Isolation of Brucella melitensis and Brucella abortus from brucellosis patients and animals by culture method and molecular method (PCR)

Objective: Isolation of Brucella melitensis and Brucella abortus, from patients suspect to have brucellosis and animals by conventional culture and comparison with PCR technique in diagnosis of human and animal brucellosis. Duration and place of study: Samples were obtained from suspected brucellosis patients, referred to many hospitals in Baghdad city, which include: Al-Yarmook, Al-Karama, Al-Shaheed Al-Sadder, Al-Imam Ali (peace be upon him) and Al-Kadhmiya Hospitals, while samples were obtained from animals, referred to Al-Fudhailiyah and Al-Husainia regions in Baghdad, during the duration from (November 2009 to November 2010). Methodology: A total 178 peripheral blood samples were collected from patients with high suspect brucellosis and 15 peripheral blood samples were from animals. The samples were inoculated into Brucella agar or trypticase soy agar and blood agar and after 7-30 days, the isolated colonies were identified by inoculation into Brucella agar or trypticase soy agar and identified by biochemical tests. DNA extraction was carried out using a commercial kit and a laboratory extraction procedure and examined by PCR involving specific primers for B.melitensis and B.abortus based on IS711 in the Brucella chromosome. Results: We identified 3 isolates of Brucella form animals using culture and biochemical methods but no isolation from patients. When PCR technique was applied to patients and animals blood, 3 patient blood samples were positive for B.melitensis and 10 patient blood samples were positive for B.abortus but 3 animal blood samples were positive for B.melitensis and 6 animal blood samples were positive for B.abortus. Conclusions: The results of present study showed that PCR assay is a rapid and sensitive technique for diagnosis of brucellosis compared to culture method. However it is more valuable when coupled with conventional methods.