A major subgroup of Beijing family Mycobacterium tuberculosis is associated with multidrug resistance and increased transmissibility

Mycobacterium tuberculosis lineage 4 associated with cavitations and treatment failure

BACKGROUND

Mycobacterium tuberculosis genotyping has been crucial to determining the distribution and impact of different families on disease clinical presentation. The aim of the study was to evaluate the associations among sociodemographic and clinical characteristics and M. tuberculosis lineages from patients with pulmonary tuberculosis in Orizaba, Veracruz, Mexico.

METHODS

We analyzed data from 755 patients whose isolates were typified by 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR). The associations among patient characteristics and sublineages found were evaluated using logistic regression analysis.

RESULTS

Among M. tuberculosis isolates, 730/755 (96.6%) were assigned to eight sublineages of lineage 4 (Euro-American). Alcohol consumption (adjusted odds ratio [aOR] 1.528, 95% confidence interval (CI) 1.041-2.243; p = 0.030), diabetes mellitus type 2 (aOR 1.625, 95% CI 1.130-2.337; p = 0.009), sputum smear positivity grade (3+) (aOR 2.198, 95% CI 1.524-3.168; p < 0.001) and LAM sublineage isolates (aOR 1.023, 95% CI 1.023-2.333; p = 0.039) were associated with the presence of cavitations. Resistance to at least one drug (aOR 25.763, 95% CI 7.096-93.543; p < 0.001) and having isolates other than Haarlem and LAM sublineages (aOR 6.740, 95% CI 1.704-26.661; p = 0.007) were associated with treatment failure. In a second model, multidrug resistance was associated with treatment failure (aOR 31.497, 95% CI 5.119-193.815; p < 0.001). Having more than 6 years of formal education was not associated with treatment failure.

CONCLUSIONS

Knowing M. tuberculosis genetic diversity plays an essential role in disease development and outcomes, and could have important implications for guiding treatment and improving tuberculosis control.

Comparison on Major Gene Mutations Related to Rifampicin and Isoniazid Resistance between Beijing and Non-Beijing Strains of Mycobacterium tuberculosis: A Systematic Review and Bayesian Meta-Analysis

Objective: The Beijing strain of Mycobacterium tuberculosis (MTB) is controversially presented as the predominant genotype and is more drug resistant to rifampicin and isoniazid compared to the non-Beijing strain. We aimed to compare the major gene mutations related to rifampicin and isoniazid drug resistance between Beijing and non-Beijing genotypes, and to extract the best evidence using the evidence-based methods for improving the service of TB control programs based on genetics of MTB. Method: Literature was searched in Google Scholar, PubMed and CNKI Database. Data analysis was conducted in R software. The conventional and Bayesian random-effects models were employed for meta-analysis, combining the examinations of publication bias and sensitivity. Results: Of the 8785 strains in the pooled studies, 5225 were identified as Beijing strains and 3560 as non-Beijing strains. The maximum and minimum strain sizes were 876 and 55, respectively. The mutations prevalence of rpoB, katG, inhA and oxyR-ahpC in Beijing strains was 52.40% (2738/5225), 57.88% (2781/4805), 12.75% (454/3562) and 6.26% (108/1724), respectively, and that in non-Beijing strains was 26.12% (930/3560), 28.65% (834/2911), 10.67% (157/1472) and 7.21% (33/458), separately. The pooled posterior value of OR for the mutations of rpoB was 2.72 ((95% confidence interval (CI): 1.90, 3.94) times higher in Beijing than in non-Beijing strains. That value for katG was 3.22 (95% CI: 2.12, 4.90) times. The estimate for inhA was 1.41 (95% CI: 0.97, 2.08) times higher in the non-Beijing than in Beijing strains. That for oxyR-ahpC was 1.46 (95% CI: 0.87, 2.48) times. The principal patterns of the variants for the mutations of the four genes were rpoB S531L, katG S315T, inhA-15C > T and oxyR-ahpC intergenic region. Conclusion: The mutations in rpoB and katG genes in Beijing are significantly more common than that in non-Beijing strains of MTB. We do not have sufficient evidence to support that the prevalence of mutations of inhA and oxyR-ahpC is higher in non-Beijing than in Beijing strains, which provides a reference basis for clinical medication selection.

Role of ESAT-6 in pathogenicity of Beijing and non-Beijing Mycobacterium tuberculosis isolates

BACKGROUND

Mycobacterium tuberculosis Beijing genotype was associated with tuberculosis outbreaks and increased transmissibility. To understand the variation in virulence between Beijing and non-Beijing clinical isolates of M.tuberculosis genotypes, the esat-6 gene sequencing, and its expression was compared in the macrophage environment.

MATERIALS & METHODS

Among 64 nonrepetitive, culture-positive M.tuberculosis, DNA extraction of 24 and 40 pure confirmed Beijing and non-Beijing isolates was accompanied by the boiling method. esat-6 gene PCR amplification and their sequencing were carried out by specific primers and its expression was performed on human macrophage cell line U937 after 6, 12, and 18 h of exposure to bacilli. The esat-6 mRNA transcription and expression in M. tuberculosis treated macrophage by Real-Time PCR and Western blot method.

RESULTS

Data analysis based on sequencing of the east-6 gene PCR product showed that this gene exists in all isolates and there are no changes or single nucleotide variation between the Beijing and non-Beijing isolates. In Beijing strains, the esat-6 expression was increased during the study times, but it was constant in non-Beijing isolates. esat-6 gene expression in Beijing isolates reached to about 44.9 times more than non-Beijing isolates after 18 h incubation on the macrophages cell line.

CONCLUSION

esat-6 is a conserved gene both in Beijing and non-Beijing isolates of M.tuberculosis. More expression of the east-6 gene in the macrophage model may indicate that this gene is likely to play a more important role in increasing the pathogenicity of Beijing strains.

Genotypes of Mycobacterium tuberculosis isolates circulating in Shaanxi Province, China

Objectives

The prevalence of drug-resistant TB in Shaanxi Province is higher than other areas. This study was aimed to investigate the genetic diversity and epidemiology of Mycobacterium tuberculosis clinical strains in Shaanxi Province, China.

Methods

From January to December 2016, a total of 298 Mycobacterium tuberculosis clinical isolates from smear-positive pulmonary tuberculosis patients were genotyped by Mcspoligotyping and 15-locus VNTR.

Results

We found that the Beijing family strains was the most prominent family(81.54%, 243/298). Other family strains included T family(9.06%, 27/298), U family(0.67%, 2/298), LAM9 family(0.34%, 1/298) and Manu family(0.34%, 1/298). The rates of multidrug-resistant (MDR) M.Tuberculosis, age, type of case and education between Beijing and non-Beijing family strains were not statistically different, while the distribution in the three different regions among these was statistically significant.

VNTR results showed that strains were classified into 280 genotypes, and 33 (11.07%) strains could be grouped into 14 clusters. 11 of the 15-VNTR loci were highly or moderately discriminative according to the Hunter-Gaston discriminatory index.

Conclusions

We concluded that the Beijing family genotype was the most prevalent genotype and 15-locus VNTR typing might be suitable for genotyping of M. tuberculosis in Shaanxi Province. There was less association between Beijing family genotypes and drug resistance in our study area.

Review on emergence of drug-resistant tuberculosis (MDR & XDR-TB) and its molecular diagnosis in Ethiopia

Tuberculosis (TB) remains a major global health problem and ranks as the second leading cause of death among deaths caused by infectious diseases worldwide. Although the availability of short-course regimens as first-line anti-tuberculosis drugs, the emergence of drug-resistant Mycobacterium tuberculosis strains pose a major challenge to the prevention and control efforts of national tuberculosis programs (NTPs). M. tuberculosis changes its cellular environment with the mechanisms that have been evolved since prehistoric times. The interactions between the bacteria and the host environment have been studied well. However, the studies at molecular level began to emerge recently including expression profiling of micro RNA (miRNA) and literature survey revealed that researchers find more information about their regulatory role in biological processes including immune response to infectious agents like mycobacteria. In developing countries, including Ethiopia, the burden of tuberculosis and or drug resistance profile of M. tuberculosis remains largely unexplored, mainly due to lack of quality controlled second-line laboratory tests and also lack of knowledge on molecular diagnostics. This review describes the disease etiology, pathogenesis, epidemiology, molecular mechanism and advanced molecular diagnostics for precision MDR-TB diagnosis.

Bi-logistic model for disease dynamics caused by Mycobacterium tuberculosis in Russia

In this work, we explore epidemiological dynamics by the example of tuberculosis in Russian Federation. It has been shown that the epidemiological dynamics correlates linearly with the virulence of Mycobacterium tuberculosis during the period 1987-2012. To construct an appropriate model, we have analysed (using LogLet decomposition method) epidemiological World Health Organization (WHO) data (period 1980-2014) and obtained, as result of their integration, a curve approximated by a bi-logistic function. This fact allows a subdivision of the whole population into parts, each of them satisfies the Verhulst-like models with different constant virulences introduced into each subsystem separately. Such a subdivision could be interconnected with the heterogeneous structure of mycobacterial population that has a high ability of adaptation to the host and strong mutability.

Spoligotype defined lineages of Mycobacterium tuberculosis and drug resistance: Merely a casual correlation?

Drug-resistant tuberculosis (TB) is a major challenge to TB control strategy worldwide. Analysis of genetic polymorphism among drug resistant Mycobacterium tuberculosis (MTB) strains may help provide some insight into the transmission dynamics of these strains. Spoligotyping is a widely used technique to identify genetic polymorphism, based on 43 known spacers interspersed between direct repeat regions. Considerable work has been done in various parts of the world using this technique to identify and analyse the polymorphic nature of MTB. Many studies have been carried out to determine the association of drug resistance with spoligotype defined lineages, and much data has been produced over the years. New information continues to be generated. This review aims to put together the findings of relevant studies in an attempt to understand the correlation of drug resistance with spoligotype defined lineages of MTB. This would help provide a perspective of the available data that can be used as a starting point to understand the molecular epidemiology of drug resistant TB.

Molecular Typing Characteristic and Drug Susceptibility Analysis of Mycobacterium tuberculosis Isolates from Zigong, China

China is one of the 22 countries with high TB burden worldwide, and Sichuan contained the second-largest number of TB cases among all of the Chinese provinces. But the characteristics of Mycobacterium tuberculosis circulated in Zigong, Sichuan, were still unknown. To investigate the character and drug resistance profile, 265 clinical isolates were cultured from tuberculosis patient's sputum samples in the year of 2010, of which the genetic profile was determined by using Spoligotyping and MIRU-VNTR typing methods, and the drug sensibility testing to the four first-line and four second-line antituberculosis (anti-TB) drugs was performed by using proportion method on Lowenstein-Jensen (L-J) media. The major Spoligotype was Beijing family (143/265, 53.96%), followed by T (80/265, 30.19%) and H (9/265, 3.40%) genotypes; the total Hunter-Gaston discrimination index (HGDI) of the 24 loci MIRU-VNTR was 0.9995. About 27.17% (72/265) of the isolates were resistant to at least one of the eight tested anti-TB drugs, and for Beijing and non-Beijing family isolates the proportion of drug resistance was 28.47% (41/144) and 25.62% (31/121), respectively. That is, the most prevalent genotype here was Beijing family, and the 24 loci VNTR analysis could supply a high resolution for genotyping, and Beijing and non-Beijing isolates had no difference (p > 0.05) for drug resistance.

Drug resistance characteristics and cluster analysis of M. tuberculosis in Chinese patients with multiple episodes of anti-tuberculosis treatment

Background

Tuberculosis (TB) patients with multiple episodes of anti-TB treatment represent an important source of TB transmission, as well as a serious threat to the control of drug resistant TB, due to the high risk of multidrug and extensively drug resistance (MDR/XDR) and elongating infectiousness of this patient group. In this study we analyzed the possible risk of development and transmission of MDR and XDR in TB patients with multiple episodes of previous treatment history.

Methods

The study subjects were pulmonary TB patients who had at least two episodes of previous anti-TB treatment. A total of 166 eligible patients were identified from 10 counties/districts distributed in east, west, north, south and central China. Drug susceptibility test (DST) was performed by proportion method on LJ-media for the 1st line anti-TB drugs and a line probe assay was used to detect mutations related to resistance of the key 2nd-line drugs. Genotyping of M. tuberculosis (Mtb) was performed with MIRU-VNTR and Spoligotyping.

Results

Resistances to 1st-line drugs was observed in 122 (73.5 %) of the 166 Mtb isolates with 97 (58.4 %) being MDR-TB. Mutations relevant to 2nd-line drug resistance was seen in 63 isolates, including 35 MDR-TB isolates (30 pre-XDR, 5 XDR-TB). The Spoligotyping revealed 83.1 % Mtb isolates belonged to the Beijing family. The MIRU-VNTR based genotyping revealed 32 (19.3 %) of patients were infected with more than one strain. The number of previous TB treatment episode was found being significantly associated with the risk of MDR-TB and XDR-TB. Among the remaining 134 patients infected with a single Mtb strain, MIRU-VNTR revealed a high homogeneity of strain especially within Beijing family despite the polymorphic variations along with geographic locations.

Conclusions

The high genetic relatedness and risk of MDR-TB and subsequent pre-XDR and XDR-TB among repeatedly treated patients suggest the establishment of M/XDR Mtb in this specific patient population. It highlights the urgent needs of providing DST of both 1st- and 2nd-line drugs before and during the medication in China’s MDR-TB control program. Furthermore, the possibility of infection with multiple strains should also be considered to be associated with the drug resistance, which calls for the modification of treatment regimen.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1331-z) contains supplementary material, which is available to authorized users.

Temporal dynamics of Mycobacterium tuberculosis genotypes in New South Wales, Australia

BACKGROUND

Molecular epidemiology of Mycobacterium tuberculosis, its transmission dynamics and population structure have become important determinants of targeted tuberculosis control programs. Here we describe recent changes in the distribution of M. tuberculosis genotypes in New South Wales (NSW), Australia and compared strain types with drug resistance, site of disease and demographic data.

METHODS

We evaluated all culture-confirmed newly identified tuberculosis cases in NSW, Australia, from 2010-2012. M. tuberculosis population structure and clustering rates were assessed using 24-loci Mycobacterial interspersed repetitive unit (MIRU) analysis and compared to MIRU data from 2006-2008.

RESULTS

Of 1177 tuberculosis cases, 1128 (95.8%) were successfully typed. Beijing and East African Indian (EAI) lineage strains were most common (27.6% and 28.5%, respectively) with EAI strains increasing in relative abundance from 11.8% in 2006-2008 to 28.5% in 2010-2012. Few cases of multi-drug resistant tuberculosis were identified (18; 1.7%). Compared to 12-loci, 24-loci MIRU provided improved cluster resolution with 695 (61.6%) and 227 (20.1%) clustered cases identified, respectively. Detailed analysis of the largest cluster identified (an 11 member Beijing cluster) revealed wide geographic diversity in the absence of documented social contact.

CONCLUSIONS

EAI strains of M. tuberculosis recently overtook Beijing family as a prevalent cause of tuberculosis in NSW, Australia. This lineage appeared to be less commonly related to multi-drug resistant tuberculosis as compared to Beijing strain lineage. The resolution provided by 24-loci MIRU typing was insufficient for reliable assessment of transmissions, especially of Beijing family strains.

Genotypes of Mycobacterium tuberculosis isolates in rural China: using MIRU-VNTR and spoligotyping methods

BACKGROUND

The genotypes of Mycobacterium tuberculosis (MTB) have been found to be related to the risk of transmission and the development of drug resistance of this pathogen. Thus, exploring the molecular characteristics of MTB is helpful for understanding and controlling the spread of strains in areas with a high incidence of tuberculosis.

METHODS

We recruited 512 sputum smear-positive tuberculosis patients from 30 counties from 1 April to 30 June 2010; 503 MTB strains were isolated and 497 were successfully genotyped. We genotyped the strains based on a new 15-locus mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) method in combination with spacer-oligonucleotide typing (spoligotyping) technology.

RESULTS

Based on spoligotyping, 487 strains displayed known patterns, and 10 were absent from the current global spoligotyping database (SpolDB4). The predominant spoligotypes belonged to the Beijing or Beijing-like family (81.1%). When we used the new 15-locus (MIRU-15) set for the MIRU-VNTR analysis, 388 different patterns were identified, including 46 clusters and 342 unique patterns. The combination of spoligotyping and MIRU-15 demonstrated a high discriminatory power. The proportion of clusters varied significantly between the Beijing and non-Beijing family strains, but no significant association was observed between multidrug resistance and Beijing family strains.

CONCLUSIONS

The present study demonstrated that the Beijing family strains are the most prevalent in rural China. Spoligotyping in combination with the new MIRU-15 technique is useful for the epidemiological analysis of MTB transmission and could be used as a first-line method for the large-scale genotyping of MTB.

Mycobacterium tuberculosis of the RDRio genotype is the predominant cause of tuberculosis and associated with multidrug resistance in Porto Alegre City, South Brazil

Spoligotyping has shown Mycobacterium tuberculosis strains to be composed of different lineages, and some of them are not just geographically restricted but also affect specific ethnic populations and are associated with outbreaks and drug resistance. We recently described a particular subtype within the Latin American-Mediterranean (LAM) family, called RD(Rio), widespread in Brazil. Moreover, recent data also indicate that RD(Rio) is present in many countries on all continents and is associated with cavitary disease and multidrug resistance (MDR). To further explore the relationship between RD(Rio) and MDR, we conducted a study in a tuberculosis (TB) reference center responsible for the care of MDR patients in Rio Grande do Sul, the southernmost Brazilian state. From a collection of 237 clinical isolates, RD(Rio) alone was responsible for one-half of all MDR cases, including one large group composed of strains with identical IS6110-restriction fragment length polymorphism (RFLP) and having the LAM5 signature. We additionally had complete data records for 96 patients and could make comparisons between the presence and absence of RD(Rio). No difference in clinical, radiological or laboratory features was observed, but a significantly greater number of cases with MDR were described in patients infected with an RD(Rio) strain (P = 0.0015). Altogether, RD(Rio) was responsible for 38% of all TB cases. These data support and confirmed previous findings that RD(Rio) is the main agent responsible for TB in Brazil and is associated with drug resistance. Considering that RD(Rio) is a globally distributed genotype, such findings raise concern about the increase in MDR in certain human populations.

Opportunity for healthy ageing: lessening the burden of adult pneumococcal disease in Central and Eastern Europe, and Israel

The population of the Region (Central Europe, Eastern Europe, and Israel) is ageing, necessitating preventative programmes to maintain a healthy and active lifestyle in older age groups. Invasive pneumococcal disease (including bacteremic pneumonia, bacteremia without a focus, and meningitis) has higher incidence, morbidity and mortality in older adults and is a substantial public health burden in the ageing population. Surveillance in the Region establishes a significant burden in older adults of invasive pneumococcal disease (IPD), which still appears to be under-estimated as compared with other countries, and this warrants an improvement in surveillance systems. The largest proportion of IPD in adults is bacteremic pneumonia. Community-acquired pneumonia (CAP), largely attributable to S. pneumoniae, can be bacteremic or non-bacteremic; the non-bacteremic forms of CAP also represent a significant burden in the Region. The burden of pneumococcal disease can be reduced with programmes of effective vaccination. Recommendations on pneumococcal vaccination in adults vary widely across the Region. The main barrier to implementation of vaccination programmes is low awareness among healthcare professionals on serious heatlh consequences of adult pneumococcal disease and of vaccination options. The Expert Panel calls on healthcare providers in the Region to improve pneumococcal surveillance, optimize and disseminate recommendations for adult vaccination, and support awareness and education programmes about adult pneumococcal disease.

Molecular typing of Mycobacterium tuberculosis isolates circulating in Jiangsu province, China

Background

Globally, China is the second place with high burden of tuberculosis (TB). To explore the characteristics of the pathogens of Mycobacterium tuberculosis (MTB) circulating in this area is helpful for understanding and controlling the spread of the strains. Recent developments in molecular biology have allowed prompt identification and tracking specific strains of MTB spreading through the population.

Methods

Spacer-oligonucleotide typing (spoligotyping) and mycobacterial interspersed repetitive units variable number tandem repeat (MIRU-VNTR) were performed in combination to yield specific genetic profiles of 260 MTB strains isolated from 30 counties of Jiangsu province in China between June and July 2010. The spoligotyping results were in comparison to the world Spoligotyping Database of Institute Pasteur de Guadeloupe (SpolDB4). Drug susceptibility test (DST) was performed on all strains by proportion method on Lowenstein-Jensen (LJ) culture media.

Results

Based on the spoligotyping method, 246 strains displayed known patterns and 14 were absent in the database. Predominant spoligotypes belonged to the Beijing family (80.4%). By using the 24-loci VNTR typing scheme, 224 different patterns were identified, including 20 clusters and 204 unique patterns. The largest clade comprised 195 strains belonging to the Beijing family. The combination of spoligotyping and 24-loci MIRU-VNTR demonstrated maximal discriminatory power. Furthermore, we observed a significant association between Beijing family strains and drug-resistant phenotypes. The Beijing family strains presented increased risks for developing multi-drug resistant TB, with the OR (95% CI) of 11.07(1.45-84.50).

Conclusions

The present study demonstrated that Beijing family isolates were the most prevalent strains circulating in Jiangsu province of China. The utility of spoligotyping in combination with 24-loci MIRU-VNTR might be a useful tool for epidemiological analysis of MTB transmission.

Transmission pattern of drug-resistant tuberculosis and its implication for tuberculosis control in eastern rural China

OBJECTIVE

Transmission patterns of drug-resistant Mycobacterium tuberculosis (MTB) may be influenced by differences in socio-demographics, local tuberculosis (TB) endemicity and efficaciousness of TB control programs. This study aimed to investigate the impact of DOTS on the transmission of drug-resistant TB in eastern rural China.

METHODS

We conducted a cross-sectional study of all patients diagnosed with drug-resistant TB over a one-year period in two rural Chinese counties with varying lengths of DOTS implementation. Counties included Deqing, with over 11 years' DOTS implementation and Guanyun, where DOTS was introduced 1 year prior to start of this study. We combined demographic, clinical and epidemiologic information with IS6110-based restricted fragment length polymorphism (RFLP) and Spoligotyping analysis of MTB isolates. In addition, we conducted DNA sequencing of resistance determining regions to first-line anti-tuberculosis agents.

RESULTS

Of the 223 drug-resistant isolates, 73(32.7%) isolates were identified with clustered IS6110RFLP patterns. The clustering proportion among total drug-resistant TB was higher in Guanyun than Deqing (26/101.vs.47/122; p,0.04), but not significantly different among the 53 multidrug-resistant isolates (10/18.vs.24/35; p,0.35). Patients with cavitary had increased risk of clustering in both counties. In Guanyun, patients with positive smear test or previous treatment history had a higher clustering proportion. Beijing genotype and isolates resistant to isoniazid and/or rifampicin were more likely to be clustered. Of the 73 patients with clustered drug-resistant isolates, 71.2% lived in the same or neighboring villages. Epidemiological link (household and social contact) was confirmed in 12.3% of the clustered isolates.

CONCLUSION

Transmission of drug-resistant TB in eastern rural China is characterized by small clusters and limited geographic spread. Our observations highlight the need for supplementing DOTS with additional strategies, including active case finding at the village level, effective treatment for patients with cavities and drug susceptibility testing for patients at increased risk for drug-resistance.