。pks 基因簇的阳性率为 26.8%（51/190）。与 pks 阴性（pks）分离株相比，pks 分离株的 K1、K57 和与高毒力相关的基因，即 rmpA、wcaG、mrkD、allS、ybtS、kfu 和 iucA 的阳性率显著更高（P<0.05），而 pks 分离株对 11 种抗菌药物的耐药率显著低于 pks 分离株。多变量分析显示，糖尿病、K1 和 K20 荚膜型是 pks 肺炎克雷伯菌血流感染的独立危险因素。
结论
在中国大陆，pks 肺炎克雷伯菌在血流感染患者中较为常见。pks 肺炎克雷伯菌中高比例的高毒力决定因子表明该新兴基因簇具有潜在的致病性。糖尿病、K1 和 K20 荚膜型被确定为与 pks 肺炎克雷伯菌血流感染相关的独立危险因素。本研究强调了对 pks 菌株的临床认识和流行监测的重要性。
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