Successful short-term suppression of clarithromycin-resistant Mycobacterium avium complex bacteremia in AIDS. California Collaborative Treatment Group.
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During a randomized study of clarithromycin plus clofazimine with or without ethambutol in patients with AIDS and Mycobacterium avium complex (MAC) bacteremia, eight participants received additional antimycobacterial drugs following the detection of a clarithromycin-resistant isolate (MIC, > 8 micrograms/mL). A macrolide (seven received clarithromycin, one azithromycin) and clofazimine were continued; additional treatment included various combinations of ethambutol, ciprofloxacin, amikacin, and rifabutin. After the detection of a resistant isolate and before receipt of additional antimycobacterials, the median peak MAC colony count in blood was 105 cfu/mL (range, 8-81,500 cfu/mL). After additional antimycobacterials, the median nadir MAC colony count was 5 cfu/mL (range, 0-110 cfu/mL). Five (63%) of eight patients had a > or = 1 log10 decrease, including two who achieved negative blood cultures; all of these responses occurred in patients originally assigned to clarithromycin plus clofazimine. Treatment of clarithromycin-resistant MAC bacteremia that emerges during clarithromycin-based treatment can decrease levels of bacteremia and transiently sterilize blood cultures. (+info)
Multiplex sequence analysis demonstrates the competitive growth advantage of the A-to-G mutants of clarithromycin-resistant Helicobacter pylori.
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Clarithromycin resistance in Helicobacter pylori is due to point mutation within the 23S rRNA. We examined the growth rates of different types of site-directed mutants and demonstrated quantitatively the competitive growth advantage of A-to-G mutants over other types of mutants by a multiplex sequencing assay. The results provide a rational explanation of why A-to-G mutants are predominantly observed among clarithromycin-resistant clinical isolates. (+info)
Direct detection of Helicobacter pylori resistance to macrolides by a polymerase chain reaction/DNA enzyme immunoassay in gastric biopsy specimens.
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BACKGROUND: The increasing use of macrolides especially in the treatment of Helicobacter pylori infection has led to an increase in resistant strains. The resistance of H pylori to macrolides, especially clarithromycin, is one of the major causes of eradication failure. In H pylori, clarithromycin resistance is due to point mutations localised in domain V of 23S rRNA. AIM: To develop a molecular technique based on amplification of a relevant fragment of the 23S rRNA and colorimetric hybridisation in liquid phase to detect directly in biopsy specimens the type of mutation associated with resistance of H pylori to clarithromycin. METHODS: Gastric biopsy samples from 61 patients were submitted to this test. The results were compared with standard methods (determination of minimal inhibition concentration, polymerase chain reaction/restriction fragment length polymorphism, and/or DNA sequencing) in order to evaluate the test and to define the cut off values, specificity, and sensitivity. RESULTS: The 14 biopsy samples in which H pylori was not detected did not give a positive result in any assay, and the 14 samples harbouring strains susceptible to clarithromycin gave a positive result with the wild type probe as expected. The 33 biopsy specimens containing resistant strains always gave a positive signal with one of the probes detecting resistant organisms, but in eight cases they also reacted with the wild type probe, indicating that a mixture of resistant and susceptible organisms was present. CONCLUSION: The importance of this new assay is that it allows the detection of multiple genotypes corresponding to either heterogeneous genotypes or mixed infections. Moreover, it allows in a single step not only the detection of H pylori but also the determination of its susceptibility to clarithromycin directly in biopsy specimens without the need for culture. (+info)
Eradication of Helicobacter pylori in functional dyspepsia: randomised double blind placebo controlled trial with 12 months' follow up. The Optimal Regimen Cures Helicobacter Induced Dyspepsia (ORCHID) Study Group.
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OBJECTIVES: To determine whether eradication of Helicobacter pylori relieves the symptoms of functional dyspepsia. DESIGN: Multicentre randomised double blind placebo controlled trial. SUBJECTS: 278 patients infected with H pylori who had functional dyspepsia. SETTING: Predominantly secondary care centres in Australia, New Zealand, and Europe. INTERVENTION: Patients randomised to receive omeprazole 20 mg twice daily, amoxicillin 1000 mg twice daily, and clarithromycin 500 mg twice daily or placebo for 7 days. Patients were followed up for 12 months. MAIN OUTCOME MEASURES: Symptom status (assessed by diary cards) and presence of H pylori (assessed by gastric biopsies and 13C-urea breath testing using urea labelled with carbon-13). RESULTS: H pylori was eradicated in 113 patients (85%) in the treatment group and 6 patients (4%) in the placebo group. At 12 months follow up there was no significant difference between the proportion of patients treated successfully by intention to treat in the eradication arm (24%, 95% confidence interval 17% to 32%) and the proportion of patients treated successfully by intention to treat in the placebo group (22%, 15% to 30%). Changes in symptom scores and quality of life did not significantly differ between the treatment and placebo groups. When the groups were combined, there was a significant association between treatment success and chronic gastritis score at 12 months; 41/127 (32%) patients with no or mild gastritis were successfully treated compared with 21/123 (17%) patients with persistent gastritis (P=0. 008). CONCLUSION: No convincing evidence was found that eradication of H pylori relieves the symptoms of functional dyspepsia 12 months after treatment. (+info)
Altered expression profile of the surface glycopeptidolipids in drug-resistant clinical isolates of Mycobacterium avium complex.
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Members of the Mycobacterium avium complex are the most frequently encountered opportunistic bacterial pathogens among patients in the advanced stage of AIDS. Two clinical isolates of the same strain, numbers 397 and 417, were obtained from an AIDS patient with disseminated M. avium complex infection before and after treatment with a regimen of clarithromycin and ethambutol. To identify the biochemical consequence of drug treatment, the expression and chemical composition of their major cell wall constituents, the arabinogalactan, lipoarabinomannan, and the surface glycopeptidolipids (GPL), were critically examined. Through thin layer chromatography, mass spectrometry, and chemical analysis, it was found that the GPL expression profiles differ significantly in that several apolar GPLs were overexpressed in the clinically resistant 417 isolate at the expense of the serotype 1 polar GPL, which was the single predominant band in the ethambutol-susceptible 397 isolate. Thus, instead of additional rhamnosylation on the 6-deoxytalose (6-dTal) appendage to give the serotype 1-specific disaccharide hapten, the accumulation of this nonextended apolar GPL probably provided more precursor substrate available for further nonsaccharide substitutions including a higher degree of O-methylation to give 3-O-Me-6-dTal and the unusual 4-O-sulfation on 6-dTal. Further data showed that this alteration effectively neutralized ethambutol, which is known to inhibit arabinan synthesis. Thus, in contrast with derived Emb-resistant mutants of Mycobacterium smegmatis or Mycobacterium tuberculosis, which are devoid of a surface GPL layer, the lipoarabinomannan from resistant 417 isolate grown in the presence of this drug was not apparently truncated. (+info)
Treatment of Helicobacter pylori and Chlamydia pneumoniae infections decreases fibrinogen plasma level in patients with ischemic heart disease.
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BACKGROUND: Chronic Chlamydia pneumoniae and Helicobacter pylori infections could be a risk factor for ischemic heart disease (IHD), possibly by increasing fibrinogen levels. The aim of our study was to evaluate changes in fibrinogen level in patients with IHD and H pylori and/or C pneumoniae positivity randomly assigned to antibiotic treatment. METHODS AND RESULTS: Eighty-four patients with chronic IHD, H pylori and/or C pneumoniae antibodies, and normal acute-phase reactants were randomly assigned to treatment or no treatment. Treatment consisted of omeprazole, clarithromycin, and tinidazole in H pylori-positive patients and clarithromycin alone in C pneumoniae-positive patients. The effect of treatment and other baseline variables on fibrinogen levels, determined at 6 months, was evaluated by multivariate analysis. Treatment significantly reduced fibrinogen level at 6 months in the overall study population and in the groups of patients divided according to H pylori or C pneumoniae positivity. In the 43 treated patients, mean (+/-SD) basal fibrinogen was 3.65+/-0.58 g/L, and mean final fibrinogen was 3. 09+/-0.52 g/dL (P<0.001), whereas in the 41 untreated patients, mean basal and final fibrinogen levels were 3.45+/-0.70 and 3.61+/-0.71 g/L, respectively. The largest decrease was observed in patients with both infections. Fibrinogen changes were also significantly and negatively correlated with age. CONCLUSIONS: Our data suggest that a short, safe, and effective course of antibiotic therapy might be suggested as a means of interacting with an "emerging" risk factor. (+info)
BACKGROUND: Although many combination therapies have been proposed, there is still interest in identifying simple, inexpensive, effective protocols that have high rates of success. AIM: To investigate the role of the new soluble form of bismuth, ranitidine bismuth citrate, in twice-a-day therapy for Helicobacter pylori infection. METHODS: Patients with histologically and culture proven H. pylori infection received ranitidine bismuth citrate 400 mg, tetracycline HCl 500 mg, and clarithromycin 500 mg, each b.d. for 14 days, followed by 300 mg ranitidine once a day for 4 additional weeks. Outcome was assessed 4 or more weeks after the end of antimicrobial therapy by repeat endoscopy with histology and culture (49 patients) or urea breath testing (14 patients). RESULTS: Sixty-three patients completed the therapy, 59 men and four women (average age 56.7 years; range 31-75 years). All patients had clarithromycin-susceptible strains prior to therapy. H. pylori infection was cured in 94% (95% CI: 85-98%). There was a therapy failure in one patient who took the medicine for only 1 day and stopped because of side-effects. Three of the isolates from treatment failures were available post-failure; two were clarithromycin-resistant and one was susceptible. Side-effects were severe in two patients (3%) and moderate in three (primarily diarrhoea). CONCLUSIONS: Twice-a-day ranitidine bismuth citrate, tetracycline, clarithromycin triple therapy was well tolerated and effective for the treatment of H. pylori infection in patients with clarithromycin-susceptible H. pylori. (+info)
The DU-MACH study: eradication of Helicobacter pylori and ulcer healing in patients with acute duodenal ulcer using omeprazole based triple therapy.
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AIM: To investigate the efficacy of two omeprazole triple therapies for the eradication of Helicobacter pylori, ulcer healing and ulcer relapse during a 6-month treatment-free period in patients with active duodenal ulcer. METHODS: This was a double-blind, randomized study in 15 centres across Canada. Patients (n = 149) were randomized to omeprazole 20 mg once daily (O) or one of two 1-week b. d. eradication regimens: omeprazole 20 mg, metronidazole 400 mg and clarithromycin 250 mg (OMC) or omeprazole 20 mg, amoxycillin 1000 mg and clarithromycin 500 mg (OAC). All patients were treated for three additional weeks with omeprazole 20 mg once daily. Ulcer healing was assessed by endoscopy after 4 weeks of study therapy. H. pylori eradication was determined by a 13C-urea breath test and histology, performed at pre-entry, at 4 weeks after the end of all therapy and at 6 months. RESULTS: The intention-to-treat (intention-to-treat) analysis contained 146 patients and the per protocol (per protocol) analysis, 114 patients. The eradication rates were (intention-to-treat/per protocol): OMC-85% and 92%, OAC-78% and 87% and O-0% (O). Ulcer healing (intention-to-treat) was greater than 90% in all groups. The differences in the eradication and relapse rates between O vs. OMC and O vs. OAC were statistically significant (all, P < 0.001). Treatment was well tolerated and compliance was high. CONCLUSION: The OMC and OAC 1-week treatment regimens are safe and effective for eradication, healing and the prevention of relapse in duodenal ulcer patients. (+info)