What is the recommended treatment for Staphylococcus lugdunensis infections?

Treatment of Staphylococcus lugdunensis Infections

Staphylococcus lugdunensis should be treated with beta-lactam antibiotics (oxacillin, cloxacillin, or cefazolin) as first-line therapy, as this organism remains highly susceptible to these agents and outcomes are superior compared to vancomycin. 1, 2

Key Clinical Recognition

S. lugdunensis is a coagulase-negative staphylococcus that behaves more like S. aureus than other CoNS, causing aggressive infections with higher morbidity and mortality. 3, 4 This organism is always methicillin-susceptible and should be treated accordingly. 1

Antibiotic Selection by Clinical Syndrome

Skin and Soft Tissue Infections (SSTI)

Outpatient Management:

• Oxacillin or cloxacillin are preferred for oral therapy 5, 4
• Penicillin G may be superior to oxacillin based on MIC data (MIC50 and MIC90 values threefold lower for penicillin G) 5
• Cefazolin is an effective alternative first-generation cephalosporin 6
• Duration: 5-21 days depending on severity and clinical response 4

Inpatient Management (complicated SSTI):

• Cefazolin or oxacillin IV as first-line 1, 4
• Duration: 7-14 days based on clinical response 1
• Surgical drainage should be performed for abscesses 4

Infective Endocarditis

S. lugdunensis endocarditis is particularly aggressive, presenting with valve destruction, abscess formation, and high mortality rates requiring urgent intervention. 1, 3, 7

Antibiotic Regimen:

• Cloxacillin or oxacillin 12 g/day IV in 4-6 divided doses for 4-6 weeks 1
• Alternative: Cefazolin at equivalent dosing 1
• For prosthetic valve endocarditis: Add rifampin 300 mg PO q8h after 3-5 days once bacteremia is cleared 1
• Do NOT add aminoglycosides to beta-lactam therapy for native valve endocarditis due to increased renal toxicity without benefit 1

Surgical Considerations:

• Early cardiac surgery is often required (approximately 50% of cases) due to valve destruction 1, 7
• Delayed surgery or antibiotic therapy alone frequently results in fatal outcomes 7
• Urgent surgical consultation should be obtained at diagnosis 7

Prosthetic Joint Infections

Beta-lactam antibiotics demonstrate superior outcomes compared to vancomycin for S. lugdunensis prosthetic joint infections. 2

Treatment Approach:

• Parenteral beta-lactam (oxacillin or cefazolin) for median 38 days 2
• Freedom from treatment failure at 2 years: 92% with beta-lactams vs. 76% with vancomycin (P=0.015) 2
• Surgical debridement or prosthesis removal typically required 3, 2

When to Avoid Vancomycin

Vancomycin should NOT be used for S. lugdunensis when beta-lactams are an option, as vancomycin is inferior to beta-lactam therapy. 1, 2 Reserve vancomycin only for patients with true type 1 hypersensitivity reactions to penicillins where desensitization is not feasible. 1

Antimicrobial Susceptibility Profile

• Penicillin susceptibility: 74.6% of isolates in recent studies 5
• Methicillin resistance: rare (mecA carriage <5%) 5, 2
• Among 28 prosthetic joint infection isolates, 86% were oxacillin-susceptible and 95% lacked mecA 2
• Beta-lactamase production occurs in approximately 27% of isolates 2
• Remains susceptible to most antibiotics including clindamycin, trimethoprim-sulfamethoxazole, and fluoroquinolones 5, 4

Critical Pitfalls to Avoid

• Do not treat S. lugdunensis like other coagulase-negative staphylococci - it requires aggressive therapy similar to S. aureus 3, 4
• Do not use vancomycin empirically when beta-lactams can be used - outcomes are significantly worse 1, 2
• Do not delay cardiac surgery in endocarditis cases - early intervention is critical for survival 7
• Do not add rifampin as monotherapy or with vancomycin for SSTI - it provides no benefit and risks resistance 1
• Ensure microbiology laboratories identify coagulase-negative staphylococci to species level, as S. lugdunensis may be underrecognized 4

Special Populations

Patients with urogenital abnormalities: 32% of prosthetic joint infection patients had underlying urogenital pathology, suggesting a potential source for bacteremia 2

Patients with chronic skin conditions: 75% of SSTI cases were secondary to trauma, surgery, or pre-existing skin disease 4