JAC Advance Access originally published online on July 29, 2003
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Journal of Antimicrobial Chemotherapy (2003) 52, 457-463
© 2003 The British Society for Antimicrobial Chemotherapy
Characterization of the onset and consequences of pneumonia due to fluoroquinolone-susceptible or -resistant Pseudomonas aeruginosa
1 CPL Associates LLC, 3980 Sheridan Drive, Suite 501, Amherst, NY 14226-1727; 2 The University at Buffalo School of Pharmacy, Buffalo, NY, USA
Received 24 February 2003; returned 15 April 2003; revised 21 May 2003; accepted 29 May 2003
Objectives: This study was conducted to identify and compare the microbiological and clinical outcomes among hospitalized adults with pneumonia caused by fluoroquinolone-susceptible or -resistant strains of Pseudomonas aeruginosa. Antibiotic regimens used prior to, as well as those used to treat, the infections were characterized.
Patients and methods: This non-randomized multicentre study included 100 consecutively identified patients with pneumonia caused by fluoroquinolone-susceptible (n = 50) or fluoroquinolone-resistant (n = 50) strains of P. aeruginosa. Medical records were examined for demographic, clinical and treatment variables including antibiotics received in the 30 days before the index respiratory or blood culture; AUICs were calculated for each patient using reported or derived MICs. Multivariate logistic and linear regressions were used to identify factors associated with successful clinical and microbiological outcomes.
Results: The study population was primarily elderly, frequently in a critical care unit, with low serum albumin and with a high probability of failure and mortality. Patients with pneumonia caused by fluoroquinolone-resistant P. aeruginosa were more likely to have received antibiotics within 7 days before the infection (P = 0.027); the antibiotic regimen was more likely to be of a weak potency (mean AUIC of 58 versus 169, P = 0.001) and to include levofloxacin (P < 0.0001) than what was administered to patients who became infected with a fluoroquinolone-susceptible strain. Regardless of susceptibility, a mean of between 2 and 3 weeks of directed antibiotic therapy was administered to each patient.
Conclusions: Pneumonia caused by fluoroquinolone-resistant P. aeruginosa is frequently associated with prior exposure to levofloxacin. Treatment of P. aeruginosa pneumonia is difficult and usually consists of combination regimens with multiple modifications.
Keywords: AUIC, predictive, outcomes
* Corresponding author. Tel: +1-716-839-4931; Fax: +1-716-839-5138; E-mail: paladino{at}cplassociates.com