title: Comorbidities and disease severity as risk factors for carbapenem-resistant Klebsiella pneumoniae colonization: report of an experience in an internal medicine unit.
abstract: BACKGROUND
  Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging multidrug-resistant nosocomial pathogen, spreading to hospitalized elderly patients. Risk factors in this setting are unclear. Our aims were to explore the contribution of multi-morbidity and disease severity in the onset of CRKP colonization/infection, and to describe changes in epidemiology after the institution of quarantine-ward managed by staff-cohorting.
  
  
  RESULTS
  With a case-control design, we evaluated 133 CRKP-positive patients (75 M, 58 F; mean age 79 ± 10 years) and a control group of 400 CRKP-negative subjects (179 M, 221 F; mean age 79 ± 12 years) admitted to Internal Medicine and Critical Subacute Care Unit of Parma University Hospital, Italy, during a 10-month period. Information about comorbidity type and severity, expressed through Cumulative Illness Rating Scale-CIRS, was collected in each patient. During an overall 5-month period, CRKP-positive patients were managed in an isolation ward with staff cohorting. A contact-bed isolation approach was established in the other 5 months. The effects of these strategies were evaluated with a cross-sectional study design. CRKP-positive subjects had higher CIRS comorbidity index (12.0 ± 3.6 vs 9.1 ± 3.5, p < 0.0001) and CIRS severity index (3.2 ± 0.4 vs 2.9 ± 0.5, p < 0.0001), along with higher cardiovascular, respiratory, renal and neurological disease burden than control group. CIRS severity index was associated with a higher risk for CRKP-colonization (OR 13.3, 95% CI6.88-25.93), independent of comorbidities. Isolation ward activation was associated with decreased monthly incidence of CRKP-positivity (from 16.9% to 1.2% of all admissions) and infection (from 36.6% to 22.5% of all positive cases; p = 0.04 derived by Wilcoxon signed-rank test). Mortality rate did not differ between cases and controls (21.8% vs 15.2%, p = 0.08). The main limitations of this study are observational design and lack of data about prior antibiotic exposure.
  
  
  CONCLUSIONS
  Comorbidities and disease severity are relevant risk factors for CRKP-colonization/infection in elderly frail patients. Sanitary measures may have contributed to limit epidemic spread and rate of infection also in internal medicine setting.
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy; Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nouvenne
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy; Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ticinesi
authors.affiliation: Geriatrics Unit, Parma University Hospital, Parma, Italy.
authors.forename: Fulvio
authors.initials: F
authors.lastname: Lauretani
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Maggio
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, Parma University Hospital, Parma, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lippi
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Guida
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Morelli
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy; Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Erminia
authors.initials: E
authors.lastname: Ridolo
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy; Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: Borghi
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Parma University Hospital, Parma, Italy; Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Meschi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015780:Carbapenems / Q000627:therapeutic use*; D016022:Case-Control Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007710:Klebsiella Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology*; D007711:Klebsiella pneumoniae; D008297:Male; D012307:Risk Factors; D012720:Severity of Illness Index; D018440:beta-Lactam Resistance
chemical_list: D015780:Carbapenems