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

BACKGROUND: In recent decades, Mycobacterium tuberculosis with the RDRio 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 RDRio 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 RDRio and RD174, and MIRU-VNTR 24 loci. RESULTS: Among the 235 isolates, the RDRio 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 RDRio 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 RDRio 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 RDRio with MDR.

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.

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.

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).

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.

RDRio Mycobacterium tuberculosis infection is associated with a higher frequency of cavitary pulmonary disease.

Molecular genotyping has shown Mycobacterium tuberculosis lineages to be geographically restricted and associated with distinct ethnic populations. Whether tuberculosis (TB) caused by some M. tuberculosis lineages can present with a differential clinical spectrum is controversial because of very limited clinical data. We recently reported on the discovery of RD(Rio) M. tuberculosis, a Latin American-Mediterranean sublineage that is the predominant cause of TB in Rio de Janeiro, Brazil. To investigate the clinical attributes of TB caused by RD(Rio) strains, we studied a cohort of TB cases from Belo Horizonte, Brazil, in which clinical information recorded on a standardized questionnaire was collected at the time of microbiological testing. These patients were referred for culture and drug susceptibility testing because of the clinical suspicion of "complicated" TB, as demonstrated by high rates of multidrug resistance (12%) and cavitary TB (80%). We performed spoligotyping and RD(Rio) genotyping on the M. tuberculosis strains and analyzed the clinical data from these patients. RD(Rio) M. tuberculosis accounted for 37% of the total TB burden. Multivariate analysis found a significant association between TB caused by RD(Rio) strains and pulmonary cavitation and residence in Belo Horizonte. Since cavitary TB is associated with higher sputum bacillary load, our findings support the hypothesis that RD(Rio) M. tuberculosis is associated with a more "severe" disease as a strategy to increase transmission. Future studies are needed to confirm these observations and to better define the contribution of RD(Rio) M. tuberculosis to the global TB epidemic.

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.

Nontuberculous mycobacteria in patients of a specialty hospital

ABSTRACT 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.

Characteristics of tuberculosis in the state of Minas Gerais, Brazil: 2002-2009.

OBJECTIVE: To analyze the profile of tuberculosis cases reported between 2002 and 2009 in the state of Minas Gerais, Brazil, according to sociodemographic, clinical, and laboratory characteristics, as well as to comorbidities and mortality. METHODS: This was a descriptive, epidemiological study based on data obtained from the Brazilian Case Registry Database and the Brazilian Mortality Database for the 2002-2009 period. RESULTS: There were 47,285 reported cases of tuberculosis, corresponding to a mean incidence of 22.3/100,000 population. The individuals diagnosed with tuberculosis were predominantly in the 20- to 49-year age bracket and male (62.4% and 67.0%, respectively). Individuals with a low level of education accounted for 18.5% of the cases. New cases, cases of recurrence, and cases of retreatment accounted for 83.7%, 5.7%, 5.7%, respectively. The rates of cure and treatment noncompliance were 66.2% and 11.2%, respectively; multidrug-resistant tuberculosis was identified in 0.2% of the cases; and the mortality rate was 12.9%. The directly observed treatment, short-course (DOTS) strategy was applied in 21.8% of the cases. Sputum smear microscopy and culture were performed in only 73.9% and 12.9% of the cases, respectively. Chest X-rays were performed in 90.5% of the cases. Pulmonary tuberculosis was the predominant form (in 83.9%). Comorbidity with alcoholism, HIV infection, and diabetes mellitus were identified in 17.2%, 8.3%, and 3.8%, respectively. CONCLUSIONS: During the study period, the numbers of new cases, cases of treatment noncompliance, and deaths were high, comorbidities were common, and there was a failure to perform adequately basic tests for the diagnosis of tuberculosis. Multidisciplinary approaches, expanded use of the DOTS strategy, better knowledge of the distribution of tuberculosis, and improvements in the databases are needed in order to achieve better control of the disease in the state of Minas Gerais.

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

Abstract 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.

Characteristics of tuberculosis in the state of Minas Gerais, Brazil: 2002-2009 / Características da tuberculose no estado de Minas Gerais entre 2002 e 2009

OBJECTIVE: To analyze the profile of tuberculosis cases reported between 2002 and 2009 in the state of Minas Gerais, Brazil, according to sociodemographic, clinical, and laboratory characteristics, as well as to comorbidities and mortality. METHODS: This was a descriptive, epidemiological study based on data obtained from the Brazilian Case Registry Database and the Brazilian Mortality Database for the 2002-2009 period. RESULTS: There were 47,285 reported cases of tuberculosis, corresponding to a mean incidence of 22.3/100,000 population. The individuals diagnosed with tuberculosis were predominantly in the 20- to 49-year age bracket and male (62.4% and 67.0%, respectively). Individuals with a low level of education accounted for 18.5% of the cases. New cases, cases of recurrence, and cases of retreatment accounted for 83.7%, 5.7%, 5.7%, respectively. The rates of cure and treatment noncompliance were 66.2% and 11.2%, respectively; multidrug-resistant tuberculosis was identified in 0.2% of the cases; and the mortality rate was 12.9%. The directly observed treatment, short-course (DOTS) strategy was applied in 21.8% of the cases. Sputum smear microscopy and culture were performed in only 73.9% and 12.9% of the cases, respectively. Chest X-rays were performed in 90.5% of the cases. Pulmonary tuberculosis was the predominant form (in 83.9%). Comorbidity with alcoholism, HIV infection, and diabetes mellitus were identified in 17.2%, 8.3%, and 3.8%, respectively. CONCLUSIONS: During the study period, the numbers of new cases, cases of treatment noncompliance, and deaths were high, comorbidities were common, and there was a failure to perform adequately basic tests for the diagnosis of tuberculosis. Multidisciplinary approaches, expanded use of the DOTS strategy, better knowledge of the distribution of tuberculosis, and improvements in the databases are needed ...

OBJETIVO: Analisar o perfil de casos de tuberculose no estado de Minas Gerais entre 2002 e 2009, segundo características sociodemográficas, clínicas e laboratoriais, assim como presença de comorbidades e mortalidade. MÉTODOS: Estudo epidemiológico descritivo com levantamento de dados dos casos notificados no Sistema de Informação de Agravos de Notificação e Sistema de Informação de Mortalidade entre 2002 e 2009. RESULTADOS: Foram notificados 47.285 casos de tuberculose nos anos estudados, com média de incidência 22,3/100.000 habitantes. Os indivíduos com tuberculose eram predominantemente da faixa etária de 20-49 anos (62,4%), do sexo masculino (67,0%) e tinham baixa escolaridade (18,5%). Casos novos, de recidiva e de retratamento representaram, respectivamente, 83,7%, 5,7% e 5,7% do total de casos. As proporções de cura, abandono do tratamento e tuberculose multirresistente foram, respectivamente, 73,1%, 11,2% e 0,2%, enquanto o coeficiente de mortalidade foi 12,9%. O tratamento diretamente observado (TDO) foi administrado em 21,8% dos casos. A baciloscopia e a cultura de escarro somente foram realizadas em 73.9% e 12,9% dos casos, respectivamente. A radiografia de tórax foi realizada em 90,5% dos casos. A forma pulmonar prevaleceu (83,9%). A comorbidade com alcoolismo, infecção pelo HIV e diabetes mellitus foi identificada em 17,2%, 8,3% e 3,8% dos casos, respectivamente. CONCLUSÕES: No período estudado, o número de casos novos, de abandono e de óbitos foi elevado, as comorbidades foram relevantes, e os exames básicos não foram realizados adequadamente para o diagnóstico da tuberculose. São necessários o trabalho multiprofissional, ampliação da estratégia TDO, maior conhecimento da distribuição ...