Polymyxin B versus other antimicrobials for the treatment of pseudomonas aeruginosa bacteraemia.
OBJECTIVE
to compare the efficacy of intravenous polymyxin B with other antimicrobials in the treatment of nosocomial Pseudomonas aeruginosa bacteraemia, assessing many potential confounding factors, including optimal dosage regimens of drugs.


METHODS
a retrospective cohort study was performed. Patients ≥ 18 years of age and who received appropriate therapy for ≥ 48 h for P. aeruginosa bacteraemia were analysed. Clinical covariates were assessed and compared between patients treated with polymyxin B and other drugs (comparators). Data were retrieved from medical records. Renal toxicity was also assessed. A Cox regression model was performed including variables with a P  ≤  0.20 in the comparison between both groups.


RESULTS
a total of 133 patients were included: 45 (33.8%) treated with polymyxin B and 88 (66.2%) with comparators. Most comparators (83.0%) were β-lactams. The overall in-hospital mortality was 41.4% (55/133): 66.7% (30/45) and 28.4% (25/88) in polymyxin B and comparator groups, respectively (P  ≤  0.001). The final multivariate model showed that treatment with polymyxin B was independently associated with in-hospital mortality (adjusted hazard ratio 1.91, 95% confidence interval 1.05-3.45), after adjustment for Pitt bacteraemia score, and the presence of mechanical ventilation and primary bloodstream infection. Patients treated with polymyxin B presented a higher rate of ≥ 100% increase in creatinine level from baseline than comparators [11/45 (24.4%) versus 4/88 (4.5%); P = 0.002], although this was not subjected to multivariate analysis.


CONCLUSIONS
intravenous polymyxin B therapy was inferior to other drugs in the treatment of P. aeruginosa bacteraemia, as indicated by the higher rate of in-hospital mortality.
Post-graduate Program in Medicine: Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Carlos H
CH
Kvitko
Maria H
MH
Rigatto
Ana L
AL
Moro
Alexandre P
AP
Zavascki
D058186:Acute Kidney Injury / Q000139:chemically induced; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000009:adverse effects; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology* / Q000401:mortality; D015331:Cohort Studies; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D011112:Polymyxin B / Q000008:administration & dosage* / Q000009:adverse effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D011112:Polymyxin B