scholarly journals Activation of Antibiotic Production in Bacillus spp. by Cumulative Drug Resistance Mutations

2015 ◽  
Vol 59 (12) ◽  
pp. 7799-7804 ◽  
Author(s):  
Shigeo Tojo ◽  
Yukinori Tanaka ◽  
Kozo Ochi
Keyword(s):  
Drug Resistance ◽  
Antibiotic Production ◽  
Transcriptional Analysis ◽  
Peptide Antibiotics ◽  
Resistance Mutations ◽  
Content Type ◽  
Drug Resistance Mutations ◽  
Wide Range ◽  
Bacillus Spp ◽  
High Level

ABSTRACTBacillus subtilisstrains produce a wide range of antibiotics, including ribosomal and nonribosomal peptide antibiotics, as well as bacilysocin and neotrehalosadiamine. Mutations inB. subtilisstrain 168 that conferred resistance to drugs such as streptomycin and rifampin resulted in overproduction of the dipeptide antibiotic bacilysin. Cumulative drug resistance mutations, such as mutations in themthAandrpsLgenes, which confer low- and high-level resistance, respectively, to streptomycin, and mutations inrpoB, which confer resistance to rifampin, resulted in cells that overproduced bacilysin. Transcriptional analysis demonstrated that the enhanced transcription of biosynthesis genes was responsible for the overproduction of bacilysin. This approach was effective also in activating the cryptic genes ofBacillus amyloliquefaciens, leading to actual production of antibiotic(s).

scholarly journals Dramatic Activation of Antibiotic Production in Streptomyces coelicolor by Cumulative Drug Resistance Mutations

2008 ◽  
Vol 74 (9) ◽  
pp. 2834-2840 ◽  
Author(s):  
Guojun Wang ◽  
Takeshi Hosaka ◽  
Kozo Ochi
Keyword(s):  
Drug Resistance ◽  
Multiple Drug Resistance ◽  
Antibiotic Production ◽  
Streptomyces Coelicolor ◽  
Strain Improvement ◽  
Multiple Drug ◽  
Resistance Mutations ◽  
Drug Resistance Mutations ◽  
Order Of Magnitude

ABSTRACT We recently described a new method to activate antibiotic production in bacteria by introducing a mutation conferring resistance to a drug such as streptomycin, rifampin, paromomycin, or gentamicin. This method, however, enhanced antibiotic production by only up to an order of magnitude. Working with Streptomyces coelicolor A3(2), we established a method for the dramatic activation of antibiotic production by the sequential introduction of multiple drug resistance mutations. Septuple and octuple mutants, C7 and C8, thus obtained by screening for resistance to seven or eight drugs, produced huge amounts (1.63 g/liter) of the polyketide antibiotic actinorhodin, 180-fold higher than the level produced by the wild type. This dramatic overproduction was due to the acquisition of mutant ribosomes, with aberrant protein and ppGpp synthesis activity, as demonstrated by in vitro protein synthesis assays and by the abolition of antibiotic overproduction with relA disruption. This new approach, called “ribosome engineering,” requires less time, cost, and labor than other methods and may be widely utilized for bacterial strain improvement.

scholarly journals Combined Drug Resistance Mutations Substantially Enhance Enzyme Production inPaenibacillus agaridevorans

2018 ◽  
Vol 200 (17) ◽  
Author(s):  
Kazumi Funane ◽  
Yukinori Tanaka ◽  
Takeshi Hosaka ◽  
Kiriko Murakami ◽  
Takatsugu Miyazaki ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Enzyme Production ◽  
Scale Production ◽  
Wild Type ◽  
Resistance Mutations ◽  
Triple Mutant ◽  
Content Type ◽  
Wide Applicability ◽  
Drug Resistance Mutations ◽  
Industrial Enzyme

ABSTRACTThis study shows that sequential introduction of drug resistance mutations substantially increased enzyme production inPaenibacillus agaridevorans. The triple mutant YT478 (rsmGGln225→stop codon,rpsLK56R, andrpoBR485H), generated by screening for resistance to streptomycin and rifampin, expressed a 1,100-fold-larger amount of the extracellular enzyme cycloisomaltooligosaccharide glucanotransferase (CITase) than the wild-type strain. These mutants were characterized by higher intracellularS-adenosylmethionine concentrations during exponential phase and enhanced protein synthesis activity during stationary phase. Surprisingly, the maximal expression of CITase mRNA was similar in the wild-type and triple mutant strains, but the mutant showed greater CITase mRNA expression throughout the growth curve, resulting in enzyme overproduction. A metabolome analysis showed that the triple mutant YT478 had higher levels of nucleic acids and glycolysis metabolites than the wild type, indicating that YT478 mutant cells were activated. The production of CITase by the triple mutant was further enhanced by introducing a mutation conferring resistance to the rare earth element, scandium. This combined drug resistance mutation method also effectively enhanced the production of amylases, proteases, and agarases byP. agaridevoransandStreptomyces coelicolor. This method also activated the silent or weak expression of theP. agaridevoransCITase gene, as shown by comparisons of the CITase gene loci ofP. agaridevoransT-3040 and another cycloisomaltooligosaccharide-producing bacterium,Paenibacillussp. strain 598K. The simplicity and wide applicability of this method should facilitate not only industrial enzyme production but also the identification of dormant enzymes by activating the expression of silent or weakly expressed genes.IMPORTANCEEnzyme use has become more widespread in industry. This study evaluated the molecular basis and effectiveness of ribosome engineering in markedly enhancing enzyme production (>1,000-fold). This method, due to its simplicity, wide applicability, and scalability for large-scale production, should facilitate not only industrial enzyme production but also the identification of novel enzymes, because microorganisms contain many silent or weakly expressed genes which encode novel antibiotics or enzymes. Furthermore, this study provides a new mechanism for strain improvement, with a consistent rather than transient high expression of the key gene(s) involved in enzyme production.

scholarly journals Effect of Mutation and Genetic Background on Drug Resistance in Mycobacterium tuberculosis

2012 ◽  
Vol 56 (6) ◽  
pp. 3047-3053 ◽  
Author(s):  
Lukas Fenner ◽  
Matthias Egger ◽  
Thomas Bodmer ◽  
Ekkehardt Altpeter ◽  
Marcel Zwahlen ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Hot Spot ◽  
Multidrug Resistant ◽  
Beijing Genotype ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Content Type ◽  
Drug Resistance Mutations ◽  
Resistant Strains

ABSTRACTBacterial factors may contribute to the global emergence and spread of drug-resistant tuberculosis (TB). Only a few studies have reported on the interactions between different bacterial factors. We studied drug-resistantMycobacterium tuberculosisisolates from a nationwide study conducted from 2000 to 2008 in Switzerland. We determined quantitative drug resistance levels of first-line drugs by using Bactec MGIT-960 and drug resistance genotypes by sequencing the hot-spot regions of the relevant genes. We determined recent transmission by molecular methods and collected clinical data. Overall, we analyzed 158 isolates that were resistant to isoniazid, rifampin, or ethambutol, 48 (30.4%) of which were multidrug resistant. Among 154 isoniazid-resistant strains,katGmutations were associated with high-level andinhApromoter mutations with low-level drug resistance. OnlykatG(S315T) (65.6% of all isoniazid-resistant strains) andinhApromoter −15C/T (22.7%) were found in molecular clusters.M. tuberculosislineage 2 (includes Beijing genotype) was associated with any drug resistance (adjusted odds ratio [OR], 3.0; 95% confidence interval [CI], 1.7 to 5.6;P< 0.0001). Lineage 1 was associated withinhApromoter −15C/T mutations (OR, 6.4; 95% CI, 2.0 to 20.7;P= 0.002). We found that the genetic strain background influences the level of isoniazid resistance conveyed by particular mutations (interaction tests of drug resistance mutations across all lineages;P< 0.0001). In conclusion,M. tuberculosisdrug resistance mutations were associated with various levels of drug resistance and transmission, andM. tuberculosislineages were associated with particular drug resistance-conferring mutations and phenotypic drug resistance. Our study also supports a role for epistatic interactions between different drug resistance mutations and strain genetic backgrounds inM. tuberculosisdrug resistance.

scholarly journals Short Communication: Integrase Strand Transfer Inhibitors Drug Resistance Mutations in Puerto Rico HIV-Positive Individuals

2021 ◽  
Vol 18 (5) ◽  
pp. 2719
Author(s):  
Pablo López ◽  
Grissell Tirado ◽  
Andrea Arias ◽  
Raphael Sánchez ◽  
Elliott R. Rodríguez-López ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Puerto Rico ◽  
Resistance Mutation ◽  
Drug Resistance Mutation ◽  
Strand Transfer ◽  
Resistance Mutations ◽  
Drug Resistance Mutations ◽  
Therapeutic Procedures ◽  
Treatment Naïve ◽  
High Level

The HIV-1 integrase viral protein is responsible for incorporating the viral DNA into the genomic DNA. The inhibition of viral integration into host cell DNA is part of recent therapeutic procedures. Combination therapy with protease and reverse transcriptase inhibitors has demonstrated good synergistic results in reducing viral replication. The purpose of this study is to assess the occurrence of integrase drug resistance mutations from the period comprising 2013 through 2018 in Puerto Rico (PR). We analyzed 131 nucleotide sequences available in our HIV genotyping database, and we performed drug resistance mutation analyses using the Stanford HIV Drug Resistance Database. Twenty-one sequences (16.03%) harbored major or resistance-associated mutations. We identified the Q148HKR, G140S, Y143R, N155H, S147G, and E138EA major drug resistance mutations and the D232DN, T97TA, E157Q, G163GART accessory mutations. We detected high-level drug resistance to Elvitegravir and Raltegravir (76.19% and 85.71%). Moreover, we identified sequences harboring drug resistance mutations that could provide resistance to Dolutegravir. The transmission of strains with integrase antiretroviral resistance has been previously documented in treatment naïve patients. Given the increase of patients treated with integrase inhibitors, surveillance of drug resistance mutations is an essential aspect of PR’s clinical management of HIV infection.

scholarly journals High level of HIV-1 drug resistance mutations in patients with unsuppressed viral loads in rural northern South Africa

2017 ◽  
Vol 14 (1) ◽  
Author(s):  
Elizabeth M. Etta ◽  
Lufuno Mavhandu ◽  
Cecile Manhaeve ◽  
Keanan McGonigle ◽  
Patrick Jackson ◽  
...  
Keyword(s):  
South Africa ◽  
Drug Resistance ◽  
Resistance Mutations ◽  
Viral Loads ◽  
Drug Resistance Mutations ◽  
High Level ◽  
Hiv 1

scholarly journals HIV Drug Resistance Mutations Detection by Next-Generation Sequencing during Antiretroviral Therapy Interruption in China

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 264
Author(s):  
Miaomiao Li ◽  
Shujia Liang ◽  
Chao Zhou ◽  
Min Chen ◽  
Shu Liang ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Next Generation Sequencing ◽  
Antiretroviral Therapy ◽  
Detection Threshold ◽  
Next Generation ◽  
Resistance Mutations ◽  
Hiv Drug Resistance ◽  
Drug Resistance Mutations ◽  
Therapy Interruption ◽  
Generation Sequencing

Patients with antiretroviral therapy interruption have a high risk of virological failure when re-initiating antiretroviral therapy (ART), especially those with HIV drug resistance. Next-generation sequencing may provide close scrutiny on their minority drug resistance variant. A cross-sectional study was conducted in patients with ART interruption in five regions in China in 2016. Through Sanger and next-generation sequencing in parallel, HIV drug resistance was genotyped on their plasma samples. Rates of HIV drug resistance were compared by the McNemar tests. In total, 174 patients were included in this study, with a median 12 (interquartile range (IQR), 6–24) months of ART interruption. Most (86.2%) of them had received efavirenz (EFV)/nevirapine (NVP)-based first-line therapy for a median 16 (IQR, 7–26) months before ART interruption. Sixty-one (35.1%) patients had CRF07_BC HIV-1 strains, 58 (33.3%) CRF08_BC and 35 (20.1%) CRF01_AE. Thirty-four (19.5%) of the 174 patients were detected to harbor HIV drug-resistant variants on Sanger sequencing. Thirty-six (20.7%), 37 (21.3%), 42 (24.1%), 79 (45.4%) and 139 (79.9) patients were identified to have HIV drug resistance by next-generation sequencing at 20% (v.s. Sanger, p = 0.317), 10% (v.s. Sanger, p = 0.180), 5% (v.s. Sanger, p = 0.011), 2% (v.s. Sanger, p < 0.001) and 1% (v.s. Sanger, p < 0.001) of detection thresholds, respectively. K65R was the most common minority mutation, of 95.1% (58/61) and 93.1% (54/58) in CRF07_BC and CRF08_BC, respectively, when compared with 5.7% (2/35) in CRF01_AE (p < 0.001). In 49 patients that followed-up a median 10 months later, HIV drug resistance mutations at >20% frequency such as K103N, M184VI and P225H still existed, but with decreased frequencies. The prevalence of HIV drug resistance in ART interruption was higher than 15% in the survey. Next-generation sequencing was able to detect more minority drug resistance variants than Sanger. There was a sharp increase in minority drug resistance variants when the detection threshold was below 5%.

scholarly journals Nationwide Study of Drug Resistance Mutations in HIV-1 Infected Individuals under Antiretroviral Therapy in Brazil

2021 ◽  
Vol 22 (10) ◽  
pp. 5304
Author(s):  
Ana Santos-Pereira ◽  
Vera Triunfante ◽  
Pedro M. M. Araújo ◽  
Joana Martins ◽  
Helena Soares ◽  
...  
Keyword(s):  
Drug Resistance ◽  
People Living With Hiv ◽  
Resistance Mutations ◽  
Subtype C ◽  
Viral Loads ◽  
Drug Resistance Mutations ◽  
Subtype B ◽  
Low Prevalence ◽  
Living With Hiv ◽  
Hiv 1

The success of antiretroviral treatment (ART) is threatened by the emergence of drug resistance mutations (DRM). Since Brazil presents the largest number of people living with HIV (PLWH) in South America we aimed at understanding the dynamics of DRM in this country. We analyzed a total of 20,226 HIV-1 sequences collected from PLWH undergoing ART between 2008–2017. Results show a mild decline of DRM over the years but an increase of the K65R reverse transcriptase mutation from 2.23% to 12.11%. This increase gradually occurred following alterations in the ART regimens replacing zidovudine (AZT) with tenofovir (TDF). PLWH harboring the K65R had significantly higher viral loads than those without this mutation (p < 0.001). Among the two most prevalent HIV-1 subtypes (B and C) there was a significant (p < 0.001) association of K65R with subtype C (11.26%) when compared with subtype B (9.27%). Nonetheless, evidence for K65R transmission in Brazil was found both for C and B subtypes. Additionally, artificial neural network-based immunoinformatic predictions suggest that K65R could enhance viral recognition by HLA-B27 that has relatively low prevalence in the Brazilian population. Overall, the results suggest that tenofovir-based regimens need to be carefully monitored particularly in settings with subtype C and specific HLA profiles.

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