Variants of astA gene among extra-intestinal Escherichia coli of human and avian origin.

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.

Methylation pattern of THBS1, GATA-4, and HIC1 in pediatric and adult patients infected with Helicobacter pylori.

BACKGROUND: Helicobacter pylori infection is usually acquired in childhood and persists into adulthood if untreated. The bacterium induces a chronic inflammatory response, which is associated with epigenetic alterations in oncogenes, tumor-suppressor genes, cell-cycle regulators, and cell-adhesion molecules. AIM: The aim of this study was to analyze the effect of H. pylori infection on the methylation status of Thrombospondin-1 (THBS1), Hypermethylated in cancer 1 (HIC1) and Gata binding protein-4 (GATA-4) in gastric biopsy samples from children and adults infected or uninfected with the bacterium and in samples obtained from gastric cancer patients. METHODS: The methylation pattern was analyzed with methylation-specific PCR. RESULTS: Our results showed that H. pylori infection was associated with methylation of the promoter regions of the THBS1 and GATA-4 genes in pediatric and adult samples (p < 0.01). HIC1 showed the lowest level of methylation, which was not an early event during gastric carcinogenesis. CONCLUSIONS: The results from this study indicate that methylation of THBS1 and GATA-4 occurs in the early stages of chronic gastritis and gastric cancer in association with H. pylori infection; however, in gastric cancer samples, other mechanisms cooperate with the down-regulation of these genes. Methylation of HIC1 may not be the principal mechanism implicated in its down-regulation in gastric cancer samples.

Methane production and small intestinal bacterial overgrowth in children living in a slum.

AIM: To analyze small intestinal bacterial overgrowth in school-aged children and the relationship between hydrogen and methane production in breath tests. METHODS: This transversal study included 85 children residing in a slum and 43 children from a private school, all aged between 6 and 10 years, in Osasco, Brazil. For characterization of the groups, data regarding the socioeconomic status and basic housing sanitary conditions were collected. Anthropometric data was obtained in children from both groups. All children completed the hydrogen (H(2)) and methane (CH(4)) breath test in order to assess small intestinal bacterial overgrowth (SIBO). SIBO was diagnosed when there was an increase in H(2) ≥ 20 ppm or CH(4) ≥ 10 ppm with regard to the fasting value until 60 min after lactulose ingestion. RESULTS: Children from the slum group had worse living conditions and lower nutritional indices than children from the private school. SIBO was found in 30.9% (26/84) of the children from the slum group and in 2.4% (1/41) from the private school group (P = 0.0007). Greater hydrogen production in the small intestine was observed in children from the slum group when compared to children from the private school (P = 0.007). A higher concentration of hydrogen in the small intestine (P < 0.001) and in the colon (P < 0.001) was observed among the children from the slum group with SIBO when compared to children from the slum group without SIBO. Methane production was observed in 63.1% (53/84) of the children from the slum group and in 19.5% (8/41) of the children from the private school group (P < 0.0001). Methane production was observed in 38/58 (65.5%) of the children without SIBO and in 15/26 (57.7%) of the children with SIBO from the slum. Colonic production of hydrogen was lower in methane-producing children (P = 0.017). CONCLUSION: Children who live in inadequate environmental conditions are at risk of bacterial overgrowth and methane production. Hydrogen is a substrate for methane production in the colon.

Diffuse and enteroaggregative patterns of adherence of escherichia coli isolated from stools of children in northeastern Brazil

Childhood diarrheal diseases remain highly endemic in northeastern Brazil. The attributable fraction of all diarrheal diseases among children less than 2 years of age due to Escherichia coli was examined in a 2 year prospective study in two large urban centers of Brazil. Between May 1997 and June 1999, fecal E.coli isolates from 237 children with diarrhea (217 acute and 20 persistent cases) and 231 children without diarrhea (controls) attending two hospitals in Northeast Brazil were tested for their pattern of adherence to HEp-2 cells and for colony hybridization with DNA probes specific for the six pathotypes of diarrheagenic E.coli. Enteroinvasive E.coli, enterotoxigenic E.coli and enterohemorrhagic E.coli were not isolated from any children. Diffusely adherent E.coli (DAEC) and enteroaggregative E.coli (EAEC) were the most frequent isolates with similar frequencies from children with or without diarrhea. Atypical EPEC (EAF-negative) strains were isolated with similar frequency from both cases 5.5 per cente and controls 5.6 per cente. Enteropathogenic E.coli (typical EPEC) strains, characterized by localized adherence pattern of adherence, hybridization with the EAF probe, and belonging to the classical O serogroups, were significantly associated with diarrhea (P=0.03). These E.coli strains associated with diarrhea accounted for 9 per cente of all children with diarrhea. Collectively, in Northeast Brazil, E.coli strains comprise a small proportion of severe diarrhea prevalence in children.

Pesquisa de gliadina em medicamento: informação relevante para a orientação de pacientes com doença celíaca / Assessment of gliadin in pharmaceutical products: important information to the orientation of celiac disease patients

BACKGROUND: Some drugs might contain gliadin which can be dangerous for celiac disease patients. OBJECTIVE: Detect gliadin in pharmaceutical products commonly used in Brazil. METHODS: We analyzed 78 pharmaceutical products selected aleatory from a list of 180 products most frequently sold at Brazilian community pharmacies. The analyzed samples were analgesics (n = 9), anthelmintics (n = 3), antacids (n = 8), antibiotics (n = 13), anticholesteremics (n = 1), anticonvulsants (n = 2), antidepressants (n = 2), antiemetics (n = 3), antihypertensives (n = 3), antihistaminics (n = 3), anti-inflammatories (n = 7), antipyretics (n = 2), bronchodilators (n = 1), laxatives (n = 1), oral contraceptives (n = 5) and vitamins (n = 10). The samples were analyzed by enzyme immunoassay based on monoclonal antibodies omega-gliadins, the elected technique according to the Codex Alimentarius Commission WHO/FAO. All samples were analyzed in duplicate. The sensitivity of this test is 4 mg of gliadin/100 g of product. RESULTS: Only one (1.3%) out of 78 pharmaceutical products contained detectable amounts of gliadin (5.5 mg/100 g). The active ingredient of this drug is ranitidine. According to the Codex Alimentarius Commission WHO/FAO the intake of 10 mg of gliadin/day should not be exceeded by celiac disease patients. Considering the amount of gliadin in each capsule of ranitidine, the ingested quantity would be lower than the maximum allowed for celiac patients. CONCLUSIONS: In this study gliadin was not detected in pharmaceutical products in harmful amount for celiac disease patients

The gut at war: the consequences of enteropathogenic Escherichia coli infection as a factor of diarrhea and malnutrition

Diarrheal disease is still the most prevalent and important public health problem in developing countries, despite advances in knowledge, understanding, and management that have occurred over recent years. Diarrhea is the leading cause of death in children under 5 years of age. The impact of diarrheal diseases is more severe in the earliest periods of life, when taking into account both the numbers of episodes per year and hospital admission rates. This narrative review focuses on one of the major driving forces that attack the host, namely the enteropathogenic Escherichia coli (EPEC) and the consequences that generate malnutrition in an early phase of life. EPEC serotypes form dense microcolonies on the surface of tissue-culture cells in a pattern known as localized adherence (LA). When EPEC strains adhere to epithelial cells in vitro or in vivo they cause characteristic changes known as Attaching and Effacement (A/E) lesions. Surface abnormalities of the small intestinal mucosa shown by scanning electron microscopy in infants with persistent diarrhea, although non-specific, are intense enough to justify the severity of the clinical aspects displayed in a very young phase in life. Decrease in number and height of microvilli, blunting of borders of enterocytes, loss of the glycocalyx, shortening of villi and presence of a mucus pseudomembrane coating the mucosal surface were the abnormalities observed in the majority of patients. These ultrastructural derangements may be due to an association of the enteric enteropathogenic agent that triggers the diarrheic process and the onset of food intolerance responsible for perpetuation of diarrhea. An aggressive therapeutic approach based on appropriate nutritional support, especially the utilization of human milk and/or lactose-free protein hydrolyzate-based formulas and the adequate correction of the fecal losses, is required to allow complete recovery from the damage caused by this devastating enteropathogenic agent

Adesäo de Escherichia coli a células HeLa: correlaçäo com sorogrupos, sorotipos e biosorotipos; aspectos genéticos da adesäo / Adhesion of Escherichia coli to HeLa cells: correlation with serogroups, serotypes and bioserotypes; genetic aspects of adhesion

Foram estudadas 450 amostras de Escherichia coli, pertencentes a 45 sorogrupos e subgrupos e 112 sorotipos, quanto à adesäo em células HeLa. Desses sorogurpos e subgrupos estudados, 17 apresentaram os padröes de adesäo localizada (AL), difusa (AD) ou localizada e difusa (AL/AD). Alguns sorogupos apresentaram mais que um padräo de adesäo. Entretanto, em cada sorotipo , o padräo de adesäo foi bastante consistente. Adesäo localizada foi encontrada mais frequentemente naqueles sorotipos considerados enteropatogênicos clássicos (EPEC) (93% apresentaram AL) do que entre outros sortipos (14%). A maioria das amostras dos sorotipos 055:H6, 086:H34, 0111ab:H, 0111ab:H2, 0119:H, 0ll9:H6, 0127:H e 0142:H6 apresentaram somente adesäo localizada. A adesäo difusa foi menos encontrada entre as EPEC (21%) do que entre os demais sorotipos (36%). Quando encontrada em sorotipos de EPEC, ou era acompanahada de adesäo localizada (3 amostras em 055:H, 1 em 025:H, 5 em 0111ab:H21, 2 em 0119: H18 e 1 em 0125: HND) ou era rara (1 entre 8 amostras em 055: H7 e 086: H34). A determinaçäo das características bioquímicas das amostras mostrou uma correlaçäo muito grande entre sorotipos imóveis e adesäo localizada. Na maioria dos sorogrupos, as amostras imóveis positivas para adesäo localizada apresentaram características bioquímicas idênticas as positivas dos sorotipos móveis do mesmo sorogrupo, sugerindo que as móveis deram origem ás imóveis por perda de flagelos. Em todos os sorotipos estudados, as amostras positivas para adesäo localizada apresentaram características bioquímicas diferentes das negativas para adesäo. O estudo da dinâmica localizada mostrou que esse padräo permanece constante durante todo o experimento. Das 450 amostras estudadas, 50 foram testadas quanto à adesäo em células Hep-2. Os padröes de adesäo encontrados foram idênticos aos demonstrados nas células HeLa. Usando uma sonda de DNA específica para adesäo localizada nas células Hep-2, foi demonstrado que os fatores que codificam a adesäo localizada e adesäo difusa säo geneticamente distintos. Somente as amostras que apresentavam adesäo localizada e difusa foram positivas com a sonda. As amostras que apresentavam adesäo difusa e as que näo aderiam foram negativas. A análise do conteúdo plasmidial mostrou que a maioria das amostras positivas para adesäo localizada possuía um plasmídio de peso molecular em torno de 55 a 70 megadáltona. Näo foi observado um único plasmídio de mesmo peso molecular, nas amostras posi