What is the management of Anthrax (Bacillus anthracis infection)?

From the Guidelines

Anthrax management requires prompt treatment with antibiotics and supportive care, with ciprofloxacin 500 mg orally twice daily or doxycycline 100 mg orally twice daily for 60 days being the recommended treatment for cutaneous anthrax, as per the most recent guidelines 1. For cutaneous anthrax, the treatment duration is typically 7-10 days, but in cases of bioterrorism-related exposure, the duration is extended to 60 days to provide post-exposure prophylaxis (PEP) 2. The choice of antibiotic may depend on the severity of the disease and the presence of systemic involvement, with intravenous ciprofloxacin being recommended for severe cases 3. In cases of inhalational or gastrointestinal anthrax, combination therapy with intravenous antibiotics is necessary, with ciprofloxacin 400 mg IV every 12 hours plus one or two additional antibiotics such as meropenem 1 g IV every 8 hours and linezolid 600 mg IV every 12 hours for 60 days 4. Some key points to consider in anthrax management include:

• Early treatment is crucial to reduce mortality, particularly in cases of inhalational anthrax 5
• The long treatment duration is necessary to eliminate dormant spores that may germinate later 4
• Patients with systemic involvement require hospitalization for aggressive supportive care, including IV fluids, vasopressors if needed, and possibly mechanical ventilation 6
• Post-exposure prophylaxis following confirmed exposure is recommended, with ciprofloxacin 500 mg orally twice daily or doxycycline 100 mg orally twice daily for 60 days, along with the anthrax vaccine administered at 0, 2, and 4 weeks 2. It is essential to note that anthrax is caused by Bacillus anthracis, which produces potent exotoxins that can cause tissue damage and lead to shock and death if untreated 4.

From the FDA Drug Label

Anthrax due to Bacillus anthracis, including inhalational anthrax (post-exposure): to reduce the incidence or progression of disease following exposure to aerosolized Bacillus anthracis. Inhalational anthrax (post-exposure) 500 mg q 12 h 60 Days Inhalational Anthrax (Post-Exposure) Intravenous 10 mg/kg (maximum 400 mg per dose) Every 12 hours 60 days Oral 15 mg/kg (maximum 500 mg per dose) Every 12 hours

Anthrax Management:

• Doxycycline is indicated for the treatment of anthrax due to Bacillus anthracis, including inhalational anthrax (post-exposure) 7.
• Ciprofloxacin is indicated for the treatment of inhalational anthrax (post-exposure) in adults and pediatric patients [8] [9].
• The recommended dosage for ciprofloxacin is 500 mg every 12 hours for 60 days in adults, and 15 mg/kg (maximum 500 mg per dose) every 12 hours for 60 days in pediatric patients 9.
• The recommended dosage for ciprofloxacin IV is 10 mg/kg (maximum 400 mg per dose) every 12 hours for 60 days in pediatric patients 8.

From the Research

Anthrax Management Overview

• Anthrax is a zoonotic disease that can occur in three forms: cutaneous, gastrointestinal, and inhalation, depending on the mode of infection 10.
• The disease can be used as a biological warfare agent, and its management is crucial to prevent and treat infections.

Treatment Options

• Postexposure prophylaxis is indicated to prevent inhalational anthrax, and therapy with ciprofloxacin or doxycycline is recommended for adults and children for 60 days 10.
• Combination therapy with two or more antimicrobial agents is recommended for the treatment of inhalation anthrax, including ciprofloxacin, doxycycline, rifampicin, vancomycin, imipenem, chloramphenicol, penicillin, and ampicillin 10.
• A combination of antibiotic and immunoglobulin therapy has been shown to be more effective than antibiotic treatment alone in a rodent anthrax model 11.

Pediatric Treatment

• The Centers for Disease Control and Prevention (CDC) recommends the use of doxycycline or ciprofloxacin for prophylaxis and treatment in children, despite the limited information on the treatment of anthrax infection in children 12.
• Doxycycline is not indicated for use in children under 8 years old due to staining of teeth and inhibition of bone growth associated with tetracyclines, while ciprofloxacin has a pediatric indication only when a child is potentially exposed to inhaled anthrax 12.

Antibiotic-Resistant Strains

• The use of a strain resistant to first-line antimicrobial treatments is a concern, and combination drug therapy has been evaluated for the treatment of antibiotic-resistant inhalation anthrax in a murine model 13.
• Combination groups showed significant survival over controls, and combinations with linezolid had the greatest inhibitory effect on mean lethal factor levels 13.

Diagnosis and Control

• The symptoms of anthrax in the early stage mimic many diseases, and it is essential to confirm the diagnosis using a bacterial culture or a molecular test 14.
• Controlling anthrax in humans depends primarily on effective control of the disease in animals, and spore vaccines are used in veterinary service, while an acellular vaccine is available for humans but its use is limited 14.