ABSTRACT
From March 2009 to May 2009, 24 carbapenem-resistant Klebsiella pneumoniae isolates were recovered from 16 patients hospitalized in an Italian intensive care unit (ICU). All isolates contained KPC-3 carbapenemase and belonged to a single pulsed-field gel electrophoresis (PFGE) clone of multilocus sequence type 258 (designated as ST258). A multimodal infection control program was put into effect, and the spread of the KPC-3-producing K. pneumoniae clone was ultimately controlled without closing the ICU to new admissions. Reinforced infection control measures and strict monitoring of the staff adherence were necessary for the control of the outbreak.
Subject(s)
Bacterial Proteins/metabolism , Cross Infection/epidemiology , Disease Outbreaks , Infection Control/methods , Klebsiella Infections/epidemiology , Klebsiella pneumoniae/enzymology , beta-Lactamases/metabolism , Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Cluster Analysis , Cross Infection/prevention & control , Electrophoresis, Gel, Pulsed-Field , Humans , Intensive Care Units , Italy/epidemiology , Klebsiella Infections/prevention & control , Klebsiella pneumoniae/classification , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/isolation & purification , Molecular Typing , beta-Lactam ResistanceABSTRACT
Acinetobacter baumannii and Stenotrophomonas maltophilia are increasingly important pathogens, especially in the intensive care units (ICUs). This study was designed to investigate the clonality, the mode of transmission and the patients' risk profile for acquisition of A. baumannii and S. maltophilia at the ICU of an Italian Hospital. Patterns of A. baumannii and S. maltophilia acquisition in the ICU during the period of the survey were carriage, colonization and infection. Characterization of A. baumannii was performed by ARDRA and genotyping of both pathogens by PFGE. Our study provided evidence for the occurrence of an outbreak sustained by the two organisms in study involving 27.3% of patients enrolled into the surveillance. The spread of a unique A. baumannii epidemic clone was demonstrated. A major clone of S. maltophilia was responsible for the epidemic spread of S. maltophilia (55.5% of isolates), thus confirming A. baumannii cross-transmission and showing--among few published reports--the clonal spread of S. maltophilia. Outliers analysis suggested colonized patients as the probable epidemic sources. Mechanical ventilation was confirmed as risk factor for infection (OR 8.4; 95%C.I.: 2.6-27.5). A multimodal intervention program was introduced, followed in later months with a drastic restriction of infection and colonization due to A. baumannii and S. maltophilia and subsequently with the successful control of the outbreak. Active surveillance of infection and colonization by high-risk clones, together with implementation of control strategies, including strict hand hygiene, proved to be effective to reduce the epidemic spread of both alert pathogens in our ICU.
Subject(s)
Acinetobacter Infections/transmission , Acinetobacter baumannii , Disease Outbreaks , Gram-Negative Bacterial Infections/transmission , Stenotrophomonas maltophilia , Acinetobacter Infections/epidemiology , Acinetobacter baumannii/classification , Acinetobacter baumannii/genetics , Acinetobacter baumannii/isolation & purification , Case-Control Studies , Clone Cells , Critical Care , Cross Infection/epidemiology , Cross Infection/transmission , Drug Resistance, Multiple, Bacterial , Gram-Negative Bacterial Infections/epidemiology , Humans , Infection Control , Intensive Care Units , Renal Insufficiency, Chronic/complications , Respiration, Artificial/adverse effects , Risk Factors , Stenotrophomonas maltophilia/classification , Stenotrophomonas maltophilia/genetics , Stenotrophomonas maltophilia/isolation & purificationABSTRACT
OBJECTIVE: We evaluated whether Pseudomonas aeruginosa associated nosocomial infections in our ICU originate mainly from patients' endogenous flora or from exogenous cross-transmission. DESIGN AND SETTING: A 6-month prospective surveillance survey was performed according to standardized protocols at the interdisciplinary ICU of the Azienda Ospedaliera Cannizzaro. PATIENTS: The study analyzed 121 patients and focused on three different states: carriage upon admission, colonization of sterile sites, and infections during ICU stay. RESULTS: We identified 138 P. aeruginosa isolates from 45 patients. The cumulative incidence of P. aeruginosa sustained colonization in the ICU was 29.9/100 patients, and the incidence density was 16.2/1,000 patient-days. The cumulative incidence of P. aeruginosa-sustained infections in the ICU was 36.7/100 patients, and the incidence density was 19.9/1,000 patient-days. The most frequent infection type was ventilator-associated pneumonia. PFGE analysis of P. aeruginosa isolates led to the identification of a major clone represented by 60.8% of isolates involving 45.9% of patients. The impact of cross-transmission, i.e., the preventable proportion of P. aeruginosa acquisition, was estimated to be at least 59.5% of all colonization or infection episodes. Acquisition of multidrug-resistant P. aeruginosa was significantly associated with cross-transmission. CONCLUSIONS: Our results suggest that the ICU personnel and environment served as reservoirs for cross-transmission and emphasize the importance of exogenous acquisition of multidrug-resistant P. aeruginosa, of reduction in antibiotic pressure, and prompt enforcement of infection control measures.
