Antibacterial properties of imipenem with special reference to the activity against methicillin-resistant staphylococci, cefotaxime-resistant Enterobacteriaceae and Pseudomonas aeruginosa

Abstract

Imipenem was examined with standardized agar dilution procedures against a wide range of bacteria. Geometric mean MICs against the genera Escherichia, Klebsiella, Enterobacter, Citrobacter and Serratia were 0.1-0.4 mg/l, and Proteus and Providencia spp. were inhibited by 0.25-4 mg/l. Acinetobacter calcoaceticus var. anitratum strains were inhibited by concentrations ranging from 0.12-0.5 mg/l. Methicillin-susceptible staphylococci were highly susceptible to the drug (MICs: less than or equal to 0.03 mg/l) and enterococci were inhibited by 0.25-16 mg/l. Most of the multi-resistant JK corynebacteria were resistant to imipenem. Imipenem was more active than any other beta-lactam against methicillin-resistant staphylococci; this was also demonstrated in a population analysis. Imipenem-resistant minorities in populations, however, were also observed. Cefotaxime-resistant and -intermediate Enterobacter and Citrobacter strains were inhibited by concentrations of 0.5 mg/l or less. No third-generation cephalosporin nor any other beta-lactam showed similarly high activity against these groups of organisms. Among 20 ceftazidime-resistant and 20 ceftazidime-susceptible isolates of Pseudomonas aeruginosa, no strain was resistant and only five ceftazidime-resistant strains were intermediately susceptible (MIC, 8 mg/l) to imipenem.

Comparison of Imipenem and Five Other Antipseudomonal Agents against Gentamicin-Susceptible and -Resistant <i>Pseudomonas aeruginosa</i>

“…Several investigators have shown that imipenem possesses an activity superior to previous (3-lactams against P. aeruginosa, in cluding strains resistant to third-generation ce phalosporins [4,5]. The narrow range of the MICs of imipenem against our P. aeruginosa strains is comparable to that reported by other investigators.…”

Comparative Antibacterial Activity of the Penem ALP 201

“…1) is a recent penem anti biotic available for intravenous adminis tration [1,2], The objective of the present study is to compare the activity of ALP 201 with other relevant antibacterial com pounds against gram-negative rods and gram-positive cocci [3,4], C 0 2Na , USA.…”