From the Guidelines
MRSA nares PCR testing is proven effective in patients with cancer, particularly those with a history of MRSA infection, hospitalization, or exposure to healthcare facilities within the preceding year, as well as those with select comorbid conditions such as immunosuppression, diabetes, chronic obstructive pulmonary disease, congestive heart failure, and use of hemodialysis. This population is at increased risk of MRSA colonization and subsequent infection, and the use of nares PCR testing can help identify colonized patients and guide targeted decolonization protocols and infection control measures 1. The test is particularly useful in surgical patients, where a positive nasal MRSA PCR screen has been found to increase the odds of a subsequent MRSA surgical site infection (SSI) by 2-fold to 14-fold compared to patients with negative screens. Key factors that increase the likelihood of MRSA colonization in this population include:
- Prior history of MRSA infection
- Hospitalization and exposure to healthcare facilities within the preceding year
- Receipt of antibiotics within 3 months before admission
- Presence of select comorbid conditions, such as immunosuppression, diabetes, chronic obstructive pulmonary disease, congestive heart failure, and use of hemodialysis. The use of MRSA nares PCR testing in this population can help reduce the risk of postoperative gram-positive infections, especially when combined with decolonization protocols and intravenous vancomycin prophylaxis 1.
From the Research
Population for MRSA Nares PCR Testing
The population for MRSA (Methicillin-resistant Staphylococcus aureus) nares PCR (Polymerase Chain Reaction) testing includes:
- Hospitalized patients with MRSA colonization or infection 2
- Patients undergoing surgical procedures, particularly those at high risk for surgical site infections (SSIs) 3
- Patients with community-acquired infections 4
- Patients colonized with MRSA who are at high risk for infection, such as those undergoing total joint replacement 3
- Hospitalized patients who are colonized with MRSA and are at risk for postdischarge infection 5
Key Findings
- MRSA nares PCR testing has been shown to be effective in detecting MRSA colonization in various populations 4, 6, 2
- The use of mupirocin nasal ointment and chlorhexidine mouthwash and baths or showers has been shown to be effective in decolonizing MRSA carriers 2, 5
- Decolonization with chlorhexidine and mupirocin has been shown to reduce the risk of MRSA infection and hospitalization due to MRSA infection 5
Study Populations
- A study published in 2008 found that a standardized regimen for MRSA decolonization was highly effective in patients who completed the full decolonization treatment course, with a success rate of 87% 2
- A study published in 2019 found that postdischarge MRSA decolonization with chlorhexidine and mupirocin led to a 30% lower risk of MRSA infection than education alone 5
- A study published in 2020 found that intranasal mupirocin prior to MRSA PCR screening may reduce the negative predictive value of the screen 6