O tratamento da brucelose é problemático devido à alta freqüência de tratamentos mal sucedidos e recidivas. Por tratar-se de um patógeno intracelular, o tratamento requer procedimentos combinados. Entretanto, existem poucos dados sobre combinações in vitro para Brucellae. O objetivo deste trabalho foi investigar a eficiência de vários tratamentos tradicionais e novas combinações de antibióticos contra 16 isolados de Brucella melitensis. O efeito combinado foi avaliado através do método do E-test para obtenção do FIC (índice de concentração inibitória fracional). Co-trimoxazol (SXT) e moxifloxocina (MXF) apresentaram o MIC mais baixo, enquanto rifampicina (RIF) apresentou o MIC mais alto. Combinações com RIF mostraram a melhor atividade sinergística (100% para RIF-tetraciclina e 87,5% para RIF-SXT). Atividade sinergística foi também detectada para sete (43,7%) combinações de ciprofloxacina (CIP-STX), quatro (25%) de TET-MXF e duas (12,5%) de TET-SXT. As combinações que apresentaram efeito aditivo foram TET-SXT, CIP-SXT e TET-MXF. Antagonismo foi observado somente para a combinação TET-estreptomicina (STR) em três isolados (18,8%). Mais pesquisas utilizando ensaios clínicos randomizados controlados são necessárias para avaliar a utilidade desses dados.

The treatment of brucellosis is still problematic, because of high rates of treatment failure or relapses. As the microorganism is an intracellular pathogen, treatment requires combined regimens. However, limited existing data on in vitro combinations are avaliable for Brucellae. The aim of this study was to investigate the in vitro efficacy of various traditional and new antibiotic combinations against 16 Brucella melitensis strains. The combination effect of antimicrobial agents was evaluated by E-test synergy method to obtain a fractional inhibitory concentration (FIC) index. Co-Trimoxazole (SXT) and moxifloxocin (MXF) exhibited the lowest MIC, while Rifampin (RIF) had the highest MIC in the study. Combinations with RIF showed the best synergistic activity (100% of RIF-tetracycline (TET), and 87.5% of RIF-SXT). Synergistic activity was also detected at seven (43.7%) of ciprofloxocin (CIP)-SXT, four (25%) of TET-MXF, and two (12.5%) of TET-SXT combinations. The combinations that demonstrated additivity were TET-SXT, CIP-SXT and TET-MXF. Antagonism was observed only with the TET-Streptomycin (STR) combination in three strains (18.8%). Further work including randomized controlled clinical trials is required to fully evaluate the usefulness of these data.

Brucellosis is a multisystemic disease that rarely leads to a fatal outcome. While reticuloendothelial system organs are mostly affected, peritonitis and posthepatitic cirrhosis are also complications of brucellosis, though they are very rare. Brucella spp. can also trigger immunological reactions. We report a case of brucellosis with peritonitis, renal failure and leucocytoclastic vasculitis caused by Brucella melitensis, which led to a fatal outcome. Brucellosis should be considered in the differential diagnosis of vasculitic diseases, especially in endemic areas.