Brucella

Marston in 1861; the English military surgeon David Bruce isolated the pathogens named after him in the spleen of a deceased patient in 1887.

Brucelli are small, gram-negative, unflagellated, coccoid, pleomorphic rod-shaped bacteria. Of humapathogenic importance are 4 species that cause clinically very similar clinical pictures.

The following species are of human pathological importance:

• Brucella abortus (causative agent of M. Bang = Febris undulans bovina): main host is cattle (causes a general febrile infection there).
• Brucella melitensis (causative agent of Malta fever = Mediterranean fever, Febris mediterranea, Febris undulans melitensis, Bruce septicaemia, wave fever): Main hosts are sheep and goats.
• Brucella suis (porcine brucellosis = brucellosis suis): the main host is the pig.
• Brucella canis (canine brucellosis): the main host is dogs.

B. abortus: Found worldwide, especially in temperate and tropical areas where cattle are raised. They can survive for weeks in unpasteurized milk. Also in the products made from it.

Brucella melitensis: Mediterranean region, Africa, South America.

Brucella suis: North America.

Infection with Bruzella spp., especially when transmitted through raw milk, direct contact with infected animals (sheep, goats, cattle, pigs) or their tissues, and inhalation of infected aerosols. The pathogens frequently enter the body on previously damaged skin or conjunctivae (smear infection). Transmission from person to person only in exceptional cases.

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Brucellosis is a classical anthropozoonosis. Primarily animals are affected from which the pathogens are transmitted to humans. Human infections occur through contact with the diseased animals. Depending on the site of entry, a localised inflammation with uncharacteristic symptoms and disturbance of the general condition may occur.

The pathogens are taken up by granulocytes. In these they can survive unharmed because they inhibit phagosomes/lysosomes/fusion. They are carried to the regional lymph nodes(lymphadenitis) and from there spread to all organs.

Brucella can multiply specifically in cells of the RES (spleen, liver, bone marrow) and reproductive organs of both sexes. There, non-caseating granulomas develop.

Medical history (farmers, butchers, veterinarians, drinking raw milk; travel to Mediterranean countries).

Laboratory: Microscopic and cultural detection of pathogens from blood and body fluids, organ punctates, lymph node biopsy.

Antibody detection (IgG, IgM, titer rise) with ELISA, CFT or agglutination reaction according to Widal.

Listeriosis; tuberculosis; syphilis; measles; scarlet fever; erythema exsudativum multiforme; pityriasis rosea.

Therapy of choice: Doxycycline 200mg/day p.o. + Rifampicin 600-900mg/day p.o. for 6 weeks.

Alternative: combination of tetracycline (e.g. Tetracycline Wolff) 2 g/day for 3-6 weeks and streptomycin (e.g. Strepto-Fatol) 1 g/day i.v. or i.m. for 2 weeks. For mild infections, monotherapy with tetracyclines is sufficient.

Alternative: Doxycycline 2 times/day 100 mg p.o. instead of tetracycline.

In children under 12 years: Trimethoprim/Sulfamethoxazol(e.g. Cotrimox-Wolff Saft 1/2-2 Messl. depending on age) for 4 weeks. Combination of this therapy with rifampicin (e.g. Eremfat) 10-15 mg/kg bw/day p.o. is recommended. Treatment with rifampicin alone is not advisable due to rapid development of resistance.

With therapy in the acute phase (therapy start during the first 3 months) the chances of cure are 90-100%, later 60-80%.

If therapy is started late, it is often not possible to completely eliminate the pathogens; chronic courses lasting years with recurrent flare-ups of the disease are possible. In approx. 5% of treated cases, relapses occur due to persistent sensitive pathogens, so that a new therapy attempt can be made with the existing regime if necessary (antibiogram!).

The detection of Brucella is notifiable according to the Infection Protection Act (IFSG). Isolation not necessary, as no human-to-human infection occurs.

1. Ariza J et al. (1992) Treatment of human brucellosis with doxycycline plus rifampicin or doxycycline plus streptomycin. A randomized, double-blind study. Ann Intern Med 117: 25-30
2. Bang B (1897) The aetiology of epidemic ("infectious") shedding. Z Tiermedicin 1: 241-278
3. Bruce D (1887) Note on the discovery of a microorganism in Malta fever. Practitioner (London) 39: 161-170
4. Marston JA (1861) Report on fever (Malta). Royal Army Med Dept Rep 3: 486-521
5. Mazokopakis E et al (2003) Acute brucellosis presenting with erythema nodosum. Eur J Epidemiol 18: 913-915
6. McLean DR et al (1992) Neurobrucellosis: clinical and therapeutic features. Clin Infect Dis 15: 582-590
7. Metin A et al (2001) Cutaneous findings encountered in brucellosis and review of the literature. Int J Dermatol 40: 434-438
8. Milionis H et al (2000) Cutaneous manifestations in brucellosis: case report and review of the literature. Infection 28: 124-126
9. Weil Y et al (2003) Brucella prosthetic joint infection: a report of 3 cases and a review of the literature. Clin Infect Dis 36: e81-86