Brucellosis: an update - The perspective from the Mediterranean basin

Brucellosis is still a relevant public health hazard in many different part s of the world. The capacity of Brucella to survive in macrophages determin es the undulant course of the disease and its tendency to relapse and progr ess to a chronic condition. The structure of the Brucella outer membrane di ffers from that of classical Gram-negative bacteria, which may be responsib le for its peculiar intracellular parasitism. Cell-mediated immunity is the principal defence mechanism. Brucella melitensis is the most frequently re ported species, and produces the most severe human disease. In countries wh ere the disease is endemic, it is usually caused by B. melitensis and is of ten associated with consumption of dairy products or with direct contact wi th animals or animal products. Human brucellosis due to Brucella abortus an d Brucella suis is usually occupational disease. Brucellosis is a systemic infection that often develops focal disease involving any organ or tissue o f the body. A recently developed automated culture system is able to isolat e the micro-organism in only 3-5 days, and serological diagnosis may be mad e using agglutination and Coombs' tests, or enzyme-linked immunosorbent ass ay (ELISA). Due to the lack of antigen standardisation and the confused int erpretation of results, objections to the routine use of ELISA have been ra ised. Persistent agglutinating and nonagglutinating immunoglobulin (Ig)-G t itres are often found in patients with satisfactory clinical outcome, but n evertheless, a clear increase in IgG titres over time may suggest relapse o r persisting infection. A combination of doxycycline and aminoglycoside the rapy for 6 and 2 weeks respectively is currently considered the treatment o f choice for human brucellosis. Follow-up of patients after therapy require s judicious clinical management because no adequate criteria for defining ' cure' have been established. (C) 1999 Lippincott Williams & Wilkins.