Understanding and intervening in HIV-associated tuberculosis

The rapid molecular test Xpert MTB/RIF ultra: towards improved tuberculosis diagnosis and rifampicin resistance detection

BACKGROUND

Tuberculosis diagnosis has dramatically improved since the introduction of the rapid molecular test Xpert MTB/RIF (Xpert) detecting M. tuberculosis and rifampicin resistance directly from clinical specimens, therefore shortening the turnaround time, reducing patient's isolation period and decreasing the time to start anti-TB drugs. The new version, Xpert MTB/RIF Ultra (Ultra), displays a higher sensitivity and an improved rifampicin resistance detection. Both tests have been endorsed by the World Health Organisation.

AIMS

Xpert and Ultra rapidly became widespread and paved the way for new approaches and new paradigms as well as for the development of molecular point-of-care tests (POCTs). In this narrative review, we aimed to address their performance in the diagnosis of tuberculosis and to discuss the expectations of these tests as well as their limits and the unmet needs.

SOURCES

Peer-reviewed publications addressing the diagnostic performance of Ultra and Xpert.

CONTENT

We focused on publications that evaluated the performance of Ultra and Xpert on the same group of patients or the same set of specimens in different tuberculosis-burden settings.

IMPLICATIONS

The studies published so far reported an increased sensitivity of Ultra when compared to Xpert, which represents a benefit for tuberculosis diagnosis. The fact that such a sensitive assay cannot distinguish between alive and dead bacilli emphasizes that caution should be exercised regarding indications and interpretation of results. Additional studies are needed to determine the true performance for the diagnosis of extrapulmonary tuberculosis because of the great diversity of the specimens.

[Latent tuberculosis infection in persons with HIV/AIDS, associated factors, and progression to active disease in a city in southern Brazil]

The study proposed to identify the prevalence of latent tuberculosis infection (LTBI) in persons living with HIV/AIDS (PLWHA), associated factors, and progression to active tuberculosis among the identified cases. This was an epidemiological and descriptive study. The study population consisted of PLWHA seen from 2003 and 2014 in a reference center for HIV/AIDS. Data were collected from patient files and the Brazilian Information System for Notifiable Diseases (SINAN). Bivariate statistical analysis used the chi-square test in which variables with p < 0.2 were selected to enter the multiple regression model. Type I error was set at 5% (p < 0.05) for all the tests. In the study, 690 cases were analyzed, and 66 (9.4%) had a diagnosis of LTBI, with a prevalence of 7.5 cases per 100 patients. Of the 53 cases (80.3%) of LTBI who were prescribed treatment with isoniazid, only 26 (39.4%) concluded treatment, and 10 (15.1%) dropped out. Male gender (adjusted OR = 1.8; 95%CI: 1.1-3.3), current incarceration (adjusted OR = 7.6; 95%CI: 2.35-24.9), and high lymphocyte count were associated with LTBI diagnosis (adjusted OR = 1.1; 95%CI: 1.1-1.2). Forty-seven (6.7%) of LTBI cases progressed to active TB. Diagnosis and treatment of LTBI in PLWHA were not prioritized, which contributed to the development of active disease among cases. The study contributed to knowledge on LTBI in PLWHA, demonstrating crucial aspects in the management of PLWHA and the importance of detecting LTBI and early initiation of isoniazid, aimed at improved quality of life and prognosis for PLWHA.

Early diagnosis and effective treatment regimens are the keys to tackle antimicrobial resistance in tuberculosis (TB): A report from Euroscicon's international TB Summit 2016

To say that tuberculosis (TB) has regained a strong foothold in the global human health and wellbeing scenario would be an understatement. Ranking alongside HIV/AIDS as the top reason for mortality due to a single infectious disease, the impact of TB extends far into socio-economic context worldwide. As global efforts led by experts and political bodies converge to mitigate the predicted outcome of growing antimicrobial resistance, the academic community of students, practitioners and researchers have mobilised to develop integrated, inter-disciplinary programmes to bring the plans of the former to fruition. Enabling this crucial requirement for unimpeded dissemination of scientific discovery was the TB Summit 2016, held in London, United Kingdom. This report critically discusses the recent breakthroughs made in diagnostics and treatment while bringing to light the major hurdles in the control of the disease as discussed in the course of the 3-day international event. Conferences and symposia such as these are the breeding grounds for successful local and global collaborations and therefore must be supported to expand the understanding and outreach of basic science research.