meropenem and trovafloxacin

Three broad-spectrum antibiotics are reviewed, each from a different class. Meropenem is closely related to imipenem and was recently approved for use in children. Its advantages over imipenem include greater activity against gram-negative bacteria and lack of association with seizures. Cefepime is a fourth generation cephalosporin with the gram-positive activity of cefotaxime and the gram-negative spectrum of ceftazidime. Trovafloxacin is a fluoroquinolone with an exceptionally broad antibacterial spectrum. Meropenem is approved for use in children, cefepime is approved for use in adults only, and trovafloxacin is still undergoing clinical trials. These agents should be reserved for treatment of serious infections, especially those in immunocompromised patients or polymicrobial infections.

Topics: Anti-Infective Agents; Cefepime; Cephalosporins; Child; Fluoroquinolones; Humans; Meningitis, Bacterial; Meropenem; Naphthyridines; Thienamycins

Acinetobacter baumannii is an opportunistic pathogen associated with numerous nosocomial infections. In recent years it has shown extraordinary ease in developing resistance to most antimicrobial agents, which is a serious problem as it makes these infections difficult to treat. We determined the in vitro activity of eight quinolones, five betalactam agents and colistin in 160 clinical isolates of A. baumannii. In general, we observed a high rate of resistance to the quinolones (90%), excluding clinafloxacin (25%), and to ampicillin-sulbactam (61.25%) and imipenem (50%). Colistin is the agent with least resistance (13.125%), although its toxicity limits its therapeutic use. Clinafloxacin may be a good option to treat A. baumannii infections, especially in cases of therapeutic failure with other antimicrobial agents.

Topics: Acinetobacter; Acinetobacter Infections; Ampicillin; Anti-Infective Agents; Aza Compounds; Cefepime; Cephalosporins; Ciprofloxacin; Colistin; Fluoroquinolones; Gatifloxacin; Humans; Imipenem; Meropenem; Microbial Sensitivity Tests; Moxifloxacin; Nalidixic Acid; Naphthyridines; Norfloxacin; Ofloxacin; Opportunistic Infections; Quinolines; Sulbactam; Thienamycins

We studied the effect of pH (7.1, 6.3, and 5.8) on the in vitro susceptibilities of 59 isolates of Bacteroides fragilis and 60 isolates of other B. fragilis group species to trovafloxacin, ciprofloxacin, clindamycin, ampicillin-sulbactam, piperacillin-tazobactam, imipenem, and meropenem. For each agent tested the geometric mean MIC was highest at pH 5.8, intermediate at pH 6.3, and lowest at pH 7.1. The magnitude of the pH effect varied greatly among different antibiotics. These data show that an acidic pH decreases the in vitro susceptibilities of the B. fragilis group to several antibiotics.

Topics: Ampicillin; Anti-Bacterial Agents; Anti-Infective Agents; Bacteroides fragilis; Ciprofloxacin; Clindamycin; Drug Therapy, Combination; Fluoroquinolones; Hydrogen-Ion Concentration; Imipenem; Meropenem; Microbial Sensitivity Tests; Naphthyridines; Penicillanic Acid; Piperacillin; Piperacillin, Tazobactam Drug Combination; Sulbactam; Thienamycins

The in vitro activity of trovafloxacin alone and in combination with ceftazidime, meropenem, and amikacin was studied by determining the minimal inhibitory concentrations (MICs) for 111 gram-negative and 71 gram-positive bacteria. In addition, the synergy of these combinations against 46 strains of gram-negative and gram-positive organisms was studied by checkerboard titration and time-kill kinetics. Trovafloxacin exhibited excellent in vitro activity against all strains tested. Synergism was observed in 17% of the gram-negative strains and in 32% of the gram-positive strains. No antagonism was observed with any of the combinations tested.

Topics: Amikacin; Anti-Infective Agents; Bacteria; Ceftazidime; Drug Therapy, Combination; Fluoroquinolones; Humans; Meropenem; Microbial Sensitivity Tests; Naphthyridines; Thienamycins