The researchers said that the MRSA infection rate decreased from 1.9 to 1.4 patients per 100 admissions in the surgical ICU when they switched between two antibiotics, linezolid and vancomycin, every three months.
In their study report, published in the journal Surgical Infections, the researchers have also revealed that in-hospital mortality from surgical ICU-acquired MRSA infections fell from 3.8 patients per year to none.
The report suggests that study data spanned six years, including the period before cycling began (1997 to 2001) and the period after it was instituted (2002 to 2003).
It also reveals that the study's key focus was resistant gram-positive cocci, a subgroup defined as MRSA (methicillin-resistant Staphylococcus aureus) and VRE (vancomycin-resistant Enterococcus).
"Before we began cycling, 67 percent of the Staphylococcus aureus infections in our surgical ICU were caused by MRSA. Cycling reduced MRSA cases to 36 percent of that total," says the lead author of the study, Dr. Robert Sawyer, a professor of surgery and co-director of UVA's Surgical Trauma Intensive Care Unit.
The researchers claim that their study is the first to assess the impact of antibiotic cycling on a group of bacteria known as gram-positive cocci.
Dr. Sawyer says that though the findings are important, they need to be confirmed by similar studies in other ICU's.
"If cycling proves effective at other centers, we might be able to turn the tide on antibiotic resistance, at least for MRSA. In the long run, reducing MRSA should decrease the number of deaths among critically ill patients. However, the problem is very complex and will almost certainly need a variety of interventions to achieve the best outcomes," he says.
While MRSA infection rates fell during cycling, the prevalence of VRE remained virtually unaltered.
According to the researchers, VRE infection rates rose slightly, from .76 to .98 patients per 100 admissions. In-hospital mortality from VRE dropped from 2.8 to 2.5 patients per year.
Cycling reduced the surgical ICU's overall gram-positive infection rate from 19.6 to 11.8 patients per 100 admissions, and lowered the rate of infections from resistant gram-positive cocci from 4.6 to 1.7 patients per 100 admissions.