Prospective randomized clinical trials of new quinolones versus beta-lactam antibiotics in lower respiratory tract infections.

In four prospective randomized clinical trials between November 1983 and March 1988, we studied 270 patients with severe bacterial infections, mainly lower respiratory tract ones. We compared ciprofloxacin and imipenem/cilastatin in the first study, ciprofloxacin and ofloxacin in the second study, ciprofloxacin and ticarcillin/clavulanic acid in the third study, and ofloxacin and cefpirome in the fourth study. A total of 90 pneumonias, 139 LRTIs, 22 septicaemias and 19 other bacterial infections were treated; the dominant pathogens were Pseudomonas aeruginosa and enterobacteria. Clinical success rates were high; cure or improvement was registered in 89% of the patients on ciprofloxacin, 89% on ofloxacin and 85% on beta-lactams. Treatment failures occurred mainly in ICU patients with terminal underlying diseases. Bacteriologically, eradication rates were high for enterobacteria and Staphylococcus aureus, but a relatively high persistence rate was seen for P. aeruginosa due to increased resistance and/or specific type and location of the infections. The incidence of side-effects was relatively high (23%-29%) which was related to careful monitoring. Adverse effects were group-specific (CNS reactions with quinolones, diarrhoea with beta-lactam antibiotics).