title: Prospective multicenter study of the impact of carbapenem resistance on mortality in Pseudomonas aeruginosa bloodstream infections.
abstract: The impact of antimicrobial resistance on clinical outcomes is the subject of ongoing investigations, although uncertainty remains about its contribution to mortality. We investigated the impact of carbapenem resistance on mortality in Pseudomonas aeruginosa bacteremia in a prospective multicenter (10 teaching hospitals) observational study of patients with monomicrobial bacteremia followed up for 30 days after the onset of bacteremia. The adjusted influence of carbapenem resistance on mortality was studied by using Cox regression analysis. Of 632 episodes, 487 (77%) were caused by carbapenem-susceptible P. aeruginosa (CSPA) isolates, and 145 (23%) were caused by carbapenem-resistant P. aeruginosa (CRPA) isolates. The median incidence density of nosocomial CRPA bacteremia was 2.3 episodes per 100,000 patient-days (95% confidence interval [CI], 1.9 to 2.8). The regression demonstrated a time-dependent effect of carbapenem resistance on mortality as well as a significant interaction with the Charlson index: the deleterious effect of carbapenem resistance on mortality decreased with higher Charlson index scores. The impact of resistance on mortality was statistically significant only from the fifth day after the onset of the bacteremia, reaching its peak values at day 30 (adjusted hazard ratio for a Charlson score of 0 at day 30, 9.9 [95% CI, 3.3 to 29.4]; adjusted hazard ratio for a Charlson score of 5 at day 30, 2.6 [95% CI, 0.8 to 8]). This study clarifies the relationship between carbapenem resistance and mortality in patients with P. aeruginosa bacteremia. Although resistance was associated with a higher risk of mortality, the study suggested that this deleterious effect may not be as great during the first days of the bacteremia or in the presence of comorbidities.
authors.affiliation: Servicio de Enfermedades Infecciosas, Hospital Universitario de Bellvitge-IDIBELL, Barcelona, Spain. cpena@bellvitgehospital.cat
authors.forename: Carmen
authors.initials: C
authors.lastname: Peña
authors.forename: Cristina
authors.initials: C
authors.lastname: Suarez
authors.forename: Mónica
authors.initials: M
authors.lastname: Gozalo
authors.forename: Javier
authors.initials: J
authors.lastname: Murillas
authors.forename: Benito
authors.initials: B
authors.lastname: Almirante
authors.forename: Virginia
authors.initials: V
authors.lastname: Pomar
authors.forename: Manuela
authors.initials: M
authors.lastname: Aguilar
authors.forename: Ana
authors.initials: A
authors.lastname: Granados
authors.forename: Esther
authors.initials: E
authors.lastname: Calbo
authors.forename: Jesús
authors.initials: J
authors.lastname: Rodríguez-Baño
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodríguez
authors.forename: Fe
authors.initials: F
authors.lastname: Tubau
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez-Martínez
authors.forename: Antonio
authors.initials: A
authors.lastname: Oliver
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D015780:Carbapenems / Q000008:administration & dosage*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000254:growth & development; D012044:Regression Analysis; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems