Sch 29482--a novel penem antibiotic: an in-vitro comparison of its activity with other -lactams

Abstract

Sch 29482 (SCH) is a penem antibiotic and its in-vitro activity was compared with other β -lactams including N-formimidoyl-thienamycin (MK 0787) and the novel monobactam SQ 26776 (azthreonam). SCH and MK 0787 had similar high activities against the Enterobacteriaceae (M1C ₉₀ 0.5−2mg/l). MK 0787 and SQ 26776 were active against Pseudomonas aeruginosa (M1C ₉₀ 2 and 8 mg/l, respectively) but SCH was inactive. All three agents were highly active against Haemophilus influenzae and Neisseria gonorrhoeae . SCH, like MK 0787 included Staphylococcus aureus within its spectrum of activity but SQ 26776 was inactive. SCH was also active against characterized β -lactamase producing bacteria. The MBCs of SCH were twice the MICs and in the presence of 75% serum the MIC and MBC of SCH increased 8– to 16–fold. SCH is stable in serum at −20°C but loses activity at 6% per hour at 37°C. The serum protein binding of SCH was approximately 95%.