[Anti-anaerobic activity of carbapenems]

The critical concentrations of sensitivity and resistance for meropenem versus anaerobic bacterias were analyzed. It is demonstrated the meropenem is a powerful inhibitor of the microorganisms of the Bacteroides groups (MIC90 < 1 mg/l), Prevotella > Porphyromonas, Fusobacterium, Veillonella, Clostridium perfringens is inhibited at a MIC < 0.06 mg/l. The MIC of meropenem versus C. difficile is 2 mg/l. They are also highly susceptible to the Propionibacterium, Peptostreptococcus and Peptococcus type microorganisms. Meropenem is comparable to imipenem and is more active than piperacillin, metronidazole and clindamycin. The mechanism of action and acquisition of resistance versus meropenem is evaluated and discussed. The percentage of highly resistant strains (MIC > 256 mg/l) isolated in the Hospital Gregorio Marañón in Madrid (Spain) is low (1.2%). The influence of pH on the in vitro activity of the carbapenémicos is also analyzed providing experimental data suggesting that meropenem maintains its bactericide activity more effectively in low pH conditions (5.6). Finally, the authors analyze the literature and the evidence reported regarding the use of meropenem in clinical practice, as a treatment of intraabdominal infections with a clinical response of 91%-100% and bacteriologic efficacy of 84%-95%.