Effect of nizatidine 300 mg at night and omeprazole 20 mg in the morning on 24-hour intragastric pH and bacterial overgrowth in patients with acute duodenal ulcer

Colonization by Pseudomonas aeruginosa and Staphylococcus aureus of Antral Biopsy Specimens from Gastritis Patients Uninfected with Helicobacter Pylori

Purpose

Roles and incidence of some microorganisms that transiently or permanently colonize the human stomach are still unknown despite advances in gastroenterology. We aimed to examine the incidence of four microorganisms, Helicobacter pylori, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis, in the antral biopsy specimens of patients with gastroduodenal conditions.

Patients and Methods

Patients (67 females, 33 males; mean age = 49.5 years) were initially examined and diagnosed by a gastroenterologist at the Mehrad Hospital, Tehran, Iran. We enrolled those who underwent the upper gastrointestinal endoscopy because of gastroduodenal conditions. Two antral biopsy samples were taken by endoscopy; the first sample was used for the “rapid urease test” to confirm H. pylori. The second was used for DNA extraction and PCR analyses with specific, corresponding primer sets to establish the presence of the four microorganisms. Our study was approved by the Ethics Committee at the Tarbiat Modares University, Tehran.

Results

Based on pathology and endoscopy findings, we divided the patients into three groups: 62 presented with gastritis, 18 with duodenal ulcer, and 20 gastric ulcer. The number of patients with P. aeruginosa but without H. pylori significantly differed from the number of those co-infected with both microorganisms (P = 0.03). Additionally, a similar significance was found between the incidence of S. aureus in patients without H. pylori and those with both infections (P = 0.04). Our results indicated that a significant number of patients with gastritis were colonized with P. aeruginosa or S. aureus without being co-infected with H. pylori (P < 0.001). Interestingly, the incidence of colonization by P. aeruginosa of patients without H. pylori (45/49, 91.8%) was higher than that by S. aureus (28/49, 57%).

Conclusion

The number of patients without H. pylori but with P. aeruginosa or with S. aureus infection significantly differed from that with both infections, respectively. Our study thus shows that patients without H. pylori infection are prone to be colonized by P. aeruginosa or S. aureus, indicating that targeted antibiotic regimens are necessary for clinically treating them.

Bacterial flora concurrent with Helicobacter pylori in the stomach of patients with upper gastrointestinal diseases

AIM: To investigate the non-Helicobacter pylori (H. pylori) bacterial flora concurrent with H. pylori infection.

METHODS: A total of 103 gastric biopsy specimens from H. pylori positive patients were selected for bacterial culture. All the non-H. pylori bacterial isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).

RESULTS: A total of 201 non-H. pylori bacterial isolates were cultivated from 67 (65.0%) of the 103 gastric samples, including 153 isolates identified successfully at species level and 48 at genus level by MALDI-TOF MS. The dominant species were Streptococcus, Neisseria, Rothia and Staphylococcus, which differed from the predominantly acid resistant species reported previously in healthy volunteers. The prevalence of non-H. pylori bacteria was higher in non-ulcer dyspepsia group than in gastric ulcer group (100% vs 42.9%, P < 0.001). Six bacterial species with urease activity (Staphylococcus epidermidis, Staphylococcus warneri, Staphylococcus capitis, Staphylococcus aureus, Brevibacterium spp. and Klebsiella pneumoniae) were also isolated.

CONCLUSION: There is a high prevalence of the non-H. pylori bacteria concurrent with H. pylori infection, and the non-H. pylori bacteria may also play important as-yet-undiscovered roles in the pathogenesis of stomach disorders.

Risk of community-acquired pneumonia in veteran patients to whom proton pump inhibitors were dispensed

BACKGROUND

Observational studies linking proton pump inhibitor (PPI) exposure with community-acquired pneumonia (CAP) have reported either modest or no associations. Accordingly, we studied PPI exposure and CAP in veteran patients, using a retrospective, nested case-control design.

METHODS

From linked pharmacy and administrative databases of the New England Veterans Healthcare System, we identified 71985 outpatients newly prescribed PPIs between 1998 and 2007; 1544 patients met criteria for CAP subsequent to PPI initiation; 15440 controls were matched through risk-set sampling by age and time under observation. Crude and adjusted odds ratios comparing current with past PPI exposures, as well as tests for interactions, were conducted for the entire and stratified samples.

RESULTS

Current PPI use associated with CAP (adjusted odds ratio [OR], 1.29 [95% confidence interval {CI}, 1.15-1.45]). Risks were not substantially altered by age or year of diagnosis. Dementia (n = 85; P = .062 for interaction) and sedative/tranquilizer use (n = 224; P = .049 for interaction) were likely effect modifiers increasing a PPI-CAP association; conversely, for some chronic medical conditions, PPI-associated CAP risks were reversed. PPI exposures between 1 and 15 days increased CAP risks, compared with longer exposures, but PPI initiation also frequently occurred shortly after CAP diagnoses. Prescribed PPI doses >1 dose/day also increased PPI-associated CAP risks.

CONCLUSIONS

Among the veterans studied, current compared with past PPI exposures associated modestly with increased risks of CAP. However, our observations that recent treatment initiation and higher PPI doses were associated with greater risks, and the inconsistent PPI-CAP associations between patient subgroups, indicate that further inquiries are needed to separate out coincidental patterns of associations.

Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough

BACKGROUND

Nocturnal gastric acid breakthrough (NAB) is defined as intragastric pH<4 for more than one continuous hour overnight. Adding H(2)-receptor antagonists (H2RAs) at bedtime to high-dose proton pump inhibitors is likely to enhance nocturnal gastric pH control and decrease nocturnal gastric acid breakthrough.

OBJECTIVES

To assess the effectiveness of additional bedtime H2-receptor antagonists in suppressing nocturnal gastric acid breakthrough and the incidence of adverse effects.

SEARCH STRATEGY

We identified eligible trials by searching The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2008), MEDLINE (1966-August 2008), EMBASE (1980-August 2008) and CINAHL (1982-August 2008). We re-ran the search on CENTRAL (The Cochrane Library Issue 4, 2008), and in MEDLINE, EMBASE and CINAHL in June 2004, July 2005, August 2006 and August 2008.

SELECTION CRITERIA

All randomized controlled trials evaluating H2-receptor antagonists for the control of nocturnal gastric acid breakthrough were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two reviewers have independently selected the trials to be included in the review according to the pre-stated eligibility criteria. Disagreements were resolved by a third reviewer. If the data could not be pooled for meta-analysis, a narrative description was provided.

MAIN RESULTS

8 small randomized controlled trials were included for meta-analysis. The results show that additional bedtime H2RAs can decrease the prevalence rate of nocturnal gastric acid breakthrough. The results of the analyses for secondary outcomes show that additional bedtime H2RAs can decrease the percentage of time during which pH is less than 4.0 inside the stomach and promote median intragastric pH.

AUTHORS' CONCLUSIONS

We can conclude no implications for practice at this stage. Appropriately designed large-scale randomized controlled trials with long-term follow-up are needed to determine the effects of additional bedtime H2RAs in suppressing nocturnal gastric acid breakthrough.

Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough: a Cochrane systematic review

OBJECTIVES

To assess the effectiveness and safety of additional bedtime H(2)-receptor antagonists (H(2)RAs) in suppressing nocturnal gastric acid breakthrough (NAB) via a systematic review.

METHODS

Eligible trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 2, 2004), MEDLINE (January 1966-June 2004), EMBASE (January 1980-June 2004) and CINAHL (January 1982-June 2004). Additional hand-searching was conducted on the proceedings of correlated conferences, eight important Chinese journals and references of all included trials. All randomized controlled trials evaluating H(2)RAs for the control of NAB were eligible for inclusion. The systematic review was conducted using methods recommended by The Cochrane Collaboration.

RESULTS

Only two randomized crossover studies, comprising 32 participants, met the inclusion criteria. Because the design, dosage and duration of the treatments were different between the studies, it was not possible to conduct meta-analysis. There were no consistent conclusions found between the two included studies in evaluating H(2)RAs for the control of NAB.

CONCLUSIONS

No implications for practice at this stage can be concluded. Appropriately designed large-scale randomized controlled trials with long-term follow up are needed to determine the effects of additional bedtime H(2)RAs in suppressing NAB.

Experimental model in the qualitative and quantitative assessment of non-Helicobacter gastric microflora under proton pump inhibitors action

PURPOSE

To evaluate models of gastric material collection from Wistar rats with and without using proton pump inhibitors(PPIs).

METHODS

Twenty-four rats underwent intraperitoneal omeprazol treatment, and other 12 received similar treatment with 0.9% saline. All animals underwent collection of gastric material samples, after stomach removal, by either biopsies, or aspirates, or swabs. Samples were bacteriologically processed in order to identify species and strains. Values are described as natural logarithm of colony former units per mL [Ln(CFU/mL)]. Kruskal-Wallis and Mann-Whitney non-parametric tests were used, and p<0.05 was set as statistically significant.

RESULTS

Significant difference was not seen for Ln (UFC/mL) values among the three methods of collection irrespective of using or not omeprazol. Also, significant difference was not seen in Ln (UFC/mL) values when comparing a method with each others, either using omeprazol or placebo. A significant increase of bacteria strains occurred when PPI was used, and this was seen on the three ways of collection, mainly in biopsy and swab.

CONCLUSION

No difference occurred among the three methods of collecting bacteria samples from stomachs of rats, either when using placebo or omeprazol. A remarkable change is seen on animals bacterial microflora when PPIs are used, and bacteria are better identified when swab and biopsy are used.

The pathogenesis of gastrointestinal bacterial overgrowth

The normal indigenous intestinal microflora consists of about 10(15) bacteria that under physiological conditions reside mainly in the lower gastrointestinal tract. Bacterial overgrowth implies abnormal bacterial colonization of the upper gut, resulting from failure of specific defense mechanisms restricting colonization under physiological conditions. At present two types of bacterial overgrowth with defined pathogenesis can be distinguished: (1) gastric overgrowth with upper respiratory tract microflora resulting from selective failure of the gastric acid barrier, and (2) gastrointestinal overgrowth with Gram-negative bacilli (enteric bacteria) resulting from failure of intestinal clearance. Helicobacter pylori-induced gastritis of the oxyntic mucosa is the main cause of acquired failure of the gastric acid barrier, which is common among the healthy elderly. Intestinal clearance may fail as the result of impaired intestinal peristalsis or anatomical abnormalities that alter luminal flow. Impaired peristalsis is associated with conditions interfering with intestinal neuromuscular function including myopathic, neuropathic, autoimmune, infectious, inflammatory, metabolic, endocrine, and neoplastic diseases. Anatomical abnormalities are mainly the result of gastrointestinal surgery, intestinal diverticula or fistula. Combined failure of intestinal clearance and the gastric acid barrier results in more severe colonization with Gram-negative bacilli. Gram-negative bacilli are uncommon in the upper gut of otherwise healthy individuals with gastric hypochlorhydria, being acquired (H. pylori) or drug-induced. Significant bacterial overgrowth with Gram-negative bacilli is a rational in the search for an explanation to optimize clinical management. The clinical significance of colonization with upper respiratory tract microflora remains unclear. Translocation of live bacteria, their metabolic products, or antigens from a small bowel colonized by Gram-negative bacilli play a role in the pathogenesis of spontaneous bacterial peritonitis in hepatic disease and in certain types of sepsis, indicating that further studies can point to new patient populations with potential benefit from medical treatment.

Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough

BACKGROUND

Nocturnal gastric acid breakthrough(NAB) is defined as intragastric pH<4 for more than one continuous hour overnight. Adding H2-receptor antagonists (H2RAs)at bedtime to high-dose proton pump inhibitors is likely to enhance nocturnal gastric pH control and decrease nocturnal gastric acid breakthrough.

OBJECTIVES

To assess the effectiveness of additional bedtime H2-receptor antagonists in suppressing nocturnal gastric acid breakthrough and the incidence of adverse effects.

SEARCH STRATEGY

We identified eligible trials by searching The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2003), MEDLINE (1966-July 2003), EMBASE (1980-July 2003) and CINAHL (1982-July 2003). We re-ran the search on CENTRAL (The Cochrane Library Issue 2, 2004), and in MEDLINE, EMBASE and CINAHL in June 2004.

SELECTION CRITERIA

All randomized controlled trials evaluating H2-receptor antagonists for the control of nocturnal gastric acid breakthrough were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We extracted data and recorded relevant information onto specially developed forms. One reviewer extracted data and a second reviewer checked data extraction. We have also double-checked data entry into RevMan. For binary outcomes, we expressed the impact of the intervention as relative risks, together with 95% confidence intervals. For scale-based outcomes, we used means and standard deviations to summarise the values in each group, provided the scale permitted sufficient values. We had intended to analyse such outcomes for the presence of skew, but the studies included were too limited to permit this.

MAIN RESULTS

Two randomized crossover studies including 32 participants met the inclusion criteria. Because the design, dosage and duration of the treatment were different between the studies, it was not possible to conduct meta-analysis. There is no consistent conclusion between the two included studies in evaluating H2RAs for the control of NAB.

REVIEWERS' CONCLUSIONS

We can conclude no implications for practice at this stage. Appropriately designed, large-scale randomized controlled trials with long-term follow-up are needed to determine the effects of additional bedtime H2RAs in suppressing nocturnal gastric acid breakthrough.

Gastric acid-suppressive therapy and community-acquired respiratory infections

BACKGROUND

Bacteria and viruses have been detected in the stomach of patients during acid-suppressive therapy.

AIM

To investigate whether subjects using acid-suppressive drugs more often develop community-acquired respiratory infections when compared to those who do not use acid-suppressive drugs.

METHODS

700 study subjects were recruited during a single week in December 2002. Information on the prevalence of clinical manifestations of infections and complications in the preceding month was assessed by questionnaire. Furthermore, subjects were asked to report antibiotic therapy and physician visits related to possible infection.

RESULTS

Questionnaires were returned by 405 subjects (58%). Consumption of acid-suppressive drugs was reported by 91 individuals, of whom 79 used proton-pump inhibitors (20%) and 12 H2-receptor antagonists (3%). Overall, 101 (25%) responders reported clinical manifestations of respiratory infection in the preceding month. Subjects using acid-suppressive drugs were 2.34 times [95% confidence interval (CI) 1.4-4.1] more likely to have clinical manifestations of infection than individuals not using acid-suppressive drugs. Subjects using acid-suppressive drugs visited a physician 3.72 times more often (95% CI 2.1-6.8) for an infection and received antibiotic therapy 4.19 times more often (95% CI 2.2-8.1) in comparison to individuals not using acid-suppressive drugs.

CONCLUSIONS

Subjects using acid-suppressive drugs more often reported community-acquired respiratory infections in comparison to those who did not use acid-suppressive drugs.

Intragastric volatile N-nitrosamines, nitrite, pH, and Helicobacter pylori during long-term treatment with omeprazole

BACKGROUND & AIMS

This study evaluated the effect of long-term gastric acid suppressive therapy with omeprazole on intragastric levels of carcinogenic N-nitrosamines and related parameters.

METHODS

Forty-five patients on long-term omeprazole medication (mean, 35 months) and 13 healthy subjects without medication participated. Volatile N-nitrosamines were determined in gastric juice and urine. Intragastric pH, nitrite, nitrate, and H. pylori status were determined. DNA isolated from gastric biopsy specimens was analyzed for precarcinogenic alkyl-DNA adducts.

RESULTS

The intragastric pH in patients was significantly higher compared with controls (P = 0.0001). Gastric nitrite levels in patients were nonsignificantly higher. There was no difference in total levels of intragastric volatile N-nitrosamines between patients and controls, however, urinary N-nitrosodimethylamine excretion was higher in patients (P = 0.001). On omeprazole, Helicobacter pylori-positive vs. -negative patients had a nonsignificantly higher intragastric nitrite level and higher urinary N-nitrosodimethylamine excretion. No alkyl-DNA adducts could be detected in gastric epithelium.

CONCLUSIONS

Increased intragastric pH caused by long-term treatment with omeprazole does not result in increased intragastric levels of nitrite and volatile N-nitrosamines. The significantly higher urinary N-nitrosamine excretion implies the risk of increased endogenous formation of N-nitrosamines during long-term omeprazole treatment. This risk may be higher in H. pylori-positive patients.

Non-Helicobacter pylori bacterial flora during acid-suppressive therapy: differential findings in gastric juice and gastric mucosa

BACKGROUND

Intragastric growth of non-Helicobacter pylori bacteria commonly occurs during acid-suppressive therapy. The long-term clinical consequences are still unclear.

AIM

To investigate the luminal and mucosal bacterial growth during gastric acid inhibition, in relation to the type and duration of acid-inhibitory treatment, as well as to concomitant H. pylori infection.

METHODS

A total of 145 patients on continuous acid inhibition with either proton pump inhibitors (n=109) or histamine2-receptor antagonists (H(2)RAs, n=36) for gastro-oesophageal reflux disease, and 75 dyspeptic patients without acid inhibition (control group) were included. At endoscopy, fasting gastric juice was obtained for pH measurement and bacteriological culture. Gastric biopsy specimens were examined for detection of H. pylori (immunohistochemistry) and of non-H. pylori bacteria (modified Giemsa stain-positive and immunohistochemistry-negative at the same location).

RESULTS

Non-H. pylori flora was detected in the gastric juice of 92 (41.8%) patients and in the gastric mucosa of 109 (49.6%) patients. In gastric juice, prevalence rate for non-H. pylori bacteria was higher in patients taking proton pump inhibitors than controls and those taking H(2)RAs (58.7% vs. 22.6% and vs. 30.6%, P < 0.0001 and P < 0.003, respectively), but did not differ statistically between H(2)RAs and controls. In gastric mucosa, prevalence rates for non-H. pylori bacteria were higher in patients taking proton pump inhibitors and H(2)RAs than in the controls (antrum: 46.9% and 48.6% vs. 25%, P < 0.05 for both; corpus: 52.2% and 56.8% vs. 23.7%, P < 0.001 for both), but did not differ between proton pump inhibitors and H(2)RAs. Both luminal and mucosal growth of non-H. pylori bacteria were significantly greater in H. pylori-positive than -negative patients taking proton pump inhibitors (P < 0.05 for both). Luminal growth of non-H. pylori flora increased with the intragastric pH level, whilst mucosal bacterial growth increased with the duration of acid inhibition.

CONCLUSIONS

Non-H. pylori flora not only contaminates the gastric juice but also colonizes the gastric mucosa of a large proportion of patients treated long-term with acid inhibition. The relationship between H. pylori and non-H. pylori bacteria in the pathogenesis of atrophic gastritis and gastric cancer needs further elucidation.