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.
OBJECTIVE
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.


METHODS
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.


METHODS
A 950-bed teaching hospital in Seville, Spain.


METHODS
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.


CONCLUSIONS
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.
Sección de Enfermedades Infecciosas, Servicio de Microbiología, Hospital Universitario Virgen Macarena, and the Departamento de Medicina, Universidad de Sevilla, Sevilla, Spain. jesusrb@us.es
Jesús
J
Rodríguez-Baño
Lola
L
García
Encarnación
E
Ramírez
Carmen
C
Lupión
Miguel A
MA
Muniain
Carmen
C
Velasco
Juan
J
Gálvez
M Dolores
MD
del Toro
Antonio B
AB
Millán
Lorena
L
López-Cerero
Alvaro
A
Pascual
D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D019353:Endemic Diseases / Q000517:prevention & control*; D006282:Health Personnel; D006785:Hospitals, University; D006801:Humans; D017053:Infection Control / Q000379:methods*; D007297:Inpatients; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D011159:Population Surveillance / Q000379:methods*; D015397:Program Evaluation; D013030:Spain; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification