N-acetylcysteine, a novel treatment for Helicobacter pylori infection

Antibiotic Resistance of Helicobacter pylori: Mechanisms and Clinical Implications

Helicobacter pylori is a pathogenic bacterium associated with various gastrointestinal diseases, including chronic gastritis, peptic ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. The increasing rates of H. pylori antibiotic resistance and the emergence of multidrug-resistant strains pose significant challenges to its treatment. This comprehensive review explores the mechanisms underlying the resistance of H. pylori to commonly used antibiotics and the clinical implications of antibiotic resistance. Additionally, potential strategies for overcoming antibiotic resistance are discussed. These approaches aim to improve the treatment outcomes of H. pylori infections while minimizing the development of antibiotic resistance. The continuous evolution of treatment perspectives and ongoing research in this field are crucial for effectively combating this challenging infection.

Gill Mucus and Gill Mucin O-glycosylation in Healthy and Amebic Gill Disease-Affected Atlantic Salmon

Amoebic gill disease (AGD) causes poor performance and death in salmonids. Mucins are mainly comprised by carbohydrates and are main components of the mucus covering the gill. Since glycans regulate pathogen binding and growth, glycosylation changes may affect susceptibility to primary and secondary infections. We investigated gill mucin O-glycosylation from Atlantic salmon with and without AGD using liquid chromatography–mass spectrometry. Gill mucin glycans were larger and more complex, diverse and fucosylated than skin mucins. Confocal microscopy revealed that fucosylated mucus coated sialylated mucus strands in ex vivo gill mucus. Terminal HexNAcs were more abundant among O-glycans from AGD-affected Atlantic salmon, whereas core 1 structures and structures with acidic moieties such as N-acetylneuraminic acid (NeuAc) and sulfate groups were less abundant compared to non-infected fish. The fucosylated and NeuAc-containing O-glycans were inversely proportional, with infected fish on the lower scale of NeuAc abundance and high on fucosylated structures. The fucosylated epitopes were of three types: Fuc-HexNAc-R, Gal-[Fuc-]HexNAc-R and HexNAc-[Fuc-]HexNAc-R. These blood group-like structures could be an avenue to diversify the glycan repertoire to limit infection in the exposed gills. Furthermore, care must be taken when using skin mucus as proxy for gill mucus, as gill mucins are distinctly different from skin mucins.

Dietary prophage inducers and antimicrobials: toward landscaping the human gut microbiome

The approximately 10¹¹ viruses and microbial cells per gram of fecal matter (dry weight) in the large intestine are important to human health. The responses of three common gut bacteria species, and one opportunistic pathogen, to 117 commonly consumed foods, chemical additives, and plant extracts were tested. Many compounds, including Stevia rebaudiana and bee propolis extracts, exhibited species-specific growth inhibition by prophage induction. Overall, these results show that various foods may change the abundances of gut bacteria by modulating temperate phage and suggests a novel path for landscaping the human gut microbiome.

Flavodoxins as Novel Therapeutic Targets against Helicobacter pylori and Other Gastric Pathogens

Flavodoxins are small soluble electron transfer proteins widely present in bacteria and absent in vertebrates. Flavodoxins participate in different metabolic pathways and, in some bacteria, they have been shown to be essential proteins representing promising therapeutic targets to fight bacterial infections. Using purified flavodoxin and chemical libraries, leads can be identified that block flavodoxin function and act as bactericidal molecules, as it has been demonstrated for Helicobacter pylori (Hp), the most prevalent human gastric pathogen. Increasing antimicrobial resistance by this bacterium has led current therapies to lose effectiveness, so alternative treatments are urgently required. Here, we summarize, with a focus on flavodoxin, opportunities for pharmacological intervention offered by the potential protein targets described for this bacterium and provide information on other gastrointestinal pathogens and also on bacteria from the gut microbiota that contain flavodoxin. The process of discovery and development of novel antimicrobials specific for Hp flavodoxin that is being carried out in our group is explained, as it can be extrapolated to the discovery of inhibitors specific for other gastric pathogens. The high specificity for Hp of the antimicrobials developed may be of help to reduce damage to the gut microbiota and to slow down the development of resistant Hp mutants.

Helicobacter pylori recrudescence and its influencing factors

Helicobacter pylori (H pylori) is known as one of the most common infectious pathogens, with high infection and recurrence rates worldwide. The prevalence of H pylori is up to 90% in developing countries, while the annual recurrence rate is much higher than that in developed countries. Recurrence can occur either by recrudescence or reinfection. Compared with reinfection, the time window for recrudescence is generally shorter, followed by the recurrence of H pylori–associated diseases in the short‐term. Many factors are involved in the H pylori reinfection, such as the prevalence of H pylori infection, living conditions and economic development, health conditions and so forth. Previous studies focused less on H pylori recrudescence. Therefore, the influencing factors for H pylori recrudescence needed further exploration. This study reviewed the recrudescence of H pylori infection and its influencing factors.

Interleukin 4 induces rapid mucin transport, increases mucus thickness and quality and decreases colitis and Citrobacter rodentium in contact with epithelial cells

Citrobacter rodentium infection is a murine model for pathogenic intestinal Escherichia coli infection. C. rodentium infection causes an initial decrease in mucus layer thickness, followed by an increase during clearance. We aimed to identify the cause of these changes and to utilize this naturally occurring mucus stimulus to decrease pathogen impact and inflammation. We identified that mucin production and speed of transport from Golgi to secretory vesicles at the apical surface increased concomitantly with increased mucus thickness. Of the cytokines differentially expressed during increased mucus thickness, IFN-γ and TNF-α decreased the mucin production and transport speed, whereas IL-4, IL-13, C. rodentium and E. coli enhanced these aspects. IFN-γ and TNF-α treatment in combination with C. rodentium and pathogenic E. coli infection negatively affected mucus parameters in vitro, which was relieved by IL-4 treatment. The effect of IL-4 was more pronounced than that of IL-13, and in wild type mice, only IL-4 was present. Increased expression of Il-4, Il-4-receptor α, Stat6 and Spdef during clearance indicate that this pathway contributes to the increase in mucin production. In vivo IL-4 administration initiated 10 days after infection increased mucus thickness and quality and decreased colitis and pathogen contact with the epithelium. Thus, during clearance of infection, the concomitant increase in IL-4 protects and maintains goblet cell function against the increasing levels of TNF-α and IFN-γ. Furthermore, IL-4 affects intestinal mucus production, pathogen contact with the epithelium and colitis. IL-4 treatment may thus have therapeutic benefits for mucosal healing.

Protective effect of N-acetylcysteine in prosthetic joint infection: A nationwide population-based cohort study

PURPOSE

This nationwide population-based retrospective cohort study evaluated the protective effect of N-acetylcysteine against prosthetic joint infection after hip or knee joint replacement.

METHODS

Patients receiving N-acetylcysteine after hip or knee joint replacement between 2000 and 2015 were identified from the Taiwan National Health Insurance Research Database. Each patient receiving N-acetylcysteine was matched to four controls based on age, sex, and index year. All subjects were followed-up from the index date to December 31, 2015. The Cox proportional hazards regression model was used to assess the risk of prosthetic joint infection.

RESULTS

A total of 1478 patients were included in the study group, and 5912 matched subjects not receiving N-acetylcysteine were included in the control group. After adjusting for age, sex, insured premium, comorbidities, and immunosuppressive agent use, no significant difference in the risk of prosthetic joint infection was found between the two groups. A higher N-acetylcysteine dose (>360 cumulative defined daily dose) significantly decreased the risk of prosthetic joint infection (adjusted hazard ratio = 0.891; 95% confidence interval = 0.599-0.989; p = 0.042). The protective effect of N-acetylcysteine was observed only in the group of prosthetic joint infection within 5 years (adjusted hazard ratio = 0.801; 95% confidence interval = 0.581-0.980; p = 0.040).

CONCLUSIONS

High cumulative dose of N-acetylcysteine (>360 cumulative defined daily dose) can effectively reduce the risk of prosthetic joint infection in patients undergoing knee or hip joint replacement surgery within 5 years.

Helicobacter pylori Biofilm Formation and Its Potential Role in Pathogenesis

Despite decades of effort, Helicobacter pylori infections remain difficult to treat. Over half of the world's population is infected by H. pylori, which is a major cause of duodenal and gastric ulcers as well as gastric cancer. During chronic infection, H. pylori localizes within the gastric mucosal layer, including deep within invaginations called glands; thanks to its impressive ability to survive despite the harsh acidic environment, it can persist for the host's lifetime. This ability to survive and persist in the stomach is associated with urease production, chemotactic motility, and the ability to adapt to the fluctuating environment. Additionally, biofilm formation has recently been suggested to play a role in colonization. Biofilms are surface-associated communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances. Biofilms pose a substantial health risk and are key contributors to many chronic and recurrent infections. This link between biofilm-associated bacteria and chronic infections likely results from an increased tolerance to conventional antibiotic treatments as well as immune system action. The role of this biofilm mode in antimicrobial treatment failure and H. pylori survival has yet to be determined. Furthermore, relatively little is known about the H. pylori biofilm structure or the genes associated with this mode of growth. In this review, therefore, we aim to highlight recent findings concerning H. pylori biofilms and the molecular mechanism of their formation. Additionally, we discuss the potential roles of biofilms in the failure of antibiotic treatment and in infection recurrence.

Effects of N-acetylcysteine on First-Line Sequential Therapy for Helicobacter pylori Infection: A Randomized Controlled Pilot Trial

Background/Aims

To evaluate the adjuvant effects of N-acetylcysteine (NAC) on first-line sequential therapy (SQT) for Helicobacter pylori infection.

Methods

Patients with H. pylori infections were randomly assigned to receive sequential therapy with (SQT+NAC group, n=49) or without (SQT-only group, n=50) NAC. Sequential therapy consisted of rabeprazole 20 mg and amoxicillin 1 g for the first 5 days, followed by rabeprazole 20 mg, clarithromycin 500 mg and metronidazole 500 mg for the remaining 5 days; all drugs were administered twice daily. For the SQT+NAC group, NAC 400 mg bid was added for the first 5 days of sequential therapy. H. pylori eradication was evaluated 4 weeks after the completion of therapy.

Results

The eradication rates by intention-to-treat analysis were 58.0% in the SQT-only group and 67.3% in the SQT+NAC group (p=0.336). The eradication rates by per-protocol analysis were 70.0% in the SQT-only group and 80.5% in the SQT+NAC group (p=0.274). Compliance was very good in both groups (SQT only/SQT+NAC groups: 95.2%/100%, p=0.494). There was no significant difference in the adverse event rates between groups (SQT-only/SQT+NAC groups: 26.2%/26.8%, p=0.947).

Conclusions

The H. pylori eradication rate was numerically higher in the SQT+NAC group than in the SQT-only group. As our data did not reach statistical significance, larger trials are warranted.

An Additive Effect of Oral N-Acetyl Cysteine on Eradication of Helicobacter pylori

Background. Helicobacter pylori is highly adapted to the gastric environment where it lives within or beneath the gastric mucous layer. The aim of this study was to evaluate whether the addition of N-acetyl cysteine to the treatment regimen of H. pylori infection would affect eradication rates of the disease. Methods. A total of 79 H. pylori positive patients were randomized to two therapeutic groups. Both groups received a 14-day course of three-drug regimen including amoxicillin/clarithromycin/omeprazole. Experimental group (38 subjects) received NAC, and control group (41 subjects) received placebo, besides three-drug regimen. H. pylori eradication was evaluated by urea breath test at least 4 weeks after the cessation of therapy. Results. The rate of H. pylori eradication was 72.9% and 60.9% in experimental and control groups, respectively (P = 0.005). By logistic regression modeling, female gender (OR 3.68, 95% CI: 1.06–5.79; P = 0.040) and treatment including NAC (OR 1.88, 95% CI: 0.68–3.15; P = 0.021) were independent factors associated with H. pylori eradication. Conclusion. The results of the present study show that NAC has an additive effect on the eradication rates of H. pylori obtained with three-drug regimen and appears to be a promising means of eradicating H. pylori infection.

N-acetylcysteine selectively antagonizes the activity of imipenem in Pseudomonas aeruginosa by an OprD-mediated mechanism

The modulating effect of N-acetylcysteine (NAC) on the activity of different antibiotics has been studied in Pseudomonas aeruginosa. Our results demonstrate that, in contrast to previous reports, only the activity of imipenem is clearly affected by NAC. MIC and checkerboard determinations indicate that the NAC-based modulation of imipenem activity is dependent mainly on OprD. SDS-PAGE of outer membrane proteins (OMPs) after NAC treatments demonstrates that NAC does not modify the expression of OprD, suggesting that NAC competitively inhibits the uptake of imipenem through OprD. Similar effects on imipenem activity were obtained with P. aeruginosa clinical isolates. Our results indicate that imipenem-susceptible P. aeruginosa strains become resistant upon simultaneous treatment with NAC and imipenem. Moreover, the generality of the observed effects of NAC on antibiotic activity was assessed with two additional bacterial species, Escherichia coli and Acinetobacter baumannii. Caution should be taken during treatments, as the activity of imipenem may be modified by physiologically attainable concentrations of NAC, particularly during intravenous and nebulized regimes.

N-acetyl cysteine as an adjunct to standard anti-Helicobacter pylori eradication regimen in patients with dyspepsia: A prospective randomized, open-label trial

Background:

Increasing antibiotic resistance of Helicobacter pylori (H. pylori) which is associated with diseases of the upper gastrointestinal tract, has made alternative treatments necessary. This study compares the efficacy of adding N-acetyl cysteine (NAC) to standard regimen for H. pylori eradication.

Materials and Methods:

We conducted a randomized, open-label trial, comparing the efficacy of 14 days of quadruple therapy with Amoxicillin, Bismuth citrate, Omeprazole, Clarithromycin (group A) versus 14 days of above regimen plus NAC (group B) in adult patients with dyspepsia. Primary objective was H. pylori eradication. Compliance and side effects were determined by questionnaires. Our analysis was by intention-to-treat (ITT) and per-protocol. This study is registered with www.IRCT.ir, number: IRCT201201078634N1.

Result:

A total of 121 participants aged 21-76 years with a mean age of 44.5 ± 14.1, and 52.9% female, were randomly allocated a treatment: 60 with 14-day standard therapy and 61 with 14-day standard therapy with NAC. The eradication rate in groups A and B with ITT analyses was 49/60 (81.7%; 95% [confidence intervals] CI = 71.6-91.8%) and 50/61 (82%; 95% CI = 72-91.9%), respectively (P = 0.96). In per-protocol analysis, the rate of H. pylori eradication in groups A and B was 45/54 (83.3%; 95% CI = 73.1-93.6%) and 45/53 (84.9%; 95% CI = 74.9-94.9%), respectively (P = 0.82). Minor well tolerated side effects were reported in 15 (34.9%) and 21 (35.6%) patients of groups A and B, respectively, and only one therapy cessation in group A was created.

Conclusion:

Standard 14-day triple-drug therapy with NAC is not preferable to standard drug regimens for H. pylori infection.

Efficacy and pharmacological mechanism of pronase-enhanced low-dose antibiotics for Helicobacter pylori eradication

This study examined the efficacy and pharmacological mechanism of pronase-assisted low-dose antibiotics for eradication of Helicobacter pylori. Mongolian gerbils infected with H. pylori received 7-day treatment (omeprazole, different concentrations of pronase, amoxicillin, and clarithromycin), and the efficacy was assessed using the eradication rate and the colonization of H. pylori. In Mongolian gerbils orally administered pronase, the thickness of the gastric mucous layer (GML) was examined using immunohistochemical and alcian blue staining, and the concentrations of amoxicillin in gastric tissue and serum were detected using high-performance liquid chromatography (HPLC). The eradication rates were 80.0% (12/15) in the high-pronase quadruple group (HPQG) and 86.7% (13/15) in the high-antibiotic group (HAG) (P = 1.000). The antibiotic dose in the HPQG was only 1/20 that in the HAG. Thirty minutes after oral treatment with pronase, the sticky protein of the GML was hydrolyzed, and the GML became thinner. Higher amoxicillin concentrations in both the gastric tissue and serum were observed in the pronase group than in the Am10 group. The concentration of amoxicillin in the Am10-plus-Pr108 group in gastric tissue was 3.8 times higher than in the Am10 group in 5 min. Together, these data suggest that pronase significantly reduced the dose of antibiotics used in H. pylori eradication. The pharmacological mechanism is likely pronase removal of the mucus layer, promoting chemical factor (i.e., gastric acid and pepsinogen) distribution and increasing the antibiotic concentrations in the deep GML, which acted on H. pylori collectively. Thus, pronase may enhance the level of antibiotics for eradication of H. pylori in the clinic.

In vitro evaluation of antimicrobial features of vasopressors

BACKGROUND

Drugs administered as intravenous infusion may be contaminated during several stages of production or preparation. However studies focusing on antibacterial effects of vasopressor drugs are very rare. This study investigates the in vitro antimicrobial activity of the clinically used forms of vasopressors.

MATERIALS AND METHODS

In vitro antimicrobial activities of vasopressor drugs of different concentrations were investigated by using the micro dilution technique. Microorganisms used in the test were Escherichia coli ATCC 25922, Yersinia pseudotuberculosis ATCC 911, Pseudomonas aeruginosa ATCC 10145, Listeria monocytogenes ATCC 43251, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, Bacillus cereus 702 Roma, Mycobacterium smegmatis ATCC607, Candida albicans ATCC 60193, and Saccharomyces cerevisiae RSKK 251. Antibacterial assays were performed in Mueller-Hinton broth at pH 7.3 and antifungal assays were performed in buffered Yeast Nitrogen Base at pH 7.0.

RESULTS

Two different dopamine preparations showed antimicrobial activity. No other study drug showed any antimicrobial activity.

CONCLUSIONS

In our opinion, dopamine's antibacterial effects may be advantageous for inhibiting the spread of bacterial contamination during the preparation of the infusion solutions. However, it is important that strict guidelines regarding the need for sterile equipment and deliverables be adhered to during all procedures performed in the intensive care units.

N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa

Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS). The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer). HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL) in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria.

Pilot study: miscellaneous therapy is highly successful for Helicobacter pylori eradication

BACKGROUND

Success in H. pylori eradication with conventional therapies has decreased to unacceptable levels (≤80%). New schemes of combined treatment are currently needed.

AIM

To test a miscellaneous therapy for H. pylori eradication.

METHODS/PATIENTS

Open-label, pilot, single-centre and prospective study. Patients received a 15-day treatment scheme that consisted of 5 initial days of lansoprazole 30 mg b.d., amoxicillin 1 g b.d., and metronidazole 500 mg t.d.s.; days 6 to 10: lansoprazole 30 mg q.d.s. and metronidazole 500 mg t.d.s.; days 11 to 15: lansoprazole 30 mg b.d., clarithromycin 500 mg b.d. and metronidazole 500 mg t.d.s. Each patient underwent an upper endoscopy before treatment and a second follow-up endoscopy at least 4 weeks after therapy. Success was defined on the basis of an eradication rate following a per-protocol analysis ≥95%. Biopsies before and after therapy were obtained for histological evaluation and rapid urease test.

RESULTS

One hundred and twenty-two patients were enrolled and 118 patients completed the study. The eradication rate for H. pylori with miscellaneous therapy was 94% (confidence Interval (CI) 95%, 90-98.3%) in the per-protocol analysis (PP) and 91% (95% CI, 86-96%) in the intention-to-treat (ITT) analysis. Adherence to treatment was 96% (113 patients). Among patients who completed treatment, 55% presented adverse events, mainly nausea and abdominal pain.

CONCLUSION

A miscellaneous therapy, based on the combination of multiple medications in high doses for 2 weeks, and with gastric pH elevation, is a highly effective treatment as a first-line therapy for the eradication of H. pylori.

Review article: biofilm formation by Helicobacter pylori as a target for eradication of resistant infection

BACKGROUND

Helicobacter pylori is one of the most common causes of bacterial infection in humans. Resistance of this infection to conventional therapies has suggested the role of a biofilm-growing bacterium, which is recalcitrant to many antimicrobial agents.

AIM

To review the current knowledge on biofilm formation by H. pylori and to discuss the implications of this behaviour in the context of human infections and their treatment.

RESULTS

Scanning electron microscopy analysis of gastric biopsies of infected patients demonstrated that H. pylori forms biofilm on the gastric mucosa epithelium. Adaptation to the biofilm environment may produce many persister cells, namely dormant cells, which are highly tolerant to antimicrobials that could account for the recalcitrance of H. pylori infections in vivo. Resistant H. pylori infection has become increasingly common with triple or quadruple therapy, even in the presence of H. pylori strains susceptible to all antibiotics. The mucolytic and thiol-containing antioxidant N-acetylcysteine, associated with antibiotics, was successfully used in clinic for therapy of patients with chronic respiratory tract infections. Consistently, N-acetylcysteine treatment prior to starting antibiotic therapy allowed the disappearance of gastric biofilm in all patients in whom H. pylori was eradicated.

CONCLUSION

Effective strategies targeting H. pylori biofilm infections are possible, through the use of substances degrading components of the biofilm.

Novel combination therapy for the eradication of Helicobacter pylori infection in a mouse model

OBJECTIVE

To investigate the combination therapy, consisting of hyperimmune bovine colostrum, N-acetyl cysteine, zinc and amoxicillin on the eradication of Helicobacter pylori in a mouse model.

MATERIAL AND METHODS

C57BL/6 female mice (6 weeks of age) were inoculated with 0.1 ml of 1×10(9) H. pylori via a single oro-gastric gavage and were left infected for 4 weeks. Mice (n=9/group) were randomly allocated to receive by oral gavage (0.1 ml) HNZ (hyperimmune bovine colostrum+N-acetyl cysteine+zinc), HNZA (HNZ+amoxicillin; A), HNZA2 (2× amoxicillin; A2), HNZA5 (5× amoxicillin; A5), triple therapy (TT) or saline twice daily for 10 days. Bacterial load was assessed by culture. Gastric emptying was assessed by 13C-octanoic acid breath test.

RESULTS

Mice receiving HNZ, HNZA, and HNZA2 have a 22%, 44% and 67% eradication rate, respectively. Eradication rate was 100% with HNZA5, TT and those animals receiving A5 alone. In H. pylori infected mice there was an increased gastric emptying time by 7.9, 3.7, 10.1 and 7.7 min for the TT, HNZ, HNZA2, and HNZA5, respectively, compared to saline.

CONCLUSIONS

HNZ with the addition of a high dose of amoxicillin is effective at eradicating H. pylori in vivo as HNZA1 and HNZA2 did not give raise to eradication. The potency of the novel anti-H. pylori combination therapy may be due to the delayed gastric emptying.

Detailed in vivo analysis of the role of Helicobacter pylori Fur in colonization and disease

Helicobacter pylori persistently colonizes the harsh and dynamic environment of the stomach in over one-half of the world's population and has been identified as a causal agent in a spectrum of pathologies that range from gastritis to invasive adenocarcinoma. The ferric uptake regulator (Fur) is one of the few regulatory proteins that has been identified in H. pylori. Fur regulates genes important for acid acclimation and oxidative stress and has been shown to be important for colonization of H. pylori in both murine and Mongolian gerbil models of infection. To more thoroughly define the role of Fur in vivo, we conducted an extensive temporal analysis of the location of, competitive ability of, and resultant pathology induced by a Deltafur strain in the Mongolian gerbil model of infection and compared the results to results for its wild-type parent. We found that at the earliest time points postinfection, significantly more Deltafur bacteria than wild-type bacteria were recovered. However, this trend was reversed by day 3, when there was significantly increased recovery of the wild-type strain. The increased recovery of the Deltafur strain at 1 day postinfection reflected increased recovery from both the corpus and the antrum of the stomach. When the wild-type strain was allowed to colonize first, the Deltafur strain was unable to compete for colonization at any time postinfection. However, when the Deltafur strain was allowed to colonize first, the wild type efficiently outcompeted the Deltafur strain only at early times postinfection. Finally, we demonstrated that there was a delay in the development and severity of inflammation and pathology of the Deltafur strain in the gastric mucosa even after comparable levels of colonization occurred. Together, these data indicate that H. pylori Fur is most important at early stages of infection and illustrate the importance of the ability of H. pylori to adapt to its constantly fluctuating environment when it is establishing infection, inflammation, and disease.

Treatment of Helicobacter pylori infection with intra-gastric violet light phototherapy: a pilot clinical trial

BACKGROUND AND OBJECTIVE

Helicobacter pylori infects the mucus layer of the human stomach and causes peptic ulcers and adenocarcinoma. We have previously shown that H. pylori accumulates photoactive porphyrins making the organism susceptible to inactivation by light, and that small spot endoscopic illumination with violet light reduced bacterial load in human stomachs. This study assessed the feasibility and safety of whole-stomach intra-gastric violet phototherapy for the treatment of H. pylori infection.

STUDY DESIGN/MATERIALS AND METHODS

A controlled, prospective pilot trial was conducted using a novel light source consisting of laser diodes and diffusing fibers to deliver 408-nm illumination at escalating total fluences to the whole stomach. Eighteen adults (10 female) with H. pylori infection were treated at three U.S. academic endoscopy centers. Quantitative bacterial counts were obtained from biopsies taken from the antrum, body, and fundus, and serial urea breath tests.

RESULTS

The largest reduction in bacterial load was in the antrum (>97%), followed by body (>95%) and fundus (>86%). There was a correlation between log reduction and initial bacterial load in the antrum. There was no dose-response seen with increasing illumination times. The urea breath test results indicated that the bacteria repopulated in days following illumination.

CONCLUSION

Intra-gastric violet light phototherapy is feasible and safe and may represent a novel approach to eradication of H. pylori, particularly in patients who have failed standard antibiotic treatment. This was a pilot study involving a small number of patients. Further research is needed to determine if phototherapy can be effective for eradicating H. pylori.

Effects of laxative and N-acetylcysteine on mucus accumulation, bacterial load, transit, and inflammation in the cystic fibrosis mouse small intestine

The accumulation of mucus in affected organs is characteristic of cystic fibrosis (CF). The CF mouse small intestine has dramatic mucus accumulation and exhibits slower interdigestive intestinal transit. These factors are proposed to play cooperative roles that foster small intestinal bacterial overgrowth (SIBO) and contribute to the innate immune response of the CF intestine. It was hypothesized that decreasing the mucus accumulation would reduce SIBO and might improve other aspects of the CF intestinal phenotype. To test this, solid chow-fed CF mice were treated with an osmotic laxative to improve gut hydration or liquid-fed mice were treated orally with N-acetylcysteine (NAC) to break mucin disulfide bonds. Treatment with laxative or NAC reduced mucus accumulation by 43% and 50%, respectively, as measured histologically as dilation of the intestinal crypts. Laxative and NAC also reduced bacterial overgrowth in the CF intestine by 92% and 63%, respectively. Treatment with laxative normalized small intestinal transit in CF mice, whereas NAC did not. The expression of innate immune response-related genes was significantly reduced in laxative-treated CF mice, whereas there was no significant effect in NAC-treated CF mice. In summary, laxative and NAC treatments of CF mice reduced mucus accumulation to a similar extent, but laxative was more effective than NAC at reducing bacterial load. Eradication of bacterial overgrowth by laxative treatment was associated with normalized intestinal transit and a reduction in the innate immune response. These results suggest that both mucus accumulation and slowed interdigestive small intestinal transit contribute to SIBO in the CF intestine.

A curcumin-based 1-week triple therapy for eradication of Helicobacter pylori infection: something to learn from failure?

BACKGROUND

Curcumin is the principal element of turmeric powder extracted from the root of Curcuma longa. Studies on curcumin have demonstrated some anti-Helicobacter pylori activity as well as immunomodulating properties. N-acetylcysteine and lactoferrin with their respective mucolytic and antibacterial activities might also be effective in H. pylori eradication therapy.

AIM

To determine if a 7-day non-antibiotic therapy comprised of curcumin, lactoferrin, N-acetylcysteine, and pantoprazole was effective for eradication of H. pylori infection and reduction of gastric inflammation, assessed by serum pepsinogens and relief of symptoms.

SUBJECTS AND METHODS

Twenty-five consecutive H. pylori-positive patients (12 males, mean age 50 +/- 12 years, range 31-76) with functional dyspepsia were enrolled. Patients were administered for 7 days curcumin 30 mg b.i.d., bovine lactoferrin 100 mg b.i.d., N-acetylcysteine 600 mg b.i.d., and pantoprazole 20 mg b.i.d. H. pylori status and upper gastrointestinal symptoms were assessed by (13)C-urea breath test and a scale of upper gastrointestinal symptoms intensity (absent, mild, moderate, and severe), as well as a blood test for serum pepsinogens (sPGI, sPGII), gastrin-17 (G-17), and anti-H. pylori IgG (IgG-Hp) at baseline (T0) and after 2 months (T1).

RESULTS

Three of 25 patients (12%) were cured of H. pylori infection. A significant decrease in the overall severity of symptoms (T0: 6, interquartile range [IQR]: 4.5-8; T1: 2, IQR: 2-3; p < or = .001), and sPGII (T0: 16 microg/L, IQR: 13-22; T1: 10 microg/L, IQR: 8-16; p < or = .001) and sPGI (T0: 82 microg/L, IQR: 67-97; T1: 74 microg/L, IQR: 62-94; p = .02) levels were observed after 2 months of the treatment. IgG and G-17 values did not significantly decrease after 2 months.

CONCLUSIONS

This novel therapy was not effective for H. pylori eradication. However, despite the bacterium persistence, significant improvement of dyspeptic symptoms and reduction of serologic signs of gastric inflammation were observed after 2 months at the end of the 7-day treatment schedule.

Premedication with pronase or N-acetylcysteine improves visibility during gastroendoscopy: An endoscopist-blinded, prospective, randomized study

AIM: To assess the efficacy of premedicaton with pronase or N-acetylcysteine (NAC) at 20 min before upper gastrointestinal (UGI) endoscopy and to determine whether pronase or NAC pretreatment influences the reliability of the rapid urease test.

METHODS: A total of 146 patients were prospectively and randomly assigned into the study groups according to different premedications before endoscopy. One endoscopist assessed mucosal visibility (MV) with scores ranged from 1 to 4 at four sites in the stomach. The sum of the MV scores from these four locations was defined as the total mucosal visibility (TMV) score. Identification of H pylori was performed using CLO test, histology, and serology.

RESULTS: The Group with pronase premedication had a significantly lower TMV score than did the groups with gascon and gascon water (p < 0.001 and p < 0.01, respectively). The group with NAC had a significantly lower TMV score than the group with gascon (p < 0.01) and a trend of a lower MV score than the group with gascon water (p = 0.06). The TMV score did not significantly differ between the group with pronase and the group with NAC (p = 0.39 and p = 0.14, respectively). The sensitivity and specificity of the CLO test were 92.5% and 93.9%, respectively, in groups premedicated with pronase and NAC together.

CONCLUSION: Premedication with pronase or NAC at 20 min before UGI endoscopy improves the mucosal visibility of the stomach. Neither pronase nor NAC produces any obvious interference with the CLO test for the identification of H pylori infection.

Acetylcysteine: Helicobacter Pylori Infection

Off-Label Drug Uses — This Hospital Pharmacy feature is extracted from Off-Label DrugFacts, a quarterly publication available from Wolters Kluwer Health. Off-Label DrugFacts is a practitioner-oriented resource for information about specific FDA-unapproved drug uses. This new guide to the literature will enable the health care professional/clinician to quickly identify published studies on off-label uses and to determine if a specific use is rational in a patient care scenario. The most relevant data are provided in tabular form, so the reader can easily identify the scope of information available. A summary of the data—including background, study design, patient population, dosage information, therapy duration, results, safety, and therapeutic considerations—precedes each table of published studies. References direct the reader to the full literature for more comprehensive information prior to patient care decisions. Direct questions or comments regarding “Off-Label Drug Uses” to hospitalpharmacy@drugfacts.com .

N-acetylcysteine -- passe-partout or much ado about nothing?

In experimental studies, the old mucolytic agent N-acetylcysteine (NAC) has had beneficial effects in disorders supposedly linked to oxidative stress. Numerous, mainly small clinical trials with variable doses have yielded inconsistent results in a wide variety of diseases. NAC added to the conventional therapy of human immunodeficiency virus infection might be of benefit; in respect of chronic obstructive pulmonary disease, systematic reviews and meta-analyses suggested that prolonged treatment with NAC is efficacious, but a recent multicentre study has questioned this. In a large intervention trial on cancer recurrence, NAC was ineffective. NAC infusions have been widely used in acute hepatic failure but convincing evidence of its benefits is lacking. A preliminary study reported that NAC is effective in preventing radiocontrast-induced nephropathy but thereafter highly mixed results have been published, and even meta-analyses disagree on its efficacy. In intensive care NAC has mostly been a disappointment but recently it has 'given promises' in surgery with cardiopulmonary bypass. NAC therapy is routine only in paracetamol intoxication.

Role of N-acetylcysteine in the management of COPD

The importance of the underlying local and systemic oxidative stress and inflammation in chronic obstructive pulmonary disease (COPD) has long been established. In view of the lack of therapy that might inhibit the progress of the disease, there is an urgent need for a successful therapeutic approach that, through affecting the pathological processes, will influence the subsequent issues in COPD management such as lung function, airway clearance, dyspnoea, exacerbation, and quality of life. N-acetylcysteine (NAC) is a mucolytic and antioxidant drug that may also influence several inflammatory pathways. It provides the sulfhydryl groups and acts both as a precursor of reduced glutathione and as a direct reactive oxygen species (ROS) scavenger, hence regulating the redox status in the cells. The changed redox status may, in turn, influence the inflammation-controlling pathways. Moreover, as a mucolytic drug, it may, by means of decreasing viscosity of the sputum, clean the bronchi leading to a decrease in dyspnoea and improved lung function. Nevertheless, as successful as it is in the in vitro studies and in vivo studies with high dosage, its actions at the dosages used in COPD management are debatable. It seems to influence exacerbation rate and limit the number of hospitalization days, however, with little or no influence on the lung function parameters. Despite these considerations and in view of the present lack of effective therapies to inhibit disease progression in COPD, NAC and its derivatives with their multiple molecular modes of action remain promising medication once doses and route of administration are optimized.

Rifaximin-based regimens for eradication of Helicobacter pylori: a pilot study

BACKGROUND

Triple therapy is the treatment of choice for Helicobacter pylori-infected patients with an eradication rate ranging from 70 to 85%. Poor compliance and antibiotic resistance are the main causes of treatment failure. The aim of the present study was to assess the efficacy of rifaximin, a poorly absorbed antibiotic, for H. pylori eradication.

METHODS

We enrolled 48 consecutive H. pylori-positive patients affected. They were randomized to receive two 7-day rifaximin-based triple therapies: rifaximin tablets 400 mg t.i.d., esomeprazole 40 mg o.d. and clarithromycin 500 mg b.i.d. (CRE) or levofloxacin 500 mg o.d. (LRE). H. pylori eradication was assessed using a (13)C-urea breath test 4 weeks after the end of therapy. Treatment compliance and the incidence of side effects were also evaluated.

RESULTS

No dropouts were observed. The eradication rate both on intention-to-treat and per-protocol analysis did not show significant differences between groups: 58% (14/24 patients) in group 1 and 42% (10/24 patients) in group 2 (p = 0.24, OR 1.96, 95% CI 0.62-6.18). No significant differences in patients' compliance and incidence of side effects were found between groups.

CONCLUSIONS

Rifaximin-based therapy showed optimal compliance but a limited eradication rate compared to standard first-line treatment. Further investigations are needed to evaluate different dosages and combinations.