Enteropathogenic Escherichia coli (EPEC) expressing a non-functional bundle-forming pili (BFP) also leads to increased growth failure and intestinal inflammation in C57BL/6 mice.

Bundle-forming pili (BFP) are implicated in the virulence of typical enteropathogenic E. coli (EPEC), resulting in enhanced colonization and mild to severe disease outcomes; hence, non-functional BFP may have a major influence on disease outcomes in vivo. Weaned antibiotic pre-treated C57BL/6 mice were orally infected with EPEC strain UMD901 (E2348/69 bfpA C129S); mice were monitored daily for body weight; stool specimens were collected daily; and intestinal tissues were collected at the termination of the experiment on day 3 post-infection. Real-time PCR was used to quantify fecal shedding and tissue burden. Intestinal inflammatory biomarkers lipocalin-2 (LCN-2) and myeloperoxidase (MPO) were also assessed. Infection caused substantial body weight loss, bloody diarrhea, and intestinal colonization with fecal and intestinal tissue inflammatory biomarkers that were comparable to those previously published with the wild-type typical EPEC strain. Here we further report on the evaluation of an EPEC infection model, showing how disruption of bfp function does not impair, and may even worsen diarrhea, colonization, and intestinal disruption and inflammation. More research is needed to understand the role of bfp in pathogenicity of EPEC infections in vivo.

Molecular characterization of virulence and antimicrobial resistance profile of Shigella species isolated from children with moderate to severe diarrhea in northeastern Brazil.

Molecular characterization of virulence and antimicrobial resistance profiles were determined for Shigella species isolated from children with diarrhea in Fortaleza, Brazil. Fecal specimens were collected along with socioeconomic and clinical data from children with moderate to severe diarrhea requiring emergency care. Shigella spp. were isolated by standard microbiological techniques, and we developed 4 multiplex polymerase chain reaction assays to detect 16 virulence-related genes (VRGs). Antimicrobial susceptibility tests were performed using disk diffusion assays. S. flexneri and S. sonnei were the predominant serogroups. S. flexneri was associated with low monthly incomes; more severe disease; higher number of VRGs; and presence of pic, set, and sepA genes. The SepA gene was associated with more intense abdominal pain. S. flexneri was correlated with resistance to ampicillin and chloramphenicol, whereas S. sonnei was associated with resistance to azithromycin. Strains harboring higher numbers of VRGs were associated with resistance to more antimicrobials. We highlight the correlation between presence of S. flexneri and sepA, and increased virulence and suggest a link to socioeconomic change in northeastern Brazil. Additionally, antimicrobial resistance was associated with serogroup specificity in Shigella spp. and increased bacterial VRGs.

Improvement of intestinal permeability with alanyl-glutamine in HIV patients: a randomized, double blinded, placebo-controlled clinical trial.

CONTEXT: Glutamine is the main source of energy of the enterocyte and diarrhea and weight loss are frequent in HIV infected patients. OBJECTIVE: To determine the effect of alanyl-glutamine supplementation on intestinal permeability and absorption in these patients. METHODS: Randomized double-blinded, placebo-controlled study using isonitrogenous doses of alanyl-glutamine (24 g/day) and placebo (glycine, 25 g/day) during 10 days. Before and after this nutritional supplementation lactulose and mannitol urinary excretion were determined by high performance liquid chromatography. RESULTS: Forty six patients with HIV/AIDS, 36 of whom were male, with 37.28 ± 3 (mean ± standard error) years were enrolled. Twenty two and 24 subjects were treated with alanyl-glutamine and with glycine respectively. In nine patients among all in the study protocol that reported diarrhea in the 14 days preceding the beginning of the study, mannitol urinary excretion was significantly lower than patients who did not report this symptom [median (range): 10.51 (3.01-19.75) vs. 15.37 (3.93-46.73); P = 0.0281] and lactulose/mannitol ratio was significantly higher [median (range): 0.04 (0.00-2.89) vs. 0.02 (0.00-0.19); P = 0.0317]. There was also a significant increase in mannitol urinary excretion in the group treated with alanyl-glutamine [median (range): 14.38 (8.25-23.98) before vs 21.24 (6.27-32.99) after treatment; n = 14, P = 0.0382]. CONCLUSION: Our results suggest that the integrity and intestinal absorption are more intensely affected in patients with HIV/AIDS who recently have had diarrhea. Additionally, nutritional supplementation with alanyl-glutamine was associated with an improvement in intestinal absorption.

IMPROVEMENT OF INTESTINAL PERMEABILITY WITH ALANYL-GLUTAMINE IN HIV PATIENTS: a randomized, double blinded, placebo-controlled clinical trial

Context Glutamine is the main source of energy of the enterocyte and diarrhea and weight loss are frequent in HIV infected patients. Objective To determine the effect of alanyl-glutamine supplementation on intestinal permeability and absorption in these patients. Methods Randomized double-blinded, placebo-controlled study using isonitrogenous doses of alanyl-glutamine (24 g/day) and placebo (glycine, 25 g/day) during 10 days. Before and after this nutritional supplementation lactulose and mannitol urinary excretion were determined by high performance liquid chromatography. Results Forty six patients with HIV/AIDS, 36 of whom were male, with 37.28 ± 3 (mean ± standard error) years were enrolled. Twenty two and 24 subjects were treated with alanyl-glutamine and with glycine respectively. In nine patients among all in the study protocol that reported diarrhea in the 14 days preceding the beginning of the study, mannitol urinary excretion was significantly lower than patients who did not report this symptom [median (range): 10.51 (3.01–19.75) vs. 15.37 (3.93–46.73); P = 0.0281] and lactulose/mannitol ratio was significantly higher [median (range): 0.04 (0.00–2.89) vs. 0.02 (0.00–0.19); P = 0.0317]. There was also a significant increase in mannitol urinary excretion in the group treated with alanyl-glutamine [median (range): 14.38 (8.25–23.98) before vs 21.24 (6.27–32.99) after treatment; n = 14, P = 0.0382]. Conclusion Our results suggest that the integrity and intestinal absorption are more intensely affected in patients with HIV/AIDS who recently have had diarrhea. Additionally, nutritional supplementation with alanyl-glutamine was associated with an improvement in intestinal absorption. .

Contexto A glutamina é a principal fonte de energia do enterócito e diarreia e perda de peso são frequentes em pacientes infectados pelo HIV. Objetivo Determinar o efeito da alanil-glutamina sobre a permeabilidade e a absorção intestinais nesses pacientes. Métodos Estudo duplo-cego, randomizado, controlado por placebo, utilizando doses isonitrogênicas de alanil-glutamina (24 g/dia) e de placebo (glicina, 25 g/dia) durante 10 dias. Antes e depois dessa suplementação nutricional a excreção urinária de lactulose e manitol foi determinada por cromatografia líquida de alta performance. Resultados Quarenta e seis pacientes com HIV/AIDS, sendo 36 do sexo masculino, com 37,28 ± 3 anos (média ± erro padrão) foram incluídos. Vinte e dois e 24 indivíduos foram tratados com alanil-glutamina e com glicina, respectivamente. Nos nove pacientes que relataram ter apresentado diarreia nos 14 dias anteriores ao início do estudo, a excreção urinária de manitol foi significativamente menor do que nos pacientes que não referiram essa queixa [mediana (intervalo): 10,51 (3,01-19,75) vs 15,37 (3,93-46,73), P = 0,0281] e a razão lactulose/manitol foi significativamente mais elevada [mediana (intervalo): 0,04 (0,00-2,89) vs 0,02 (0,00-0,19), P = 0,0317]. Constatou-se também aumento significativo na excreção urinária de manitol no grupo tratado com alanil-glutamina [mediana (intervalo): 14,38 (8,25-23,98), antes vs 21,24 (6,27-32,99) após o tratamento, n = 14, P = 0,0382]. Conclusão Os resultados do presente estudo sugerem que a integridade e a absorção intestinais são mais intensamente afetadas em pacientes com HIV/AIDS que tiveram diarreia recentemente. Adicionalmente, a suplementação ...

Prevalence of enteroaggregative Escherichia coli and its virulence-related genes in a case-control study among children from north-eastern Brazil.

Enteroaggregative Escherichia coli (EAEC) is an important agent that causes endemic and epidemic diarrhoeal diseases worldwide. Several EAEC virulence-related genes (VRGs) have been described but their role in the clinical outcome of infection is not completely defined. This study investigated the prevalence of EAEC and potential associations of its VRGs with risk of or protection from diarrhoeal diseases in children from urban communities in north-eastern Brazil. The case-control study included 166 children, who had their stools evaluated for the EAEC diagnostic genes (aaiC and aatA) using PCR. Positive samples were further analysed by multiplex PCR and identified 18 VRGs. EAEC was found in the same proportion in both groups (41%). The plasmid-borne gene encoding a hexosyltransferase homologue (capU) was the most frequently detected (89.6%), followed by dispersin protein (aap, 58.2%) and EAEC HilA homologue (eilA, 57.8%). The AAF/III fimbrial subunit (agg3A) gene was observed at lower frequency (1.5%). Plasmid-encoded toxin (pet) or AAF/II fimbrial subunit (aafA) was associated significantly with disease. AAF/IV fimbrial subunit (agg4A) or hypothetical plasmid-encoded haemolysin (orf61) was detected significantly more in controls than in children with diarrhoea. In addition, one set of genes in combination, aaiC and agg3/4C but lacking agg4A and orf61, was associated with diarrhoea cases; and another one, orf61 in the absence of pet and aafA, was correlated with control children. These data confirm a high prevalence, endemicity and heterogeneity of EAEC strains in the developing urban areas of north-eastern Brazil. Statistical correlation between cases and controls was seen with either isolated or combined sets of genes, suggesting that the pathophysiology of EAEC infection involves a complex and dynamic modulation of several VRGs.

Enteroaggregative Escherichia coli quantification in children stool samples using quantitative PCR.

Enteroaggregative Escherichia coli (EAEC) is a common cause of infectious diarrhea, especially in children living in poor-resource countries. In this article, we present a SYBR Green-based real-time polymerase chain reaction (qPCR) method for quantitative detection of EAEC in DNA directly extracted from human stool samples. To test the proposed qPCR system, we examined specificity, sensitivity, repeatability, and also the degree of DNA extraction efficiency using EAEC strain 042 spiked into EAEC-free stool sample. The specificity of this assay was proved using six strains of EAEC, seven strains of other E. coli types, and one strain of Shigella. The detection limit of qPCR was 67 CFU/reaction. In naturally infected stool samples, we found EAEC in quantities varying from 6.7 × 10(5) to 2 × 10(9 ) CFU/g of feces. We could not detect any reduction after stool DNA extraction for the amounts of 10(7) and 10(6) CFU/mL of spiked EAEC. This qPCR assay is simple, rapid, reproducible, sensitive, specific, and allows rapid EAEC quantification to be used in a variety of further EAEC studies. This new quantitative method provides a relatively simple means to quantify EAEC, which will likely be key to understanding the pathophysiology and impact of EAEC infection.

Adenosine deaminase inhibition prevents Clostridium difficile toxin A-induced enteritis in mice.

Toxin A (TxA) is able to induce most of the classical features of Clostridium difficile-associated disease in animal models. The objective of this study was to determine the effect of an inhibitor of adenosine deaminase, EHNA [erythro-9-(2-hydroxy-3-nonyl)-adenine], on TxA-induced enteritis in C57BL6 mice and on the gene expression of adenosine receptors. EHNA (90 µmol/kg) or phosphate-buffered saline (PBS) was injected intraperitoneally (i.p.) 30 min prior to TxA (50 µg) or PBS injection into the ileal loop. A(2A) adenosine receptor agonist (ATL313; 5 nM) was injected in the ileal loop immediately before TxA (50 µg) in mice pretreated with EHNA. The animals were euthanized 3 h later. The changes in the tissue were assessed by the evaluation of ileal loop weight/length and secretion volume/length ratios, histological analysis, myeloperoxidase assay (MPO), the local expression of inducible nitric oxide synthase (NOS2), pentraxin 3 (PTX3), NF-κB, tumor necrosis factor alpha (TNF-α), and interleukin-1ß (IL-1ß) by immunohistochemistry and/or quantitative reverse transcription-PCR (qRT-PCR). The gene expression profiles of A1, A(2A), A(2B), and A3 adenosine receptors also were evaluated by qRT-PCR. Adenosine deaminase inhibition, by EHNA, reduced tissue injury, neutrophil infiltration, and the levels of proinflammatory cytokines (TNF-α and IL-1ß) as well as the expression of NOS2, NF-κB, and PTX3 in the ileum of mice injected with TxA. ATL313 had no additional effect on EHNA action. TxA increased the gene expression of A1 and A(2A) adenosine receptors. Our findings show that the inhibition of adenosine deaminase by EHNA can prevent Clostridium difficile TxA-induced damage and inflammation possibly through the A(2A) adenosine receptor, suggesting that the modulation of adenosine/adenosine deaminase represents an important tool in the management of C. difficile-induced disease.

Campylobacter jejuni and Campylobacter coli in children from communities in Northeastern Brazil: molecular detection and relation to nutritional status.

This study determined the prevalence of Campylobacter jejuni/coli and its relation with nutritional status in children from Northeastern Brazil. This was a case-control study design. Stool samples were evaluated for hipO (C. jejuni), ask (C. coli), and cdtABC (C. jejuni's cytolethal distending toxin) genes. The nutritional status from these children was assessed by anthropometric measures and z-scores. C. jejuni and C. coli were detected in 9.6% (8/83) and 6.0% (5/83) in the diarrhea group and in 7.2% (6/83) and 1.2% (1/83) of the nondiarrhea group, respectively. Children with positive molecular detection of C. jejuni showed significantly lower z-scores than children without C. jejuni. The cdtABC operon was found in 57% of hipO(+) samples. C. jejuni/coli prevalence was similar in diarrhea and nondiarrhea groups. There was a significant association of C. jejuni infection with lower nutritional status.

Impact of the number of failed therapeutic regimes on the development of resistance mutations to HIV-1 in northeast Brazil.

Highly-potent antiretroviral therapy is necessary to avoid viral replication in HIV patients; however, it can favor the appearance of resistance mutations. The mutations 41L, 67N, 70R, 210W, 215Y/F, 219E/Q, 44D and 118I are defined as nucleoside analogous mutations (NAMs), because they affect the efficacy of all nucleoside reverse transcriptase inhibitors (NRTI). The mutation most frequently associated with non-nucleoside reverse transcriptase inhibitors (NNRTIs) is 103N. 33W/F, 82A/F/L/T, 84V and 90M are called protease inhibitor resistance-associated mutations (PRAM), because they are associated with resistance to several protease inhibitors (PI). This study evaluated the development of resistance mutations and examine the susceptibility of HIV with these mutations to antiretrovirals in HIV-1 patients who have failed one or more therapy regimes. Analyses were made of 101 genotypic tests of patients with therapeutic failure to 2 or 3-drug regimens with NRTI, NNRTI or PI. We used the Stanford database to define the susceptibility profile of the viruses. The samples were divided into three treatment-failure groups: first (F), second (S) and multi-failure (MF) to antiretroviral regimens, and we correlated these groups with resistance profiles and principal mutations. There was a significant increase in resistance mutations V82A/F/L/T, I84V, L90M, M41L, K70R, L210W, T215Y/F and K219Q/E in MF. We also found significantly higher resistance to zidovudine, didanosine, stavudine and abacavir in MF. There was no increase in resistance to tenofovir (p=0.28) and lopinavir (p=0.079) in MF. A high degree of resistance to NNRTIs was observed in all groups. Increased resistance mutations will affect future therapeutic options for HIV patients in Brazil because it results in a significant increase in resistance to antiretroviral drugs.

Impact of the number of failed therapeutic regimes on the development of resistance mutations to HIV-1 in northeast Brazil

Highly-potent antiretroviral therapy is necessary to avoid viral replication in HIV patients; however, it can favor the appearance of resistance mutations. The mutations 41L, 67N, 70R, 210W, 215Y/F, 219E/Q, 44D and 118I are defined as nucleoside analogous mutations (NAMs), because they affect the efficacy of all nucleoside reverse transcriptase inhibitors (NRTI). The mutation most frequently associated with non-nucleoside reverse transcriptase inhibitors (NNRTIs) is 103N. 33W/F, 82A/F/L/T, 84V and 90M are called protease inhibitor resistance-associated mutations (PRAM), because they are associated with resistance to several protease inhibitors (PI). This study evaluated the development of resistance mutations and examine the susceptibility of HIV with these mutations to antiretrovirals in HIV-1 patients who have failed one or more therapy regimes. Analyses were made of 101 genotypic tests of patients with therapeutic failure to 2 or 3-drug regimens with NRTI, NNRTI or PI. We used the Stanford database to define the susceptibility profile of the viruses. The samples were divided into three treatment-failure groups: first (F), second (S) and multi-failure (MF) to antiretroviral regimens, and we correlated these groups with resistance profiles and principal mutations. There was a significant increase in resistance mutations V82A/F/L/T, I84V, L90M, M41L, K70R, L210W, T215Y/F and K219Q/E in MF. We also found significantly higher resistance to zidovudine, didanosine, stavudine and abacavir in MF. There was no increase in resistance to tenofovir (p=0.28) and lopinavir (p=0.079) in MF. A high degree of resistance to NNRTIs was observed in all groups. Increased resistance mutations will affect future therapeutic options for HIV patients in Brazil because it results in a significant increase in resistance to antiretroviral drugs.

Genotype testing and antiretroviral resistance profiles from HIV-1 patients experiencing therapeutic failure in northeast Brazil.

Genotype testing for HIV-1 drug resistance is useful for selecting antiretroviral drug regimens for patients experiencing therapeutic failure, but the optimal means for interpreting the test results is unknown because many HIV-1 protease and reverse transcriptase (RT) mutations contribute to drug resistance. This study identified common combinations of resistance mutations related to antiretroviral resistance profiles. From April 2002 to March 2004, 101 protease and RT sequences were determined for HIV-1 isolates from patients who were failing antiretroviral therapy. The resistance profile was evaluated using the Stanford Database program. Male patients predominated (76.2%), the median age was 38 years, the average CD4 count was 279.21 cells/mm(3) and the average viral load was 4.49 log. In relation to protease inhibitors (IP) 31 mutation patterns were detected, 49 mutation patterns were detected in Nucleoside RT Inhibitors (NRTI), and 17 patterns were found in the Non Nucleoside RT Inhibitors (NNRTI). K65R was detected in 5.9% of the isolates. The most frequent mutations were: L90M, M184V and K103N related to PI's, NRTI's and NNRTI's, respectively. The best antiretroviral susceptibility was found to be Lopinavir in the PI class and Tenofovir in the NRTI class. The top six mutation patterns accounted for 49% of the resistance to PI's, for 38.5% of NRTI resistance, and the top two mutation patterns accounted for 40.9% of resistance to NNRTI's.

Genotype testing and antiretroviral resistance profiles from HIV-1 patients experiencing therapeutic failure in northeast Brazil

Genotype testing for HIV-1 drug resistance is useful for selecting antiretroviral drug regimens for patients experiencing therapeutic failure, but the optimal means for interpreting the test results is unknown because many HIV-1 protease and reverse transcriptase (RT) mutations contribute to drug resistance. This study identified common combinations of resistance mutations related to antiretroviral resistance profiles. From April 2002 to March 2004, 101 protease and RT sequences were determined for HIV-1 isolates from patients who were failing antiretroviral therapy. The resistance profile was evaluated using the Stanford Database program. Male patients predominated (76.2 percent), the median age was 38 years, the average CD4 count was 279.21 cells/mm³ and the average viral load was 4.49 log. In relation to protease inhibitors (IP) 31 mutation patterns were detected, 49 mutation patterns were detected in Nucleoside RT Inhibitors (NRTI), and 17 patterns were found in the Non Nucleoside RT Inhibitors (NNRTI). K65R was detected in 5.9 percent of the isolates. The most frequent mutations were: L90M, M184V and K103N related to PI's, NRTI's and NNRTI's, respectively. The best antiretroviral susceptibility was found to be Lopinavir in the PI class and Tenofovir in the NRTI class. The top six mutation patterns accounted for 49 percent of the resistance to PI's, for 38.5 percent of NRTI resistance, and the top two mutation patterns accounted for 40.9 percent of resistance to NNRTI's.