MOLECULAR DETECTION OF BRUCELLA INFECTION IN EGYPTIAN PATIENTS

Abstract

Background: Brucellosis is a zoonotic disease, endemic in many parts of the world especially
the Middle East. It is an important health problem in Egypt. Since the clinical symptoms of human
brucellosis are protean and nonspecific, laboratory confirmation by isolation of organism or detection
of specific antibodies is necessary for the diagnosis. The objective of this study is to validate a PCR
technique for the detection of brucella infection. So, we can differentiate between the true and current
infections by this organism from the falsely positive antibodies produced from previous or treated
infections.
Methods: This study comprised 97 patients (74 males and 23 females) from different ages
experienced the clinical symptoms of brucellosis. This study was carried out at Mansoura University
Hospitals. The blood samples collected were subjected to culture, Brucella test and PCR targeting the
gene encoding a 31-kDa Brucella abortus (BCSP31).
Results: PCR standardized for the gene encoding a 31-kDa Brucella abortus “BCSP31” gene
result in specific amplicon of 223-bp. In positive PCR cases of brucella (total 14), a single band of
223bp corresponding to BCSP31 gene was obtained. The PCR assay was found to be highly specific
and the true positive brucellosis cases (n = 6) are positive of brucella test, blood culture and /or PCR.
PCR was sensitive than blood culture for diagnosis of brucellosis since the sensitivity and specificity of
PCR are 87.5% and 98.73% respectively and the sensitivity and specificity of blood culture are 84.62%
and 96.15% respectively. There was a significant correlation between brucella titre and blood culture (p
= 0.001) in patients with brucella. Furthermore, there was a significant correlation between brucella
titre and PCR (p = 0.001) in patients with brucella.
Conclusion: We recommend using PCR as an alternative to blood culture for diagnosis of
acute brucellosis. Further studies are required to compare different techniques. We also recommend
performance of a large scale study to test this PCR technique for screening for brucellosis in Egypt.