From the Guidelines
If your nares test positive for MRSA, it means you are at a higher risk of developing a MRSA infection and potentially spreading it to others, especially if you have a history of hospitalization, exposure to healthcare facilities, or certain comorbid conditions, as noted in a 2023 study 1. This doesn't necessarily mean you have an active infection, but rather that you're carrying the bacteria. MRSA colonization can increase your risk of developing a MRSA infection, particularly surgical site infections, as surgical patients with positive nasal MRSA screens have been found to have 2-fold to 14-fold greater odds of a subsequent MRSA infection 1. Some key points to consider include:
- The likelihood of MRSA colonization increases with prior history of MRSA infection, hospitalization, and exposure to healthcare facilities within the preceding year, as well as receipt of antibiotics within 3 months before admission 1
- Treatment typically involves applying mupirocin ointment (Bactroban) inside both nostrils, and using chlorhexidine soap for bathing, as part of a bundled approach to decrease the rate of postoperative gram-positive infections 1
- Good hygiene practices are essential, including washing hands frequently, not sharing personal items, and keeping any wounds clean and covered
- Healthcare providers should be informed about your MRSA status before procedures or hospital stays It's also important to note that MRSA colonization can sometimes resolve on its own or with treatment, but may recur, especially in healthcare workers or those with frequent hospital exposure. A study from 2005 1 discussed the importance of controlling recurrent furunculosis, which can be caused by MRSA, through the use of antibacterial agents to eradicate staphylococcal carriage. However, the most recent and highest quality study 1 prioritizes a bundled approach including decolonization protocols and intravenous vancomycin prophylaxis to decrease the rate of postoperative gram-positive infections.
From the Research
Definition of MRSA and Nares Positivity
- MRSA stands for Methicillin-resistant Staphylococcus aureus, a type of bacteria that is resistant to many antibiotics 2, 3, 4, 5, 6.
- A positive nares culture for MRSA means that the bacteria has been detected in the nasal passages of an individual 4.
Risk Factors for MRSA Colonization
- Risk factors for MRSA colonization include:
- These risk factors can increase the likelihood of MRSA colonization, and limiting surveillance cultures to patients with one or more of these risk factors may allow for targeted screening 4.
Treatment and Elimination of MRSA Carriage
- Vancomycin remains a drug of choice for treating MRSA infections, but it has limitations such as nephrotoxicity and rapid target attainment 2, 3, 5, 6.
- Mupirocin is an effective topical agent for eliminating MRSA colonization, but its use is limited to nasal carriage and has variable success in eradicating colonization in patients who carry the organism at multiple body sites 2, 5.
- Newer anti-MRSA antibiotics such as linezolid, daptomycin, and ceftaroline have been approved and are recommended as co-first-line options in clinical practice guidelines 3, 6.
Implications of MRSA Nares Positivity
- A positive nares culture for MRSA can indicate colonization, which can increase the risk of infection and transmission to others 2, 4.
- Eradicating MRSA nasal colonization can be challenging, and requires a comprehensive approach that includes infection control measures, hand hygiene, and targeted screening 2, 4.