The safety and efficacy of short course (5-day) moxifloxacin vs. azithromycin in the treatment of patients with acute exacerbation of chronic bronchitis.
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Chronic bronchitis is common among adults and infectious exacerbations contribute considerably to morbidity and mortality. We aimed to compare the safety and efficacy of moxifloxacin to azithromycin for the treatment of patients with acute exacerbations of chronic bronchitis (AECB) of suspected bacterial origin. Between October 1998 and April 1999, 567 patients with AECB were enrolled at 37 centers across the United States and Canada of which 280 (49%) had acute bacterial exacerbation of chronic bronchitis (i.e. pretherapy pathogen). Patients were randomized to either oral moxifloxacin 400 mg administered once daily for 5 days or azithromycin for 5 days (500 mg qd x 1, then 250 mg qd x 4). For the purpose of study blinding, all patients received encapsulated tablets. The main outcome measure was clinical response at the test-of-cure visit (14-21 days post-therapy). Secondary measures included bacteriologic response and a time-course of bacteriological eradication (one center only). Three patient populations were analysed for efficacy: clinically-valid, microbiologically-valid (i.e. those with a pretherapy pathogen), and intent-to-treat (i.e. received at least one dose of study drug). For the efficacy-valid group, clinical response at the test-of-cure visit was 88% for patients in each treatment group. In 237 microbiologically-valid patients, corresponding clinical resolution rates were 88% for 5-day moxifloxacin vs. 86% for 5-day azithromycin. Bacteriological eradication rates at the end of therapy were 95% for 5-day moxifloxacin and 94% for the azithromycin group. Corresponding eradication rates at the test-of-cure visit were 89% and 86%, respectively. Of note, eradication rates at test-of-cure for Haem. philos influenzae and H. parainfluenzae for moxifloxacin were 97% and 88% compared to 83% and 62% respectively for azithromycin. Among 567 intent-to-treat patients (283 moxifloxacin and 284 azithromycin), drug-related events were reported for 22% and 17%, respectively. Diarrhea and nausea were the most common drug-related events reported in each treatment group. Moxifloxacin 400 mg once daily for 5 days was found to be clinically and bacteriologically equivalent to 5-day azithromycin for the treatment of AECB of proven bacterial etiology. Given its excellent in-vitro activity, especially against antibiotic-resistant respiratory pathogens, and its acceptable safety profile, moxifloxacin should be considered an effective alternative therapy for patients with AECB of suspected bacterial origin. (+info)
Influence of variations in test methods on susceptibility of Haemophilus influenzae to ampicillin, azithromycin, clarithromycin, and telithromycin.
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The National Committee for Clinical Laboratory Standards standard broth microdilution method for testing the susceptibility of Haemophilus influenzae to ampicillin, azithromycin, clarithromycin, and telithromycin was evaluated by altering one variable at a time. Variables that were tested included age of colony for inoculum preparation, inoculum density, test medium, incubation atmosphere, and incubation time. For the macrolide, azalide, and ketolide agents, incubation in 5 to 7% CO(2) most significantly affected the MICs, producing nearly twofold increases for clarithromycin and telithromycin and a greater than threefold increase for azithromycin. For ampicillin, a 10-fold increase in inoculum density increased the geometric mean MICs for beta-lactamase-negative strains from 1. 50 to 2.45 microg/ml. In addition, 206 H. influenzae strains were tested for their susceptibilities to the same drugs by the broth microdilution tests in two media, as well as by agar dilution tests, disk diffusion tests, and Etests, on six different agar media. The three standard methods with Haemophilus test medium (HTM) compared favorably with each other except for a high minor discrepancy rate (27%) by the disk diffusion test with ampicillin and clarithromycin. Agar dilution test MICs on the five comparative media were generally higher than those on HTM agar but were only rarely more than one twofold concentration higher. Etest MICs of azithromycin and telithromycin were more than twofold higher than agar dilution and broth microdilution MICs on HTM; ampicillin Etest MICs were nearly twofold lower. The use of media other than HTM agar appears to have a minimal effect on susceptibility test results for the ketolide, azalide, or macrolide drugs that we tested against H. influenzae. (+info)
Serum and WBC pharmacokinetics of 1500 mg of azithromycin when given either as a single dose or over a 3 day period in healthy volunteers.
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Owing to azithromycin's prolonged half-life, shorter and shorter dosage regimens are being studied for treatment of respiratory tract infections. Previous studies have concluded that the 3 and 5 day (1.5 g total) regimens not only provide at least equal serum and WBC exposures but also equal efficacy rates. An earlier clinical study using the entire 1.5 g dose at once or the current 3 day regimen in patients with atypical pneumonia noted equal efficacy. Similar trials are currently underway in both adult and paediatric populations. The goal of the present study was to investigate whether there were equal serum and WBC exposures when azithromycin was dosed as the current 3 day regimen or as a single large dose. Equal exposures would help validate future clinical trials of single dose regimens. Twelve healthy volunteers received both azithromycin regimens (1.5 g single dose and 500 mg/day for 3 days) in random order. Serum and WBC samples were collected at baseline and repeatedly for 10 days following the first dose of each regimen. Serum samples were assayed via HPLC (CV% < 10) and WBC samples via liquid chromatography/mass spectrometry (CV% < 10). Data were modelled using noncompartmental methods. Statistics were via ANOVA with significance defined as P < 0.05. All subjects completed both regimens with minimal incidence of adverse effects. Serum data [mean (range)] demonstrated no significant difference in exposure between the two regimens [single 13.1 (3.02-20.6) mg x h/L versus 3 day 11.2 (2.98-24.5) mg x h/L: P = 0.12], although it favoured the shorter regimen. WBC results demonstrated much higher exposures than seen with serum, but no significant difference between the two regimens was identified. These results suggest that a single oral 1.5 g regimen of azithromycin for respiratory tract infections should provide exposure at least equal to currently approved treatment regimens. (+info)
Activity of buforin II alone and in combination with azithromycin and minocycline against Cryptosporidium parvum in cell culture.
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The in vitro anti-cryptosporidial activity of buforin II alone and in combination with azithromycin and minocycline was investigated. Buforin II showed moderate activity, which increased with increasing concentration to 55.7% suppression of growth at 20 microM. Moreover, its activity was enhanced when it was combined with either azithromycin or minocycline with >90% parasite reduction at the highest concentration tested. Buforin II may be active in inhibiting Cryptosporidium parvum growth in vitro upon combination with either azithromycin or minocycline. (+info)
Chlamydia pneumoniae infection in circulating human monocytes is refractory to antibiotic treatment.
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BACKGROUND: Recovery of the intracellular bacterium Chlamydia pneumoniae from atherosclerotic plaques has initiated large studies on antimicrobial therapy in coronary artery disease. The basic concept that antibiotic therapy may eliminate and prevent vascular infection was evaluated in vitro and in vivo by examining the antibiotic susceptibility of C pneumoniae in circulating human monocytes, which are thought to transport chlamydiae from the respiratory tract to the vascular wall. METHODS AND RESULTS: Blood monocytes (CD14+) from 2 healthy volunteers were obtained before and after oral treatment with azithromycin or rifampin and then inoculated with a vascular C pneumoniae strain and continuously cultured in the presence of the respective antibiotic. Progress of infection and chlamydial viability was assessed by immunogold-labeling and detection of C pneumoniae-specific mRNA transcripts. Circulating monocytes from patients undergoing treatment with experimental azithromycin for coronary artery disease were examined for C pneumoniae infection by cell culture. Antibiotics did not inhibit chlamydial growth within monocytes. Electron microscopy showed development of chlamydial inclusion bodies. Reverse transcription-polymerase chain reaction demonstrated continuous synthesis of chlamydial mRNA for 10 days without lysis of the monocytes. The in vivo presence of viable pathogen not eliminated by azithromycin was shown by cultural recovery of C pneumoniae from the circulating monocytes of 2 patients with coronary artery disease. CONCLUSIONS: C pneumoniae uses monocytes as a transport system for systemic dissemination and enters a persistent state not covered by an otherwise effective antichlamydial treatment. Prevention of vascular infection by antichlamydial treatment may be problematic: circulating monocytes carrying a pathogen with reduced antimicrobial susceptibility might initiate reinfection or promote atherosclerosis by the release of proinflammatory mediators. (+info)
Azithromycin and gentamicin therapy for the treatment of humans with brucellosis.
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Ten patients with brucellosis were treated with azithromycin and gentamicin to assess the treatment's safety and efficacy. Seven patients had an excellent therapeutic response at the end of therapy; however, relapse was noted in 3. When relapse was considered in combination with an initial lack of efficacy, 5 patients (50%; 95% confidence interval, 18.7%-81.3%) did not respond to therapy; these results do not favor the use of azithromycin to treat brucellosis in humans. (+info)
Pilot study of the use of community volunteers to distribute azithromycin for trachoma control in Ghana.
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OBJECTIVE: To assess the skills of community health volunteers in diagnosing active trachoma and distributing azithromycin in the Northern Region of Ghana. METHODS: Six community health volunteers from Daboya were trained to diagnose trachoma and to treat the disease using azithromycin. They were also informed of the drug's possible side-effects. Under supervision, each volunteer then examined, and if necessary treated, 15 households. The dose of azithromycin was determined by weight; height was also measured. Tablets were given in preference to suspension when possible. RESULTS: The volunteers' diagnostic sensitivity for active trachoma was 63%; their specificity was 96%. At the household level, their "decision to treat" was correct in 83% of households. In 344 treatment episodes, volunteers planned a dose of azithromycin outside the range 15-30 mg/kg on only seven occasions (2.0% of all planned treatments). The volunteers' drug management skills were good, the response of the community was excellent, and adverse reactions were infrequent. Diagnosis of active trachoma, record-keeping skills, and knowledge of side-effects were found to need greater emphasis in any future education programme. Most people aged four years or older were able to swallow tablets. For those taking tablets, the correlation between the data gathered for height and weight shows that calculating azithromycin doses by height is a valid alternative to calculating it by weight. CONCLUSION: Trained community health volunteers have a potential role in identifying active trachoma and distributing azithromycin. To simplify training and logistics, it may be better to base dosage schedules on height rather than weight for those taking tablets, which included most people aged four years or more in the population studied. (+info)
Antibiotic treatment in acute Otitis Media promotes superinfection with resistant Streptococcus pneumoniae carried before initiation of treatment.
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Antibiotic-resistant pneumococci are difficult to eradicate from middle ear fluid (MEF) and the nasopharynx (NP). Bacteriologic eradication from the NP and MEF during acute otitis media (AOM) by 3 common antibiotic drugs was prospectively evaluated. In 19 (16%) of 119 MEF culture-positive patients, an organism susceptible to the treatment drug (Haemophilus influenzae, Streptococcus pneumoniae, or both) was isolated from the initial MEF, whereas resistant S. pneumoniae was present in the NP; in 9 (47%) patients, the initial resistant NP organism (identified by serotyping, resistance to the administered drug, and pulsed-field gel electrophoresis) replaced the susceptible MEF organism within only a few days after initiation of treatment. In regions where resistant pneumococci are prevalent, antibiotics may not only fail to eradicate the organisms, but they may often induce MEF superinfection with resistant pneumococci initially carried in the NP. This is an important mechanism by which, in recently treated patients, AOM infections often become refractory to treatment. (+info)