Bacillus anthracis: Difference between revisions

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.

@@ Line 1: / Line 1: @@
+==Background==
-*Causes '''anthrax'''
-== Background ==
+===Microbiology===
+*[[Stain::Gram-positive]] [[Shape::bacillus]] that is distinguished from other [[Bacillus]] by being [[Motility::non-motile]] and [[Hemolysis::non-hemolytic]]
-=== Microbiology ===
+*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==
-*[[Stain::Gram-positive]] [[Cellular shape::bacillus]] that is distinguished from other [[Bacillus species]] by being non-motile and non-hemolytic
+===Cutaneous Anthrax===
-== Clinical Manifestations ==
+*Caused by inoculation of spores into soft tissue
-=== Cutaneous anthrax ===
+*Incubation period of [[Usual incubation period::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 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
+*Caused by inhalation of spores
-=== Pulmonary anthrax ===
+*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 inhalation of spores
-* Also known as woolsorter's disease
+*Caused by ingestion of spores
-* Start with malaise, fever, and nonproductive cough, followed by respiratory distress, severe pulmonary edema, and death
+*Infects oropharynx or abdomen
+*Causes sepsis{{DISPLAYTITLE:''Bacillus anthracis''}}
+== 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 [[doxycycline]][[CiteRef::maxson2022sy]]
+* 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]]
-=== Gastrointestinal anthrax ===
-* Caused by ingestion of spores
-* Infects oropharynx or abdomen
-* Causes sepsis
-<br />{{DISPLAYTITLE:''Bacillus anthracis''}}
 [[Category:Gram-positive bacilli]]