A recently publication in the journal Clinical Infectious Diseases is catching attention. The Xpert® MTB/RIF cycle threshold value predicts M. tuberculosis transmission to close contacts in a Brazilian prospective multicenter cohort was published by the RePORT-Brazil consortium, with authorship being led by the team at the Fundação de Medicina Tropical in Manaus, Amazonas, Brazil.
Below you will find an excerpt from an interview with Dr. Marcelo Cordeiro-Santos MD, PhD, Principal Investigator at the Fundação de Medicina Tropical.
Q: Dr. Cordeiro-Santos, can you tell us more about the purpose of the research?
A: The study aimed to determine whether the cycle threshold (Ct) values obtained from the Xpert® MTB/RIF test in pulmonary tuberculosis (TB) patients could be used to predict the risk of transmitting Mycobacterium tuberculosis (Mtb) to close contacts. This is important because understanding factors that influence TB transmission can aid in developing more effective infection control strategies. The study was carried out because there was no prior evidence that the Ct result could predict transmission, despite Xpert being recommended as the TB diagnostic test of choice by the WHO.
Q: What are some of the article's key findings and what is their importance in TB transmission?
A: The research found that lower Ct values in pulmonary TB patients were associated with a higher likelihood of TB infection in their close contacts, as indicated by baseline positivity and conversion of QuantiFERON (QFT)-Plus test results from negative to positive. This is significant because it suggests that Ct values could be a valuable marker for assessing the risk of TB transmission. Such information can be crucial in managing TB cases and preventing the spread of the disease, especially in high-risk settings.
Q: Based on this research, what are some of the future directions that can be explored?
A: Based on these findings, future research could explore the development of more targeted infection control measures that consider the Ct values of TB patients. This might include adjusting isolation protocols or monitoring strategies for contacts of patients with low Ct values. Additionally, further studies could investigate the biological mechanisms behind the observed association between Ct values and transmission risk, potentially leading to new therapeutic or preventive strategies against TB.