Characterization of atypical enteropathogenic Escherichia coli strains that express typical localized adherence in HeLa cells in the absence of the bundle-forming pilus

The characterization of nine atypical enteropathogenic Escherichia coli strains expressing localized adherence in HeLa cells in the absence of the bundle-forming pilus revealed a diversity of serotypes, plasmids, and virulence genes. Although the strains lacked known E. coli adhesin genes, the identification of new adhesins could contribute to the characterization of similar enteropathogenic E. coli isolates.Universidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilInst Butanan, Lab Biol Cellular, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc

Pandemic extra-intestinal pathogenic Escherichia coli (ExPEC) clonal group O6-B2-ST73 as a cause of avian colibacillosis in Brazil

Extra-intestinal pathogenic Escherichia coli (ExPEC) represent an emerging pathogen, with pandemic strains increasingly involved in cases of urinary tract infections (UTIs), bacteremia, and meningitis. In addition to affecting humans, the avian pathotype of ExPEC, avian pathogenic E. coli (APEC), causes severe economic losses to the poultry industry. Several studies have revealed overlapping characteristics between APEC and human ExPEC, leading to the hypothesis of a zoonotic potential of poultry strains. However, the description of certain important pandemic clones, such as Sequence Type 73 (ST73), has not been reported in food sources. We characterized 27 temporally matched APEC strains from diverse poultry farms in Brazil belonging to the O6 serogroup because this serogroup is frequently described as a causal factor in UTI and septicemia in humans in Brazil and worldwide. The isolates were genotypically characterized by identifying ExPEC virulence factors, phylogenetically tested by phylogrouping and multilocus sequence type (MLST) analysis, and compared to determine their similarity employing the pulsed field gel electrophoresis (PFGE) technique. The strains harbored a large number of virulence determinants that are commonly described in uropathogenic E. coli (UPEC) and sepsis associated E. coli (SEPEC) strains and, to a lesser extent in neonatal meningitis associated E. coli (NMEC), such as pap (85%), sfa (100%), usp (100%), cnf1 (22%), kpsMTII (66%), hlyA (52%), and ibeA (4%). These isolates also yielded a low prevalence of some genes that are frequently described in APEC, such as iss (37%), tsh, ompT, and hlyF (8% each), and cvi/cva (0%). All strains were classified as part of the B2 phylogroup and sequence type 73 (ST73), with a cluster of 25 strains showing a clonal profile by PFGE. These results further suggest the zoonotic potential of some APEC clonal lineages and their possible role in the epidemiology of human ExPEC, in addition to providing the first description of the O6-B2-ST73 clonal group in poultry.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo - FAPESPUniv Sao Paulo, Dept Pathol, Fac Med Vet & Zootecnia, Sao Paulo, BrazilUniv Sao Paulo, Dept Vet Prevent Med, Fac Med Vet & Zootecnia, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Microbiol Immunol & Parasitol, Escola Paulista Med, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Microbiol Immunol & Parasitol, Escola Paulista Med, Sao Paulo, BrazilFAPESP: 05/57500-9-TFAPESP: 11/182046-TFAPESP: 14/11523-7]Web of Scienc

Laboratory evaluation on pathogenic potentialities of Vibrio furnissii

Sixteen strains of Vibrio furnissii recovered from 16 Brazilian patients with diarrhea were screened for virulence-associated factors. All strains were non-invasive, non-fimbriated, and did not produce either enterotoxins or cholera-like toxin. In contrast, most were hemolytic on blood agar and their broth-culture supernatants damaged HeLa cell monolayers. These cytolysins, as accepted for other enteropathogenic members of the family Vibrionaceae, might be determinants of pathogenicity in V. furnissii-mediated enteritis.Universidade Federal de Pernambuco Laboratório Keizo AsamiEscola Paulista de MedicinaUNIFESP, EPMSciEL

Expressão de aderência agregativa em células HeLa por amostras de E. coli isoladas de eqüinos doentes

The virulence attributes of 56 Escherichia coli strains isolated from sick horses (secretions of uterine cervices; gastrointestinal and lung fragments of necropsy; diarrheic feces, and tracheal washings) was examined by determining their adherence pattern to HeLa cells and searching for the presence of virulence genes of the various E. coli pathotypes. Two non-adherent strains presented astA, which encodes the enteroaggregative E. coli heat-stable toxin. Twenty-seven strains (48.2%) adhered to HeLa cells, 21 (77.8%) of which presented the aggregative adherence pattern (AA) that characterize the Enteroaggregative E. coli pathotype (EAEC). Nine of the strains presenting AA were isolated from secretions of uterine cervix, including one carrying virulence genes of the EAEC pathotype (aggR,aap,irp2, and pic). This is the first description of the AA phenotype amongst E. coli strains from sick horses. Such strains should be further evaluated regarding their potential role in the pathogenesis of diverse equine diseases and as reservoirs of human infections.Características de virulência de 56 amostras de Escherichia coli isoladas de eqüinos doentes (secreção de colo uterino, fragmentos de necrópsia do trato gastrointestinal e de pulmões, fezes diarréicas e lavado traqueal) foram examinadas para determinar o padrão de aderência em células HeLa e pesquisar a presença de genes de virulência de vários patotipos de E. coli. Duas amostras não aderentes apresentaram astA, gene que codifica a toxina termo-estável de E. coli enteroagregativa. Das vinte e sete amostras (48,2%) que aderiram a células HeLa, 21 (77,8%) apresentaram o padrão de aderência agregativa (AA) que caracteriza o patotipo de E. coli Enteroagregativa (EAEC). Nove destas amostras que apresentaram AA foram isoladas de secreção de colo uterino, incluindo uma que apresentava genes de virulência de patotipos de EAEC (aggR,aap,irp2 e pic). Esta é a primeira descrição do fenótipo AA em amostras de cavalos doentes. Estas amostras deverão ser melhor avaliadas em relação a sua potencial função na patogênese de diferentes doenças eqüinas, bem como à possibilidade destes animais representarem um reservatório de infecções humanas causadas por esta bactéria.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaJockey Club de São PauloLaboratório Clínico-Experimental de Gastroenterologia PediátricaUNIFESP, EPMSciEL

Frequency and characteristics of diarrhoeagenic Escherichia coli strains isolated from children with and without diarrhoea in Rio de Janeiro, Brazil

The frequency of diarrhoeagenic Escherichia coli (DEC) strains was investigated in 253 children up to 3 years old, with (patient group, PG, 199 children) and without (control group, CG, 54 children) diarrhoea, living in Rio de Janeiro, Brazil. DEC strains were detected in 70 (27.6%) children, including 54 (27.1%) with diarrhoea and 16 (29.6%) without diarrhoea. Enteroaggregative E. coli (EAEC) was the most frequent DEC category, accounting for 14.6% of the isolates in the PG and for 11.1% in the CG. E. coli strains carrying enteropathogenic E. coli (EPEC) virulence markers showed higher incidence in the CG (12.9%) than in the PG (8.0%). E. coli strains belonging to non-classical, EPEC groups that carried eae only or eae and bfpA, designated as attaching-effacing E. coli (AEEC) were the most frequent (79.1%). Simultaneous presence of multiple EPEC virulence factors (EAF/eae/bfpA) were only detected among strains isolated from the PG. Enterotoxigenic E. coli (ETEC) strains were isolated from 5.5% of the children in the CG and from 3.5% of those in the PG. Most of the ETEC isolates were LT-probe positive (70%) and none carried both LT-I and ST-I probe sequences. One enteroinvasive E. coli (EIEC) strain was recovered from a child with diarrhoea. No stx-probe positive E. coli strains were detected. Overall, DEC strains were not found to be significantly associated with diarrhoea (p > 0.05). However, the higher incidence of EAEC, the most frequent DEC category, among children with diarrhoea, suggests a potential role of EAEC as an important enteric pathogen in the community investigated. (C) 2003 the British Infection Society. Published by Elsevier B.V. All rights reserved.Escola Nacl Saude Publica, Fdn Oswaldo Cruz, Lab Epidemiol Mol, BR-148060 Rio de Janeiro, RJ, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, SP, BrazilUniv Estado Rio de Janeiro, Rio de Janeiro, RJ, BrazilInst Adolfo Lutz Registro, São Paulo, SP, BrazilUniv Fed Rio de Janeiro, Rio de Janeiro, RJ, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, SP, BrazilWeb of Scienc

Diarrheagenic Escherichia coli

Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes. (C) 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Univ Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, SP, BrazilInst Butantan, Lab Bacterol, Sao Paulo, SP, BrazilUniv Sao Paulo, Inst Ciencias Biomed, Dept Microbiol, Sao Paulo, SP, BrazilUniv Sao Paulo, Fac Ciencias Farmaceut, Dept Anal Clin & Toxicol, Sao Paulo, SP, BrazilUniversidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Microbiologia, Imunologia e Parasitologia, São Paulo, SP, BrazilWeb of Scienc