Monitoring the parasite load in chronic Chagas disease patients: comparison between blood culture and quantitative real time PCR

• Published in: PloS one Vol. 13; no. 11; p. e0208133
• Main Authors: D'Ávila, Daniella Alchaar, Galvão, Lúcia Maria C, Sousa, Giovane R, Britto, Constança, Moreira, Otacilio C, Chiari, Egler
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29.11.2018; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Aged, 80 and over; Biology and Life Sciences; Blood; Blood circulation; Blood Culture; Blood tests; Cardiomyopathy; Chagas disease; Chagas Disease - blood; Chagas Disease - parasitology; Culture; Deoxyribonucleic acid; Development strategies; Diagnosis; Diagnostic software; Diagnostic systems; DNA; DNA, Protozoan - analysis; DNA, Protozoan - genetics; Family medical history; Female; Humans; Infections; Laboratories; Load distribution; Male; Medical diagnosis; Medicine and Health Sciences; Middle Aged; Monitoring; Multiplexing; Myocardial diseases; Parasite Load; Parasites; Patients; Polymerase chain reaction; Protozoa; Real time; Real-Time Polymerase Chain Reaction; Research and Analysis Methods; Risk factors; Statistical methods; Technology; Technology assessment; Trypanosoma cruzi; Trypanosoma cruzi - genetics; Trypanosoma cruzi - isolation & purification; Trypanosomiasis; Vector-borne diseases; Young Adult; Hoboken New Jersey; Brazil; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0208133

Despite the improvements in diagnostic tools for detection of Trypanosoma cruzi in human blood samples, the isolation of parasite from bloodstream in the chronic phase of Chagas disease is challenging. Thus, there is an increasing interest in the development of strategies that allow an accurate monitoring of the parasite load in bloodstream of Chagas disease patients. Given that, the comparison of a classical diagnostic method such as blood culture and multiplex quantitative real-time PCR (qPCR) was few explored so far. Therefore, this study aimed to compare the detection and quantification of T. cruzi load in the circulating blood of patients with chronic Chagas disease, using blood culture and qPCR techniques. The multiplex real-time quantitative PCR assay (qPCR) based on TaqMan technology was evaluated in 135 blood samples from 91 patients with chronic Chagas disease presenting indeterminate (asymptomatic, n = 23) and cardiac (chronic cardiomyopathy, n = 68) forms, in comparison with the classical blood culture (BC) technique. The total positivity of qPCR and BC was 58.5% and 49.6%, respectively. The median parasite load of all positive patients was 1.18 [0.39-4.23] par. eq.⁄mL, ranging from 0.01 to 116.10 par. eq.⁄mL. We did not find significant differences between T. cruzi load with age and distinct clinical manifestations of patients. Our data suggest that qPCR can be an auxiliary tool for studies that require T. cruzi isolation from the bloodstream of patients with chronic Chagas disease, after the establishment of a parasite load cut-off that guarantees a relative success rate of parasite isolation using BC technique.