There is no correlation between sublineages and drug resistance of Mycobacterium tuberculosis Beijing/W lineage clinical isolates in Xinjiang, China

Opinion review of drug resistant tuberculosis in West Africa: tackling the challenges for effective control

Drug-resistant (DR) tuberculosis (TB) is a major public health concern globally, complicating TB control and management efforts. West Africa has historically faced difficulty in combating DR-TB due to limited diagnostic skills, insufficient access to excellent healthcare, and ineffective healthcare systems. This has aided in the emergence and dissemination of DR Mycobacterium tuberculosis complex (MTBC) strains in the region. In the past, DR-TB patients faced insufficient resources, fragmented efforts, and suboptimal treatment outcomes. However, current efforts to combat DR-TB in the region are promising. These efforts include strengthening diagnostic capacities, improving access to quality healthcare services, and implementing evidence-based treatment regimens for DR-TB. Additionally, many West African National TB control programs are collaborating with international partners to scale up laboratory infrastructure, enhance surveillance systems, and promote infection control measures. Moreso, novel TB drugs and regimens, such as bedaquiline and delamanid, are being introduced to improve treatment outcomes for DR-TB cases. Despite these obstacles, there is optimism for the future of DR-TB control in West Africa. Investments are being made to improve healthcare systems, expand laboratory capacity, and support TB research and innovation. West African institutions are now supporting knowledge sharing, capacity building, and resource mobilization through collaborative initiatives such as the West African Network for TB, AIDS, and Malaria (WANETAM), the West African Health Organization (WAHO), and other regional or global partners. These efforts hold promise for improved diagnostics, optimized treatment regimens, and provide better patient outcomes in the future where drug-resistant TB in WA can be effectively controlled, reducing the burden of the disease, and improving the health outcomes of affected individuals.

Evolution and epidemic success of Mycobacterium tuberculosis in eastern China: evidence from a prospective study

BACKGROUND

Lineage distribution of Mycobacterium tuberculosis (Mtb) isolates is strongly associated with geographically distinct human populations, and its transmission can be further impacted by the bacterial genome. However, the epidemic success of Mtb isolates at an individual level was unknown in eastern China. Knowledge regarding the emergence and transmission of Mtb isolates as well as relevant factors may offer a new solution to curb the spread of the disease. Thus, this study aims to reveal the evolution and epidemic success of Mtb isolates in eastern China.

RESULTS

Of initial 1040 isolates, 997 were retained after removing duplicates and those with insufficient sequencing depth. Of the final samples, 733 (73.52%) were from Zhejiang Province, and 264 (26.48%) were from Shanghai City. Lineage 2 and lineage 4 accounted for 80.44% and 19.56%, with common ancestors dating around 7017 years ago and 6882 years ago, respectively. Sub-lineage L2.2 (80.34%) contributed the majority of total isolates, followed by L4.4 (8.93%) and L4.5 (8.43%). Additionally, 51 (5.12%) isolates were identified to be multidrug-resistant (MDR), of which 21 (29.17%) were pre-extensively drug-resistant (pre-XDR). One clade harboring katG S315T mutation may date back to 65 years ago and subsequently acquired mutations conferring resistance to another five antibiotic drugs. The prevalence of compensatory mutation was the highest in pre-XDR isolates (76.19%), followed by MDR isolates (47.06%) and other drug-resistant isolates (20.60%). Time-scaled haplotypic density analyses suggested comparable success indices between lineage 2 and lineage 4 (P = 0.306), and drug resistance did not significantly promote the transmission of Mtb isolates (P = 0.340). But for pre-XDR isolates, we found a higher success index in those with compensatory mutations (P = 0.025). Mutations under positive selection were found in genes associated with resistance to second-line injectables (whiB6) and drug tolerance (prpR) in both lineage 2 and lineage 4.

CONCLUSIONS

Our study demonstrates the population expansion of lineage 2 and lineage 4 in eastern China, with comparable transmission capacity, while accumulation of resistance mutations does not necessarily facilitate the success of Mtb isolates. Compensatory mutations usually accompany drug resistance and significantly contribute to the epidemiological transmission of pre-XDR strains. Prospective molecular surveillance is required to further monitor the emergence and spread of pre-XDR/XDR strains in eastern China.

Recent Transmission and Prevalent Characterization of the Beijing Family Mycobacterium tuberculosis in Jiangxi, China

The Beijing genotype is the most common type of tuberculosis in Jiangxi Province, China. The association of population characteristics and their prevalence in the development of recent transmission is still unclear. 1,433 isolates were subjected to drug-resistant tests and MIRU-VNTR analysis. We compared differences in demographic characteristics and drug resistance patterns between the Beijing and non-Beijing family strains. We also explored the association of the clustering rate with the Beijing genotype of Mycobacterium tuberculosis. The Beijing genotype was dominant (78.16%). The results of MIRU-VNTR showed that 775 of 1,433 strains have unique patterns, and the remaining gather into 103 clusters. A recent transmission rate was 31.54% (452/1,433). The Beijing genotype strains were more likely to spread among the recurrent population (p = 0.004), people less than 50 years of age (p = 0.02 or 0.003), and the personnel in the northern regions (p = 0.03). Drug resistance patterns did not show significant differences between Beijing and non-Beijing genotype isolates. Furthermore, we found that HIV-positive cases had a lower clustering rate (p = 0.001). Our results indicated that the recurrent population and people under 50 years of age were more likely to be infected with the Beijing genotype of M. tuberculosis. The strains from the Beijing family were easier to cluster compared to strains isolated from the non-Beijing family. Social activity and AIDS substantially impacted the clustering rate of the Beijing genotype of M. tuberculosis. Multidrug resistant M. tuberculosis affected Beijing genotype transmission.

Evaluation of the frequency of mutation genes in multidrug-resistant tuberculosis (MDR-TB) strains in Beijing, China

The aim of this study was to explore the frequency and distribution of gene mutations that are related to isoniazid (INH) and rifampin (RIF)-resistance in the strains of the multidrug-resistant tuberculosis (MDR-TB) Mycobacterium tuberculosis (M.tb) in Beijing, China. In this retrospective study, the genotypes of 173 MDR-TB strains were analysed by spoligotyping. The katG, inhA genes and the promoter region of inhA, in which genetic mutations confer INH resistance; and the rpoB gene, in which genetic mutations confer RIF resistance, were sequenced. The percentage of resistance-associated nucleotide alterations among the strains of different genotypes was also analysed. In total, 90.8% (157/173) of the MDR strains belonged to the Beijing genotype. Population characteristics were not significantly different among the strains of different genotypes. In total, 50.3% (87/173) strains had mutations at codon S315T of katG; 16.8% (29/173) of strains had mutations in the inhA promoter region; of them, 5.5% (15/173) had point mutations at -15 base (C→T) of the inhA promoter region. In total, 86.7% (150/173) strains had mutations at rpoB gene; of them, 40% (69/173) strains had mutations at codon S531L of rpoB. The frequency of mutations was not significantly higher in Beijing genotypic MDR strains than in non-Beijing genotypes. Beijing genotypic MDR-TB strains were spreading in Beijing and present a major challenge to TB control in this region. A high prevalence of katG Ser315Thr, inhA promoter region (-15C→T) and rpoB (S531L) mutations was observed. Molecular diagnostics based on gene mutations was a useful method for rapid detection of MDR-TB in Beijing, China.

Geno-Spatial Distribution of Mycobacterium Tuberculosis and Drug Resistance Profiles in Myanmar-Thai Border Area

Worldwide, studies investigating the relationship between the lineage of Mycobacterium tuberculosis (MTB) across geographic areas has empowered the "End TB" program and understand transmission across national boundaries. Genomic diversity of MTB varies with geographical locations and ethnicity. Genomic diversity can also affect the emergence of drug resistance. In Myanmar, we still have limited genetic information about geographical, ethnicity, and drug resistance linkage to MTB genetic information. This study aimed to describe the geno-spatial distribution of MTB and drug resistance profiles in Myanmar-Thailand border areas. A cross-sectional study was conducted with a total of 109 sequenced isolates. The lineages of MTB and the potential associated socio-demographic, geographic and clinical factors were analyzed using Fisher's exact tests. p value of statistically significance was set at < 0.05. We found that 67% of the isolates were lineage 1 (L1)/East-African-Indian (EAI) (n = 73), followed by lineage 2 (L2)/Beijing (n = 26), lineage 4 (L4)/European American (n = 6) and lineage 3 (L3)/Delhi/Central Asian (n = 4). "Gender", "type of TB patient", "sputum smear grading" and "streptomycin resistance" were significantly different with the lineages of MTB. Sublineages of L1, which had never been reported elsewhere in Myanmar, were detected in this study area. Moreover, both ethnicity and lineage of MTB significantly differed in distribution by patient location. Diversity of the lineage of MTB and detection of new sublineages suggested that this small area had been resided by a heterogeneous population group who actively transmitted the disease. This information on distribution of lineage of MTB can be linked in the future with those on the other side of the border to evaluate cross-border transmission.

24-locus MIRU-VNTR and Spoligotyping analysis of drug-resistant Mycobacterium tuberculosis strains isolated from Northeastern Thailand

Tuberculosis, caused by Mycobacterium tuberculosis (MTB) infection, remains a global health problem with increased concerns due to drug-resistant tuberculosis. However, molecular genotyping profiles may give insight of the transmission of TB in a particular region. The present study aimed to characterize the genetic diversity of drug-resistant MTB and evaluate primer sets applied for the epidemiological study of circulating MTB in Northeastern Thailand. A total of 92 MTB isolates, resistant to rifampicin and/or isoniazid, were collected from the Office of Disease Prevention and Control between 2013 and 2016. All isolates were genotyped by 24-locus MIRU-VNTR typing combined with spoligotyping. We also analyzed the distributions of drug susceptibility pattern and demographic data among different genotypes. In comparison with different loci sets, discriminatory power based on 12, 15, 24 standard primers were investigated. Eighty-six particular profiles were found; among the patterns, two clusters were produced in 8 strains. East African Indians (EAI) were the most prevalent strains (33 isolates, 35.87%) followed by Beijing (30 isolates, 32.61%), with 23 unknown isolates strains also found. The HGDI based on combination of 24 loci analysis and spoligotyping was 0.9962. The number of tandem repeat generated was highly discriminant (HGDI>0.6) at locus 580 (0.66), 960 (0.67), 2163b (0.73), 2165 (0.62), 2461 (0.68) 3690 (0.73) and 4052 (0.79), respectively. In contrast, the diversity at locus 154 and 2059 was not revealed. The results emphasized that 24-locus MIRU-VNTR and spoligotyping could be useful for epidemiological surveillance of drug-resistant MTB in this region. At a given allelic diversity, 7 primer sets containing MIRU04, MIRU10, QUB2163b, ETRA, ETRB, Mtub39 and QUB26 may be considered for screening the VNTR patterns. In addition, this study gathered both demographics and genotypic data within the same investigation for further tuberculosis prevention and control.

Genetic diversity and drug resistance of Mycobacterium tuberculosis in Yunnan, China

Background

China is a country with high burden of tuberculosis (TB), especially drug‐resistant TB (DR‐TB), which is still a serious health problem in Yunnan Province. Mycobacterium tuberculosis (MTB) is the pathogenic microorganism of TB. The epidemiological characteristics of MTB strains in local areas need to be described.

Methods

A total of 430 clinical MTB isolates were collected from Yunnan Province and genotyped through the method of 24‐locus mycobacterial interspersed repetitive unit‐variable number tandem DNA repeats (MIRU‐VNTR).

Results

The genotypes of the 24 loci showed abundantly genetic diversity, and allelic diversity index (h) of these loci varied from 0.012 to 0.817. Among the 430 strains, 30 clusters and 370 unique genotypes were identified. Beijing family was the predominant lineage (70.47%) in Yunnan MTB strains, and the other lineages contained T family (5.81%), MANU2 (0.70%), LAM (3.26%), CAS (0.23%), New‐1 (8.37%), and some unknown clades (11.16%). A total of 74 TB strains were identified as drug resistance through drug susceptibility testing (DST), including 38 multidrug‐resistant TB (MDR‐TB) and 36 single‐drug‐resistant TB (SDR‐TB). The frequency of MDR‐TB strains was significantly higher in Beijing family (10.89%) than that in non‐Beijing family (3.94%, P = 0.032).

Conclusions

Although MTB strains showed high genetic diversity in Yunnan, China, the Beijing family was still the dominant strain. A high frequency of MDR‐TB strains was recorded in the Beijing family.

Characterization of Mycobacterium tuberculosis strains in Beijing, China: drug susceptibility phenotypes and Beijing genotype family transmission

Background

The most prevalent strains of Mycobacterium tuberculosis (M.tb) in Beijing belong to the Beijing genotype family. The influence of Beijing genotype prevalence on the development of drug resistance, and the association of infection with Beijing genotype M.tb with population characteristics, in Beijing, however, are still unclear.

Methods

In this retrospective study, 1189 isolates were subjected to drug susceptibility testing (DST) and molecular epidemiological analysis, and differences in the percentage of drug resistance between Beijing and non-Beijing genotype strains were compared. The association between the occurrence of drug resistance and the prevalence of Beijing genotype M.tb was analyzed using statistical methods.

Results

The Beijing genotype family was the dominant genotype (83.3%) among the 1189 M.tb isolates. Beijing genotype M.tb strains were more likely to spread among males [p = 0.018, OR (95% CI):1.127(1.004–1.264)] and people in the 45–64 age group [p = 0.016, OR (95% CI): 1.438 (1.027–2.015)]. On the contrary, non-Beijing genotype M.tb strains were more probably disseminated among the over 65 [p = 0.005, OR (95% CI):0.653 (0.474–0.9)] and non-resident population [p = 0.035, OR (95% CI):1.185(0.985–1.427)]. DST results showed that 849 (71.4%) strains were fully sensitive to first-line drugs, while 340 (28.6%) strains were resistant to at least one drug, and 9% (107/1189) were MDR-TB. The frequency of INH-resistance among Beijing genotype strains was significantly lower than that among non-Beijing genotype strains (p = 0.032). In addition, the Beijing genotype family readily formed clusters.

Conclusions

Our findings indicate that male and middle-aged people were more probably be infected by Beijing genotype M.tb, older people and non-residents were more probably be infected by non-Beijing genotype M.tb. The high percentage of resistance to INH occurring in non-Beijing genotype strains suggested that non-Beijing genotype strains should be given much more interest in Beijing.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3578-7) contains supplementary material, which is available to authorized users.

Genetic diversity and distribution dynamics of multidrug-resistant Mycobacterium tuberculosis isolates in Nepal

Multidrug-resistant tuberculosis (MDR-TB) is an emerging public health problem in Nepal. Despite the implementation of a successful TB control program in Nepal, notifications of MDR-TB are increasing, yet the reasons are unknown. The objective of this study was to understand the genetic diversity and epidemiological characteristics of MDR-Mycobacterium tuberculosis (MTB) isolates in Nepal. We isolated and genotyped 498 MDR-MTB isolates collected from April 2009 to March 2013 and analyzed the patients' background information. Our results showed that the lineage 2 (Beijing family) was the most predominant lineage (n = 241; 48.4%), followed by lineage 3 (n = 153, 30.7%). Lineage 4 was the third most prevalent (n = 73, 14.5%) followed by lineage 1 (n = 32, 6.4%). The lineages were significantly associated with geographic region, ethnic group, age and sex of patients. The Beijing genotype was found to have an important role in transmitting MDR-TB in Nepal and was significantly associated with the eastern region, mongoloid ethnic group and younger age group. We conclude that early diagnosis and treatment including molecular-epidemiological surveillance of MDR-TB cases will help to control transmission of MDR-TB in Nepal.

Viability, biofilm formation, and MazEF expression in drug-sensitive and drug-resistant Mycobacterium tuberculosis strains circulating in Xinjiang, China

Background

Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is one of the most common chronic infectious amphixenotic diseases worldwide. Prevention and control of TB are greatly difficult, due to the increase in drug-resistant TB, particularly multidrug-resistant TB. We speculated that there were some differences between drug-sensitive and drug-resistant MTB strains and that mazEF3,6,9 toxin–antitoxin systems (TASs) were involved in MTB viability. This study aimed to investigate differences in viability, biofilm formation, and MazEF expression between drug-sensitive and drug-resistant MTB strains circulating in Xinjiang, China, and whether mazEF3,6,9 TASs contribute to MTB viability under stress conditions.

Materials and methods

Growth profiles and biofilm-formation abilities of drug-sensitive, drug-resistant MTB strains and the control strain H37Rv were monitored. Using molecular biology experiments, the mRNA expression of the mazF3, 6, and 9 toxin genes, the mazE3, 6, and 9 antitoxin genes, and expression of the MazF9 protein were detected in the different MTB strains, H37RvΔmazEF3,6,9 mutants from the H37Rv parent strain were generated, and mutant viability was tested.

Results

Ex vivo culture analyses demonstrated that drug-resistant MTB strains exhibit higher survival rates than drug-sensitive strains and the control strain H37Rv. However, there was no statistical difference in biofilm-formation ability in the drug-sensitive, drug-resistant, and H37Rv strains. mazE3,6 mRNA-expression levels were relatively reduced in the drug-sensitive and drug-resistant strains compared to H37Rv. Conversely, mazE3,9 expression was increased in drug-sensitive strains compared to drug-resistant strains. Furthermore, compared with the H37Rv strain, mazF3,6 expression was increased in drug-resistant strains, mazF9 expression was increased in drug-sensitive strains, and mazF9 exhibited reduced expression in drug-resistant strains compared with drug-sensitive strains. Protein expression of mazF9 was increased in drug-sensitive and drug-resistant strains compared to H37Rv, while drug-resistant strains exhibited reduced mazF9 expression compared to drug-sensitive strains. Compared to H37Rv, H37RvΔmazEF3,6,9-deletion mutants grew more slowly under both stress conditions, and their ability to survive in host macrophages was also weaker. Furthermore, the host macrophage-apoptosis rate was higher after infection with any of the H37RvΔmazEF3,6,9 mutants than with the H37Rv strain.

Conclusion

The increased viability of MTB drug-resistant strains compared with drug-sensitive strains is likely to be related to differential MazEF mRNA and protein expression. mazEF3,6,9 TASs contribute to MTB viability under stress conditions.

Mcl-1 signals pathway inhibitors in mouse peritoneal macrophage apoptosis infected with the Xinjiang strain of M. tuberculosis

A present, myeloid cell leukemia-1 (Mcl-1) was suggested as a potential new target for controlling latent TB infection. Therefore, we investigated the role of the Mcl-1 signalling pathway in mouse peritoneal macrophages infected with XJ-MTB, aiming at finding a new strategy for TB management in Xinjiang. We using TUNEL, Immunohistochemical analysis, ELISA, HE, RT-PCR and Western blot detected macrophages apoptosis, the damage of mice tissues and the expression of apoptosis genes and proteins. Results found that inhibition of the Mcl-1 signalling pathway not only reduced the survival of intracellular XJ-MTB, but also increased peritoneal macrophage apoptosis in latent XJ-MTB-infected mouse peritoneal macrophages and relieved the pathological damage of mouse organs infected with XJ-MTB, especially MAPK signalling pathway inhibitor PD98059 (P<0.05). Moreover, after inhibitor PD98059 treated mouse peritoneal macrophages infected with XJ-MTB, Bcl-2, Bax and Mcl-1 were reduced, while Cytochrome-c and Caspase-8 protein levels were significantly increased, and Cytochrome-c protein levels was significant higher than Caspase-8 (P<0.05). In conclusion, the MAPK signalling pathway inhibitor PD98059 down-regulated Mcl-1 expression and effectively increased macrophage apoptosis in mice infected with XJ-MTB. Furthermore, it also relief pathological organ damage and promote the elimination of inflammation. The intrinsic apoptotic pathway plays a predominant role in the regulatory role.

The study on the association between Beijing genotype family and drug susceptibility phenotypes of Mycobacterium tuberculosis in Beijing

The predominant prevalent Mycobacterium tuberculosis (M. tb) lineage was the Beijing genotype family in Beijing. There has been no systematic study on the association between drug resistance and Beijing genotype. Here we collected 268 M. tb strains, analyzed the background information and the bacteriological characteristics. The mean age of the cases was 40.12 years; male patients were almost three times than female patients. After genotyping analyzation, 81.7% (219/268) strains were categorized as Beijing genotype; no significant difference was observed between Beijing and non-Beijing genotype in gender, age and treatment history. Drug susceptibility testing (DST) analyzation demonstrated that 172 (64.2%) strains were fully sensitive to all drugs (Isoniazid, Rifampin, Streptomycin, and Ethambutol), while 96 (35.8%) strains were resistant to at least one of the drugs. Beijing genotype strains exhibited a significantly higher clustering rate. However, no significant association relationship was observed between drug resistance and Beijing genotype family. The study provided insights into the genotype diversity and revealed that the frequencies of drug-resistance of Beijing genotype strains.It would be helpful for the establishment of the efficient tuberculosis (TB) prevention and control strategy in Beijing.

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.

A First Insight into the Genetic Diversity and Drug Susceptibility Pattern of Mycobacterium tuberculosis Complex in Zhejiang, China

In this study, our aim was to determine the predominant genotypes among the Mycobacterium tuberculosis (MTB) strains circulating in Zhejiang Province. In addition, we also sought to determine the potential associations between MTB genotypes and susceptibility to first-line drugs. Out of these isolates, 673 (71.6%) were classified into the Beijing genotype, while the other 267 (28.4%) were from non-Beijing families. The highest proportion of Beijing genotype was found in Huzhou (80.0%) and the lowest in Lishui (48.3%). Statistical analysis revealed that there was a significant difference in the prevalence of Beijing genotype among different regions (χ² = 17.57, P = 0.04). In addition, the overall proportions of drug resistance to INH, RIF, SM, and EMB were 13.2% (124/940), 21.8% (75/940), 3.4% (32/940), and 5.9% (55/940) in Zhejiang, respectively. Further comparison revealed that there was no significant difference in drug susceptibility profiles between Beijing and non-Beijing strains (P > 0.05). In conclusion, we describe the genetic diversity and drug susceptibility pattern of MTB in Zhejiang for the first time. Our data demonstrate that Beijing genotype is the predominant lineage in Zhejiang, while the distribution of Beijing-genotype strains shows geographic diversity. In addition, no correlation is observed between Beijing genotype and anti-TB drug resistance.

Pediatric Extrapulmonary Tuberculosis: Clinical Spectrum, Risk Factors and Diagnostic Challenges in a Low Prevalence Region

BACKGROUND

Children are at higher risk of tuberculosis (TB) dissemination and extrapulmonary disease, contributing greatly to TB-associated morbidity and long-term sequelae. However, there are very few studies that assess the impact and clinical spectrum of pediatric extrapulmonary TB (EPTB) in low-prevalence regions.

METHODS

Children <18 years of age diagnosed with TB in Madrid region (2005-2013) were reviewed. We compared the epidemiology, clinical characteristics and the performance of diagnostic tests in childhood extrapulmonary and pulmonary disease. We performed a multivariate logistic regression to identify factors associated with EPTB.

RESULTS

During the study period, 93 of 526 pediatric TB cases had EPTB (17.7%). The most common site was lymphatic TB (34.5%). The source case was not identified in most extrapulmonary cases, contrary to pulmonary TB (28% vs. 63.3%; P < 0.001). The tuberculin-skin-test induration was smaller in EPTB cases (<5 mm 22% vs. 5%; P < 0.001), but the sensitivity of interferon-gamma-release-assays was similar (76.9% vs. 79.4%). Children with EPTB presented higher rate of bacteriologic confirmation (66% vs. 49.4%; P < 0.01), and higher incidence of multidrug resistant TB (8.2% vs. 1.6%; P = 0.03). Complications were present in 40.2% extrapulmonary cases. EPTB was associated with the child's foreign origin [odds ratio (OR) 2.3 (1.1-5.3)], immune disorders [OR 5.8 (1.9-17.1)] and drug resistance [OR 2.4 (1.1-5.4)].

CONCLUSIONS

In our low-prevalence region, childhood EPTB was linked to immigrant status, immune disorders and drug resistance, and presented high rate of complications. Our study underscores the relevance of improved diagnostic tools and systematic TB screening in high risk populations.

Multicenter Study of the Emergence and Genetic Characteristics of Pyrazinamide-Resistant Tuberculosis in China

The aim of this study was to investigate the epidemiology of pyrazinamide (PZA) resistance and the associated risk factors as well as to evaluate the pncA gene loci as a marker for PZA resistance in China. A population-based multicenter study of pulmonary tuberculosis (TB) cases was carried out from 2011 to 2013 in four Chinese districts/counties with different geographic and socioeconomic features. Testing for multidrug-resistant tuberculosis (MDR-TB) and susceptibility to PZA was done by the proportion method on Lowenstein-Jensen medium and Bactec MGIT 960, respectively. Mutations in the pncA gene were identified by sequencing. Among 878 culture-positive cases, 147 (16.7%) were resistant to PZA, with a significantly higher proportion among MDR isolates than among the first-line drug-susceptible isolates (30.2% versus 7.7%; P < 0.001). In total, 136 isolates had a nonsynonymous pncA mutation, with a comparable diagnostic performance between Beijing family and non-Beijing family as well as between MDR-TB and first-line drug-susceptible TB. Furthermore, the mutations in isolates with high-level PZA resistance (MIC > 500 mg/liter) were observed mainly in three regions of the pncA gene (codons 51 to 76, codons 130 to 142, and codons 163 to 180). Patients with prior treatment history had a significantly higher risk for PZA monoresistance (odds ratio [OR], 2.86; 95% confidence interval [CI], 1.363 to 6.015) and MDR PZA resistance (OR, 6.47; 95% CI, 3.186 to 13.15), while the additional factors associated with MDR PZA resistance were the patient's age (OR, 1.02; 95% CI, 1.003 to 1.042), lung cavity (OR, 2.64; 95% CI, 1.296 to 5.391). These findings suggest that it is a priority to identify PZA resistance in MDR-TB and that a rapid molecular diagnostic test based on pncA mutations in the Chinese settings where MDR-TB prevalence is high should be developed.

Drug-resistant tuberculosis viewed from bacterial and host genomes

The outcome of infection with Mycobacterium tuberculosis (MTB) is largely influenced by the host-pathogen interaction in which both the human host and the MTB genetic backgrounds play an important role. Whether this interaction also influences the selection and expansion of drug-resistant MTB strains is the primary focus of this review. We first outline the main and recent findings regarding MTB determinants implicated in the development of drug resistance. Second, we examine data regarding human genetic factors that may play a role in TB drug resistance. We highlight interesting openings for TB research and therapy.

Detection and characterization of drug-resistant conferring genes in Mycobacterium tuberculosis complex strains: A prospective study in two distant regions of Ghana

We spoligotyped and screened 1490 clinical Mycobacterium tuberculosis complex strains from Northern and Greater Accra regions of Ghana against INH and RIF using the microplate alamar blue phenotypic assay. Specific drug resistance associated genetic elements of drug resistant strains were analyzed for mutations. A total of 111 (7.5%), 10 (0.7%) and 40 (2.6%) were mono-resistant to INH, RIF, and MDR, respectively. We found the Ghana spoligotype to be associated with drug resistance (INH: 22.1%; p = 0.0000, RIF: 6.2%; p = 0.0103, MDR: 4.6%; p = 0.0240) as compared to the Cameroon spoligotype (INH: 6.7%, RIF: 2.4%, MDR: 1.6%). The propensity for an isolate to harbour katG S315T mutation was higher in M. tuberculosis (75.8%) than Mycobacterium africanum (51.7%) (p = 0.0000) whereas the opposite was true for inhApro mutations; MAF (48.3%) compared to MTBSS (26.7%) (p = 0.0419). We identified possible novel compensatory INH resistance mutations in inhA (G204D) and ahpCpro (-88G/A and -142G/A) and a novel ndh mutation K32R. We detected two possible rpoC mutations (G332R and V483G), which occurred independently with rpoB S450L, respectively. The study provides the first evidence that associate the Ghana spoligotype with DR-TB and calls for further genome analyses for proper classification of this spoligotype and to explore for fitness implications and mechanisms underlying this observation.

Registration and management of community patients with tuberculosis in north-west China

OBJECTIVES

To describe the registration, management and characteristics of patients with tuberculosis (TB) in north-west China, and investigate whether patients with TB were diagnosed and treated in a timely manner.

STUDY DESIGN

Health-facility-based retrospective data were collected from district patient registers and case reports for all patients with TB registered from January 2009 to December 2011 in Xinjiang Uygur Autonomous Region, north-west China.

METHODS

Patient characteristics and clinical data were collected from the national TB epidemic reporting system using standardized case reporting forms for diagnosis, treatment and outcome. Data were collected and entered by trained health staff in the regional TB clinics.

RESULTS

In total, data for 20,396 patients with TB were collected; of these, 78.5% were farmers. The age peaks were 20-44 years and 60-74 years. Average health-seeking and diagnostic delays were 32 days and two days, respectively. More than half (54.7%) of the patients with smear-negative TB were diagnosed by chest x-ray. Moreover, 94.3% of patients with TB were treated successfully. From 2009 to 2011, the health-seeking delay decreased significantly (P < 0.05), and the diagnostic delay increased significantly (P < 0.05). A significant decreasing trend in smear-positive TB was observed (P < 0.05), along with an increasing trend in treatment success (P < 0.05).

CONCLUSIONS

In north-west China, there is a need to focus on key high-risk populations for prevention and control of TB, such as those aged 20-44 years and 60-74 years, males and farmers. Delays in diagnosis and treatment have a negative effect on cure rates and make it more difficult to control the propagation of TB.

Correlations between drug resistance of Beijing/W lineage clinical isolates of Mycobacterium tuberculosis and sublineages: a 2009-2013 prospective study in Xinjiang province, China

BACKGROUND

The prevalence of drug-resistant tuberculosis (TB) in Xinjiang is higher than in other regions of China, and Beijing/W lineage Mycobacterium tuberculosis (MTB) is the dominant strain of MTB in Xinjiang. However, information on multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB, particularly the correlation between MDR and the Beijing/W lineage and the correlation between drug resistance and the Beijing/W sublineage strains, is limited.

MATERIAL/METHODS

We conducted a prospective study to describe the prevalence of MDR/XDR TB, Beijing/W lineage and sublineage strains in Xinjiang in China from 2009 to 2013. All MTB underwent drug susceptibility testing to the first- and second-line anti-tuberculosis drugs. The Beijing/W lineages and sublineages were detected by large-sequence polymorphisms with polymerase chain reaction.

RESULTS

A total of 410 clinical isolates were identified. The overall percentage of MDR and XDR cases in Xinjiang was 13.2% (54/410) and 13.0% (7/54), respectively. Overall, 9.8% (14/143) of the Beijing lineage MTB were MDR patients, and 15.6% (40/257) of the Non-Beijing lineage MTB were MDR patients. In the 143 Beijing MTB lineages, 11.2% isolates were in sublineage 105, 15.4% isolates were in sublineage 207, 69.2% isolates were in sublineage 181, and 4.2% isolates were in sublineage 150. None of the isolates were detected in sublineage 142. Significant differences between the Beijing/W and non-Beijing/W strains were observed regarding INH and EMB resistance, respectively.

CONCLUSIONS

The prevalence of the MDR TB in Xinjiang remains high and imposes challenges for TB control. Four Beijing/W sublineage isolates were observed in Xinjiang. There was no correlation between MDR and the Beijing/W lineage and no correlation between drug resistance and the Beijing/W sublineage strains. Surveillance of the clinical isolates of MTB is recommended to strengthen the identification of MDR/XDR TB and sublineages of the Beijing/W strains.