Only limited data exist on Pseudomonas aeruginosa
ventilator-associated pneumonia (VAP) treated with
imipenem,
meropenem, or
doripenem. Therefore, we conducted a prospective observational study in 169 patients who developed Pseudomonas aeruginosa VAP.
Imipenem,
meropenem, and
doripenem MICs for Pseudomonas aeruginosa isolates were determined using Etests and compared according to the
carbapenem received. Among the 169 isolates responsible for the first VAP episode,
doripenem MICs were lower (P<0.0001) than those of
imipenem and
meropenem (MIC50s, 0.25, 2, and 0.38, respectively); 61%, 64%, and 70% were susceptible to
imipenem,
meropenem, and
doripenem, respectively (P was not statistically significant). Factors independently associated with
carbapenem resistance were previous
carbapenem use (within 15 days) and
mechanical ventilation duration before VAP onset. Fifty-six (33%) patients had at least one VAP recurrence, and 56 (33%) died. Factors independently associated with an unfavorable outcome (recurrence or death) were a high day 7 sequential organ failure assessment score and
mechanical ventilation dependency on day 7. Physicians freely prescribed a
carbapenem to 88 patients:
imipenem for 32,
meropenem for 24, and
doripenem for 32. The remaining 81 patients were treated with various
antibiotics.
Imipenem-,
meropenem-, and
doripenem-treated patients had similar VAP recurrence rates (41%, 25%, and 22%, respectively; P=0.15) and mortality rates (47%, 25%, and 22%, respectively; P=0.07).
Carbapenem resistance emerged similarly among patients treated with any
carbapenem. No
carbapenem was superior to another for preventing
carbapenem resistance emergence.