The in-vitro activity of faropenem, a novel oral penem.
The in-vitro activity of faropenem, a novel oral penem, was studied in comparison with other beta-lactam antimicrobials against 711 recent clinical isolates including Gram-negative, Gram-positive and anaerobic bacteria. MIC data showed that faropenem was active against most members of the Enterobacteriaceae (MICs < or = 4 mg/L), with reduced activity against Serratia spp. (MIC90 = 32 mg/L). In common with its comparators, faropenem had weak activity against Pseudomonas aeruginosa and Stenotrophomonas maltophilia (MIC > 128 mg/L). Faropenem was active against staphylococci, although for MRSA MICs were raised (MIC90 = 2 mg/L) compared with those for MSSA (MIC90 = 0.12 mg/L). Faropenem was also found to be active against streptococci, Neisseria spp., Enterococcus faecalis and beta-lactamase-producing and non-producing strains of Haemophilus influenzae and Moraxella catarrhalis. Of the anaerobic bacteria studied, faropenem was most active against peptostreptococci and Clostridium perfringens (MIC90 < or = 1 mg/L) and Bacteroides fragilis (MIC90 = 4 mg/L). An increase in inoculum from 10(4) to 10(6) cfu raised faropenem MICs for Morganella morganii from 0.06-1 mg/L to 2-4 mg/L and for MRSA from 0.25-2 mg/L to 8 mg/L (a similar increase was not observed for MSSA). The MICs of faropenem were not affected by the presence of either 20% or 70% (v/v) serum. MICs for faropenem to 11 well characterized beta-lactamase producers were similar to those of non-producers. In hydrolysis studies, faropenem was shown to be highly stable to a number of beta-lactamases, including TEM-1, SHV-1, the extended spectrum beta-lactamases, TEM-3 and TEM-9, and the beta-lactamase produced by Staphylococcus aureus (NCTC 11561).
Woodcock
J M
JM
Department of Medical Microbiology, City Hospital NHS Trust, Birmingham, UK.
Andrews
J M
JM
Brenwald
N P
NP
Ashby
J P
JP
Wise
R
R
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000201:enzymology; D015780:Carbapenems / Q000378:metabolism / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000201:enzymology; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D006868:Hydrolysis; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism
D000900:Anti-Bacterial Agents; D015780:Carbapenems; C060114:SUN 5555; D001618:beta-Lactamases