Predictors of Blood Culture Positivity in Pediatric Brucellosis

To investigate the predictors of blood culture positivity in children with brucellosis.

Descriptive study.

Department of Pediatric Infectious Diseases in Erzurum Regional Training and Research Hospital, Turkey, from January to December 2015.

Eighty-six children under 16 years of age, with brucellosis, were retrospectively evaluated. Compatible clinical findings plus presence of positivity at titers of >1:160 in serum and/or Coombs agglutination tests in a single serum sample and/or a minimum fourfold increase within a 2-3 week interval were diagnostic for brucellosis. Only patients with blood cultures were included. Patients' demographical, clinical, and laboratory risk factors, such as age, gender, presence and duration of symptoms, and laboratory characteristics were analysed.

Brucella spp. grew in blood cultures of 24 (27.9%) patients. Children with blood culture positivity had shorter symptom duration than those with negative blood cultures (p=0.03). Absence of personal and household histories of brucellosis (p=0.02 and p=0.04, respectively), lower hemoglobin, iron, and vitamin D (p<0.001, p=0.006, and p=0.006, respectively), and higher leukocyte, CRP, and ferritin (p<0.001, p=0.001, and p<0.001, respectively) levels were associated with isolation of Brucella spp. in blood culture. Children with positive blood cultures had higher serum tube and Coombs agglutination test results (p=0.001 and p<0.001). ROC analysis showed that ferritin at a cut-off level of 122 ng/mL (CI 95% 0.86-0.97, p<0.001) and Brucella Coombs agglutination test at a cut-off level of 1/480 (CI 95% 0.84-0.96, p<0.001) were the most sensitive and specific predictors of bacteremia.

Serum hemoglobin, iron, ferritin, vitamin D, and C-reactive protein levels, Brucellar tube and Coombs agglutination tests, and leukocyte count could help to predict definitive diagnosis in pediatric brucellosis when molecular techniques are not feasible, such as in source-limited countries.