Brucella melitensis: Difference between revisions
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Brucella melitensis
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==Background== |
==Background== |
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| − | * |
+ | *Causes '''brucellosis''', also called '''Malta fever''' |
===Microbiology=== |
===Microbiology=== |
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*Facultative intracellular, [[Stain::Gram-negative]] [[Cellular shape::coccobacillus]] |
*Facultative intracellular, [[Stain::Gram-negative]] [[Cellular shape::coccobacillus]] |
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*Catalase [[Catalase::positive]], oxidase [[Oxidase::positive]], nitrate [[Nitrate::positive]], and urease [[Urease::positive]] |
*Catalase [[Catalase::positive]], oxidase [[Oxidase::positive]], nitrate [[Nitrate::positive]], and urease [[Urease::positive]] |
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| + | *Non-motile |
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*[[Biosafety risk groups|Risk group 3 organism]] |
*[[Biosafety risk groups|Risk group 3 organism]] |
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*When suspected, plates should be sealed and it should ''not'' be set up for mass spectrometry |
*When suspected, plates should be sealed and it should ''not'' be set up for mass spectrometry |
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==Clinical Manifestations== |
==Clinical Manifestations== |
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| + | |||
| + | === Brucellosis === |
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*Exposure to unpasteurized milk products or animals |
*Exposure to unpasteurized milk products or animals |
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| + | *A common cause of fever without a focus in endemic countries |
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*Undulating fever |
*Undulating fever |
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*Headache, arthralgia, night sweats, fatigue, anorexia |
*Headache, arthralgia, night sweats, fatigue, anorexia |
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| − | *Arthritis, spondylitis, osteomyelitis |
+ | *Arthritis, spondylitis (especially sacroiliac and other large lower-extremity joints), osteomyelitis |
| + | *Hepatomegaly, splenomegaly, and lymphadenopathy |
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| − | *Orchitis and epididymitis |
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| + | *Orchitis and epididymitis, prostatitis, and tubo-ovarian abscess |
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*Foul-smelling sweat |
*Foul-smelling sweat |
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| + | *Can have mild pancytopenia |
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| + | === Relapsed Brucellosis === |
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| + | |||
| + | * Occurs within six months of completing treatment in about 10% of patients |
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| + | == Diagnosis == |
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| + | |||
| + | * Culture |
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| + | ** May be isolated from blood culture, but only intermittent and is a fastidious organism |
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| + | *** Sensitivity is 50-70% |
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| + | *** Cultures should be held for 10 days |
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| + | ** Grows slowly on blood and chocolate agar; better on ''Brucella'' agar |
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| + | ** On gram stain, the small coccobacilli look like fine grains of sand |
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| + | * Serology |
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| + | ** Acute and convalescent serology showing a fourfold rise in titres |
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| + | ** Serum agglutination test titres of 1:160 or greater in the right clinical context |
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| + | *** Cross-reacts with [[Francisella tularensis]] and [[Vibrio cholerae]] |
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==Management== |
==Management== |
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Revision as of 16:18, 10 September 2020
Background
- Causes brucellosis, also called Malta fever
Microbiology
- Facultative intracellular, Gram-negative coccobacillus
- Catalase positive, oxidase positive, nitrate positive, and urease positive
- Non-motile
- Risk group 3 organism
- When suspected, plates should be sealed and it should not be set up for mass spectrometry
Epidemiology
- Zoonotic transmission transmitted by ingesting contaminated food (such as unpasteurized milk products), direct contact with an infected animal, or inhalation of aerosols
Clinical Manifestations
Brucellosis
- Exposure to unpasteurized milk products or animals
- A common cause of fever without a focus in endemic countries
- Undulating fever
- Headache, arthralgia, night sweats, fatigue, anorexia
- Arthritis, spondylitis (especially sacroiliac and other large lower-extremity joints), osteomyelitis
- Hepatomegaly, splenomegaly, and lymphadenopathy
- Orchitis and epididymitis, prostatitis, and tubo-ovarian abscess
- Foul-smelling sweat
- Can have mild pancytopenia
Relapsed Brucellosis
- Occurs within six months of completing treatment in about 10% of patients
Diagnosis
- Culture
- May be isolated from blood culture, but only intermittent and is a fastidious organism
- Sensitivity is 50-70%
- Cultures should be held for 10 days
- Grows slowly on blood and chocolate agar; better on Brucella agar
- On gram stain, the small coccobacilli look like fine grains of sand
- May be isolated from blood culture, but only intermittent and is a fastidious organism
- Serology
- Acute and convalescent serology showing a fourfold rise in titres
- Serum agglutination test titres of 1:160 or greater in the right clinical context
- Cross-reacts with Francisella tularensis and Vibrio cholerae
