Molecular Characterization of Drug-Resistant Beijing Family Isolates of Mycobacterium Tuberculosis from Tianjin, China

Li, Guilian; Zhao, De-fu; Xie, Tong; Ju, Hanfang; Mu, Cheng; Wang, Xiexiu

doi:10.1016/s0895-3988(10)60051-7

Cited by 14 publications

(21 citation statements)

References 41 publications

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“…However, some reports have indicated that only less than 35% of EMB-resistant M. tuberculosis isolates harbored mutations in the embB codon 306 [23,24]. Bahrami et al found that 29% (14/48) of the EMB-resistant isolates from Iran had a mutation at emb306 codon determined by a multiplex allele-specific PCR method [25].…”

Section: Discussionmentioning

confidence: 99%

Frequency of mutational changes in the embB among the ethambutol-resistant strains of Mycobacterium tuberculosis in Iran

Rezaei

Haeili

Mohajeri

et al. 2016

J Infect Dev Ctries

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Introduction: Early detection of drug resistant tuberculosis is one of the main priorities of TB control program. Ethambutol (EMB) is a firstline anti-TB drug that is effective for preventing treatment failures caused by Mycobacterium tuberculosis strains that are resistant to other drugs. The aim of this study was to sequence the embB gene to characterize the mutations causing resistance to EMB and to analyze the relationship between bacterial genotype and EMB resistance among M. tuberculosis isolates in Iran. Methodology: A total of 20 M. tuberculosis isolates comprising 10 multidrug-resistant (MDR) and 10 non-MDR isolates, recovered from TB patients in four regions: Tehran, Isfahan, Zahedan, Khorasan, were analyzed. Mutational profiling was performed by amplifying and sequencing the embB gene. Spoligotyping was carried out to characterize the bacterial genotype. Results: Phenotypic EMB resistance was found in 13 strains. Mutations affecting ethambutol resistance-determining region (ERDR) of the embB were identified in 6 of 13 EMB-resistant isolates. The majority of these mutations resulted in amino acid substitution at position 306 (M306V). A novel mutation at codon 366 was identified (S366L) in one isolate. Ural was the most predominant genotype in the studied population. Beijing genotype was associated with both MDR and EMB resistance in which all mutations occurred at codon 306 of the embB gene. Conclusion: A significant association between Beijing genotype and EMB resistance was found, mainly due to mutations at embB306. Results of this study can be used as a basis to develop or improve rapid molecular tests to monitor drug-resistant strains in this country.

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Section: Discussionmentioning

confidence: 99%

Frequency of mutational changes in the embB among the ethambutol-resistant strains of Mycobacterium tuberculosis in Iran

Rezaei

Haeili

Mohajeri

et al. 2016

J Infect Dev Ctries

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“…All stored and new clinical isolates were tested for RIF susceptibility on L-J slants by the absolute concentration method. Isolates were determined to be resistant to RIF-at concentrations of either 50 g/ml (low-level resistance) or 250 g/ml (high-level resistance)-if the inoculum grew on one-quarter (1ϩ) of the slant surface or there were Ն20 colonies on slants containing the corresponding RIF concentrations, after 4 weeks incubation at 35 to 37°C (18).…”

Section: Fig 1 (A)mentioning

confidence: 99%

Rolling Circle Amplification for Direct Detection of rpoB Gene Mutations in Mycobacterium tuberculosis Isolates from Clinical Specimens

et al. 2014

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e Rapid and accurate detection of multidrug resistance (MDR) in Mycobacterium tuberculosis is essential to improve treatment outcomes and reduce global transmission but remains a challenge. Rifampin (RIF) resistance is a reliable marker of MDR tuberculosis (TB) since by far the majority of RIF-resistant strains are also isoniazid (INH) resistant. We have developed a rapid, sensitive, and specific method for detecting the most common mutations associated with RIF resistance, in the RIF resistance determining region (RRDR) of rpoB, using a cocktail of six padlock probes and rolling circle amplification (RCA). We used this method to test 46 stored M. tuberculosis clinical isolates with known RIF susceptibility profiles (18 RIF resistant, 28 susceptible), a standard susceptible strain (H37Rv, ATCC 27294) and 78 M. tuberculosis culture-positive clinical (sputum) samples, 59 of which grew RIF-resistant strains. All stored clinical isolates were correctly categorized, by the padlock probe/RCA method, as RIF susceptible or resistant; the sensitivity and specificity of the method, for direct detection of phenotypically RIF-resistant M. tuberculosis in clinical specimens, were 96.6 and 89.5%, respectively. This method is rapid, simple, and inexpensive and has the potential for high-throughput routine screening of clinical specimens for MDR M. tuberculosis, particularly in high prevalence settings with limited resources. With one-third of the world's population infected, tuberculosis (TB) is a major public health threat worldwide (1). The two most important drugs used to treat TB are isoniazid (INH) and rifampin (RIF). Inadequate or inappropriate therapy, together with long and costly treatment courses, often result in the emergence of drug resistance (2). Multidrug-resistant (MDR) Mycobacterium tuberculosis strains-defined as bacillary resistance to at least INH and RIF-have spread rapidly and become a global health emergency (3). Identification of these strains by drug susceptibility testing (DST) allows optimization of therapeutic efficacy and improved treatment outcomes while minimizing transmission of drug-resistant strains. However, phenotypic DST involving subculture is costly, it is too slow to guide optimal management of MDR-TB, and it lacks high-throughput capability. Commercial systems for rapid molecular identification of RIF resistance are available but expensive.RIF resistance in M. tuberculosis is associated with amino acid changes in the ␤-subunit of RNA polymerase, encoded by rpoB. The majority (90 to 95%) of mutations responsible for resistance are located in the 81-bp RIF resistance determining region (RRDR) of rpoB (4-6), and ca. 60 to 70% are found within two codons, 531 and 526. The fact that most mutations known to confer resistance are localized to a specific region facilitates the development of molecular methods for their detection. Sequencing and hybridization-based assays have been commonly used and can define the precise mutations involved (4, 7). Hybridization-based assays also provide a rapid...

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“…This may be expected given the overwhelming dominance of the Beijing family strain in most regions in China [17], [22]. In addition to its overall prevalence, Beijing family members are increasingly found associated with MDR-TB [23], [24] and enhanced transmissibility in some areas [25], [26].…”

Section: Discussionmentioning

confidence: 99%

Transmission Pattern of Drug-Resistant Tuberculosis and Its Implication for Tuberculosis Control in Eastern Rural China

Mathema

Jiang

et al. 2011

PLoS ONE

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ObjectiveTransmission 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.MethodsWe 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.ResultsOf 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.ConclusionTransmission 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.

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Molecular Characterization of Drug-Resistant Beijing Family Isolates of Mycobacterium Tuberculosis from Tianjin, China

Cited by 14 publications

References 41 publications

Frequency of mutational changes in the embB among the ethambutol-resistant strains of Mycobacterium tuberculosis in Iran

Frequency of mutational changes in the embB among the ethambutol-resistant strains of Mycobacterium tuberculosis in Iran

Rolling Circle Amplification for Direct Detection of rpoB Gene Mutations in Mycobacterium tuberculosis Isolates from Clinical Specimens

Transmission Pattern of Drug-Resistant Tuberculosis and Its Implication for Tuberculosis Control in Eastern Rural China

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