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BOSTON -- Screening incoming hospital patients to see who's carrying methicillin-resistant Staphylococcus aureus (MRSA) can sharply reduce disease caused by the organism, a researcher said here.
Over a 10-year period, screening incoming patients resulted in a 70% drop in MRSA disease, according to Donna Schora, MT (ASCP), of the NorthShore University Health System in Evanston, Ill.
But over the decade the hospital system's infection control experts learned two things: there's no need to decolonize carriers and not all patients have to be screened, Schora reported at ASM Microbe 2016.
NorthShore, which has four facilities and 800 beds with 62,500 admissions a year, was the first hospital system in the country to begin active surveillance testing for MRSA carriage, using nasal swabs on admission, Schora said.
The system had been watching for MRSA just using positive cultures and had been checking patients on admission to the intensive care unit. But a point prevalence study in 2004 showed that 8.9% of patients carried MRSA, with just a third of them in the ICU.
"Basically, two-thirds of our positive patients were unknown to us," Schora said -- something that upset the infection control and nursing departments.
So, in 2005, NorthShore began swabbing all incoming patients and using polymerase chain reaction tests to deliver results within a median of 15 hours. Patients found to be harboring the bacteria were identified as colonized in their medical records, placed in gown and glove isolation, and decolonized using nasal mupirocin for 5 days and chlorhexidine baths on days 1, 3, and 5.
Before any screening, Schora said, the baseline rate of MRSA disease was 8.9 cases per 10,000 patient-days. Using just the ICU-admission screening cut the rate to 7.4, a difference that was significant compared with the baseline.
But a year and a half after the universal screening started the rate had fallen to 3.9 cases per 10,000 patient-days, which was significantly better than either of the earlier rates.
In 2010, NorthShore added a nearby hospital to the system, a facility that was only screening for nasal MRSA in the ICU, was using cultures to identify bacteria, and was not decolonizing any patients.
The institution decided it was a good opportunity to look at the effect of decolonization. Universal screening began, combined with contact precautions, but with decolonization in one period and without during another.
It turned out that there was no difference in the rate of MRSA disease. "We concluded that we no longer needed to do decolonization of patients," Schora said.
There was one final change to the program, she said. The hospital system began using an electronic protocol to identify people at high risk for MRSA carriage -- a protocol that captured 90% of carriers while only testing 50% of admissions.
To see what has happened over the 10 years from August 2005 through August 2015, she and colleagues turned to a commercially available database that tracks nosocomial infections, the Carefusion MedMined Nosocomial Infection Marker.
The database, Schora said, shows that all four hospitals now have a MRSA disease rate that is less than three cases per 10,000 patient-years, and three of the four are below two.
The researchers "showed what a lot of facilities have seen, which is a decline in their MRSA rates," commented Graham Snyder, MD, of Beth Israel Deaconess Medical Center in Boston, who co-moderated the session at which the data were presented.
"The question here is what are the interventions that have caused this trend that everyone is seeing or is it happening naturally," Snyder told MedPage Today.
Schora and colleagues, he said, "make a relatively persuasive case" that identifying colonized patients and using contact precautions were the key factors. "On the other hand, there are an increasing number of institutions that don't use contact precautions any more -- or have never used contact precautions -- and have seen declines in their MRSA rates," Snyder said.
Other factors that might have played a role, he said, are improved hand hygiene and better techniques for using catheters.
The study had no external support. Schora did not disclose any relevant relationships.
Snyder did not disclose any relevant relationships.
- Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner