title: Changed epidemiology of ICU acquired bloodstream infections over 12 years in an Italian teaching hospital.
abstract: BACKGROUND
  We compared the etiology of 203 ICU-acquired laboratory confirmed bloodstream infections (LC-BSI) prospectively collected between January 2000-December 2007 (first period) with 83 LC-BSI recorded between January 2010-December 2012 (second period), after the diffusion in 2008 of K. pneumoniae expressing carbapenem-resistance due to K. pneumoniae carbapenemases production (KPC-CR-Kp).
  
  
  METHODS
  In the general ICU of teaching hospital "Umberto I" in Rome, all ICU-acquired LC-BSI episodes occurring in patients admitted to ICU≥48h were included. Baseline characteristics, clinical features, antimicrobial resistance and outcome were recorded. All isolated strains multidrug resistance (MDR) were evaluated according to the European Centre for Disease Control (ECDC) guidelines.
  
  
  RESULTS
  Overall the study included 329 isolates, 214 in 2000-2007 and 115 in 2010-2012. In the second period we registered a Gram-positive reduction (55.1% vs. 26.9%; P<0.01) and Gram-negative increase (40.2% vs. 69.6%; P<0.01). In 2000-2007 staphylococci were responsible for 45.8% LC-BSI's, whereas 18.3% during 2010-2012. Enterobacteriaceae increased dramatically (15.4% vs. 39.2%; P<0.01), especially Klebsiella spp. (5.6% vs. 31.3%; P<0.01). LC-BSI associated mortality decreased among Gram-positive (56.8% vs. 51.6%), but increased in Gram-negative (41.9% vs. 60.0%; P<0.03), especially in Enterobacteriaceae (RR 2.13; 95% CI 1.21 - 3.73; P<0.01). MDR increased remarkably among Enterobacetriaceae (51.5% vs. 73.3%). The study highlighted the associated mortality for Enterobacteriaceae when comparing MDR to non-MDR microorganisms.
  
  
  CONCLUSIONS
  ICU-acquired LC-BSI etiology shifted from Gram-positive to Gram-negative during the study period in our ICU. Also associated mortality decreased among the former, whereas it increased in the latter. Last MDR increased enormously among Enterobacteriaceae with the diffusion of KPC (75% of strains), adding significantly to associated mortality (RR 2.17; 1.16-4.05; P<0.01).
authors.affiliation: Department of Public Health and Infectious Diseases, "Sapienza" University of Rome, Rome, Italy - giovanni.orsi@uniroma1.it.
authors.forename: G B
authors.initials: GB
authors.lastname: Orsi
authors.forename: S
authors.initials: S
authors.lastname: Giuliano
authors.forename: C
authors.initials: C
authors.lastname: Franchi
authors.forename: V
authors.initials: V
authors.lastname: Ciorba
authors.forename: C
authors.initials: C
authors.lastname: Protano
authors.forename: A
authors.initials: A
authors.lastname: Giordano
authors.forename: M
authors.initials: M
authors.lastname: Rocco
authors.forename: M
authors.initials: M
authors.lastname: Venditti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D024881:Drug Resistance, Bacterial; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology; D017052:Hospital Mortality; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies