[Budget impact of the incorporation of GeneXpert MTB/RIF for diagnosis of pulmonary tuberculosis from the perspective of the Brazilian Unified National Health System, Brazil, 2013-2017]

How has the municipal availability of the GeneXpert®MTB/RIF system affected the detection of drug-resistant tuberculosis in Brazil?

OBJECTIVE

To evaluate the association between the availability of GeneXpert®MTB/RIF in municipalities and the proportion of people who have access to this diagnostic technology for tuberculosis (TB), as well as the resistance detected by the surveillance system in Brazil.

METHODS

We analysed 4998 Brazilian municipalities that reported 432,937 new TB cases between 2015 and 2020. We compared municipalities with and without the availability of GeneXpert®MTB/RIF regarding the effective access to GeneXpert®MTB/RIF diagnosis and the prevalence of detected resistance.

RESULTS

Municipalities with at least one GeneXpert®MTB/RIF system had three times (95% CI 2.9-3.0) the access to diagnostic tests and 80.4% (95% CI 70.6%-90.2%) higher detection of resistance, compared with municipalities without this technology. We estimated that there have been 1890 cases of undetected resistance during this period in the country.

CONCLUSIONS

The availability of GeneXpert®MTB/RIF system in the municipality increased the sensitivity of the surveillance for detecting TB resistance.

PUBLIC HEALTH IMPLICATIONS

It is a priority to strengthen laboratory networks and narrow the gap in access to rapid diagnosis in remote areas to improve the detection and control of drug-resistant tuberculosis.

The Value of GeneXpert MTB/RIF for Detection in Tuberculosis: A Bibliometrics-Based Analysis and Review

With the continuous development of medical science and technology, especially with the advent of the era of precision diagnosis and treatment, molecular biology detection technology is widely valued and applied as an aid to early diagnosis of tuberculosis. The GeneXpert Mycobacterium tuberculosis Branching (MTB) technology is a suite of semi-nested real-time fluorescent quantitative PCR in vitro diagnostic technologies developed by Cepheid Inc. It targets the rifampicin resistance gene, rpoB, and can detect both MTB and resistance to rifampicin within 2 h. This review analyzed the papers related to GeneXpert using bibliometric software CiteSpace and Bibliometrix. A total of 151 articles were analyzed, spanning from 2011 to 2021. This bibliometrics-based review summarizes the history of the development of GeneXpert in tuberculosis diagnosis and its current status. Contributions of different countries to the topic, journal analysis, key paper analysis, and clustering of keywords were used to analyze this topic.

Fast, simple and cheap: method modified from conventional cultivation for tuberculosis diagnosis allows seeding on Löwenstein-Jensen of any swab-embedded pulmonary samples decontaminated with sodium hydroxide

Background

Few tuberculosis (TB) control programmes in low-income countries have access to culture facilities in their primary care diagnostic centres and this scenario may have worsened with the coronavirus disease 2019 pandemic. Thus the aim was to develop and evaluate a simpler TB test that allows seeding on Löwenstein–Jensen (LJ) medium of several swab-embedded samples decontaminated with sodium hydroxide (NaOH).

Methods

A cotton swab containing each sample was decontaminated in NaOH before being dipped into a slightly acidic solution to neutralize the pH in order to allow the culture to develop on LJ medium. Samples (n=543) from suspected or confirmed pulmonary TB were analysed in two phases: standardization (n=167) and evaluation of the study method (n=376).

Results

The study method showed sensitivity >95% and specificity >93% using Ogawa–Kudoh (OK) and modified Petroff (MP) as standards and was comparable to MP-LJ (p>0.05) and slightly superior to OK (p=0.03) for sputum culture and more comprehensive than the latter for other pulmonary specimens.

Conclusions

This article reports a more comprehensive, simpler and less costly method for diagnosing TB in the laboratory with fewer economic resources and biosafety equipment. Thus a patent application was filed (BR1020190103841).

Impact of the GeneXpert® MTB/RIF rapid molecular test on tuberculosis detection: temporal trends and vulnerable territories

OBJECTIVE

to assess the impact of the GeneXpert® MTB/RIF rapid molecular test on tuberculosis detection, to analyze the temporal trend of the event and to identify vulnerable territories in a Brazilian municipality.

METHOD

an ecological study carried out in Ribeirão Preto, São Paulo, Brazil, a municipality considered a priority in tuberculosis control due to the high number of cases. To classify the temporal trend, the Prais-Winsten method and the Interrupted Time Series were used to identify changes in the disease incidence. Kernel intensity analysis was applied to identify vulnerable areas.

RESULTS

the temporal trend of tuberculosis decreased by 18.1%/year and by 6.9%/year for children under 15 years old. The North District decreased by 6.67%/year and the East District increased by 17.5%/year in the incidence of tuberculosis. Resistant tuberculosis, after the implementation of the Rapid Molecular Test, increased by 0.6% per year. The South and West Districts showed a higher density of cases, with a range from 45 to 79 tuberculosis cases per square kilometer (km2).

CONCLUSION

although resistant tuberculosis is not a problem in the scenario, the study showed an increase in its incidence, which puts it on alert. The use of spatial analysis enabled the identification of priority areas, putting them in evidence for health surveillance actions.

The fourth national anti-tuberculosis drug resistance survey in Peru

BACKGROUND: Peru has one of the highest burdens of multidrug-resistant tuberculosis (MDR-TB), but universal drug susceptibility testing (DST) has not yet been achieved.OBJECTIVE: To estimate the proportion of drug resistance among smear-positive TB patients in Peru.DESIGN: From September 2014 to March 2015, we performed a national drug resistance survey of patients aged ≥15 years; TB was diagnosed based on sputum smear positivity. We performed DST at the National Reference Laboratory of the Peruvian National Institute of Health, Lima, Peru, using the proportion method in Middlebrook 7H10 agar for four first-line drugs and six second-line drugs, and the Wayne method for pyrazinamide.RESULTS: Of the 1908 new and 272 previously treated patients included in the analysis, 638 (29.3%) patients had resistance to at least one first-line drug. MDR-TB was diagnosed in 7.3% of new and 16.2% of previously treated patients (P < 0.001). There were five (0.2%) patients with extensively drug-resistant TB.CONCLUSION: MDR-TB has increased to 7.3% in new patients from 5.3% in the previous survey, indicating that resistance to anti-tuberculosis drugs is increasing in Peru. Ongoing community transmission of resistant strains highlights an urgent need for early diagnosis, optimised treatment and effective contact tracing of MDR-TB patients.

Cost analysis of smear microscopy and the Xpert assay for tuberculosis diagnosis: average turnaround time

INTRODUCTION

Rapid and accurate tuberculosis detection is critical for improving patient diagnosis and decreasing tuberculosis transmission. Molecular assays can significantly increase laboratory costs; therefore, the average time and economic impact should be evaluated before implementing a new technology. The aim of this study was to evaluate the cost and average turnaround time of smear microscopy and Xpert assay at a university hospital.

METHODS

The turnaround time and cost of the laboratory diagnosis of tuberculosis were calculated based on the mean cost and activity based costing (ABC).

RESULTS

The average turnaround time for smear microscopy was 16.6 hours while that for Xpert was 24.1 hours. The Xpert had a mean cost of USD 17.37 with an ABC of USD 10.86, while smear microscopy had a mean cost of USD 13.31 with an ABC of USD 6.01. The sensitivity of smear microscopy was 42.9% and its specificity was 99.1%, while the Xpert assay had a sensitivity of 100% and a specificity of 96.7%.

CONCLUSIONS

The Xpert assay has high accuracy; however, the turnaround time and cost of smear microscopy were lower than those of Xpert.

Early death by tuberculosis as the underlying cause in a state of Southern Brazil: Profile, comorbidities and associated vulnerabilities

AIM

To know the profile of adults who died by tuberculosis as the main cause, the time interval between the diagnosis and death, associated comorbidities and vulnerabilities.

METHOD

Observational study of secondary data regarding deaths by tuberculosis that occurred in the State of Paraná, Brazil, from 2008 to 2015. A linkage between the databases of mortality and tuberculosis notification system was conducted for data enrichment. Frequency tables, Exact Fisher test and Z test have identified statistical associations.

RESULTS

Linkage points out 12.1% (115/944) of under-reporting in the 944 deaths identified. Early deaths accounted for 74.6% (705/944). The male sex (75.8%) was associated with the early death group. Almost half of the deaths reported in notification system (414/829) had one or more vulnerabilities. Early death were associated with respiratory system diseases and symptoms (p=0.0001) and mental and behavioral disorders (p=0.0001).

CONCLUSION

High number of early deaths due TB indicate the need to seek out the respiratory symptomatic and use faster diagnostic methods. Strategies for treatment adherence, adequate monitoring of comorbidities and multisectorial support may prevent early and late death. The presence of vulnerabilities indicates that efforts beyond the health sector are needed in order to eliminate tuberculosis as public health problem.