title: Extensively drug-resistant Pseudomonas aeruginosa: risk of bloodstream infection in hospitalized patients.
abstract: Several studies have suggested that resistance determinants usually reduce virulence. However, their contribution to decrease bloodstream infections is unclear. Our aim was to identify risk factors of extensively drug-resistant (XDR) Pseudomonas aeruginosa (PA) bacteremia and to assess the prevalence of XDR-PA bacteremia. A retrospective study of PA bloodstream infections in our patient population with at least one clinical sample isolate due to PA (2006-2007) was carried out. A total of 2,131 patients with PA clinical samples were detected. Among 1,657 patients with susceptible-PA isolates, 95 developed PA-susceptible bacteremia. Concomitantly, among 474 patients with multidrug-resistant (MDR)-PA isolates, 265 with XDR-PA, and 209 with non-XDR MDR-PA, 43 developed XDR-PA bacteremia and 13 non-XDR MDR-PA bacteremia, respectively. Pulsed-field gel electrophoresis (PFGE) revealed the clonal nature of the two predominant XDR-PA phenotypes and genetic heterogeneity in non-XDR MDR-PA phenotypes. The proportion of XDR-PA bacteremia was higher than the proportion of bacteremia in the susceptible-PA population (16 % vs. 6 %; p < 0.001). A logistic regression model identified prior exposure to fluoroquinolones [odds ratio (OR) 2.80; 95 % confidence interval (CI) 1.02 to 7.70] as the independent variable associated with XDR-PA bacteremia. Our study suggests that XDR-PA strains have a greater ability to develop bacteremia. It remains unclear as to whether this invasive capacity depends on clonal traits or on other virulence determinants.
authors.affiliation: Infectious Diseases Service, IDIBELL, Hospital Universitari de Bellvitge, Barcelona, Spain. cpena@bellvitgehospital.cat
authors.forename: C
authors.initials: C
authors.lastname: Peña
authors.forename: S
authors.initials: S
authors.lastname: Gómez-Zorrilla
authors.forename: C
authors.initials: C
authors.lastname: Suarez
authors.forename: M A
authors.initials: MA
authors.lastname: Dominguez
authors.forename: F
authors.initials: F
authors.lastname: Tubau
authors.forename: O
authors.initials: O
authors.lastname: Arch
authors.forename: A
authors.initials: A
authors.lastname: Oliver
authors.forename: M
authors.initials: M
authors.lastname: Pujol
authors.forename: J
authors.initials: J
authors.lastname: Ariza
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D016001:Confidence Intervals; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology; D018740:Genetic Heterogeneity; D006760:Hospitalization; D006801:Humans; D016015:Logistic Models; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D012189:Retrospective Studies; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones