title: Clinical epidemiology, treatment and prognostic factors of extensively drug-resistant Acinetobacter baumannii ventilator-associated pneumonia in critically ill patients.
abstract: Limited data exist regarding prognostic factors and optimal antimicrobial treatment of infections caused by extensively drug-resistant Acinetobacter baumannii (XDR-AB). This retrospective cohort study included 93 adult patients who developed ventilator-associated pneumonia (VAP) due to XDR-AB in the ICU of the University Hospital of Heraklion, Greece, from October 2012 to April 2015. XDR-AB isolates were mainly susceptible to colistin (93.5%) and tigecycline (25.8%), whereas 6 (6.5%) were pandrug-resistant. Prior to infection, patients had long durations of mechanical ventilation and hospital stay and multiple exposures to antibiotics. Median Charlson co-morbidity and APACHE II scores were 2 and 17, respectively. Mortality at 28 days of infection onset was high (34.4%) despite high rates of in-vitro-active empirical (81.7%) and definitive (90.3%) treatment. Active colistin-based combination therapy (n = 55) and monotherapy (n = 29) groups had similar 28-day mortality (27.6% vs. 30.9%, respectively) and Kaplan-Meier survival estimates over time. In multivariable Cox regression, advanced age (aHR = 1.05 per year increase, 95% CI 1.02-1.09), rapidly fatal underlying disease (aHR = 2.64, 95% CI 0.98-9.17) and APACHE II score (aHR = 1.06 per unit increase, 95% CI 0.99-1.14) were identified as independent predictors of 28-day mortality, but no difference in mortality hazards between the active colistin-based combination therapy and monotherapy groups was produced (aHR = 0.88, 95% CI 0.35-2.38). These results support the use of colistin as a first-line agent against VAP in settings where XDR-AB is endemic, but oppose the introduction of colistin-based combination therapy as standard treatment.
authors.affiliation: Department of Internal Medicine/Infectious Diseases, University Hospital of Heraklion, 71110 Iraklio, Crete, Greece. Electronic address: kostsioutis@gmail.com.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Tsioutis
authors.affiliation: School of Health and Related Research, University of Sheffield, Sheffield, UK.
authors.forename: Evangelos I
authors.initials: EI
authors.lastname: Kritsotakis
authors.affiliation: Department of Internal Medicine/Infectious Diseases, University Hospital of Heraklion, 71110 Iraklio, Crete, Greece.
authors.forename: Spyridon A
authors.initials: SA
authors.lastname: Karageorgos
authors.affiliation: Department of Internal Medicine/Infectious Diseases, University Hospital of Heraklion, 71110 Iraklio, Crete, Greece.
authors.forename: Soultana
authors.initials: S
authors.lastname: Stratakou
authors.affiliation: Intensive Care Medicine Department, University Hospital of Heraklion, Crete, Greece.
authors.forename: Charalambos
authors.initials: C
authors.lastname: Psarologakis
authors.affiliation: Intensive Care Medicine Department, University Hospital of Heraklion, Crete, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Kokkini
authors.affiliation: Department of Internal Medicine/Infectious Diseases, University Hospital of Heraklion, 71110 Iraklio, Crete, Greece.
authors.forename: Achilleas
authors.initials: A
authors.lastname: Gikas
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003091:Colistin / Q000494:pharmacology / Q000627:therapeutic use; D016638:Critical Illness; D024901:Drug Resistance, Multiple, Bacterial; D004359:Drug Therapy, Combination / Q000379:methods; D005260:Female; D006115:Greece / Q000453:epidemiology; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000188:drug therapy / Q000453:epidemiology* / Q000401:mortality* / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D003091:Colistin
keywords: Acinetobacter; Antimicrobial resistance; Colistin; Extensively drug-resistant; Treatment; Ventilator-associated pneumonia