Hala M.T. El-Zimaity

Bismuth-Based Quadruple Therapy Using a Single Capsule of Bismuth Biskalcitrate, Metronidazole, and Tetracycline Given With Omeprazole Versus Omeprazole, Amoxicillin, and Clarithromycin for Eradication of Helicobacter pylori in Duodenal Ulcer Patients: A Prospective, Randomized, Multicenter, North American Trial

OBJECTIVES:This multicenter, randomized, active-controlled trial assessed efficacy of bismuth-based quadruple therapy with omeprazole, bismuth biskalcitrate, metronidazole, and tetracycline (OBMT) using a single-triple capsule of BMT compared with triple therapy with omeprazole, amoxicillin, and clarithromycin (OAC) in treatment of patients with Helicobacter pylori infection and duodenal ulcers.METHODS:Patients with active duodenal ulcer or diagnosed within the past 5 yr and with infection documented by 13C-urea breath test plus histology or culture were randomly assigned to 10-day course of OBMT using a single-triple capsule containing bismuth biskalcitrate 140 mg, metronidazole 125 mg, and tetracycline 125 mg given as three capsules q.i.d. with omeprazole 20 mg b.i.d., or a 10-day course of OAC, omeprazole 20 mg plus amoxicillin 1 g plus clarithromycin 500 mg, all b.i.d. Eradication was confirmed by two negative urea breath tests at >1 month and >2 months after therapy.RESULTS:One hundred thirty-eight patients received OBMT and 137 OAC. Modified intent-to-treat eradication rates were 87.7% for OBMT and 83.2% for OAC (95% CI = −3.9%–12.8%; p = 0.29). OBMT eradicated 91.7% metronidazole-sensitive and 80.4% metronidazole-resistant strains (p = 0.06). OAC eradicated 92.1% clarithromycin sensitive and 21.4% clarithromycin-resistant strains (p < 0.001). Adverse events occurred in 58.5% of OBMT patients and 59.0% of OAC patients.CONCLUSIONS:OBMT regimen using the single-triple capsule is as efficacious and well-tolerated as the widely used OAC regimen for H. pylori eradication. This OBMT therapy largely overcomes H. pylori metronidazole resistance, present in 40% of patients in this study.

Mycobacterium avium subsp. paratuberculosis as one cause of Crohn’s disease

A number of theories regarding the aetiology of Crohn’s disease have been proposed. Diet, infections, other unidentified environmental factors and immune disregulation, all working under the influence of a genetic predisposition, have been viewed with suspicion. Many now believe that Crohn’s disease is a syndrome caused by several aetiologies. The two leading theories are the infectious and autoimmune theories. The leading infectious candidate is Mycobacterium avium subspecies paratuberculosis (Mycobacterium paratuberculosis), the causative agent of Johne’s disease, an inflammatory bowel disease in a variety of mammals including cattle, sheep, deer, bison, monkeys and chimpanzees. The evidence to support M. paratuberculosis infection as a cause of Crohn’s disease is mounting rapidly. Technical advances have allowed the identification and/or isolation of M. paratuberculosis from a significantly higher proportion of Crohn’s disease tissues than from controls. These methodologies include: (i) improved culture techniques; (ii) development of M. paratuberculosis‐specific polymerase chain reaction assays; (iii) development of a novel in situ hybridization method; (iv) efficacy of macrolide and anti‐mycobacterial drug therapies; and (v) discovery of Crohn’s disease‐specific seroreactivity against two specific M. paratuberculosis recombinant antigens. The causal role for M. paratuberculosis in Crohn’s disease and correlation of infection with specific stratification(s) of the disorder need to be investigated. The data implicating Crohn’s as an autoimmune disorder may be viewed in a manner that supports the mycobacterial theory. The mycobacterial theory and the autoimmune theory are complementary; the first deals with the aetiology of the disorder, the second deals with its pathogenesis. Combined therapies directed against a mycobacterial aetiology and inflammation may be the optimal treatment of the disease.

Helicobacter pylori outer membrane proteins and gastroduodenal disease

Background and aims: A number of Helicobacter pylori outer membrane proteins (OMPs) undergo phase variations. This study examined the relation between OMP phase variations and clinical outcome. Methods: Expression of H pylori BabA, BabB, SabA, and OipA proteins was determined by immunoblot. Multiple regression analysis was performed to determine the relation among OMP expression, clinical outcome, and mucosal histology. Results:H pylori were cultured from 200 patients (80 with gastritis, 80 with duodenal ulcer (DU), and 40 with gastric cancer). The most reliable results were obtained using cultures from single colonies of low passage number. Stability of expression with passage varied with OipA > BabA > BabB > SabA. OipA positive status was significantly associated with the presence of DU and gastric cancer, high H pylori density, and severe neutrophil infiltration. SabA positive status was associated with gastric cancer, intestinal metaplasia, and corpus atrophy, and negatively associated with DU and neutrophil infiltration. The Sydney system underestimated the prevalence of intestinal metaplasia/atrophy compared with systems using proximal and distal corpus biopsies. SabA expression dramatically decreased following exposure of H pylori to pH 5.0 for two hours. Conclusions: SabA expression frequently switched on or off, suggesting that SabA expression can rapidly respond to changing conditions in the stomach or in different regions of the stomach. SabA positive status was inversely related to the ability of the stomach to secrete acid, suggesting that its expression may be regulated by changes in acid secretion and/or in antigens expressed by the atrophic mucosa.

Challenge model for Helicobacter pylori infection in human volunteers

Background: A reliable challenge model is needed to evaluate Helicobacter pylori vaccine candidates. Methods: A cag pathogenicity island negative, OipA positive, multiple antibiotic susceptible strain of H pylori obtained from an individual with mild gastritis (Baylor strain 100) was used to challenge volunteers. Volunteers received 40 mg of famotidine at bedtime and 104–1010 cfu of H pylori in beef broth the next morning. Infection was confirmed by 13C urea breath test (13C-UBT), culture, and histology. Eradication therapy was given four or 12 weeks post challenge and eradication was confirmed by at least two separate UBTs, as well as culture and histology. Results: Twenty subjects (nine women and 11 men; aged 23–33 years) received a H pylori challenge. Eighteen (90%) became infected. Mild to moderate dyspeptic symptoms occurred, peaked between days 9 and 12, and resolved. Vomitus from one subject contained >103 viable/ml H pylori. By two weeks post challenge gastric histology showed typical chronic H pylori gastritis with intense acute and chronic inflammation. The density of H pylori (as assessed by cfu/biopsy) was similarly independent of the challenge dose. A minimal infectious dose was not found. Gastric mucosal interleukin 8 levels increased more than 20-fold by two weeks after the challenge. Conclusion: Challenge reliably resulted in H pylori infection. Infection was associated with typical H pylori gastritis with intense polymorphonuclear cell infiltration and interleukin 8 induction in gastric mucosa, despite absence of the cag pathogenicity island. Experimental H pylori infection is one of the viable approaches to evaluate vaccine candidates.

Studies Regarding the Mechanism of False Negative Urea Breath Tests With Proton Pump Inhibitors

OBJECTIVE:The mechanism of false negative urea breath tests (UBTs) results among proton pump inhibitor (PPI) users is unknown. We studied the time course of PPI-associated negative UBT, the relation to Helicobacter pylori density, and whether gastric acidification would prevent false negative UBT results.METHOD:In the UBT experiment, H. pylori–infected volunteers received omeprazole 20 mg b.i.d. for 13.5 days. UBTs with citric acid were done before, after 6.5 days of PPI, and 1, 2, 4, 7, and 14 days after therapy. In the culture and histology experiment, after a wash-out of >5 months, nine of the original subjects were rechallenged with omeprazole for 6.5 days. Antral and corpus biopsies for histology and culture were done before and 1 day after PPI administration.RESULTS:Thirty subjects (mean age 42 yr) were enrolled. UBTs were significantly reduced on day 6.5 (p = 0.031); 10 subjects (33%) developed transient negative UBTs. The UBT recovered in all but one subject by the fourth day post-PPI and in all subjects by day 14. In the culture and histology experiment, upon PPI rechallenge, three of nine subjects (33%) had negative UBTs. H. pylori density, whether measured by culture or histology, decreased with PPI therapy; antral biopsies became histologically negative in five subjects and corpus biopsies in three subjects.CONCLUSION:PPI-induced negative UBT results were related to the anti-H. pylori effect of the PPI. Acidification of the stomach did not prevent false negative UBT results. Three days is likely the minimum delay from stopping PPI until one should perform a test for active infection. A delay of 14 days is preferred.

Detection of Mycobacterium avium subspecies paratuberculosis in Crohn's diseased tissues by in situ hybridization.

OBJECTIVES:Reports about the association between Crohns disease (CD) and cell wall-deficient (CWD) forms of Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) are controversial. This may be due to the heterogeneous nature of CD where only about 50% of the patients show granulomatous inflammation. Detection of CWD forms of M. paratuberculosis in tissues from patients with CD would support its association with the disease. To help identify these forms in inflamed tissues, a previously developed and optimized nonradioactive in situ hybridization method was applied on well-defined tissue materials obtained from patients with CD, ulcerative colitis (UC), and controls.METHODS:Specimens from 37 patients with CD (15 with epitheloid cell granulomas and 22 without granulomas), 21 UC, and 22 noninflammatory bowel disease (IBD) patients were analyzed by the in situ hybridization method based on the digoxigenin-labeled M. paratuberculosis IS900 fragment, previously shown to be species specific. Samples were counterstained with hematoxylin and eosin to show the location of the positive signal. Positive controls made of beef cubes injected with CWD and acid-fast M. paratuberculosis and negative controls were included in each experiment to monitor for nonspecific hybridization or staining.RESULTS:Six of 15 (40%) patients with CD and granulomas showed positive signals in myofibroblasts and macrophages. Interestingly, no positive signals were observed within granulomas. Only 4.5% of 22 CD samples from patients with nongranulomatous disease, 9.5% of 21 UC, and remarkably, none of the 22 non-IBD patients were M. paratuberculosis positive.Conclusion:The demonstration of DNA from CWD forms of M. paratuberculosis in this limited number of CD tissues further supports and confirms previous reports of its association with the granulomatous type of the disease.

Evaluation of gastric mucosal biopsy site and number for identification of Helicobacter pylori or intestinal metaplasia: Role of the sydney system

Pathologists are frequently asked to evaluate gastric mucosal biopsy specimens for the presence of Helicobacter pylori infection and for potentially important changes such as intestinal metaplasia. No agreed-on system is both available and prospectively shown to provide reliable estimates of the underlying pathological condition. The Sydney System combined topographical, morphological, and causative information for evaluation of gastric biopsy specimens and provided recommendations regarding biopsy site and number. Both the biopsy sites and number were changed in 1994. Gastric biopsy specimens from patients who had multiple biopsies performed on predetermined sites were examined to compare the original and the revised Sydney Systems for the detection of intestinal metaplasia and H pylori. The diagnosis based on both versions of the Sydney System was then compared with that obtained by evaluating all specimens. Forty-six patients were studied, 20 with H pylori infection and 36 with intestinal metaplasia. Using either version of the Sydney System correctly categorized H pylori infection status in 100%. Both the original and the revised Sydney recommendations seriously underestimated the prevalence of intestinal metaplasia. Intestinal metaplasia was missed in more than 50% of those with confirmed intestinal metaplasia. No set or site of biopsy specimens was found that could reliably exclude the presence of intestinal metaplasia. Current and future studies that use the Sydney System as basis for detecting intestinal metaplasia are not likely to be reliable. Likewise, using the Sydney System to test posttherapy or with time will not accurately reflect the true status of intestinal metaplasia.

Isolation of Helicobacter pylori From Sheep—Implications for Transmission to Humans

OBJECTIVES:When and how Helicobacter pylori (H. pylori) originally entered the human population as well as how the infection is transmitted in different communities is unknown. We previously showed that Sardinian shepherds had almost a 100% prevalence of H. pylori and that the prevalence was higher than that of their same-household siblings.Aim:To examine whether H. pylori infection might be transmitted from sheep.METHODS:Milk and gastric tissue were cultured and analyzed by PCR amplification using three sets of primers Helicobacter genus–specific 16S rRNA and two sets of primers specific for H. pylori vacA gene.RESULTS:Helicobacter DNA was demonstrated in 60% (38/63) of milk samples and in 30% (6/20) of sheep tissue samples. H. pylori vacA gene was amplified in five of 38 milk samples, and in two of six sheep tissue samples respectively. H. pylori were cultured from sheep milk and tissue samples and confirmed as H. pylori on the basis of colony morphology, positive biochemical reactions, and negative Gram stain. Sequence analysis of 16S rRNA PCR products from these isolates demonstrated 99% identity with H. pylori.CONCLUSIONS:Together, the presence of H. pylori in sheep stomach in the absence of associated gastritis and recovery of H. pylori from sheep milk and gastric tissue suggest that sheep may be a natural host for H. pylori.

Cytokeratin subsets for distinguishing barrett's esophagus from intestinal metaplasia in the cardia using endoscopic biopsy specimens

OBJECTIVES:It has been suggested that Barretts epithelium and intestinal metaplasia in the gastric cardia have different cyotokeratin (CK) staining patterns and that Barretts epithelium can be distinguished by CK staining pattern. The aim of this study was to test the utility of CK staining for distinguishing Barretts esophagus from gastric intestinal metaplasia.METHODS:Topographically mapped gastric biopsy specimens were obtained from patients without Barretts esophagus, and esophageal biopsies were obtained from patients with long-segment Barretts esophagus (>3 cm). Serial sections were stained with Genta or El-Zimaity triple stain, and biopsies with intestinal metaplasia were stained with antibodies against CK 4, 13, 7, and 20.RESULTS:Sections from 33 biopsies with Barretts esophagus, 23 with intestinal metaplasia of the gastric cardia, 27 with intestinal metaplasia of the gastric body, and 33 with intestinal metaplasia of the antrum were examined. CK 4 and CK 13 stained squamous epithelium only. The proposed “diagnostic” CK Barretts 7/20 pattern was found in only 39% of long-segment Barretts compared to 35%, 4%, and 24% in intestinal metaplasia from the gastric cardia, body, and antrum, respectively. The criteria proposed had a sensitivity of 45% and a specificity of 65%.CONCLUSIONS:These results do not support keratin phenotyping as a tool for differentiating intestinal metaplasia originating in the cardia from intestinal metaplasia of Barretts.

Metronidazole, omeprazole and clarithromycin: An effective combination therapy for Helicobacter pylori infection

Background: Successful treatment of Helicobacter pylori infection results in cure of peptic ulcer disease. Multidrug regimens are needed to cure this infection. We studied the effectiveness and side effect profile of two antibiotics active against Helicobacter pylori, metronidazole and clarithromycin, combined with omeprazole.