carumonam and Cross-Infection

In vitro activity of a new monobactam, carumonam (RO 17-2301, AMA 1080) was tested against 370 hospital bacterial isolates. Results were compared to aztreonam, cefotaxime, cefmenoxime, latamoxef, ceftazidime, ceftriaxone, pefloxacin against Enterobacteriaceae, to aztreonam, piperacillin, cefoperazone, cefsulodin, ceftazidime, imipenem and pefloxacin against P. aeruginosa. All Enterobacteriaceae strains produced cephalosporinases and all P. aeruginosa strains were ticarcillin resistant. MIC 90% of carumonam against Enterobacteriaceae strains was lower than 0.25 mg/l for P. mirabilis, P. vulgaris, P. stuartii, Salmonella sp., ranged from 0.25 to 0.5 mg/l for Klebsiella sp. and S. marcescens, from 1 to 2 mg/l for E. coli and P. morganii, and from 4 to 8 mg/l for C. freundii and E. cloacae. The rate of strains inhibited with 4 mg/l of carumonam was 95.3%. So carumonam was at the second place from eight tested products, after latamoxef (97.5% of susceptible strains). Carumonam was active against second generation cephalosporins resistant strains when these strains were susceptible or intermediate to cefotaxime. Strains resistant to this compound escaped to its action. Its activity against A. calcoaceticus was weak (22.6% of strains inhibited by 4 mg/l), but was superior to that of cefsulodin against ticarcillin resistant P. aeruginosa strains (54.5 versus 16.1% of susceptible strains). However carumonam was less active against this last species than ceftazidime or imipenem (92.6 and 91% of susceptible strains respectively).

Topics: Anti-Bacterial Agents; Aztreonam; beta-Lactams; Cross Infection; Gram-Negative Bacteria; Humans; Microbial Sensitivity Tests

Minimal inhibitory concentrations (MICs) of carumonam (RO 17-2301), a new synthetic antibacterial agent of the monobactam group, were evaluated by agar dilution for 399 hospital isolates. RO 17-2301 was inactive against Gram positive and anaerobic bacteria. Most Enterobacteriaceae were inhibited by concentrations less than 1 microgram/ml, with mode MICs approximating 0.03 micrograms/ml except for Providencia (0.016), Citrobacter (0.06), Serratia (0.06) and Enterobacter (0.12). A few strains, most of which were Enterobacter or Citrobacter, had high MICs (greater than 8 micrograms/ml). RO 17-2301 was less active against Pseudomonas aeruginosa (mode MIC 2 micrograms/ml) and Acinetobacter (mode MIC 8-16 micrograms/ml). Haemophilus influenzae sp. were sensitive to RO 17-2301 (mode MIC 0.12-0.25), regardless of beta-lactamase production status; MICs ranged from 0.06 to 0.25 micrograms/ml for Meningococci, and from 0.008 to 0.06 for Gonococci except for a few strains that had higher MICs (0.25 to 0.5 and even 4 micrograms/ml). In vitro activity of RO 17-2301 on Gram negative bacteria proved similar to that of third-generation cephalosporins; cefotaxime-resistant Enterobacteriaceae are resistant to RO 17-2301.

Topics: Anti-Bacterial Agents; Aztreonam; Bacteria; Cross Infection; Humans; Lactams; Microbial Sensitivity Tests