What is the role of nafcillin (Nafcillin) in treating pediatric gram-positive cocci skin abscesses?

Nafcillin for Pediatric Gram-Positive Cocci Skin Abscesses

Nafcillin is an appropriate antibiotic for treating recurrent skin abscesses in children when methicillin-susceptible Staphylococcus aureus (MSSA) is confirmed or strongly suspected, but it is NOT the first-line treatment for simple abscesses, which should be managed primarily with incision and drainage alone. 1

Primary Management: Drainage Over Antibiotics

• Simple skin abscesses in children should be treated with incision and drainage alone, without routine antibiotic therapy. 1
• Incision and drainage without adjunctive antibiotics is effective for community-acquired abscesses <5 cm in diameter in immunocompetent children. 2
• Antibiotics are not routinely recommended for simple abscesses or boils after adequate drainage. 1

When Nafcillin Is Indicated

Nafcillin becomes appropriate in specific clinical scenarios:

• Recurrent abscesses: After obtaining cultures, treat with nafcillin 50 mg/kg/dose IV every 4-6 hours (pediatric dosing) for a 5- to 10-day course if MSSA is isolated. 1
• Severe or complicated infections: When systemic signs are present (fever, hypotension, oliguria, altered mental status) or in immunocompromised patients. 1
• Failed drainage alone: When incision and drainage has not resulted in clinical improvement. 1

Critical Decision Point: MRSA vs MSSA

The choice between nafcillin and alternative agents hinges on methicillin resistance:

• If MRSA is suspected or confirmed: Nafcillin is ineffective. Use vancomycin (15 mg/kg/dose IV every 6 hours), clindamycin (if local resistance <10%), or linezolid (10 mg/kg/dose every 8-12 hours depending on age). 1, 3, 4
• If MSSA is confirmed: Nafcillin or cefazolin are appropriate beta-lactam options. 1, 5
• Empiric therapy considerations: In communities with high MRSA prevalence (>10-15%), or in patients with risk factors (recent hospitalization, prior MRSA, injection drug use), empiric MRSA coverage is warranted rather than nafcillin. 1

Alternative Agents for MSSA

When nafcillin is not available or appropriate:

• Cefazolin 33 mg/kg/dose IV every 8 hours is an effective alternative for MSSA with similar efficacy. 1
• Oral step-down options include cephalexin 500 mg every 6 hours (adult) or flucloxacillin for less severe infections. 1, 5

Common Pitfalls to Avoid

• Do not use nafcillin empirically without considering local MRSA prevalence—rates of MRSA in skin infections vary widely (22.5% overall in European surveillance, but with significant regional variation). 6
• Do not prescribe antibiotics for simple abscesses <5 cm that can be adequately drained—this leads to unnecessary antibiotic exposure and resistance. 2
• Do not assume penicillin allergy requires vancomycin—cefazolin can be used if the allergy is not type 1 hypersensitivity. 3
• Obtain cultures before starting antibiotics in recurrent abscesses to guide targeted therapy and avoid empiric broad-spectrum coverage. 1

Duration and Monitoring

• Treatment duration is typically 7-14 days depending on clinical response, with most cases requiring 7 days. 1, 3
• Consider decolonization strategies (intranasal mupirocin, chlorhexidine washes) for recurrent S. aureus infections after completing antibiotic therapy. 1