Emerging therapies for the treatment of Helicobacter pylori infections

Multicenter Evaluation of a Gradient Diffusion Method for Antimicrobial Susceptibility Testing of Helicobacter pylori

Helicobacter pylori is an important human pathogen associated with peptic ulcer disease, dyspepsia, and gastric malignancy. Antimicrobial susceptibility testing (AST) is often requested for patients who fail eradication therapy. The Clinical and Laboratory Standards Institute (CLSI) reference method, agar dilution (AD), is not performed in most laboratories and maintaining organism viability during transit to a reference laboratory is difficult. We assessed the performance of the Etest (bioMérieux) as a method for H. pylori AST in comparison to AD. Etest MICs were determined for 83 H. pylori isolates at ARUP and Cleveland Clinic (CC). Categorical agreement (CA), very major, major, and minor errors (VME, ME, and mE) were determined for Etest using AD performed at Mayo Clinic Laboratories as the reference method. Testing on isolates with errors was repeated to determine final results summarized below. For clarithromycin, 66.3% of isolates were resistant (R) by AD; Etest results at each laboratory showed 1mE (1.2%) and 1 ME (3.8%). For tetracycline, only 2 isolates were R by AD; a single VME occurred at both sites (98.8% CA, 50% VME) with the same isolate. Applying EUCAST levofloxacin breakpoints to interpret ciprofloxacin results, 60.2% of isolates were R by AD; ARUP CA was 97.6% (1 ME (3%), 1 VME (2%)) and CC CA was 96.3% (1 ME (3%), 2 VMEs (4%)). Despite high error rates, the categorical agreement was acceptable (>90%) for all three antibiotics between AD and Etest. In-house susceptibility testing by gradient diffusion can allow for testing of fastidious organisms that may not survive transport to specialized laboratories; however, the method is not without technical challenges. Characterization of resistance mechanisms, increased AD dilutions, and testing from the same inoculum may determine if the observed errors reflect technical issues or breakpoints that need optimization.

IMPORTANCE Routine antimicrobial susceptibility testing (AST) of Helicobacter pylori by agar dilution is difficult to perform and not practical in most clinical microbiology laboratories. The Etest gradient diffusion method can be a reliable alternative for H. pylori AST with the advantage of being a less laborious quantitative method. This work reveals that an optimized Etest method can provide acceptable performance for H. pylori AST and describes the challenges associated with this methodology.

Time latencies of Helicobacter pylori eradication after peptic ulcer and risk of recurrent ulcer, ulcer adverse events, and gastric cancer: a population-based cohort study

BACKGROUND AND AIMS

Helicobacter pylori is associated with peptic ulcer disease and gastric cancer. Therefore we wanted to test how various lengths of delays in H pylori eradication therapy influence the risk of recurrent peptic ulcer, ulcer adverse events, and gastric cancer.

METHODS

This population-based nationwide Swedish cohort study included 29,032 patients receiving H pylori eradication therapy after peptic ulcer disease in 2005 to 2013. Predefined time intervals between date of peptic ulcer diagnosis and date of eradication therapy were analyzed in relation to study outcomes. Cox regression provided hazard ratios (HRs) and 95% confidence intervals (95% CIs), adjusted for age, sex, comorbidity, history of ulcer disease, use of ulcerogenic drugs, and use of proton pump inhibitors (PPIs).

RESULTS

Compared with eradication therapy within 7 days of peptic ulcer diagnosis, eradication therapy within 8 to 30, 31 to 60, 61 to 365, and >365 days corresponded with HRs of recurrent ulcer of 1.17 (95% CI, 1.08-1.25), 2.37 (95% CI, 2.16-2.59), 2.96 (95% CI, 2.76-3.16), and 3.55 (95% CI, 3.33-3.79), respectively. The corresponding HRs for complicated ulcer were 1.55 (95% CI, 1.35-1.78), 3.19 (95% CI, 2.69-3.78), 4.00 (95% CI, 3.51-4.55), and 6.14, (95% CI, 5.47-6.89), respectively. For gastric cancer the corresponding HRs were .85 (95% CI, .32-2.23), 1.31 (95% CI, .31-5.54), 3.64 (95% CI, 1.55-8.56), and 4.71 (95% CI, 2.36-9.38), respectively.

CONCLUSIONS

Delays in H pylori eradication therapy after peptic ulcer diagnosis time-dependently increase the risk of recurrent ulcer, even more so for complicated ulcer, starting from delays of 8 to 30 days.

Comparison of three different regimens against Helicobacter pylori as a first-line treatment: A randomized clinical trial

Treatments with bismuth-containing quadruple therapy (QT), sequential therapy (ST), or concomitant therapy (CT) have been proposed as empirical first-line regimens for Helicobacter pylori. We compared the efficacy and tolerability of 10 days bismuth-containing quadruple QT, 10 days ST, and 10 days CT with as first-line treatments for H. pylori in a randomized crossover study. The subjects were randomly divided into three groups. The first 130 patients were treated with rabeprazole, bismuth potassium citrate, metronidazole, and tetracycline for 10 days. The second 130 patients in the sequential group were treated with rabeprazole and amoxicillin for 5 days, and then rabeprazole, clarithromycin, and metronidazole for an additional 5 days. The last 130 patients in the concomitant group were treated with rabeprazole, amoxicillin, clarithromycin, and metronidazole for 10 days. H. pylori eradication was confirmed by urea breath test at 6 weeks. The primary outcome was eradication rates of first-line treatment by intention to treat and per protocol (PP) analyzes. There was no difference between the average ages and the male/female ratio of the groups. The PP analysis was performed on 121, 119, and 118 patients in the QT, ST, and CT groups, respectively. In the PP analysis, the successful eradication 94.2% (114/121), 95.0% (113/119), and 95.8% (113/118) the QT, ST, and CT groups, respectively. There was no significant difference among the three groups (p = 0.86). 10 days QT, ST, and CT are highly effective as empirical first-line therapies for H. pylori in the region with high clarithromycin resistance.

Pharmacological therapy used in the elimination of Helicobacter pylori infection: A review

The optimal therapy for Helicobacter pylori (H. pylori) infection should combine a high cure rate and a short treatment duration with a favorable side-effect profile and should maintain a low cost. Several strategies have been proposed to increase the H. pylori eradication rate, including the extension of the treatment duration to 14 d, the use of a four-drug regimen (quadruple, sequential, and concomitant treatments), and the use of novel antibiotics, such as levofloxacin. However, triple therapy remains the most widely accepted first-line treatment regimen in Brazil and the United States and throughout Europe. Because this therapy is limited by resistance to clarithromycin, other therapeutic regimens have been investigated worldwide. This review describes the current literature involving studies directly comparing these different therapies and their efficacies.

Efficacy of a "Rescue" Ciprofloxacin-Based Regimen for Eradication of Helicobacter pylori Infection after Treatment Failures

The aim of our study was to evaluate the efficacy and tolerability of a ciprofloxacin-based regimen for H. pylori eradication failures as an alternative to bismuth based quadruple therapy. Methods. Design: prospective single-center study. Patients in whom a first eradication trial with omeprazole/esomeprazole, clarithromycin plus amoxicillin or tinidazole/metronidazole had failed were included. H. pylori status: established by histology, rapide urease test and polymerase chain reaction. Intervention: esomeprazole 20 mg, ciprofloxacin 500 mg, and metronidazole 500 mg, administered together before breakfast and dinner for 10 days. Susceptibility testing was performed by the Epsilometer test. Ciprofloxacin resistance was defined as a MIC of ≥1 μg/mL. Eradication was established by a negative 13C-UBT and 4–6 weeks post-therapy. Efficacy and side effects were determined. Results. 34 patients were enrolled, 32 completed the study. Compliance was excellent (100%). Side effects were mild. Ciprofloxacin-based therapy cured 65% (22/34) of patients by intention to treat and 69% (22/32) per protocol analysis. The prevalence of ciprofloxacin resistance was 8%. Conclusions. The effectiveness of ciprofloxacin-based therapy was greatly reduced despite the high prevalence of ciprofloxacin sensitive H. pylori strains. Bismuth based quadruple therapy still remain the best choice as a “rescue” regimen in our region.

Review article: rifabutin in the treatment of refractory Helicobacter pylori infection

BACKGROUND

Even with the current most effective treatment regimens, a relevant proportion of patients will fail to eradicate Helicobacter pylori infection.

AIM

To evaluate the role of rifabutin in the treatment of H. pylori infection.

METHODS

Bibliographical searches were performed in MEDLINE. Data on the efficacy of rifabutin-containing regimens on H. pylori eradication were combined and meta-analysed using the generic inverse variance method.

RESULTS

Rifabutin shows good in vitro activity against H. pylori. Mean H. pylori rifabutin resistance rate (calculated from 11 studies including 2982 patients) was 1.3% (95% confidence interval = 0.9-1.7%). When only studies including patients naïve to H. pylori eradication treatment were considered, this figure was even lower (0.6%). On the other hand, higher values of rifabutin resistance were calculated (1.59%) when only post-treatment patients were considered. Overall, mean H. pylori eradication rate (intention-to-treat analysis) with rifabutin-containing regimens (1008 patients) was 73% (67-79%). Respective cure rates for second-line (223 patients), third-line (342 patients) and fourth/fifth-line (95 patients) rifabutin therapies were 79% (67-92%), 66% (55-77%) and 70% (60-79%) respectively. For treating H. pylori infection, almost all studies have administered rifabutin 300 mg/day; this dose seems to be more effective than 150 mg/day. The ideal length of treatment remains unclear, but 10- to 12-day regimens are generally recommended. The mean rate of adverse effects was 22% (19-25%). Myelotoxicity is the most significant, although this complication was rare. Until now, all patients have recovered of leucopenia uneventfully in a few days, and there have been no reports of infection or other adverse outcomes related to it.

CONCLUSION

Rifabutin-containing rescue therapy constitutes an encouraging strategy after multiple (usually three) previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline and levofloxacin.

Anti-Helicobacter pylori activity of fermented milk with lactic acid bacteria

BACKGROUND

Ten strains of lactic acid bacteria (LAB) were investigated for their anti-Helicobacter pylori effects. The bactericidal activity and organic acid content in spent culture supernatants (SCS) from fermented milk were measured. In addition, the exclusion effect of SCS against H. pylori infection of human gastric epithelial AGS cells was assayed.

RESULTS

Three LAB strains, LY1, LY5 and IF22, showed better anti-Helicobacter effects than the other strains. There were no significant differences in the bactericidal activity of LAB strains between original SCS, artificial SCS and SCS treated by heating or protease digestion. However, neutralised SCS lost this activity. These results suggest that the anti-H. pylori activity of SCS may be related to the concentration of organic acids and the pH value but not to protein components. In the AGS cell culture test, both fermented LY5-SCS and artificial LY5-SCS significantly reduced H. pylori infection and urease activity (P < 0.05).

CONCLUSION

In this study, in vitro methods were used to screen potential probiotics with anti-H. pylori activity. This may provide an excellent and rapid system for studying probiotics in the functional food and dairy industries.

Photodynamic therapy for localized infections--state of the art

Photodynamic therapy (PDT) was discovered over 100 years ago by observing the killing of microorganisms when harmless dyes and visible light were combined in vitro. Since then it has primarily been developed as a treatment for cancer, ophthalmologic disorders and in dermatology. However, in recent years interest in the antimicrobial effects of PDT has revived and it has been proposed as a therapy for a large variety of localized infections. This revival of interest has largely been driven by the inexorable increase in drug resistance among many classes of pathogen. Advantages of PDT include equal killing effectiveness regardless of antibiotic resistance, and a lack of induction of PDT resistance. Disadvantages include the cessation of the antimicrobial effect when the light is turned off, and less than perfect selectivity for microbial cells over host tissue. This review will cover the use of PDT to kill or inactivate pathogens in ex vivo tissues and in biological materials such as blood. PDT has been successfully used to kill pathogens and even to save life in several animal models of localized infections such as surface wounds, burns, oral sites, abscesses and the middle ear. A large number of clinical studies of PDT for viral papillomatosis lesions and for acne refer to its antimicrobial effect, but it is unclear how important this microbial killing is to the overall therapeutic outcome. PDT for periodontitis is a rapidly growing clinical application and other dental applications are under investigation. PDT is being clinically studied for other dermatological infections such as leishmaniasis and mycobacteria. Antimicrobial PDT will become more important in the future as antibiotic resistance is only expected to continue to increase.

Guidelines for the treatment of bacterial vaginosis: focus on tinidazole

Bacterial vaginosis (BV) is a complex vaginal infection most commonly associated with women of child-bearing age. Risk factors for BV are numerous. There are currently multiple clinical and laboratory tests for diagnosis of BV, including the most commonly used diagnostic methods: Amsel’s criteria or Nugent’s Gram stain scale. The mainstay of BV therapy is metronidazole, but tinidazole as well as a few other agents have also been used successfully. Tinidazole is the second nitroimidazole antiprotozoal agent and a structural derivative of metronidazole. With a favorable pharmacokinetic profile and reduced side effects, tinidazole is an alternative agent for BV treatment. There are minimal head-to-head comparative data to establish tinidazole’s superiority to metronidazole or other therapeutic agents. Available data suggest tinidazole has a role in special populations particularly for refractory or relapsing BV.

Refractory peptic ulcer disease

Refractory PUD is a diagnostic and therapeutic challenge. Optimal management of severe or refractory PUD requires a multidisciplinary team approach, using primary care providers, gastroenterologists, and general surgeons. Medical management has become the cornerstone of therapy. Identification and eradication of H pylori infection combined with acid reduction regimens can heal ulceration and also prevent recurrence. Severe, intractable or recurrent PUD and associated complications mandates a careful and methodical evaluation and management strategy to determine the potential etiologies and necessary treatment (medical or surgical) required.