Seroepidemiological and microbiological study of brucellosis in Kuwait.

OBJECTIVE The primary objective of the study was to determine the prevalence of brucellosis and the antimicrobial susceptibility pattern of local Brucellae isolates in the Infectious Diseases Hospital, Kuwait. SUBJECTS AND METHODS A single serum sample was collected from each of 1,836 patients of different nationalities from January 2000 to December 2001. Any patient with a provisional diagnosis of fever or brucellosis had a standard tube agglutination (STA) test for the quantitation of Brucella antibodies. Blood cultures were done in 166 of 455 patients with significant STA titers, using the Bactec system. Antimicrobial susceptibility testing of 123 isolates of Brucella spp. was done against 8 antimicrobial agents. RESULTS A total of 455 serum samples (24.8%) having an STA titer of > or =1:160 were presumptively diagnosed as cases of brucellosis. The peak isolation was in April and May. Brucella spp. were isolated from 123 blood cultures (74.1%). The blood culture isolation rate was significantly higher in patients with an STA titer of >/=1:1,280 than in those with an STA titer of </=1:160 (p < 0.05). Antimicrobial susceptibility testing showed good in vitro activity of tetracycline, gentamicin, amikacin, streptomycin and ciprofloxacin against all isolates. Azithromycin had good anti-Brucella activity against only 42% of the isolates, while rifampicin and trimethoprim-sulfamethoxazole showed low in vitro anti-Brucella activity against 8 and 25% of the isolates, respectively. CONCLUSION Brucellosis is quite common in Kuwait. Kuwaiti and Bangladeshi nationals were most affected. Significant titers on the STA test were detected in 24.8% of serum samples. Good in vitro activity against all isolates was found with tetracycline, gentamicin, amikacin, ciprofloxacin and streptomycin, and low activity with azithromycin, rifampicin and trimethoprim-sulfamethoxazole.