title: A potential role of  Escherichia coli  pathobionts in the pathogenesis of pediatric inflammatory bowel disease.
abstract: Through genomic analysis of mucosa-associated Escherichia coli strains, we found a close genetic association among isolates from pediatric inflammatory bowel disease (IBD) patients. A specific E. coli pathovar, adherent-invasive E. coli (AIEC), was found in Crohn's disease (CD) adult patients - this pathovar has enhanced adhesive and invasive properties, mainly due to the mannose-bonding FimH protein. We aimed to characterize 52 mucosa-associated E. coli strains isolated from pediatric IBD and non-IBD patients. Eleven E. coli strains, showing a strong similarity in fimH gene sequence to that of E. coli AIEC LF82, were characterized for fimH gene sequence, genomic profiling, adhesive and invasive ability, and phylogrouping. The results were compared with E. coli strains AIEC LF82 and MG1655. The 11 E. coli isolates showed 82.4% ± 1.4% fimH sequence similarity and 80.6% ± 1.3% genomic similarity to strain AIEC LF82. All these strains harbored V27A and S78N FimH mutations, as found in LF82. Nine of them belonged to the more virulent B2 and D phylogroups. Neuraminidase treatment, mimicking inflamed mucosa, enhanced adhesion of all 11 strains by 3.5-fold, but none showed invasion ability. It could be argued that the 11 selected strains could be a branch of an E. coli subpopulation (pathobionts), that could take advantage in an inflamed context because of a suitable genomic and (or) genetic backdrop.
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University, Microbiology Section, Piazzale Aldo Moro, 5 00185, Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Schippa
authors.forename: Valerio
authors.initials: V
authors.lastname: Iebba
authors.forename: Valentina
authors.initials: V
authors.lastname: Totino
authors.forename: Floriana
authors.initials: F
authors.lastname: Santangelo
authors.forename: Mariastefania
authors.initials: M
authors.lastname: Lepanto
authors.forename: Claudia
authors.initials: C
authors.lastname: Alessandri
authors.forename: Federica
authors.initials: F
authors.lastname: Nuti
authors.forename: Franca
authors.initials: F
authors.lastname: Viola
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Nardo
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cucchiara
authors.forename: Catia
authors.initials: C
authors.lastname: Longhi
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Conte
mesh_terms: D018830:Adhesins, Escherichia coli / Q000235:genetics / Q000378:metabolism; D000293:Adolescent; D001422:Bacterial Adhesion / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003424:Crohn Disease / Q000382:microbiology / Q000473:pathology; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000473:pathology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000382:microbiology* / Q000473:pathology; D008297:Male
chemical_list: D018830:Adhesins, Escherichia coli; D029968:Escherichia coli Proteins