RESUMO
Enteroaggregative Escherichia coli (EAEC) strains including those of serogroup O111 are important causes of diarrhea in children. In the Czech Republic, no information is available on the etiological role of EAEC in pediatric diarrhea due to the lack of their targeted surveillance. To fill this gap, we determined the proportion of EAEC among E. coli O111 isolates from children with gastrointestinal disorders ≤ 2 years of age submitted to the National Reference Laboratory for E. coli and Shigella during 2013-2022. EAEC accounted for 177 of 384 (46.1â¯%) E. coli O111 isolates, being the second most frequent E. coli O111 pathotype. Most of them (75.7â¯%) were typical EAEC that carried aggR, usually with aaiC and aatA marker genes; the remaining 24.3â¯% were atypical EAEC that lacked aggR but carried aaiC and/or aatA. Whole genome sequencing of 11 typical and two atypical EAEC O111 strains demonstrated differences in serotypes, sequence types (ST), virulence gene profiles, and the core genomes between these two groups. Typical EAEC O111:H21/ST40 strains resembled by their virulence profiles including the presence of the aggregative adherence fimbriae V (AAF/V)-encoding cluster to such strains from other countries and clustered with them in the core genome multilocus sequence typing (cgMLST). Atypical EAEC O111:H12/ST10 strains lacked virulence genes of typical EAEC and differed from them in cgMLST. All tested EAEC O111 strains displayed stacked-brick aggregative adherence to human intestinal epithelial cells. The AAF/V-encoding cluster was located on a plasmid of 95,749â¯bp or 93,286â¯bp (pAAO111) which also carried aggR, aap, aar, sepA, and aat cluster. EAEC O111 strains were resistant to antibiotics, in particular to aminopenicillins and cephalosporins; 88.3â¯% produced AmpC ß-lactamase, and 4.1â¯% extended spectrum ß-lactamase. We conclude that EAEC are frequent among E. coli O111 strains isolated from children with gastrointestinal disorders in the Czech Republic. To reliably assess the etiological role of EAEC in pediatric diarrhea, a serotype-independent, PCR-based pathotype surveillance system needs to be implemented in the future.
Assuntos
Diarreia , Infecções por Escherichia coli , Escherichia coli , Sequenciamento Completo do Genoma , Humanos , República Tcheca/epidemiologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/epidemiologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Escherichia coli/classificação , Lactente , Diarreia/microbiologia , Fatores de Virulência/genética , Sorogrupo , Proteínas de Escherichia coli/genética , Gastroenteropatias/microbiologia , Antibacterianos/farmacologia , Pré-Escolar , Genoma Bacteriano , Masculino , Feminino , Recém-Nascido , Tipagem de Sequências Multilocus , TransativadoresRESUMO
Non-phosphorylated lipid A species confer reduced inflammatory potential for the bacteria. Knowledge on their chemical structure and presence in bacterial pathogens may contribute to the understanding of bacterial resistance and activation of the host innate immune system. In this study, we report the fragmentation pathways of negatively charged, non-phosphorylated lipid A species under low-energy collision-induced dissociation conditions of an electrospray ionization quadrupole time-of-flight instrument. Charge-promoted consecutive and competitive eliminations of the acyl chains and cross-ring cleavages of the sugar residues were observed. The A-type fragment ion series and the complementary X-type fragment(s) with corresponding deprotonated carboxamide(s) were diagnostic for the distribution of the primary and secondary acyl residues on the non-reducing and the reducing ends, respectively, of the non-phosphorylated lipid A backbone. Reversed-phase liquid chromatography in combination with negative-ion electrospray ionization quadrupole time-of-flight tandem mass spectrometry could provide sufficient information on the primary and secondary acyl residues of a non-phosphorylated lipid A. As a standard, the hexa-acylated ion at m/z 1636 with the Escherichia coli-type acyl distribution (from E. coli O111) was used. The method was tested and refined with the analysis of other non-phosphorylated hexa- and several hepta-, penta-, and tetra-acylated lipid A species detected in crude lipid A fractions from E. coli O111 and Proteus morganii O34 bacteria. Copyright © 2016 John Wiley & Sons, Ltd.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Lipídeo A/análise , Lipídeo A/química , Espectrometria de Massas em Tandem/métodos , Escherichia coli/química , Modelos Moleculares , Fosforilação , Proteus/químicaRESUMO
We report a 14-year-old girl, who developed shigatoxin-producing E. coli (STEC)-HUS complicated by encephalopathy. She was successfully treated with hemodiafiltration, high-dose methylprednisolone pulse therapy, and soluble recombinant thrombomodulin under plasma exchange. von Willebrand factor multimers analysis provides potential insights into how the administered therapies might facilitate successful treatment of STEC-HUS.
RESUMO
The structure of the oligosaccharide repeating units of endotoxins from Gram-negative bacteria is characteristic for the different serogroups and serotypes of bacteria. Detailed examination of the cross-reactions of three enterobacterial serotypes, Proteus morganii O34, Escherichia coli O111, and Salmonella enterica sv. Adelaide O35, was performed using sensitive tests (ELISA, immunoblotting). Fine differences between the endotoxins of the bacteria were detected using silver staining of SDS-PAGE gels and chip-technology for the intact lipopolysaccharides (LPSs). The compositions of the O-specific polysaccharides of LPSs extracted from the bacteria were studied, and it was proven that the three cross-reacting bacteria contain O-antigens built from the same monosaccharides, namely colitoses linked to glucose, galactose, and N-acetyl-galactosamine. The NMR and GC-MS studies revealed that the most probable component for the cross-reaction is the rare sugar, colitose.
Assuntos
Reações Cruzadas , Enterobacteriaceae/imunologia , Configuração de Carboidratos , Eletroforese em Gel de Poliacrilamida , Cromatografia Gasosa-Espectrometria de Massas , Lipopolissacarídeos/química , Ressonância Magnética Nuclear BiomolecularRESUMO
Injection of crude lipopolysaccharide (LPS) from Escherichia coli into the hemocoel of Biomphalaria glabrata stimulates cell proliferation in the amebocyte-producing organ (APO). However, it is not known if mitogenic activity resides in the lipid A or O-polysaccharide component of LPS. Moreover, the possible role of substances that commonly contaminate crude LPS and that are known to stimulate innate immune responses in mammals, e.g., peptidoglycan (PGN), protein, or bacterial DNA, is unclear. Therefore, we tested the effects of the following injected substances on the snail APO: crude LPS, ultrapurified LPS (lacking lipoprotein contamination), two forms of lipid A, (diphosphoryl lipid A and Kdo2-lipid A), O-polysaccharide, Gram negative PGN, both crude and ultrapurified (with and without endotoxin activity, respectively), Gram positive PGN, PGN components Tri-DAP and muramyl dipeptide, and bacterial DNA. Whereas crude LPS, ultrapurified LPS, and crude PGN were mitogenic, ultrapurified PGN was not. Moreover, LPS components, PGN components, and bacterial DNA were inactive. These results suggest that it is the intact LPS molecule which stimulates cell division in the APO.