Characterization of the onset and consequences of pneumonia due to fluoroquinolone-susceptible or -resistant Pseudomonas aeruginosa.
OBJECTIVE
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.


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.
Paladino
Joseph A
JA
CPL Associates LLC, 3980 Sheridan Drive, Suite 501, Amherst, NY 14226-1727, USA. paladino@cplassociates.com
Sunderlin
Jenna L
JL
Forrest
Alan
A
Schentag
Jerome J
JJ
D000368:Aged; D000900:Anti-Bacterial Agents / Q000191:economics / Q000494:pharmacology* / Q000627:therapeutic use; D019540:Area Under Curve; D024881:Drug Resistance, Bacterial; D005260:Female; D024841:Fluoroquinolones / Q000191:economics / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D064704:Levofloxacin; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015242:Ofloxacin / Q000009:adverse effects / Q000627:therapeutic use; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000191:economics / Q000382:microbiology*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000191:economics / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D064704:Levofloxacin; D015242:Ofloxacin