Sexually dimorphic response of mice to the Western-style diet caused by deficiency of fatty acid binding protein 6 (Fabp6)

Bile acids are natural detergents that aid in the absorption of dietary lipids. Fatty acid binding protein 6 (Fabp6) is a component of the bile acid recovery system that operates in the small intestine. The aim of this study was to determine if Fabp6 deficiency causes dietary fat malabsorption. Wild-type and Fabp6-deficient mice were fed a Western-style diet (WSD) or a reference low-fat diet (LFD) for 10 weeks. The body weight gain, bile acid excretion, fat excretion, energy metabolism, and major gut microbial phyla of the mice were assessed at the end of the controlled diet period. Fabp6-/- mice exhibited enhanced excretion of both bile acids and fat on the WSD but not on the LFD diet. Paradoxically, male Fabp6-/- mice, but not female Fabp6-/- mice, had greater adiposity despite increased fat excretion. Analysis of energy intake and of expenditure by indirect calorimetry revealed sex differences in physical activity level and respiratory quotient, but these did not account for the enhanced adiposity displayed by male Fabp6-/- mice. Analysis of stool DNA showed sex-specific changes in the abundance of major phyla of bacteria in response to Fabp6 deficiency and WSD feeding. The results obtained indicate that the malabsorption of bile acids that occurs in Fabp6-/- mice is associated with dietary fat malabsorption on the high-fat diet but not on the low-fat diet. The WSD induced a sexually dimorphic increase in adiposity displayed by Fabp6-/- mice and sexually distinct pattern of change in gut microbiota composition.

Animal Models of Undernutrition and Enteropathy as Tools for Assessment of Nutritional Intervention

: Undernutrition is a major public health problem leading to 1 in 5 of all deaths in children under 5 years. Undernutrition leads to growth stunting and/or wasting and is often associated with environmental enteric dysfunction (EED). EED mechanisms leading to growth failure include intestinal hyperpermeability, villus blunting, malabsorption and gut inflammation. As non-invasive methods for investigating gut function in undernourished children are limited, pre-clinical models are relevant to elucidating the pathophysiological processes involved in undernutrition and EED, and to identifying novel therapeutic strategies. In many published models, undernutrition was induced using protein or micronutrient deficient diets, but these experimental models were not associated with EED. Enteropathy models mainly used gastrointestinal injury triggers. These models are presented in this review. We found only a few studies investigating the combination of undernutrition and enteropathy. This highlights the need for further developments to establish an experimental model reproducing the impact of undernutrition and enteropathy on growth, intestinal hyperpermeability and inflammation, that could be suitable for preclinical evaluation of innovative therapeutic intervention.

Pathobiome driven gut inflammation in Pakistani children with Environmental Enteric Dysfunction

Environmental Enteric Dysfunction (EED) is an acquired small intestinal inflammatory condition underlying high rates of stunting in children <5 years of age in low- and middle-income countries. Children with EED are known to have repeated exposures to enteropathogens and environmental toxins that leads to malabsorptive syndrome. We aimed to characterize association of linear growth faltering with enteropathogen burden and subsequent changes in EED biomarkers. In a longitudinal birth cohort (n = 272), monthly anthropometric measurements (Length for Age Z score- LAZ) of asymptomatic children were obtained up to 18 months. Biological samples were collected at 6 and 9 months for the assessment of biomarkers. A customized TaqMan array card was used to target 40 enteropathogens in fecal samples. Linear regression was applied to study the effect of specific enteropathogen infection on change in linear growth (ΔLAZ). Presence of any pathogen in fecal sample correlated with serum flagellin IgA (6 mo, r = 0.19, p = 0.002), fecal Reg 1b (6 mo, r = 0.16, p = 0.01; 9mo, r = 0.16, p = 0.008) and serum Reg 1b (6 mo, r = 0.26, p<0.0001; 9 mo, r = 0.15, p = 0.008). At 6 months, presence of Campylobacter [β (SE) 7751.2 (2608.5), p = 0.003] and ETEC LT [β (SE) 7089.2 (3015.04), p = 0.019] was associated with increase in MPO. Giardia was associated with increase in Reg1b [β (SE) 72.189 (26.394), p = 0.006] and anti-flic IgA[β (SE) 0.054 (0.021), p = 0.0091]. Multiple enteropathogen infections in early life negatively correlated with ΔLAZ, and simultaneous changes in gut inflammatory and permeability markers. A combination vaccine targeting enteropathogens in early life could help in the prevention of future stunting.

CVID enteropathy is characterized by exceeding low mucosal IgA levels and interferon-driven inflammation possibly related to the presence of a pathobiont

Common variable immunodeficiency (CVID), the most common symptomatic primary antibody deficiency, is accompanied in some patients by a duodenal inflammation and malabsorption syndrome known as CVID enteropathy (E-CVID).The goal of this study was to investigate the immunological abnormalities in CVID patients that lead to enteropathy as well as the contribution of intestinal microbiota to this process.We found that, in contrast to noE-CVID patients (without enteropathy), E-CVID patients have exceedingly low levels of IgA in duodenal tissues. In addition, using transkingdom network analysis of the duodenal microbiome, we identified Acinetobacter baumannii as a candidate pathobiont in E-CVID. Finally, we found that E-CVID patients exhibit a pronounced activation of immune genes and down-regulation of epithelial lipid metabolism genes. We conclude that in the virtual absence of mucosal IgA, pathobionts such as A. baumannii, may induce inflammation that re-directs intestinal molecular pathways from lipid metabolism to immune processes responsible for enteropathy.

The prevalence of small intestinal bacterial overgrowth in non-surgical patients with chronic pancreatitis and pancreatic exocrine insufficiency (PEI)

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is a condition characterised by symptoms similar to pancreatic exocrine insufficiency (PEI) in chronic pancreatitis patients. SIBO is thought to complicate chronic pancreatitis in up to 92% of cases; however, studies are heterogeneous and protocols non-standardised. SIBO may be determined by measuring lung air-expiration of either hydrogen or methane which are by-products of small bowel bacterial fermentation of intraluminal substrates such as carbohydrates. We evaluated the prevalence of SIBO among a defined cohort of non-surgical chronic pancreatitics with mild to severe PEI compared with matched healthy controls.

METHODS

Thirty-five patients and 31 age-, gender- and smoking status-matched healthy controls were evaluated for SIBO by means of a fasting glucose hydrogen breath test (GHBT). The relationship between SIBO and clinical symptoms in chronic pancreatitis was evaluated.

RESULTS

SIBO was present in 15% of chronic pancreatitis patients, while no healthy controls tested positive (P = 0.029). SIBO was more prevalent in those taking pancreatic enzyme replacement therapy (PERT) (P = 0.016), with proton pump inhibitor use (PPI) (P = 0.022) and in those with alcohol aetiology (P = 0.023). Patients with concurrent diabetes were more often SIBO-positive and this was statistically significant (P = 0.009). There were no statistically significant differences in reported symptoms between patients with and without SIBO, with the exception of 'weight loss', with patients reporting weight loss more likely to have SIBO (P = 0.047).

CONCLUSION

The prevalence of SIBO in this study was almost 15% and consistent with other studies of SIBO in non-surgical chronic pancreatitis patients. These data support the testing of patients with clinically-relevant PEI unresolved by adequate doses of PERT, particularly in those patients with concurrent diabetes. SIBO can be easily diagnosed therefore allowing more specific and more targeted symptom treatment.

Small Intestinal Bacterial Overgrowth: Nutritional Implications, Diagnosis, and Management

Small intestinal bacterial overgrowth (SIBO), characterized by the presence of excessive bacteria in the small intestine, is typically described as a malabsorptive syndrome occurring in the context of gut stasis syndromes. SIBO is now considered to be a disorder associated with diverse clinical conditions without classic risk factors for SIBO and a cause of several nonspecific gastrointestinal and nongastrointestinal symptoms. Because there is currently no gold standard for diagnosing SIBO, its prevalence and role in the pathogenesis of other diseases remain uncertain; as does optimal treatment of patients with relapsing symptoms.

Dietary Carbohydrates and Childhood Functional Abdominal Pain

Childhood functional gastrointestinal disorders (FGIDs) affect a large number of children throughout the world. Carbohydrates (which provide the majority of calories consumed in the Western diet) have been implicated both as culprits for the etiology of symptoms and as potential therapeutic agents (e.g., fiber) in childhood FGIDs. In this review, we detail how carbohydrate malabsorption may cause gastrointestinal symptoms (e.g., bloating) via the physiologic effects of both increased osmotic activity and increased gas production from bacterial fermentation. Several factors may play a role, including: (1) the amount of carbohydrate ingested; (2) whether ingestion is accompanied by a meal or other food; (3) the rate of gastric emptying (how quickly the meal enters the small intestine); (4) small intestinal transit time (the time it takes for a meal to enter the large intestine after first entering the small intestine); (5) whether the meal contains bacteria with enzymes capable of breaking down the carbohydrate; (6) colonic bacterial adaptation to one's diet, and (7) host factors such as the presence or absence of visceral hypersensitivity. By detailing controlled and uncontrolled trials, we describe how there is a general lack of strong evidence supporting restriction of individual carbohydrates (e.g., lactose, fructose) for childhood FGIDs. We review emerging evidence suggesting that a more comprehensive restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) may be effective. Finally, we review how soluble fiber (a complex carbohydrate) supplementation via randomized controlled intervention trials in childhood functional gastrointestinal disorders has demonstrated efficacy.

[Digestive enzyme functionality in pathology of the gastrointestinal tract with intestinal microbiocenosis disorders]

A change pattern in enzyme release function of digestive glands exerts the organism as a whole. Dysfunctions of hydrolysis and intestinal malabsorption (secondary malabsorption syndrome) are the first step towards nutrition and metabolism processes abnormality and that can play a role in genesis of pathological conditions. Recent researches arouse clinicians interest in determination of biofluid enzyme activity in different physiological and abnormal cases. Intestinal infections are followed by dysbacteriosis and obvious alterations in the hydrolase levels in the blood, urine and motions because of the changes of functional status of the liver, renal and intestinal barriers in relation to increted digestive enzymes. This causes an unfavorable course of recovery with the development of postinfectious digestion disorders as a result of previous acute diarrhea. Future researches are necessary to elaborate appropriate remodeling of developed pathosis with the help of enzymotherapy and probiotic diet.

Malabsorption syndrome with and without small intestinal bacterial overgrowth: a study on upper-gut aspirate using 1H NMR spectroscopy

Biochemicals in the upper-gut aspirate in 31 patients with malabsorption syndrome (MAS) with and without small intestinal bacterial overgrowth (SIBO), and 10 disease-free controls were analyzed using high-resolution (1)H-NMR spectroscopy, and were correlated with the degree of SIBO and severity of MAS. Compared to controls, the patients had higher quantities (micromol/L: median [range]) of total bile acids/cholesterol (2000 [0-12000] vs. 300 [0-600]), lactate (700 [0-5200] vs. nil [0-30]), acetate (200 [0-6500] vs. 20 [0-200]), and formate (80 [0-900] vs. nil [0-50]) (P < 0.01, Mann-Whitney U-test). However, amino acids and glucose were comparable in both. Quantities (micromol/L: median [range]) of acetate (1330 [220-6500] vs. 100 [0-1430]), lactate (1430 [670-3300] vs. 300 [0-5200]), formate (360 [0-600] vs. 25 [0-800]), and unconjugated bile acids (500 [40-600] vs. 10 [0-300]) were higher in MAS patients with SIBO than those without SIBO (P < 0.01, Mann-Whitney U-test, for all). In patients with MAS the quantity of acetate positively correlated with the degree of SIBO, and unconjugated bile acids correlated with the degree of steatorrhoea (Spearman's rank correlation coefficient, two-tailed, P < 0.05: 0.46 and 0.52, respectively). This study demonstrates the bacterial production of metabolites and deconjugation of bile acids in patients with MAS.

Small bowel bacterial overgrowth. An underrecognized cause of malnutrition in older adults

Small bowel bacterial overgrowth (SBBO) is an important and under-recognized clinical syndrome in the elderly. It is the most common cause of malabsorption among older adults. Presentation of SBBO syndrome is often occult, which makes it imperative to maintain a high index of suspicion for this disorder. When symptomatic bacterial overgrowth is appropriately identified and treated there can be positive dramatic results. This article discusses the importance of considering a diagnosis of bacterial overgrowth in those predisposed to its development and the mechanisms by which nutrient malabsorption occurs. Signs and symptoms of bacterial overgrowth, differential diagnosis, investigation, and current treatment options are discussed.

Utility of hydrogen breath tests in diagnosis of small intestinal bacterial overgrowth in malabsorption syndrome and its relationship with oro-cecal transit time

BACKGROUND

Small intestinal bacterial overgrowth (SIBO), which may result from intestinal stasis, is common in malabsorption syndrome (MAS). Quantitative culture of upper gut aspirate is used as a gold standard for the diagnosis of SIBO. Studies on diagnosis of SIBO using non-invasive hydrogen breath tests are contradictory.

METHODS

83 patients (age 35 [14-70] y; 50 men) with MAS due to various causes were investigated for SIBO using quantitative culture of upper gut aspirate obtained using a special endoscopic catheter and glucose and lactulose hydrogen breath tests (GHBT, LHBT). Sustained elevation in breath hydrogen of 12 ppm above basal and two separate peaks (one due to SIBO and the other from colon) were diagnostic of SIBO in GHBT and LHBT, respectively. Oro-cecal transit time (OCTT) was estimated using LHBT in 71 patients.

RESULTS

Thirty two of 81 (39.5%) patients with MAS had SIBO on culture (>or= 10(5) CFU/mL). Using aspirate culture as the gold standard, sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of GHBT to diagnose SIBO were 44%, 80%, 62%, 67% and 65%, respectively; the corresponding values for LHBT were 31%, 86%, 62%, 54% and 55%, respectively. OCTT in patients with SIBO diagnosed on GHBT and/or aspirate culture (n=58) was longer than in those without (170 [60-250] vs. 120 [50-290] min, p=0.02); of others, 7 were hydrogen non-producers and in 6 OCTT could not be assessed due to sustained early peak because of SIBO.

CONCLUSIONS

GHBT and LHBT are highly specific but insensitive for diagnosis of SIBO in MAS; OCTT is longer in patients with MAS and SIBO than in those without.

Sobrecrecimiento bacteriano intestinal: An update

Small intestinal bacterial overgrowth (SIBO) is characterized by nutrient malabsorption, associated with an excessive number of bacteria in the proximal small intestine. Unfortunately, the diagnosis of bacterial overgrowth presents several difficulties and limitations, and as yet there is not a widespread agreement on the best diagnostic test. SIBO occurs when there are alterations in intestinal anatomy, gastrointestinal motility, or a lack of gastric acid secretion. The true association between SIBO and irritable bowel syndrome and celiac disease remains uncertain. The treatment usually consists in the eradication of bacterial overgrowth with repeated courses of antimicrobials, nutritional support and when it is possible, the correction of underlying predisposing conditions.

Small bowel bacterial overgrowth: presentation, diagnosis, and treatment

Small bowel bacterial overgrowth (SBBO) syndrome is associated with excessive numbers of bacteria in the proximal small intestine. The pathology of this condition involves competition between the bacteria and the human host for ingested nutrients. This competition leads to intraluminal bacterial catabolism of nutrients, often with production of toxic metabolites and injury to the enterocyte. A complex array of clinical symptoms ensues, resulting in chronic diarrhea, steatorrhea, macrocytic anemia, weight loss, and less commonly, protein-losing enteropathy. Therapy is targeted at correction of underlying small bowel abnormalities that predispose to SBBO and appropriate antibiotic therapy. The symptoms and signs of SBBO can be reversed with this approach.

Search for Lawsonia intracellularis and Bilophila wadsworthia in malabsorption-diseased chickens

Proliferative enteropathy is an important enteric disease caused by Lawsonia intracellularis. A wide range of host species can be infected by the same bacterium, yet the clinico-pathologic features among these hosts remains almost identical. The disease has been recognized regularly among ratites, but not in other avian families, such as galliforms, even though these suffer uncharacterized enteric conditions. Fresh ileum-colon contents were obtained from 228, 3- to 8-week-old chickens with enteric disease, kept at 14 large commercial farms in the southern USA. DNA was extracted from each sample and subjected to polymerase chain reactions (PCR) with primers specific to eubacterial DNA, L. intracellularis, and Bilophila wadsworthia. All chicken samples were positive for eubacterial DNA, 29 chickens (13%) were positive for B. wadsworthia DNA, and none were positive for L. intracellularis DNA. Given the ubiquitous nature of L. intracellularis, we consider it likely that some avian families do not carry the necessary mechanism for L. intracellularis viability. Bilophila wadsworthia appears to be a consistent member of the colonic flora of some host animals. Neither bacterium appears to be associated with malabsorption syndromes in chickens.

Spectrum and antibiotic sensitivity of bacteria contaminating the upper gut in patients with malabsorption syndrome from the tropics

BACKGROUND

Various causes of malabsorption syndrome (MAS) are associated with intestinal stasis that may cause small intestinal bacterial overgrowth (SIBO). Frequency, nature and antibiotic sensitivity of SIBO in patients with MAS are not well understood.

METHODS

Jejunal aspirates of 50 consecutive patients with MAS were cultured for bacteria and colony counts and antibiotic sensitivity were performed. Twelve patients with irritable bowel syndrome were studied as controls.

RESULTS

Culture revealed growth of bacteria in 34/50 (68%) patients with MAS and 3/12 controls (p < 0.05). Colony counts ranged from 3 x 10(2) to 10(15) (median 10(5)) in MAS and 100 to 1000 (median 700) CFU/ml in controls (p 0.003). 21/50 (42%) patients had counts GreaterEqual;105 CFU/ml in MAS and none of controls (p < 0.05). Aerobes were isolated in 34/34 and anaerobe in 1/34. Commonest Gram positive and negative bacteria were Streptococcus species and Escherichia coli respectively. The isolated bacteria were more often sensitive to quinolones than to tetracycline (ciprofloxacin: 39/47 and norfloxacin: 34/47 vs. tetracycline 19/47, <0.01), ampicillin, erythromycin and co-trimoxazole (21/44, 14/22 and 24/47 respectively vs. tetracycline, p = ns).

CONCLUSIONS

SIBO is common in patients with MAS due to various causes and quinolones may be the preferred treatment. This needs to be proved further by a randomized controlled trial.

Enteric bacterial flora and bacterial overgrowth syndrome

Under certain conditions, colonic bacterial flora can colonize the upper small bowel in concentrations sufficient to cause mucosal damage and malabsorption of nutrients, vitamin B12, and fat-soluble vitamins. This situation, known as small bowel bacterial overgrowth syndrome (SBBOS) may be an under-appreciated cause of malnutrition in elderly people. The diagnosis of SBBOS should be considered when patients with known or suspected predisposing conditions have symptoms or findings compatible with this syndrome. However, proof of small bowel bacterial overgrowth requires specialized testing that is not readily available. Moreover, disagreement persists as to how best to test definitively for this disease. Therefore, on a practical level and despite the potential drawbacks of such a decision, SBBOS is usually diagnosed when a compatible syndrome responds to an empirical trial of appropriate oral antibiotics. Improvements on this approach to SBBOS will be built on more widespread access to sensitive, specific, and less cumbersome testing than is currently available.

Experimental reproduction of malabsorption syndrome with different combinations of reovirus, Escherichia coli, and treated homogenates obtained from broilers

Attempts to reproduce malabsorption syndrome (MAS) by oral inoculation with several different combinations including intestinal homogenate, reovirus, and hemolytic Escherichia coli obtained from MAS-affected chickens and intestinal homogenate from healthy chickens (healthy homogenate) were performed in 1-day-old specific-pathogen-free (SPF) broilers. The MAS homogenate, serving as a positive control, induced weight gain depression and intestinal lesions such as cystic crypts of Lieberkuhn, villus atrophy, and lymphoid and/or granulocytic infiltration. The healthy homogenate, the formalin-treated MAS homogenate, the formalin-treated healthy homogenate, and phosphate-buffered saline caused neither weight gain depression nor intestinal lesions. We were able to reproduce both weight gain depression and intestinal lesions by inoculation of reovirus either combined with the formalin-treated MAS homogenate or combined with healthy homogenate. Surprisingly, when hemolytic E. coli was added to the combination of reovirus with formalin-treated MAS homogenate, this did not cause weight gain depression although this combination caused the described intestinal lesions. Identical results were obtained with the combination of formalin-treated MAS homogenate with hemolytic E coli or the combination of reovirus with hemolytic E. coli. The intestinal lesions were more severe and developed faster by combinations including reovirus and formalin-treated MAS homogenate. This study indicates that a combination of enteropathogenic reovirus with other agents or substances that are present in an intestinal homogenate from MAS-affected and healthy chickens can induce MAS in SPF broilers. Escherichia coli is not essential for induction of weight gain depression but can play a role in development of intestinal lesions. Furthermore, intestinal lesions alone will not always result in weight gain depression.

[Cryptosporidium parvum: functional study of the intestinal malabsorption syndrome]

Cryptosporidiosis is an important cause of diarrhea associated with growth retardation in children and severe malnutrition in immunocompromised patients. The pathophysiology is poorly understood. In the suckling rat model, we show that C. parvum infection impairs net electrogenic transport across the ileal mucosa without involvement of prostaglandins, as well as trans- and paracellular permeability and leucine and glutamate absorption. These results provide evidence for the development of an intestinal malabsorptive syndrome during cryptosporidiosis. Unspecific process such as villous atrophy and inflammatory cytokines secretion should be regarded as possible mediators of this syndrome. However, specific mechanisms have to be considered since C. parvum induces a rearrangement of the host enterocyte cytoskeleton which might impaired intracellular trafficking thus reducing the membrane expression of nutrient transporters. Infection and malnutrition are known to be tightly associated, making each other worse. As no specific efficient therapy exists, cryptosporidiosis-induced malnutrition must be taken into account when establishing therapeutic scheme.

Reduced L-dopa absorption and increased clinical fluctuations in Helicobacter pylori-infected Parkinson's disease patients

We report that the area under the curve of L-dopa plasma concentration, following the administration of a single 250 mg L-dopa dose, is augmented after Helicobacter pylori (HP) eradication in six Parkinson's disease (PD) patients showing high IgG antibody titer against HP. A prolongation of L-dopa clinical benefit was also observed. We suggest that HP infection-activated gastric alterations may be responsible, at least in part, for the reported erratic efficacy of oral L-dopa therapy in some advanced PD patients. Given the high percentage of HP-positivity in the age cohorts including the largest prevalence of PD patients, we propose that HP eradication be recommended in all PD patients under L-dopa therapy.

Evaluation of the rice breath hydrogen test for small intestinal bacterial overgrowth

OBJECTIVES

The aims of this study were 1) to document the sensitivity, specificity, and predictive values of the rice breath hydrogen test for small intestinal bacterial overgrowth; 2) to determine the possible influence of concurrent gastric bacterial overgrowth and gastroduodenal pH on the efficacy of this test; and 3) to investigate whether reliability is limited by an inability of small intestinal luminal flora to ferment rice or its product of hydrolysis, maltose.

METHODS

Twenty adult subjects were investigated with microbiological culture of proximal small intestinal aspirate and a 3-g/kg rice breath hydrogen test. Gastroduodenal pH, the presence or absence of gastric bacterial overgrowth, and the in vitro capability of small intestinal luminal flora to ferment rice and maltose, its product of hydrolysis, were determined.

RESULTS

Sensitivity of the rice breath hydrogen test for small intestinal bacterial overgrowth was 33% and remained low even when subjects with small intestinal overgrowth with oropharyngeal-type (38%) and colonic-type flora (20%) and those with concurrent small intestinal and gastric bacterial overgrowth (40%) were considered separately. Sensitivity remained suboptimal despite favorable gastroduodenal luminal pH and documented ability of bacterial isolates to ferment rice and maltose in vitro. Specificity of the rice breath hydrogen test for small intestinal bacterial overgrowth was 91%. Positive predictive value, negative predictive value, and predictive accuracy were 75%, 63%, and 65%, respectively.

CONCLUSIONS

Clinical value of the rice breath hydrogen test for detecting small intestinal bacterial overgrowth is limited. The rice breath hydrogen test is not a suitable alternative to small intestinal intubation and culture of secretions for the detection of small intestinal bacterial overgrowth.

A comparative study of the pathogenesis of malabsorption syndrome in broilers

Five malabsorption syndrome (MAS) homogenates from The Netherlands and Germany were used to reproduce MAS in broilers. We studied the histopathology after inoculation of 1-day-old broiler chicks and the agents that might be involved. Generally, the MAS homogenates induced signs that differed in severity and pathobiology. We could distinguish and classify the inoculated groups best by histopathology: proventriculitis, lesions in the small intestines in combination with proventriculitis, or lesions of the small intestines only. Lesions in the small intestine had more impact on weight gain depression than lesions in the proventriculus. In three out of five inoculated groups, microscopic lesions of the pancreas were found. Reovirus was detected in the inoculated groups by virus isolation and seroconversion, and reoviral antigen was detected by immunohistochemistry of the small intestine. Also, enteroviruslike particles were detected in three of the five inoculated groups, although not in the most affected group. Additionally, bacteriophages and bacteria (hemolytic Escherichia coli, Pasteurella hemolytica, and Enterococcus durans) were isolated from inoculated chicks. The role these agents play in pathogenesis of MAS is still unsolved.

Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome

OBJECTIVE

Small intestinal bacterial overgrowth syndrome (SIBOS) is characterized by an abnormally high bacterial population level in the upper gut, exceeding 10(5) organisms/ml (5 log colony-forming unit (CFU)/ml). To understand its origin and select an appropriate antibiotic treatment, we have analyzed the bacterial populations contaminating the upper gut in SIBOS patients.

METHODS

Jejunal samples of 63 consecutive patients with diarrhea or malabsorption and conditions predisposing to SIBOS were cultured and antibiotic sensitivities determined.

RESULTS

Concentrations of total, microaerophilic, and anaerobic bacteria were confirmed in 55 patients with SIBOS (mean +/- SE) 7.6 +/- 0.8, 7.4 +/- 0.9, and 6.1 +/- 0.7 log CFU/ml, respectively. Mean number of bacterial genera was 4.6 +/- 0.8. The main bacteria recovered were (mean +/- SE log CFU/ml) Streptococcus (71%; 6.4 +/- 0.8), Escherichia coli (69%; 7.2 +/- 0.9), Staphylococcus (25%; 6.2 +/- 0.6), Micrococcus (22%; 6.0 +/- 0.7), Klebsiella (20%; 7.1 +/- 0.8), Proteus (11%; 6.1 +/- 0.8) for microaerophilic bacteria, and Lactobacillus (75%; 6.1 +/- 1.1), Bacteroides (29%; 6.9 +/- 1.3), Clostridium (25%; 5.5 +/- 1.0), Veillonella (25%; 5.3 +/- 0.7), Fusobacterium (13%; 4.8 +/- 0.5), and Peptostreptococcus (13%; 6.1 +/- 0.7) for anaerobic bacteria. Amoxicillin-clavulanic acid and cefoxitin were efficient on >90% of strains.

CONCLUSIONS

Contaminating flora isolated in SIBOS include commonly identified oropharyngeal and colonic flora, but these occur in SIBOS at different levels from those usually found in their original location. These data may hopefully serve as a starting point to further therapeutic controlled studies.

Ascorbic acid absorption in patients with systemic sclerosis

OBJECTIVE

To investigate whether reduced circulating levels of ascorbic acid in patients with systemic sclerosis (SSc) are a result of malabsorption.

METHODS

Eight patients with SSc, but with no evidence of bacterial overgrowth, and 8 healthy controls were recruited. On the first day of study, each subject was given orally an aliquot of [14C] ascorbic acid, which was then "flushed out" by oral intake of unlabeled ascorbic acid for the following 7 days. Plasma samples were collected at specified intervals and urine was collected continuously over the 8 day study period. [14C] content of plasma and urine were measured by scintillation counting. For each subject, a plasma [14C] decay curve was drawn. Each subject's ascorbic acid absorption was assessed using the area under the curve (AUC) and the apparent renal clearance (CLr[app]). Ascorbic acid intake was assessed using dietary history and food composition tables.

RESULTS

There were no differences in the dietary intake of vitamin C (p = 0.16) and body mass indices (p = 0.91) between patients and controls. The plasma [14C] AUC and CLr(app) were similar between patients and controls [AUC patient mean (standard deviation, SD) = 37.1 (6.8), AUC control mean (SD) = 38.6 (9.9), p = 0.74; CLr(app) patient mean (SD) = 0.57 (0.24), CLr(app) control mean (SD) = 0.47 (0.27), p = 0.45].

CONCLUSION

There was no evidence of impaired absorption of ascorbic acid in patients with SSc without bacterial overgrowth compared to healthy controls.

Nutritional impact and ultrastructural intestinal alterations in severe infections due to enteropathogenic Escherichia coli strains in infants

OBJECTIVE

Enteropathogenic Escherichia coli (EPEC) strains are able to adhere to human intestinal tissue inducing a typical lesion causing dissolution of the brush border membrane and loss of microvillus structure at sites of bacterial attachment. The presence of these lesions can provoke perpetuation of diarrhea associated with malabsorption of the nutrients and nutritional aggravation. In this paper we report the nutritional impact of severe EPEC gastroenteritis in infants in a small bowel ultrastructural study.

METHODS AND RESULTS

Two infants aged 3 months and one 4 month old infant with profuse watery diarrhea lasting less than 6 days were studied. After rehydration therapy, the patients were fed a cow's milk formula and since food intolerance was diagnosed, a protein-hydrolisate, lactose-free formula was introduced. This dietary modification was successful, diarrhea ceased, the patients were discharged and followed up for 30 days. The following EPEC strains were identified in the stools and in the jejunal secretion: O111ab:H2, O119:H6 and O18ab:H14. A small bowel biopsy was performed and the electron microscopic study revealed bacteria tightly adhered to the apical portion of the enterocyte and effacement of the microvilli. These lesions were more prominent in the areas where bacteria were present.

CONCLUSION

The patients underwent an acute nutritional aggravation due to food intolerance, but the introduction of a protein-hydrolisate, lactose-free formula, allowed prompt cessation of diarrhea and nutritional recovery.

Persisting diarrhoea and malabsorption

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Helicobacter pylori infection and food-cobalamin malabsorption

Two entities of considerable recent interest, Helicobacter pylori infection of the stomach and food-cobalamin malabsorption, are each intimately associated with gastric abnormalities. A possible connection between the two entities thus suggested itself and prompted us to study 98 subjects with low serum cobalamin levels but normal Schilling test results and 17 controls with normal cobalamin levels. Food-cobalamin absorption was measured with the egg yolk-cobalamin absorption test (EYCAT) and was abnormal in 56 of the 115 subjects. IgG antibody to H. pylori was found in 78% of the 27 patients with severe food-cobalamin malabsorption (EYCAT < 1.0% excretion), compared with only 45% of 29 subjects with mild malabsorption (EYCAT 1.0-1.99%) and 42% of 59 subjects with normal absorption (EYCAT > or = 2.0%) (chi 2 = 9.52, P < 0.01). Antibody-positive patients had lower EYCAT excretion values than those without antibody (2.03 +/- 1.83% vs 3.11 +/- 2.13%, t = 2.913, P = 0.005). While Hispanic patients tended to malabsorb food cobalamin more frequently than did white or black patients, and men were more often antibody-positive than women, race, sex, or age characteristics were not responsible for the significant association between serologic evidence of H. pylori infection and severe malabsorption of food cobalamin. The association that we describe suggests that gastritis induced by H. pylori predisposes to a more severe form of food-cobalamin malabsorption, among its other effects on gastric status.

A syndrome of cirrhosis, achlorhydria, small intestinal bacterial overgrowth, and fat malabsorption

OBJECTIVES

The purposes of this report were to examine whether or not a positive bile acid breath test in cirrhotic patient was associated with bacterial overgrowth in the upper small intestine, to verify that these bacteria have deconjugation ability, and, in addition, to elucidate whether or not changes in the gastric pH are related to bacterial overgrowth.

METHODS

Twenty-seven patients with liver cirrhosis were tested by breath analysis technique using glycine-1-14C-labeled glycocholate. Jejunal fluids were aspirated through a double-lumen tube with a rubber cover on the tip. Anaerobes and aerobes were isolated and identified. After culturing, we used thin layer chromatography to determine whether each bacteria had the ability to deconjugate bile salts.

RESULTS

Expired breath samples from seven of 27 patients with liver cirrhosis showed a marked increase of 14CO2-specific activity. Bacterial overgrowth was found in the jejunal fluid of these patients. Administration of chloramphenicol to the seven patients reduced 14CO2 specific activity significantly. The majority of the species identified deconjugated bile acids. Seventeen healthy control subjects showed no increase in CO2 excretion, and 16 of the 17 had no bacteria isolated from jejunal fluid. The relationship between 14CO2 specific activity of expired breath samples and gastric pH was also tested in the cirrhotic patients. There was a relatively good correlation (n = 27, r = 0.87, p < 0.05) between 14CO2 activity and gastric pH.

CONCLUSION

We conclude that some patients with liver cirrhosis have bacterial overgrowth in the proximal small intestine that contains species that can deconjugate bile salts, and that the bacterial overgrowth is probably associated with the shift to alkaline pH in gastric juice.

Intestinal malabsorption presenting with night blindness

Night blindness from vitamin A deficiency was observed in a patient with intestinal malabsorption, which in turn was attributable to duodenal diverticulosis and bacterial growth. Monthly supplementation with vitamin A and correction of bacterial overgrowth with tetracycline resulted in a normalisation of plasma retinol levels and resolution of the night blindness.

Breath hydrogen excretion in patients with alcoholic liver disease--evidence of small intestinal bacterial overgrowth

The hydrogen breath test has been used to investigate the incidence of small-bowel bacterial overgrowth in 45 chronic alcoholics and in 60 controls with no history of alcohol abuse. In the group of patients with alcoholic liver disease, the percentage of cases with bacterial overgrowth was almost three times (37.8%) that of controls not abusing alcohol (13.3%; p < 0.001). A separate evaluation of alcoholics with cirrhosis in comparison with those without cirrhosis, revealed no significant difference in the incidence of bacterial overgrowth (42.9% and 33.3%; p > 0.05). Some 16.7% of the controls and 8.9% of the patients with alcoholic liver disease were classified as "non-excreters". Among patients with alcoholic liver disease, the mouth-to-caecum transit time was prolonged by 21.5% in comparison with the controls not abusing alcohol (p < 0.025). The results suggest that bacterial overgrowth might contribute to the functional and/or morphological abnormalities of the small intestine commonly found in patients with chronic alcohol abuse.

The clinical importance of hypochlorhydria (a consequence of chronic Helicobacter infection): its possible etiological role in mineral and amino acid malabsorption, depression, and other syndromes

In a previous paper evidence was presented to show that Helicobacter-induced chronic gastritis is the probable cause of most chronic hypochlorhydria. In this article evidence is presented for the clinical relevance of reduced stomach acid secretion. Reduced mineral absorption is fairly well documented and has sound theoretical support from basic chemistry. Impaired digestion of protein has been suggested by a few studies. Small intestinal bacterial overgrowth in hypochlorhydria probably leads to putrefactive breakdown of the metobolically useful products of protein digestion, thereby reducing their availability for certain essential pathways. The possible lowering of tryptophan, tyrosine, and phenylalanine in the blood may be a precipitating factor in depression in hypochlorhydric patients. In reduced or absent stomach acid secretion a constellation of gastrointestinal symptoms has been consistently observed and reported by clinicians in the past, and treatment of the hypochlorhydria with hydrochloric acid or its substitutes has often been observed to be effective in reducing these symptoms.

Non-absorbable antibiotics and small bowel bacterial overgrowth

The normal gastrointestinal flora includes no more than 10(3) organisms/ml of gastric aspirate and no more than 10(5) organisms/ml of duodenal or jejunal juice. The organisms are primarily gram-positive and aerobic bacteria. In particular anatomical or functional predisposing conditions, an abnormal colonization takes place in the small bowel with microbial concentrations > or = 10(7)/ml of aspirate and with a predominance of anaerobes and coliforms. At times this small bowel bacterial overgrowth remains asymptomatic, but more often leads to a true malabsorption syndrome with symptoms, such as diarrhoea, weight loss and megaloblastic anemia. The most accurate procedure for confirming the presence of this condition is represented by the bacterological analysis of the jejunal aspirate. The routine use of this method is, however, notably hindered by the need for intubation of the patient and by the lack of laboratories suitably equipped for anaerobe culture. As an alternative to this complex procedure, numerous non-invasive tests have been perfected over the last few years, including the glucose- or lactulose- H2 breath test. The main aim of the treatment of the small bowel bacterial overgrowth is the suppression of the bacterial colonization using antimicrobial therapy. Among the local-action non-absorbable antibiotics, rifaximin, was shown to have bactericidal activity against aerobes and anaerobes bacteria, such as bacteroides, lactobacilli and clostrides. In controlled clinical trials the antibiotic has demonstrated therapeutic efficacy in bacterial origin diarrhoea, in porto-systemic encephalopathy, in diverticulosis and, finally, in small bowel bacterial overgrowth.

Evidence that bacteria are not causative agents of stunting syndrome in poults

Two experiments were conducted to determine the effect of removing bacteria, including long segmented filamentous organisms (LSFO), from inoculum known to induce stunting syndrome (SS) in poults. Experiment 1 consisted of two identically designed trials. In each trial, each of four treatments was assigned to an isolator. Three treatments consisted of dosing, by crop intubation, groups of 1-day-old poults with unfiltered SS inoculum or filtrate of inoculum passed through .45- or .20-micron microfilters. Uninoculated poults were dosed with inoculum carrier, saline. Experiment 2 was done in battery facilities. Three rooms were used and each room housed one of three treatment groups. Triplicate pens of 10 poults each within each room were dosed by crop intubation with saline (uninoculated), unfiltered inoculum, or filtrate from .20-micron filtration. As compared with uninoculated poults, weight gain through 7 days was reduced 20% (P less than .05) by unfiltered and filtered inocula in both experiments. Jejunal maltase activity also was decreased (P less than .01) by unfiltered and filtered inocula. Feed efficiency (FE) was not determined in Experiment 1, but in Experiment 2, FE from 1 to 14 days of age was impaired by inoculum, irrespective of filtration. This effect was not evident during the 14- to 20-day period. The observation that the adverse effects of giving filtered inoculum to poults were the same as those caused by unfiltered inoculum indicated that bacteria, including LSFO, were not primary causative agents of the SS experimentally induced in poults.

Epidemiology of small bowel bacterial overgrowth and rice carbohydrate malabsorption in Burmese (Myanmar) village children

Breath hydrogen tests were performed after a rice meal (3 g of cooked rice/kg of body weight, equivalent to 1 g of carbohydrate/kg of body weight) on 256 village children (age range 1-59 months) who were known hydrogen (H2) producers. Anthropometric measurements were made every three months and growth rates were calculated. A breath H2 excretion pattern that suggested small bowel bacterial overgrowth (SBBO), which was recognized as a transient maximum level of 10 ppm or more at 20-, 40-, or 60-min breath samples following the rice meal, was present in 53 (20.7%) children, and was more frequent in children 36-47 and 48-59 months old. This breath H2 excretion pattern was detected in 48 (33.3%) of 144 children who were rice malabsorbers (greater than 10 ppm H2 above baseline values in one of the breath samples taken between 90 and 240 min), and in only five (4.5%) of 112 rice absorbers. Children who had SBBO had a high relative risk (10.7) of being rice malabsorbers. Rice malabsorbers have a high relative risk (59.7) of having faltered growth, accompanied by a large etiologic fraction (94%). This same risk (6.68) and an etiologic fraction of 62% exist in children with untreated SBBO. These findings emphasize the need for interventions aimed at reducing the prevalence of SBBO or similar conditions as detected by the breath H2 excretion pattern to prevent rice malabsorption and growth faltering.

Small-bowel bacterial overgrowth in elderly people: clinical significance and response to treatment

Duodenal-jejunal bacterial overgrowth is increasingly recognized in old age but its clinical significance is poorly defined. In this study, 16 elderly subjects were selected on the basis of an abnormal lactulose breath hydrogen test from a series of 27 in whom there was some reason to suspect malabsorption. In 12 of these 16 cases, pentagastrin tests showed normal gastric acid secretion and in 12 cases the small bowel was radiologically normal. Nutritional assessment, anthropometric measurements, culture of small-bowel aspirates, 14C-triolein breath tests and blood xylose tests were performed before and after 4 to 6 months of cyclical antibiotic therapy. Initially all patients except two showed evidence of malabsorption. After antibiotic treatment alone, 13 patients gained in weight and body fat. There were significant rises in the mean levels of haemoglobin, serum protein and calcium. Blood xylose test levels increased in 14 cases, reaching normal in all except one, whereas 14C-triolein excretion also increased in 14 and reached normal in 12 out of 16 cases. The breath hydrogen test reverted to normal in all cases and bacterial overgrowth was eliminated in 10 out of 11. The mouth-to-caecum transit time was prolonged initially (mean 190 min) and was unaffected by therapy (mean 196 min). Malabsorption and undernutrition are significant features of small-bowel overgrowth in the elderly and can be specifically corrected by antibiotic treatment. The clinical effect can be equally severe in elderly patients with or without an anatomical defect of the small bowel.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics and analysis of electropherotypes of avian reovirus field isolates

Genomic segments of 10 selected isolates of avian reoviruses recovered from the intestine of birds affected with malabsorption syndrome or runting/stunting syndrome were separated by polyacrylamide gel electrophoresis. Different electropherotypes were observed and analysed, depending on the period of recovery and particular geographic locations. The analysis showed great variability in the dsRNA profiles of the isolates and higher mobility of the segments L1, S1, S2, S3 and S4. There was no correlation between electropherotype and geographic origin of the isolate. The analysis also showed the emergence of electropherotypically distinct strains since the introduction of modified live reovirus vaccines.

[Immunohistochemical studies in contaminated small bowel syndrome]

This study was undertaken to evaluate the number of the immunoglobulin producing cells in the lamina propria of the small intestine by immunocytochemical techniques, using peroxidase-antiperoxidase (PAP) complex in normacid patients with CSBS. 25 patients were studied including 13 patients with bacterial overgrowth, where the bacterial concentration was higher than 10(4) colony forming units/ml, and 12 subjects with normal bacterial concentration, served as control. The patients with CSBS were treated with antibiotics according to the antibiotic resistance. After treatment the luminal bacterial concentrations was lower than 10(4) cfu/ml in 7 of 13 patients (CSBS I. group). In 6 patients the bacterial concentration remained high (CSBS II. group). The immunoglobulin producing cells were determined in biopsy specimens taken from the lower part of duodenum. The number of the IgA and IgM producing immunocytes was significantly decreased only in the CSBS II. group. Our results show that temporary immunological alterations may play an important role in the mechanism of the recurrent CSBS.

Experimental infection in specific-pathogen-free chicks with avian reovirus and avian nephritis virus isolated from broiler chicks showing runting syndrome

Avian reovirus (ARV) and avian nephritis virus (ANV) were individually isolated from runty 10-day-old broiler chicks. The ARV isolate, IR-R, the ANV isolate, IR-N, and the reference strain of ANV, G-4260, were inoculated orally into 1-day-old chicks of two specific-pathogen-free (SPF) chicken lines, 151 and PDL-1. Growth retardation without the presence of gross lesions was clearly observed at 7 and 14 days postinoculation (PI) in chicks of both lines inoculated with the IR-R strain. On the other hand, in chicks inoculated with IR-N strain, growth retardation was observed only in the chicks of line 151 at 7 and 14 days PI. Microscopically, nephritis was observed in both chicken lines at 7 and 14 days PI. When chicks that were inoculated with the IR-N strain at 1 day of age were inoculated with the IR-R strain at 3 days of age, growth retardation was observed in the chicks of line PDL-1 at 10 and 17 days PI. However, the growth retardation was less severe than in the group receiving a single inoculation of the IR-R strain.

Intestinal malabsorption syndromes

This chapter is a review of selected causes of intestinal malabsorption. The pathogenesis and clinical features of malabsorption due to acquired immunodeficiency syndrome (AIDS), celiac sprue, and small bowel bacterial overgrowth are discussed, with emphasis on recent developments. The etiology and diagnostic challenges of malabsorptive disorders in the elderly are also reviewed.

Comparative study of the pathogenicity of avian reoviruses

Reovirus strains CO8 and 81-5, isolated from chickens with malabsorption syndrome, and reovirus strain 176, isolated from chickens with tenosynovitis, were each individually inoculated into 1-day-old specific-pathogen-free chicks. Strain CO8 caused tenosynovitis and pericarditis following footpad inoculation, but it was of low pathogenicity when given by either oral or subcutaneous route. In contrast, strains 81-5 and 176 were highly pathogenic and caused severe mortality following subcutaneous inoculation. Lesions included hepatic necrosis, bursal atrophy, thymitis, and splenic hyperplasia; strain 81-5 also caused pericarditis and myocarditis. Although strain 176 caused higher mortality than strain 81-5, these two strains differed little in the severity and distribution of the lesions they caused. No signs or lesions of typical malabsorption syndrome were observed.