[Comparison of the diagnostic value of blood and bone marrow cultures in brucellosis].

The aim of this study was to compare the rates of brucellosis revealed by blood and bone marrow (BM) cultures obtained from patients followed up in our hospital, between 2002-2004 period. A total of 102 patients (62 male, 40 female; mean age: 39 +/- 5 years) were included to the study and 61 of them were in acute, 29 were in subacute, and 12 were in chronic stages of brucellosis. Blood and BM samples collected from all of the hospitalized patients were cultured by using the BACTEC 9050 system. The mean isolation period for BM cultures was 4.2 days, whereas it was 5.8 days for blood cultures. Overall the rate of positive blood cultures in brucellosis cases was found as 48% (n: 49), while the rate was was 34% (n: 35) for BM cultures, and the difference was statistically significant (p<0.05). Blood and BM culture positive results were detected in 40 (66%) and 28 (46%) of acute brucellosis cases, respectively. BM culture positive 23 samples yielded positive blood culture, while five were negative. These rates were found as 31% (n: 9), and 21% (n: 6) for subacute acute brucellosis cases, respectively. On the other hand Brucella spp. could not be isolated from blood cultures of 12 chronic cases, however, one (8%) was positive for BM culture. The patients were grouped according to their standard tube agglutination (STA) test results (group 1: 1/160-1/640, group 2: 1/1280-1/2560 STA titers), and when comparing these groups for their positive blood and BM culture results, the high rate in group 2 was found statistically significant (p<0.05). Nineteen (70%) of 27 patients who had previously received specific brucellosis therapy were positive for blood and/or BM cultures, indicating insufficient use of antibiotics, or the use of inappropriate antibiotic combinations. It was concluded that, since the rate of positive blood cultures were low in especially chronic brucellosis cases, bone marrow cultures should be obtained for the definite evaluation of these patients.