Table 4Multivariate analysis, factors associated with ICU and hospital death after adjusting on potential confounding factorsSimilarly, resistance to imipenem, ceftazidime, amikacin, ciprofloxacin and colistin (Figure (Figure2)2) was not associated with ICU death or hospital death.Figure 2Resistance to other inhibitor Ixazomib antimicrobials of ureido/carboxy susceptible and resistant strains (n = 129). AMK, amikacine; CFP, cefepime; CIP, ciprofloxacin; COL, colimycin; CTZ, Ceftazidime; IMI, Imipenem; PR-PA piperacillin-resistant P. aeruginosa; PSPA, piperacillin-susceptible …The results remained unchanged when analysis was restricted to the 87 patients adequately treated the day of the infection onset (OR for ICU mortality 1.22 (95% CI, 0.31 to 4.78; P = 0.78); OR for hospital mortality, 1.10 (95% CI, 0.

29 to 4.10; P = 0.89)).DiscussionTo date, our study is one of the largest to have evaluated the impact of piperacillin resistance in PA-VAP [9,10]. All data were carefully recorded by senior physicians on computer forms. Definitions and antimicrobial treatments were in accordance with international guidelines. The major result is that piperacillin resistance is associated with a higher rate of inappropriate antimicrobial therapy. Unadjusted mortality was similar in PSPA-VAP and PRPA-VAP groups. After careful adjustment for time in the ICU at VAP diagnosis and for parameters that differ between the PRPA and the PSPA groups (severity at admission, previous antibiotic treatment, and adequacy of antimicrobial treatment), piperacillin resistance was found to not be associated with ICU or hospital death in the multivariate logistic regression analysis.

We observed a high rate of P. aeruginosa strains resistant to piperacillin (31%). This is in agreement with previous studies conducted Dacomitinib in Europe [16]. The percentage of P. aeruginosa resistance to ureidopenicillin reached 37% in the EPIC I study which included only bacterial strains from the European ICU [17]. The pathogenicity of P. aeruginosa is multifactorial, strain-specific, and dependent on complex host factors. Morbidity and mortality for patients infected with piperacillin resistant P. aeruginosa might be related to the virulence of the bacteria but also to the antimicrobial treatment administered. Both virulence factor genes and antimicrobial resistance genes are mostly carried by transposons and integrons, that is, genetic entities able to mediate their own translocation from one DNA site to another one. Integrons are particularly dominant contributors to the development of multi-drug resistant P. aeruginosa strains [8].Conceivably PRPA strains may be more virulent than PSPA strains. P.