Brucella species


Gram-Negative Cocci & Coccobacilli   
>Aggregatibacter aphrophilus (formally known as Haemophilus aphrophilus)
>Bordetella pertussis (Causative agent of pertussis or whooping cough. )
>Brucella species: Led
     1] Brucella abortus (cattle)
     2] Brucella canis (dogs)
     3] Brucella melitensis (goat)
     4] Brucella suis
>Eikenella corrodens
>Haemophilus species:
     1] Haemophilus influenzae
     2] Haemophilus ducreyi
     3] Haemophilus avium
>Moraxella catarrhalis (formerly known as Branhamella catarrhalis)
>Neisseria species:  (frequently colonize mucosal surfaces.)
     1] Neisseria gonorrhoeae
     2] Neisseria meningitidis
>Pasteurella multocida

Brucella species:  

  • non-motile, non-encapsulated coccobacilli, which function as facultative intracellular parasites. 
  • Cause of brucellosis, which  is transmitted by ingesting contaminated food (such as unpasteurized milk products), direct contact with an infected animal, or inhalation of aerosols.
  • Source:

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Important considerations:  The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions.   Generally, the most common agents/regimens are listed first.  Listed dosages may need to be adjusted for renal dysfunction. 

Adults and children >8 years old:

  1. PrimaryDoxycycline 100mg orally or IV twice daily x 6 weeks PLUS  [ Streptomycin 15 mg/kg (or 1 gram) IM once daily x 14 days  OR  Gentamicin 5 mg/kg/day IV  (Adjust frequency based on estimated clearance) x 7 days]
  2. Secondary:
    • Doxycycline 100mg orally or IV twice daily  PLUS  Rifampin 600-900mg orally once daily x 6 weeks.  OR
    • Ciprofloxacin 500 mg orally twice daily  PLUS  [ Doxycycline 100mg orally or IV twice daily  OR Rifampin 600-900mg orally once daily] x 6 weeks
  3. Review specialized reference(s) for neurological involvement and treatment of pregnant patients or children
         Other: TMP-SMX (Bactrim) IV/PO  PLUS  [ Gentamicin IV OR Rifampin oral].

Streptomycin comments: Streptomycin is usually administered daily as a single intramuscular injection.   For concomitant use with other agents to which the infecting organism is also sensitive: Streptomycin is considered a secondline agent for the treatment of gram-negative bacillary bactermia, meningitis, and pneumonia; brucellosis; granuloma inguinale; chancroid, and urinary tract infection.    
For adults
: 1 to 2 grams in divided doses every six to twelve hours for moderate to severe infections. Doses should generally not exceed 2 grams per day.
For children
: 20 to 40 mg/kg/day (8 to 20 mg/lb/day) in divided doses every 6 to 12 hours. (Particular care should be taken to avoid excessive dosage in children).

Brucella species