In vitro activities of the novel cephalosporin LB 11058 against multidrug-resistant Staphylococci and Streptococci.

LB 11058 is a novel parenteral cephalosporin with a C-3 pyrimidinyl-substituted vinyl sulfide group and a C-7 2-amino-5-chloro-1,3-thiazole group. This study evaluated the in vitro activity and spectrum of LB 11058 against 1,245 recent clinical isolates, including a subset of gram-positive strains with specific resistant phenotypes. LB 11058 was very active against Streptococcus pneumoniae. The novel cephalosporin was 8- to 16-fold more potent than ceftriaxone, cefepime, or amoxicillin-clavulanate against both penicillin-intermediate and -resistant S. pneumoniae. LB 11058 was also very active against both beta-hemolytic streptococci (MIC at which 90% of isolates were inhibited [MIC(90)], 64 micro g/ml) and Corynebacterium spp. (MIC(50), 32 micro g/ml). Against gram-negative pathogens, LB 11058 showed activity against Haemophilus influenzae (MIC(90), 0.25 to 0.5 micro g/ml) and Moraxella catarrhalis (MIC(90), 0.25 micro g/ml), with MICs not influenced by beta-lactamase production. In conclusion, LB 11058 demonstrated a broad antibacterial spectrum and was highly active against gram-positive bacteria, particularly against multidrug-resistant staphylococci and streptococci.