Mecillinam in urinary tract infections and in septicaemia.

The clinical and bacteriological efficacy as well as the tolerance of mecillinam, a new beta-lactam antibiotic, administered parenterally in a dose of 40 mg/kg body weight, was investigated in 21 hospitalized patients with urinary tract infections or septicaemia. Success, defined as eradication of infecting organisms two to five days after treatment, was found in eight of 16 patients with urinary tract infections. Persistence of the original pathogen after treatment was seen in four patients, all with complicated urinary tract infection. Reinfection was seen in two patients, while the results were unevaluable in two cases. The five patients with septicaemia were all cured of their infection, this result being attributed solely to mecillinam in two cases, while a combined action of mecillinam and another antibiotic produced a cure in the other three cases. Escherichia coli resistant to mecillinam were isolated from two patients with persistence of bacteriuria following mecillinam treatment. Impairment of renal function may have been a contributory factor to the poor treatment response in patients with complicated urinary tract infection. Inasmuch as no important side-effects were recorded and mecillinam appears safe in patients with impaired renal and liver function, a higher dose may be indicated in these more complicated cases.