title: Molecular analysis of subtilase cytotoxin genes of food-borne Shiga toxin-producing Escherichia coli reveals a new allelic subAB variant.
abstract: BACKGROUND
  The open reading frames of subAB genes and their flanking regions of 18 food-borne Shiga toxin-producing E. coli (STEC) strains were analyzed.
  
  
  RESULTS
  All but one subAB open reading frames (ORF) were complete in all STEC strains. The subAB1 genes of nine STEC strains were located on large plasmids. The subAB2 allele (here designated subAB2-1), which was recently described by others to be present in the Subtilase-Encoding PAI (SE-PAI) was found in 6 STEC strains. A new chromosomal subAB2 variant, designated subAB2-2 was detected in 6 strains and was linked to a chromosomal gene hypothetically encoding an outer membrane efflux protein (OEP). Three STEC strains contained both subAB2 variants. DNA analysis indicated sequence conservation in the plasmid-located alleles and sequence heterogeneity among the chromosomal subAB2 genes.
  
  
  CONCLUSIONS
  The results of this study have shown that 18 subAB-PCR positive STEC strains contain complete subAB open reading frames. Furthermore, the new allelic variant subAB2-2 was described, which can occur in addition to subAB2-1 on a new chromosomal locus.
authors.forename: Joschua
authors.initials: J
authors.lastname: Funk
authors.forename: Helen
authors.initials: H
authors.lastname: Stoeber
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Hauser
authors.affiliation: Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 28, Stuttgart, D-70599, Germany. herbert.schmidt@uni-hohenheim.de.
authors.forename: Herbert
authors.initials: H
authors.lastname: Schmidt
mesh_terms: D000483:Alleles; D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics*; D005516:Food Microbiology; D056426:Genetic Loci; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D017422:Sequence Analysis, DNA; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics* / Q000302:isolation & purification*; D013381:Subtilisins / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D013381:Subtilisins; C527234:subtilase cytotoxin, E coli