Brucella melitensis: Difference between revisions

Revision as of 20:18, 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
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

Management

Gentamicin, streptomycin, doxycycline, TMP-SMX

@@ Line 1: / Line 1: @@
 ==Background==
-* Causes '''brucellosis''', also called '''Malta fever'''
+*Causes '''brucellosis''', also called '''Malta fever'''
 ===Microbiology===
@@ Line 7: / Line 7: @@
 *Facultative intracellular, [[Stain::Gram-negative]] [[Cellular shape::coccobacillus]]
 *Catalase [[Catalase::positive]], oxidase [[Oxidase::positive]], nitrate [[Nitrate::positive]], and urease [[Urease::positive]]
+*Non-motile
 *[[Biosafety risk groups|Risk group 3 organism]]
 *When suspected, plates should be sealed and it should ''not'' be set up for mass spectrometry
@@ Line 15: / Line 16: @@
 ==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, osteomyelitis
+*Arthritis, spondylitis (especially sacroiliac and other large lower-extremity joints), osteomyelitis
+*Hepatomegaly, splenomegaly, and lymphadenopathy
-*Orchitis and epididymitis
+*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
+* 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]]
 ==Management==