Primary drug resistance among pulmonary treatment-naïve tuberculosis patients in Amazonas State, Brazil

Prevalence of Rifampicin resistance tuberculosis among presumptive tuberculosis patients in Egypt-2021: a national health facility-based survey

BACKGROUND

The magnitude of MDR-TB cases was noticeable in Egypt. However, the last national survey was 11-years ago. The current survey was conducted to determine the prevalence of rifampicin resistance among sputum smear-positive pulmonary tuberculosis patients in Egypt.

METHODS

A national health facility-based cross-sectional study was conducted in 14 randomly selected governorates in Egypt between August 2020 and September 2021. All presumptive TB cases, either new or previously treated according to WHO definitions, with no gender, age, or nationality limitations, and provided informed consent were included in the study. Each patient completed a case report form (CRF). The CRF included socio-demographic and clinical data. Sputum samples were collected according to standard techniques and cultured on Lowenstein-Jensen (L-J) medium. Gene X-pert test was carried out first on the samples for simultaneous identification of MTB and rifampicin resistance. The prevalence of RR was calculated using crude, cluster, and weighted methods. Factors associated with RR were analyzed by bivariate and multivariate techniques.

RESULTS

Among the total 849 presumptive TB patients enrolled in the study, 710 (83.6%) patients were subjected to Gene X-pert testing (MTB/RIF). The crude prevalence of RR was 3.32% (95% CI: 1.89-4.76%) among the new cases and 9.46% (95% CI: 2.63-16.29%) among the retreated cases with an overall estimate of 3.99%; (95% CI: 2.51-5.47%). By cluster analysis the overall prevalence of RR was 5.01% (95% CI: 2.90-7.13). Factors associated with the prevalence of RR were co-morbidity with bronchial asthma, drug abuse and history of contact with a family member with TB.

CONCLUSION

The prevalence of RR among either new or retreated cases TB patients was lower than the previous Egyptian rates in 2010-2012. The strongest predictor associated with RR was comorbidity with bronchial asthma.

Differential yield of universal versus selective drug susceptibility testing of patients with tuberculosis in high-burden countries: a systematic review and meta-analysis

Introduction

Although universal drug susceptibility testing (DST) is a component of the End-TB Strategy, over 70% of drug-resistant tuberculosis (DR-TB) cases globally remain undetected. This detection gap reflects difficulties in DST scale-up and substantial heterogeneity in policies and implemented practices. We conducted a systematic review and meta-analysis to assess whether implementation of universal DST yields increased DR-TB detection compared with only selectively testing high-risk groups.

Methods

PubMed, Embase, Global Health, Cochrane Library and Web of Science Core Collection were searched for publications reporting on the differential yield of universal versus selective DST implementation on the proportion of DR-TB, from January 2007 to June 2019. Random-effects meta-analyses were used to calculate respective pooled proportions of DR-TB cases detected; Higgins test and prediction intervals were used to assess between-study heterogeneity. We adapted an existing risk-of-bias assessment tool for prevalence studies.

Results

Of 18 736 unique citations, 101 studies were included in the qualitative synthesis. All studies used WHO-endorsed DST methods, and most (87.1%) involved both high-risk groups and the general population. We found only cross-sectional, observational, non-randomised studies that compared universal with selective DST strategies. Only four studies directly compared the testing approaches in the same study population, with the proportion of DR-TB cases detected ranging from 2.2% (95% CI: 1.4% to 3.2%) to 12.8% (95% CI: 11.4% to 14.3%) with selective testing, versus 4.4% (95% CI: 3.3% to 5.8%) to 9.8% (95% CI: 8.9% to 10.7%) with universal testing. Broad population studies were very heterogeneous. The vast majority (88/101; 87.1%) reported on the results of universal testing. However, while 37 (36.6%)/101 included all presumptive TB cases, an equal number of studies applied sputum-smear as a preselection criterion. A meaningful meta-analysis was not possible.

Conclusion

Given the absence of randomised studies and the paucity of studies comparing strategies head to head, and selection bias in many studies that applied universal testing, our findings have limited generalisability. The lack of evidence reinforces the need for better data to inform policies.

Primary and acquired multidrug-resistant tuberculosis: Predictive factors for unfavorable treatment outcomes in Rio de Janeiro, 2000-2016

Objective

To identify clinical and demographic factors associated with unfavorable treatment outcomes in patients with primary and acquired multidrug-resistant tuberculosis (MDR-TB) in Rio de Janeiro State.

Methods

Retrospective cohort study using data on 2 269 MDR-TB cases in 2000–2016. Factors associated with unsuccessful, loss to follow-up, and death outcomes in patients with primary and acquired resistance were investigated with bivariate and multivariate regression.

Results

Primary resistance was 14.7% among MDR-TB cases. The unfavorable outcomes proportion was 30.3% in the primary resistance group and 46.7% in the acquired resistance group. There were significant differences in demographic and clinical characteristics between the two groups. Proportionally, the group with primary resistance had more cases among women (46.4% vs. 33.5% in the acquired resistance group), Caucasians (47.3% and 34%), and those with ≥8 years of schooling (37.7% and 27.4%). Extensively drug-resistant TB patients had 12.2-fold higher odds of unsuccessful outcome than MDR-TB patients, and comorbidities had 2-fold higher odds in the primary resistance group. Extensively drug-resistant TB had 5.43-fold higher odds in the acquired MDR-TB group. Bilateral disease and <8 years of schooling were associated with unsuccessful outcome in both groups. Being an inmate had 8-fold higher odds of loss to follow-up in the primary resistance group. Culture conversion by the sixth month was a protective factor for all outcomes.

Conclusions

Primary resistance cases of MDR-TB constitute a different transmission reservoir, which is related to other chronic diseases associated with higher acquisition of TB. The poor results observed in Rio de Janeiro State can contribute to increasing the transmission of primary MDR-TB, thus favoring drug resistance.

Prevalence of multidrug-resistant tuberculosis in Latin America and the Caribbean: a systematic review and meta-analysis

OBJECTIVES

To evaluate the prevalence of multidrug-resistant tuberculosis (MDR-TB) in individuals living in Latin America and the Caribbean (LAC).

METHODS

We searched the MEDLINE, Embase and Literatura Latino Americana e do Caribe em Ciências da Saúde (Lilacs) databases until 08 August 2019 for all studies on the subject, without time or language restrictions. Original studies reporting the prevalence of infection with Mycobacterium tuberculosis resistant to isoniazid and rifampicin simultaneously (MDR) in LAC, the prevalence of resistance in cases with no previous treatment (new cases) and the prevalence of resistance in previously treated cases were selected. Considering the expected heterogeneity between studies, all analyses were performed using the random effects model, and heterogeneity was assessed using the I² statistic.

RESULTS

We included 91 studies from 16 countries. The estimated overall prevalence was 13.0% (95% CI 12.0-14.0%), and the heterogeneity between studies was substantial (I²  = 96.1%). In the subgroup analyses, it was observed that the prevalence of MDR-TB among new cases was 7.0% (95% CI 6.0-7.0%) and in previously treated cases was 26.0% (95% CI 24.0-28.0%).

CONCLUSIONS

This review highlights multidrug resistance to antituberculosis drugs in LAC, indicating that prevention strategies have not been effective. Government institutions should invest heavily in strategies for early diagnosis and the rapid availability of effective treatments and prioritise adequate protection for health professionals. In addition, screening programmes should be adopted to prevent secondary cases.

Molecular characterization of pre-extensive drug resistant Mycobacterium tuberculosis in Northeast Brazil

In Fortaleza, the capital of Ceara State, Brazil, the detection rate of tuberculosis (TB) in 2018 was 65.5/100,000 inhabitants with a cure rate of 59.1%, which is higher than the country average. This study investigated the risk factors associated with drug-resistant tuberculosis (DR-TB) and identified the drug-resistance phenotype and resistance-conferring mutations. The geographic distribution of DR-TB in Fortaleza, Brazil, was also determined. From March 2017 to February 2018, 41 DR-TB isolates and 69 drug-susceptible pulmonary TB isolates were obtained from patients seen at a referral hospital in Fortaleza, Brazil. Samples were subjected to phenotypic and genetic analysis of resistance; the spatial distribution of the participants was also analyzed. Primary resistance was high (50.9%) among participants. The following risk factors for DR were identified: being female ( p = 0.03), having diabetes ( p < 0.01), history of previous TB disease ( p < 0.01), and the number of intra-domiciliary contacts ( p < 0.01). Analysis by multiplex allele-specific polymerase chain reaction detected mutations in the genes katG (65.8%) , rpoB (43.9%), inhA promoter (14.6%), and gyrA (9.8%). Sequencing identified mutations in the the genes katG (75.6%), inhA promoter (19.5%), rpoB (85.4%), and gyrA (100%). There was no mutation in the rrs gene. Spatial analysis showed DR-TB isolates distributed in areas of low socioeconomic status in the city of Fortaleza. Our results emphasized the importance of detecting resistance to TB drugs. The resistance found in the gene gyrA is of concern due to the high number of pre-extensive DR-TB cases in Fortaleza.

Primary bacillary resistance in multidrug-resistant tuberculosis and predictive factors associated with cure at a referral center in São Paulo, Brazil

Objective:

To identify transmitted or primary resistance among cases of multidrug-resistant tuberculosis and predictive factors for cure in multidrug-resistant tuberculosis after the first treatment.

Method:

Descriptive study of a cohort from 2006 to 2010, in a reference unit of tuberculosis in São Paulo, Brazil. The data were obtained by the revision of medical records. Clinical criteria were used to classify transmitted and acquired resistance. Extended primary resistance was also defined, in this study, as cases initially treated with a standardized scheme, but with no therapeutic success, and the pre-treatment drug susceptibility test (DST) showed presence of resistance.

Results:

156 patients with multidrug-resistant tuberculosis and their respective sputum samples were eligible for the study. Only 7% of the patients were positive for the human immunodeficiency virus (HIV). Previous treatment occurred in 95% of the sample. The cure rate after the first treatment was 54%. The median bacteriological conversion time of those who healed was one month. Bacillary resistance was considered acquired resistance in 100 (64%) and transmitted resistance in 56 (36%). By logistic regression, patients who presented primary multidrug-resistant tuberculosis (odds ratio-OR = 6,29), without comorbidity (OR = 3,37) and with higher initial weight (OR = 1.04) were associated with cure after the first treatment.

Conclusion:

The early detection of bacillary resistance and appropriate treatment are in favor of healing. Thus, it is crucial to know exactly the primary resistance rate avoiding the use of inadequate treatments, amplification of bacillary resistance and its transmission.

[Antituberculosis-drug resistance in the border of Brazil with Paraguay and Bolivia]

Objetivo.

Estimar as taxas de resistência às drogas entre casos de tuberculose pulmonar (TBP) para o estado de Mato Grosso do Sul, Brasil, e especificamente para a região da fronteira com Paraguai e Bolívia, além de identificar fatores de risco associados.

Métodos.

O presente estudo epidemiológico, transversal, enfocou os casos de TBP registrados de janeiro de 2007 a dezembro de 2010 no Sistema de Informação de Agravos de Notificação da Secretaria de Estado de Saúde com resultados do teste de suscetibilidade a rifampicina, isoniazida, etambutol e estreptomicina. Definiram-se como variáveis dependentes o desenvolvimento de resistência a uma única droga e a qualquer combinação de drogas. As variáveis independentes foram ser caso novo ou tratado, residência em região de fronteira ou outra região, presença ou ausência de diabetes e história de alcoolismo.

Resultados.

Foram identificados 789 casos de TBP com teste de suscetibilidade. As características associadas à resistência foram: caso tratado (P=0,0001), região de fronteira (P=0,0142), alcoolismo (P=0,0451) e diabetes (P=0,0708). As taxas de resistência combinada, primária e adquirida no estado foram de 16,3%, 10,6% e 39,0%, e na fronteira, de 22,3%, 19,2% e 37,5%. As taxas de resistência a múltiplas drogas combinada, primária e adquirida no estado foram de 1,8%, 0,6% e 6,3%, e na fronteira, de 3,1%, 1,2% e 12,5%.

Conclusões.

O estado deve, na região de fronteira, realizar cultura em todos os sintomáticos respiratórios, investigar o padrão de resistência nos casos confirmados, adotar o tratamento diretamente observado nos casos de TBP e desencadear ações de saúde conjuntas com os países fronteiriços. Em todo o estado, é necessário monitorar os níveis de resistência adquirida, ampliar a investigação de resistência para todos os casos tratados e adotar o tratamento diretamente observado prioritariamente entre pacientes com alcoolismo e diabetes.

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.