What antibiotics are effective for treating folliculitis with Pseudomonas (Pseudomonas aeruginosa) coverage?

Antibiotics for Pseudomonas Folliculitis

For Pseudomonas folliculitis, ciprofloxacin 750 mg orally twice daily for 14 days is the recommended first-line treatment, as it is the only reliable oral antibiotic with consistent antipseudomonal activity. 1, 2

First-Line Oral Treatment

• Ciprofloxacin 750 mg PO twice daily for 14 days is the definitive oral choice for Pseudomonas folliculitis 1, 2, 3
• This high-dose regimen is essential because standard doses (500 mg twice daily) are insufficient for Pseudomonas infections 1
• Ciprofloxacin achieves excellent oral bioavailability matching IV levels, with sputum concentrations reaching 46-90% of serum levels 1
• The 14-day duration is standard for Pseudomonas infections, not the 7-10 days used for other pathogens 2

When to Use Intravenous or Combination Therapy

Escalate to IV therapy or combination treatment if:

• The patient is severely ill, immunocompromised, or has failed oral therapy 1, 2
• There is documented resistance or high local prevalence of multidrug-resistant Pseudomonas 1
• The patient has structural skin disease or recurrent folliculitis 1

For severe cases requiring IV therapy, use an antipseudomonal β-lactam PLUS a second agent: 1, 2

IV β-Lactam Options (choose one):

• Piperacillin-tazobactam 4.5g IV every 6 hours 1
• Ceftazidime 2g IV every 8 hours 1, 2
• Cefepime 2g IV every 8 hours 1, 2
• Meropenem 1g IV every 8 hours 1, 2

PLUS Second Agent (choose one):

• Tobramycin 5-7 mg/kg IV once daily (preferred over gentamicin due to lower nephrotoxicity) 1, 2
• Ciprofloxacin 400 mg IV every 8 hours 1

Critical Pitfalls to Avoid

• Never use ceftriaxone, cefazolin, ampicillin-sulbactam, or ertapenem - these lack antipseudomonal activity despite being broad-spectrum agents 1
• Never underdose ciprofloxacin - 500 mg twice daily is inadequate; always use 750 mg twice daily for Pseudomonas 1
• Never stop treatment at 7-10 days - this increases relapse and resistance risk; complete the full 14-day course 2
• Never extend oral ciprofloxacin monotherapy beyond 14 days - this promotes resistance without proven benefit 1
• Never assume monotherapy is adequate for severe infections - combination therapy delays resistance development 4, 1

Monitoring and Follow-Up

• Obtain culture and sensitivity testing before starting antibiotics to confirm Pseudomonas and guide therapy 1, 2
• If no clinical improvement by day 3-5, switch to IV combination therapy 1
• Monitor for resistance development, particularly when initial MIC >0.5 mg/L 5
• Obtain follow-up cultures to document eradication 2

Special Considerations

• Levofloxacin 750 mg daily is a less potent alternative to ciprofloxacin and should only be used as second-line 1, 6
• For hot tub folliculitis (Pseudomonas aeruginosa), the same treatment principles apply with prompt recognition to prevent further cases 7
• Resistance can develop during treatment in 9-30% of cases, especially with inadequate dosing or when MIC is initially elevated 8, 5
• Once susceptibility results are available and the patient is improving, de-escalation to monotherapy is appropriate if the organism is susceptible 1