Standardization and evaluation of a duplex real-time quantitative PCR for the detection of Leishmania infantum DNA: a sample quality control approach

• Published in: Revista da Sociedade Brasileira de Medicina Tropical
• Main Authors: Lays Adrianne Mendonça Trajano-Silva, Rômulo Pessoa-e-Silva, Suênia da Cunha Gonçalves-de-Albuquerque, Rayana Carla Silva de Morais, Cíntia Nascimento da Costa-Oliveira, Tayná Correia de Goes, Milena de Paiva-Cavalcanti
• Format: Article in Journal/Newspaper
• Language: English
• Published: Sociedade Brasileira de Medicina Tropical (SBMT)
• Subjects: Visceral leishmaniasis; Diagnosis; HIV/VL co-infection; Sample quality control; Duplex qPCR; Arctic medicine. Tropical medicine; RC955-962; Arctic
• Online Access: https://doi.org/10.1590/0037-8682-0012-2017; https://doaj.org/article/5b029d485da84d7d97cb60778a43fb36

Abstract INTRODUCTION: Molecular techniques have been shown to be alternative methods for the accurate detection of infectious and parasitic diseases, such as the leishmaniases. The present study describes the optimization and evaluation of a duplex real-time quantitative PCR (qPCR) protocol developed for the simultaneous detection of Leishmania infantum DNA and sample quality control. METHODS: After preliminary tests with the newly designed TaqMan® probes for the two targets ( L. infantum and glyceraldehyde 3-phosphate dehydrogenase (G3PD) gene), the duplex qPCR protocol was optimized. For the evaluation of the standardized protocol, human blood samples were tested (n=68) and the results were compared to those obtained by reference diagnostic techniques. Statistical analyses included percentage agreement and the Kappa ( k ) coefficient. RESULTS: The detection limit of L. infantum DNA reached 2x10 2 fg (corresponding to ~1 parasite) per µL of blood (ε: 93.9%). The percentage agreement obtained between the duplex VL qPCR and the reference techniques was individually obtained as follows: molecular: 88.3% ( k =0.666; 95% CI 0.437-0.894, good), and serological: 81.7% ( k =0.411; 95% CI 0.125-0.697, moderate). Between the reference techniques, the percentage agreement was 86.7% ( k =0.586; 95% CI 0.332-0.840, moderate). CONCLUSIONS: The new duplex VL qPCR protocol indicated good potential for the accurate, fast, and reliable detection of L. infantum DNA, when applied as a complement to the classical diagnostic tools already available, especially in health or research reference centers.