Hydrogen (H2) breath test and gastric bacteria in acid-secreting subjects and in achlorhydric and postgastrectomy patients before and after antimicrobial treatment

Association between symptoms of irritable bowel syndrome and methane and hydrogen on lactulose breath test

Whether hydrogen and methane gas produced during lactulose breath test (LBT) are associated with symptoms of irritable bowel syndrome (IBS) is not determined. We aimed to investigate whether hydrogen and methane on LBT are associated with IBS symptoms. Sixty-eight IBS patients meeting the Rome III criteria for IBS, and 55 healthy controls, underwent LBT. The IBS subjects recorded their customary gastrointestinal symptoms on a questionnaire using visual analogue scales. LBT positivity was defined to be above 20 ppm rise of hydrogen or 10 ppm rise of methane within 90 min. Gas amounts produced during LBT were determined by calculating area under the curve of hydrogen and methane excretion. Symptom severity scores were not different between the LBT (+) IBS and LBT (-) IBS subjects and also between methane producers and non-methane producers. Gas amounts produced during LBT were not associated with IBS symptoms, except a weak correlation between total gas amounts and a few IBS symptoms such as bloating (r = 0.324, P = 0.039), flatulence (r = 0.314, P = 0.046) and abdominal pain (r = 0.364, P = 0.018) only in LBT (+) IBS. In conclusion, hydrogen and methane gas on LBT are not useful for predicting the customary symptoms and subtypes of IBS.

Influence of colectomy on hydrogen excretion in breath

INTRODUCTION

Hydrogen breath test is the most commonly used method to analyze carbohydrate absorption and diagnose carbohydrate malabsorption. The result of the H(2) breath test is influenced by different factors, which are mostly related to quantitative or qualitative aspects of colonic flora. A scarcely studied variable is the effect of colonic anatomical integrity on H(2) excretion in breath.

PURPOSE

The present study aims to determine whether loss of colonic integrity reduces H(2) excretion capacity after an oral load of an unabsorbable carbohydrate.

METHODS

An observational study was conducted in three patient groups: controls with preserved colon, patients with partial colectomy, and patients with complete colectomy and ileostomy. H(2) concentration in breath was measured by gas chromatography every 10 min for 3 h after oral lactulose administration.

RESULTS

Twenty-two patients with partial colectomy, 18 controls with preserved colon, and seven patients with ileostomy were included. H(2) excretion after lactulose did not differ between patients with partial colectomy and controls (basal excretion = 8.5 vs 4 ppm; delta increase = 50.0 vs 47.5 ppm; area under the curve = 4,480.0 vs 4,710.5 ppm/min). In contrast, H(2) excretion was significantly lower in the ileostomy group.

CONCLUSIONS

Partial colectomy does not influence the capacity for H(2) excretion after oral unabsorbable carbohydrate administration.

Latest results (12-21 years) of a prospective randomized study comparing Billroth II and Roux-en-Y anastomosis after a partial gastrectomy plus vagotomy in patients with duodenal ulcers

INTRODUCTION

After a partial resection of the stomach, the continuity of the gastrointestinal tract can be restored either by a Billroth II gastrojejunal anastomosis or a Roux-en-Y gastrojejunostomy. Each procedure has its advantages and disadvantages.

OBJECTIVE

To determine through a prospective and random clinical trial, the clinical outcome and the endoscopic and histologic alterations of the distal esophagus and the gastric remnant in patients who received a partial distal gastrectomy due to duodenal ulcers and a Billroth II or Roux-en-Y reconstruction.

MATERIAL AND METHODS

In this prospective random trial, a total of 75 patients with duodenal ulcers were included. A bilateral selective vagotomy and partial distal gastrectomy were performed in all patients. A Billroth II or Roux-en-Y 60-cm-long loop was randomly used for reconstruction of the gastrointestinal tract. During the latest follow-up clinical evaluation, upper endoscopy and biopsy samples from the distal esophagus and gastric remnant were obtained.

RESULTS

There was 1 operative mortality and 6 patients had some morbidity. The average follow-up period was 15.5 years (range, 11-21). Patients with Roux-en-Y gastrojejunostomy were significantly more asymptomatic and had greater Visick I grading than patients with Billroth II reconstruction (P < 0.001). In the distal esophagus, endoscopic findings were normal in 90% of the Roux-en-Y group, but only in 51% of the Billroth II group (P < 0.0009). Nearly 25% of the latter group had the appearance of a short-segment Barrett esophagus compared with 3% of the Roux-en-Y group (P < 0.0001). The gastric remnant endoscopic findings were normal in 100% of the Roux-en-Y group and in 18% of the Billroth II group (P < 0.02). Histologic analyses showed similar proportions of normal fundic mucosa and chronic active fundic gastritis. However, chronic atrophic fundic gastritis and intestinal metaplasia were significantly more frequent after Billroth II reconstruction (P < 0.008). Helicobacter pylorus was present in a similar proportion of patients.

CONCLUSIONS

This prospective and random study showed that Roux-en-Y gastrojejunostomy is significantly better than a Billroth II reconstruction in patients with duodenal ulcers, through subjective and objective endoscopic and histologic evaluations during the latest follow-up evaluation.

Intestinal permeability and bacterial growth of the small bowel in patients with primary sclerosing cholangitis

OBJECTIVE

Animal studies show that small intestinal bacterial overgrowth and infusion of bacterial antigens into portal blood cause hepatic histological changes similar to those seen in primary sclerosing cholangitis in man. It has been suggested that aa similar mechanism involving bacterial overgrowth with increased small-bowel permeability may play a pathogenic role in patients with primary sclerosing cholangitis (13 M, 9 F, median age 37 years, range 21-74 years), 19 of whom (83%) had quiescent inflammatory bowel disease, were included in the study along with 18 healthy volunteers (9 F, ( M, median age 36 years, range 23-80 years). Small-bowel bacterial overgrowth was defined as the presence of colonic flora>10(5) colony-forming units (cfu)/ml from duodenal aspirations. Small-bowel intestinal permeability was assessed as the differential urinary excretion of lactulose/L-rhamnose.

RESULTS

Bacterial overgrowth was evident in one patient with primary sclerosing cholangitis (4.5%) (Enterobacter) and in none of the controls. Intestinal permeability in patients with primary sclerosing cholangitis (0.034 (0.026-0.041) (median, interquartile range (IQR)) did not differ significantly from that of the controls (0.033 (0.025-0.041).

CONCLUSIONS

Small intestinal bacterial overgrowth and increased intestinal permeability does not seem to play an important pathogenic role in patients with primary sclerosing cholangitis.

Changes in gastric mucosa and luminal environment during acid-suppressive therapy: a review in depth

Acid-suppressive therapy and subsequent changes in gastric mucosa and luminal environment rank highly amongst the investigated issues in gastroenterology over the past two to three decades. Herewith, we present an overview of these intragastric changes, particularly during long-term administration of acid-suppresive medication and concurrent infection with Helicobacter pylori. Current evidence indicates that: i) Long-term acid suppression facilitates the development of fundic ECL cell hyperplasia, especially in the presence of Helicobacter pylori. No neoplastic changes directly attributable to acid suppression have so far been demonstrated in humans. ii) Acid-suppressive therapy increases the risk of enteric infections. iii) Acid-suppressive therapy does not alter fat and mineral bioavailability, but may decrease the absorption of protein-bound vitamin B12. iv) Acid suppression invariably results in intragastric overgrowth of non-Helicobacter pylori bacterial species. The concurrent infection with Helicobacter pylori may promote this bacterial overgrowth and the intragastric formation of N-nitrosamines. v) Acid-suppressive therapy alters the natural course of Helicobacter pylori gastritis, transforming the antral-predominant pattern into a body-predominant pattern, which in turn may progress to body gland atrophy. The pathophysiology of this phenomenon is currently under investigation. vi) In view of the potential adverse effects of acid suppression in the presence of Helicobacter pylori, the screen-and-treat strategy is advocated for Helicobacter pylori in subjects considered for long-term treatment.

Comparison of the bacterial flora of the duodenum in healthy cats and cats with signs of gastrointestinal tract disease

OBJECTIVE

To determine whether a colony environment predisposes healthy cats to high bacterial counts, including counts of obligate anaerobes, in the duodenum and whether increased numbers of bacteria could be found in the duodenum of cats with signs of chronic gastrointestinal tract disease.

DESIGN

Prospective study.

ANIMALS

20 healthy control cats (10 from a colony environment and 10 pet cats) and 19 cats with a history of chronic gastrointestinal tract disease.

PROCEDURE

Undiluted duodenal fluid was quantitatively and qualitatively assessed by bacteriologic culture under aerobic and anaerobic conditions. Serum concentrations of cobalamin and folate were also measured.

RESULTS

Significant differences were not detected in the numbers of bacteria found in the duodenum of cats housed in a colony environment, compared with pet cats fed an identical diet prior to sampling. All healthy cats were, therefore, combined into 1 control group. Compared with healthy cats, cats with clinical signs of gastrointestinal tract disease had significantly lower counts of microaerophilic bacteria, whereas total, anaerobic, and aerobic bacterial counts were not significantly different. None of the cats with disease had total bacterial counts higher than expected from the range established in the control cats. Differences were not detected in regard to serum folate or cobalamin concentrations between diseased and healthy cats.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings indicated that healthy colony cats and pet cats have high numbers of bacteria in the duodenum, including high numbers of obligate anaerobes. Our findings also suggest that bacterial overgrowth in the small intestine is not a common clinical syndrome in cats with chronic nonobstructive gastrointestinal tract disease.

Evaluation of immunohistochemistry for the detection of Helicobacter pylori in gastric mucosal biopsies

A reliable diagnosis of Helicobacter pylori is important in clinical practice and research. To evaluate sensitivity, specificity and inter-observer variation of three histological staining methods for the diagnosis of intragastric H. pylori bacterial flora, four observers assessed the presence of H. pylori in a test set of pairs of gastric biopsies taken from 40 patients during GI-endoscopy. Histological slides of one biopsy of each patient (formalin-fixed and paraffin-embedded) were stained with a Modified Giemsa (MG), the Warthin-Starry (WS), and an immunohistochemical method (IMM) using purified polyclonal H. pylori antiserum (DAKO B471). As a standard, bacterial culture was performed on the adjacent biopsy, using the four quadrants method. Special attention was paid to the presence of non-H. pylori bacterial flora. Twenty out of 40 specimens were H. pylori-positive by culture. Using culture as a standard, sensitivity for H. pylori was 90.0+/-10.0% with MG, 70.0+/-14.1% with WS, and 83.8+/-11.1% with IMM stain. Specificity was 53.8+/-19.3%, 82.5+/-9.6% and 90.0+/-0.0%, respectively. Of 37, 14 and eight false positive scores by all observers for MG, WS and IMM, respectively, non-H. pylori flora was cultured from 17, six, and four of the corresponding adjacent biopsies. Non-H. pylori flora may account for overdiagnosis of H. pylori in gastric biopsies. Kappa values for the variance between the four observers were 0.28 for MG, 0.57 for WS, and 0.83 for IMM. Immunohistochemical staining for H. pylori is highly specific and has a low inter-observer variation. We advise that in situations where gastric histology is the main diagnostic tool, IMM should be used for the detection of H. pylori.

Effects of acid suppression on microbial flora of upper gut

Decreased acid secretion, due to therapy or disease, predisposes to increased bacterial counts in gastric juice. As bacterial numbers increase, the number of nitrate-reducing strains and the concentration of luminal nitrite usually also increase. However, there is controversy (mainly because of assay problems) about whether decreased acid increases generation of N-nitroso compounds: these may be produced by acid or by bacterial catalysis, and the relative contributions of each are still uncertain. Other potentially important factors include ascorbate secretion (can prevent nitrite conversion to nitroso compounds) and the particular spectrum of nitroso compounds produced. Nitrosation of several histamine H2-receptor antagonists has been demonstrated experimentally, but under conditions that are very unlikely to be encountered clinically. Some acid suppressant therapies have been claimed to aid eradication of Helicobacter pylori, but more work is needed to evaluate this. If ulcer treatment regimens do not also address eradication of H. pylori (when present), gastritis will progress, and the recently documented association between H. pylori and gastric carcinoma needs to be considered. Enteric flora probably also increase if acid secretion is markedly reduced: this does not appear to have nutritional consequences but probably reduces the resistance to occasional infections, of which cholera is the best documented.

Effect of gastrectomy with either Roux-en-Y or Billroth II anastomosis on small-intestinal function

This prospective study was undertaken in patients scheduled for gastrectomy for peptic ulcer disease to determine the effect of partial gastrectomy with either Roux-en-Y (n = 11) or Billroth II anastomosis (n = 11) on the function of the small intestine. Patients were studied before and at 6 months (blood and small-intestinal function tests) and at 24 months (blood tests) postoperatively. Median postoperative body weights at 6 months (70.5 kg; p less than 0.01) and 12 months (70.3 kg; NS) were lower than preoperatively (73.0 kg). Haemoglobin concentrations at 6 months (8.9 mM; p less than 0.01) and at 24 months (9.1 mM; p less than 0.05) were also significantly reduced compared with the preoperative value (9.5 mM). However, neither at 6 nor at 24 months postoperatively were there significant changes for serum iron, iron saturation, folic acid, vitamin B12, protein, albumin, alkaline phosphatase, and calcium concentrations. Whereas no significant deterioration of the absorption of D-xylose and vitamin B12 or of faecal fat excretion was observed, the orocoecal transit time was significantly shortened from 98 to 50 min (p less than 0.01), the expiratory hydrogen excretion after a 50-g oral glucose load was significantly increased from 8 to 54 ppm (p less than 0.01), as was indicanuria from 257 to 368 mumol/24 h (p less than 0.01). Apart from a lower serum iron concentration and iron saturation index in the Roux-en-Y patients 6 months postoperatively (p less than 0.05), no significant differences between the two types of anastomosis were observed. It is therefore concluded that both in patients with Roux-en-Y and in those with Billroth II anastomosis most abnormalities observed after gastrectomy are secondary to an accelerated small-intestinal transit.

Hydrogen (H2) breath excretion in peptic disease before and during treatment with ranitidine

Gastric juice pH, bacterial flora, and the H2 breath excretion were studied in patients treated with 150 mg ranitidine twice daily. The intragastric pH and bacterial contents rose during therapy. Before treatment upper respiratory tract bacteria were found in 4 of 23 patients and after 4 weeks of medication in 15 of 23. The median bacterial concentration was increased (p less than 0.01) and in five patients included bacteria normally found in the colon. Prolonged therapy for up to 12 weeks (n = 8) did not further change the bacteriologic pattern. Prophylactic treatment for 1 year (n = 3) showed gastric bacteria in high concentration, including Pseudomonas, in one patient. Postprandial H2 production remained unchanged after 4 (n = 23) and 12 (n = 7) weeks of therapy. In two of three patients treated prophylactically H2 excretion was increased after 1 year of medication. We conclude that acid reduction with ranitidine causes changes of the intragastric bacterial flora similar to those with other acid-reducing drugs in equipotent doses. The unchanged H2 breath test result after 4 and 12 weeks of treatment contradicts small-intestinal bacterial overgrowth. The elevated H2 excretion in two of the three patients after 1 year of treatment suggests the importance of a time factor in small-intestinal bacterial colonization.

The enzymology of intestinal disease

The role of enzyme estimations is reviewed. Serum levels of most enzymes do not alter significantly in intestinal diseases because dying mucosal cells slough off into the lumen. Similarly, biopsy material may provide misleading results because of lack of homogeneity between diseased and normal segments of bowel, whether in inflammatory or neoplastic conditions. Lactase deficiency is the most common intestinal enzyme deficiency. The once popular lactose tolerance test is lately giving way to the breath hydrogen test, which generally reflects unabsorbed carbohydrate reaching the colon. This test and its clinical usefulness are reviewed in some detail, and the use of lactulose as an indicator of intestinal transit is also discussed.

Assessment of orocoecal transit time by means of a hydrogen (H2) breath test as compared with a radiologic control method

The definition of the orocoecal transit time by means of the hydrogen (H2) breath test is not unequivocal. In this study the orocoecal transit time as measured with an H2 breath test was compared with that obtained with a radiologic method. Two definitions of orocoecal transit time by the H2 breath test were evaluated: the time from eating to the first of three consecutively rising H2 values, and the interval to H2 values 50% above 'small-bowel level'. Transit times measured in accordance with both definitions were closely correlated to that obtained with the radiologic method (A, r = 0.84; B, r = 0.90; for both, p less than 0.001), but transit time measured by definition A gave shorter values than the radiologic method (p less than 0.05). The mean transit time in patients with constipation was significantly longer than that in normal subjects and patients with functional diarrhoea (p less than 0.05). There was a significant correlation between the difference in transit time measured with the H2 breath test and the radiologic method and the transit time measured by the control method. This may indicate that rapid transit is associated with a delayed 'colonic' rise in H2 levels and slow transit with an early H2 rise.

Enzyme substitution in chronic pancreatitis: effects on clinical and functional parameters and on the hydrogen (H2) breath test

Ten patients with chronic pancreatitis (with abdominal pain and/or diarrhoea) were treated in a double-blind multiple cross-over trial with Pankreon granules 20 g per day or placebo during three periods of one month each. Pain and bowel habits were recorded. Faecal fat and breath hydrogen (H2) excretion were analyzed during the last days of each treatment period. The pain score was initially low in all patients and was not affected by enzymes. The number of daily bowel movements was reduced from 3.16 to 2.32 (n.s.). Faecal fat excretion per 72 hrs was reduced from 357 +/- 158 mmol free fatty acid to 226 +/- 98 mmol (p less than 0.05). With placebo treatment H2 excretion (from 60 and 180 min after a standard breakfast) was significantly increased compared with 19 healthy volunteers (p less than 0.05). It was not significantly reduced by enzymes. In 28 comparisons the H2 output between 60 and 180 min was correlated to faecal fat. In eight patients the oro-coecal transit-time could be determined by the H2 breath test. The transit-time did not differ from that of ten healthy volunteers and remained unchanged by enzymes. Carbohydrate maldigestion occurs parallel to fat maldigestion in chronic pancreatitis, and is not sufficiently reduced by 20 g of pancreatic enzymes.

The hydrogen (H2) breath test. Sampling methods and the influence of dietary fibre on fasting level

Three end-expiratory breath hydrogen (H2) sampling methods were compared in a patient group (n = 12) and a laboratory staff group (n = 12) on two separate occasions. H2 samples obtained with each method showed significantly different concentrations (p less than 0.001) but no significant differences in coefficient of variation when individual triplicate samples were evaluated. There was a high correlation between the breath H2 concentrations obtained by the three methods (r = 0.93-0.96). Fasting breath H2 values after an overnight fast and an unrestricted diet the day before the investigation were compared with values obtained after an overnight fast and a low-fibre diet the day before the test in two patient groups (n = 39 and 39) with a comparable distribution of diagnoses and in one group of healthy volunteers (n = 17). Fasting breath H2 concentrations were significantly lower after a low-fibre diet in the patient groups (p less than 0.005) and in healthy volunteers (p less than 0.02). We conclude that each of the three end-expiratory sampling methods can be chosen for use in H2 breath tests depending on suitability and convenience and that a low-fibre diet the day before the H2 breath test lowers fasting breath H2 concentration.