Anti-pseudomonal activity of HR 810.

The anti-pseudomonal activity of HR 810, a new 2-aminothiazolyl cephalosporin, was compared to that of carbenicillin, azlocillin and cefsulodin against 187 non-fermenters. HR 810 was the best agent against Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas fluorescens and Acinetobacter calcoaceticus with an MIC50 less than or equal to 4 mg/l and an MIC90 less than or equal to 16 mg/l. It was as effective as azlocillin against Pseudomonas stutzeri and Pseudomonas mendocina, with an MIC50 less than or equal to 0.25 mg/l and an MIC90 less than or equal to 1 mg/l. It was not active against other species of Pseudomonas or other non-fermenters such as Flavobacterium sp.