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Within the framework of epidemiological surveillance by molecular typing tools conducted in the NRL on multi-resistant strains, the application of spoligotyping on a group of 390 strains consisting of 389 DR-MTB strains and 1 susceptible strain isolated from patients made it possible to detect the presence of 15 strains belonging to the Beijing genotype. All 15 strains were genotyped by MTBDRplus. Among the 15 strains, 11 were typed by RFLP and 9 by MIRU-VNTR.After analysis of the profiles obtained by the software MIRU-VNTRplus, two spoligotypes (st No. 1 and st No. 265) and four RFLP profiles and a complete identity profile by MIRU-VNTR, information collected on patients allowed the research team to detect a family tie among patients of three different families, as well as one nosocomial TB transmission.The percentage of Beijing strains found among the patients in this study was 3.8%; this figure does not reflect the reality because it was calculated from an essay on MDR-TB.To get an idea of the prevalence of Beijing TB strains in this country, a more extensive study is currently being considered.

Evidence currently suggests that as a species Mycobacterium tuberculosis exhibits very little genomic sequence diversity. Despite limited genetic variability, members of the M. tuberculosis complex (MTBC) have been shown to exhibit vast discrepancies in phenotypic presentation in terms of virulence, elicited immune response and transmissibility. Here, we used qualitative and quantitative mass spectrometry tools to investigate the proteomes of seven clinically-relevant mycobacterial strains—four M. tuberculosis strains, M. bovis, M. bovis BCG, and M. avium—that show varying degrees of pathogenicity and virulence, in an effort to rationalize the observed phenotypic differences. Following protein preparation, liquid chromatography mass spectrometry (LC MS/MS) and data capture were carried out using an LTQ Orbitrap Velos. Data analysis was carried out using a novel bioinformatics strategy, which yielded high protein coverage and was based on high confidence peptides. Through this approach, we directly identified a total of 3788 unique M. tuberculosis proteins out of a theoretical proteome of 4023 proteins and identified an average of 3290 unique proteins for each of the MTBC organisms (representing 82% of the theoretical proteomes), as well as 4250 unique M. avium proteins (80% of the theoretical proteome). Data analysis showed that all major classes of proteins are represented in every strain, but that there are significant quantitative differences between strains. Targeted selected reaction monitoring (SRM) assays were used to quantify the observed differential expression of a subset of 23 proteins identified by comparison to gene expression data as being of particular relevance to virulence. This analysis revealed differences in relative protein abundance between strains for proteins which may promote bacterial fitness in the more virulent W. Beijing strain. These differences may contribute to this strain's capacity for surviving within the host and resisting treatment, which has contributed to its rapid spread. Through this approach, we have begun to describe the proteomic portrait of a successful mycobacterial pathogen. Data are available via ProteomeXchange with identifier PXD004165.

The global presence and rapid dissemination of Beijing genotype of Mycobacterium tuberculosis, makes it an important issue of public health. Its presence and association with multi-drug resistance has been shown in many settings. In present study we tried to find its prevalence and association with drug resistance in North India. One hundred and twenty four M. tuberculosis isolates were analyzed with spoligotyping, further drug susceptibility testing was done by 1% proportional method. Out of these, 11 (8.9%) M. tuberculosis isolates were identified as Beijing and 113 (91.1%) as non-Beijing genotypes. While looking at their drug susceptibility patterns, 6 (54.5%) & 22 (19.5%) were found to be multi drug resistant (MDR) among Beijing and non-Beijing isolates respectively. Our study concluded that the Beijing strains were not so common in north India and these strains do not fully associate with MDR. Keywords: Mycobacterium tuberculosis, Spoligotyping, Beijing, MDR, Drug resistance

Contains fulltext : 110971.pdf (Publisher’s version ) (Open Access) To determine differences in the ability of Mycobacterium tuberculosis strains to withstand antituberculosis drug treatment, we compared the activity of antituberculosis drugs against susceptible Beijing and East-African/Indian genotype M. tuberculosis strains. Beijing genotype strains showed high rates of mutation within a wide range of drug concentrations, possibly explaining this genotype's association with multidrug-resistant tuberculosis. 01 april 2012

Tuberculosis is a global health problem. Continuous efforts are needed to understand the genetic diversity and geographical distribution of Mycobacterium tuberculosis. The objective of this study was to determine the genetic diversity of M. tuberculosis strains in Soshanguve, Pretoria. Eighty-nine isolates that were sputum culture-positive in Mycobacterium Growth Indicator Tube 960®, and positively identifed by Accuprobe Probe assay as M. tuberculosis complex, were used in the study. The samples were sub-cultured on Lowenstein-Jensen (L-J) slants to ensure purity. Spoligotyping was performed, with slight modifcations according to the manufacturer’s specifcations. Genotypic data were compared to the international spoligotyping database 4 (SpolDB4) and that suggested by Streicher et al. Spoligotyping identifed 12 genotypes. Of the 89 isolates studied, 75 could be grouped into 11 clusters. The Beijing genotype family formed the largest group, with 21 isolates (28%). The remaining isolates were distributed am...

Mycobacterium tuberculosis strain W06, analyzed by molecular methods, was classified as a modern Beijing M. tuberculosis strain, the most predominant strain in Taiwan. To our knowledge, this is the first draft genome announcement of a Beijing M. tuberculosis strain in Taiwan.

Emerging Microbes & Infections (2017) 6, e47; doi:10.1038/emi.2017.33; published online 7 June 2017

All known genotypes (3925 spoligoprofiles of M. tuberculosis) were selected using the SITVIT database in nine countries, including countries of the former Soviet Union: Russia, Latvia, Estonia, Poland, Finland, Italy, Portugal, Japan, and Vietnam. The programs SpolTools and DESTUS were used to construct consensus networks to identify the epidemic genotypes of M. tuberculosis in the studied countries. In Russia, Latvia, and Estonia, the Beijing strain was determined as the main epidemic genotype. In Finland, Poland, Portugal, and Italy, all epidemic genotypes belonged to other families. The hypothesis on the explosive nature of the spreading of the Beijing genotype of M. tuberculosis was put forward for Russia and other former Soviet countries in the 20th century. The basic idea of the hypothesis was that the pattern of dissemination of the Beijing genotype occurred at the CER (Chinese Eastern Railway), in the Gulag, and in the civilian society of Soviet Union. The Beijing genotype of M. tuberculosis affected Russian builders of the CER during the end the 19th and early 20th centuries. With the repression of CER builders in the Soviet Union, the Beijing genotype was spread among Gulag prisoners; after 1953, it had spread throughout the civilian society of the entire country. The distribution of epidemic genotypes of M. tuberculosis in the studied countries was interpreted as evidence of the suggested hypothesis.

Objective : To investigate the prevalence of Beijing genotype strains of Mycobacterium tuberculosis in the Kingdom of Saudi Arabia. Methods : We analyzed the available data on a total of 1505 strains isolated during 2002-2005. Results : Spoligotyping results revealed that Beijing family isolates represented 4.5% of all the isolates. Existence of Beijing clade is alarming as this family is known to be multi-drug resistant and transmissible. Conclusions : This study showed that the occurrence of Beijing genotype is associated with young age and drug resistance. The Beijing strains affected both Saudi nationals as well as migrants originating in Asia. The Beijing clade could be responsible for the ongoing transmission of tuberculosis within the community.

Purpose : The purpose of this study was to understand the molecular epidemiology of tuberculosis in Khorasan province of Iran was studied by spoligotyping 113 Mycobacterium tuberculosis isolates. The spoligotyping results were in comparison to the word Spoligotyping Database of Institute Pasteur de Guadeloupe (SpolDB4). Spoligotyping data from Iran has rarely been described and there is limited information on the major circulating clades of M. tuberculosis in Iran. Materials and Methods: Spoligotyping was performed on 113 M. tuberculosis isolates from Mashhad patients between November 2004 and September 2005. Results: The study found 57 spoligopatterns. 17 clusters and 32 true orphan genotype. The biggest cluster with 13 isolates had not been previously reported. The Beijing genotype was seen in eight (7.1%) isolates. Conclusions: Genotyping and Spoligotyping gives a unifying framework for both epidemiology and evolutionary analysis of M. tuberculosis populations.

The Beijing genotype of Mycobacterium tuberculosis has been shown in many settings to be hypervirulent and associated with multi-drug resistance. Its presently global and rapid dissemination makes it an important issue of public health. Here, I present a significantly enlarged update of the MIRU-VNTR global database of the M. tuberculosis Beijing genotype (11 loci). I further attempted to link the observed mycobacterial diversity with relevant events of the known human history. Large water masses have been the most efficient and drastic generators of the genetic divergence between human populations. The same situation appears true also for M. tuberculosis, which general diversity pattern amazingly resembles that of its human host. At the same time, less expected affinities observed between distant populations of M. tuberculosis may reflect hidden patterns of human migrations or yet unknown epidemiological links between distant regions.

Background and purpose: The Beijing genotype is one of the most important strains of Mycobacterium tuberculosis involving outbreaks of tuberculosis in various parts of the world. Unsought regarding Beijing genotype in Iran, is the reason this study is undertaken in order to evaluate the frequency of this genotype in Mashhad.Materials and Methods: This descriptive study was carried out on 113 M.tuberculosis Specimens isolated from patient with pulmonary tuberculosis in hygienic centers, located at Ghaem and Imam Reza hospitals in the City of Mashhad. In this study, Beijing genotypes were detected with PCR-based method, and spoligotyping. Results were processed with descriptive statistics and CI was evaluated.Results: Beijing genotype was detected in 8 specimens of all the 113 isolated M.tuberculosis strains (7.1%, CI 95%, 2.36-11.84). Out of 8 isolated specimens, 5 isolates belonged to Afghan patients and 3 specimens were isolated from Iranian patients. Out of 8 patients that were infected with Beijing genotype, 2 patients were male and 6 patients were female.Conclusion: Although the rate of Beijing family is low in Iran, in comparison to other Asian countries, however, one needs to adopt a suitable policy in order to prevent its spread.

We compared the population structure and drug resistance patterns of the Mycobacterium tuberculosis strains currently circulating in the Beijing area of China. One hundred thirteen of 123 strains belonged to the Beijing family genotypes defined by spoligotyping. The Beijing genotype strains were further subdivided into old and modern sublineages on the basis of NTF locus analysis. A stronger association with resistance to the more recently introduced antituberculosis drugs has been observed for old versus modern strains of the Beijing genotype, suggesting that its different sublineages may differ in their mechanisms of adaptation to drug selective pressure.

Mycobacterium tuberculosis strains of the Beijing genotype have been involved in various outbreaks of multidrug-resistant tuberculosis. Some studies suggest that the infection with the Beijing genotype is associated with a different host immune response. Since this might also lead to a different chest X-ray (CXR) presentation, we compared CXRs of patients with pulmonary tuberculosis, 33 of whom were infected with the Beijing genotype and 76 with other genotypes. No significant differences were detected. We conclude that the Beijing genotype is not associated with a different CXR presentation. (C) 2004 Elsevier Ltd. All rights reserved

To determine whether the Beijing genotype of Mycobacterium tuberculosis is emerging in the Netherlands, we collected data on 6,829 patients during 1993 to 2000. Six percent had the Beijing genotype. This genotype was associated with diagnosis in recent years, young age, nationality, and multidrug resistance.

The molecular epidemiology of tuberculosis (TB) in Finland was studied by spoligotyping 380 Mycobacterium tuberculosis isolates. The isolates were obtained during a 1-year study period from July 2000 to June 2001 and represented 90% of new M. tuberculosis findings by culture in the whole country during the study period. The spoligotyping results were compared to the World Spoligotyping Database of the Institut Pasteur de Guadeloupe, which contains data from >14,000 M. tuberculosis isolates obtained worldwide. A total of 138 different spoligotypes were identified among the 380 M. tuberculosis isolates. Thirty-eight (10%) isolates had unique spoligotypes, while 342 (90%) isolates belonged to 100 shared types. The four most common spoligotypes caused approximately one-third of the Finnish TB cases. Forty-seven of the 138 (34.1%) spoligotypes and 61 (16.1%) of the 380 M. tuberculosis isolates had spoligotypes that had not been previously reported. Only four (1.1%) patients were infected with an isolate belonging to the Beijing genotype. The characterization of Finnish M. tuberculosis isolates by spoligotyping shows that ubiquitous spoligotypes were common, but many spoligotypes specific to Finland were also found. However, Beijing family isolates were rarely encountered, although this spoligotype is predominant in our eastern and southern neighbors.

We describe a multiplex PCR assay to detect the Mycobacterium tuberculosis Beijing genotype variant B0/W148, which is considered a “successful” clone of M. tuberculosis , widespread in Russia. Specificity and sensitivity of the assay were 100% based on the analysis of a collection of 516 M. tuberculosis isolates of different genotypes and origins. This assay may be used for accurate and simple detection and surveillance of this clinically and epidemiologically important variant of M. tuberculosis .

Summary The influence of Mycobacterium tuberculosis (MTB) lineages/sublineages on unfavorable tuberculosis (TB) treatment outcomes is poorly understood. We investigated the effects of Beijing genotype sublineages and other factors contributing to treatment outcome. Patients newly diagnosed with sputum smear-positive and culture-positive TB in Hanoi, Vietnam, participated in the study. After receiving anti-TB treatment, they were intensively followed up for the next 16 months. MTB isolates collected before treatment were subjected to drug susceptibility testing, and further analyzed to determine MTB (sub) lineages and their clonal similarities. Of 430 patients, 17 had treatment failure and 30 had TB recurrence. Rifampicin resistance was associated with treatment failure {adjusted odds ratio = 6.64 [95% confidence interval (CI), 1.48–29.73]}. The modern Beijing genotype was significantly associated with recurrent TB within 16 months [adjusted hazard ratio = 3.29 (95% CI, 1.17–9.27)], particularly after adjustment for the relevant antibiotic resistance. Human immunodeficiency virus coinfection and severity on chest radiographs were not significantly associated with unfavorable outcomes. Our findings provide further understanding of the influence of MTB strains on unfavorable treatment outcomes. Multiple risk factors should be considered for the optimal management of TB.

Mycobacterium tuberculosis Beijing genotype strains are rapidly disseminating, frequently hypervirulent, and multidrug resistant. Here, we describe a method for their rapid detection by real-time PCR that targets the specific IS 6110 insertion in the dnaA-dnaN genome region. The method was evaluated with a geographically and genetically diverse collection representing areas in East Asia and the former Soviet Union in which the Beijing genotype is endemic and epidemic (i.e., major foci of its global propagation) and with clinical specimens.

In a tuberculosis (TB) program in the Central Penitentiary Hospital of Azerbaijan, we analyzed 65 isolates of Mycobacterium tuberculosis by IS6110-based restriction fragment-length polymorphism (RFLP) and spoligotyping. From 11 clusters associated with 33 patients, 31 isolates had an IS6110-based banding pattern characteristic of the Beijing genotype of M. tuberculosis. In addition, 15 M. tuberculosis isolates with similar RFLP patterns constituted a single group by spoligotyping, matching the Beijing genotype. Multidrug resistance, always involving isoniazid and rifampin, was seen in 34 (52.3%) of 65 isolates, with 28 belonging to the Beijing genotype.

The Beijing genotype of Mycobacterium tuberculosis has frequently been found to be associated with drug resistance. Mutation analysis of the genes encoding 16S rRNA ( rrs ) and ribosomal protein S12 ( rpsL ) revealed a high frequency (97/102; 95.1%) of alterations in streptomycin-resistant M. tuberculosis isolates from Singapore, with rpsL K43R being the most common rpsL mutation (82/92; 89%), which was significantly associated with Beijing strains compared to non-Beijing strains (odds ratio=10.88, 95% confidence interval=3.48–34.1). This is the first study to report the association of Beijing strains with the rpsL K43R mutation in STR-resistant M. tuberculosis isolates with de novo resistance, as determined by clustering analysis.

To assess whether the Mycobacterium tuberculosis Beijing genotype is emerging in Vietnam we analyzed 563 isolates from new cases by spoligotyping and examined the association between the genotype and age resistance and BCG vaccination status. Three hundred one (54%) patients were infected with Beijing genotype strains. The genotype was associated with younger age (and hence with active transmission) and with isoniazid and streptomycin resistance but not with BCG vaccination. (authors)

The impact of W-Beijing genotype Mycobacterium tuberculosis on treatment outcome was evaluated in 249 newly diagnosed tuberculosis patients. No significant difference in the treatment outcome was found between the W-Beijing and non-W-Beijing groups. However, a poor outcome was more common in the elderly patients (≥65 years) infected with the W-Beijing strain.

In this work, we studied the variation in the gyrA and gyrB genes in ofloxacin- and multidrug-resistant Mycobacterium tuberculosis strains circulating in northwest Russia. Comparison with spoligotyping data suggested that similar to the spread of multidrug-resistant tuberculosis, the spread of fluoroquinolone-resistant tuberculosis in Russia may be due, at least partly, to the prevalence of the Beijing genotype in a local population of M. tuberculosis .

Background Mycobacterium tuberculosis Beijing strains are characterized by a large number of IS6110 copies, suggesting the potential implication of this element in the virulence and capacity for rapid dissemination characteristic of this family. This work studies the insetion points of IS6110 in high-copy clinical isolates specifically focusing on the Beijing genotype. Results In the present work we mapped the insertion points of IS6110 in all the Beijing strains available in the literature and in the DNA sequence databases. We generated a representative primer collection of the IS6110 locations, which was used to analyse 61 high-copy clinical isolates. A total of 440 points of insertion were identified and analysis of their flanking regions determined the exact location, the direct repeats (DRs), the orientation and the distance to neighboring genes of each copy of IS6110. We identified specific points of insertion in Beijing strains that enabled us to obtain a dendrogram that groups the Beijing genotype. Conclusions This work presents a detailed analysis of locations of IS6110 in high-copy clinical isolates, showing points of insertion present with high frequency in the Beijing family and absent in other strains.

Of 75 MDR isolates from Fujian Province, the sensitivity of RIF, INH, EMB, SM, OFLX and KAN resistance by DNA sequencing was 96.0%, 96.0%, 66.7%, 66.0%, 84.2% and 75.0%, respectively. We also identified that minority mutations in the mixed Mycobacterium tuberculosis population may be responsible for two "false-negative" results. In addition, Beijing genotype is still the predominant sublineage in the MDR TB cases from Fujian.

This study describes a comparative analysis of the Beijing mycobacterial interspersed repetitive unit types of Mycobacterium tuberculosis isolates from Cape Town, South Africa, and East Asia. The results show a significant association between the frequency of occurrence of strains from defined Beijing sublineages and the human population from whom they were cultured ( P < 0.0001).

Multidrug- (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) are reported to gradually spread across European countries with low TB prevalence including France. Some isolates may even accumulate traits of resistance in addition to the XDR profile, as a result of therapeutic mismanagement. We report here the first case of XDR TB in Marseilles and discuss the potential effectiveness of sulfamide treatment in such cases.

Summary Phylogenetic analysis has shown that Beijing genotype strains can be grouped into at least 7 different sublineages. We aimed to test the hypothesis that the virulence of Beijing genotype strains differed among members of the different sublineages and that the level of virulence correlated with their ability to spread and cause disease. BALB/c mice were infected with Beijing strains representative of the different lineages and of different epidemiological characteristics (transmitted vs. non-transmitted). Survival times, lung pathology, bacterial load and immunology kinetics were evaluated at defined intervals post-infection. Transmissibility was determined by co-housing infected and uninfected mice in close contact for 1–2 months. The results show that mice infected with the highly transmitted Beijing strains began showing mortality 3 weeks post-infection and all had died by 5 weeks, suggesting high virulence phenotypes. In contrast, >80% of mice infected with the non-transmitted strains survived 4 months post-infection, suggesting low virulence phenotypes. Our co-housing transmission model confirmed these virulence phenotypes. Extensive tissue damage and the induction of lower levels of IFNγ and iNOS expression, as well as high but ephemeral TNFα expression were associated with the high virulence phenotype. In contrast, minimal tissue damage and progressive expression of IFNγ and TNFα were associated with the low virulence phenotype. Both virulence phenotypes induced similar levels of IL-4 expression during the early stages of infection after which the high virulence strain induced significantly higher levels of IL-4 expression. In conclusion, this study demonstrates that Beijing genotype strains display a spectrum of virulence phenotypes in mice which mimic their epidemiological characteristics. Both transmissible and non-transmissible strains may exist in the same sublineage.

These case investigations may help identify routes of transmission., Molecular surveillance of multidrug-resistant tuberculosis (MDR TB) was implemented in Europe as case reporting in 2005. For all new MDR TB cases detected from January 2003 through June 2007, countries reported case-based epidemiologic data and DNA fingerprint patterns of MDR TB strains when available. International clusters were detected and analyzed. From 2003 through mid-2007 in Europe, 2,494 cases of MDR TB were reported from 24 European countries. Epidemiologic and molecular data were linked for 593 (39%) cases, and 672 insertion sequence 6110 DNA fingerprint patterns were reported from 19 countries. Of these patterns, 288 (43%) belonged to 18 European clusters; 7 clusters (242/288 cases, 84%) were characterized by strains of the Beijing genotype family, including the largest cluster (175/288 cases, 61%). Both clustering and the Beijing genotype were associated with strains originating in eastern European countries. Molecular cluster detection contributes to identification of transmission profile, risk factors, and control measures.

Using geographic information system and molecular tools, we characterized a possible outbreak of tuberculosis caused by Mycobacterium tuberculosis Beijing strain in 17 patients in Cotonou, Benin, during July 2005October 2006. Most patients lived or worked in the same area and frequented the same local drinking bar. The isolates were streptomycin resistant.

The aim of this study was the molecular characterization of primary drug-resistant Mycobacterium tuberculosis strains in Thailand. We examined a group of M. tuberculosis isolates from newly registered tuberculosis (TB) cases, collected at the largest university hospital, the Siriraj Hospital, in Thailand. Of 76 selected drug-resistant M. tuberculosis strains recovered from previously untreated pulmonary TB patients whose sputum samples were sent to this hospital, 29 (38%) were single-drug resistant, 26 (34%) multidrug resistant and two (2.6%) extensively drug resistant. Fifty (66%) strains belonged to Beijing genotype. The study demonstrate a severe problem of drug resistance among recently detected TB patients, and two large clusters of genetically similar strains indicated ongoing transmission of drug-resistant TB.

The frequency of the Beijing genotype of Mycobacterium tuberculosis as a cause of tuberculosis (TB) in South America was determined by analyzing genotypes of strains isolated from patients that had been diagnosed with the disease between 1997 and 2003 in seven countries of the subcontinent. In total, 19 of the 1,202 (1.6%) TB cases carried Beijing isolates, including 11 of the 185 patients from Peru (5.9%), five of the 512 patients from Argentina (1.0%), two of the 252 Brazilian cases (0.8%), one of the 166 patients from Paraguay (0.6%) and none of the samples obtained from Chile (35), Colombia (36) and Ecuador (16). Except for two patients that were East Asian immigrants, all cases with Beijing strains were native South Americans. No association was found between carrying a strain with the Beijing genotype and having drug or multi-drug resistant disease. Our data show that presently transmission of M. tuberculosis strains of the Beijing genotype is not frequent in Latin America. In addition, the lack of association of drug resistant TB and infection with M. tuberculosis of the Beijing genotype observed presently demands efforts to define better the contribution of the virulence and lack of response to treatment to the growing spread of Beijing strains observed in other parts of the world.

In a recent paper by Rao et al. (3), the easy and rapid mycobacterial interspersed repetitive unit (MIRU) locus 26 PCR assay was found to be 100% specific and sensitive for the discrimination of the Beijing genotype Mycobacterium tuberculosis strains from the non-Beijing strains based on the assumption that all Beijing strains have seven copies and non-Beijing strains have fewer or more than seven MIRU copies at locus 26. Unfortunately, however, it is known that not all Beijing isolates carry seven MIRU copies at locus 26 (2, 4). Particularly, in some geographic regions, such as the countries of the former USSR, Beijing genotype strains with fewer than seven MIRU copies at locus 26 are in striking predominance over strains with seven copies (2). Recently, we showed that Beijing genotype strains recovered in Istanbul were carried over from the countries of the former USSR, and of the 46 Beijing genotype strains, 37 strains were found to have fewer than seven MIRU copies at locus 26 (1). After having performed spoligotyping and MIRU typing for more than 2,000 M. tuberculosis strains in Istanbul, we also encountered some non-Beijing strains which had seven repeats at MIRU locus 26. These non-Beijing strains with seven repeats at locus 26 were of the T1, LAM-9, Haarlem 1, CAS 1, 703740004000760, 703777740003371, and 777777774760771 spoligotypes. In conclusion, the sensitivity and specificity of the MIRU locus 26 PCR assay may not be 100% as was found in this study (3), and this assay seems to be far from reliable as a screening tool to identify and discriminate Beijing genotype strains from non-Beijing strains, since there are Beijing genotype strains with fewer or more than seven repeats at locus 26 and, conversely, non-Beijing strains with seven repeats.

Rao et al. ([3][1]) described a method to identify Mycobacterium tuberculosis strains of the Beijing genotype. The authors suggested using simple PCR of mycobacterial interspersed repetitive unit-variable-number tandem repeat (MIRU-VNTR) locus 26 to identify these strains. This suggestion is based

Background After the collapse of the Soviet Union, dramatically increasing rates of tuberculosis and multidrug-resistant tuberculosis (MDR-TB) have been reported from several countries. This development has been mainly attributed to the widespread breakdown of TB control systems and declining socio-economic status. However, recent studies have raised concern that the Beijing genotype of Mycobacterium tuberculosis might be contributing to the epidemic through its widespread presence and potentially enhanced ability to acquire resistance. Methods A total of 397 M. tuberculosis strains from a cross sectional survey performed in the Aral Sea region in Uzbekistan and Turkmenistan have been analysed by drug susceptibility testing, IS6110 fingerprinting, and spoligotyping. Results Fifteen isolates showed mixed banding patterns indicating simultaneous infection with 2 strains. Among the remaining 382 strains, 152 (40%) were grouped in 42 clusters with identical fingerprint and spoligotype patterns. Overall, 50% of all isolates were Beijing genotype, with 55% of these strains appearing in clusters compared to 25% of non-Beijing strains. The percentage of Beijing strains increased with increasing drug resistance among both new and previously treated patients; 38% of fully-susceptible isolates were Beijing genotype, while 75% of MDR-TB strains were of the Beijing type. Conclusion The Beijing genotype is a major cause of tuberculosis in this region, it is strongly associated with drug resistance, independent of previous tuberculosis treatment and may be strongly contributing to the transmission of MDR-TB. Further investigation around the consequences of Beijing genotype infection for both tuberculosis transmission and outcomes of standard short course chemotherapy are urgently needed.

The relationship of Mycobacterium tuberculosis Beijing genotype with tuberculosis relapse was examined. Beijing strains were detected from 32 out of 45 (71%) relapsed cases and 148 out of 290 (51%) non-relapsed cases. Multivariate logistic regression analysis revealed that Beijing genotype was significantly associated with tuberculosis relapse (OR 2·64, 95% CI 1·30–5·34, P=0·005).

In a 7-year population-based study in Malawi, we showed that Beijing genotype tuberculosis (TB) increased as a proportion of TB cases. All the Beijing genotype strains were fully drug sensitive. Contact histories, TB type, and case-fatality rates were similar for Beijing and non-Beijing genotype TB.