Overview
Definition:
Pre-operative nasal decolonization refers to the targeted eradication of Staphylococcus aureus (including Methicillin-resistant Staphylococcus aureus - MRSA) carriage from the anterior nares of patients undergoing surgery
This aims to reduce the risk of surgical site infections (SSIs) caused by the patient's own bacteria.
Epidemiology:
Approximately 30% of the general population are persistent nasal carriers of S
aureus
These carriers are at a significantly higher risk of developing SSIs, especially in orthopedic, cardiac, and neurosurgical procedures
MRSA carriage is a major concern due to its antibiotic resistance.
Clinical Significance:
S
aureus is a leading cause of SSIs
Eliminating nasal carriage pre-operatively is a critical strategy for reducing SSI rates, thereby improving patient outcomes, decreasing hospital stays, and lowering healthcare costs
It is a fundamental component of enhanced recovery after surgery (ERAS) protocols.
Indications
Routine Screening:
Current guidelines recommend screening for S
aureus (including MRSA) in patients undergoing specific types of surgery, particularly those with a high risk of SSIs and implant placement.
High Risk Procedures:
Procedures such as orthopedic surgery (joint replacements, spinal surgery), cardiac surgery, neurosurgery, and procedures involving prosthetic material have higher rates of S
aureus related SSIs.
Known Carrier Status:
Patients identified as S
aureus carriers through screening protocols, especially MRSA carriers.
Previous Ssi:
Patients with a history of SSIs attributed to S
aureus may benefit from decolonization.
Diagnostic Approach
Screening Methods:
Nasal swabs are typically collected from the anterior nares and cultured for S
aureus
Rapid molecular assays can also detect S
aureus and MRSA, providing quicker results.
Culture And Sensitivity:
Standard culture methods identify S
aureus and allow for antibiotic susceptibility testing
This is crucial for determining the appropriate decolonization agent and for identifying MRSA.
Interpreting Results:
Positive cultures for S
aureus (MSSA or MRSA) warrant consideration for nasal decolonization
Screening negative patients may still benefit from empiric decolonization in very high-risk settings, though evidence is less robust.
Management
Pharmacological Decolonization:
The primary agents used are topical intranasal antibiotics
Mupirocin ointment (2% twice daily for 5 days) is the gold standard for MSSA and MRSA decolonization
Alternatively, retapamulin ointment can be used.
Alternative Agents:
For patients allergic to mupirocin or in specific scenarios, dilute bleach (0.05% sodium hypochlorite) nasal irrigation or antiseptic washes (e.g., chlorhexidine) may be considered, though evidence for efficacy in eradicating nasal carriage is less consistent than for mupirocin.
Systemic Antibiotics:
Systemic antibiotics are generally NOT recommended for nasal decolonization alone, but may be co-administered as part of surgical prophylaxis or treatment of established infection.
Duration Of Treatment:
A standard course of intranasal mupirocin is typically 5 days, administered twice daily
Compliance is crucial for efficacy.
Timing Of Treatment:
Nasal decolonization should ideally be initiated within 5-7 days prior to the scheduled surgical procedure to allow sufficient time for eradication and minimize recolonization.
Post Decolonization Strategies
Re Screening:
Re-screening for nasal carriage after decolonization is generally not recommended for MSSA
For MRSA, some protocols advocate for re-screening a week after treatment completion to confirm eradication, especially for very high-risk procedures.
Surgical Prophylaxis:
Even after successful decolonization, appropriate perioperative antibiotic prophylaxis covering S
aureus should still be administered according to institutional guidelines.
Infection Prevention Measures:
Continued adherence to strict sterile techniques, hand hygiene, and environmental cleaning remains paramount to prevent SSIs, regardless of decolonization status.
Complications
Resistance Development:
A significant concern with prolonged or inappropriate use of topical antibiotics is the development of antimicrobial resistance, particularly with mupirocin
This underscores the importance of judicious use and adherence to prescribed durations.
Allergic Reactions:
Rarely, patients may develop local or systemic allergic reactions to intranasal agents.
Recolonization:
Despite successful decolonization, patients can become re-colonized from environmental sources or other body sites
The risk of recolonization within the perioperative period needs to be considered.
Treatment Failure:
Incomplete eradication may occur due to poor compliance, incorrect application, or bacterial resistance
This can lead to continued risk of SSI.
Key Points
Exam Focus:
Understanding the prevalence of nasal carriage, the link to SSIs, and the role of topical intranasal antibiotics (especially mupirocin) is critical
Know the indications, duration, and timing of treatment
DNB/NEET SS often tests knowledge of SSI prevention strategies.
Clinical Pearls:
Emphasize patient education on correct application technique for nasal ointments
Ensure a 5-day course is completed before surgery
Consider MRSA status for high-risk patients
Collaborate with microbiology for resistance patterns.
Common Mistakes:
Prescribing systemic antibiotics for decolonization
Failing to complete the full course of topical treatment
Not screening for MRSA in appropriate patient groups
Forgetting perioperative antibiotic prophylaxis even after decolonization.