scholarly journals Benzoate and Salicylate Tolerant Strains Lose Antibiotic Resistance during Laboratory Evolution ofEscherichia coliK-12

2016 ◽  
Author(s):  
Kaitlin E. Creamer ◽  
Frederick S. Ditmars ◽  
Preston J. Basting ◽  
Karina S. Kunka ◽  
Issam N. Hamdallah ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Gut Microbiome ◽  
Food Preservative ◽  
Large Deletions ◽  
Increased Sensitivity ◽  
K 12 ◽  
Similar Growth ◽  
External Ph ◽  
Mdr Genes

ABSTRACTEscherichia coliK-12 W3110 grows in the presence of membrane-permeant organic acids that can depress cytoplasmic pH and accumulate in the cytoplasm. We conducted experimental evolution by daily diluting cultures in increasing concentrations of benzoic acid (up to 20 mM) buffered at external pH 6.5, a pH at which permeant acids concentrate in the cytoplasm. By 2,000 generations, clones isolated from evolving populations showed increasing tolerance to benzoate but were sensitive to chloramphenicol and tetracycline. Sixteen clones grew to stationary phase in 20 mM benzoate, whereas the ancestral strain W3110 peaked and declined. Similar growth occurred in 10 mM salicylate. Benzoate-evolved strains grew like W3110 in the absence of benzoate; in media buffered at pH 4.8, pH 7.0, or pH 9.0; or in 20 mM acetate or sorbate at pH 6.5. Genomes of 16 strains revealed over 100 mutations including SNPs, large deletions, and insertion knockouts. Most strains acquired deletions in the benzoate-induced multiple antibiotic resistance (Mar) regulon or in associated regulators such asrobandcpxA, as well as MDR efflux pumpsemrA,emrY, andmdtA. Strains also lost or down-regulated the Gad acid fitness regulon. In 5 mM benzoate, or in 2 mM salicylate (2-hydroxybenzoate), most strains showed increased sensitivity to the antibiotics chloramphenicol and tetracycline; some strains were more sensitive than amarAknockout. Thus, our benzoate-evolved strains may reveal additional unknown drug resistance components. Benzoate or salicylate selection pressure may cause general loss of MDR genes and regulators.IMPORTANCEBenzoate is a common food preservative, and salicylate is the primary active metabolite of aspirin. In the gut microbiome, genetic adaptation to salicylate may involve loss or downregulation of inducible multidrug resistance systems. This discovery implies that aspirin therapy may modulate the human gut microbiome to favor salicylate tolerance at the expense of drug resistance. Similar aspirin-associated loss of drug resistance might occur in bacterial pathogens found in arterial plaques.

scholarly journals Benzoate- and Salicylate-Tolerant Strains of Escherichia coli K-12 Lose Antibiotic Resistance during Laboratory Evolution

2016 ◽  
Vol 83 (2) ◽  
Author(s):  
Kaitlin E. Creamer ◽  
Frederick S. Ditmars ◽  
Preston J. Basting ◽  
Karina S. Kunka ◽  
Issam N. Hamdallah ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Gut Microbiome ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
Large Deletions ◽  
Increased Sensitivity ◽  
K 12

ABSTRACT Escherichia coli K-12 W3110 grows in the presence of membrane-permeant organic acids that can depress cytoplasmic pH and accumulate in the cytoplasm. We conducted experimental evolution by daily diluting cultures in increasing concentrations of benzoic acid (up to 20 mM) buffered at external pH 6.5, a pH at which permeant acids concentrate in the cytoplasm. By 2,000 generations, clones isolated from evolving populations showed increasing tolerance to benzoate but were sensitive to chloramphenicol and tetracycline. Sixteen clones grew to stationary phase in 20 mM benzoate, whereas the ancestral strain W3110 peaked and declined. Similar growth occurred in 10 mM salicylate. Benzoate-evolved strains grew like W3110 in the absence of benzoate, in media buffered at pH 4.8, pH 7.0, or pH 9.0, or in 20 mM acetate or sorbate at pH 6.5. Genomes of 16 strains revealed over 100 mutations, including single-nucleotide polymorphisms (SNPs), large deletions, and insertion knockouts. Most strains acquired deletions in the benzoate-induced multiple antibiotic resistance (Mar) regulon or in associated regulators such as rob and cpxA, as well as the multidrug resistance (MDR) efflux pumps emrA, emrY, and mdtA. Strains also lost or downregulated the Gad acid fitness regulon. In 5 mM benzoate or in 2 mM salicylate (2-hydroxybenzoate), most strains showed increased sensitivity to the antibiotics chloramphenicol and tetracycline; some strains were more sensitive than a marA knockout strain. Thus, our benzoate-evolved strains may reveal additional unknown drug resistance components. Benzoate or salicylate selection pressure may cause general loss of MDR genes and regulators. IMPORTANCE Benzoate is a common food preservative, and salicylate is the primary active metabolite of aspirin. In the gut microbiome, genetic adaptation to salicylate may involve loss or downregulation of inducible multidrug resistance systems. This discovery implies that aspirin therapy may modulate the human gut microbiome to favor salicylate tolerance at the expense of drug resistance. Similar aspirin-associated loss of drug resistance might occur in bacterial pathogens found in arterial plaques.

scholarly journals Contagious Antibiotic Resistance: Plasmid Transfer Among Bacterial Residents of the Zebrafish Gut

2020 ◽  
Author(s):  
Wesley Loftie-Eaton ◽  
Angela Crabtree ◽  
David Perry ◽  
Jack Millstein ◽  
Barrie Robinson ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Gut Microbiome ◽  
Bacterial Communities ◽  
Plasmid Transfer ◽  
Multi Drug Resistance ◽  
Culturable Bacteria ◽  
Resistance Plasmid ◽  
Resistance Plasmids

AbstractBy characterizing the trajectories of antibiotic resistance gene transfer in bacterial communities such as the gut microbiome, we will better understand the factors that influence this spread of resistance. Our aim was to investigate the host network of a multi-drug resistance broad-host-range plasmid in the culturable gut microbiome of zebrafish. This was done through in vitro and in vivo conjugation experiments with Escherichia coli as donor of the plasmid pB10::gfp. When this donor was mixed with the extracted gut microbiome, only transconjugants of Aeromonas veronii were detected. In separate matings between the same donor and four prominent isolates from the gut microbiome, the plasmid transferred to two of these four isolates, A. veronii and Plesiomonas shigelloides, but not to Shewanella putrefaciens and Vibrio mimicus. When these A. veronii and P. shigelloides transconjugants were the donors in matings with the same four isolates, the plasmid now also transferred from A. veronii to S. putrefaciens. P. shigelloides was unable to donate the plasmid and V. mimicus was unable to acquire it. Finally, when the E. coli donor was added in vivo to zebrafish through their food, plasmid transfer was observed in the gut but only to Achromobacter sp., a rare member of the gut microbiome. This work shows that the success of plasmid-mediated antibiotic resistance spread in a gut microbiome depends on the donor-recipient species combinations and therefore their spatial arrangement. It also suggests that rare gut microbiome members should not be ignored as potential reservoirs of multi-drug resistance plasmids from food.ImportanceTo understand how antibiotic resistance plasmids end up in human pathogens it is crucial to learn how, where and when they are transferred and maintained in members of bacterial communities such as the gut microbiome. To gain insight into the network of plasmid-mediated antibiotic resistance sharing in the gut microbiome, we investigated the transferability and maintenance of a multi-drug resistance plasmid among the culturable bacteria of the zebrafish gut. We show that the success of plasmid-mediated antibiotic resistance spread in a gut microbiome can depend on which species are involved, as some are important nodes in the plasmid-host network and others dead-ends. Our findings also suggest that rare gut microbiome members should not be ignored as potential reservoirs of multi-drug resistance plasmids from food.

The gut microbiota resistome provides development of drug resistance in causative agents of human infectious diseases

2017 ◽  
pp. 20-32 ◽  
Author(s):  
Е.Н. Ильина ◽  
Е.И. Олехнович ◽  
А.В. Павленко
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Integrated Approach ◽  
Modern Medicine ◽  
Pathogenic Microorganisms ◽  
Human Pathogens ◽  
Potential Source ◽  
Causative Agents ◽  
Bacterial Genes

С течением времени подходы к изучению резистентности к антибиотикам трансформировались от сосредоточения на выделенных в виде чистой культуры патогенных микроорганизмах к исследованию резистентности на уровне микробных сообществ, составляющих биотопы человека и окружающей среды. По мере того, как продвигается изучение устойчивости к антибиотикам, возникает необходимость использования комплексного подхода для улучшения информирования мирового сообщества о наблюдаемых тенденциях в этой области. Все более очевидным становится то, что, хотя не все гены резистентности могут географически и филогенетически распространяться, угроза, которую они представляют, действительно серьезная и требует комплексных междисциплинарных исследований. В настоящее время резистентность к антибиотикам среди патогенов человека стала основной угрозой в современной медицине, и существует значительный интерес к определению ниши, в которых бактерии могут получить гены антибиотикорезистентности, и механизмов их передачи. В данном обзоре мы рассматриваем проблемы, возникшие на фоне широкого использования человечеством антибактериальных препаратов, в свете формирования микрофлорой кишечника резервуара генов резистентности. Over the time, studies of antibiotic resistance have transformed from focusing on pathogenic microorganisms isolated as a pure culture to analysis of resistance at the level of microbial communities that constitute human and environmental biotopes. Advancing studies of antibiotic resistance require an integrated approach to enhance availability of information about observed tendencies in this field to the global community. It becomes increasingly obvious that, even though not all resistance genes can geographically and phylogenetically spread, the threat they pose is indeed serious and requires complex interdisciplinary research. Currently, the antibiotic resistance of human pathogens has become a challenge to modern medicine, which is now focusing on determining a potential source for bacterial genes of drug resistance and mechanisms for the gene transmission. In this review, we discussed problems generated by the widespread use of antibacterial drugs in the light of forming a reservoir of resistance genes by gut microflora.

scholarly journals Exogenous Isolation of Antibiotic Resistance Plasmids from Piggery Manure Slurries Reveals a High Prevalence and Diversity of IncQ-Like Plasmids

2000 ◽  
Vol 66 (11) ◽  
pp. 4854-4862 ◽  
Author(s):  
Kornelia Smalla ◽  
Holger Heuer ◽  
Antje Götz ◽  
Dagmar Niemeyer ◽  
Ellen Krögerrecklenfort ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Ralstonia Eutropha ◽  
Blot Hybridization ◽  
Restriction Pattern ◽  
Pcr Analysis ◽  
Dot Blot ◽  
High Prevalence ◽  
Resistance Plasmids ◽  
Incq Plasmids ◽  
K 12

ABSTRACT Antibiotic resistance plasmids were exogenously isolated in biparental matings with piggery manure bacteria as plasmid donors inEscherichia coli CV601 and Pseudomonas putidaUWC1 recipients. Surprisingly, IncQ-like plasmids were detected by dot blot hybridization with an IncQ oriV probe in severalP. putida UWC1 transconjugants. The capture of IncQ-like plasmids in biparental matings indicates not only their high prevalence in manure slurries but also the presence of efficiently mobilizing plasmids. In order to elucidate unusual hybridization data (weak or no hybridization with IncQ repB or IncQ oriTprobes) four IncQ-like plasmids (pIE1107, pIE1115, pIE1120, and pIE1130), each representing a different EcoRV restriction pattern, were selected for a more thorough plasmid characterization after transfer into E. coli K-12 strain DH5α by transformation. The characterization of the IncQ-like plasmids revealed an astonishingly high diversity with regard to phenotypic and genotypic properties. Four different multiple antibiotic resistance patterns were found to be conferred by the IncQ-like plasmids. The plasmids could be mobilized by the RP4 derivative pTH10 into Acinetobactersp., Ralstonia eutropha, Agrobacterium tumefaciens, and P. putida, but they showed diverse patterns of stability under nonselective growth conditions in different host backgrounds. Incompatibility testing and PCR analysis clearly revealed at least two different types of IncQ-like plasmids. PCR amplification of total DNA extracted directly from different manure samples and other environments indicated the prevalence of both types of IncQ plasmids in manure, sewage, and farm soil. These findings suggest that IncQ plasmids play an important role in disseminating antibiotic resistance genes.

scholarly journals Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Yue Xing ◽  
Xiaoxi Kang ◽  
Siwei Zhang ◽  
Yujie Men
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Selective Pressure ◽  
Fold Increase ◽  
Streptomycin Resistance ◽  
Evolutionary Stage ◽  
Fitness Costs ◽  
Evolutionary Trajectories ◽  
K 12 ◽  
Late Stages

AbstractTo explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5–6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

Changing patterns and widening of antibiotic resistance inShigellaspp. over a decade (2000–2011), Andaman Islands, India

2014 ◽  
Vol 143 (3) ◽  
pp. 470-477 ◽  
Author(s):  
D. BHATTACHARYA ◽  
H. BHATTACHARYA ◽  
D. S. SAYI ◽  
A. P. BHARADWAJ ◽  
M. SINGHANIA ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Wide Spectrum ◽  
Resistance Pattern ◽  
Third Generation ◽  
Isolation And Identification ◽  
Antimicrobial Drugs ◽  
Drug Resistance Pattern ◽  
Resistance Patterns ◽  
Third Generation Cephalosporins

SUMMARYThis study is a part of the surveillance study on childhood diarrhoea in the Andaman and Nicobar Islands; here we report the drug resistance pattern of recent isolates ofShigellaspp. (2006–2011) obtained as part of that study and compare it with that ofShigellaisolates obtained earlier during 2000–2005. During 2006–2011, stool samples from paediatric diarrhoea patients were collected and processed for isolation and identification ofShigellaspp. Susceptibility to 22 antimicrobial drugs was tested and minimum inhibitory concentrations were determined for third-generation cephalosporins, quinolones, amoxicillin-clavulanic acid combinations and gentamicin. A wide spectrum of antibiotic resistance was observed in theShigellastrains obtained during 2006–2011. The proportions of resistant strains showed an increase from 2000–2005 to 2006–2011 in 20/22 antibiotics tested. The number of drug resistance patterns increased from 13 in 2000–2005 to 43 in 2006–2011. Resistance to newer generation fluoroquinolones, third-generation cephalosporins and augmentin, which was not observed during 2000–2005, appeared during 2006–2011. The frequency of resistance inShigellaisolates has increased substantially between 2000–2006 and 2006–2011, with a wide spectrum of resistance. At present, the option for antimicrobial therapy in shigellosis in Andaman is limited to a small number of drugs.

scholarly journals Deregulated FASN Expression in BRAF Inhibitor-Resistant Melanoma Cells Unveils New Targets for Drug Combinations

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2284
Author(s):  
Serena Stamatakos ◽  
Giovanni Luca Beretta ◽  
Elisabetta Vergani ◽  
Matteo Dugo ◽  
Cristina Corno ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Metastatic Melanoma ◽  
Mutant Cell ◽  
Braf Inhibitor ◽  
Cancer Cell Line ◽  
Melanoma Cells ◽  
Melanoma Progression ◽  
Increased Sensitivity ◽  
Resistant Cells

Metabolic changes promoting cell survival are involved in metastatic melanoma progression and in the development of drug resistance. In BRAF-inhibitor resistant melanoma cells, we explored the role of FASN, an enzyme involved in lipogenesis overexpressed in metastatic melanoma. Resistant melanoma cells displaying enhanced migratory and pro-invasive abilities increased sensitivity to the BRAF inhibitor PLX4032 upon the molecular targeting of FASN and upon treatment with the FASN inhibitor orlistat. This behavior was associated with a marked apoptosis and caspase 3/7 activation observed for the drug combination. The expression of FASN was found to be inversely associated with drug resistance in BRAF-mutant cell lines, both in a set of six resistant/sensitive matched lines and in the Cancer Cell Line Encyclopedia. A favorable drug interaction in resistant cells was also observed with U18666 A inhibiting DHCR24, which increased upon FASN targeting. The simultaneous combination of the two inhibitors showed a synergistic interaction with PLX4032 in resistant cells. In conclusion, FASN plays a role in BRAF-mutated melanoma progression, thereby creating novel therapeutic opportunities for the treatment of melanoma.

scholarly journals Extreme genome selection towards complete antimicrobial resistance in a nosocomial strain of Stenotrophomonas maltophilia complex

2019 ◽  
Author(s):  
Sanjeet Kumar ◽  
Kanika Bansal ◽  
Prashant P. Patil ◽  
Amandeep Kaur ◽  
Satinder Kaur ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Stenotrophomonas Maltophilia ◽  
Antibiotic Resistance Genes ◽  
Chromosomal Origin ◽  
Extreme Drug Resistance

ABSTRACTWe report first complete genome sequence and analysis of an extreme drug resistance (XDR) nosocomial Stenotrophomonas maltophilia that is resistant to the mainstream drugs i.e. trimethoprim/sulfamethoxazole (TMP/SXT) and levofloxacin. Taxonogenomic analysis revealed it to be a novel genomospecies of the Stenotrophomonas maltophilia complex (Smc). Comprehensive genomic investigation revealed fourteen dynamic regions (DRs) exclusive to SM866, consisting of diverse antibiotic resistance genes, efflux pumps, heavy metal resistance, various transcriptional regulators etc. Further, resistome analysis of Smc clearly depicted SM866 to be an enriched strain, having diversified resistome consisting of sul1 and sul2 genes. Interestingly, SM866 does not have any plasmid but it harbors two diverse super-integrons of chromosomal origin. Apart from genes for sulfonamide resistance (sul1 and sul2), both of these integrons harbor an array of antibiotic resistance genes linked to ISCR (IS91-like elements common regions) elements. These integrons also harbor genes encoding resistance to commonly used disinfectants like quaternary ammonium compounds and heavy metals like mercury. Hence, isolation of a novel strain belonging to a novel sequence type (ST) and genomospecies with diverse array of resistance from a tertiary care unit of India indicates extent and nature of selection pressure driving XDRs in hospital settings. There is an urgent need to employ complete genome based investigation using emerging technologies for tracking emergence of XDR at the global level and designing strategies of sanitization and antibiotic regime.Impact StatementThe hospital settings in India have one of the highest usage of antimicrobials and heavy patient load. Our finding of a novel clinical isolate of S. maltophilia complex with two super-integrons harbouring array of antibiotic resistance genes along with antimicrobials resistance genes indicates the extent and the nature of selection pressures in action. Further, the presence of ISCR type of transposable elements on both integrons not only indicates its propensity to transfer resistome but also their chromosomal origin suggests possibilities for further genomic/phenotypic complexities. Such complex cassettes and strain are potential threat to global health care. Hence, there is an urgent need to employ cost-effective long read technologies to keep vigilance on novel and extreme antimicrobial resistance pathogens in populous countries. There is also need for surveillance for usage of antimicrobials for hygiene and linked/rapid co-evolution of extreme drug resistance in nosocomial pathogens. Our finding of the chromosomal encoding XDR will shed a light on the need of hour to understand the evolution of an opportunistic nosocomial pathogen belonging to S. maltophilia.RepositoriesComplete genome sequence of Stenotrophomonas maltophilia SM866: CP031058

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