Long-Term Control of Endemic Hospital-Wide Methicillin-Resistant Staphylococcus aureus (MRSA): The Impact of Targeted Active Surveillance for MRSA in Patients and Healthcare Workers

To evaluate the long-term impact of successive interventions on rates of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection and MRSA bacteremia in an endemic hospital-wide situation. DESIGN:Quasi-experimental, interrupted time-series analysis. The impact of the interventions was analyzed by use of segmented regression. Representative MRSA isolates were typed by use of pulsed-field gel electrophoresis. SETTING:A 950-bed teaching hospital in Seville, Spain. PATIENTS:All patients admitted to the hospital during the period from 1995 through 2008. METHODS:Three successive interventions were studied: (1) contact precautions, with no active surveillance for MRSA; (2) targeted active surveillance for MRSA in patients and healthcare workers in specific wards, prioritized according to clinical epidemiology data; and (3) targeted active surveillance for MRSA in patients admitted from other medical centers. RESULTS:Neither the preintervention rate of MRSA colonization or infection (0.56 cases per 1,000 patient-days [95% confidence interval {CI}, 0.49-0.62 cases per 1,000 patient-days]) nor the slope for the rate of MRSA colonization or infection changed significantly after the first intervention. The rate decreased significantly to 0.28 cases per 1,000 patient-days (95% CI, 0.17-0.40 cases per 1,000 patient-days) after the second intervention and to 0.07 cases per 1,000 patient-days (95% CI, 0.06-0.08 cases per 1,000 patient-days) after the third intervention, and the rate remained at a similar level for 8 years. The MRSA bacteremia rate decreased by 80%, whereas the rate of bacteremia due to methicillin-susceptible S. aureus did not change. Eighty-three percent of the MRSA isolates identified were clonally related. All MRSA isolates obtained from healthcare workers were clonally related to those recovered from patients who were in their care. CONCLUSION:Our data indicate that long-term control of endemic MRSA is feasible in tertiary care centers. The use of targeted active surveillance for MRSA in patients and healthcare workers in specific wards (identified by means of analysis of clinical epidemiology data) and the use of decolonization were key to the success of the program.

Nosocomial Outbreak of Infection With Pan-Drug-Resistant Acinetobacter baumannii in a Tertiary Care University Hospital

OBJECTIVE To describe what is, to our knowledge, the first nosocomial outbreak of infection with pan-drug-resistant (including colistin-resistant) Acinetobacter baumannii, to determine the risk factors associated with these types of infections, and to determine their clinical impact. DESIGN Nested case-control cohort study and a clinical-microbiological study. SETTING A 1,521-bed tertiary care university hospital in Seville, Spain. PATIENTS Case patients were inpatients who had a pan-drug-resistant A. baumannii isolate recovered from a clinical or surveillance sample obtained at least 48 hours after admission to an intensive care unit (ICU) during the time of the epidemic outbreak. Control patients were patients who were admitted to any of the "boxes" (ie, rooms that partition off a distinct area for a patient's bed and the equipment needed to care for the patient) of an ICU for at least 48 hours during the time of the epidemic outbreak. RESULTS All the clinical isolates had similar antibiotic susceptibility patterns (ie, they were resistant to all the antibiotics tested, including colistin), and, on the basis of repetitive extragenic palindromic-polymerase chain reaction, it was determined that all of them were of the same clone. The previous use of quinolones and glycopeptides and an ICU stay were associated with the acquisition of infection or colonization with pan-drug-resistant A. baumannii. To control this outbreak, we implemented the following multicomponent intervention program: the performance of environmental decontamination of the ICUs involved, an environmental survey, a revision of cleaning protocols, active surveillance for colonization with pan-drug-resistant A. baumannii, educational programs for the staff, and the display of posters that illustrate contact isolation measures and antimicrobial use recommendations. CONCLUSIONS We were not able to identify the common source for these cases of infection, but the adopted measures have proven to be effective at controlling the outbreak.