LB 11058 is a novel injectable cephalosporin featuring a C-3 pyridyl-substituted vinyl sulfide and a C-7 2-amino-5-chloro-1,3-thiazole group. This compound exhibits exceptional activity against Streptococcus pneumoniae and demonstrates similar efficacy against β-hemolytic streptococci. The inhibition pattern for LB 11058 with S. aureus is consistent, as all isolates are inhibited under this pattern.