Pivmecillinam in the treatment of therapy resistant urinary tract infections. A comparison with pivmecillinam, pivampicillin and their combination

Abstract

Pivmecillinam is a new penicillin-like compound belonging to the so-called amidinopenicillins and characterized by a high antibacterial activity against Enterobacteriaceae and by demonstrated synergism when combined with other beta-lactam antibiotics. In this prospective trial geriatric patients with a stationary indwelling catheter and significant bacteriuria caused by Enterobacteriaceae were treated for four weeks with pivmecillinam, pivampicillin or various combinations of the two compounds. Urine specimens were obtained weekly, and in eight patients receiving pivmecillinam 75% of the urine samples were free from Enterobacteriaceae during the period of treatment. The figure was 91% in 24 patients receiving combination therapy. In seven patients treated with an equimolar dose of pivampicillin alone 43% and 23% of the urine specimens, controlled during the first and the second havles of the treatment period respectively, Enterbacteriaceae was eradicated. In this group there was a marked and increasing tendency towards infections caused by more resistant strains of Enterobacteriaceae as the treatment progressed. The latter is keeping with the observation that pivmecillinam, as opposed to ampicillin, apparently does not cause any selection of resistant Enterobacteriaceae in the faecal flora which is the main source of urinary pathogens.