Intravenous meropenem versus imipenem/cilastatin in the treatment of serious bacterial infections in hospitalized patients. Meropenem Serious Infection Study Group.

Meropenem was compared with imipenem/cilastatin for the treatment of serious bacterial infections in a randomized, prospective multicentre study. Both study drugs were given intravenously 1 g every 8 h and no other antimicrobial agents were permitted concomitantly. Of the 204 patients enrolled, the treatment of 177 was evaluable for clinical efficacy and 115 for bacteriological efficacy. In the clinically evaluable treatment population, 75 (83%) of the 90 patients in the meropenem group and 78 (90%) of the 87 in the imipenem/cilastatin group had a single site of infection whereas the remainder had two or more sites of infection. Infections of the lower respiratory tract and peritoneal cavity predominated accounting for 95 and 75 cases respectively. Other infections included skin and soft tissue infections, complicated urinary tract infections, bacteraemia and a case of meningitis treated with meropenem and one of mediastinitis treated with imipenem/cilastatin. One hundred and nineteen (67%) patients were in an intensive care unit, 105 (59%) were receiving assisted ventilation and 93 (53%) of the patients had failed previous antibiotic therapy. One hundred and ten organisms were identified as pathogens in the meropenem group and 109 in the imipenem/cilastatin group. Overall, treatment with meropenem was clinically successful in 68 (76%) of 90 cases and imipenem/cilastatin in 67 (77%) of 87 cases and the corresponding eradication rates of bacteria were 85 of 110 (77%) and 90 of 109 (83%) respectively. Superinfections due to resistant bacteria occurred in two patients treated with meropenem and three cases given imipenem/cilastatin. No statistically significant differences in the clinical or bacteriological outcome were observed between the treatment groups for any of the infection sites analysed. Both drugs were well tolerated with adverse events considered to be related to therapy being recorded for 10 (9%) of 106 patients treated with meropenem and 12 (12%) of 98 of those who had been given imipenem/cilastatin. Empirical monotherapy with meropenem was therefore as effective and as well tolerated as that with imipenem/cilastatin for the treatment of serious bacterial infections.