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- ItemSomente MetadadadosDiarrheagenic Escherichia coli(Soc Brasileira Microbiologia, 2016) Gomes, Tania Aparecida Tardelli [UNIFESP]; Elias, Waldir P.; Scaletsky, Isabel Cristina Affonso [UNIFESP]; Guth, Beatriz Ernestina Cabilio [UNIFESP]; Rodrigues, Juliana F.; Piazza, Roxane M. F.; Ferreira, Luis C. S.; Martinez, Marina B.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/).
- ItemAcesso aberto (Open Access)Estudos genéticos sobre a virulência de Escherichia coli enteroagregativa atípica(Universidade Federal de São Paulo (UNIFESP), 2006-12-31) Zamboni, Andresa [UNIFESP]; Scaletsky, Isabel Cristina Affonso [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Escherichia coli enteroaggregative (EAEC) is emerging as a significant diarrheal pathogen. EAEC is defined by its characteristic “stacked brick” aggregative adherence (AA) pattern of adherence to HEp-2 cells. Most EAEC strains harbor a 60 to 65-MDa virulence plasmid (pAA). A 1-Kb fragment of pAA, referred to as the AA probe or CVD432, has been widely used for epidemiological studies. The pAA also encodes AA fimbrae (AAF) I, II, and III; the transcriptional activator AggR; enteroaggregative heatstable enterotoxin 1 (EAST1); a 104-KDa cytotoxin designated Pet; the cryptic secreted protein Shf; and a novel antiaggregation protein (dispersin) encoded by the aap gene. In addition to the pAA plasmid, some EAEC strains express putative virulence factors that are encoded on the chromosome, including a 116-KDa secreted mucinase (Pic), yersiniabactin (Irp2), and the E. coli a-hemolysin (a-Hly). Shigella enterotoxin 1 (ShET1) is encoded by the antisense strand of the pic gene. Few studies have evaluated the prevalence of EAEC markers in probe-negative strains, reported by us as atypical EAEC. By using atypical EAEC strains isolated in a case-control study, we assessed the prevalence of putative virulence factors, such as AAF/I, AAF/II, AAF/III, AggR, Aap, EAST-1, Pet, Shf, ShET1/Pic, Irp2, and a-Hly, in an attempt to identify their roles as enteric virulence factors. The majority of strains carried two or more of the genes, with two being the modal value; but two strains isolated from a control did not test positive for any of the factors. The AAF, aggR, and aap genes were present in only a minority of strains. The astA, pet, shf, ShET1/pic, irp2 and hly genes were found more frequently in the patients than in the controls. The combination astA and shf was found in 16 strains (57%), followed by 7 strains (25%) possessing the combination astA, shf, and irp2. The common virulence markers found in strains included the Pet, EAST1, Shf, Irp2, ShET1/Pic, and Hly virulence markers. EAST1 and Shf were the most frequently detected markers (61%) in strains and were found to be significantly associated with diarrhea (P = 0,003 and P = 0,020, respectively). The majority (75%) of the EAEC isolates reacted with one of the antisera used. It was interesting that the strains belonging to serogroups O42, O126 and O162 were detected only in children with diarrhea.Plasmid analysis of 12 strains isolated from diarrhea showed that the majority of strains contained large plasmids. Two strains, one carrying only one plasmid (MA691-2) and another one any plasmid (RN153-1), were chosen for genetic studies on the identification of genes responsible for the AA phenotype. Plasmid from MA691-2 strain was transferred to E. coli K12 and no transformant or transconjugant harboring the plasmid or isogenic derivative strain lacking the plasmid was identified. A genomic cosmid library of EAEC RN153-1 was generated in E. coli K12, and the resulting clones were screened for aggregative adherence to HEp-2 cells. One cosmid clone, pVIII-F-1, exhibited the same adherence as the wild-type, albeit to a lesser extent. Transposon mutagenesis was utilized to identify the region of cosmid pVIII-F-1 responsible for the aggregative phenotype. Plasmid pBSL181 carrying mini-Tn10
- ItemSomente MetadadadosEtiology of childhood diarrhea in the northeast of Brazil: significant emergent diarrheal pathogens(Elsevier B.V., 2010-01-01) Ramos Moreno, Ana Carolina; Fernandes Filho, Antonio; Tardelli Gomes, Tania do Amaral [UNIFESP]; Ramos, Sonia T. S.; Montemor, Liana P. G.; Tavares, Vanessa C.; Santos Filho, Lauro dos; Irino, Kinue; Martinez, Marina Baquerizo; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Univ Fed Paraiba; Adolfo Lutz InstIn a study conducted in Joao Pessoa, northeast of Brazil, 2344 Escherichia coli isolated from 290 infants with diarrhea and 290 healthy matched controls were analyzed for virulence traits. Enteroaggregative E. coli (EAEC) was the most prevalent pathogen associated to acute diarrhea. Based on the results of colony blot hybridization, serotyping, and HEp-2 cell adherence assays, strains were separated in categories as typical enteropathogenic E. coli (EPEC) (1.7%), atypical EPEC (a-EPEC) (9.3%), EAEC (25%), enterotoxigenic E. coli (10%), and enteroinvasive E. coli (EIEC) (1.4%). No enterohemorrhagic E. coli strains were isolated. Other enteropathogens were found, including Salmonella (7.9%), Shigella spp. (4.1%), thermophilic Campylobacter spp. (2.4%), Giardia lamblia (9.3%), and Entamoeba histolytica (5.8%). All enteropathogens were associated with diarrhea (P < 0.01). However, the association was lower for EPEC and EIEC (P < 0.03). Different pathogens associated with diarrhea may have been changing in Brazil where EAEC and a-EPEC seem to be the most prevalent pathogens among them. (C) 2010 Elsevier Inc. All rights reserved.
- ItemSomente MetadadadosIce as a vehicle for diarrheagenic Escherichia coli(Elsevier B.V., 2004-02-15) Falcao, Juliana Pfrimer; Falcao, Deise Pasetto; Gomes, Tania Aparecida Tardelli [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Estadual PaulistaIn a recent study of the microbiological quality of commercial ice, 50 Escherichia coli isolates belonging to different serotypes were found. the potential hazard from these isolates was examined by testing their adherence patterns ill HeLa cells and searching for the presence of DNA sequences related to E. coli virulence properties. Twelve potentially diarrheagenic isolates were found and classified as enteroaggregative E. coli (EAEC) based oil their ability to produce aggregative adherence to HeLa cells. the remaining isolates were devoid of the virulence properties searched for. the EAEC isolates belonged to 10 different serotypes, among which O128ab:H35 is often found in diarrheic feces. None of these isolates reacted with a specific EAEC DNA probe or carried any of the known EAEC virulence genes. These data indicate that ice may be all important vehicle for transmission of enteropathogens, especially of the EAEC group. (C) 2003 Elsevier B.V. All rights reserved.
- ItemAcesso aberto (Open Access)A importância do tratamento em hospital-dia para a criança com subnutrição primária(Instituto de Estudos Avançados da Universidade de São Paulo, 2013-01-01) Albuquerque, Maria Paula de [UNIFESP]; Martins, Paula Andrea [UNIFESP]; Pires, Renata Cristina [UNIFESP]; Sawaya, Ana Lydia [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)We evaluated the impact of socioeconomic and maternal conditions, treatment frequency and frequency of infections, parasites and anemia in the increment of height for age (H/A) in children (< 5 years) undergoing treatment at day-hospital at a Center for Recovery and Nutritional Education (n = 57). Upper respiratory infections were the most frequent disease with positive association with the severity of undernutrition (p = 0.035) and age at admission (p = 0.001). In multiple regression analysis, the severity of undernutrition, low hemoglobin level, family income and the low frequency at the service were predictors of increment in stature (p < 0.05). The findings show the importance of treatment in day hospitals for undernourished children.
- ItemAcesso aberto (Open Access)Incidence of diarrhea in children living in urban slums in Salvador, Brazil(Brazilian Society of Infectious Diseases, 2008-02-01) Melo, Maria Clotildes Nunes de; Taddei, Jose Augusto de Aguiar Carrazedo [UNIFESP]; Diniz-Santos, Daniel Rui; Vieira, Camilo; Carneiro, Nadya Bustani; Melo, Rita Franca; Silva, Luciana Rodrigues; Federal University of Bahia Professor Hosannah Oliveira Pediatric Centre Division of Pediatric Gastroenterology and Hepatology; Universidade Federal de São Paulo (UNIFESP)Diarrhea remains a major health issue in developing countries, with high morbidity and mortality rates. Determining the incidence of acute diarrhea in children and its associated factors is crucial to the planning of preventive approaches. The objective of this study was to determine the incidence of diarrhea and to assess some relevant associated factors to it in children younger than 40 months living in two slums of Salvador, Brazil. This is the first prospective cohort, community-based study that was performed in two periurban slums of Salvador, Brazil. Eighty-four children younger than 40 months were randomly selected and visited every other day for one year. The chi-square test was used to evaluate the occurrence of diarrhea and its associated factors. During the surveillance period, 232 diarrhea episodes were identified, resulting in an incidence rate of 2.8 episodes/child/year. In average (mean value of 84 children),each child suffered 11.1 days of diarrhea per year, yielding an average duration of 3.9 days per episode. The highest incidence rates were found among children under one year old. Early weaning, male sex, malnutrition, having a mother younger than 25 years or who considered her child malnourished, missed immunizations and previous pneumonia were associated factors for suffering diarrheal episodes. The rates of incidence and duration of diarrhea that we found are in accordance to those reported by others. Additionally, our results reinforce the importance of environmental and health-related associated factors to the onset of diarrhea.
- ItemAcesso aberto (Open Access)Influence of environmental factors in the adherence of an atypical enteropathogenic Escherichia coli strain to epithelial cells(Biomed Central Ltd, 2014-12-20) Romao, Fabiano T. [UNIFESP]; Hernandes, Rodrigo T. [UNIFESP]; Yamamoto, Denise [UNIFESP]; Osugui, Lika [UNIFESP]; Popi, Ana Flavia [UNIFESP]; Gomes, Tania A. T. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Background: Attachment is essential to maintain bacteria at their preferential intestinal colonization sites. There is little information on the influence of different environmental conditions in the interaction of atypical enteropathogenic Escherichia coli (aEPEC) strains with epithelial cells. in this study, we evaluated the effect of different glucose (5 and 25 mM) and CO2 (0.03 and 5%) concentrations and presence of bile salts on the adhesiveness of the aEPEC strain 1551-2.Results: We found that a CO2-enriched atmosphere enhanced the adhesiveness of the aEPEC 1551-2 strain independently of glucose concentrations or presence of bile salts. Conversely, the presence of high glucose concentration altered the original localized adherence (LA) pattern observed at 5 mM glucose, which is characterized by the formation of compact bacterial clusters, to a hybrid adherence pattern (LA and an aggregative adherence-like pattern). in addition, at high glucose concentration, there was increased expression of the fimA gene, which encodes the major subunit of type 1 pilus (T1P), and an isogenic fimA mutant displayed only LA. the presence of bile salts did not interfere with the adhesion properties of the 1551-2 strain to HeLa cells.Conclusions: Our data suggest that a CO2-enriched atmosphere could favor aEPEC adhesion to the host cells, whereas enhanced T1P production under high glucose concentration could allow bacteria to access more extensive intestinal colonization sites in the host at the beginning of the infectious process.
- ItemAcesso aberto (Open Access)Ocorrência e caracterização de eventos de invasão de linhagens celulares cultivadas in vitro por amostras de Escherichia coli enteropatogênica (EPEC) atípica(Universidade Federal de São Paulo (UNIFESP), 2009-03-25) Yamamoto, Denise [UNIFESP]; Gomes, Tania Aparecida Tardelli [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Enteropathogenic Escherichia coli (EPEC) produce attaching/effacing (A/E) lesions on eukaryotic cells mediated by the outer membrane adhesin Intimin. EPEC are subgrouped into typical (tEPEC) and atypical (aEPEC). We have recently demonstrated that aEPEC strain 1551-2 (serotype O non-typable, non-motile) invades HeLa cells by a process dependent on the expression of intimin subtype omicron. In this study, we evaluated whether aEPEC strains expressing other intimin subtypes are also invasive using the quantitative gentamicin protection assay. We also evaluated whether aEPEC invade intestinal differentiated T84 cells. Five of six strains invaded HeLa and T84 cells in a range of 13.3%-20.9% and 5.8%-17.8%, respectively, of the total cellassociated bacteria. The strains studied were significantly more invasive than prototype tEPEC strain E2348/69 (1.4% and 0.5% in HeLa and T84 cells, respectively). aEPEC strain 1551-2 was also tested in differentiated Caco-2 cells, resulting in an invasion index similar to that obtained in T84 cells (7.5%±1.7%). This strain was also significantly more invasive than prototype tEPEC strain E2348/69 (1.8%±0.6%). Invasiveness of T84 cells was confirmed by transmission electron microscopy. We also showed that invasion of HeLa cells by aEPEC 1551-2 depended on actin filaments, but not on microtubules. In addition, infection of non-differentiated monolayers and disruption of tight junctions enhanced its invasion efficiency in T84 cells, suggesting preferential invasion via a non-differentiated surface. In summary, aEPEC strains may invade intestinal cells in vitro with varying efficiencies and independently of the intimin subtype.
- ItemAcesso aberto (Open Access)Pathophysiology of enteroaggregative Escherichia coli infection: an experimental model utilizing transmission electron microscopy(Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE Colégio Brasileiro de Cirurgia Digestiva - CBCD Sociedade Brasileira de Motilidade Digestiva - SBMD Federação Brasileira de Gastroenterologia - FBGSociedade Brasileira de Hepatologia - SBHSociedade Brasileira de Endoscopia Digestiva - SOBED, 2010-09-01) Andrade, Jacy Alves Braga de [UNIFESP]; Freymüller-Haapalainen, Edna [UNIFESP]; Fagundes-Neto, Ulysses; Division of Pediatric Gastroenterology; Universidade Federal de São Paulo (UNIFESP)CONTEXT: Enteroaggregative Escherichia coli strains have been associated with persistent diarrhea in several developing countries. In vivo procedures with animal models as rat, rabbit and gnotobiotic piglets intestinal loops, in vitro assays with cellular lines like T84, Caco 2, HT29, HeLa e HEp-2 and in vitro organ culture with intestinal fragments have been applied to study these bacteria and their pathogenicity. OBJECTIVES: The present experimental research assessed the pathogenic interactions of three enteroaggregative Escherichia coli strains, using the in vitro organ culture, in order to observe and compare alterations in different regions of both, the ileal and the colonic mucosa. METHODS: This study applied intestinal fragments from terminal ileum and colon that were excised from pediatric and adult patients that underwent colonoscopic procedures. Tissue was fixed for transmission electron microscopic study. Each bacterium was tested with three intestinal fragments for each region. RESULTS: Enteroaggregative Escherichia coli strains colonized and provoked citotoxic effects in the ileal and colonic mucosa. Total or partial villi destruction, vacuolization of basal cytoplasm of the enterocytes, epithelium detachment, derangement of the structure and epithelial cell extrusion in ileal mucosa could explain the perpetuation of the diarrhea. Bacterial aggregates were seen in intestinal lumen associated with mucus and cellular debris and in the intercellular spaces of the destroyed epithelium, suggesting bacterial invasion that seemed to be secondary to the destruction of the tissue. CONCLUSIONS: Pathogenesis of persistent diarrhea should include alterations in the small bowel structures where the digestive-absorptive functions take place. In the colonic mucosa the inflammatory lesions could explain the occurrence of colitis.
- ItemAcesso aberto (Open Access)Prevalência de distúrbios gastrointestinais funcionais em lactentes nascidos prematuros(Universidade Federal de São Paulo (UNIFESP), 2019-12-02) Gondim, Marcela Montenegro Braga Barroso [UNIFESP]; Morais, Mauro Batista de [UNIFESP]; Goulart, Ana Lucia [UNIFESP]; http://lattes.cnpq.br/5519219079407797; http://lattes.cnpq.br/5056114729141952; Universidade Federal de São Paulo (UNIFESP)Objective: To compare the prevalence of functional gastrointestinal disorders in preterm infants with those of term infants using the Rome IV criteria. Additionally, to evaluate whether invasive procedures during the neonatal period are associated with a higher chance of developing functional gastrointestinal disorders in preterm infants. Methods: Controlled cross-sectional study nested in a retrospective cohort of preterm infants who were compared with term infants for functional gastrointestinal disorders. In the preterm group, infants born with a gestational age <37 weeks were included in the study, and in the term group, infants born with a gestational age > 37 weeks and with a birth weight above 2500 grams were included. A face-to-face medical consultation was performed by a single pediatric gastroenterologist for information on the gestational and neonatal period and information on clinical digestive manifestations. Rome IV criteria were used for diagnosing functional gastrointestinal disorders.Results: We studied 197 infants (<24 months), 99 preterm infants and 98 term infants. Infant regurgitation was more prevalent in term infants (35.1% and 15.6%, p <0.001). The prevalence of other functional gastrointestinal disorders in preterm infants was not different, according to statistical analysis, compared to term infants, respectively: infant colic (10.7% and 4.3%; p= 0.360), functional constipation (17.2% and 9.2%; p= 0.098), functional diarrhea (4.6% and 0.0%; p= 0.274) and infant dyschezia (9.3% and 7.5%; p= 0.735). No relationship was found between invasive procedures performed in the neonatal period and higher risk for developing functional gastrointestinal disorders in preterm infants. Conclusion: In the studied population, preterm infants had no higher prevalence of functional gastrointestinal disorders. No relation was found in preterm infants with invasive diagnostic and therapeutic procedures and the development of gastrointestinal manifestations.