Is fluoroquinolone monotherapy a useful alternative treatment for Pseudomonas aeruginosa bacteraemia?

Purpose: Pseudomonas aeruginosa bacteraemia is associated with high mortality, and most monotherapies are beta-lactam-based. We aimed to investigate clinical outcomes of definitive fluoroquinolone monotherapy versus beta-lactam monotherapy for P. aeruginosa bacteraemia. Methods: This retrospective study enrolled adult patients receiving definitive monotherapy with beta-lactam or fluoroquinolone between November 2013 and November 2014 at Taipei Veterans General Hospital. The independent risk factors for 28-day mortality were analyzed by logistic regression and propensity score-adjusted analysis. Results: Among the 105 patients enrolled, 78 patients received beta-lactams and 27 received fluoroquinolones (20 with ciprofloxacin and 7 with levofloxacin). Primary bacteraemia (39.0%) and urinary tract infections (37.1%) were the most common sources of bacteraemia. The 28-day mortality rate was 11.1% for those receiving fluoroquinolones and 32.1% for those receiving beta-lactams (P = 0.062). The 28-day mortality rate between the two groups stratified by APACHE II and Pitt bacteraemia scores showed no significant differences in each category. Propensity score-adjusted multivariate analysis revealed that definitive therapy with a fluoroquinolone was not associated with 28-day mortality (OR 0.42; 95% CI 0.08–2.23; P = 0.305). Conclusions: Fluoroquinolone might be an alternative to beta-lactam as a definitive monotherapy for P. aeruginosa bacteraemia provided they are active in vitro. Our results could be a basis for further studies and provide a possible target for antibiotic stewardship interventions in P. aeruginosa bacteraemia.