Positivity of repeat nasal MRSA PCR screening: a single-center experience

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Healthcare Epidemiology

Background:

• Nasal methicillin-resistant Staphylococcus aureus (MRSA) colonization is a significant concern in healthcare settings.
• Repeat screening for MRSA using polymerase chain reaction (PCR) is common practice.
• The clinical utility and cost-effectiveness of serial MRSA PCR testing within a single admission are debated.

Purpose of the Study:

• To evaluate the frequency of conversion from negative to positive nasal MRSA PCR results within a 14-day period during a single inpatient admission.
• To assess the potential impact of repeat MRSA PCR testing on healthcare costs and antibiotic stewardship.
• To determine if repeat MRSA screening provides additional benefit beyond initial testing.

Main Methods:

• Retrospective, single-center study design.
• Analysis of inpatient data including serial nasal MRSA PCR results within 14 days.
• Calculation of the conversion rate from negative to positive MRSA PCR results.

Main Results:

• Conversion from a negative to a positive nasal MRSA PCR result during a single inpatient admission was uncommon.
• The observed conversion rate was 2% in the evaluated patient cohort.
• This low conversion rate suggests limited benefit from repeat MRSA PCR testing within this timeframe.

Conclusions:

• Repeat nasal MRSA PCR testing within 14 days of initial screening during an inpatient admission is infrequently associated with a change in MRSA status.
• The low conversion rate questions the routine use and cost-effectiveness of serial MRSA PCR screening in this context.
• Findings support a re-evaluation of current guidelines regarding repeat MRSA PCR testing to optimize resource utilization and antibiotic stewardship.