Factors associated with acquisition of Pseudomonas aeruginosa resistant to gentamicin.

Concern over the increased occurrence of Pseudomonas aeruginosa resistant to gentamicin colonizing and/or causing disease in patients prompted our review of the years 1974 and 1975 for all P aeruginosa isolates, both gentamicin-resistant and gentamicin-sensitive. In this period, 39 patients had gentamicin-resistant P aeruginosa recovered from clinical specimens while 683 patients had gentamicin-sensitive strains. Compared to both matched and/or randomly selected controls with gentamicin-sensitive infections, patients with gentamicin-resistant infections had a higher incidence of (1) prior antibiotic therapy (p less than 0.01), (2) prior therapy with gentamicin (p less than 0.005), and (3) exposure to multiple antibiotics.