Dados do Trabalho

Título

Detection of Mycobacterium tuberculosis DNA by qPCR at the point of care: performing screening within the penitentiary system

Introdução

Data from the World Health Organization indicate that approximately one third of the global population is infected by Mycobacterium tuberculosis, the causative agent of tuberculosis (TB). Populations in vulnerable situations are the most affected, such as those deprived of their liberty. In fact, due to overcrowding, TB prevalence in Brazilian penitentiaries is almost double that of the population. 

Objetivo (s)

In this work, we used a complete molecular test, already optimized in a laboratory environment, for screening of prisoners serving their sentence at the Venâncio Aires State Penitentiary (PEVA, Venâncio Aires, RS) in search for detection of M. tuberculosis DNA. 

Material e Métodos

The portable qPCR-based platform allows for onsite performance of the molecular test, thus avoiding removing the prisoner from the penitentiary environment. The platform consists of a simplified DNA extraction method from sputum samples followed by a qPCR assay carried out on a portable equipment, with a total ‘sample-to-answer” of less than 4 hours. All reagents, consumables and instruments fit in a regular food-delivery box, in line with the desired portability of the platform. qPCR reagents were preserved in a gelified solution and preloaded onto the chips, allowing for storage at 2-8 °C. 

Resultados e Conclusão

Forty-eight inmates with TB symptoms or who shared a cell with symptomatic individuals were selected for sputum collection. Samples were immediate processed by the simplified DNA extraction method and qPCR assay to detect the IS6110 genomic marker. Of the 48 samples, 3 were positive for M. tuberculosis DNA by the molecular test, while only 1 of them was also positive in sputum smear microscopy. All 3 samples await confirmatory culture testing. These results demonstrate the feasibility of performing a complete and truly portable molecular test for tuberculosis screening directly at the point of care. The platform is not intended for routine use, but rather to provide access for vulnerable populations, or populations in remote locations, to more sensitive and specific diagnostic tests. This access would allow early detection of TB-positive patients by the health system, with earlier onset of treatment, thus helping to break the chain of disease transmission.

Palavras Chave

Tuberculosis; Prison system; point of care.