The therapeutic effects of cyclacillin in acute sinusitis:in vitroandin vivocorrelations in a placebo-controlled study

Abstract

In 50 adults with bacterial sinusitis, cyclacillin (1500 mg. per day for 7 days) proved significantly more effective than placebo in eliminating the signs and symptoms and in eradicating the causative microorganisms, (Staphylococcus aureus, Proteus mirabilis, and Staph, epidermidis were most frequently isolated in this series). Sixty percent of the cultures in the cyclacillin series were sterilized, compared with only 10% in the placebo series. Globally, 93% of the cyclacillin-treated patients and only 55 % of the placebo-treated patients were considered improved. Of the P. mirabilis strains encountered, 72% were eradicated by cyclacillin (only 40% by placebo) despite the relatively high cyclacillin M.I.C.s for this microorganism (50 to 100 μg/ml.). Cyclacillin was much more effective in treating human sinusitis than would have been anticipated from the M.I.C.s alone.