An effective antibiotic cover for the prevention of endocarditis following dental and other post-operative bacteraemias.

Pre- and post-extraction blood cultures were taken from 242 patients. The post-extraction ones were taken from 100 unpremedicated patients, from 42 with an erythromycin estolate cover, and from 100 patients after protection with pyrrolidino methyl tetracycline. The 100 post-extraction blood cultures from unpremedicated patients gave 64 positive results which yielded 155 strains, 88 of which were not aerobes. One hundred and fifteen representative strains were tested for sensitivity to 22 antibiotics. Of the 42 patients who received the erythromycin orally, 16 yielded positive blood cultures of mixtures of aerobes and anaerobes and of the 100 given one intravenous injection of the tetracycline three only developed a bacteraemia of a single type of aerobe. The serum concentrations obtained with the tetracycline given intravenously were 15 to 20 times higher than the serum levels obtained with the erythromycin given orally. There is a strong indication for using this kind of efficient antibiotic cover for dental extractions and other operative procedures known to be followed by a bacteraemia.