Estimated Methicillin-Resistant Staphylococcus aureus Decolonization in Intensive Care Units Associated With Single-Application Chlorhexidine Gluconate or Mupirocin

Abstract

This mathematical modeling study estimates the decolonization of methicillin-resistant Staphylococcus aureus (MRSA) associated with chlorhexidine gluconate and mupirocin in a simulated intensive care unit (ICU).

Key Points

Question

What is the estimated proportion of patients with methicillin-resistant Staphylococcus aureus (MRSA) decolonized per application of chlorhexidine and mupirocin?

Findings

This mathematical modeling study estimated that chlorhexidine and mupirocin were independently associated with a 15% likelihood of decolonization in patients with MRSA.

Meaning

This study found that, on a per-application basis, chlorhexidine and mupirocin were associated with decolonization; this suggests that there may be room for improvement and innovation in MRSA decolonization interventions.

Abstract

Importance

Chlorhexidine gluconate (CHG) and mupirocin are widely used to decolonize patients with methicillin-resistant Staphylococcus aureus (MRSA) and reduce risks associated with infection in hospitalized populations. Quantifying the association of an application of CHG alone or in combination with mupirocin with risk of MRSA infection is important for studies evaluating alternative decolonization strategies or schedules and for identifying whether there is room for improved decolonizing agents.

Objective

To estimate the proportion of patients with MRSA decolonized per application of CHG and mupirocin from existing population-level studies.

Design, Setting, and Participants

A stochastic mathematical model of an 18-bed intensive care unit (ICU) in an academic medical center operating over 1 year was used to estimate parameters for the proportion of simulated patients with MRSA decolonized per application of CHG and mupirocin. The model was conducted using approximate bayesian computation with data from an existing meta-analysis of studies conducted from February 2005 through January 2015. Data were analyzed from January 2018 through November 2019.

Exposure

A universal decolonization protocol for colonized patients in the ICU using CHG or CHG and mupirocin in combination was simulated.

Main Outcomes and Measures

The proportion of patients with MRSA decolonized per application of CHG and mupirocin was estimated.

Results

The estimated proportion of patients with MRSA decolonized per application of CHG was 0.15 (95% credible interval, 0.01-0.42), and the estimated proportion per application of mupirocin in conjunction with CHG was 0.15 (95% credible interval, 0.01-0.54). A lag in colonization detection was associated with decreases in the CHG estimate (0.11; 95% credible interval, 0.01-0.30) and mupirocin estimate (0.10; 95% credible interval, 0.00-0.34), which were sensitive to the value of the modeled contact rate between nurses and patients. A 1% increase in the value of this parameter was associated with a 0.73% increase in the estimated combined outcomes associated with CHG and mupirocin (95% CI: 0.71, 0.75). Gaps longer than 24 hours in the administration of decolonizing agents were associated with a decrease of within-ICU MRSA transmission. Compared with a mean (SD) of 1.23 (0.27) acquisitions per 1000 patient-days in scenarios with no decolonizing bathing, a bathing protocol administering CHG and mupirocin every 120 hours was associated with a mean (SD) acquisition rate of 1.03 (0.24) acquisitions per 1000 patient days, a 16.3% decrease (95% CI, 14.7%-18.0%; P > .001).

Conclusions and Relevance

These findings suggest that there may be room for significant improvement in anti-MRSA disinfectants, including the compounds themselves and their delivery mechanisms. Despite the decolonization estimates found in this study, these agents are associated with robust outcomes after delays in administration, which may help in alleviating concerns over patient comfort and toxic effects.