Risk of MRSA Infection in Patients with Intermittent versus Persistent MRSA Nares Colonization.

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Risk of MRSA Infection in Patients with Intermittent versus Persistent MRSA Nares Colonization.

Infect Control Hosp Epidemiol. 2015 Aug 20;:1-6

Authors: Vigil DI, Harden WD, Hines AE, Hosokawa PW, Henderson WG, Bessesen MT

Abstract
OBJECTIVE To determine the relative risk of invasive methicillin-resistant Staphylococcus aureus (MRSA) infection among non-colonized (NC) patients, intermittently colonized (IC) patients, and persistently colonized (PC) patients. DESIGN Observational cohort study of patient data collected longitudinally over a 41-month period. SETTING Department of Veterans Affairs Eastern Colorado Healthcare System, a tertiary care medical center. PATIENTS Any patient who received ≥5 MRSA nasal swab tests between February 20, 2010, and July 26, 2013. In total, 3,872 patients met these criteria, 0 were excluded, 95% were male, 71% were white, and the mean age was 62.9 years on the date of study entry. METHODS Patients were divided into cohorts based on MRSA colonization status. Physicians reviewed medical records to identify invasive infection and were blinded to colonization status. Cox and Kaplan-Meier analyses were used to assess the relationship between colonization status and invasive infection. RESULTS In total, 102 patients developed invasive MRSA infections, 16.3% of these were PC patients, 11.2% of these were IC patients, and 0.5% of these were NC patients. PC patients were at higher risk of invasive infection than NC patients (hazard ratio [HR] 36.8; 95% CI, 18.4-73.6; P<.001). IC patients were also at higher risk than NC patients (HR, 22.8; 95% CI, 13.3-39.3; P<.001). The difference in risk between PC and IC patients was not statistically significant (HR, 1.61; 95% CI, 0.94-2.78, P=.084). Alternate analysis methods confirmed these results. CONCLUSIONS The risk of invasive MRSA infection is much higher among PC and IC patients, supporting routine clinical testing for colonization. However, this risk is similar among PC and IC patients, suggesting that distinguishing between the 2 colonization states may not be clinically important. Infect. Control Hosp. Epidemiol. 2015;00(0):1-6.

PMID: 26289065 [PubMed - as supplied by publisher]