Barillova Petra, Tchesnokova Veronika, Dübbers Angelika, Küster Peter, Peters Georg, Dobrindt Ulrich, Sokurenko Evgeni V, Kahl Barbara C
Medical Microbiology, University Hospital Muenster, Muenster, Germany; Department of Microbiology, University of Washington, Seattle, WA, USA.
Department of Microbiology, University of Washington, Seattle, WA, USA.
Int J Med Microbiol. 2014 May;304(3-4):415-21. doi: 10.1016/j.ijmm.2014.02.008. Epub 2014 Feb 19.
Cystic fibrosis (CF) patients suffer from chronic recurrent bacterial airway infections, which eventually lead to reduced life expectancy. Escherichia coli has not been considered as a CF pathogen. A total of 176 patients were observed over 5.6 years on average from 2002 to 2009 in two CF centers in Muenster, Germany. Sputum and throat swab cultures were screened for E. coli. E. coli isolates were analyzed for clinical microbiologic characteristics as well as strain identity, clonal distribution and phenotypic variability. In 45 patients (25.6%) E. coli was cultured at least once, mostly at medium to high bacterial load and primarily from patients less than 5 and older than 8 years. In 19 patients (10.8%) the same E. coli strain was isolated at least 3 times within a period of more than 6 months, with a mean persistence of 29 months. Multi-locus sequence typing revealed a distinctively strong association of CF E. coli with the B2 major clonal group. During persistence, long-term colonizing strains exhibited phenotypic variability known for typical CF pathogens such as surface capsule overproduction and changes in colony size or hemolytic activity. E. coli was occasionally or persistently isolated in a quarter of CF patients, mostly in very young or older patients. The relatively high bacterial load of E. coli colonization, the distinct association with the highly virulent extra-intestinal B2 clonal group and phenotypic variability in the long-term colonizing strains suggests a previously unrecognized clinical significance of E. coli as a CF pathogen.
囊性纤维化（CF）患者患有慢性复发性细菌性气道感染，最终导致预期寿命缩短。大肠杆菌一直未被视为CF病原体。2002年至2009年期间，在德国明斯特的两个CF中心，平均对176名患者进行了5.6年的观察。对痰液和咽拭子培养物进行大肠杆菌筛查。对大肠杆菌分离株进行临床微生物学特征分析，以及菌株鉴定、克隆分布和表型变异性分析。在45名患者（25.6%）中，至少有一次培养出大肠杆菌，大多数情况下细菌载量为中到高，主要来自5岁以下和8岁以上的患者。在19名患者（10.8%）中，在6个月以上的时间内至少3次分离出相同的大肠杆菌菌株，平均持续时间为29个月。多位点序列分型显示，CF大肠杆菌与B2主要克隆群有显著的强关联。在持续存在期间，长期定植菌株表现出典型CF病原体已知的表型变异性，如表面荚膜过度产生以及菌落大小或溶血活性的变化。在四分之一的CF患者中偶尔或持续分离出大肠杆菌，大多发生在非常年轻或年长的患者中。大肠杆菌定植的细菌载量相对较高、与高毒力的肠外B2克隆群有明显关联以及长期定植菌株的表型变异性表明，大肠杆菌作为CF病原体具有以前未被认识到的临床意义。
