ceftriaxone and Staphylococcal-Infections

Using 98 clinical methicillin-susceptible Staphylococcus aureus isolates of known beta-lactamase (Bla) type, we found a pronounced inoculum effect for cephalexin (mostly Bla type A and C strains), a mild inoculum effect for cephalothin (especially types B and C), and no inoculum effects for ceftriaxone and cefuroxime. Ceftobiprole showed the lowest MICs at a high inoculum but with a slight increase for Bla-positive versus Bla-negative strains. Since a potential therapeutic effect associated with a cephalosporin inoculum effect has been described, further studies are warranted.

Topics: Anti-Bacterial Agents; Ceftriaxone; Cefuroxime; Cephalexin; Cephalosporins; Cephalothin; Humans; Methicillin; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus aureus

AFN-1252, a potent inhibitor of enoyl-acyl carrier protein reductase (FabI), inhibited all clinical isolates of Staphylococcus aureus (n = 502) and Staphylococcus epidermidis (n = 51) tested, including methicillin (meticillin)-resistant isolates, at concentrations of 4 microg/ml) against clinical isolates of Streptococcus pneumoniae, beta-hemolytic streptococci, Enterococcus spp., Enterobacteriaceae, nonfermentative gram-negative bacilli, and Moraxella catarrhalis. These data support the continued development of AFN-1252 for the treatment of patients with resistant staphylococcal infections.

Topics: Anti-Bacterial Agents; Benzofurans; Enoyl-(Acyl-Carrier-Protein) Reductase (NADH); Enterobacteriaceae; Enterococcus; Microbial Sensitivity Tests; Moraxella catarrhalis; Pyrones; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Staphylococcus epidermidis; Streptococcus pneumoniae

Two investigational anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) beta-lactams, ceftaroline (a cephalosporin) and ME1036 (a carbapenem), were subjected to susceptibility testing by reference broth microdilution methods using 152 strains of community-acquired MRSA from the United States (47 medical centers). Ceftaroline and ME1036 were 64- and >128-fold more potent than ceftriaxone, respectively. All isolates had the Panton-Valentine leukocidin genes and staphylococcal cassette chromosome mec type IV, while 67.8% of isolates displayed pulsed-field gel electrophoresis clonal type USA300-0114.

Topics: Anti-Bacterial Agents; beta-Lactams; Carbapenems; Ceftaroline; Cephalosporins; Community-Acquired Infections; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus aureus; United States