Bacillus anthracis: Difference between revisions
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Bacillus anthracis
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==Background== |
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* Causes '''anthrax''' |
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===Microbiology=== |
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*Colonies are gray, flat, and may have a "Medusa head" or "comet" appearance |
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*The main toxin has subunits A and B |
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**A subunit may be either EF (edema factor) or LF (lethal factor) |
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**B subunit is the protective antigen, against which antibodies react |
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*Lives in soil |
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*Wild and farm animals that have contact with contaminated soil is a common exposure, including to wool and animal hides |
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*Can also be acquired by inhalation of spores |
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==Clinical Manifestations== |
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===Cutaneous Anthrax=== |
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*Caused by inoculation of spores into soft tissue |
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*Incubation period of [[Usual incubation period::2 to 5 days]] |
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*Lesion develops at site of inoculation, starting as erythemaous papule, then ulceration, then eschar |
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*May progress to sepsis |
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===Pulmonary Anthrax=== |
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*Caused by inhalation of spores |
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*Also known as woolsorter's disease |
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*Start with malaise, fever, and nonproductive cough, followed by respiratory distress, severe pulmonary edema, and death |
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===Gastrointestinal Anthrax=== |
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*Caused by ingestion of spores |
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*Infects oropharynx or abdomen |
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== Management == |
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* Inhalational anthrax: [[ciprofloxacin]] 400 mg IV q12h ± a second antibiotics |
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* Cutaneous anthrax (mild): [[ciprofloxacin]] 500 mg p.o. q12h, [[doxycycline]] 100 mg p.o. q12h, or [[amoxicillin]] 500-1000 mg p.o. q8h |
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** Duration typically 7 to 10 days (naturally acquired) or 60 days (bioterrorism-related) |
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* Meningitis: [[ciprofloxacin]] plus [[meropenem]] plus [[linezolid]] |
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** Duration 2-3 weeks, then prophylaxis to complete 60 days |
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* Almost universally susceptible to [[ciprofloxacin]] and [[doxycycline]][[CiteRef::maxson2022sy]] |
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* Generally susceptible to [[penicillin]], though should wait for susceptibility results before using |
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* Often resistant to extended-spectrum β-lactams such as [[ceftriaxone]] and [[ceftazidime]], as well as [[aztreonam]] and [[TMP-SMX]] |
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[[Category:Gram-positive bacilli]] |
[[Category:Gram-positive bacilli]] |
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Latest revision as of 17:17, 19 September 2024
Background
Microbiology
- Gram-positive bacillus that is distinguished from other Bacillus by being non-motile and non-hemolytic
- Colonies are gray, flat, and may have a "Medusa head" or "comet" appearance
- The main toxin has subunits A and B
- A subunit may be either EF (edema factor) or LF (lethal factor)
- B subunit is the protective antigen, against which antibodies react
- Lives in soil
- Wild and farm animals that have contact with contaminated soil is a common exposure, including to wool and animal hides
- Can also be acquired by inhalation of spores
Clinical Manifestations
Cutaneous Anthrax
- Caused by inoculation of spores into soft tissue
- Incubation period of 2 to 5 days
- Lesion develops at site of inoculation, starting as erythemaous papule, then ulceration, then eschar
- May progress to sepsis
Pulmonary Anthrax
- Caused by inhalation of spores
- Also known as woolsorter's disease
- Start with malaise, fever, and nonproductive cough, followed by respiratory distress, severe pulmonary edema, and death
Gastrointestinal Anthrax
- Caused by ingestion of spores
- Infects oropharynx or abdomen
- Causes sepsis
Management
- Inhalational anthrax: ciprofloxacin 400 mg IV q12h ± a second antibiotics
- Cutaneous anthrax (mild): ciprofloxacin 500 mg p.o. q12h, doxycycline 100 mg p.o. q12h, or amoxicillin 500-1000 mg p.o. q8h
- Duration typically 7 to 10 days (naturally acquired) or 60 days (bioterrorism-related)
- Meningitis: ciprofloxacin plus meropenem plus linezolid
- Duration 2-3 weeks, then prophylaxis to complete 60 days
- Almost universally susceptible to ciprofloxacin and doxycycline1
- Generally susceptible to penicillin, though should wait for susceptibility results before using
- Often resistant to extended-spectrum β-lactams such as ceftriaxone and ceftazidime, as well as aztreonam and TMP-SMX
References
- ^ Tucker Maxson, Thiphasone Kongphet-Tran, Thitipong Mongkolrattanothai, Tatiana Travis, Katherine Hendricks, Corinne Parker, Heather P McLaughlin, Julia Bugrysheva, Frank Ambrosio, Pierre Michel, Blake Cherney, Christine Lascols, David Sue. Systematic Review of In Vitro Antimicrobial Susceptibility Testing for Bacillus anthracis, 1947–2019. Clinical Infectious Diseases. 2022;75(Supplement_3):S373-S378. doi:10.1093/cid/ciac520.
