Comparative efficacy of 5 days of dirithromycin and 7 days of erythromycin in skin and soft tissue infections.

We investigated the comparative efficacy and safety of dirithromycin and erythromycin in the treatment of skin and soft tissue infections in this double-blind, randomized, multicentre study, in which 439 patients were randomized to treatment with dirithromycin (500 mg daily for 5 days) or erythromycin (250 mg every 6 h for 7 days). All randomized patients were included in the termination analysis, which showed that 187 of 220 (85.0%) dirithromycin recipients and 177 of 219 (80.8%) erythromycin recipients were clinically cured or improved (95% confidence interval (CI) -3.0% to +11.4%). In the termination analysis of the 211 bacteriologically evaluable patients, clinical cure or improvement occurred in 83 of 100 (83%) dirithromycin recipients and in 89 of 111 (80.2%) erythromycin recipients (95% CI -7.8% to +13.4%), and bacteriological eradication occurred in 85 of 100 (85%) and 89 of 111 (80.2%), respectively. Adverse events were similar in incidence and nature between the two groups, except that there was less nausea with dirithromycin (3.6% versus 8.2%; P = 0.042). Ten of 220 (4.5%) dirithromycin recipients and 27 of 219 (12.3%) erythromycin recipients returned >20% of their prescribed medication (P = 0.033). In the treatment of skin and soft tissue infections, dirithromycin (500 mg daily for 5 days) was comparable in efficacy to, and caused significantly less nausea than, erythromycin (250 mg every 6 h for 7 days). Compliance with the dirithromycin regimen was superior to that with the erythromycin regimen.

Five-day dirithromycin therapy is as effective as seven-day erythromycin therapy for acute exacerbations of chronic bronchitis.

In a meta-analysis of two identically designed, well-controlled, randomized, double-blind clinical trials, we compared 5 days of dirithromycin with 7 days of erythromycin for acute exacerbations of chronic bronchitis. Five hundred and thirty-one patients were randomized to receive dirithromycin (500 mg od) for 5 days and 526 patients were randomized to receive erythromycin (250 mg qid) for 7 days. Clinical and bacteriological responses were assessed 3-5 days after therapy and at termination from the study. Adverse events were collected from both groups and compared with each other, before and after treatment. Of the 690 patients clinically appraisable at the post-therapy visit, 298 (84.2%) dirithromycin-treated patients and 270 (80.4%) erythromycin-treated patients showed a favourable response. At termination, 273 (77.1%) dirithromycin-treated patients and 243 (72.3%) erythromycin-treated patients showed a favourable response. The microbiological cure was equivalent in the two groups (75% of dirithromycin-treated patients and 74.1% of erythromycin-treated patients showed a favourable response at termination). After therapy, dirithromycin was as effective as erythromycin in eradicating Streptococcus pneumoniae (77.8% vs 90.9%), Haemophilus influenzae (71.7% vs 72.2%), Moraxella catarrhalis (93.3% vs 88.9%) and Staphylococcus aureus (81.8% vs 82.1%). Although not statistically significant, fewer dirithromycin-treated patients reported adverse events than did erythromycin-treated patients. Nausea (6.8% vs 7.8%), headache (7.3% vs 8.2%) and diarrhoea (6.6% vs 9.5%) were the most frequently reported adverse events in both groups. In the treatment of acute exacerbations of chronic bronchitis, 5 days of dirithromycin is as effective as 7 days of erythromycin.

Daptomycin: a novel agent for Gram-positive infections.

The alarming increase in the incidence of Gram-positive infections, including those caused by resistant bacteria, has sparked renewed interest in novel antibiotics. One such agent is daptomycin, a novel lipopeptide antibiotic with proven bactericidal activity in vitro against all clinically relevant Gram-positive bacteria. These include resistant pathogens, such as vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), glycopeptide intermediately susceptible Staphylococcus aureus (GISA), coagulase-negative staphylococci (CNS) and penicillin-resistant Streptococcus pneumoniae (PRSP), for which there are very few therapeutic alternatives. Daptomycin provides rapid, concentration-dependent killing and a relatively prolonged concentration-dependent post-antibiotic effect in vitro. Spontaneous acquisition of resistance to daptomycin occurs rarely. Daptomycin exhibits linear pharmacokinetics, minimal accumulation with once-daily dosing, and low plasma clearance and volume of distribution. Phase II clinical trials indicate that daptomycin at doses of 2 mg/kg q24 h and 3 mg/kg q12 h is efficacious against skin and soft tissue infections and bacteremia, respectively. In addition, results in endocarditis suggested potential efficacy with higher doses. On the basis of clinical trials to date, it appears that daptomycin has an excellent safety profile, with the incidence and nature of serious adverse events comparable to those observed with conventional therapy. Adverse events associated with other classes of antimicrobials (nephrotoxicity, local irritation, ototoxicity, hypersensitivity, and gastrointestinal effects) were uncommon with daptomycin. Minimal skeletal muscle toxicity was seen at only the highest dose tested (4 mg/kg q12 h), predicted by elevations in serum creatinine phosphokinase, and readily reversible upon discontinuation of treatment. There were no signs of toxicity in cardiac or smooth muscle. Phase II and III clinical trials are underway to evaluate daptomycin for the treatment of Gram-positive bacteremia and complicated skin and soft tissue infections, respectively. Daptomycin holds promise as a rapidly acting and highly effective antibiotic for Gram-positive infections.

Cysteine protease inhibitors block schistosome hemoglobin degradation in vitro and decrease worm burden and egg production in vivo.

Schistosome parasites utilize hemoglobin as a major protein source for their metabolism. Degradation of hemoglobin has been hypothesized to be mediated by both cysteine and aspartyl proteases secreted into the lumen of the parasite intestine. We now show that two distinct types of irreversible cysteine protease-specific inhibitors both arrest schistosome hemoglobin degradation in vitro. Arrest of hemoglobin degradation is followed by death of developing schistosomula 1 week later. Schistosome infected mice treated by a dose of 2 mg inhibitor per day for 1 week early in infection, and 2 weeks at the time of egg production, showed a significant reduction in worm burden, hepatomegaly, and the number of eggs produced per female worm. Histopathology showed a minimal immune response to those eggs which were produced, consistent with a delay in egg production relative to untreated infections. By tagging the inhibitor with biotin, specific cysteine protease targets were identified in extracts of schistosome worms.