A long-term study of gentamicin-resistant <i>Pseudomonas aeruginosa</i> in a general hospital

Abstract

The incidence of gentamicin resistance in Pseudomonas aeruginosa strains isolated from patients in a large teaching hospital was followed for 11 years beginning in 1968, the year after gentamicin was first used in the hospital. Among a total of 4570 strains of Ps. aeruginosa 293 were resistant (MIC ≥8 mg/l). For the first 5 years the proportion of resistant strains remained constant at around 5% and then rose to 8 to 9%. The increase was due to spread by cross-infection of two strains with permeability type resistance. Development of resistance during treatment of Ps. aeruginosa infections with gentamicin was infrequent. No relationship was seen between the incidence of resistance and the amount of gentamicin prescribed in the hospital.