Microbiological and pharmacokinetic evaluation of cefonicid, a long-acting cephalosporin.

The in vitro antimicrobial activity of cefonicid has been tested against 27 recent clinical isolates of 7 different species (S. aureus, E. coli, K. pneumoniae, P. mirabilis, S. marcescens, E. cloacae and P. aeruginosa) using the MS-2 Research System, contrast phase microscopy and the colony forming unit assay. With the exception of P. aeruginosa, S. marcescens and E. cloacae, cefonicid showed excellent activity against the different bacterial species tested (i.e. S. aureus, E. coli, K. pneumoniae and P. mirabilis). Tissue penetration of cefonicid after a single i.m. or i.v. dose (1 or 2 g, respectively) was also studied using the suction blister method. In 14 adult subjects with normal renal and liver functions, cefonicid plasma half-life was 5.1 and 5.4 h following i.v. and i.m. administration. Drug concentrations achieved at peak in plasma and suction blister fluid were higher than the minimum inhibitory concentrations for most sensitive pathogens and remained above these values for 24 h. These data support the use of a single daily dose regimen of cefonicid, both i.v. and i.m., for the treatment of most common infections caused by sensitive pathogens in blood and tissues.