Evaluation of PCR, Culture and Serology for the Diagnosis of Acute Human Brucellosis

Abstract

Background:The diagnosis of brucellosis is frequently difficult to establish. This is not only because clinically, the disease can mimic any infectious and noninfectious disease, but also because the established diagnostic methods are not always successful. In this study, we have tried to evaluate PCR techniques in the diagnosis of brucellosis in comparison to conventional techniques. Patients and Methods: Fifty peripheral blood samples from the following groups were collected: patients with brucellosis (17); patients with febrile illnesses due to factors other than brucella etiology (19); symptomatic occupationally exposed persons (9); and healthy volunteers (5). The last three groups were considered controls. Among the 17 Brucella samples, only 14 were obtained before treatment was begun. The samples were tested by serology, using the standard tube agglutination method (STA), blood culture using Bactec machines, and PCR using primer pair to amplify a 223-bp region within a gene coding for a 31-kD Brucella antigen. Diagnosis of brucellosis was based on compatible clinical picture in addition to positive blood culture and/or positive serology. Results: Of the 17 blood samples from patients with brucellosis, eight were culture positive for Brucella species, and all showed high titer antibrucella antibodies. Only 14 of them were positive by PCR, and these were the samples submitted before initiation of therapy, representing 100% sensitivity. Among the 33 controls, blood culture was negative for Brucella in all of them, while one sample showed high-titer antibrucella antibodies. The latter was from the febrile illnesses group. PCR-based assay was able to detect four bands in the controls, all of which were from the occupationally exposed asymptomatic group. Conclusion: In view of the several advantages of PCR over the conventional methods for the diagnosis of brucellosis, such as speed, safety, high sensitivity and specificity, the technique might be considered for laboratory diagnosis of brucellosis. However, for the evaluation of asymptomatic highly exposed persons, PCR might be considered complementary to the traditional methods and followed up by serology and/or culture.

Brucellosis among Hospitalized Febrile Patients in Northern Tanzania

“…Furthermore, in patients with serum agglutination test results suggestive of brucellosis, Brucella-positive blood culture prevalence is relatively low, ranging from 32% to 58%. 44,[64][65][66] The third limitation is that our study catchment population may not have captured the full agro-ecologic diversity of northern Tanzania. In particular, nomadic pastoralists, a group at particular risk for brucellosis, 16,22,37,38 may have been underrepresented among KCMC or MRH inpatients.…”

Characterization and evaluation of an arbitrary primed Polymerase Chain Reaction (PCR) product for the specific detection of Brucella species

“…Another disadvantage of serological test is that, even after the recovery period the infected individual will show positive reaction in serological testes (Ariza et al, 1992). Growing number of scientific literature suggest that, development of PCR based detection methods would greatly improve the efficiency of detection (Gemechu et al, 2011;Maas et al, 2007;Al-Attas et al, 2000;Keid et al, 2007;Mitka et al, 2007;Bricker 2002;Navarro et al, 1999;Asif et al, 2009).…”

Brucellosis in Immunocompromised Hosts

“…Combined with serological assays, PCR can be applied for the diagnosis of new cases of brucellosis, asymptomatic but highly exposed individuals in addition to relapsed cases regardless duration or type of the disease without relying entirely on blood cultures, particularly in chronic cases [92,239]. Combined PCR-ELISA technique is an immune-detection method that can directly quantify PCR product as it detects the nucleic acid rather than the protein [240].…”