The incidence of life-threatening Gramnegative bacterial infections has increased strikingly during recent years.1,2 The majority of these arise within the hospital environment and often resist treatment with ordinarily effective antibiotics including the tetracyclines, streptomycin, and chloramphenicol.
The broad-spectrum, semisynthetic penicillins (ampicillin [Penbritin]) have not been effective against most severe hospital-acquired Gram-negative microorganisms.3 Kanamycin has been useful, but increasing numbers of microorganisms are now resistant to it 4 and it has considerable toxicity. Colistin is less hazardous and is especially valuable in Pseudomonas infections,5 but it is not satisfactory as a broad-spectrum antibiotic for hospital-acquired Gram-negative infections.
Recently, we have studied a new antibiotic, gentamicin.* It is a fermentation product of Micromonospora purpura, a member of the family Streptomycetaceae.6 In vitro studies by Weinstein et al 6 have indicated considerable activity against most Gram-negative organisms, including those resistant to most other antimicrobial agents. It is also active in vitro against some