scholarly journals Programmable Base Editing in Mycobacterium tuberculosis Using an Engineered CRISPR RNA-Guided Cytidine Deaminase

2021 ◽  
Vol 3 ◽  
Author(s):  
Xin-Yuan Ding ◽  
Si-Shang Li ◽  
Yi-Man Geng ◽  
Mei-Yi Yan ◽  
Guo-Bao Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Molecular Mechanisms ◽  
Cytidine Deaminase ◽  
Point Mutations ◽  
Treatment Strategies ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Bacterial Physiology ◽  
Base Editing

Multidrug-resistant Mycobacterium tuberculosis (Mtb) infection seriously endangers global human health, creating an urgent need for new treatment strategies. Efficient genome editing tools can facilitate identification of key genes and pathways involved in bacterial physiology, pathogenesis, and drug resistance mechanisms, and thus contribute to the development of novel treatments for drug-resistant tuberculosis. Here, we report a two-plasmid system, MtbCBE, used to inactivate genes and introduce point mutations in Mtb. In this system, the assistant plasmid pRecX-NucSE107A expresses RecX and NucSE107A to repress RecA-dependent and NucS-dependent DNA repair systems, and the base editor plasmid pCBE expresses a fusion protein combining cytidine deaminase APOBEC1, Cas9 nickase (nCas9), and uracil DNA glycosylase inhibitor (UGI). Together, the two plasmids enabled efficient G:C to A:T base pair conversion at desired sites in the Mtb genome. The successful development of a base editing system will facilitate elucidation of the molecular mechanisms underlying Mtb pathogenesis and drug resistance and provide critical inspiration for the development of base editing tools in other microbes.

scholarly journals Antibiotic Resistance Profiles, Molecular Mechanisms and Innovative Treatment Strategies of Acinetobacter baumannii

2020 ◽  
Vol 8 (6) ◽  
pp. 935 ◽  
Author(s):  
Corneliu Ovidiu Vrancianu ◽  
Irina Gheorghe ◽  
Ilda Barbu Czobor ◽  
Mariana Carmen Chifiriuc
Keyword(s):  
Antibiotic Resistance ◽  
Acinetobacter Baumannii ◽  
Molecular Mechanisms ◽  
Treatment Strategies ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Negative Bacterium ◽  
Innovative Strategies ◽  
Industry Environment ◽  
Underlying Mechanisms

Antibiotic resistance is one of the biggest challenges for the clinical sector and industry, environment and societal development. One of the most important pathogens responsible for severe nosocomial infections is Acinetobacter baumannii, a Gram-negative bacterium from the Moraxellaceae family, due to its various resistance mechanisms, such as the β-lactamases production, efflux pumps, decreased membrane permeability and altered target site of the antibiotic. The enormous adaptive capacity of A. baumannii and the acquisition and transfer of antibiotic resistance determinants contribute to the ineffectiveness of most current therapeutic strategies, including last-line or combined antibiotic therapy. In this review, we will present an update of the antibiotic resistance profiles and underlying mechanisms in A. baumannii and the current progress in developing innovative strategies for combating multidrug-resistant A. baumannii (MDRAB) infections.

scholarly journals Drug Resistance Mechanisms in Tuberculosis

2020 ◽  
Author(s):  
Lanfranco Fattorini ◽  
Angelo Iacobino ◽  
Federico Giannoni
Keyword(s):  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Drug Distribution ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Diagnostic Methods ◽  
Drug Resistant ◽  
Resistance Development ◽  
Intrinsic Drug Resistance ◽  
Incident Cases

The increased incidence of multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) strains, defined as resistant to at least isoniazid and rifampin, the two highly bactericidal first-line drugs, is a major concern for tuberculosis (TB) control. The worldwide estimate of almost half a million incident cases of MDR/rifampin-resistant TB, is causing increasing concern. In this view, it is important to continuously update the knowledge on the mechanisms involved in the development of drug-resistant TB. Clinical, biological and microbiological reasons account for the generation of resistance, including: (i) nonadherence of patients to their therapy, and/or errors of physicians in therapy management, (ii) complexity and poor vascularization of granulomatous lesions, which obstruct drug distribution to some sites, resulting in resistance development, (iii) intrinsic drug resistance of tubercle bacilli, (iv) formation of non-replicating, drug-tolerant bacilli inside the granulomas, (v) development of mutations in Mtb genes, which are the most important molecular mechanisms of resistance. Here, a piece of information on the interplay of these factors is provided, to facilitate the clinical and microbiological management of drug-resistant TB at the global level, with attention also to the most recent diagnostic methods.

Genotypic analysis of multidrug-resistant Mycobacterium tuberculosis isolates from Monterrey, Mexico

2004 ◽  
Vol 53 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Srinivas V. Ramaswamy ◽  
Shu-Jun Dou ◽  
Adrian Rendon ◽  
Zhenhua Yang ◽  
M. Donald Cave ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Secondary Resistance ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Genotypic Analysis ◽  
Mdr Tb

Thirty-seven multidrug-resistant and 13 pan-susceptible isolates of Mycobacterium tuberculosis were analysed for the diversity of genotypes associated with known drug-resistance mechanisms. The isolates were obtained from patients attending a university tuberculosis clinic in Monterrey, Mexico. A total of 25 IS6110-RFLP patterns were obtained from the multidrug-resistant tuberculosis (MDR-TB) isolates. Approximately 65 % of the MDR-TB isolates were attributed to secondary resistance. Different drug-susceptibility patterns were seen with the clustered isolates. The percentage of isolates resistant to isoniazid (INH), rifampicin (RIF), ethambutol (EMB) and streptomycin (STR) was 100, 97.3, 48.7 and 67.6, respectively. The most common resistance-associated polymorphisms for the four drugs were as follows: INH, Ser315Thr (67.6 %) in katG; RIF, Ser450Leu (41.7 %) in rpoB; EMB, Met306Ile/Val/Leu (66.7 %) in embB; and STR, Lys43Arg (24 %) in rpsL. Drug-resistance-associated mutations were similar to changes occurring in isolates from other areas of the world, but unique, previously unreported, mutations in katG (n = 5), rpoB (n = 1) and rrs (n = 3) were also identified.

scholarly journals Rates and Mechanisms of Resistance Development in Mycobacterium tuberculosis to a Novel Diarylquinoline ATP Synthase Inhibitor

2009 ◽  
Vol 54 (3) ◽  
pp. 1022-1028 ◽  
Author(s):  
E. Huitric ◽  
P. Verhasselt ◽  
A. Koul ◽  
K. Andries ◽  
S. Hoffner ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Atp Synthase ◽  
Point Mutations ◽  
Antimycobacterial Activity ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Investigational Drug ◽  
Resistant Mutants ◽  
Synthase Inhibitor

ABSTRACT R207910 (also known as TMC207) is an investigational drug currently in clinical studies for the treatment of multidrug-resistant (MDR) tuberculosis. It has a high degree of antimycobacterial activity and is equally effective against drug-susceptible and MDR Mycobacterium tuberculosis isolates. In the present study, we characterized the development of resistance to R207910 in vitro. Ninety-seven independent R207910-resistant mutants were selected from seven different clinical isolates of M. tuberculosis (three drug-susceptible and four MDR isolates) at 10×, 30×, and 100× the MIC. At a concentration of 0.3 mg/liter (10× the MIC), the mutation rates ranged from 4.7 × 10−7 to 8.9 × 10−9 mutations per cell per division, and at 1.0 mg/liter (30× the MIC) the mutation rate ranged from 3.9 × 10−8 to 2.4 × 10−9. No resistant mutants were obtained at 3 mg/liter (100× the MIC). The level of resistance ranged from 0.12 to 3.84 mg/liter for the mutants identified; these concentrations represent 4- to 128-fold increases in the MICs. For 53 of the resistant mutants, the atpE gene, which encodes a transmembrane and oligomeric C subunit of the ATP synthase and which was previously shown to be involved in resistance, was sequenced. For 15/53 mutants, five different point mutations resulting in five different amino acid substitutions were identified in the atpE gene. For 38/53 mutants, no atpE mutations were found and sequencing of the complete F0 ATP synthase operon (atpB, atpE, and atpF genes) and the F1 ATP synthase operon (atpH, atpA, atpG, atpD, and atpC genes) from three mutants revealed no mutations, indicating other, alternative resistance mechanisms. Competition assays showed no measurable reduction in the fitness of the mutants compared to that of the isogenic wild types.

scholarly journals Analysis of drug resistance and mutation profiles in Mycobacterium tuberculosis isolates in a surveillance site in Beijing, China

2021 ◽  
Vol 49 (1) ◽  
pp. 030006052098493
Author(s):  
Jie Zhang ◽  
Yixuan Ren ◽  
Liping Pan ◽  
Junli Yi ◽  
Tong Guan ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Drug Testing ◽  
Multidrug Resistant ◽  
High Rate ◽  
Drug Resistant ◽  
Surveillance Site ◽  
Mdr Tb ◽  
Previously Treated Patients ◽  
Beijing China

Objective This study analyzed drug resistance and mutations profiles in Mycobacterium tuberculosis isolates in a surveillance site in Huairou District, Beijing, China. Methods The proportion method was used to assess drug resistance profiles for four first-line and seven second-line anti-tuberculosis (TB) drugs. Molecular line probe assays were used for the rapid detection of resistance to rifampicin (RIF) and isoniazid (INH). Results Among 235 strains of M. tuberculosis, 79 (33.6%) isolates were resistant to one or more drugs. The isolates included 18 monoresistant (7.7%), 19 polyresistant (8.1%), 28 RIF-resistant (11.9%), 24 multidrug-resistant (MDR) (10.2%), 7 pre-extensively drug-resistant (XDR, 3.0%), and 2 XDR strains (0.9%). A higher rate of MDR-TB was detected among previously treated patients than among patients with newly diagnosed TB (34.5% vs. 6.8%). The majority (62.5%) of RIF-resistant isolates exhibited a mutation at S531L in the DNA-dependent RNA polymerase gene. Meanwhile, 62.9% of INH-resistant isolates carried a mutation at S315T1 in the katG gene. Conclusion Our results confirmed the high rate of drug-resistant TB, especially MDR-TB, in Huairou District, Beijing, China. Therefore, detailed drug testing is crucial in the evaluation of MDR-TB treatment.

scholarly journals Genomic Variations in Drug Resistant Mycobacterium tuberculosis Strains Collected from Patients with Different Localization of Infection

Antibiotics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Ekaterina Chernyaeva ◽  
Mikhail Rotkevich ◽  
Ksenia Krasheninnikova ◽  
Alla Lapidus ◽  
Dmitrii E. Polev ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Pulmonary Tuberculosis ◽  
Central Asia ◽  
Phylogenetic Analyses ◽  
Treatment Success ◽  
Point Mutations ◽  
Whole Genome Sequence ◽  
Public Health Importance ◽  
Resistance Patterns

Mycobacterium tuberculosis is a highly studied pathogen due to public health importance. Despite this, problems like early drug resistance, diagnostics and treatment success prediction are still not fully resolved. Here, we analyze the incidence of point mutations widely used for drug resistance detection in laboratory practice and conduct comparative analysis of whole-genome sequence (WGS) for clinical M. tuberculosis strains collected from patients with pulmonary tuberculosis (PTB) and extra-pulmonary tuberculosis (XPTB) localization. A total of 72 pulmonary and 73 extrapulmonary microbiologically characterized M. tuberculosis isolates were collected from patients from 2007 to 2014 in Russia. Genomic DNA was used for WGS and obtained data allowed identifying major mutations known to be associated with drug resistance to first-line and second-line antituberculous drugs. In some cases previously described mutations were not identified. Using genome-based phylogenetic analysis we identified M. tuberculosis substrains associated with distinctions in the occurrence in PTB vs. XPTB cases. Phylogenetic analyses did reveal M. tuberculosis genetic substrains associated with TB localization. XPTB was associated with Beijing sublineages Central Asia (Beijing CAO), Central Asia Clade A (Beijing A) and 4.8 groups, while PTB localization was associated with group LAM (4.3). Further, the XPTB strain in some cases showed elevated drug resistance patterns relative to PTB isolates. HIV was significantly associated with the development of XPTB in the Beijing B0/W148 group and among unclustered Beijing isolates.

scholarly journals Increasing prevalence of resistance to second-line drugs among multidrug-resistant Mycobacterium tuberculosis isolates in Kuwait

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noura M. Al-Mutairi ◽  
Suhail Ahmad ◽  
Eiman Mokaddas
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Mutation Detection ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Genetic Mutations ◽  
Second Line ◽  
Injectable Drugs ◽  
Mdr Tb ◽  
Phenotypic Susceptibility

AbstractMolecular methods detect genetic mutations associated with drug resistance. This study detected resistance-conferring mutations in gyrA/gyrB for fluoroquinolones and rrs/eis genes for second-line injectable drugs (SLIDs) among multidrug-resistant Mycobacterium tuberculosis (MDR-TB) isolates in Kuwait. Fifty pansusceptible M. tuberculosis and 102 MDR-TB strains were tested. Phenotypic susceptibility testing was performed by MGIT 960 system using SIRE drug kit. GenoType MTBDRsl version 1 (gMTBDRslv1) and GenoType MTBDRsl version 2 (gMTBDRslv2) tests were used for mutation detection. Results were validated by PCR-sequencing of respective genes. Fingerprinting was performed by spoligotyping. No mutations were detected in pansusceptible isolates. gMTBDRslv1 detected gyrA mutations in 12 and rrs mutations in 8 MDR-TB isolates. gMTBDRsl2 additionally detected gyrB mutations in 2 and eis mutation in 1 isolate. Mutations in both gyrA/gyrB and rrs/eis were not detected. gMTBDRslv1 also detected ethambutol resistance-conferring embB mutations in 59 isolates. Although XDR-TB was not detected, frequency of resistance-conferring mutations for fluoroquinolones or SLIDs was significantly higher among isolates collected during 2013–2019 versus 2006–2012. Application of both tests is warranted for proper management of MDR-TB patients in Kuwait as gMTBDRslv2 detected resistance to fluoroquinolones and/or SLIDs in 3 additional isolates while gMTBDRslv1 additionally detected resistance to ethambutol in 58% of MDR-TB isolates.

Exploring the Contribution of Mycobacteria Characteristics in Their Interaction with Human Macrophages

2013 ◽  
Vol 19 (5) ◽  
pp. 1159-1169 ◽  
Author(s):  
Carla Silva ◽  
Joao Perdigao ◽  
Elsa Alverca ◽  
António P. Alves de Matos ◽  
Patricia A. Carvalho ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Envelope ◽  
Treatment Strategies ◽  
Human Monocyte ◽  
Selective Advantage ◽  
Multidrug Resistant ◽  
Structural Features ◽  
Major Health Problem ◽  
Transmission Electron ◽  
Mdr Tb

AbstractTuberculosis (TB) is a major health problem. The emergence of multidrug resistant (MDR)Mycobacterium tuberculosis(Mtb) isolates confounds treatment strategies. In Portugal, cases of MDR-TB are reported annually with an increased incidence noted in Lisbon. The majority of these MDR-TB cases are due to closely related mycobacteria known collectively as theLisboafamily and Q1 cluster. Genetic determinants linked to drug resistance have been exhaustively studied resulting in the identification of family and cluster specific mutations. Nevertheless, little is known about other factors involved in development of mycobacteria drug resistance. Here, we complement genetic analysis with the study of morphological and structural features of theLisboafamily and Q1 cluster isolates by using scanning and transmission electron microscopy. This analysis allowed the identification of structural differences, such as cell envelope thickness, between Mtb clinical isolates that are correlated with antibiotic resistance. The infection of human monocyte derived macrophages allowed us to document the relative selective advantage of theLisboafamily isolates over other circulating Mtb isolates.

scholarly journals Genotypes of Mycobacterium tuberculosis isolates circulating in Shaanxi Province, China

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242971
Author(s):  
Yan Li ◽  
Yu Pang ◽  
Tianhua Zhang ◽  
Xiaoping Xian ◽  
Jian Yang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Multidrug Resistant ◽  
Shaanxi Province ◽  
Drug Resistant ◽  
Beijing Family ◽  
Tuberculosis Patients ◽  
Smear Positive Pulmonary Tuberculosis ◽  
Discriminatory Index

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.

scholarly journals Constraints of Drug Resistance in Mycobacterium tuberculosis - Prospects for Pharmacological Reversion of Susceptibility to Antibiotics

2017 ◽  
Vol 8 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Aleksandr I. Ilin ◽  
Murat E. Kulmanov ◽  
Ilya S. Korotetskiy ◽  
Marina V. Lankina ◽  
Gulshara K. Akhmetova ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Genetic Heterogeneity ◽  
Multidrug Resistant ◽  
Resistance Mutations ◽  
General Increase ◽  
Drug Induced ◽  
Mdr Tb ◽  
Resistant Strains

Emergence of multidrug resistant strains ofMycobacterium tuberculosis(MDR-TB) threatens humanity. This problem was complicated by the crisis in development of new anti-tuberculosis antibiotics. Induced reversion of drug resistance seems promising to overcome the problem. Successful clinical trial of a new anti-tuberculosis nanomolecular complex FS-1 has demonstrated prospectively of this approach in combating MDR-TB. Several clinical MDR-TB cultures were isolated from sputum samples prior and in the process of the clinical trial. Every isolate was tested for susceptibility to antibiotics and then they were sequenced for comparative genomics. It was found that the treatment with FS-1 caused an increase in the number of antibiotic susceptible strains among Mtb isolates that was associated with a general increase of genetic heterogeneity of the isolates. Observed impairing of phthiocerol dimycocerosate biosynthesis by disruptive mutations inppsACDsubunits indicated a possible virulence remission for the sake of persistence. It was hypothesized that the FS-1 treatment eradicated the most drug resistant Mtb variants from the population by aggravating the fitness cost of drug resistance mutations. Analysis of distribution of these mutations in the global Mtb population revealed that many of them were incompatible with each other and dependent on allelic states of many other polymorphic loci. The latter discovery may explain the negative correlation between the genetic heterogeneity of the population and the level of drug tolerance. To the best of our knowledge, this work was the first experimental confirmation of the drug induced antibiotic resistance reversion by the induced synergy mechanism that previously was predicted theoretically.

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