Synergy of mecillinam and clavulanic acid with other beta-lactam antibiotics

Enhanced activity of beta-lactam antibiotics with amdinocillin in vitro and and in vivo

An important advantage of antibiotic combinations which can be determined is the increase in spectrum of activity. Ad hoc combinations of amdinocillin with ampicillin, ticarcillin, piperacillin, azlocillin, cefazolin, cefamandole, cefoxitin, and moxalactam in ratios similar to those in serum after parenteral administration of normal dosages of these agents were tested in vitro against over 200 strains of bacteria, including Staphylococcus aureus, Streptococcus faecalis, representative genera of the Enterobacteriaceae, and Pseudomonas aeruginosa. Independent of amdinocillin's activity, it was possible to show marked enhancement of the spectrum of all the beta-lactam agents tested, except moxalactam, against members of the Enterobacteriaceae. Little or no enhancement or antagonism of activity was seen against gram-positive bacteria or P. aeruginosa. The enhancing activity of amdinocillin on three beta-lactam antibiotics, ampicillin, cefazolin, and cefoxitin, was also demonstrated in experimental mouse infections with gram-negative bacteria.

A combination of amoxicillin and clavulanic acid in the treatment of respiratory tract infections caused by amoxicillin-resistant haemophilus influenzae

This study was undertaken to evaluate the efficacy of a fixed combination of amoxicillin and clavulanic acid in 33 patients with chronic or recurrent respiratory tract infections (R.T.I.), mainly bronchitis. In two patients bronchopneumonia was diagnosed, and in one cystic fibrosis. The patients were treated with 750 mg of the drug combination (500 mg amoxicillin/250 mg clavulanic acid) t. i. d. for seven or ten days. Good clinical success was obtained in 17 patients and a clear improvement in another eight. The most frequently isolated micro-organism was Haemophilus influenzae; of the 22 strains isolated, 20 were resistant to 2 mg/l amoxicillin but sensitive to the combination of 2 mg/l amoxicillin and 1 mg/l clavulanic acid. Side-effects were reported in nine patients; two patients discontinued treatment for this reason. Amoxicillin/clavulanic acid is a useful therapeutic addition to the existing forms of treatment for amoxicillin-resistant respiratory tract infections.