Nitrofurantoin quadruple therapy for Helicobacter pylori infection: effect of metronidazole resistance

Newer, Older, and Alternative Agents for the Eradication of Helicobacter pylori Infection: A Narrative Review

Although discovered 40 years ago, Helicobacter pylori infection is still raising diagnostic and therapeutic problems today. The infection is currently managed based on statements in several guidelines, but implementing them in practice is a long process. Increasing antibiotic resistance and weak compliance of the patients limit the efficacy of eradication regimens, leaving much room for improvement. Third-generation proton pump inhibitors have added little to the results of the first two generations. Potassium-competitive acid blockers have a stronger and longer inhibitory action of acid secretion, increasing the intragastric pH. They obtained superior results in eradication when compared to proton pump inhibitors. Instead of innovative antibiotics, derivatives of existing antimicrobials were developed; some new fluoroquinolones and nitazoxanide seem promising in practice, but they are not recommended by the guidelines. Carbonic anhydrase inhibitors have both anti-secretory and bactericidal effects, and some researchers are expecting their revival in the treatment of infection. Capsules containing components of the eradication regimens have obtained excellent results, but are of limited availability. Probiotics, if containing bacteria with anti-Helicobacter pylori activity, may be useful, increasing the rates of eradication and lowering the prevalence and severity of the side effects.

Clarithromycin-, and metronidazole-resistant Helicobacter pylori isolated from raw and ready-to-eat meat in Mansoura, Egypt

Helicobacter pylori (H. pylori), classified as a class-I carcinogen, is one of the leading medical pathogens of global concern associated mainly with the development of gastric adenocarcinomas and gastric mucosa-associated lymphoid tissue lymphomas; nevertheless, its prevalence in food especially meat and meat products is not fully covered. Additionally, the resistance of H. pylori towards clarithromycin is increasing worldwide and consider the leading cause of H. pylori treatment failure. Thus, the present study was designed to determine the prevalence, molecular characterization, and antimicrobial resistance profiles of clarithromycin-, and metronidazole-resistant H. pylori isolated from raw and ready-to-eat meat samples retailed in Mansoura city, Egypt. Among the 250 samples tested, H. pylori were molecularly confirmed in 40.8 % (49/120) of raw meat products and in 29.2 % (38/130) of ready-to-eat meat products. Precisely, 53.3 % (32/60), 56.7 % (17/30), 40 % (8/20), 55 % (11/20), 60 % (12/20), 13.3 % (4/30), and 15 % (3/20) of raw ground beef, beef burger, beef burger sandwiches, beef shawarma sandwiches, beef kofta sandwiches, beef luncheon, and beef sausage sandwiches, respectively were positive for H. pylori. Of the 204 biochemically-identified H. pylori isolates, 53.9 % (110/204) were molecularly confirmed by PCR through the detection of glmM, cagA, or vacA genes, which were detected at an incidence of 95.5 % (105/110), 77.3 % (85/110), and 20.9 % (23/110) among the isolates, respectively. The antimicrobial sensitivity testing revealed that all of the 110 (100 %) molecularly-confirmed H. pylori isolates were multidrug-resistant (MDR; resistant to four or more antibiotics). Interestingly, 100 % and 61.8 % of H. pylori isolated from raw and ready-to-eat meat were resistant to metronidazole and clarithromycin, respectively which consider alarming results as metronidazole and clarithromycin are the mainstay antibiotics in the treatment of H. pylori infections. Additionally, 94.5 %, 94.5 %, 24.5 %, 23.6 %, and 13.6 % of isolates were resistant to vancomycin, sulphamethoxazole-trimethoprim, imipenem, levofloxacin, and nitrofurantoin, respectively. The widespread contamination of examined raw and ready-to-eat meat product samples with MDR H. pylori isolates could constitute a tremendous public health hazard. Further studies concerning the prevalence and possible methods of elimination of H. pylori in different food categories distributed in the various provinces in Egypt as well as in other countries is required for a better understanding the H. pylori as an emerging foodborne pathogen.

Second-line and third-line trial for helicobacter pylori infection in patients with duodenal ulcers: A prospective, crossover, controlled study

BACKGROUND

Following standard first-line triple therapies for Helicobacter pylori infection, up to 20% of patients require further eradication.

OBJECTIVE

The aim of this study was to assess the effects of second-line triple therapies and third-line quadruple therapies for the eradication of H pylori.

METHODS

This 7-week, prospective, crossover, controlled, second- and third-line trial was conducted at the Department of Gastroenterology, Ferencváros Health Center (Budapest, Hungary). Patients aged 18 to 80 years with duodenal ulcers and an H pylori infection resistant to first-line triple therapy (pantoprazole 40 mg BID + amoxicillin 1000 mg BID + clarithromycin 500 mg BID [PAC] given as tablets) received a different triple therapy regimen (ranitidine bismuth citrate 400 mg BID + metronidazole 500 mg BID + clarithromycin 500 mg BID [RBC-MC]) for 7 days (group 1A), and nonresponders after RBC + 2 antimicrobials received the pantoprazole-based regimen (group 1B). After secondary failure, patients were randomized to receive quadruple therapies: pantoprazole, amoxicillin, tetracycline, and either nitrofurantoin or bismuth subsalicylate (groups 2A and 2B).

RESULTS

One hundred thirty-four patients were enrolled in the second-line study (56 men, 78 women; mean [SD] age, 51.1 [12.4] years; group 1A, 68 patients; group 1B, 66 patients). Subsequently, 41 (30.6%) of these patients were randomized to receive quadruple therapies. Using intent-to-treat (ITT) analysis, the eradication rates did not differ significantly (60.3% and 65.2% in groups 1A and 1B, respectively; 61.9% and 55.0% in groups 2A and 2B, respectively). Perprotocol eradication rates did not differ significantly (66.1% and 68.3% in groups 1A and 1B, respectively); however, the rates were significantly different in group 2A (66.7%) versus group 2B (55.5%) (P = 0.03).

Nitrofuran-based regimens for the eradication of Helicobacter pylori infection

Several aspects of Helicobacter pylori eradication have been meta-analyzed; however, nitrofuran-based therapies constitute an exception. The aim of this study was the systematic review and meta-analysis of the effect of furazolidone- and nitrofurantoin-based regimens in the eradication of infection. Studies evaluating the effects of nitrofurans on H. pylori were identified from Medline, EMBASE, the Cochrane Controlled Trials Register and congress abstracts. The studies were classified into groups based on first-, second- and third-line regimens. The pooled eradication rates and combined odd ratios of the individual studies were calculated and compared with the published meta-analysis. The factors influencing the efficiency of the regimens were also analyzed. Side-effects of nitrofuran-based regimens were also analyzed. The pooled eradication rate of primary proton pump inhibitor-based regimens containing furazolidone was 76.3% (CI 67.8-84.2). The odds ratio for furazolidone-based regimens versus standard triple therapies was 2.34 (CI 0.76-3.92). Ranitidine bismuth citrate + furazolidone-based triple regimens were equally efficient (83.5%, CI 74.0-93.0, P = 0.06 versus triple therapies). Schedules including a H(2) antagonist + furazolidone + one other antibiotic achieved pooled eradication rates of 79.9% (CI 67.8-89.9, P = 0.04). Bismuth-based triple therapies achieved 84.5% (CI 72.6-93.0, P = 0.002). Primary quadruple regimens containing furazolidone were superior to triple therapies (83.4%, CI 69.7-92.3, P = 0.01). Second-line schedules containing furazolidone obtained eradication rates of 76.1% (CI 66.4-85.0, P = 0.28 versus primary regimens). Third-line 'rescue' therapies were efficient in 65.5% of the cases (CI 56.3-75.5, P = 0.0001). Side-effects of the regimens containing furazolidone were more frequent than in standard therapies (P = 0.02). The combined odds ratio of side-effects for furazolidone-based versus standard therapies was 0.74 (CI 0.32-1.98). The duration of treatment, but not the furazolidone dose, influenced the treatment outcome. Primary triple regimens containing furazolidone are slightly less efficient than the standard primary combinations; primary quadruple regimens were more efficient than triple therapies. Furazolidone is also efficient as a component of second-line or rescue therapies.

Alternative and rescue treatment regimens for Helicobacter pylori eradication

Eradication therapy has been incorporated into clinical practice. The regimens currently recommended for first-line treatment include a 2-week bismuth-based triple therapy (mainly in developing countries), a 1 - 2 week proton pump inhibitor (PPI)-based triple therapy and a 1-week ranitidine bismuth citrate (RBC)-based triple therapy. However, these regimens fail to eradicate Helicobacter pylori in up to 20% of patients due to poor compliance, inadequate treatment duration, smoking, old age and bacterial resistance to nitroimidazoles and/or macrolides in particular. Therefore, alternative regimens that avoid nitroimidazoles and/or macrolides or overcome bacterial resistance to these drugs, improve compliance, minimise side effects and/or reduce costs have been evaluated. One-week quadruple therapy, which adds a PPI or histamine receptor 2-blocker to bismuth-based triple therapy, usually achieves an eradication rate of 90% when used as an alternative first-line therapy but the efficacy decreases when used as a rescue therapy. Several new triple therapies that may be used as alternative and/or rescue therapies have been evaluated. Among these are furazolidone-based (furazolidone plus an antibiotic and a bismuth salt, a PPI or RBC), fluoroquinolone-based (levofloxacin or moxifloxacin plus an antibiotic and a PPI) and ecabet sodium-based (ecabet plus two antibiotics) triple therapies. Recently, rifabutin has been used in combination with a PPI and amoxycillin as a rescue therapy, with satisfactory eradication rates. In addition, a number of new antimicrobial agents are currently under investigation in in vitro studies but the clinical values of these agents needs to be confirmed.

Helicobacter pylori infection: treatment

Current standard treatment regimens for Helicobacter pylori infection provide eradication rates 80 to 90%. These rates have been achieved with a variety of 1-week triple therapies using two antibiotics and an acid suppressant. Antibiotic resistance, which may develop during failed treatment, is becoming increasingly common and has led to studies of new regimens for primary therapy, and new strategies for salvage of failed therapy. Other regimens have been designed and tested with the aim of decreasing the cost of initial therapy or to improve compliance, but abbreviated regimens have high incidence of failure and may add to the problem of resistance. Increasing attention has been paid to the need for, and timing of, the determination of antibiotic resistance of H. pylori isolates either at the time of initial diagnosis or after treatment failure. New, simpler, and noninvasive methods are offered for follow-up to determine if eradication has been successful. Treatment regimens should be chosen based on local drug susceptibility patterns and the availability of approved therapeutic agents in each country. Established indications for testing for H. pylori and administering therapy include active or inactive peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, as well as hyperplastic polyps, hyperplastic gastropathy, postendoscopic resection for gastric malignancy, and acute H. pylori gastritis. It is now largely accepted that noninvestigated dyspepsia is an indication for testing for and treating H. pylori, but that dyspeptic symptoms shown not to be associated with ulcer (nonulcer dyspepsia) do not now provide an indication for testing. Controversial or unresolved indications for testing and treating include planned use of chronic antisecretory therapy, planned use of nonsteroidal anti-inflammatory drugs, and use as a general approach to the prevention of gastric cancer.

Review article: alternative antibacterial agents for Helicobacter pylori eradication

Standard eradication therapies against Helicobacter pylori appear to be effective in most cases, but in clinical practice a failure rate higher than the 5-10% reported in clinical trials is often observed. Among the various reasons responsible for therapeutic failure, antibiotic resistance is becoming a major issue in some countries. A range of different antibacterial agents is currently under investigation: several macrolides, new fluoroquinolones, furazolidone and rifabutin. Although not formally tested in refractory cases, azithromycin, spiromycin, levofloxacin and furazolidone represent the most promising antibacterial agents for possible inclusion in eradication regimens. Rifabutin has been evaluated in H. pylori infections resistant to standard therapies. Although very effective, the drug is expensive and its use should be restricted to the most difficult cases to avoid the development of rifabutin resistance in Mycobacterium spp.