Brucella melitensis: Difference between revisions

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Brucella melitensis
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==Background==
* Causes brucellosis, also called Malta fever
 
   
 
*Causes '''brucellosis''', also called '''Malta fever'''
== Background ==
 
=== Microbiology ===
 
* Facultative intracellular, [[Stain::Gram-negative]] [[Cellular shape::coccobacillus]]
 
* [[Catalase test::Catalase-positive]], [[Oxidase test::oxidase-positive]], [[Nitrate test::nitrate-positive]], and [[Urease test::urease-positive]]
 
   
=== Epidemiology ===
+
===Microbiology===
* Zoonotic transmission transmitted by ingesting contaminated food (such as unpasteurized milk products), direct contact with an infected animal, or inhalation of aerosols
 
   
 
*Facultative intracellular, [[Stain::Gram-negative]] [[Shape::coccobacillus]]
== Clinical Manifestations ==
 
 
*Catalase [[Catalase::positive]], oxidase [[Oxidase::positive]], nitrate [[Nitrate::positive]], and urease [[Urease::positive]]
* Exposure to unpasteurized milk products or animals
 
  +
*Non-motile
* Undulating fever
 
  +
*[[Biosafety risk groups|Risk group 3 organism]]
* Headache, arthralgia, night sweats, fatigue, anorexia
 
  +
*When suspected, plates should be sealed and it should ''not'' be set up for mass spectrometry
* Arthritis, spondylitis, osteomyelitis
 
* Orchitis and epididymitis
 
* Foul-smelling sweat
 
   
== Management ==
+
===Epidemiology===
* [[Is treated by::Gentamicin]], [[Is treated by::streptomycin]], [[Is treated by::doxycycline]], [[Is treated by::TMP-SMX]]
 
   
 
*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
  +
*Incubation period is usually [[Usual incubation period::2-4 weeks]] (range [[Incubation period range::5 days to 6 months]])
 
*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==
  +
  +
*Uncomplicated infection
  +
**First-line: [[Is treated by::doxycycline]] 100 mg PO bid for 6+ weeks, plus [[Is treated by::streptomycin]] 1 g IM daily for 2 to 3 weeks
  +
**Alternative: [[doxycycline]] 100 mg Pp bid for 6+ weeks, plus [[gentamicin]] 5 mg/kg IM daily for 1 week
  +
**Alternative: [[doxycycline]] 100 mg PO bid plus [[rifampin]] 600 to 900 mg (15 mg/kg) PO daily for 6+ weeks
  +
*Neurobrucellosis:
  +
**First-line: [[ceftriaxone]] 2 g IV q12h for 1+ month, plus [[doxycycline]] 100 gm PO bid and [[rifampin]] 600 to 900 mg (15 mg/kg) PO daily for 4-5 months
  +
**Alternative: [[TMP-SMX]] 160/800 mg PO bid, plus [[doxycycline]] 100 mg PO bid, plus [[rifampin]] 600 to 900 mg (15 mg/kg) PO daily for 5 to 6 months
  +
*Pregnancy
  +
**[[Rifampin]] 900 mg PO daily for 6+ weeks, ± [[TMP-SMX]] between the 13th and 36th weeks of gestational
  +
  +
==Prevention==
  +
  +
===Lab Safety===
  +
  +
*Assess risk and provide prophylaxis and monitoring per [https://www.cdc.gov/brucellosis/laboratories/risk-level.html CDC guidelines]
  +
*Assess risk
  +
**Minimal risk
  +
***Manipulating routine specimen or enriched material in BSL2 with PPE
  +
***Being present while someone manipulates a routine specimen in BSL2, or on an open bench without aerosol-generating procedures
  +
***Manipulating or being present while someone manipulates enriched material in BSL2
  +
**Low risk
  +
***Being present more than 5 feet from someone manipulating enriched material on an open bench, without aerosol-generating procedures
  +
**High risk
  +
***Manipulating a routine specimen resulting in contact with broken skin or mucous membranes
  +
***Being present less than 5 feet from someone manipulating enriched material outside of a BSL2
  +
***Manipulating enriched material within a BSL2 without PPE
  +
***Being present in the lab during an aerosol-generating procedure
  +
*Aerosol-generating procedures include centrifuging without sealed carriers, vortexing, sonicating, spillage/splashes
  +
*Enriched material includes positive blood cultures, and reproductive clinical specimens (amniotic fluid, placental products) should be treated similarly
  +
*People with high-risk exposures should have post-exposure prophylaxis and follow-up
  +
**PEP with [[doxycycline]] 100 mg PO bid plus [[rifampin]] 600 mg PO daily for 21 days
  +
***Either can be replaced by [[TMP-SMX]] if contraindications exist, but should ensure two effect antibiotics are used
  +
**Follow-up
  +
***Daily fever checks and weekly symptom watch for 24 weeks after last known exposure
  +
***Serial serology at 0, 6, 12, 18, and 24 weeks after last known exposure
 
{{DISPLAYTITLE:''Brucella melitensis''}}
 
{{DISPLAYTITLE:''Brucella melitensis''}}
 
[[Category:Gram-negative coccobacilli]]
 
[[Category:Gram-negative coccobacilli]]

Latest revision as of 12:27, 17 August 2022

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
  • Incubation period is usually 2-4 weeks (range 5 days to 6 months)
  • 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

Management

  • Uncomplicated infection
  • Neurobrucellosis:
    • First-line: ceftriaxone 2 g IV q12h for 1+ month, plus doxycycline 100 gm PO bid and rifampin 600 to 900 mg (15 mg/kg) PO daily for 4-5 months
    • Alternative: TMP-SMX 160/800 mg PO bid, plus doxycycline 100 mg PO bid, plus rifampin 600 to 900 mg (15 mg/kg) PO daily for 5 to 6 months
  • Pregnancy
    • Rifampin 900 mg PO daily for 6+ weeks, ± TMP-SMX between the 13th and 36th weeks of gestational

Prevention

Lab Safety

  • Assess risk and provide prophylaxis and monitoring per CDC guidelines
  • Assess risk
    • Minimal risk
      • Manipulating routine specimen or enriched material in BSL2 with PPE
      • Being present while someone manipulates a routine specimen in BSL2, or on an open bench without aerosol-generating procedures
      • Manipulating or being present while someone manipulates enriched material in BSL2
    • Low risk
      • Being present more than 5 feet from someone manipulating enriched material on an open bench, without aerosol-generating procedures
    • High risk
      • Manipulating a routine specimen resulting in contact with broken skin or mucous membranes
      • Being present less than 5 feet from someone manipulating enriched material outside of a BSL2
      • Manipulating enriched material within a BSL2 without PPE
      • Being present in the lab during an aerosol-generating procedure
  • Aerosol-generating procedures include centrifuging without sealed carriers, vortexing, sonicating, spillage/splashes
  • Enriched material includes positive blood cultures, and reproductive clinical specimens (amniotic fluid, placental products) should be treated similarly
  • People with high-risk exposures should have post-exposure prophylaxis and follow-up
    • PEP with doxycycline 100 mg PO bid plus rifampin 600 mg PO daily for 21 days
      • Either can be replaced by TMP-SMX if contraindications exist, but should ensure two effect antibiotics are used
    • Follow-up
      • Daily fever checks and weekly symptom watch for 24 weeks after last known exposure
      • Serial serology at 0, 6, 12, 18, and 24 weeks after last known exposure