Chromobacterium violaceum: Difference between revisions

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Chromobacterium violaceum
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===Microbiology===
===Microbiology===


*[[Stain::Gram-negative]] oxidase-[[Oxidase::positive]] [[Shape::bacillus]]
*Gram-negative bacterium
**The violacein pigment is produced during aerobic growth at 22 ºC and can interfere with the oxidase test
*Colonies are deep purple to black due to the presence of the violacein pigment
*Colonies are deep purple to black due to the presence of the violacein pigment and may have an almond-like odor
*Found in water
*Found in water and soil, primarily tropics or subtropics


===Epidemiology===
===Epidemiology===
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*Mostly tropical or subtropical areas, especially southeast Asia
*Mostly tropical or subtropical areas, especially southeast Asia
*Also in southeast US, most commonly Florida
*Also in southeast US, most commonly Florida
*CGD is a risk factor for opportunistic infection, as is G6PD deficiency
*[[CGD]] is a risk factor for opportunistic infection, as is [[G6PD deficiency]]


==Clinical Manifestations==
==Clinical Manifestations==


*Causes wound infections following contaminated water exposure
*Causes wound infections following contaminated water exposure
*Typically starts with a [[cellulitis]]
*Always with systemic features, including fever (100%) and sepsis (82%)
*Always with systemic features, including [[Causes::fever]] (100%) and [[Causes::sepsis]] (82%)
*Often bacteremic (60%) and can involve visceral organs (51%), especially lung and liver
*Often [[Causes::bacteremia]] (60%) and can cause abscesses in visceral organs (51%), especially lung and liver
*High mortality (53%)
*High mortality (53%)


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*Includes other causes of skin and soft tissue infection after water exposure
*Includes other causes of skin and soft tissue infection after water exposure
*Common bugs: [[Staphylococcus aureus]], [[Streptococcus pyogenes]], other [[streptococci]], [[Klebsiella species]], [[Pseudomonas aeruginosa]], [[Escherichia coli]], and polymicrobial infections
*Common bugs: [[Staphylococcus aureus]], [[Streptococcus pyogenes]], other [[streptococci]], [[Klebsiella]], [[Pseudomonas aeruginosa]], [[Escherichia coli]], and polymicrobial infections
*Uniquely marine bacteria: [[Aeromonas species]], [[Vibrio vulnificus]], [[Shewanella species]], [[Edwardsiella species]], [[Chromobacterium species]]
*Uniquely marine bacteria: [[Aeromonas]], [[Vibrio vulnificus]], [[Shewanella]], [[Edwardsiella]], [[Chromobacterium]]
*Others: [[Burkholderia pseudomallei]], [[non-tuberculous mycobacteria]], and some [[fungi]]
*Others: [[Burkholderia pseudomallei]], [[non-tuberculous mycobacteria]], and some [[fungi]]


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*[[Fluoroquinolones]], [[chloramphenicol]], [[tetracyline]], [[TMP-SMX]], [[imipenem]], [[gentamicin]]
*[[Fluoroquinolones]], [[chloramphenicol]], [[tetracyline]], [[TMP-SMX]], [[imipenem]], [[gentamicin]]
*Maybe [[cefotaxime]], [[ceftazidime]], [[imipenem]]
*Avoid first- and second-generation cephalosporins


==Further Reading==
==Further Reading==

Latest revision as of 01:51, 2 August 2025

Background

Microbiology

  • Gram-negative oxidase-positive bacillus
    • The violacein pigment is produced during aerobic growth at 22 ºC and can interfere with the oxidase test
  • Colonies are deep purple to black due to the presence of the violacein pigment and may have an almond-like odor
  • Found in water and soil, primarily tropics or subtropics

Epidemiology

  • Mostly tropical or subtropical areas, especially southeast Asia
  • Also in southeast US, most commonly Florida
  • CGD is a risk factor for opportunistic infection, as is G6PD deficiency

Clinical Manifestations

  • Causes wound infections following contaminated water exposure
  • Typically starts with a cellulitis
  • Always with systemic features, including fever (100%) and sepsis (82%)
  • Often bacteremia (60%) and can cause abscesses in visceral organs (51%), especially lung and liver
  • High mortality (53%)

Differential Diagnosis

Management

Further Reading