VI型分泌系统在引起脓肿方面的分子流行病学及临床特征
Molecular epidemiology and clinical characteristics of the type VI secretion system in causing abscesses.
作者信息
Liu Peilin, Yang Awen, Tang Bin, Wang Zhiqian, Jian Zijuan, Liu Yanjun, Wang Jiahui, Zhong Baiyun, Yan Qun, Liu Wenen
机构信息
Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China.
National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China.
出版信息
Front Microbiol. 2023 May 17;14:1181701. doi: 10.3389/fmicb.2023.1181701. eCollection 2023.
PURPOSE
The type VI system (T6SS) has the potential to be a new virulence factor for hypervirulent (hvKp) strains. This study aimed to characterize the molecular and clinical features of T6SS-positive and T6SS-negative isolates that cause abscesses.
PATIENTS AND METHODS
A total of 169 non-duplicate strains were isolated from patients with abscesses in a tertiary hospital in China from January 2018 to June 2022, and clinical data were collected. For all isolates, capsular serotypes, T6SS genes, virulence, and drug resistance genes, antimicrobial susceptibility testing, and biofilm formation assays were assessed. Multilocus sequence typing was used to analyze the genotypes of hvKp. T6SS-positive hvKp, T6SS-negative hvKp, T6SS-positive cKP, and T6SS-negative cKP ( = 4 strains for each group) were chosen for the infection model and competition experiments to further explore the microbiological characteristics of T6SS-positive isolates.
RESULTS
The positive detection rate for T6SS was 36.1%. The rates of hvKp, seven virulence genes, K1 capsular serotype, and ST23 in T6SS-positive strains were all higher than those in T6SS-negative strains ( < 0.05). Multivariate logistic regression analysis indicated that the carriage of aerobactin (OR 0.01) and (OR 33.53) were independent risk factors for T6SS-positive strains ( < 0.05). The T6SS-positive strains had a stronger biofilm-forming ability than T6SS-negative strains ( < 0.05). The T6SS-positive and T6SS-negative strains showed no significant differences in competitive ability ( = 0.06). In the infection model, the T6SS(+)/hvKP group had the worst prognosis. Except for cefazolin and tegacyclin, T6SS-positive isolates displayed a lower rate of antimicrobial resistance to other drugs ( < 0.05). The T6SS-positive isolates were more likely to be acquired from community infections ( < 0.05).
CONCLUSION
isolates causing abscesses have a high prevalence of T6SS genes. T6SS-positive isolates are associated with virulence, and the T6SS genes may be involved in the hvKp virulence mechanism.
目的
VI型分泌系统（T6SS）有可能成为高毒力肺炎克雷伯菌（hvKp）菌株的一种新的毒力因子。本研究旨在描述引起脓肿的T6SS阳性和T6SS阴性分离株的分子特征和临床特征。
患者和方法
2018年1月至2022年6月期间，在中国一家三级医院从脓肿患者中分离出169株非重复菌株，并收集临床数据。对所有分离株进行荚膜血清型、T6SS基因、毒力和耐药基因检测、抗菌药物敏感性试验以及生物膜形成测定。采用多位点序列分型分析hvKp的基因型。选择T6SS阳性hvKp、T6SS阴性hvKp、T6SS阳性cKP和T6SS阴性cKP（每组=4株）进行感染模型和竞争实验，以进一步探索T6SS阳性分离株的微生物学特征。
结果
T6SS的阳性检出率为36.1%。T6SS阳性菌株中hvKp、7种毒力基因、K1荚膜血清型和ST23的比例均高于T6SS阴性菌株（<0.05）。多因素logistic回归分析表明，气杆菌素携带（OR 0.01）和（OR 33.53）是T6SS阳性菌株的独立危险因素（<0.05）。T6SS阳性菌株比T6SS阴性菌株具有更强的生物膜形成能力（<0.05）。T6SS阳性和T6SS阴性菌株在竞争能力方面无显著差异（=0.06）。在感染模型中，T6SS(+)/hvKP组预后最差。除头孢唑林和替加环素外，T6SS阳性分离株对其他药物的耐药率较低（<0.05）。T6SS阳性分离株更可能来自社区感染（<0.05）。
结论
引起脓肿的分离株中T6SS基因的患病率较高。T6SS阳性分离株与毒力相关，T6SS基因可能参与hvKp的毒力机制。
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