What are the recommended antibiotics for treating plague (bubonic, septicemic, or pneumonic) in adults?

Antibiotics to Treat Plague in Adults (bubonic, septicemic, pneumonic)

Bolded Recommendation

• Start a fluoroquinolone (preferred: levofloxacin 750 mg IV/PO q24h or ciprofloxacin 400 mg IV q8h or 750 mg PO q12h) immediately for 10–14 days; add a second class up front only for severe pneumonic/septicemic disease, then de-escalate to monotherapy once stable. 1

Step-by-step algorithm (prioritizing mortality/morbidity/QOL)

1. Classify severity and form

• Severe disease or high-risk: respiratory failure/shock, rapidly progressive pneumonia or sepsis, meningitis concern → treat as severe pneumonic/septicemic.
• Otherwise: treat as uncomplicated bubonic or stable pharyngeal plague. 1

1. Immediate empiric therapy (do not delay)

• First-line options (choose ONE for most adults; all IV or PO per stability, for 10–14 days):

  • Levofloxacin 750 mg q24h IV/PO
  • Ciprofloxacin 400 mg IV q8h or 750 mg PO q12h
  • Moxifloxacin 400 mg q24h IV/PO
  • Doxycycline 200 mg load, then 100 mg q12h IV/PO
  • Gentamicin 5 mg/kg q24h IV/IM
  • Streptomycin 1 g q12h IV/IM (availability limited) 1

• If severe pneumonic or septicemic disease: start dual therapy with two distinct classes (e.g., levofloxacin + gentamicin) initially, then narrow to monotherapy once improving. 1

1. Duration and route

• Treat 10–14 days; switch IV→PO once clinically stable and able to absorb. All recommended orals can be given via enteral tube except ciprofloxacin. 1

1. Alternatives if contraindications/intolerance

• Chloramphenicol 12.5–25 mg/kg q6h IV (monitor levels, use lower end in most; consider for meningitis because of CNS penetration)
• Ofloxacin 400 mg q12h PO
• Gemifloxacin 320 mg q24h PO
• Amikacin 15–20 mg/kg q24h IV/IM
• Tobramycin 5–7 mg/kg q24h IV/IM
• Plazomicin 15 mg/kg q24h IV
• Tetracycline 500 mg q6h PO
• Minocycline 200 mg load, then 100 mg q12h IV/PO
• TMP-SMX 5 mg/kg (TMP) q8h IV/PO 1

Rationale and evidence strength

• 2021 CDC MMWR guideline is the most recent, highest-quality directive; it endorses fluoroquinolones, tetracyclines, and aminoglycosides as first line; dual therapy only for severe pneumonic/septicemic cases or intentional release. This directly targets mortality reduction in the most lethal forms. 1
• Systematic review of 762 cases shows low fatality with tetracyclines and fluoroquinolones comparable to aminoglycosides, supporting efficacy and safety; no clear benefit of combination over monotherapy in typical cases. 2
• Preclinical work supports fluoroquinolone potency for pneumonic plague. 1

Practical pearls and pitfalls

• Do not delay antibiotics for diagnostics; early therapy is critical to prevent death, especially in pneumonic/septicemic forms. 1
• Add a second class initially only in severe pneumonic/septicemic disease; otherwise monotherapy is standard (minimizes toxicity and preserves QOL). 1
• Avoid ciprofloxacin in enteral-tube administration (binding/absorption issues); use levofloxacin or moxifloxacin if enteral needed. 1
• Consider chloramphenicol if meningitis suspected due to CNS penetration, but monitor for toxicity; use lowest effective dose. 1
• Streptomycin availability is limited; gentamicin or fluoroquinolone are practical first-line choices. Monitor aminoglycosides for nephro/ototoxicity. 1
• Treat 10–14 days consistently; extend only if complications persist. 1