Management of Staphylococcus aureus Infection in Ommaya Reservoir
Remove the Ommaya reservoir immediately and initiate systemic antibiotic therapy with vancomycin (for empiric MRSA coverage) or nafcillin/cefazolin (if methicillin-susceptible S. aureus is confirmed), continuing treatment for 14 days minimum after device removal, or 4-6 weeks if bacteremia persists beyond 72 hours or complications develop. 1, 2, 3
Device Management: Removal is Mandatory
S. aureus infections of CNS devices require complete device removal for definitive cure. 1 Unlike coagulase-negative staphylococci where salvage attempts may be reasonable, S. aureus carries a 25-32% risk of endocarditis and devastating CNS complications that preclude conservative management. 1, 2
Device removal should occur urgently, as mortality in S. aureus meningitis reaches 36-37% overall, with community-acquired infections showing even higher mortality (up to 50% in adults). 2, 3
Do not attempt catheter salvage with antibiotic lock therapy for S. aureus—this approach is only appropriate for coagulase-negative staphylococci. 1
Empiric Antibiotic Selection
Start vancomycin immediately while awaiting susceptibility results, as 48-50% of Ommaya reservoir S. aureus infections are methicillin-resistant. 2, 4
Vancomycin dosing must achieve trough concentrations of 15-20 μg/mL, as 74% of S. aureus CSF isolates demonstrate vancomycin MIC of 2 μg/mL. 5
De-escalate to nafcillin or cefazolin once methicillin-susceptible S. aureus (MSSA) is confirmed, as only one patient receiving initial penicillinase-resistant penicillin died in historical series, versus six of 12 patients not receiving appropriate beta-lactam therapy. 3
Adjunctive Antibiotic Therapy
Add rifampin or trimethoprim-sulfamethoxazole to vancomycin in severe cases, particularly for community-acquired MRSA infections or patients with altered mental status, septic shock, or concurrent bacteremia. 2, 4
Rifampin must always be combined with a second agent to prevent resistance emergence. 6
Linezolid represents an alternative option due to excellent CSF penetration, though clinical experience is limited to case reports. 2, 4
Treatment Duration
Minimum 14 days of systemic antibiotics after device removal for uncomplicated infection with clinical response. 1, 2
Extend to 4-6 weeks if:
Mean treatment duration in published series is 17 days (range 1-42 days), though this reflects variable clinical scenarios. 2
Diagnostic Workup
Obtain blood cultures from both peripheral vein and device (if still in place) before initiating antibiotics. 1, 4
Perform transesophageal echocardiography (TEE) at 5-7 days after bacteremia onset unless blood cultures and clinical assessment are negative at 72 hours post-removal, given the 25-32% endocarditis risk. 1
Monitor for concurrent staphylococcal infections outside the CNS, as 64% of hematogenous S. aureus meningitis cases have identifiable foci elsewhere, and nine of 11 such patients died in one series. 2, 3
Critical Pitfalls to Avoid
Do not use cefazolin for empiric treatment before susceptibility results, as it lacks MRSA coverage and 48-50% of infections are methicillin-resistant. 2
Do not attempt device salvage—S. aureus CNS device infections require removal, unlike coagulase-negative staphylococcal infections where retention may be attempted. 1
Do not underdose vancomycin—ensure troughs of 15-20 μg/mL given the high MIC values of contemporary S. aureus isolates. 5
Be aware that hematogenous S. aureus meningitis (versus postoperative) is associated with injection drug use, underlying disease, altered mental status, fever, septic shock, and bacteremia—all markers of more severe disease requiring aggressive management. 2