Chronic consumption of orange juice modifies urinary excretion of flavanone gut-derived metabolites through gut microbiota modulation

The metabolism and absorption of citrus flavanones are intrinsically linked to the gut microbiota, creating a bidirectional relationship where these compounds influence the microbiome, and in turn, the microbiota affects their metabolism. This study evaluates the effect of acute and chronic consumption of orange juice (OJ) on the urinary excretion of gut-derived flavanone metabolites and the gut microbiota. Health volunteers ingested 500 mL of OJ for 60 days in a single-arm human intervention study. Blood and feces were collected at baseline and after 60 days, with an additional 24-hour urine collection after a single dose on day 1 and day 63. LC-MS/MS analyzed urinary flavanone metabolites, while 16S rRNA sequencing characterized gut microbiota. Total urinary hesperetin conjugates excretion significantly decreased over 60 days, while gut-derived total phenolic acids, particularly three hydroxybenzoic acids, increased. Moreover, the heterogeneity of the total amount of flavanone conjugates, initially categorizing individuals into high-, medium- and low- urinary excretor profiles, shifted towards medium-excretor, except for five individuals who remained as low-excretors. This alteration was accompanied by a decrease in intestinal β-glucosidase activity and a shift in the relative abundance of specific genera, such as decreases in Blautia, Eubacterium hallii, Anaerostipes, and Fusicatenibacter, among which, Blautia was associated with higher urinary flavanone conjugates excretion. Conversely, an increase in Prevotella was observed. In summary, chronic OJ consumption induced transient changes in gut microbiota and altered the metabolism of citrus flavanones, leading to distinct urinary excretion profiles of flavanone metabolites.

Establishment of oral microbiome in very low birth weight infants during the first weeks of life and the impact of oral diet implementation

Very low birth weight (VLBW) infants, mostly preterm, have many barriers to feeding directly from the mother's breast, and need to be fed alternatively. Feeding is a major influencer in oral microbial colonization, and this colonization in early life is crucial for the promotion of human health. Therefore, this research aimed to observe the establishment of oral microbiome in VLBW infants during their first month of life through hospitalization, and to verify the impact caused by the implementation of oral diet on the colonization of these newborns. We included 23 newborns followed during hospitalization and analyzed saliva samples collected weekly, using 16S rRNA gene sequencing. We observed a significant decrease in richness and diversity and an increase in dominance over time (q-value < 0.05). The oral microbiome is highly dynamic during the first weeks of life, and beta diversity suggests a microbial succession in early life. The introduction of oral diet does not change the community structure, but affects the abundance, especially of Streptococcus. Our results indicate that although time is related to significant changes in the oral microbial profile, oral feeding benefits genera that will remain colonizers throughout the host's life.

Blood orange juice intake changes specific bacteria of gut microbiota associated with cardiometabolic biomarkers

Blood orange juice is an important source of flavanones and anthocyanins, mainly hesperidin, narirutin, and cyanidin-3-O-glucoside. The benefits of these bioactive compounds have been reported, but the mechanistic details behind their biological effects are not well established. This study investigated the effects of Moro orange (Citrus sinensis L. Osbeck) juice (MOJ) on gut microbiota composition and cardiometabolic biomarkers in overweight women. In this study, 12 overweight women (BMI from 25.0 to 29.9 kg/m²), aged 18-37 years, consumed 500 mL of MOJ every day for 4 weeks. We assessed the gut microbiota composition, levels of short-chain fatty acids (SCFAs), cardiometabolic biomarkers, and insulin resistance (HOMA-IR) at baseline and after 2 weeks and 4 weeks of MOJ intake. The results suggested that MOJ intake affected the abundance of specific operational taxonomic units (OTUs) of the gut microbiota but did not significantly alter the diversity and general composition of the gut microbiota. However, MOJ intake increased the production of SCFAs, especially propionic and isobutyric acids, and significantly improved cardiometabolic biomarkers such as blood pressure and plasma VCAM-1 levels in the overweight women. Additionally, we observed significant associations between gut microbiota OTUs belonging to the Bacteroidetes phyla and Prevotella 9 genera and the cardiometabolic biomarkers. Furthermore, MOJ reduced fasting glucose and insulin levels and HOMA-IR values, thereby enhancing insulin sensitivity in the insulin-resistant overweight women. Finally, we highlighted the importance of orange juice intake duration because some beneficial changes such as blood pressure improvements were evident at the 2-week time interval of the intervention, but other changes became significant only at the 4-week interval of MOJ intake. In conclusion, our study demonstrated that changes in specific OTUs of the gut microbiota in response to MOJ intake were associated with significant improvements in some cardiometabolic biomarkers and SCFA levels in overweight women with insulin resistance.

The gut microbiome of obese postpartum women with and without previous gestational diabetes mellitus and the gut microbiota of their babies

BACKGROUND

The incidence of gestational diabetes mellitus (GDM) is increasing worldwide, and has been associated with some changes in the gut microbiota. Studies have shown that the maternal gut microbiota pattern with hyperglycemia can be transmitted to the offspring. The study aimed to evaluate the gut microbiota of obese postpartum women with and without previous GDM and their offspring.

METHODS

We evaluated a total of 84 puerperal women who had (n = 40) or not GDM (n = 44), and their infants were also included. Stool samples were obtained 2-6 months after delivery. The molecular profile of the fecal microbiota was obtained by sequencing V4 region of 16S rRNA gene (Illumina^® MiSeq).

RESULTS

We found that the gut microbiota structures of the puerperal women and their infants were similar. Stratifying according to the type of delivery, the relative abundance of Victivallis genus was higher in women who had natural delivery. Exposure to exclusive breastfeeding was associated with a greater abundance of Bacteroides and Staphylococcus. The differential abundance test showed correlations to clinical and laboratory parameters. This work showed no difference in the microbiota of obese puerperal women with and without GDM and their offspring. However, breastfeeding contributed to the ecological succession of the intestinal microbiota of the offspring.

CONCLUSION

This work can contribute to understanding the potential effects of GDM and early life events on the gut microbiome of mothers and their offspring and its possible role in metabolism later in life.

Gut Microbiota across Normal Gestation and Gestational Diabetes Mellitus: A Cohort Analysis

The prevalence of gestational diabetes mellitus (GDM) is a global public health concern. The mechanism that leads to glucose tolerance beyond normal physiological levels to pathogenic conditions remains incompletely understood, and it is speculated that the maternal microbiome may play an important role. This study analyzes the gut microbiota composition in each trimester of weight-matched women with and without GDM and examines possible bacterial genera associations with GDM. This study followed 56 pregnant women with GDM and 59 without admitted to the outpatient clinic during their first/second or third trimester of gestation. They were submitted to a standardized questionnaire, dietary recalls, clinical examination, biological sample collection, and molecular profiling of fecal microbiota. Women with GDM were older and had a higher number of pregnancies than normal-tolerant ones. There was no difference in alpha diversity, and the groups did not differ regarding the overall microbiota structure. A higher abundance of Bacteroides in the GDM group was found. A positive correlation between Christensenellaceae and Intestinobacter abundances with one-hour post-challenge plasma glucose and a negative correlation between Enterococcus and two-hour plasma glucose levels were observed. Bifidobacterium and Peptococcus abundances were increased in the third gestational trimester for both groups. The gut microbiota composition was not dependent on the presence of GDM weight-matched women throughout gestation. However, some genera abundances showed associations with glucose metabolism. Our findings may therefore encourage a deeper understanding of physiological and pathophysiological changes in the microbiota throughout pregnancy, which could have further implications for diseases prevention.

Impact of Oropharyngeal Administration of Colostrum in Preterm Newborns' Oral Microbiome

The initial colonization of the human microbiota is of paramount importance. In this context, the oropharyngeal administration of colostrum is a safe, viable, and well-tolerated practice even by the smallest preterm infants. Therefore, this study evaluated the effects of oropharyngeal administration of colostrum on the establishment of preterm infants' oral microbiota. A longitudinal observational study was carried out with 20 premature neonates, divided into two groups: one receiving the protocol (Oropharyngeal Administration of Colostrum; OAC) and the other one receiving Standard Caare (SC). Saliva samples were collected from the newborns weekly during the study period (from the day of birth until the 21st day of life) for analysis of oral microbiota through 16S rRNA gene sequencing. We observed that the colonization of the oral microbiota of preterm newborns preseanted a higher relative abundance of Staphylococcus on the 7th day of life, mainly in the OAC group. Additionally, an increased abundance of Bifidobacterium and Bacteroides was observed in the OAC group at the first week of life. Regarding alpha and beta diversity, time was a key factor in the oral modulation of both groups, showing how dynamic this environment is in early life.

Saccharomyces boulardii modulates oxidative stress and renin angiotensin system attenuating diabetes-induced liver injury in mice

Type 1 diabetes (T1DM) is a chronic disease characterized by hyperglycemia due to a deficiency in endogenous insulin production, resulting from pancreatic beta cell death. Persistent hyperglycemia leads to enhanced oxidative stress and liver injury. Several studies have evaluated the anti-diabetic and protective effects of probiotic strains in animal models. In the present study, we investigated, through histopathological and biochemical analyses, the effects of eight weeks of administration of Saccharomyces boulardii (S. boulardii) yeast on the liver of streptozotocin (STZ) induced diabetic C57BL/6 mice. Our results demonstrated that S. boulardii attenuates hepatocytes hydropic degeneration and hepatic vessels congestion in STZ-induced diabetic mice. The treatment attenuated the oxidative stress in diabetic mice leading to a reduction of carbonylated protein concentration and increased activity of antioxidant enzymes superoxide dismutase and glutathione peroxidase, compared to untreated diabetic animals. The results also show the beneficial influence of S. boulardii in regulating the hepatic concentration of renin angiotensin system (RAS) peptides. Therefore, our results demonstrated that S. boulardii administration to STZ-induced diabetic mice reduces oxidative stress and normalizes the concentration of RAS peptides, supporting the hypothesis that this yeast may have a role as a potential adjunctive therapy to attenuate diabetes-induced liver injury.

Gut microbiota comparison of vaginally and cesarean born infants exclusively breastfed by mothers secreting α1-2 fucosylated oligosaccharides in breast milk

BACKGROUND

Exclusive breastfeeding promotes beneficial modifications on the microbiota of cesarean born infants, but little is known about the role of specific breast milk components in this modulation. Women with an active FUT2 gene (called secretors) secrete α1-2 fucosylated human milk oligosaccharides (HMOs), which promote Bifidobacterium in the infant's gut and may modulate the microbiota of cesarean born infants.

OBJECTIVE

To compare the microbiota composition of cesarean and vaginally born infants breastfed by secretor mothers.

METHODS

Maternal secretor status was determined by the occurrence of 4 different α1-2 fucosylated HMOs in breast milk by LC-MS. The fecal microbiota composition from cesarean and vaginally born infants was analyzed by 16S rRNA gene sequencing and qPCR, stratified by the maternal secretor status, and compared.

RESULTS

Alpha and beta diversity were not significantly different in cesarean born, secretor-fed infants (CSe+) compared to vaginally born, secretor-fed infants (VSe+). There were no significant differences in the fecal relative abundance of Bifidobacterium between CSe+ and VSe+ infants, but the prevalence of the species B. longum was lower in CSe+. The fecal relative abundance of Bacteroides was also lower, while Akkermansia and Kluyvera were higher in CSe+ infants.

CONCLUSION

Cesarean and vaginally born infants fed with breast milk containing the α1-2 fucosylated HMOs fraction present similar amounts of Bifidobacterium in the feces, but differences are observed in other members of the microbiota.

Gut Microbiome of Children and Adolescents With Primary Sclerosing Cholangitis in Association With Ulcerative Colitis

Few studies reported the relation of intestinal microbiome composition and diversity in pediatric patients with primary sclerosing cholangitis (PSC) and ulcerative colitis (UC). In this cross-sectional study, we selected patients younger than 19 years old from the pediatric gastroenterology and hepatology outpatient clinic of a tertiary hospital to describe the intestinal microbiome of pediatric patients with PSC associated or not to UC. Patients were divided in PSC, PSC+UC, and UC diagnosis. A stool sample was collected from each patient (n=30) and from a healthy relative/neighbor (n=23). The microbiome composition was assessed using MiSeq (Illumina) platform. Differences in microbial composition were found between PSC and PSC+UC groups. The relative abundance of Veillonella and Megasphaera genera were increased depending on patients’ age at diagnosis. Veillonella was also increased in patients who were in an active status of the disease. Both genera were positively correlated to total bilirubin and gamma-glutamyl transferase. As a conclusion, the disease, the age and the disease activity status seem to influence the intestinal microbiome, highlighting the difference of intestinal microbiome profile for patients depending on age at diagnosis. We also showed an increase of Veillonella in patients with PSC and PSC+UC, and a positive correlation of dysbiosis and higher gamma-glutamyl transferase and total bilirubin in PSC+UC patients. Our findings are promising in the diagnosis, prognosis, and future therapeutic perspectives for PSC patients.

Women's multisite microbial modulation during pregnancy

The composition of female microbiome varies with age, physiological and socio-behavior conditions. Also, changes in microbiome composition are observed as pregnancy progresses, especially in the vaginal site. Together with the physiological adaptations of gestation, changes in microbiome composition seem to be fundamental for proper fetal development. This study aimed at simultaneously evaluating the vaginal, gut, and oral microbiome of healthy pregnant women, and comparing it with those observed in healthy non-pregnant women of reproductive age. In a cross-sectional study, vaginal, oral and gut samples were collected from 42 pregnant and 18 non-pregnant women, and the microbiome composition was evaluated by 16S rRNA sequencing, using Illumina platform. In the pregnant group, we observed a positive correlation between Eubacterium and Akkermansia in the gut samples; between Eubacterium and Ruminococcus in the vaginal samples; and between Streptococcus and Gemella in the oral samples. Notwithstanding, we observed a negative correlation between Lactobacillus and Atopobium and between Lactobacillus and Gardnerella in vaginal microbiome. Prevotella was the only genus found in all three sites studied; however, there was no signal of bacterial influence between sites during pregnancy. These results suggest that in addition to hormonal and immunological variations during healthy pregnancy, the female body also undergoes microbiome modulation in multiple sites in order to maintain an eubiotic status.

Saccharomyces boulardii Tht 500101 changes gut microbiota and ameliorates hyperglycaemia, dyslipidaemia, and liver inflammation in streptozotocin-diabetic mice

Type 1 diabetes mellitus (T1DM) is a disorder resulting from chronic autoimmune destruction of insulin-producing pancreatic β-cells, lack of insulin production and hyperglycaemia. The aim of this study was to evaluate the hypothesis that streptozotocin-diabetic mice treated with Saccharomyces boulardii THT 500101 strain present improvement of glucose and triglycerides metabolism, reduction of liver inflammation concomitant with a beneficial impact in the gut microbiota profile. C57BL/6 male mice were randomly assigned into three groups: Control, Diabetes, Diabetes+Probiotic, and were euthanised 8 weeks after probiotic chronic administration. Mice submitted to treatment presented reduced glycemia in comparison with the diabetic group, which was correlated with an increase in C-peptide level and in hepatic glycogen content. Fat metabolism was significantly altered in streptozotocin-induced diabetic group, and S. boulardii treatment regulated it, leading to a decrease in serum triglycerides secretion, increase in hepatic triglycerides storage and modulation of inflammatory profile. The phenotypic changes seen from chronic S. boulardii treatment were found to be broadly associated with the changes in microbioma of diabetic animals, with increased proportion in Bacteroidetes, Firmicutes and Deferribacteres, and a decreased proportion of Proteobacteria and Verrucomicrobia phylum. Thus, the data presented here show up a novel potential therapeutic role of S. boulardii for the treatment and attenuation of diabetes-induced complications.

Microbiome and its relation to gestational diabetes

PURPOSE

Gestational diabetes mellitus (GDM), the major endocrine pathology in pregnancy, has been associated with the development of an intense inflammatory process and increased insulin resistance. The maternal microbiota is involved in several metabolic functions; however, its role in GDM physiopathology remains unclear. The aim of this study was to assess the composition of the microbiota at different sites and evaluate its relationship with the occurrence of GDM.

METHODS

This cross-sectional study recruited women in the third trimester of gestation with and without GDM. Oral, vaginal, and stool samples were evaluated using next-generation sequencing. We included 68 participants: 26 with and 42 without GDM.

RESULTS

The analysis of the oral microbiome did not show significant differences in phyla and genus among the studied groups. In contrast, GDM patients presented a specific vaginal and intestinal microbiome composition, which was less diverse than those found in the control group, showing genera related to dysbiosis.

CONCLUSIONS

Our findings suggest that changes in the composition of the vaginal and intestinal microbiome might be involved in the development of GDM. The follow-up of these patients in order to evaluate vaginal and intestinal samples after delivery may contribute to understanding the development of metabolic disease in women with previous GDM.

Breastfeeding increases microbial community resilience

OBJECTIVE

Since the present group had already described the composition of the intestinal microbiota of Brazilian infants under low social economic level, the aim of the present study was to analyze the microbial community structure changes in this group of infants during their early life due to external factors.

METHODS

Fecal samples were collected from 11 infants monthly during the first year of life. The infants were followed regarding clinical and diet information and characterized according to breastfeeding practices. DNA was extracted from fecal samples of each child and subjected to Polymerase Chain Reaction - Denaturing Gradient Gel Electrophoresis.

RESULTS

The results revealed a pattern of similarity between the time points for those who were on exclusive breastfeeding or predominant breastfeeding. Although there were changes in intensity and fluctuation of some bands, the Denaturing Gradient Gel Electrophoresis patterns in the one-year microbial analysis were stable for breastfeeding children. There was uninterrupted ecological succession despite the influence of external factors, such as complementary feeding and antibiotic administration, suggesting microbiota resilience. This was not observed for those children who had mixed feeding and introduction of solid food before the 5^th month of life.

CONCLUSION

These results suggested an intestinal microbiota pattern resilient to external forces, due to the probiotic and prebiotic effects of exclusive breastfeeding, reinforcing the importance of exclusive breastfeeding until the 6^th month of life.

Anaerobic bacteria in the intestinal microbiota of Brazilian children

OBJECTIVE:

Changes in the neonatal gut environment allow for the colonization of the mucin layer and lumen by anaerobic bacteria. The aim of the present study was to evaluate Bifidobacterium, Lactobacillus and Lactococcus colonization through the first year of life in a group of 12 Brazilian infants and to correlate these data with the levels of Escherichia coli. The presence of anaerobic members of the adult intestinal microbiota, including Eubacterium limosum and Faecalibacterium prausnitzii, was also evaluated.

METHODS:

Fecal samples were collected during the first year of life, and 16S rRNA from anaerobic and facultative bacteria was detected by real-time PCR.

RESULTS:

Bifidobacterium was present at the highest levels at all of the studied time points, followed by E. coli and Lactobacillus. E. limosum was rarely detected, and F. prausnitzii was detected only in the samples from the latest time points.

CONCLUSION:

These results are consistent with reports throughout the world on the community structure of the intestinal microbiota in infants fed a milk diet. Our findings also provide evidence for the influence of the environment on intestinal colonization due to the high abundance of E. coli. The presence of important anaerobic genera was observed in Brazilian infants living at a low socioeconomic level, a result that has already been well established for infants living in developed countries.

Microbiome, growth retardation and metabolism: are they related?

CONTEXT

Despite an improvement in food security and the delivery of nutritional supplements to children living in impoverished parts of the world, poor growth is still highly prevalent. Given that the microbiome is related to both nutrient absorption, as well as overweight/obesity, it may play a central role in limiting or modifying normal growth processes while contributing to chronic disease risks.

OBJECTIVE

The objective of this paper is to describe normal growth processes, the role of the microbiome in supporting or disrupting normal growth processes, and its potential impact on long-term health.

METHODS

A literature search of relevant human and laboratory research on growth, microbiome and the relationship between poor growth and chronic diseases was conducted. This review focuses on potential mechanisms that implicate the microbiome as a mediator of poor growth and later metabolic outcomes. In this relationship, attention was given to the potential for gastrointestinal infections to disrupt the microbiome.

RESULTS

Based on the studies reviewed, it is clear that exposure to infections disturbs both intestinal functioning as well as normal growth and changes in the microbiome may influence micronutrient availability and metabolic processes.

CONCLUSIONS

The microbiome may play a significant role in limiting human growth, but little is known about changes in the microbiome during periods of undernutrition. Thus, it is of great scientific and public health importance to improve the understanding of how the microbiome changes during nutrient deprivation. To best address the issue of the double burden and poor growth in low-income countries, research is warranted to advance the knowledge of the long-term role of the microbiome in the health of children exposed to undernutrition.

High abundance of Escherichia during the establishment of fecal microbiota in Brazilian children

The sequence of bacterial events that occurs during the colonization of the gastrointestinal tract may affect the future health of the host. A clear understanding of the colonization process of the human neonatal gut in developing countries is lacking because the few available studies were mostly performed using culture techniques. Using molecular approaches, this study analyzed the fecal microbiota of children of low socioeconomic status in São Paulo, Brazil, during their first year of life. We collected fecal samples of healthy children at 3, 6, and 12 months of life. Total DNA was extracted directly from feces, and the bacteria-specific primers 27F-1492R were used to construct 16S rRNA libraries. Clones were randomly selected and partially sequenced. The main phylogenetic groups identified at 3 months were Streptococcus, unidentified bacteria, and Escherichia. At 6 months, Escherichia remained predominant, while the unidentified bacterial population increased significantly. At 12 months, a more complex composition of fecal microbiota was observed, represented by unidentified bacteria and microorganisms found at low rates at earlier ages. The genus Escherichia remained the most abundant microorganism (34% relative abundance and 75% prevalence). Principal component analysis (PCA) revealed changes in the composition of the microbiota at 6 months and an increase of diversity at 12 months of life. Bifidobacterium was identified by quantitative PCR (qPCR) and showed a high incidence in the microbiota at 3 months. The present results corroborate the global observation of inter-individual variability with an early establishment of microbial complexity at the end of the first year of life and highlight the presence of the Escherichia as abundant in microbiota composition of this group of children.

Establishment of the bacterial fecal community during the first month of life in Brazilian newborns

OBJECTIVE

The establishment of the intestinal microbiota in newborns is a critical period with possible long-term consequences for human health. In this research, the development of the fecal microbiota of a group of exclusively breastfed neonates living in low socio-economic conditions in the city of São Paulo, Brazil, during the first month of life, was studied.

METHODS

Fecal samples were collected from ten neonates on the second, seventh, and 30(th) days after birth. One of the neonates underwent antibiotic therapy. Molecular techniques were used for analysis; DNA was extracted from the samples, and 16S rRNA libraries were sequenced and phylogenetically analyzed after construction. A real-time polymerase chain reaction (PCR) was performed on the samples taken from the 30(th) day to amplify DNA from Bifidobacterium sp.

RESULTS

The primary phylogenetic groups identified in the samples were Escherichia and Clostridium. Staphylococcus was identified at a low rate. Bifidobacterium sp. was detected in all of the samples collected on the 30(th) day. In the child who received antibiotics, a reduction in anaerobes and Escherichia, which was associated with an overgrowth of Klebsiella, was observed throughout the experimental period.

CONCLUSION

The observed pattern of Escherichia predominance and reduced Staphylococcus colonization is in contrast with the patterns observed in neonates living in developed countries.

A Comparative Study of the Outer Membrane Proteome from an Atypical and a Typical Enteropathogenic Escherichia coli

This study compared the proteomic profile of outer membrane proteins (OMPs) from one strain of atypical enteropathogenic Escherichia coli (aEPEC) and one of typical EPEC (tEPEC). The OMPs fractions were obtained using sarcosine extraction, and analyzed by one- and two-dimensional gel electrophoresis (1DE and 2DE, respectively). The 1DE OMPs analysis of typical and atypical EPEC evidenced similar patterns; however, the 2DE OMP profile from the aEPEC revealed more protein spots in the 40- to 70-kDa region. 2DE image analysis identified 159 protein spots in both strains whereas 53 protein spots were observed only in tEPEC and 128 were observed only in aEPEC. Remarkably, 41.5% of aEPEC spots showed higher levels of expression compared to tEPEC, some of which with two, others four or even five times more. Twenty-four selected spots were identified using MALDI-TOF mass spectrometry and they corresponded to proteins involved in cell structure and metabolism, as well as in gene regulation. Some of these proteins showed similarity with proteins identified in other E. coli pathotypes. Besides, the differential expression of some proteins in aEPEC may suggest that it could be related to their features that ascertain the adaptation to distinct environments and the worldwide spread distribution of these pathogens.

Secreted autotransporter toxin produced by a diffusely adhering Escherichia coli strain causes intestinal damage in animal model assays

Bacterial diarrheal diseases remain a major cause of morbidity and mortality in developing countries. Diffusely adhering Escherichia coli (DAEC) is a newly proposed category of diarrheagenic E. coli based on epidemiological studies. Sat, a new virulence factor of some uropathogeic Escherichia coli, was described with a vacuolating cytotoxic action in bladder and kidney tissues. In the present study, we analyzed the Sat effects, produced by a DAEC strain in rabbit ileal intestinal tissue and cultured epithelial cells. We observed enterotoxic activity in rabbit ileum tissues by Ussing chamber assays, a pronounced fluid accumulation in rabbit ileum loops with villous necrosis observed in the histopathologic examination, and morphological changes in monolayer cultures of Y1 adrenal cells. Our results suggest that DAEC strains may be involved in diarrhea.

Antibody response against plasmid-encoded toxin (Pet) and the protein involved in intestinal colonization (Pic) in children with diarrhea produced by enteroaggregative Escherichia coli

Enteroaggregative Escherichia coli (EAEC) is an emerging cause of pediatric and adult travellers diarrhea. The mechanism by which EAEC induce diarrhea is not completely known. Two serine protease autotransporter proteins, named Pet and Pic have been identified in EAEC strains. Pet has enterotoxic and cytotoxic activities, while the role of Pic in pathogenesis may lie on its mucinolytic activity. Little is known about Pet and Pic biological activities in vivo. In this study the antibody responses against these autotransporter proteins in convalescent children is investigated. Fifteen (83%) children showed specific antibodies against Pet or Pic in their sera. IgG and IgM antibodies were the main isotype found. Specific antibodies against Pic, but not against Pet, were detected in sera from age-matched control group. These data show that specific anti-Pet and anti-Pic antibodies are produced during the course of a natural EAEC infection in children.

Prevalence of secreted autotransporter toxin gene among diffusely adheringEscherichia coliisolated from stools of children

In this report, we analyzed the prevalence of the sat gene in 336 Escherichia coli samples collected from stools of children with and without diarrhea in Brazil and in 100 uropathogenic E. coli strains. The results show a high correlation between diffusely adhering E. coli (DAEC) and the presence of sat (44%) in intestinal isolates. DAEC strain FBC114 expresses a 107-kDa protein, which showed 98% homology with Sat.

[Etiologic profile of acute diarrhea in children in São Paulo]

OBJECTIVE: To evaluate the etiologic profile of acute diarrhea in socioeconomically deprived children assisted at a regional pediatric emergency care service. METHODS: During two years all children with acute diarrhea assisted at a previously established day and week time schedule were included in the study. Other selective criteria were: a) age less than 5 years; b) nonuse of antibiotics in the previous month; and c) no travel outside the city in the previous month. Stool examination was used for the detection of the following microorganisms: a) rotavirus (immunofluorescence and counterimmunoelectrophoresis); b) bacteria - culture in MacConkey agar, SS agar, Columbia agar, bright green, serotyping, detection of toxins - INV, LT,ST,SLT I, SLT II, Sereny test, detection of virulence factors- EAF, eae, BFP; and c) protozoa (Hoffman and Faust). In the same period, a control group without diarrhea was also evaluated for the same fecal pathogens. RESULTS: Between March 1994 and June 1996, 154 children with acute diarrhea (AD) and 42 control children (WAD), that is, without acute diarrhea, were selected. In the AD group, intestinal pathogens were detected in 112 (72.8%) cases, and in 9 (21.5%) cases in the WAD group. The association of two or more intestinal pathogens occurred in 47 (30.5%) cases in the AD group, and in 3 (7.1%) cases in the WAD group. The pathogens identified in the AD cases were: Rotavirus: 32 (20.8%), bacteria: 53 (34.4%), both: 25 (16.2%), and 2 (1.4%) with Giardia lamblia (in one case associated with Rotavirus and in another one associated with bacteria). In the WAD group, only bacteria were detected in 8 (19.1%) cases, and bacteria associated with Giardia lamblia in 1 (2.4%) case. Altogether, there were 105 bacteria isolated in the AD group: 90 were Escherichia coli (EPEC 27, DAEC 24, ETEC 21, EAEC 18), 12 were Shigella sp, 2 were Salmonella sp, and one was Yersinia sp. Children with mixed infections (viral and bacterial) had increased incidence of severe vomiting, dehydration and hospitalization. CONCLUSIONS: Bacteria were the most frequent pathogens detected in acute diarrhea cases, among which Escherichia coli was highly predominant. The majority of Escherichia coli strains belong to non-EPEC varieties, strains that are not routinely evaluated in clinical laboratories of pathology. Rotavirus was found in a great number of diarrhea cases, often associated with bacteria. Protozoa showed reduced importance.

Antibody response of children with enteropathogenic Escherichia coli infection to the bundle-forming pilus and locus of enterocyte effacement-encoded virulence determinants

Enteropathogenic Escherichia coli (EPEC) express a plasmid-encoded type IV pilus termed bundle-forming pilus, which is associated with the formation of bacterial microcolonies on cultured epithelial cells. Bacterial attachment and effacement of the enterocyte brush border membrane is attributed to a surface outer membrane protein adhesin termed intimin and EPEC-secreted proteins EspA, EspB, and EspD. Except for intimin, production in vivo or antibody response against these virulence determinants during natural EPEC infections in young children has not been demonstrated. Antibody responses against BfpA, intimin, EspA, and EspB were investigated in Brazilian children naturally infected with EPEC. Generally, IgG antibodies against BfpA and EspB were the most commonly found, followed by anti-EspA and intimin antibodies. Thus, bundle-forming pilus and locus of enterocyte attachment-encoded products are produced in vivo during natural EPEC infections and elicit an immune response against heterologous EPEC virulence determinants. These findings have important implications in the immunoprophylaxis against EPEC infections.

Compatibility and stability of labetalol hydrochloride in commonly used intravenous solutions

Compatibility and stability of labetalol hydrochloride when mixed with commonly used large-volume parenterals (LVPs) were tested. Labetalol hydrochloride injection was added to 11 LVPs at concentrations of 1.25, 2.50, and 3.75 mg/ml. After initial samples were obtained, the admixtures were divided equally and stored for 72 hours at 4 degrees C and 25 degrees C. The initial samples and aliquots withdrawn at 6, 24, and 72 hours were frozen until analysis. The initial and 72-hour samples were analyzed for drug concentration, pH, osmolarity, and visual changes. High-performance liquid chromatography (HPLC) was used for the assay, and the American Public Health Association color-testing procedure was used in evaluating color. In the admixture with 5% sodium bicarbonate injection, a white precipitate formed within six hours. At both storage temperatures, the drug concentration in all other LVP solutions was not appreciably different from the initial concentration. No additional HPLC peaks were noted, and no measurable change in pH or osmolarity occurred. No haze, precipitate, or color change occurred in the 10 admixtures. Labetalol hydrochloride was stable for 72 hours at 4 degrees C and 25 degrees C in all i.v. solutions studied except 5% sodium bicarbonate injection.

High performance liquid chromatographic determination of clotrimazole in pharmaceutical formulations

A simple stability-indicating high performance liquid chromatographic (HPLC) method has been developed which separates clotrimazole from impurities and decomposition products in bulk drugs, creams, tablets, and solutions. Average recovery data for drug substance added to placebos were: tablet, 99.8%; solution, 99.5%; and cream, 100.0%. Average reproducibilities (RSD) on drug substance and formulations were: drug substance, 1.3%; tablets, 1.8%; solutions, 1.1%; and creams, 0.6%. HPLC assay results for both fresh and degraded samples agree with USP XX titration assay results. The method allows for the simultaneous determination of (o-chlorophenyl)diphenylmethanol hydrolysis product impurity.