Targeted Surveillance of Methicillin-Resistant Staphylococcus aureus and Its Potential Use To Guide Empiric Antibiotic Therapy

Abstract

The present study aimed to determine the frequency of methicillin-resistant Staphylococcus aureus (MRSA)-positive clinical culture among hospitalized adults in different risk categories of a targeted MRSA active surveillance screening program and to assess the utility of screening in guiding empiric antibiotic therapy. We completed a prospective cohort study in which all adults admitted to non-intensive-care-unit locations who had no history of MRSA colonization or infection received targeted screening for MRSA colonization upon hospital admission. Anterior nares swab specimens were obtained from all high-risk patients, defined as those who self-reported admission to a health care facility within the previous 12 months or who had an active skin infection on admission. Data were analyzed for the subcohort of patients in whom an infection was suspected, determined by (i) receipt of antibiotics within 48 h of admission and/or (ii) the result of culture of a sample for clinical analysis (clinical culture) obtained within 48 h of admission. Overall, 29,978 patients were screened and 12,080 patients had suspected infections. A total of 46.4% were deemed to be at high risk on the basis of the definition presented above, and 11.1% of these were MRSA screening positive (colonized). Among the screening-positive patients, 23.8% had a sample positive for MRSA by clinical culture. Only 2.4% of patients deemed to be at high risk but found to be screening negative had a sample positive for MRSA by clinical culture, and 1.6% of patients deemed to be at low risk had a sample positive for MRSA by clinical culture. The risk of MRSA infection was far higher in those who were deemed to be at high risk and who were surveillance culture positive. Targeted MRSA active surveillance may be beneficial in guiding empiric anti-MRSA therapy.

Predictive Value of Methicillin-Resistant Staphylococcus aureus (MRSA) Nasal Swab PCR Assay for MRSA Pneumonia

“…Although multiple studies have attempted to determine the utility of the MRSA nasal swab for predicting MRSA infection, significant heterogeneity exists with regard to the use of PCR versus chromogenic culture medium, body site sampled for colonization, and timing (8,11,12,39,40). The two largest of these studies, a retrospective review by Robicsek et al (11) and a prospective analysis by Harris et al (8), both suggest that the nasal MRSA PCR (GeneOhm; Becton, Dickinson and Company) demonstrates a modest PPV but an NPV greater than 98% for MRSA infection at any body site.…”

“…However, in many cases, cultures are negative and clinicians must determine in whom antibiotics can be safely de-escalated. S. aureus, including MRSA, colonizes the nares (2-6), and colonization has been shown to be a predictor of future clinical infection (7)(8)(9)(10)(11)(12). MRSA nasal colonization can be accurately detected using the nasal swab PCR test (13,14).…”

Utility of prior screening for methicillin-resistant Staphylococcus aureus in predicting resistance of S. aureus infections

“…Few studies to date have examined the predictive value of screening for MRSA. Most were limited to swabs obtained either on admission 23 or within 24 hours of a clinical infection, and included all clinical infections. 19 Strymish and colleagues 24 studied the utility of prior screening in predicting the results of preoperative screening for MRSA, and found a similar specificity to that found to our study.…”

Hospital Discharge Instructions: Comprehension and Compliance Among Older Adults

“…21 Data in the CDR have been validated against patients' paper medical charts and have demonstrated predictive values exceeding 99 %. 22,23 To determine whether home medications were continued, we abstracted medication information from patient discharge summaries.…”