February 15, 2019
2 min read

Re-exposure to antibiotics increases risk for VRE recolonization

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Findings from a retrospective cohort study showed that colonization with vancomycin-resistant Enterococcus, or VRE, is significantly associated with VRE infection and increased mortality, and that re-exposure to antibiotics increases the risk for VRE recolonization, researchers reported in Infection Control & Hospital Epidemiology.

“Factors contributing to colonization with VRE include prolonged hospital stay, immunosuppression, hematologic malignancy, residence in long-term care facilities, invasive procedures, proximity to colonized or infected patients, occupying a room vacated by a VRE-colonized patient, and use of third-generation cephalosporins, intravenous vancomycin or anti-anaerobic antibiotics,” Heather Y. Hughes, MD, clinical assistant professor at the Medical University of South Carolina and a hospital epidemiologist for the Ralph H. Johnson VA Medical Center, and colleagues wrote. “Whether the same risk factors that promote initial colonization also encourage recolonization with VRE is not well understood.”

For their study, Hughes and colleagues assessed the dynamics of VRE colonization among patients with VRE infection or colonization identified from active surveillance or clinical cultures between January 2007 and December 2015 at the NIH Clinical Center.

According to the published study, they reviewed charts to collect baseline characteristics, and used a survival analysis to determine the relationship between antibiotic exposure and time to VRE recolonization in a subcohort of patients. They calculated antibiotic exposure and hospital days as proportions of VRE decolonized days.

Overall, 350 patients were either infected or colonized with VRE, Hughes and colleagues reported. PCR had a 39% positive predictive value for colonization among PCR-positive, culture negative patients. According to the study, colonization with VRE was significantly associated with VRE infection.

Among the subcohort of 72 patients who met the decolonization criterion — defined as having three consecutive perirectal swabs return negative for VRE — 29% became recolonized. Hughes and colleagues calculated that VRE colonization was 4.3 times higher in patients whose percentage of total antibiotic days was above the cohort median and 2 times higher among patients with proportions of antianaerobic antibiotic days above the median (P = .22).

“VRE colonization is tenacious and increases the likelihood of VRE infection in immunocompromised patients,” Hughes and colleagues concluded. “We have shown that higher total antibiotic days as a proportion of VRE decolonized days is associated with shorter time to VRE recolonization. VRE decolonization is a fragile state during which monitoring antimicrobial usage metrics could aid in screening and isolation decisions among patients who appear to have become decolonized.” – by Marley Ghizzone

Disclosures: Hughes reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.