New anti-SARS-CoV-2 aminoadamantane compounds as antiviral candidates for the treatment of COVID-19

Here, the antiviral activity of aminoadamantane derivatives were evaluated against SARS-CoV-2. The compounds exhibited low cytotoxicity to Vero, HEK293 and CALU-3 cells up to a concentration of 1,000 µM. The inhibitory concentration (IC50) of aminoadamantane was 39.71 µM in Vero CCL-81 cells and the derivatives showed significantly lower IC50 values, especially for compounds 3F4 (0.32 µM), 3F5 (0.44 µM) and 3E10 (1.28 µM). Additionally, derivatives 3F5 and 3E10 statistically reduced the fluorescence intensity of SARS-CoV-2 protein S from Vero cells at 10 µM. Transmission microscopy confirmed the antiviral activity of the compounds, which reduced cytopathic effects induced by the virus, such as vacuolization, cytoplasmic projections, and the presence of myelin figures derived from cellular activation in the face of infection. Additionally, it was possible to observe a reduction of viral particles adhered to the cell membrane and inside several viral factories, especially after treatment with 3F4. Moreover, although docking analysis showed favorable interactions in the catalytic site of Cathepsin L, the enzymatic activity of this enzyme was not inhibited significantly in vitro. The new derivatives displayed lower predicted toxicities than aminoadamantane, which was observed for either rat or mouse models. Lastly, in vivo antiviral assays of aminoadamantane derivatives in BALB/cJ mice after challenge with the mouse-adapted strain of SARS-CoV-2, corroborated the robust antiviral activity of 3F4 derivative, which was higher than aminoadamantane and its other derivatives. Therefore, aminoadamantane derivatives show potential broad-spectrum antiviral activity, which may contribute to COVID-19 treatment in the face of emerging and re-emerging SARS-CoV-2 variants of concern.

Analysis of catastrophic costs incurred by patients with multidrug-resistant tuberculosis in an outpatient clinic in the state of Rio de Janeiro

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) is a serious global public health concern associated with social vulnerability. In Brazil, the Unified Health System (SUS, Portuguese) provides free diagnosis and treatment for MDR-TB; however, other expenses may still be incurred for patients and their families which, according to the World Health Organization (WHO), can be catastrophic when these costs surpass 20.0% of the annual household income. This study aimed to assess the extent of catastrophic costs related to the diagnostic and therapeutic aspects of MDR-TB among patients receiving care at an outpatient clinic in Rio de Janeiro.

METHODS

This prospective study used convenience sampling from July 2019 to June 2021. Data regarding direct and indirect costs were collected using a standardized questionnaire endorsed by the WHO. To analyze any impoverishment occurred from MDR-TB, a threshold established by the Brazilian Institute of Geography and Statistics for 2019 and 2020 of US$ 79,562 and US$ 94,5273, respectively, was applied. Descriptive statistics were used for data analysis, including mean; standard deviation; variation coefficient; median; and maximum, minimum, and interquartile ranges.

RESULTS

A total of 65 patients were interviewed. Among the participants, 73.8% experienced catastrophic costs, with indirect costs exerting the most significant impact (median: US$ 3,825.9), in contrast to direct costs (median: US$ 542.7). When comparing the periods before and after diagnosis, the prevalence of poverty increased from 12.0% to 28.0%.

CONCLUSIONS

Despite the support from the SUS in Brazil, diagnostic and therapeutic cascades incur additional costs, exacerbating social vulnerability among patients with MDR-TB.

Nontuberculous mycobacteria in patients of a specialty hospital

The incidence and clinical characteristics of NTM diseases in Brazil remain relatively unknown. The present study describes the diagnosis of NTM isolates, the clinical presentation and treatment outcomes. We analyzed NTM isolates in patients of a tertiary hospital in the Southeast region of Brazil, from January 2008 to July 2019. The ATS/IDSA criteria for diagnosis and treatment of these patients was applied. Mycobacterium kansasii were identified in 13/113 (11.5%) patients. In 59/113 (52.2%) patients who met the ATS criteria for disease, 29/59 (49.1%) received treatment, and 22/29 (75.8%) were cured. The major species identified was M. kansasii. The most frequent symptoms among the treated patients were dyspnea and cough, and the proportion of cured patients was high.

Serum biomarkers in patients with unilateral or bilateral active pulmonary tuberculosis: Immunological networks and promising diagnostic applications

The present observational study was designed to characterize the integrative profile of serum soluble mediators to describe the immunological networks associated with clinical findings and identify putative biomarkers for diagnosis and prognosis of active tuberculosis. The study population comprises 163 volunteers, including 84 patients with active pulmonary tuberculosis/(TB), and 79 controls/(C). Soluble mediators were measured by multiplexed assay. Data analysis demonstrated that the levels of CCL3, CCL5, CXCL10, IL-1β, IL-6, IFN-γ, IL-1Ra, IL-4, IL-10, PDGF, VEGF, G-CSF, IL-7 were increased in TB as compared to C. Patients with bilateral pulmonary involvement/(TB-BI) exhibited higher levels of CXCL8, IL-6 and TNF with distinct biomarker signatures (CCL11, CCL2, TNF and IL-10) as compared to patients with unilateral infiltrates/(TB-UNI). Analysis of biomarker networks based in correlation power graph demonstrated small number of strong connections in TB and TB-BI. The search for biomarkers with relevant implications to understand the pathogenetic mechanisms and useful as complementary diagnosis tool of active TB pointed out the excellent performance of single analysis of IL-6 or CXCL10 and the stepwise combination of IL-6 → CXCL10 (Accuracy = 84 %; 80 % and 88 %, respectively). Together, our finding demonstrated that immunological networks of serum soluble biomarkers in TB patients differ according to the unilateral or bilateral pulmonary involvement and may have relevant implications to understand the pathogenetic mechanisms involved in the clinical outcome of Mtb infection.

Sociodemographic and Clinical Factors Associated with Treatment Outcomes for Drug-resistant Tuberculosis

Drug-resistant tuberculosis (DR-TB) continues to be a serious public health problem. The objective of this study was to evaluate the sociodemographic, radiological, clinical, and outcome characteristics and assess the determinants of unfavorable outcomes in DR-TB. The descriptive-analytical study was carried out in a reference outpatient clinic in Rio de Janeiro, Brazil, among DR-TB cases that received treatment between February 2016 and October 2020, using descriptive statistics, χ2 test, and logistic regression multivariate. Of the 148 cases, 12.2% were resistant to rifampicin, 12.2% were resistant to isoniazid, 18.2% were polyresistant, 56.1% multidrug resistant, and 1.3% were extensively drug resistant. Most of the patients were men, aged up to 44 years, with brown or black skin, having up to 8 years of schooling, unemployed or working in the informal economy, and of low income. Presenting with acquired resistance or positive sputum smear microscopy in the diagnosis, taking more than four drugs, and being unemployed were associated with unfavorable outcomes. Having no income or acquired resistance doubled the chances of unfavorable outcomes. There was a high proportion of unfavorable outcomes, thereby highlighting the need to concentrate efforts on planning and executing public policies that include the severity of DR-TB and its risk factors.

Impact of a computer system as a triage tool in the management of pulmonary tuberculosis in a HIV reference center in Brazil

Background:

The Neural Clinical Score for tuberculosis (NCS-TB) is a computer system developed to improve the triage of presumed pulmonary TB (pPTB).

Methods:

A study was performed with cohorts of pPTB patients cared for at a reference hospital in Northeast Brazil.

Results:

The NCS-TB sensitivity was 76.5% for TB diagnosis, which shortened the time from triage to smear microscopy results (3.3 to 2.5 days; p<0.001) and therapy initiation (6.7 to 4.1 days; p=0.045).

Conclusions:

Although the NCS-TB was not suitable as a screening tool, it was able to optimize laboratory diagnosis and shorten the time to treatment initiation.

Molecular characterization of nontuberculous Mycobacteria in a tuberculosis and HIV reference unit in the State of Amazonas, Brazil

BACKGROUND

In recent years, the prevalence of nontuberculous mycobacterial (NTM) infections has increased in different regions of the world. The American Thoracic Society (ATS) recommends standardized identification criteria, reinforcing the need for faster and less complicated clinical and laboratory techniques.

METHODS

In this retrospective study, NTM species isolated from pulmonary, extrapulmonary, and disseminated samples from patients treated at a TB/HIV reference unit in the State of Amazonas from 2011 to 2014 were identified through a combination of molecular techniques.

RESULTS

To identify the molecular technique, 50 cryopreserved NTM cultures were recovered and subcultivated in culture medium. The potentially pathogenic NTM species identified were M. avium, M. intracellulare, M. kansasii, M. chelonae, M. abscessus, M. fortuitum, and M. peregrinum. Results of GenoType® showed moderate agreement with those of genomic sequencing (kappa = 0.60), whereas the results obtained by the PRA-hsp65 technique disagreed with the results obtained by sequencing (kappa = 0.49).

CONCLUSIONS

Our findings highlight that GenoType CM is a good method for the identification of NTM, as well as the need for the application of standardized criteria, such as those set forth by the ATS.

Clinical Impact of the Line Probe Assay and Xpert® MTB/RIF Assay in the Presumptive Diagnosis of Drug-Resistant Tuberculosis in Brazil: A Pragmatic Clinical Trial

Background:

Rapid molecular methods such as the line probe assay (LPA) and Xpert^® MTB/RIF assay (Xpert) have been recommended by the World Health Organization for drug-resistant tuberculosis (DR-TB) diagnosis. We conducted an interventional trial in DR-TB reference centers in Brazil to evaluate the impact of the use of LPA and Xpert.

Methods:

Patients with DR-TB were eligible if their drug susceptibility testing results were available to the treating physician at the time of consultation. The standard reference MGIT^TM 960 was compared with Xpert (arm 1) and LPA (arm 2). Effectiveness was considered as the start of the appropriate TB regimen that matched drug susceptibility testing (DST) and the proportions of culture conversion and favorable treatment outcomes after 6 months.

Results:

A higher rate of empirical treatment was observed with MGIT alone than with the Xpert assay (97.0% vs. 45.0%) and LPA (98.2% vs. 67.5%). Patients started appropriate TB treatment more quickly than those in the MGIT group (median 15.0 vs. 40.5 days; p<0.01) in arm 1. Compared to the MGIT group, culture conversion after 6 months was higher for Xpert in arm 1 (90.9% vs. 79.3%, p=0.39) and LPA in arm 2 (80.0% vs. 83.0%, p=0.81).

Conclusions:

In the Xpert arm, there was a significant reduction in days to the start of appropriate anti-TB treatment and a trend towards greater culture conversion in the sixth month.

Cost analysis for patients with presumed pulmonary tuberculosis attended in the public health system of rio de janeiro, Brazil

Background

In last years, few attention has given to the patient's prediagnostic costs when evaluating the introduction of new technologies for tuberculosis (TB) and in this context, this study evaluated patient's costs and cost-effectiveness incurred with TB diagnosis comparing Bactec^TMMGIT^TM960 system (MGIT) to the Löwestein-Jensen (LJ) culture in a health center and in a university hospital, in Rio de Janeiro City, Brazil.

Methods

Patient's mean costs were evaluated during the diagnosis process and cost-effectiveness based on mean time in days for the adoption of appropriate clinical anti-TB treatment in two health units comparing culture by means LJ and MGIT.

Results

The mean cost of LJ and MGIT in the health center was U. S. dollars (US$) 26.6 and US$ 45.13, respectively, and in university hospital was US$ 206.87 and US$ 285.48, respectively. Comparing the two approaches for TB diagnosis incurred by the patients, the incremental cost-effectiveness of MGIT compared to LJ was US$ 0.88 and US$ 4.03 per patient, respectively, to reduce the average time to adopt appropriate treatment.

Conclusions

The culture method directly impacts patient costs while waiting for the correct diagnosis and contributing to aggravating costs with patients with TB.

The impact of the stratification by degree of clinical severity and abandonment risk of tuberculosis treatment

Objective:

Evaluate the impact of the instrument of the “Stratification by Degree of Clinical Severity and Abandonment Risk of Tuberculosis Treatment” (SRTB) on the tuberculosis outcome.

Methods:

This study was a pragmatic clinical trial involving patients with a confirmed diagnosis of tuberculosis treated at one of the 152 primary health care units in the city of Belo Horizonte, Brazil, between May of 2016 and April of 2017. Cluster areas for tuberculosis were identified, and the units and their respective patients were divided into intervention (use of SRTB) and nonintervention groups.

Results:

The total sample comprised 432 participants, 223 and 209 of whom being allocated to the nonintervention and intervention groups, respectively. The risk of treatment abandonment in the nonintervention group was significantly higher than was that in the intervention group (OR = 15.010; p < 0.001), regardless of the number of risk factors identified. Kaplan-Meier curves showed a hazard ratio of 0.0753 (p < 0.001).

Conclusions:

The SRTB instrument was effective in reducing abandonment of tuberculosis treatment, regardless of the number of risk factors for that. This instrument is rapid and easy to use, and can be adapted to different realities. Its application showed characteristics predisposing to a non-adherence to the treatment and established bases to mitigate its impact.

Pulmonary functional assessment: longitudinal study after treatment of pulmonary tuberculosis

Even when treated adequately, pulmonary tuberculosis can lead to pulmonary sequelae. Patients treated for PTB between 2012 and 2016 answered a standardized questionnaire and underwent chest radiography and spirometry, measurement of absolute pulmonary volume, Diffusing Capacity for Carbon Monoxide (DLCO) and the 6-min walk test (6MWT) on two occasions: within the first year after the end of treatment (follow-up 1), and one and two years after follow-up 1 (follow-up 2). A total of 55 patients they underwent spirometry, 23 (41.82%) had obstructive ventilatory disorder (OVD) and eight (14.5%) had moderate OVD. In total, 29 patients underwent pulmonary function tests (PFTs) and 24 patients underwent the 6MWT on two occasions. The functional changes after PTB treatment appear not to have varied between one and two years of follow-up. There was a correlation between low FEV1 and low DLCO (p<0.001); low DLCO and low 6MWT (p<0.001) and radiographic abnormalities and low FEV1 (p=0.033). The most frequently observed change in spirometry was found in patients with OVD.

[Performance assessment of primary healthcare services in tuberculosis control in a city in Southeast Brazil]

The World Health Organization highlights the importance of health services organization and performance in tuberculosis (TB) control activities. This study aimed to assess the performance of primary healthcare services in Belo Horizonte, Minas Gerais State, Brazil, in TB control activities in the dimensions Structure and Process, before and after the use of a validated instrument called Stratification by Degree of Clinical Risk and Tuberculosis Treatment Dropout (ERTB). This was a descriptive and prospective study with two interviews (455 professionals), the second of which after the ERTB. Performance classification was: ≤ 49.9%, critical; 50-79.9%, unsatisfactory, and ≥ 80%, satisfactory. The comparative assessment used the McNemar statistical test with p < 0.05. After risk stratification, most of the variables in each dimension improved significantly. The authors conclude that it was possible to identify satisfactory performance in most of the variables assessed in the Structure and Process dimensions in primary healthcare services in Belo Horizonte in relation to TB control activities, using a standardized questionnaire.

Cost-effectiveness of Xpert®MTB/RIF in the diagnosis of tuberculosis: pragmatic study

INTRODUCTION

The intensification of research and innovation with the creation of networks of rapid and effective molecular tests as strategies for the end of tuberculosis are essential to avoid late diagnosis and for the eradication of the disease. We aimed to evaluate the cost-effectiveness of Xpert®MTB/RIF (Xpert) in the diagnosis of drug-resistant tuberculosis in reference units, in scenarios with and without subsidies, and the respective cost adjustment for today.

METHODS

The analyses were performed considering as criterion of effectiveness, negative culture or clinical improvement in the sixth month of follow-up. The comparison was performed using two diagnostic strategies for the drug susceptibility test (DST), BactecTMMGITTM960 System, versus Xpert. The cost effectiveness and incremental cost-effectiveness ratio (ICER) were calculated and dollar-corrected for American inflation (US$ 1.00 = R$ 5,29).

RESULTS

Subsidized Xpert had the lowest cost of US$ 33.48 (R$67,52) and the highest incremental average efficiency (13.57), thus being a dominated analysis. After the inflation was calculated, the mean cost was DST-MGIT=US$ 74.85 (R$ 396,73) and Xpert = US$ 37.33 (R$197,86) with subsidies.

CONCLUSIONS

The Xpert in the diagnosis of TB-DR in these reference units was cost-effective with subsidies. In the absence of a subsidy, Xpert in TB-DR is not characterized as cost effective. This factor reveals the vulnerability of countries dependent on international organizations' subsidy policies.

Characterization of Mycobacterium tuberculosis heteroresistance by genotyping

Background

Heteroresistance is the coexistence of susceptible and resistant strains in the same individual, considered the preliminary step for total resistance, and can stem from mixed infection or clonal heterogeneity. The aim of this study was to evaluate the heteroresistance of Mycobacterium tuberculosis to rifampicin and isoniazid and its characterization.

Method

GenoType MTBDRplus^®; Sanger sequencing of the rpoB, katG, and inhA genes; and Mycobacterial Interspersed Repetitive Unit - Variable Number Tandem Repeat (MIRU-VNTR) were performed.

Results

In a total of 654 isolates, 530 were resistant, 124 were susceptible, and 29 were heteroresistant to a first-line drug. GenoType MTBDRplus^® detected heteroresistance in the rpoB gene in 26/29 (89.6%), as compared to 5/29 (17.2%) in the katG gene and 2/29 (6.8%) in the inhA gene. Four isolates showed heteroresistance in these genes. The Sanger sequencing detected heteroresistance in the rpoB gene in 7/29 (24.1%), as compared to 3/29 (10.3%) in the katG gene. In one isolate, heteroresistance was concomitant in both the rpoB and katG genes. MIRU-VNTR detected mixed infection in three heteroresistant isolates, while four isolates showed clonal heterogeneity.

Conclusions

GenoType MTBDRplus^® detected more cases of heteroresistance when compared to sequencing. It was also possible to characterize mixed infection and clonal heterogeneity by MIRU-VNTR.

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.

The activity-based cost of drug-susceptibility test of Mycobacterium tuberculosis through Kit SIRE Nitratase® Plastlabor

Background

Drug-resistant tuberculosis (TB) is an ongoing health threat, and the greatest challenge to adequate control of TB in many countries lies in the lack of proper laboratory drug-susceptibility test. The aim of this study was to evaluate the activity-based costs (ABC) of Kit SIRE Nitratase^® (Kit SIRE) and compare its values with the conventional drug-susceptibility test.

Methods

The ABC was calculated for three different approaches: Kit SIRE (clinical samples and cultures), proportion methods in Lowenstein Jensen (PM-LJ), and the Bactec™ MGIT™ 960 system based on Mycobacterial Research Laboratory's routine.

Results

The ABC of Kit SIRE from cultures was US$ 148.54, while from clinical samples was US$ 136.12. In the case of conventional tests, the ABC of Bactec™ MGIT™ 960 was US$ 227.63 and of the PM-LJ was US$ 132.64. The Kit SIRE has a lower ABC when clinical samples are used instead of cultures. Compared to conventional tests, the ABC is similar to the PM-LJ and lower the Bactec™ MGIT™ 960.

Conclusion

The Kit SIRE should be used as a screening method in clinical specimens and in culture for laboratories that do not have Bactec™ MGIT™ 960. Therefore, it can be incorporated into the routine of laboratories in countries with low resources and a high burden of TB and drug-resistant TB.

Rapid detection of Mycobacterium tuberculosis DNA and genetic markers for Isoniazid resistance in Ziehl-Neelsen stained slides

BACKGROUND

Early diagnosis of tuberculosis (TB) and identification of strains of Mycobacterium tuberculosis resistant to anti-TB drugs are considered the main factors for disease control.

OBJECTIVES

To standardise a real-time polymerase chain reaction (qPCR) assay technique and apply it to identify mutations involved in M. tuberculosis resistance to Isoniazid (INH) directly in Ziehl-Neelsen (ZN) stained slides.

METHODS

Were analysed 55 independent DNA samples extracted from clinical isolates of M. tuberculosis by sequencing. For application in TB diagnosis resistance, 59 ZN-stained slides were used. The sensitivity, specificity and Kappa index, with a 95% confidence interval (CI95%), were determined.

FINDINGS

The agreement between the tests was, for the katG target, the Kappa index of 0.89 (CI95%: 0.7-1.0). The sensitivity and specificity were 97.6% (CI95%: 87.7-99.9) and 91.7% (CI95%: 61.5-99.5), respectively. For inhA, the Kappa index was 0.92 (CI95%: 0.8-1.0), the sensitivity and specificity were 94.4% (CI95%: 72.7-99.8) and 97.3% (CI95%: 85.8-99.9), respectively. The use of ZN-stained slides for drug-resistant TB detection showed significant results when compared to other standard tests for drug resistance.

MAIN CONCLUSIONS

qPCR genotyping proved to be an efficient method to detect genes that confer M. tuberculosis resistance to INH. Thus, qPCR genotyping may be an alternative instead of sequencing.

Mapping the tuberculosis scientific landscape among BRICS countries: a bibliometric and network analysis

BACKGROUND

The five BRICS (Brazil, Russian, Indian, China, and South Africa) countries bear 49% of the world's tuberculosis (TB) burden and they are committed to ending tuberculosis.

OBJECTIVES

The aim of this paper is to map the scientific landscape related to TB research in BRICS countries.

METHODS

Were combined bibliometrics and social network analysis techniques to map the scientific publications related to TB produced by the BRICS. Was made a descriptive statistical data covering the full period of analysis (1993-2016) and the research networks were made for 2007-2016 (8,366 records). The bubble charts were generated by VantagePoint and the networks by the Gephi 0.9.1 software (Gephi Consortium 2010) from co-occurrence matrices produced in VantagePoint. The Fruchterman-Reingold algorithm provided the networks' layout.

FINDINGS

During the period 1993-2016, there were 38,315 peer-reviewed, among them, there were 11,018 (28.7%) articles related by one or more authors in a BRICS: India 38.7%; China 23.8%; South Africa 21.1%; Brazil 13.0%; and Russia 4.5% (The total was greater than 100% because our criterion was all papers with at least one author in a BRICS). Among the BRICS, there was greater interaction between India and South Africa and organisations in India and China had the highest productivity; however, South African organisations had more interaction with countries outside the BRICS. Publications by and about BRICS generally covered all research areas, especially those in India and China covered all research areas, although Brazil and South Africa prioritised infectious diseases, microbiology, and the respiratory system.

MAIN CONCLUSIONS

An overview of BRICS scientific publications and interactions highlighted the necessity to develop a BRICS TB research plan to increase efforts and funding to ensure that basic science research successfully translates into products and policies to help end the TB epidemic.

Genotype®MTBDRplus and Xpert®MTB/RIF in the diagnosis of tuberculosis and resistant tuberculosis: cost analysis in a tertiary referral hospital

INTRODUCTION

The present study sought to assess the mean and activity based cost (ABC) of the laboratory diagnosis for tuberculosis through the application of conventional and molecular techniques-Xpert®MTB/RIF and Genotype®MTBDRplus-in a tertiary referral hospital in Brazil.

METHODS

The mean cost and ABC formed the basis for the cost analysis of the TB laboratory diagnosis.

RESULTS

The mean cost and ABC were US$ 4.00 and US$ 3.24, respectively, for a bacilloscopy; US$ 6.73 and US$ 5.27 for a Lowenstein-Jensen (LJ) culture; US$ 105.42 and US$ 76.56 for a drug sensitivity test (DST)-proportions method (PM) in LJ; US$ 148.45 and US$ 136.80 for a DST-BACTECTM MGITTM 960 system; US$ 11.53 and US$ 9.89 for an Xpert®MTB/RIF; and US$ 84.21 and US$ 48.38 for a Genotype®MTBDRplus.

CONCLUSIONS

The mean cost and ABC proved to be good decision-making parameters in the diagnosis of TB and MDR-TB. The effective implementation of algorithms will depend on the conditions at each location.

Mycobacterium abscessus subsp. bolletii keratitis: rare case reported in Brazil

In this report, we described a rare case of Mycobacterium abscessus subsp. bolletii keratitis in a young healthy male, in the absence of risk factors.

Factors associated with tuberculosis and multidrug-resistant tuberculosis in patients treated at a tertiary referral hospital in the state of Minas Gerais, Brazil

Objective:

To evaluate the risk factors for the development of tuberculosis and multidrug-resistant tuberculosis (MDR-TB) in patients treated at a tertiary referral hospital.

Methods:

This was a cross-sectional study based on data obtained from patients treated at the Júlia Kubitschek Hospital, located in the city of Belo Horizonte, Brazil, between October of 2012 and October of 2014. We evaluated sociodemographic, behavioral, clinical, and radiological variables. The outcome considered to identify associations between tuberculosis and the explanatory variables was the treatment prescribed. To evaluate the associations between MDR-TB and the same explanatory variables, the change in MDR-TB treatment was considered.

Results:

The factors associated with tuberculosis were alcoholism, comorbidities, pulmonary cavitations, and a radiological pattern suggestive of tuberculosis. Cavitation and previous treatment for tuberculosis were associated with MDR-TB.

Conclusions:

Despite the significant progress made in the fight against tuberculosis, there is a need for coordinated actions that include social protection measures and patient support.

Multicenter evaluation of TB-SPRINT 59-Plex Beamedex®: accuracy and cost analysis

Background

Molecular tests can allow the rapid detection of tuberculosis (TB) and multidrug-resistant TB (MDR-TB). TB-SPRINT 59-Plex Beamedex® is a microbead-based assay developed for the simultaneous spoligotyping and detection of MDR-TB. The accuracy and cost evaluation of new assays and technologies are of great importance for their routine use in clinics and in research laboratories. The aim of this study was to evaluate the performance of TB-SPRINT at three laboratory research centers in Brazil and calculate its mean cost (MC) and activity-based costing (ABC).

Methods

TB-SPRINT data were compared with the phenotypic and genotypic profiles obtained using Bactec™ MGIT™ 960 system and Genotype® MTBDRplus, respectively.

Results

Compared with MGIT, the accuracies of TB-SPRINT for the detection of rifampicin and isoniazid resistance ranged from 81 to 92% and 91.3 to 93.9%, respectively. Compared with MTBDRplus, the accuracies of TB-SPRINT for rifampicin and isoniazid were 99 and 94.2%, respectively. Moreover, the MC and ABC of TB-SPRINT were USD 127.78 and USD 109.94, respectively.

Conclusion

TB-SPRINT showed good results for isoniazid and rifampicin resistance detection, but still needs improvement to achieve In Vitro Diagnostics standards.

Frequency of the Mycobacterium tuberculosis RDRio genotype and its association with multidrug-resistant tuberculosis

BACKGROUND

In recent decades, Mycobacterium tuberculosis with the RD^Rio genotype, frequently isolated from tuberculosis patients in Rio de Janeiro, has become part of the Latin American - Mediterranean (LAM) family and has been associated with multidrug-resistant tuberculosis (MDR-TB). The aim of this study was to investigate the frequency of M. tuberculosis RD^Rio in the state of Minas Gerais, Brazil, and its relationship with MDR-TB.

METHODS

For convenience, 172 susceptible and 63 MDR M. tuberculosis isolates were taken from pulmonary samples from patients diagnosed between January 2007 and December 2011. The DNA extracted from these isolates was analyzed by spoligotyping, PCR-RFLP to characterize fbpC¹⁰³/Ag85C103, multiplex PCR to detect RD^Rio and RD174, and MIRU-VNTR 24 loci.

RESULTS

Among the 235 isolates, the RD^Rio pattern was identified in 122 (51.9%) isolates (IC 0.45-0.58), with 100 (42.5%) wild-type and 13 (5.5%) mixed pattern isolates, whereas RD174 was identified in 93 of the 122 RD^Rio positive samples (76.3%). The LAM family and the LAM9 lineage were the most frequently identified among the isolates in this study. Among the 63 MDR isolates, 41 (65.1%) were RD^Rio and 28 (44.4%) RD174.

CONCLUSION

The association of both deletions with MDR proved to be statistically significant, corroborating the few reports that have associated RD^Rio with MDR.

Comparative study of RFLP-IS6110 and MIRU-VNTR from Mycobacterium tuberculosis isolated in the state of Minas Gerais, Brazil

DNA genotyping of Mycobacterium tuberculosis has been widely applied in the understanding of disease transmission in many countries. The purpose of this study was to genotype the strains of M. tuberculosis isolated in patients with new tuberculosis (TB) cases in Minas Gerais, as well as to compare the similarity, discriminatory power, and agreement of the clusters between the IS6110 Restriction Fragment Length Polymorfism (RFLP) and 12 loci Variable Number Tandem Repeat – Mycobacterial Interspersed Repetitive Units (MIRU-VNTR) techniques. It was observed that 32% (66/204) of the isolated strains in the RFLP-IS6110 and 50.9% (104/204) of the isolated strains in the MIRU-VNTR presented a similarity of equal to or above 85%. The RFLP-IS6110 and MIRU-VNTR proved to contain a high discriminatory power. The similarity index resulting from the RFLP showed no recent transmission. Good agreement was observed between the techniques when clusters were detected; however, the best epidemiological relationship was found when using the RFLP-IS6110.

Correlation between the BACTEC MGIT 960 culture system with Genotype MTBDRplus and TB-SPRINT in multidrug resistant Mycobacterium tuberculosis clinical isolates from Brazil

BACKGROUND

The accurate detection of multidrug-resistant tuberculosis (MDR-TB) is critical for the application of appropriate patient treatment and prevention of transmission of drug-resistant Mycobacterium tuberculosis isolates. The goal of this study was to evaluate the correlation between phenotypic and molecular techniques for drug-resistant tuberculosis diagnostics. Molecular techniques used were the line probe assay genotype MTBDRplus and the recently described tuberculosis-spoligo-rifampin-isoniazid typing (TB-SPRINT) bead-based assay. Conventional drug susceptibility testing (DST) was done on a BACTECTM MGIT 960 TB.

METHOD

We studied 80 M. tuberculosis complex (MTC) clinical isolates from Minas Gerais state, of which conventional DST had classified 60 isolates as MDR and 20 as drug susceptible.

FINDINGS

Among the 60 MDR-TB isolates with MGIT as a reference, sensitivity, specificity, accuracy, and kappa for rifampicin (RIF) resistance using TB-SPRINT and MTBDRplus, were 96.7% versus 93.3%, 100.0% versus 100.0%, 97.5% versus 95.0% and 0.94 versus 0.88, respectively. Similarly, the sensitivity, specificity, accuracy, and kappa for isoniazid (INH) resistance were 85.0% and 83.3%, 100.0% and 100.0%, 88.8% and 87.5% and 0.74 and 0.71 for both tests, respectively. Finally, the sensitivity, specificity, accuracy, and kappa for MDR-TB were 85.0% and 83.3%, 100.0% and 100.0%, 88.8% and 87.5% and 0.74 and 0.71 for both tests, respectively.

MAIN CONCLUSIONS

Both methods exhibited a good correlation with the conventional DST. We suggest estimating the cost-effectiveness of MTBDRplus and TB-SPRINT in Brazil.

Prevalence of latent Mycobacterium tuberculosis infection in prisoners

Objective:

To determine the prevalence of and the factors associated with latent Mycobacterium tuberculosis infection (LTBI) in prisoners in the state of Minas Gerais, Brazil.

Methods:

This was a cross-sectional cohort study conducted in two prisons in Minas Gerais. Tuberculin skin tests were performed in the individuals who agreed to participate in the study.

Results:

A total of 1,120 individuals were selected for inclusion in this study. The prevalence of LTBI was 25.2%. In the multivariate analysis, LTBI was associated with self-reported contact with active tuberculosis patients within prisons (adjusted OR = 1.51; 95% CI: 1.05-2.18) and use of inhaled drugs (adjusted OR = 1.48; 95% CI: 1.03-2.13). Respiratory symptoms were identified in 131 (11.7%) of the participants. Serological testing for HIV was performed in 940 (83.9%) of the participants, and the result was positive in 5 (0.5%). Two cases of active tuberculosis were identified during the study period.

Conclusions:

Within the prisons under study, the prevalence of LTBI was high. In addition, LTBI was associated with self-reported contact with active tuberculosis patients and with the use of inhaled drugs. Our findings demonstrate that it is necessary to improve the conditions in prisons, as well as to introduce strategies, such as chest X-ray screening, in order to detect tuberculosis cases and, consequently, reduce M. tuberculosis infection within the prison system.

Genetic diversity and molecular epidemiology of multidrug-resistant Mycobacterium tuberculosis in Minas Gerais State, Brazil

Background

We aimed to characterize the genetic diversity of drug-resistant Mycobacterium tuberculosis (MTb) clinical isolates and investigate the molecular epidemiology of multidrug-resistant (MDR) tuberculosis from Minas Gerais State, Brazil.

Methods

One hundred and four MTb clinical isolates were assessed by IS6110-RFLP, 24-locus mycobacterial interspersed repetitive units variable-number tandem repeats (MIRU-VNTR), TB-SPRINT (simultaneous spoligotyping and rifampicin-isoniazid drug-resistance mutation analysis) and 3R-SNP-typing (analysis of single-nucleotide polymorphisms in the genes involved in replication, recombination and repair functions).

Results

Fifty-seven different IS6110-RFLP patterns were found, among which 50 had unique patterns and 17 were grouped into seven clusters. The discriminatory index (Hunter and Gaston, HGDI) for RFLP was 0.9937. Ninety-nine different MIRU-VNTR patterns were found, 95 of which had unique patterns and nine isolates were grouped into four clusters. The major allelic diversity index in the MIRU-VNTR loci ranged from 0.6568 to 0.7789. The global HGDI for MIRU-VNTR was 0.9991. Thirty-two different spoligotyping profiles were found: 16 unique patterns (n = 16) and 16 clustered profiles (n = 88). The HGDI for spoligotyping was 0.9009. The spoligotyped clinical isolates were phylogenetically classified into Latin-American Mediterranean (66.34 %), T (14.42 %), Haarlem (5.76 %), X (1.92 %), S (1.92 %) and U (unknown profile; 8.65 %). Among the U isolates, 77.8 % were classified further by 3R-SNP-typing as 44.5 % Haarlem and 33.3 % LAM, while the 22.2 % remaining were not classified. Among the 104 clinical isolates, 86 were identified by TB-SPRINT as MDR, 12 were resistant to rifampicin only, one was resistant to isoniazid only, three were susceptible to both drugs, and two were not successfully amplified by PCR. A total of 42, 28 and eight isolates had mutations in rpoB positions 531, 526 and 516, respectively. Correlating the cluster analysis with the patient data did not suggest recent transmission of MDR-TB.

Conclusions

Although our results do not suggest strong transmission of MDR-TB in Minas Gerais (using a classical 100 % MDR-TB identical isolates cluster definition), use of a smoother cluster definition (>85 % similarity) does not allow us to fully eliminate this possibility; hence, around 20–30 % of the isolates we analyzed might be MDR-TB transmission cases.

In-house PCR with DNA extracted directly from positive slides to confirm or exclude the diagnosis of tuberculosis: focus on biosafety

The possibility to obtain DNA from smears is a valuable alternative to remedy the lack of samples when they are totally used for bacilloscopy; this technique solves the biosafety problem related to a possible accident with the transportation of flasks containing potentially transmissible clinical samples. Hence, the purpose of this study was to utilize the insertion sequence IS6110 for amplification of DNA from a smear-positive sample for tuberculosis (TB) diagnosis. Among the 52 positive bacilloscopies, sensitivity, specificity, positive predictive value and negative predictive value were 52.3%, 100%, 100% and 89.7%, respectively whereas accuracy was 90.7%. The IS6110-based PCR for TB diagnosis developed in DNA extracted from a positive smear is a fast, simple, specific, and safe method.