Comparison of Three Blood Culture Techniques in the Diagnosis of Human Brucellosis

Abstract

Background:Isolation of Brucella is the gold standard in the laboratory diagnosis of brucellosis. As Brucella is intracellular and the number of circulating bacteria is usually low, removal/dilution of antibacterial substances, concentration of bacteria and optimal culture conditions may enhance the rate of isolation.Aims and Objectives:The objective of the following study was to compare the lysis concentration (LC), clot culture and conventional Castaneda blood culture techniques for the isolation rate and recovery time in the diagnosis of human brucellosis.Materials and Methods:Blood cultures by LC, clot culture and conventional method were performed in 169 patients who had antibody titers ≥160 international units by the serum agglutination test.Results:Overall blood culture positivity was found to be 24.8%, 43.1% and 34.9% by conventional, LC and clot culture techniques in that order. The mean recovery time by LC and clot culture techniques was significantly less than conventional method, resulting in an overall difference of nearly 6 and 4 days respectively.Conclusions:For the isolation of Brucella from blood, LC and clot culture techniques are better than the conventional technique.

Optical and dielectric sensors based on antimicrobial peptides for microorganism diagnosis

“…However, these methods are time-consuming and require specialized technicians. Of note, it may require weeks to obtain a correct diagnosis of some pathogens from samples of mucosa, skin, or blood (Benes et al, 1996). Unfortunately, a few days may be sufficient to significantly worsen the clinical status of the patient before receiving appropriate treatment.…”

Comparative evaluation of the Brucella Coombs gel test in laboratory diagnosis of human brucellosis

“…[3,11,12] The most commonly used serological tests are the Rose Bengal (RB) plate test and the standard serum tube agglutination (STA) test. [3,11] However, these commonly used tests cannot detect so-called 'incomplete/ blocking antibodies' that prevent agglutination, especially in chronic patients.…”

Blood Cultures for the Diagnosis of Human Brucellosis

“…Of the 27 patients with chronic disease, the detection rates were 3.3% (n=9) for the Castañeda flask and 74.1% (n=20) for the lysis centrifugation method (P=0.087), and the timeto-detection was 7.2±2.6 and 2.7±1.4 days, respectively (P=0.001). In a more recent study, the lysis centrifugation recovered B. melitensis in 73 (43.1%) of 169 serologically-confirmed human cases, compared to 42 (24.8%) detected by the blood clot culture and 59 (34.9%) by the Castañeda technique, and the detection time was significantly shorter [29].…”

“…In a comparative study of 169 serologically confirmed patients, Mangalgi and Sajjan reported a detection rate of 34.9% for the clot culture, 24.8% for the Castañeda flask, and 43.1% for the lysis concentration method; the mean±SD recovery times were 5.8±1.4, 9.6±1.7, and 4.1±0.9 days, respectively [29]. In a second study by the same research group, blood clot cultures were clearly superior to conventional broth cultures of whole blood for isolating brucellae, increasing the yield by >20% and shortening the time-to-positivity from an average of 8.2 days to 3.1 days [59].…”

“…The method consists of collecting a blood sample in a sterile tube and allowing it to cloth. The tube is then centrifuged and the serum is separated aseptically and used for serological assays, whereas the clot is disrupted by shaking the tube and seeded into appropriate media [29]. Available data on the advantages of this technique, however, are limited and contentious.…”