Fluoroquinolone use and fluoroquinolone resistance: is there an association?

In an assessment of potential risk factors for nosocomial infections caused by fluoroquinolone-resistant gram-negative organisms, 68 patients who developed a nosocomial infection caused by a fluoroquinolone-resistant gram-negative bacillus were compared with 191 patients who developed a nosocomial infection caused by a fluoroquinolone-susceptible gram-negative bacillus. A history of previous infection, immunosuppression, prior receipt of fluoroquinolones, and hospitalization on the burn unit were independent risk factors. Except for immunosuppression, the same risk factors were identified when the 50 patients whose isolates were resistant to fluoroquinolones, aminoglycosides, and beta-lactam antibiotics were compared with the 95 patients whose isolates were susceptible to all of these classes of antimicrobial agents. The identification of hospitalization on the burn unit as a risk factor was attributable to an outbreak of infections caused by a resistant strain of Pseudomonas aeruginosa during the study period. The occurrence of nosocomial outbreaks and the selective pressure of fluoroquinolone use were the main exogenous risk factors involved in the emergence of resistance to fluoroquinolones.