8 results on '"Scaletsky ICA"'
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2. Escherichia coli infections and malnutrition.
- Author
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Neto UF and Scaletsky ICA
- Published
- 2000
- Full Text
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3. Transposon mutagenesis of atypical enteroaggregative Escherichia coli reveals a hemagglutinin-associated protein that mediates cell adhesion and contributes to the Galleria mellonella virulence.
- Author
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Monfardini MV, Souza RT, Rojas TCG, Guerrieri CG, Orikaza C, and Scaletsky ICA
- Subjects
- Humans, Escherichia coli metabolism, Hemagglutinins metabolism, HeLa Cells, Virulence genetics, Cell Adhesion, Bacterial Adhesion genetics, Mutagenesis, Escherichia coli Proteins genetics, Escherichia coli Proteins metabolism, Escherichia coli Infections genetics
- Abstract
Twenty-two atypical enteroaggregative Escherichia coli isolates from a previous epidemiological study harboring EAEC virulence genes were examined for their adhesion properties. Nine strains showed a typical aggregative adherence (AA) pattern, while 13 strains showed variant AA, such as AA with lined up cells characteristic of the chain-like adhesion (CLA) and AA mainly to HeLa cells characteristic of the diffuse adherence (DA). The aggregative forming pilus (AFP) genes afpA2 and afpR were detected only in strain Q015B, which exhibited an AA/DA pattern. Using Tn5-based transposon mutagenesis on Q015B strain, we identified a 5517-bp open reading frame (ORF) encoding a predicted 1838-amino-acid polypeptide that is genetically related to a putative filamentous hemagglutinin identified in E. coli strain 7-233-03_S3_C2. Therefore, the ORF was named orfHA . The regions flanking orfHA were sequenced and two ORFs were found; upstream, an ORF that encodes a 603-amino-acid polypeptide with 99% identity to hemolysin secretion/activation proteins of the ShlB/FhaC/HecB family, and downstream, another ORF, which encodes a 632-amino-acid polypeptide with 72% identity to the glycosyltransferase EtpC. An orfHA mutant (Q015BΔ orfHA ) was constructed from strain Q015B. Q015BΔ orfHA strain did not adhere to HeLa cells, whereas Q015BΔ orfHA transformed with a pACYC184 plasmid carrying orfHA restored the AA/DA phenotype of strain Q015B. Furthermore, the Q015Δ orfHA mutant had a marked effect on the ability of strain Q015B to kill the larvae of Galleria mellonella . Our results suggest that the AA/DA pattern of strain Q015B is mediated by a hemagglutinin-associated protein which also contributes to its virulence in the G. mellonella model., Competing Interests: The authors declare that the study was conducted in the absence of commercial or financial relationships that could be interpreted as potential conflicts of interest., (Copyright © 2023 Monfardini, Souza, Rojas, Guerrieri, Orikaza and Scaletsky.)
- Published
- 2023
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- View/download PDF
4. Large plasmids encoding antibiotic resistance and localized-like adherence in atypical enteropathogenic Escherichia coli strains.
- Author
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Silva SS, Monfardini MV, and Scaletsky ICA
- Subjects
- Ampicillin pharmacology, Bacterial Adhesion, Conjugation, Genetic, Enteropathogenic Escherichia coli drug effects, Enteropathogenic Escherichia coli isolation & purification, Fimbriae Proteins genetics, Gene Transfer, Horizontal, HeLa Cells, Humans, Kanamycin pharmacology, Microbial Sensitivity Tests, Mutagenesis, Insertional, Tetracycline pharmacology, Anti-Bacterial Agents pharmacology, Drug Resistance, Bacterial, Enteropathogenic Escherichia coli genetics, Escherichia coli Proteins genetics, Plasmids genetics
- Abstract
Background: In previous studies, we have shown that atypical enteropathogenic Escherichia coli (aEPEC) strains are important diarrheal pathogens among Brazilian children. In the characterization of a collection of 126 aEPEC strains, we identified 29 strains expressing the localized-like adherence (LAL) pattern on HEp-2 cells and harboring large plasmids in the range of 60 to 98 MDa. In this study, we examined 18 of these strains for their ability to transfer the LAL phenotype to a E. coli K-12 C600 strain., Results: In conjugation experiments, using eight strains which were resistant to one or more antimicrobials and positive for F-pili genes (traA), we were able to cotransfer antimicrobial resistance markers along with adhesion genes. By transforming E. coli DH5α with plasmid DNA from strains A46 (pIS46), A66 (pIS66) and A102 (pIS102), we were able to demonstrate that genes encoding ampicillin, tetracycline and LAL were encoded on a 98-MDa conjugative plasmid. To identify a gene responsible for LAL, we constructed a transposon mutant library of A102 strain. Among 18 mutants that did not adhere to HeLa cells, four carried insertions within fimbrial genes (fimA and traJ) and agglutinin genes (tia and hek). Using these Tn5 mutants as donors, we were able to obtain kanamycin-resistant E. coli MA3456 transconjugants. Sequence analysis of the plasmid genes revealed a region exhibit to 80 and 73% amino acid similarities to the agglutinins Tia and Hek, respectively., Conclusion: In this study, we have identified three large conjugative plasmids, pIS46, pIS66 and pIS102, coding for antimicrobial resistance and localized-like adherence (LAL) to HeLa cells. In addition, we identified a tia/hek homolog encoded on the pIS102 plasmid, which seems to be involved in adhesion of A102 strain.
- Published
- 2020
- Full Text
- View/download PDF
5. High prevalence of diarrheagenic Escherichia coli carrying toxin-encoding genes isolated from children and adults in southeastern Brazil.
- Author
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Spano LC, da Cunha KF, Monfardini MV, de Cássia Bergamaschi Fonseca R, and Scaletsky ICA
- Subjects
- Adolescent, Adult, Animals, Bacterial Toxins metabolism, Brazil epidemiology, Child, Child, Preschool, Diarrhea epidemiology, Enteropathogenic Escherichia coli classification, Enteropathogenic Escherichia coli genetics, Escherichia coli Infections epidemiology, Escherichia coli Proteins genetics, Escherichia coli Proteins metabolism, Female, Humans, Male, Multiplex Polymerase Chain Reaction, Prevalence, Swine, Swine Diseases epidemiology, Swine Diseases microbiology, Virulence Factors genetics, Virulence Factors metabolism, Young Adult, Diarrhea microbiology, Enteropathogenic Escherichia coli isolation & purification, Escherichia coli Infections microbiology
- Abstract
Background: Diarrheagenic Escherichia coli (DEC) are important bacterial causes of childhood diarrhea in Brazil, but its impact in adults is unknown. This study aimed at investigating DEC among children and adults living in endemic areas., Methods: A total of 327 stools specimens were collected from children (n = 141) and adults (n = 186) with diarrhea attending health centers. Diarrheagenic E. coli (DEC) were identified by their virulence genes (multiplex polymerase chain reaction) and HEp-2 cell adherence patterns., Results: DEC were detected in 56 (40%) children and 74 (39%) adults; enteroaggregative E. coli (EAEC) (23%) was the most prevalent pathotype, followed by diffusely adherent E. coli (DAEC) (13%), and occurred at similar frequencies in both diarrheal groups. Atypical enteropathogenic E. coli (aEPEC) strains were recovered more frequently from children (6%) than from adults (1%). Twenty-six percent of the EAEC were classified as typical EAEC possessing aggR gene, and carried the aap gene. EAEC strains carrying aggR-aap-aatA genes were significantly more frequent among children than adults (p < 0.05). DAEC strains possessing Afa/Dr. genes were detected from children (10%) and adults (6%). EAEC and DAEC strains harboring genes for the EAST1 (astA), Pet, Pic, and Sat toxins were common in both diarrheal groups. The astA and the porcine AE/associated adhesin (paa) genes were found in most of aEPEC strains. High levels of resistance to antimicrobial drugs were found among DAEC and aEPEC isolates., Conclusion: The results show a high proportion of EAEC and DAEC carrying toxin-encoding genes among adults with diarrhea.
- Published
- 2017
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- View/download PDF
6. Variants of astA gene among extra-intestinal Escherichia coli of human and avian origin.
- Author
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Maluta RP, Leite JL, Rojas TCG, Scaletsky ICA, Guastalli EAL, Ramos MC, and Dias da Silveira W
- Subjects
- Amino Acid Sequence, Animals, Bacterial Toxins chemistry, Base Sequence, Enterotoxins chemistry, Escherichia coli classification, Escherichia coli Proteins chemistry, Genes, Bacterial, Humans, Models, Molecular, Protein Conformation, Sequence Analysis, DNA, Serogroup, Virulence genetics, Bacterial Toxins genetics, Enterotoxins genetics, Escherichia coli genetics, Escherichia coli Proteins genetics, Genetic Variation
- Abstract
Many Escherichia coli strains harbour astA, which is the gene encoding the enteroaggregative E. coli heat-stable enterotoxin (EAST1). This gene is embedded in a putative transposase (ORF1) and presents polymorphism in diarrheagenic strains. Although astA and orf1 are detected in extraintestinal strains, little is known about polymorphism and differential gene transcription in this pathotype. In the present work, extraintestinal E. coli from humans (ExPEC - Extraintestinal Pathogenic E. coli) and poultry (APEC - Avian Pathogenic E. coli) were assayed to verify the presence of astA/orf1 and possible polymorphisms in these genes. Three astA/orf1 patterns were detected via Sanger sequencing. Pattern 1 was novel and represented an astA pseudogene. Pattern 2 and pattern 3 presented distinct amino acids within the reading frame encoding astA and were identical to the sequences found in EAEC 17-2 and EAEC 042, respectively. Regarding the frame encoding ORF1, all mutations detected in the three patterns were neutral. The transcripts of astA/orf1 in vitro were underregulated in strains possessing the pattern 1 sequence. The results demonstrate that the same astA sequences may be detected in diarrheagenic and extra-intestinal E. coli. However, extraintestinal isolates may also present an astA pseudogene that has not been reported in diarrheagenic E. coli., (© FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2017
- Full Text
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7. Age-specific prevalence of diffusely adherent Escherichia coli in Brazilian children with acute diarrhoea.
- Author
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Spano LC, Sadovsky ADI, Segui PN, Saick KW, Kitagawa SMS, Pereira FEL, Fagundes-Neto U, and Scaletsky ICA
- Subjects
- Acute Disease, Age Distribution, Brazil epidemiology, Child, Preschool, DNA, Bacterial analysis, DNA, Bacterial isolation & purification, Diarrhea microbiology, Escherichia coli classification, Escherichia coli Infections microbiology, Feces, Humans, Infant, Infant, Newborn, Nucleic Acid Hybridization methods, Prevalence, Diarrhea epidemiology, Escherichia coli genetics, Escherichia coli isolation & purification, Escherichia coli Infections epidemiology
- Abstract
In a prospective study between February 2003 and June 2004, stool specimens of children less than 2 years of age with diarrhoea (n=218) and without diarrhoea (n=86), living in Vitória, Espírito Santo, Brazil, were examined for the presence of diarrhoeagenic Escherichia coli. E. coli isolates were tested by colony blot hybridization with specific DNA probes designed to detect EPEC, ETEC, EIEC, EAEC, DAEC and EHEC/STEC. Diarrhoeagenic E. coli strains were detected as the sole pathogen in stools of 92 (30.3 %) children, including 72 (33.0 %) with diarrhoea and 20 (23.2 %) without diarrhoea. DAEC was the most frequent pathotype and was found significantly more often from patients (18.3 %) than from controls (8.1 %) (P<0.05), particularly among children more than 1 year of age (P=0.01). Atypical EPEC and EAEC isolates were isolated from both patients (5.5 % and 4.6 %, respectively) and controls (6.9 % and 6.9 %, respectively). ETEC was more frequently isolated from patients (3.2 %) than controls (1.2 %). Typical EPEC (0.9 %) and EIEC (0.4 %) isolates were detected only in children with diarrhoea. In conclusion, our data suggest that DAEC should be considered potential pathogens in the region of Brazil studied.
- Published
- 2008
- Full Text
- View/download PDF
8. Virulence properties of atypical EPEC strains.
- Author
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Pelayo JS, Scaletsky ICA, Pedroso MZ, Sperandio V, Girón JA, Frankel G, and Trabulsi LR
- Subjects
- Actins metabolism, Animals, Bacterial Outer Membrane Proteins classification, Bacterial Outer Membrane Proteins genetics, Bacterial Outer Membrane Proteins immunology, Bacterial Outer Membrane Proteins metabolism, Bacterial Toxins biosynthesis, Cell Line, Cytotoxins biosynthesis, Escherichia coli drug effects, Escherichia coli metabolism, Escherichia coli ultrastructure, Genes, Bacterial genetics, Gentamicins pharmacology, Hemolysin Proteins genetics, Hemolysin Proteins metabolism, Hemolysis, Humans, Immune Sera pharmacology, Microscopy, Electron, Rabbits, Virulence physiology, Adhesins, Bacterial, Bacterial Adhesion drug effects, Carrier Proteins, Diarrhea microbiology, Escherichia coli pathogenicity, Escherichia coli Infections microbiology, Escherichia coli Proteins
- Abstract
Virulence properties of 31 atypical enteropathogenic Escherichia coli (EPEC) strains isolated from cases of diarrhoea were examined. All except two strains adhered to HEp-2 cells in a localised adherence-like (LAL) pattern. With the exception of two strains, all were fluorescent actin staining (FAS) positive. Gentamicin HEp-2 invasion assay studies showed that all strains were invasive. Transmission electron microscopy of infected HEp-2 cells showed the characteristic attaching and effacing lesion and invasion of the cultured cells. Of the nine strains that hybridised with a DNA probe for alpha-haemolysin, five were haemolytic within 3 h of incubation, while the remaining strains were haemolytic only after incubation for 24 h. Three strains produced enterohaemolysin on blood agar. None of the 31 strains of E. coli induced fluid accumulation in the rabbit intestinal loop assay or displayed cytotoxic effects in HeLa and Vero cells. All the strains belonging to serotypes O26:H11, O26:H- and 0119:H2 expressed intimin beta, whereas all the strains from serotype O55:H7 expressed intimin gamma. The strains belonging to serogroup O111 expressed a non-typable intimin. The participation of intimin in LAL was supported by adhesion inhibition experiments in which antibodies to intimin significantly reduced the level of LAL.
- Published
- 1999
- Full Text
- View/download PDF
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