1Huntington Hospital, Pasadena, CA. 2University of Southern California, Los Angeles, CA.
Crit Care Med. 2014 Jan;42(1):48-56. doi: 10.1097/CCM.0b013e318298a86f.
To determine the differential association of host characteristics, antimicrobial resistance, and type III secretion system virulence of Pseudomonas aeruginosa isolates with respiratory syndromes in hospitalized adult patients.
Retrospective, cohort study.
Community teaching hospital.
Two hundred eighteen consecutive adult patients with respiratory culture positive for P. aeruginosa between January 2005 to January 2010.
Medical charts were reviewed to obtain demographic, laboratory, radiographic, and clinical information. Isolates were assayed by polymerase chain reaction for genes encoding the type III secretion system effectors (ExoU, ExoS, and PcrV) and for strain relatedness using randomly amplified polymorphic DNA analysis. Levofloxacin susceptibility was determined by broth microdilution. Patients were grouped by colonization, bronchitis, or pneumonia and were compared for differential risk of developing the clinical syndrome with respect to host and microbial characteristics.
Half of the study cohort (54%, 117 of 218) had pneumonia, 32% (70 of 218) had bronchitis, and 14% (31 of 218) had colonization; in-hospital mortality was 35%, 11%, and 0%, respectively. Host factors strongly associated with pneumonia development were residence in long-term care facility, healthcare-associated acquisition of P. aeruginosa, higher Acute Physiology and Chronic Health Evaluation II score, presence of enteral feeding tube, mechanical ventilation, and recent history of pneumonia. Fluoroquinolone-resistant (57% vs 34%, 16%; p < 0.0001) and multidrug-resistant (36% vs 26%, 7%; p = 0.0045) strains were more likely to cause pneumonia than bronchitis or colonization, respectively. Analysis of host and microbial factors in a multivariate regression model yielded the combined traits of fluoroquinolone resistance and gene encoding the type III secretion system ExoU effector in P. aeruginosa as the single most significant predictor of pneumonia development.
These results suggest that fluoroquinolone-resistant phenotype in a type III secretion system exoU strain background contributes toward the pathogenesis of P. aeruginosa in pneumonia.
确定宿主特征、抗菌药物耐药性和铜绿假单胞菌分离株 III 型分泌系统毒力与住院成年患者呼吸道综合征的差异关联。
回顾性队列研究。
社区教学医院。
2005 年 1 月至 2010 年 1 月间，连续 218 例呼吸道培养阳性的成年患者。
查阅病历以获取人口统计学、实验室、影像学和临床信息。通过聚合酶链反应检测分离株 III 型分泌系统效应物（ExoU、ExoS 和 PcrV）编码基因，并通过随机扩增多态性 DNA 分析检测菌株相关性。通过肉汤微量稀释法确定左氧氟沙星敏感性。根据定植、支气管炎或肺炎将患者分组，并比较宿主和微生物特征对临床综合征的不同发病风险。
研究队列的一半（54%，117/218）患有肺炎，32%（70/218）患有支气管炎，14%（31/218）患有定植；住院死亡率分别为 35%、11%和 0%。与肺炎发展密切相关的宿主因素包括居住在长期护理机构、获得与卫生保健相关的铜绿假单胞菌、较高的急性生理学和慢性健康评估 II 评分、肠内喂养管、机械通气和近期肺炎史。氟喹诺酮耐药（57%比 34%，16%；p<0.0001）和多重耐药（36%比 26%，7%；p=0.0045）菌株引起肺炎的可能性分别高于支气管炎或定植。多变量回归模型中对宿主和微生物因素的分析得出，铜绿假单胞菌中氟喹诺酮耐药和 III 型分泌系统 ExoU 效应物编码基因的组合特征是肺炎发生的唯一最重要预测因子。
这些结果表明，III 型分泌系统 ExoU 菌株背景下的氟喹诺酮耐药表型有助于铜绿假单胞菌在肺炎中的发病机制。
