Large-scale evaluation of a single-tube nested PCR for the laboratory diagnosis of human brucellosis in Kuwait

Abstract

A single-tube nested PCR assay identifying a 52 bp fragment from the genus-specific Brucella IS711 gene was used prospectively in clinical practice for the diagnosis of human brucellosis in Kuwait. Patients with suspected brucellosis and with other infections were investigated as clinically indicated but in all of them culture, serology and PCR for Brucella were carried out. Out of 263 suspected cases of brucellosis, diagnostic tests were positive in 199, serology was positive in 199 and culture in 89, while the Brucella PCR was positive in 193 (sensitivity 96 . 98 %, 95 % confidence interval 94 . 5-99 . 5 %). Chronic brucellosis, involving symptoms for more than 1 year, was diagnosed in 49 out of these 193 patients. Diagnoses in four out of the six patients with positive serology but negative PCR and culture were non-Brucella bacterial meningitis and viral meningitis. False-negative PCR results were possible in the remaining two; both had been on long-term antibiotics for previously diagnosed brucellosis but their adherence may have been questionable, allowing a relapse. The PCR was negative in 244 patients with other infections (specificity 100 %) and in 180 control subjects with negative Brucella culture and serology. PCR results were available within 24 h of sample receipt, providing diagnostic information rapidly. The PCR is expensive and technically demanding and may not be appropriate for all cases. Future studies will help define how it may best be used. For example Brucella and tuberculous meningitides can be very similar, Brucella PCR may allow prompt distinction between the two, avoiding the need for prolonged empirical treatment for both.

Polymerase Chain Reaction–Based Assays for the Diagnosis of Active and Relapsed Cases of Human Brucellosis

“…This high sensitivity suggests that the PCR method may replace blood culture as the gold standard for the diagnosis of acute brucellosis. [29][30][31] Our results are similar to the finding of other researchers reporting that the species-specific PCR assay with primers IS711 can detect B. melitensis DNA in both SAT-positive and negative samples. The sensitivity and specificity of PCR-IS711 compared with SAT as the gold standard were found to be between 80% and 98% by other researchers.…”

Utility of Serological Tests in the Era of Molecular Testing for Diagnosis of Human Brucellosis in Endemic Area with Limited Resources

“…Another very important reason could be that population in brucellosis endemic area may have normally elevated high titers of antibodies. In studies from many middle-east countries, Spain and Greece, where also the disease is endemic, cut-off values for considering active infection are higher (≥320 I.U) than of 80 IU/ml taken in the present study [9,14,15].…”

Hypothermia with Pneumonia: A Rare Presentation of Brucellosis

“…Four species of Brucella can cause human disease: B. melitensis, B. abortus, B. suis, and B. canis [1] . Infection with B. melitensis accounts for the vast majority of cases worldwide as well as in Kuwait [1,4] . Clinical disease is common in the Middle East and Asia [2] .…”