Comparative in-vitro activity of the penem FCE 22101 against recent European blood culture isolates.
Recent blood culture isolates (462 strains of Gram-negative bacilli and 288 strains of staphylococci) collected in 30 European laboratories were tested for susceptibility to five beta-lactam antibiotics by a microdilution method in Mueller-Hinton broth. The penem FCE 22101 and imipenem were very active against the Gram-negative bacilli, except the pseudomonads, FCE 22101 being four- to 16-fold less active (MIC50 2 mg/l; MIC90 8 mg/l) than imipenem MIC50 0.5 mg/l; MIC90 2 mg/l). Ceftibuten and ceftazidime were also active (MIC50 0.25 mg/l; MIC90 greater than 16 mg/l). The MIC of piperacillin (MIC50 8 mg/l; MIC90 greater than 64 mg/l) were two- to 16-fold reduced in the presence of the beta-lactamase inhibitor YTR-830 against these bacteria. Only imipenem and piperacillin inhibited the pseudomonads (MIC50 4 and 8 mg/l respectively; MIC90 16 mg/l and greater than 64 mg/l), with two-fold reduction in MIC50 of piperacillin in the presence of YTR-830. The staphylococci were very susceptible to FCE 22101 and imipenem (MIC50 less than or equal to 0.25 mg/l) except some cefazolin-resistant strains. In Staphylococcus aureus penem resistance was better expressed after bacterial growth at 30 degrees C. Some strains of Staph. epidermidis were susceptible to FCE 22101 but resistant to imipenem. The cephalosporins were not active against the staphylococci, and the presence of YTR-830 caused a four- to 16-fold reduction in MIC of piperacillin.
Dornbusch
K
K
Department of Clinical Microbiology, Karolinska Hospital, Stockholm, Sweden.
Kronvall
G
G
Göransson
E
E
Mörtsell
E
E
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D015780:Carbapenems; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006801:Humans; D008712:Methicillin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D011549:Pseudomonas / Q000187:drug effects; D018805:Sepsis / Q000382:microbiology*; D013210:Staphylococcus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D015780:Carbapenems; C040033:ritipenem; D008712:Methicillin