Alternative and rescue treatment regimens for Helicobacter pylori eradication

The mechanisms of metronidazole resistance of Helicobacter pylori: A transcriptomic and biochemical study

Helicobacter pylori (H. pylori) is a bacterial pathogen in the stomach, causing gastritis, gastric ulcer, duodenal ulcer and even gastric cancer. The triple therapy containing one bismuth-containing compound or a proton-pump inhibitor with two antibiotics was the cornerstone of the treatment of H. pylori infections. However the drug resistance of Helicobacter pylori is more and more common, which leads to the continued decline in the radical cure rate. The purpose of this study was to investigate the mechanism of metronidazole resistance of H. pylori through transcriptomics and biochemical characterizations. In this study, a 128-time-higher metronidazole-resistant H. pylori strain compared to the sensitive strain was domesticated, and 374 significantly differential genes were identified by transcriptomic sequencing as compared to the metronidazole-sensitive strain. Through GO and KEGG enrichment analysis, antibiotic-resistance pathways were found to be mainly involved in redox, biofilm formation and ABC transportation, and the results were verified by qRT-PCR. The subsequent biochemical analysis found that the urease activity of the drug-resistant strain decreased, and whereas the capabilities of bacterial energy production, membrane production and diffusion ability increased. The work here will drop hints for the mechanisms of antibiotic-resistance of H. pylori and provide promising biomarkers for the further development of new-kind drugs to treat metronidazole-resistant H. pylori.

Helicobacter pylori eradication with ecabet sodium, omeprazole, amoxicillin, and clarithromycin versus bismuth, omeprazole, amoxicillin, and clarithromycin quadruple therapy: a randomized, open-label, phase IV trial

BACKGROUND

Helicobacter pylori infection is a substantial public health problem and plays etiological role in the pathogenesis of many gastroduodenal disorders. The addition of ecabet sodium is proven to improve the efficacy of the standard triple therapy. Our aim was to assess the efficacy and safety of ecabet sodium-containing quadruple therapy versus 10-day bismuth-containing quadruple therapy for H. pylori eradication.

MATERIALS AND METHODS

We did a randomized, open-label, phase IV trial in four cities (eight sites) in China, comparing the efficacy and safety of 10-days ecabet sodium-containing versus bismuth-containing quadruple therapy in adults with H. pylori infection. Eligible patients were randomly assigned treatment and monitored H. pylori eradication by negative [13C]/[14C] urea breath test 28 days after the treatment as the primary outcome. Symptoms improvement and side effects were the secondary outcome.

RESULTS

A total of 311 H. pylori-positive subjects were enrolled: 155 were assigned ecabet sodium quadruple therapy and 156 bismuth quadruple therapy. The eradication rates with ecabet sodium-containing and bismuth-containing quadruple regimens were 68.4% (106/155) and 68.0% (106/156) p = .9339 intention-to-treat (ITT) and 75.4% (104/138) and 77.0% (104/135) p = .7453 per-protocol (PP), respectively. The eradication rates for the ecabet sodium quadruple regimen differed significantly between cities (e.g., 81.2% ITT and 89.6% PP in Shanghai and 50% ITT and 53.5% PP in Xi'an). The symptom improvements and safety profiles were also similar for both treatments.

CONCLUSIONS

Neither 10-day Ecabet sodium-containing quadruple therapy or 10-day bismuth-containing quadruple therapy can be recommended as empiric therapy in cities with high antibiotic resistance rate of China.

Rescue Therapy for Helicobacter pylori Infection 2012

Helicobacter pylori infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. After 30 years of experience in H. pylori treatment, however, the ideal regimen to treat this infection has still to be found. Nowadays, apart from having to know well first-line eradication regimens, we must also be prepared to face treatment failures. In designing a treatment strategy, we should not only focus on the results of primary therapy alone but also on the final-overall-eradication rate. The choice of a "rescue" treatment depends on which treatment is used initially. If a first-line clarithromycin-based regimen was used, a second-line metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third-line "rescue" option. Alternatively, it has recently been suggested that levofloxacin-based "rescue" therapy constitutes an encouraging 2nd-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, quadruple regimen may be reserved as a 3rd-line "rescue" option. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several "rescue" therapies are consecutively given.

Inhibition of fumarase by bismuth(III): implications for the tricarboxylic acid cycle as a potential target of bismuth drugs in Helicobacter pylori

Helicobacter pylori causes various gastric diseases, such as gastritis, peptic ulcerations and gastric cancer. Triple therapy combining bismuth compounds with two antibiotics is the cornerstone of the treatment of H. pylori infections. Up to now, the molecular mechanisms by which bismuth inhibits the growth of H. pylori are far from clear. In the bacterial tricarboxylic acid (TCA) cycle, fumarase catalyses the reversible hydration of fumarate to malic acid. Our previous proteomic work indicated that fumarase was capable of bismuth-binding. The interactions as well as the inhibitory effects of bismuth to fumarase have been characterized in this study. The titration of bismuth showed that each fumarase monomer binds one mol equiv of Bi(3+), with negligible secondary structural change. Bismuth-binding results in a near stoichiometric inactivation of the enzyme, leading to an apparent non-competitive mechanism as reflected by the Lineweaver-Burk plots. Our collective data indicate that the TCA cycle is a potential molecular target of bismuth drugs in H. pylori.

In vitro antibacterial activity of Phx-3 against Helicobacter pylori

Phx-3, one of the phenoxazine derivatives, is reported to have inhibitory effect on Mycobacterium species and Chlamydia pneumoniae but not Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes. The bactericidal activities of Phx-3 against Helicobacter pylori strains have not been assessed. Then, we measured minimum inhibitory concentration of Phx-3 for Helicobacter strains and assessed the morphological and biochemical effects of Phx-3 on H. pylori. In present study, it has shown that H. pylori strains including clarithromycin resistant strain and Helicobacter musterae were killed effectively by the treatment with Phx-3. Furthermore, severe morphological changes such as membrane blebbing and formation of hollows in H. pylori were detected. In addition, induction of heat shock protein 60 was observed. Taken together, Phx-3 has antibacterial activity against Helicobacter pylori.

Second-line rescue therapy of helicobacter pylori infection

Helicobacter pylori infection is the main known cause of gastritis, gastroduodenal ulcer disease and gastric cancer. After more than 20 years of experience in H. pylori treatment, however, the ideal regimen to treat this infection has still to be found. Nowadays, apart from having to know well first-line eradication regimens, we must also be prepared to face treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final (overall) eradication rate. The choice of a 'rescue' treatment depends on which treatment is used initially. If a first-line clarithromycin-based regimen was used, a second-line metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third-line 'rescue' option. Alternatively, it has recently been suggested that levofloxacin-based 'rescue' therapy constitutes an encouraging second-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, quadruple regimen may be reserved as a third-line 'rescue' option. Finally, rifabutin-based 'rescue' therapy constitutes an encouraging empirical fourth-line strategy after multiple previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several 'rescue' therapies are consecutively given. Therefore, the attitude in H. pylori eradication therapy failure, even after two or more unsuccessful attempts, should be to fight and not to surrender.

Review article: 'true' re-infection of Helicobacter pylori after successful eradication--worldwide annual rates, risk factors and clinical implications

BACKGROUND

The incidence of 'true' re-infection with Helicobacter pylori after successful eradication remains uncertain.

AIM

To determine the worldwide rates, risk factors and clinical implications of 'true' re-infection of Helicobacter pylori. 'True' re-infection of H. pylori is defined as the situation where tests for H. pylori infection, which were negative for 12 months after eradication, become positive again at a later stage.

RESULTS

Thirty six studies were identified through a literature search to be able to produce annual rates of 'true' re-infection, and data from 33 original articles were considered reliable and adequate in the further review. Generally, the reported rates varied from 0% to 23.4% in adults and from 1.9% to 9.6% in children. Most studies from developed countries reported rates of less than 1%, whereas relatively higher rates were reported in most of the developing countries. Small sample sizes included in the studies appeared to be associated with increased re-infection rates. Interfamilial transmission is the major cause of re-infection, although iatrogenic re-infection through contaminated endoscopic equipment has been reported.

CONCLUSION

Helicobacter pylori re-infection is not a concern in a clinical setting, especially in the developed world; however, caution must be exercised in most developing countries.

“Rescue” regimens after Helicobacter pylori treatment failure

Helicobacter pylori (H pylori) infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. After more than 20 years of experience in H pylori treatment, in my opinion, the ideal regimen to treat this infection is still to be found. Currently, apart from having to know first-line eradication regimens well, we must also be prepared to face treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final (overall) eradication rate. The choice of a “rescue” treatment depends on which treatment is used initially. If a clarithromycin-based regimen was used initially, a subsequent metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third “rescue” option. Alternatively, it has recently been suggested that levofloxacin-based rescue therapy constitutes an encouraging second-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, a quadruple regimen may be reserved as a third-line rescue option. Finally, rifabutin-based rescue therapy constitutes an encouraging empirical fourth-line strategy after multiple previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin. Even after two consecutive failures, several studies have demonstrated that H pylori eradication can finally be achieved in almost all patients if several rescue therapies are consecutively given. Therefore, the attitude in H pylori eradication therapy failure, even after two or more unsuccessful attempts, should be to fight and not to surrender.

Treatment of Helicobacter pylori and prevention of gastric cancer

Gastric cancer is the second commonest fatal malignancy in the world with a high incidence in China. Helicobacter pylori infection is an important factor in the pathogenesis of gastric cancer. Epidemiological studies have shown a strong causal relationship between H. pylori infection and gastric cancer. Animal studies also show that eradication of H. pylori infection, especially at the early stage, is effective in preventing H. pylori-related gastric carcinogenesis. H. pylori eradication leads to regression and prevents the progression of gastric precancerous lesions, but only in a minority of cases. H. pylori eradication appears to be the most promising approach in gastric cancer prevention. The current available data in human studies showed that H. pylori eradication can reduce the risk of developing gastric cancer and this strategy is more useful in patients without atrophic gastritis or intestinal metaplasia. A longer follow-up and additional studies are needed for better understanding this issue.

Second-line rescue therapy with levofloxacin after H. pylori treatment failure: a Spanish multicenter study of 300 patients

AIM

Quadruple therapy is generally recommended as second-line therapy after Helicobacter pylori (H. pylori) eradication failure. However, this regimen requires the administration of four drugs with a complex scheme, is associated with a relatively high incidence of adverse effects, and bismuth salts are not available worldwide anymore. Our aim was to evaluate the efficacy and tolerability of a triple second-line levofloxacin-based regimen in patients with H. pylori eradication failure.

DESIGN

Prospective multicenter study.

PATIENTS

in whom a first treatment with proton pump inhibitor-clarithromycin-amoxicillin had failed.

INTERVENTION

A second eradication regimen with levofloxacin (500 mg b.i.d.), amoxicillin (1 g b.i.d.), and omeprazole (20 mg b.i.d.) was prescribed for 10 days.

OUTCOME

Eradication was confirmed with (13)C-urea breath test 4-8 wk after therapy. Compliance with therapy was determined from the interview and the recovery of empty envelopes of medications. Incidence of adverse effects was evaluated by means of a specific questionnaire.

RESULTS

Three hundred consecutive patients were included. Mean age was 48 yr, 47% were male, 38% had peptic ulcer, and 62% functional dyspepsia. Almost all (97%) patients took all the medications correctly. Per-protocol and intention-to-treat eradication rates were 81% (95% CI 77-86%) and 77% (73-82%). Adverse effects were reported in 22% of the patients, mainly including nausea (8%), metallic taste (5%), abdominal pain (3%), and myalgias (3%); none of them were severe.

CONCLUSION

Ten-day levofloxacin-based rescue therapy constitutes an encouraging second-line strategy, representing an alternative to quadruple therapy in patients with previous proton pump inhibitor-clarithromycin-amoxicillin failure, being simple and safe.

Rational prescription of drugs within similar therapeutic or structural class for gastrointestinal disease treatment: Drug metabolism and its related interactions

AIM: To review and summarize drug metabolism and its related interactions in prescribing drugs within the similar therapeutic or structural class for gastrointestinal disease treatment so as to promote rational use of medicines in clinical practice.

METHODS: Relevant literature was identified by performing MEDLINE/Pubmed searches covering the period from 1988 to 2006.

RESULTS: Seven classes of drugs were chosen, including gastric proton pump inhibitors, histamine H₂-receptor antagonists, benzamide-type gastroprokinetic agents, selective 5-HT₃ receptor antagonists, fluoroquinolones, macrolide antibiotics and azole antifungals. They showed significant differences in metabolic profile (i.e., the fraction of drug metabolized by cytochrome P450 (CYP), CYP reaction phenotype, impact of CYP genotype on interindividual pharmacokinetics variability and CYP-mediated drug-drug interaction potential). Many events of severe adverse drug reactions and treatment failures were closely related to the ignorance of the above issues.

CONCLUSION: Clinicians should acquaint themselves with what kind of drug has less interpatient variability in clearance and whether to perform CYP genotyping prior to initiation of therapy. The relevant CYP knowledge helps clinicians to enhance the management of patients with gastrointestinal disease who may require treatment with polytherapeutic regimens.

First-line triple therapy with levofloxacin for Helicobacter pylori eradication

BACKGROUND

At present, the efficacy of proton pump inhibitor-clarithromycin-amoxicillin regimen is relatively low.

AIM

To evaluate the efficacy and tolerability of a first-line triple clarithromycin-free regimen including ranitidine bismuth citrate, levofloxacin and amoxicillin.

DESIGN

Prospective study.

PATIENTS

Helicobacter pylori-positive patients complaining of dyspeptic symptoms referred for gastroscopy.

INTERVENTION

Levofloxacin (500 mg b.d.), amoxicillin (1 g b.d.) and ranitidine bismuth citrate (400 mg b.d.) was prescribed for 10 days.

OUTCOME

Eradication was confirmed by a (13)C-urea breath test 8 weeks after therapy. Compliance with therapy was determined by questioning and the recovery of empty envelopes of medications. Incidence of adverse effects was evaluated by means of a specific questionnaire.

RESULTS

Sixty-four patients were included (30% peptic ulcer, 70% functional dyspepsia). Almost all (97%) patients took all the medications correctly. Per-protocol and intention-to-treat eradication rates were 88.5% (95% CI =78-95%) and 84.4 (74-91%). Adverse effects were reported in 9.5% of the patients, mainly including diarrhoea (7.9%); none of them were severe.

CONCLUSION

This new 10-day levofloxacin-based combination represents an alternative to clarithromycin-based therapy, as it meets the criteria set for regimens used as primary H. pylori treatment: effectiveness (>80%), simplicity (twice-daily dosing and excellent compliance) and safety (low incidence of adverse effects).

A proteomic approach for the identification of bismuth-binding proteins in Helicobacter pylori

Helicobacter pylori is a major human pathogen that can cause peptic ulcers and chronic gastritis. Bismuth-based triple or quadruple therapies are commonly recommended for the treatment of H. pylori infections. However, the molecular mechanisms underlying treatment with bismuth are currently not fully understood. We have conducted a detailed comparative proteomic analysis of H. pylori cells both before and after treatment with colloidal bismuth subcitrate (CBS). Eight proteins were found to be significantly upregulated or downregulated in the presence of CBS (20 microg mL(-1)). Bismuth-induced oxidative stress was confirmed by detecting higher levels of lipid hydroperoxide (approximately 1.8 times) and hemin (approximately 3.4 times), in whole cell extracts of bismuth-treated H. pylori cells, compared with those from untreated cells. The presence of bismuth also led to an approximately eightfold decrease in cellular protease activities. Using immobilized-bismuth affinity chromatography, we isolated and subsequently identified seven bismuth-binding proteins from H. pylori cell extracts. The intracellular levels of four of these proteins (HspA, HspB, NapA and TsaA) were influenced by the addition of CBS, which strongly suggests that they interact directly with bismuth. The other bismuth-interacting proteins identified were two enzymes (fumarase and the urease subunit UreB), and a translational factor (Ef-Tu). Our data suggest that the inhibition of proteases, modulation of cellular oxidative stress and interference with nickel homeostasis may be key processes underlying the molecular mechanism of bismuth's actions against H. pylori.

Treatment and dosing of Helicobacter pylori infection: when pharmacology meets clinic

Helicobacter pylori infection is a major cause of diseases located in the upper gastrointestinal tract. Successful eradication of the bacteria may improve H. pylori-related symptomatic complaints in functional dyspepsia, cure peptic ulcer disease and prevent gastric cancer. As vaccines are not available, the search for the optimal drug regimen has dominated the last decade. Today, most countries prefer a 7- to 10-day regimen containing a proton pump inhibitor, clarithromycin and amoxicillin as first-line treatment. An alternative (or second-line) treatment contains a proton pump inhibitor, bismuth, tetracycline and metronidazole. This review also highlights the impact of new drugs, new drug combinations, and their optimal dosing required to maximise clinical outcome.

Levofloxacin- vs. ranitidine bismuth citrate-containing therapy after H. pylori treatment failure

AIM

Ranitidine bismuth citrate and levofloxacin-based regimen may be an alternative to quadruple therapy after Helicobacter pylori eradication failure. Our aim was to compare two 7-day triple second-line regimens containing ranitidine bismuth citrate or levofloxacin.

METHODS

Patients in whom a first eradication trial with omeprazole-clarithromycin-amoxicillin had failed were randomized to receive 7-day treatment with: 1, ranitidine bismuth citrate (400 mg b.i.d.), tetracycline (500 mg q.i.d.), and metronidazole (250 mg q.i.d.), or 2, levofloxacin (500 mg b.i.d.), amoxicillin (1 g b.i.d.), and omeprazole (20 mg b.i.d.). Cure rates were evaluated by (13)C-urea breath test.

RESULTS

One-hundred patients were included: 50 received the ranitidine bismuth citrate regimen, and 50 the levofloxacin one. Groups were comparable in terms of demographic variables. Two percent of the patients (one in each group) did not return for follow up. Compliance was similar in both groups (90% took all the medications correctly). Side-effects (only mild/moderate) in the two groups were also comparable (38% with ranitidine bismuth citrate and 36% with levofloxacin). Per-protocol cure rates were 69% (95% CI = 54-80%) in the ranitidine bismuth citrate group, and 71% (57-82%) in the levofloxacin one. Intention-to-treat cure rates were, respectively, 68% (59-79%) and 68% (59-79%) (nonstatistically significant differences).

CONCLUSIONS

Both 7-day ranitidine bismuth citrate- and levofloxacin-containing second-line regimens represent alternatives to quadruple therapy in patients with previous omeprazole-clarithromycin-amoxicillin failure.

Helicobacter pylori eradication for gastric cancer prevention

Gastric cancer is the second most common fatal malignancy in the world. Its incidence is high in East Asia. Helicobacter pylori infection is an important factor in the pathogenesis of gastric cancer. Epidemiological studies have established a strong causal relationship between H. pylori infection and gastric cancer. H. pylori eradication is therefore likely to be one of the most promising approaches to gastric cancer prevention. Animal studies have shown that eradication of H. pylori infection, especially at the early stage, is effective in preventing H. pylori-related gastric carcinogenesis. However, the available data from human studies show that H. pylori eradication does not completely prevent gastric cancer and that it might be useful only in patients without atrophic gastritis or intestinal metaplasia at baseline. Longer follow-up and additional studies are needed to clarify this issue.

Third-line rescue therapy with levofloxacin is more effective than rifabutin rescue regimen after two Helicobacter pylori treatment failures

BACKGROUND

In patients with a first eradication failure, a second (rescue) therapy still fails in > 20% of cases.

AIM

To compare rifabutin and levofloxacin rescue regimens in patients with two consecutive Helicobacter pylori eradication failures.

METHODS

Patients, in whom first treatment with omeprazole-clarithromycin-amoxicillin and a second trial with omeprazole-bismuth-tetracycline-metronidazole (or ranitidine bismuth citrate with these antibiotics) had failed, received 10 days of treatment with either rifabutin (150 mg b.d.) or levofloxacin (500 mg b.d.), plus amoxicillin (1 g b.d.) and omeprazole (20 mg b.d.). Cure rates were evaluated by the (13)C-urea breath test.

RESULTS

Twenty patients received rifabutin, and 20 levofloxacin. All the patients returned for follow-up. Compliance in the rifabutin group was 100%. Four patients in the levofloxacin group did not take the medication correctly (in two cases due to adverse effects: myalgia and rash). Side effects in the rifabutin and levofloxacin groups were reported in 60% and 50% of the cases, respectively. Five patients (25%) treated with rifabutin presented with leucopenia, and six (30%) treated with levofloxacin presented with myalgias. Per-protocol cure rates were 45% (95% confidence interval, 26-66%) in the rifabutin group, and 81% (57-93%) in the levofloxacin group (P < 0.05). Intention-to-treat cure rates were, 45% (26-66%) and 85% (64-95%), respectively (P < 0.01).

CONCLUSIONS

After two previous H. pylori eradication failures, a 10-day triple levofloxacin-based rescue regimen is more effective than the same regimen with rifabutin.

Comparison of primary and secondary antimicrobial minimum inhibitory concentrations for Helicobacter pylori isolated from Korean patients

In this study we assessed minimum inhibitory concentration (MIC) values and resistance rates of several antibiotics in 65 primary and 324 secondary Helicobacter pylori isolates from Korean patients. Primary resistance to amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin and moxifloxacin was 18.5%, 13.8%, 66.2%, 12.3%, 32.3%, 33.8%, 21.5% and 21.5%, respectively. Secondary resistance was 31.3%, 85.1%, 70.1%, 0%, 89.6%, 35.8%, 32.8% and 32.8%, respectively. Sequence analysis of pbp1A in H. pylori strains with an amoxicillin MIC >or=2 microg/mL revealed C206T (Asp69-->Val), C1667G (Thr556-->Ser), A1684T (Asn562-->Tyr), A1777G (Thr593-->Ala) and C1798A (Pro600-->Thr) substitutions. Eleven (16.4%) of 67 treatment failures showed mixed infections with antibiotic-susceptible and -resistant H. pylori. The most common multidrug resistance profile was to clarithromycin, metronidazole and azithromycin. These results indicate that MIC values of secondary isolates were higher than those of primary isolates and that resistance to amoxicillin is probably mediated through mutations in pbp1A.

Third-line rescue therapy with levofloxacin after two H. pylori treatment failures

AIM

Eradication therapy with proton pump inhibitor, clarithromycin and amoxicillin fails in a considerable number of cases. A rescue therapy still fails in more than 20% of the cases. Our aim was to evaluate the efficacy and tolerability of a third-line levofloxacin-based regimen in patients with two consecutive Helicobacter pylori eradication failures.

DESIGN

Prospective multicenter study.

PATIENTS

In whom a first treatment with omeprazole-clarithromycin-amoxicillin and a second with omeprazole-bismuth-tetracycline-metronidazole (or ranitidine bismuth citrate with these antibiotics) had failed.

INTERVENTION

A third eradication regimen with levofloxacin (500 mg b.i.d.), amoxicillin (1 g b.i.d.), and omeprazole (20 mg b.i.d.) was prescribed for 10 days.

OUTCOME

Eradication was confirmed with 13C-urea breath test 4-8 wk after therapy.

RESULTS

One-hundred patients were initially included, and nine were lost for follow-up. All patients but five took all the medications correctly. Per-protocol and intention-to-treat eradication rates were 66% (95% CI = 56-75%) and 60% (50-70%). Adverse effects were reported in 25% of the patients, mainly including metallic taste (8%), nausea (8%), myalgia/arthralgia (5%), and diarrhea (4%); none of them were severe.

CONCLUSION

Levofloxacin-based rescue therapy constitutes an encouraging empirical third-line strategy after multiple previous H. pylori eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, and tetracycline.

Systematic review and meta-analysis: levofloxacin-based rescue regimens after Helicobacter pylori treatment failure

BACKGROUND

A quadruple therapy has been generally recommended as rescue regimen for Helicobacter pylori eradication failures.

AIMS

To systematically review the efficacy and tolerance of levofloxacin-based rescue regimens, and to conduct a meta-analysis of studies comparing these regimens with quadruple therapy for H. pylori eradication failures.

METHODS

Selection of studies -- levofloxacin-based rescue regimens. For the meta-analysis, randomized-controlled trials comparing levofloxacin-based and quadruple regimens. Search strategy -- electronic and manual. Assessment of study quality -- independently by two reviewers. Data synthesis --'intention-to-treat' eradication rate.

RESULTS

Mean eradication rate with levofloxacin-based regimens was 80%. Ten-day regimens were more effective than 7-day combinations (81% vs. 73%; P < 0.01). The meta-analysis showed better results with levofloxacin than with the quadruple combination (81% vs. 70%; OR = 1.80; 95% CI = 0.94-3.46). This difference reached statistical significance and heterogeneity markedly decreased when a single outlier study was excluded or when only high-quality studies were considered. Meta-analysis showed less adverse effects with levofloxacin than with quadruple regimen, both overall (19% vs. 44%; OR = 0.27; 95% CI = 0.16-0.46) and regarding severe adverse effects (0.8% vs. 8.4%; OR = 0.20; 95% CI =0.06-0.67).

CONCLUSIONS

After H. pylori eradication failure, levofloxacin-based rescue regimen is more effective and better tolerated than the generally recommended quadruple therapy. A 10-day combination of levofloxacin-amoxicillin-proton pump inhibitor constitutes an encouraging second-line alternative.

Helicobacter pylori first-line treatment and rescue options in patients allergic to penicillin

BACKGROUND

Helicobacter pylori eradication is a challenge in patients allergic to penicillin, especially those who have failed a first-eradication trial.

AIM

To assess the efficacy and tolerability of H. pylori first-line treatment and rescue options in patients allergic to penicillin.

METHODS

Prospective single centre study including 40 consecutive treatments administered to patients allergic to penicillin. Therapy regimens: First-line (12 patients) omeprazole, clarithromycin and metronidazole for 7 days; second-line (17 patients) ranitidine bismuth citrate, tetracycline and metronidazole for 7 days; third-line (nine patients) rifabutin, clarithromycin and omeprazole for 10 days; and fourth-line (two patients) levofloxacin, clarithromycin and omeprazole for 10 days.

OUTCOME VARIABLE

a negative (13)C-urea breath test 8 weeks after completion of treatment.

RESULTS

Per-protocol/intention-to-treat eradication rates were: first-line (64/58%); second-line (ranitidine bismuth citrate; 53/47%); third-line (rifabutin; 17/11%) and fourth-line regimen (levofloxacin; 100/100%). Compliance with treatment was generally good, except with the rifabutin-based regimen, which presented adverse effects in 89% of the patients, including four cases of myelotoxicity.

CONCLUSIONS

H. pylori-infected patients who are allergic to penicillin may be treated with a first-line treatment combining a proton-pump inhibitor, clarithromycin and metronidazole. Rescue options may include a regimen with ranitidine bismuth citrate, tetracycline and metronidazole. A levofloxacin-based rescue regimen (with proton-pump inhibitor and clarithromycin) may also represent an alternative, even when two or more consecutive eradication treatments have previously failed. However, rifabutin + clarithromycin + proton-pump inhibitor regimen is ineffective and poorly tolerated.

Helicobacter pylori "rescue" therapy after failure of two eradication treatments

Nowadays, apart from having to know well first-line eradication regimens, we must also be prepared to face Helicobacter pylori treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final--overall--eradication rate. After failure of a combination of proton pump inhibitor (PPI), amoxicillin, and clarithromycin, the use of empirical quadruple therapy (PPI-bismuth-tetracycline-metronidazole), has been generally used as the optimal second-line therapy. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several "rescue" therapies are consecutively given. It seems that performing culture even after a second eradication failure may not be necessary, as it is possible to construct an overall strategy to maximize H. pylori eradication, based on the different possibilities of empirical treatment (when antibiotic susceptibilities are unknown). Thus, if one does not want to perform culture before the administration of the third treatment after failure of the first two, different empirical treatments exist, including regimens based on: 1, amoxicillin (amoxicillin-PPI at high doses); 2, amoxicillin plus tetracycline (PPI-bismuth-tetracycline-amoxicillin, or ranitidine-bismuth-citrate-tetracyline-amoxicillin); 3, rifabutin (rifabutin-amoxicillin-PPI); 4, levofloxacin (levofloxacin-amoxicillin-PPI); and 5, furazolidone (furazolidone-bismuth-tetracycline-PPI).

Trends in the prevalence of peptic ulcer disease and Helicobacter pylori infection in family physician-referred uninvestigated dyspeptic patients in Hong Kong

BACKGROUND

Peptic ulcer disease is mainly caused by Helicobacter pylori infection and the use of non-steroidal anti-inflammatory drugs.

AIM

To investigate the trends in the prevalence of peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use in uninvestigated dyspeptic patients over recent years in Hong Kong.

METHODS

Data from consecutive patients with uninvestigated dyspeptic symptoms referred by family physicians for open access upper endoscopy during 1997 and 2003 were analysed in relation to peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use.

RESULTS

Among 2700 patients included, 405 (15%) had peptic ulcer disease and 14 (0.5%) had gastric cancer. There was a reduced trend from 1997 to 2003 in the prevalence of peptic ulcer disease (17, 20, 14, 16, 13, 14 and 14%, respectively, chi2 = 5.80, P = 0.016) (mainly because of decrease in duodenal ulcers), H. pylori infection (44, 50, 49, 44, 40, 40, 36 and 43%, respectively, chi2 = 13.55, P < 0.001) and non-steroidal anti-inflammatory drug use (13, 5, 5, 6, 3, 4, 4 and 5% respectively, chi2 = 13.61, P < 0.001). The prevalence of peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use between 2001 and 2003 were significantly lower than that between 1997 and 2000 (17% vs. 13%, OR = 0.78, 95% CI: 0.63-0.96, P = 0.020 for peptic ulcer disease; 47% vs. 39%, OR =0.72, 95% CI: 0.60-0.86, P < 0.001 for H. pylori infection; and 6% vs. 4%, OR = 0.56, 95% CI: 0.39-0.82, P = 0.002 for non-steroidal anti-inflammatory drug use). H. pylori infection was associated with both duodenal ulcer (OR = 15.87, 95% CI: 10.60-23.76, P < 0.001) and gastric ulcer (OR = 3.12, 95% CI: 2.15-4.53, P < 0.001) whereas non-steroidal anti-inflammatory drug use was only associated with gastric ulcer (OR = 2.97, 95% CI: 1.70-5.20, P < 0.001).

CONCLUSIONS

The prevalence of peptic ulcer disease, mainly duodenal ulcers, was reduced in association with a decreasing trend in the prevalence of H. pylori infection and non-steroidal anti-inflammatory drug use from 1997 to 2003.

Distribution of antibiotic MICs for Helicobacter pylori strains over a 16-year period in patients from Seoul, South Korea

Recently, the development of antibiotic resistance emerged as a significant clinical problem in the eradication of Helicobacter pylori. We investigated the MICs of antibiotics for 135 H. pylori isolates from adults in Seoul, South Korea, over the past 16 years. The MICs of amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, and ciprofloxacin increased from 1987 to 2003. Rates of primary resistance to clarithromycin increased from 2.8% in 1994 to 13.8% in 2003. The A2144G mutation was frequently observed in the 23S rRNA gene in clarithromycin-resistant isolates. The increase in resistance to clarithromycin seems to result in a decrease in eradication efficacy for H. pylori. These results suggest that the MICs of several antibiotics for H. pylori have increased over the past 16 years in Seoul.

Photodynamic therapy targeted to pathogens

Photodynamic therapy (PDT) employs a non-toxic dye termed a photosensitizer (PS) together with low intensity visible light, which, in the presence of oxygen, produce cytotoxic species. PS can be targeted to its destination cell or tissue and, in addition, the irradiation can be spatially confined to the lesion giving PDT the advantage of dual selectivity. This promising approach can be used for various applications including microbial inactivation and the treatment of infections. Resistance to PDT has not been shown and multiantibiotic-resistant strains are as easily killed as naive strains. It is known that Gram (+) bacteria are more sensitive to PDT as compared to Gram (-) species. However, the use of cationic PS or agents that increase the permeability of the outer membrane allows for the effective killing of Gram (-) organisms. Some PS have an innate positive charge, but our approach is to link PS to a cationic molecular vehicle such as poly-L-lysine. This modification dramatically increases PS binding to and penetrating through the negatively charged bacterial permeability barrier. Due to focused light delivery the use of PDT is possible only for localized infections. Nonetheless numerous diseases can be treated. Selectivity of the PS for microbes over host cells, accurate delivery of the PS into the infected area, and PDT dose adjustment help minimize side effects and give PDT an advantage over conventional therapy. There are only a few reports about the use of antimicrobial PDT in animal models and clinical trials. We have used genetically modified bioluminescent bacteria to follow the effect of PDT in infected wounds, burns, and soft tissue infections in mice. Not only were bacteria infecting wounds, burns, and abscesses killed, but mice were saved from death due to sepsis and wound healing was improved.

Basis for the management of drug-resistant Helicobacter pylori infection

The discovery that most stomach diseases are a consequence of an Helicobacter pylori infection has completely changed the management of stomach diseases. Antibacterials are the treatment of choice in addition to proton pump inhibitors (PPIs) or ranitidine bismuth. We are now faced with the problem of antimicrobial resistance, which is the main cause of treatment failure. H. pylori acquires resistance essentially via point mutations, and today this phenomenon is found with most antibacterials. The most important resistance to consider is that to clarithromycin, since it is the first-choice antibacterial and clarithromycin resistance is highly clinically significant. Quadruple therapy or triple therapies with amoxicillin-metronidazole or tetracycline-metronidazole and a PPI or ranitidine bismuth can then be used despite a possible resistance to metronidazole if the strain is resistant to clarithromycin. Resistance to both clarithromycin and metronidazole may lead to the use of other combinations, i.e. amoxicillin-rifabutin, amoxicillin-levofloxacin or amoxicillin-furazolidone. Resistance to any of these drugs means their use must be avoided. In some instances, it may also be advisable to prescribe amoxicillin as the sole antibacterial, or to use a quadruple therapy with furazolidone instead of metronidazole. Although it is theoretically possible to cure a drug-resistant H. pylori infection, a practical limitation is the availability of the drugs in certain countries. Furthermore, the progressive increase in drug resistance warrants the need for new antibacterials in the near future.

[Evaluation of Helicobacter pylori susceptibility to rifaximin]

INTRODUCTION

Helicobacter pylori infection affects more than half the world's population. It is a major cause of chronic gastritis and there is a strong association with peptic ulceration and gastric adenocarcinoma. Rifaximin is a new nonabsorbable broad-spectrum antimicrobial agent that reaches high concentrations in the gastrointestinal tract.

AIM

To evaluate the in vitro activity of rifaximin against H. pylori isolates.

METHODS

Thirty-one H. pylori strains were analyzed by the agar dilution method. Clarithromycin was used as the control antibiotic. Staphylococcus aureus and Streptococcus pneumoniae were used as quality control strains. Plates were read at days 4 and 7 of incubation. The MIC50 and MIC90 of each antibiotic were calculated. Strains with a clarithromycin MIC of > 1 microg/ml were considered resistant.

RESULTS

The MIC50 of clarithromycin at days 4 and 7 was 0.125 microg/ml and the MIC90 at days 4 and 7 ranged from 8 to 16 microg/ml, respectively. The MIC50 of rifaximin at days 4 and 7 ranged from 1 to 2 microg/ml, respectively, and the MIC90 was 4 microg/ml at both days 4 and 7. Twenty percent of H. pylori strains were resistant to clarithromycin. All clarithromycin-resistant strains were inhibited at a maximal rifaximin concentration of 4 microg/ml.

CONCLUSION

These results indicate that this new antibiotic may be useful for eradication of H. pylori infection. Because rifaximin is active against H. pylori strains resistant to clarithromycin, it could be useful in combination with this drug or in the treatment of therapeutic failure.

Rapid detection of point mutations in the gyrA gene of Helicobacter pylori conferring resistance to ciprofloxacin by a fluorescence resonance energy transfer-based real-time PCR approach

As a result of the increasing resistance of Helicobacter pylori against first-line antibiotics, other drugs, such as quinolones, will be needed for eradication therapy in the future. We developed a real-time PCR to detect mutations in the gyrA gene associated with ciprofloxacin resistance of H. pylori, thereby contributing to the selection of patients who could be treated by ciprofloxacin-based therapy.

[Eradication and chronic acid suppression. Advances and pseudo-advances]

Guidelines for Helicobacter pylori therapy were proposed at the Maastricht 2/2000 conference. Since then no further major developments have been made. An evidenced based choice of treatment is thereby nearly impossible as large randomized trials have not been performed. Minor progress could be achieved in the areas of second-line and rescue treatment options after failure of the standard therapy. At present proton pump inhibitors are the most powerful drugs for the treatment of gastro-oesophageal reflux disease. No additional progress has been achieved concerning therapy of reflux disease in the last years. Reasonable anxiety about the safety of long-term acid suppression with proton pump inhibitors diminished over years as no significant increase in cancer development could be detected.

Photodynamic therapy: a new antimicrobial approach to infectious disease?

Photodynamic therapy (PDT) employs a non-toxic dye, termed a photosensitizer (PS), and low intensity visible light which, in the presence of oxygen, combine to produce cytotoxic species. PDT has the advantage of dual selectivity, in that the PS can be targeted to its destination cell or tissue and, in addition, the illumination can be spatially directed to the lesion. PDT has previously been used to kill pathogenic microorganisms in vitro, but its use to treat infections in animal models or patients has not, as yet, been much developed. It is known that Gram-(-) bacteria are resistant to PDT with many commonly used PS that will readily lead to phototoxicity in Gram-(+) species, and that PS bearing a cationic charge or the use of agents that increase the permeability of the outer membrane will increase the efficacy of killing Gram-(-) organisms. All the available evidence suggests that multi-antibiotic resistant strains are as easily killed by PDT as naive strains, and that bacteria will not readily develop resistance to PDT. Treatment of localized infections with PDT requires selectivity of the PS for microbes over host cells, delivery of the PS into the infected area and the ability to effectively illuminate the lesion. Recently, there have been reports of PDT used to treat infections in selected animal models and some clinical trials: mainly for viral lesions, but also for acne, gastric infection by Helicobacter pylori and brain abcesses. Possible future clinical applications include infections in wounds and burns, rapidly spreading and intractable soft-tissue infections and abscesses, infections in body cavities such as the mouth, ear, nasal sinus, bladder and stomach, and surface infections of the cornea and skin.