title: Prevalence and persistence of Escherichia coli in the airways of cystic fibrosis patients - an unrecognized CF pathogen?
abstract: 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.
authors.affiliation: Medical Microbiology, University Hospital Muenster, Muenster, Germany; Department of Microbiology, University of Washington, Seattle, WA, USA.
authors.forename: Petra
authors.initials: P
authors.lastname: Barillova
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA, USA.
authors.forename: Veronika
authors.initials: V
authors.lastname: Tchesnokova
authors.affiliation: Department of Pediatrics, University Hospital Muenster, Muenster, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Dübbers
authors.affiliation: Department of Pediatrics, Clemenshospital Muenster, Muenster, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Küster
authors.affiliation: Medical Microbiology, University Hospital Muenster, Muenster, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Peters
authors.affiliation: Institute of Hygiene, University Hospital Muenster, Muenster, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Dobrindt
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA, USA.
authors.forename: Evgeni V
authors.initials: EV
authors.lastname: Sokurenko
authors.affiliation: Medical Microbiology, University Hospital Muenster, Muenster, Germany. Electronic address: kahl@uni-muenster.de.
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Kahl
mesh_terms: D000293:Adolescent; D000328:Adult; D058491:Bacterial Load; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D005838:Genotype; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D010614:Pharynx / Q000382:microbiology; D015995:Prevalence; D013183:Sputum / Q000382:microbiology; D055815:Young Adult
keywords: Airways; Colonization; Cystic fibrosis; Escherichia coli; Pathoadaptation; Persistence