A compilation of studies assessing the in vitro activity of meropenem and comparators in 84 laboratories throughout Europe.

OBJECTIVE

To compile the results of investigations conducted in 84 centers throughout Europe of the in vitro activity of meropenem and a standard set of comparators against some 12 000 Gram-positive, Gram-negative, aerobic and anaerobic bacteria.

METHODS

Recent clinical isolates from 84 European countries were tested using Mueller---Hinton broth or agar (aerobes and nutritionally fastidious species) or Wilkins---Chalgren medium (anaerobes) for susceptibility to meropenem, imipenem, cefotaxime, ceftazidime, piperacillin, ciprofloxacin and gentamicin (aerobes) or meropenem, imipenem, clindamycin and metronidazole (anaerobes).

RESULTS

Whether compared across studies or across countries, meropenem and imipenem were the only compounds that produced uniform and predictable activity. The activity of ceftazidime and cefotaxime was compromized because of instability to both chromosomally mediated and new plasmid-mediated (transferable) beta-lactamases. This effect was even more pronounced with piperacillin. Resistance to gentamicin was commonplace, although variable between countries; strains resistant to ciprofloxacin occurred in many genera of Enterobacteriaceae and amongst the pseudomonads. Metronidazole was uniformly active against anaerobes but there were many clindamycin-resistant strains. Resistance, or diminished susceptibility, amongst Streptococcus pneumoniae was found frequently, but of the beta-lactams tested, only ceftazidime and piperacillin produced minimum inhibitory concentration values that could compromize therapeutic efficacy outside the central nervous system.

CONCLUSIONS

These data provide further evidence of the high incidence of antibiotic resistance in Europe, notably in France, Spain and Italy. Fortunately, the carbapenems are highly stable to the enzymes that hydrolyze cephalosporins and penicillins. Hence, they retain an essentially unaltered and exceptional antimicrobial spectrum, embracing the vast majority of strains resistant to the other comparators, although meropenem was more reliable than imipenem against Pseudomonas aeruginosa.