A study of the clinical effects of clindamycin on respiratory infections -Focusing on inhibition of β-lactamase production-

The efficacy and safety of injectable clindamycin-2-phosphate (CLDM) and a β-lactam antibiotic in combination were assessed at 25 institutions in Japan, focusing especially on CLDM's inhibitory effect on the production of β-lactamase. A total of 31 cases were included in the study. There were 4 cases the responded well to the β-lactam antibiotic alone and the one case also treated with a steroid. The other 26 cases consisted of 10 cases of chronic bronchitis, 8 of bronchiectasis, 1 of diffuse panbronchiolitis, 6 of pneumonia, and 1 of lung abscess. The medication was started with intravenous drip infusion of a recommended dose of β-lactam antibiotic divided in two doses, and when the drug did not show efficacy by treatment day 3, 1, 200-2, 400 mg/day of CLDM in two equal doses was added starting on day 4. CLDM was given generally up to day 7, but up to day 10 in some cases, to assess the efficacy of combination therapy. Final clinical efficacy was good in 90.0% (9/ 10) of the cases of chronic bronchitis, 71.4% (5/7) of the cases of bronchiectasis, 100% (1/1) of the cases of diffuse panbronchiolitis, and 100% (5/5) of the cases of pneumonia, but poor in the single case of lung abscess. Sputum β-lactamase activity had decreased by day 4 of combination therapy in all cases which had shown low or moderate (<500 μU/ml) β-lactamase activity before the addition of CLDM. In 8 of the 9 patients with high β-lactamase activity (>500 μU/ml), it started to tend to decline on day 1 of combination therapy. Clinical efficacy and β-lactamase activity were correlated: r=0.665 (p<0.01) in the high β-lactamase activity group and r=0.666 (p<0.01) in the low/moderate activity group. Side effects wer noted in 2 of the 31 cases, but both were mild and allowed continued treatment. A slight rise in S-GOT was detected in one case, but it returned to normal after the completion of therapy. These findings suggest the clinical usefulness of combination therapy with CLDM and a β-lactam antibiotic, partly due to CLDM's inhibitory effect on the production of β-lactamase.