The antibacterial effect of antibiotics in treatment of maxillary sinusitis.

The antibacterial effect of antibiotic treatment in maxillary sinusitis has been assessed by studying the elimination of bacteria from the maxillary sinus during treatment with penicillin and tetracycline. As adequate antibiotic concentrations are the prerequisite for maximal antibacterial effect, the antibiotic concentrations were controlled. The antibiotic concentrations were determined in maxillary sinus secretions and/or mucosas of 113 patients with maxillary sinusitis, treated with single or repeated doses of penicillin or tetracycline, or the two antibiotics in combination. In 30 patients treated with either penicillin or tetracycline, the bacterial growth in sinus secretion was controlled before and after treatment. It was established that ordinary clinical doses of penicillin and tetracycline may, although not invariably, result in antibiotic concentrations in sinus secretion and sinus mucosa than can be regarded as adequate for treatment, i.e. for penicillin greater than or equal to 0.25 mug/ml and for tetracycline greater than or equal to 1.0 mug/ml. The necessity of achieving adequate antibiotic concentrations in sinus secretion and sinus mucosa to ensure therapeutic success was demonstrated. Thus, bacterial growth remained in the secretions of most maxillary sinuses when the concentrations of penicillin or tetracycline in the secretions were not regarded as adequate for treatment. In contrast, the bacteria were exterminated in most cases where concentrations were regarded as adequate.