A comparison between light cycler real-timepolymerase chain reaction (PCR)‎ assay and serological methods used in the diagnosis of human brucellosis

Abstract EN

This study was conducted to compare the traditional diagnostic methods with PCR-basedassay for the diagnosisof human brucellosis.

Two hundred sixty seven patients with symptoms of brucellosis were enrolled in this study.

For traditional methods a Rose Bengal Agglutination test (RBA) was performed and the Nova TEC Brucellaanti IgG and IgM Antibodies ELISA Test Kit has been designed for the detection and the quantitative determination of specific IgG and IgM antibodies against Brucella in serum.

DNA was extracted from patient samples using a genomic DNA purification kit.

Once the DNA was extracted, the RT- PCR was set up in a final volume of 20 µl with the Fast Start DNA Master SYBR Green I Kit.Seventy one cases were positive by PCR method, fifty one cases by ELISA and forty one cases by direct agglutination test (RBA).Sensitivity, specificity, positive prediction value, negative prediction value and diagnostic accuracy of brucella agglutination test in comparing with PCR were calculated as 53.52%, 89.66%, 92.68%, 44.07% and 64% respectively.Sensitivity, specificity, positive prediction value, negative prediction value and diagnostic accuracy of IgM antibodies by ELISA test in comparing with PCR were calculated as 45.07%, 96.55%, 96.97%, 41.79% and 60% respectively,while for IgG were calculated as 63.38%, 79.31%, 88.24%, 46.94% and 68% respectively.In Conclusion,the PCR method is more sensitive and specific than serological methods for the diagnosis of Brucella from peripheral blood samples in suspected cases.