In vitro activity of meropenem against organisms causing serious infections in a Singapore hospital

Widespread resistance to new antimicrobials in a university hospital before clinical use

The activity of cefpirome, cefepime and piperacillin/tazobactam previously unused in the hospital was evaluated in parallel with five broad-spectrum antibiotics (ceftazidime, ceftriaxone, imipenem, ciprofloxacin and amikacin) currently being used to treat serious infections in the National University Hospital, Singapore. Two hundred and two clinically significant, organisms consecutively isolated during 1998 were included in the study. In vitro efficacy of cefepime, cefpirome and piperacillin/tazobactam was not superior to imipenem, ciprofloxacin and amikacin which are currently used. More than 40% of Enterbacteriaceae were found to be ESBL producers. The incidence of nosocomial organisms resistant to drugs used in serious infections had increased since 1995. Imipenem-resistance occurred in 34.4% of Acinetobacter spp. and 19.2% Pseudomonas aeruginosa. No single agent appeared to be suitable for empirical monotherapy of serious sepsis.

Meropenem: a review of its use in patients in intensive care

Meropenem is a carbapenem antibacterial agent that has antimicrobial activity against gram-negative, gram-positive and anaerobic micro-organisms. In vitro studies involving isolates from patients in intensive care units (ICUs) indicate that meropenem is more active against most gram-negative pathogens than other comparators (including imipenem), although, compared with imipenem, meropenem is less active against most gram-positive organisms. Resistance to meropenem is uncommon in most bacteria. Treatment with meropenem as initial empirical monotherapy was effective in a range of serious infections in adult and paediatric ICU patients. Meropenem monotherapy was as effective as imipenem/cilastatin in 4 comparative trials in terms of satisfactory clinical and bacteriological responses. Meropenem monotherapy was significantly more effective than ceftazidime-based combination treatments in 2 trials in patients with nosocomial lower respiratory tract infections (LRTIs) in terms of both clinical and bacteriological responses. Meropenem was also more active than ceftazidime-based treatments against both gram-positive and gram-negative organisms. However, 2 studies in patients with a range of serious infections found no significant differences between meropenem and cephalosporin-based treatments in terms of clinical or bacteriological response. Meropenem was also as effective as cephalosporin-based treatments in comparative trials in children with serious infections. Meropenem is well tolerated as either a bolus or an infusion, and clinical trials have shown similar incidences of adverse events to those observed with cephalosporin-based treatments. It is well tolerated by the CNS, with seizures reported infrequently, and can therefore be used at high doses and in patients with meningitis. The incidence of drug-related nausea and vomiting is low and, in contrast to imipenem/cilastatin, does not increase with dose or speed of administration.

CONCLUSIONS

Meropenem is a well tolerated broad spectrum antibacterial agent that, when used as initial empirical monotherapy, is as effective as imipenem/cilastatin in the treatment of a range of serious infections (including nosocomial) in adults and children in ICUs. Compared with cephalosporin-based combination treatments, meropenem monotherapy may be more effective in the treatment of nosocomial LRTIs and can be used as monotherapy. Meropenem has an important role in the empirical treatment of serious infections in adults and children in ICUs.