Optimal management therapy for Pseudomonas aeruginosa ventilator-associated pneumonia: an observational, multicenter study comparing monotherapy with combination antibiotic therapy.
OBJECTIVE
To evaluate whether one antibiotic achieves equal outcomes compared with combination antibiotic therapy in patients with Pseudomonas aeruginosa ventilator-associated pneumonia.


METHODS
A retrospective, multicenter, observational, cohort study.


METHODS
Five intensive care units in Spanish university hospitals.


METHODS
Adult patients identified to have monomicrobial episodes of ventilator-associated pneumonia with significant quantitative respiratory cultures for P. aeruginosa.


METHODS
None.


RESULTS
A total of 183 episodes of monomicrobial P. aeruginosa ventilator-associated pneumonia were analyzed. Monotherapy alone was used empirically in 67 episodes, being significantly associated with inappropriate therapy (56.7% vs. 90.5%, p < .001). Hospital mortality was significantly higher in the 40 patients with inappropriate therapy compared with those at least on antibiotic with activity in vitro (72.5% vs. 23.1%, p < .05). Excess mortality associated with monotherapy was estimated to be 13.6% (95% confidence interval -2.6 to 29.9). The use of monotherapy or combination therapy in the definitive regimen did not influence mortality, length of stay, development of resistance to the definitive treatment, or appearance of recurrences. Inappropriate empirical therapy was associated with increased mortality (adjusted hazard ratio 1.85; 95% confidence interval 1.07-3.10; p = .02) in a Cox proportional hazard regression analysis, after adjustment for disease severity, but not effective monotherapy (adjusted hazard ratio 0.90; 95% confidence interval 0.50-1.63; p = .73) compared with effective combination therapy (adjusted hazard ratio 1). The other two variables also independently associated with mortality were age (adjusted hazard ratio 1.02; 95% confidence interval 1.01-1.04; p = .005) and chronic cardiac insufficiency (adjusted hazard ratio 1.90; 95% confidence interval 1.04-3.47; p = .035).


CONCLUSIONS
Initial use of combination therapy significantly reduces the likelihood of inappropriate therapy, which is associated with higher risk of death. However, administration of only one effective antimicrobial or combination therapy provides similar outcomes, suggesting that switching to monotherapy once the susceptibility is documented is feasible and safe.
Garnacho-Montero
Jose
J
Critical Care and Emergency Department, Hospital Universitario Virgen del Rocio, Sevilla, Spain. jose.garnacho.sspa@juntadeandalucia.es
Sa-Borges
Marcio
M
Sole-Violan
Jordi
J
Barcenilla
Fernando
F
Escoresca-Ortega
Ana
A
Ochoa
Miriam
M
Cayuela
Aurelio
A
Rello
Jordi
J
D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D024881:Drug Resistance, Bacterial; D004359:Drug Therapy, Combination; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D053717:Pneumonia, Ventilator-Associated / Q000188:drug therapy* / Q000401:mortality; D016016:Proportional Hazards Models; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000401:mortality; D012189:Retrospective Studies; D012772:Shock, Septic / Q000188:drug therapy / Q000401:mortality; D013030:Spain / Q000453:epidemiology; D016019:Survival Analysis
D000900:Anti-Bacterial Agents