title: Multi-Typing of Enterobacteria Harboring LT and ST Enterotoxin Genes Isolated from Mexican Children.
abstract: Enterotoxigenic Escherichia coli is the most common cause of diarrhea in children younger than 5 years in the developing world. We used 16S rRNA gene sequencing, the Biolog®system, and an Amplified Ribosomal DNA Restriction Analysis (ARDRA) to identify 69 enterobacteria isolated from the feces of healthy children up to 12 years old and 54 enterobacteria isolated from stool samples obtained from children up to 5 years old with diarrhea from Morelia, Michoacán, Mexico. In the diarrheic group, 18 isolates belonged to the enterotoxigenic pathotype, 1 isolate had both LT (heat labile toxin) gene and ST (heat stable toxin) gene, and 17 had the ST gene. The identity of most of the strains harboring the ST gene was E. coli, and 3 of the strains were identified as Morganella morganii. The ST toxin gene of one of the strains identified as M. morganii showed 100% identity with an ST toxin gene of E. coli. The ARDRA was a very useful tool to differentiate between E. coli and M. morganii. The phenotypic and genetic analyses of the isolates using the Biolog®system and Random Amplified Polymorphic DNA, respectively, showed physiological variation among the studied strains and genetic differences between subgroups.
authors.affiliation: Multidisciplinary Center for Studies in Biotechnology, Faculty of Veterinary Medicine, Michoacán University of San Nicolás of Hidalgo.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Vázquez-Marrufo
authors.forename: Jesús Andrei
authors.initials: JA
authors.lastname: Rosales-Castillo
authors.forename: Virginia A
authors.initials: VA
authors.lastname: Robinson-Fuentes
authors.forename: Iliana
authors.initials: I
authors.lastname: Tafolla-Muñoz
authors.forename: Nohemí
authors.initials: N
authors.lastname: Carreras-Villaseñor
authors.forename: Ma Soledad
authors.initials: MS
authors.lastname: Vázquez-Garcidueñas
mesh_terms: D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology*; D004768:Enterotoxins / Q000145:classification / Q000235:genetics*; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007223:Infant; D008297:Male; D008800:Mexico; D058889:Molecular Typing; D020613:Morganella morganii / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D004768:Enterotoxins; D012336:RNA, Ribosomal, 16S