title: Identification of two new intimin types in atypical enteropathogenic Escherichia coli.
abstract: Stool specimens of patients with diarrhea or other gastrointestinal alterations who were admitted to Xeral-Calde Hospital (Lugo, Spain) were analyzed for the prevalence of typical and atypical enteropathogenic Escherichia coli (EPEC). Atypical EPEC strains (eae+ bfp-) were detected in 105 (5.2%) of 2015 patients, whereas typical EPEC strains (eae+ bfp+) were identified in only five (0.2%) patients. Atypical EPEC strains were (after Salmonella) the second most frequently recovered enteropathogenic bacteria. In this study, 110 EPEC strains were characterized. The strains belonged to 43 O serogroups and 69 O:H serotypes, including 44 new serotypes not previously reported among human EPEC. However, 29% were of one of three serogroups (O26, O51, and O145) and 33% belonged to eight serotypes (O10:H-, O26:H11, O26:H-, O51:H49, O123:H19, O128:H2, O145:H28, and O145:H-). Only 14 (13%) could be assigned to classical EPEC serotypes. Fifteen intimin types, namely, alpha1 (6 strains), alpha2 (4 strains), beta1 (34 strains), xiR/b2 (6 strains), gamma1 (13 strains), gamma2/q (16 strains), delta/k (5 strains), epsilon1 (9 strains), nuR/e2 (5 strains), zeta (6 strains), iota1 (1 strain), muR/iota2 (1 strain), nuB (1 strain), xiB (1 strain), and o (2 strains), were detected among the 110 EPEC strains, but none of the strains was positive for intimin types mu1, mu2, lambda, or muB. In addition, in atypical EPEC strains of serotypes O10:H-, O84:H-, and O129:H-, two new intimin genes (eae-nuB and eae-o) were identified. These genes showed less than 95% nucleotide sequence identity with existing intimin types. Phylogenetic analysis revealed six groups of closely related intimin genes: (i) alpha1, alpha2, zeta, nuB, and o; (ii) iota1 and muR/iota2; (iii) beta1, xiR/beta2B, delta/beta2O, and kappa; (iv) epsilon1, xiB, eta1,eta2, and nuR/epsilon2; (v) gamma1, muB, gamma2, and theta; and (vi) lambda. These results indicate that atypical EPEC strains belonging to large number of serotypes and with different intimin types might be frequently isolated from human clinical stool samples in Spain.
authors.affiliation: E. coli Reference Laboratory (LREC), Department of Microbiology and Parasitology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Blanco
authors.forename: Jesús E
authors.initials: JE
authors.lastname: Blanco
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: María P
authors.initials: MP
authors.lastname: Alonso
authors.forename: Azucena
authors.initials: A
authors.lastname: Mora
authors.forename: Maria A
authors.initials: MA
authors.lastname: Coira
authors.forename: Cristina
authors.initials: C
authors.lastname: Madrid
authors.forename: Antonio
authors.initials: A
authors.lastname: Juárez
authors.forename: María I
authors.initials: MI
authors.lastname: Bernárdez
authors.forename: Enrique A
authors.initials: EA
authors.lastname: González
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D006801:Humans; D010802:Phylogeny; D012703:Serotyping; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli