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Schmidlin, Apodaca, Newell, Sastokas, Kinsler, Geiler-Samerotte. Distinguishing mutants that resist drugs via different mechanisms by examining fitness tradeoffs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.17.562616. [PMID: 37905147 PMCID: PMC10614906 DOI: 10.1101/2023.10.17.562616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
There is growing interest in designing multidrug therapies that leverage tradeoffs to combat resistance. Tradeoffs are common in evolution and occur when, for example, resistance to one drug results in sensitivity to another. Major questions remain about the extent to which tradeoffs are reliable, specifically, whether the mutants that provide resistance to a given drug all suffer similar tradeoffs. This question is difficult because the drug-resistant mutants observed in the clinic, and even those evolved in controlled laboratory settings, are often biased towards those that provide large fitness benefits. Thus, the mutations (and mechanisms) that provide drug resistance may be more diverse than current data suggests. Here, we perform evolution experiments utilizing lineage-tracking to capture a fuller spectrum of mutations that give yeast cells a fitness advantage in fluconazole, a common antifungal drug. We then quantify fitness tradeoffs for each of 774 evolved mutants across 12 environments, finding these mutants group into 6 classes with characteristically different tradeoffs. Their unique tradeoffs may imply that each group of mutants affects fitness through different underlying mechanisms. Some of the groupings we find are surprising. For example, we find some mutants that resist single drugs do not resist their combination, while others do. And some mutants to the same gene have different tradeoffs than others. These findings, on one hand, demonstrate the difficulty in relying on consistent or intuitive tradeoffs when designing multidrug treatments. On the other hand, by demonstrating that hundreds of adaptive mutations can be reduced to a few groups with characteristic tradeoffs, our findings may yet empower multidrug strategies that leverage tradeoffs to combat resistance. More generally speaking, by grouping mutants that likely affect fitness through similar underlying mechanisms, our work guides efforts to map the phenotypic effects of mutation.
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Affiliation(s)
- Schmidlin
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
- School of Life Sciences, Arizona State University, Tempe AZ
| | - Apodaca
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
- School of Life Sciences, Arizona State University, Tempe AZ
| | - Newell
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
- School of Life Sciences, Arizona State University, Tempe AZ
| | - Sastokas
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
- School of Life Sciences, Arizona State University, Tempe AZ
| | - Kinsler
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
| | - Geiler-Samerotte
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
- School of Life Sciences, Arizona State University, Tempe AZ
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Yang S, Zhang W, Yang B, Feng X, Li Y, Li X, Liu Q. Metagenomic evidence for antibiotic-associated actinomycetes in the Karamay Gobi region. Front Microbiol 2024; 15:1330880. [PMID: 38505550 PMCID: PMC10949947 DOI: 10.3389/fmicb.2024.1330880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/07/2024] [Indexed: 03/21/2024] Open
Abstract
Due to the misuse of antibiotics, there is an increasing emergence and spread of multidrug-resistant (MDR) bacteria, leading to a human health crisis. To address clinical antibiotic resistance and prevent/control pathogenic microorganisms, the development of novel antibiotics is essential. This also offers a new approach to discovering valuable actinobacterial flora capable of producing natural bioactive products. In this study, we employed bioinformatics and macro-genome sequencing to collect 15 soil samples from three different locations in the Karamay Gobi region. First, we assessed the diversity of microorganisms in soil samples from different locations, analyzing the content of bacteria, archaea, actinomycetes, and fungi. The biodiversity of soil samples from outside the Gobi was found to be higher than that of soil samples from within and in the center of the Gobi. Second, through microbial interaction network analysis, we identified actinomycetes as the dominant group in the system. We have identified the top four antibiotic genes, such as Ecol_fabG_TRC, Efac_liaR_DAP, tetA (58), and macB, by CARD. These genes are associated with peptide antibiotics, disinfecting agents and antiseptics, tetracycline antibiotics, and macrolide antibiotics. In addition, we also obtained 40 other antibiotic-related genes through CARD alignment. Through in-depth analysis of desert soil samples, we identified several unstudied microbial species belonging to different families, including Erythrobacteriaceae, Solirubrobacterales, Thermoleophilaceae, Gaiellaceae, Nocardioidaceae, Actinomycetia, Egibacteraceae, and Acidimicrobiales. These species have the capability to produce peptide antibiotics, macrolide antibiotics, and tetracycline antibiotics, as well as disinfectants and preservatives. This study provides valuable theoretical support for future in-depth research.
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Affiliation(s)
- Shuai Yang
- Xinjiang Second Medical College, Xinjiang, China
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin Co-funded by Xinjiang Production & Construction Corps and The Ministry of Science & Technology, Tarim University, Alar, China
| | - Wei Zhang
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin Co-funded by Xinjiang Production & Construction Corps and The Ministry of Science & Technology, Tarim University, Alar, China
| | - Bo Yang
- Xinjiang Second Medical College, Xinjiang, China
| | - Xin Feng
- Xinjiang Second Medical College, Xinjiang, China
| | - Yiyang Li
- Xinjiang Second Medical College, Xinjiang, China
| | - Xiaolin Li
- Xinjiang Second Medical College, Xinjiang, China
| | - Qin Liu
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin Co-funded by Xinjiang Production & Construction Corps and The Ministry of Science & Technology, Tarim University, Alar, China
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Evolutionary Processes Driving the Rise and Fall of Staphylococcus aureus ST239, a Dominant Hybrid Pathogen. mBio 2021; 12:e0216821. [PMID: 34903061 PMCID: PMC8669471 DOI: 10.1128/mbio.02168-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Selection plays a key role in the spread of antibiotic resistance, but the evolutionary drivers of clinically important resistant strains remain poorly understood. Here, we use genomic analyses and competition experiments to study Staphylococcus aureus ST239, a prominent MRSA strain that is thought to have been formed by large-scale recombination between ST8 and ST30. Genomic analyses allowed us to refine the hybrid model for the origin of ST239 and to date the origin of ST239 to 1920 to 1945, which predates the clinical introduction of methicillin in 1959. Although purifying selection has dominated the evolution of ST239, parallel evolution has occurred in genes involved in antibiotic resistance and virulence, suggesting that ST239 has evolved toward an increasingly pathogenic lifestyle. Crucially, ST239 isolates have low competitive fitness relative to both ST8 and ST30 isolates, supporting the idea that fitness costs have driven the demise of this once-dominant pathogen strain.
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Kim SH, Chelliah R, Ramakrishnan SR, Perumal AS, Bang WS, Rubab M, Daliri EBM, Barathikannan K, Elahi F, Park E, Jo HY, Hwang SB, Oh DH. Review on Stress Tolerance in Campylobacter jejuni. Front Cell Infect Microbiol 2021; 10:596570. [PMID: 33614524 PMCID: PMC7890702 DOI: 10.3389/fcimb.2020.596570] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/03/2020] [Indexed: 01/17/2023] Open
Abstract
Campylobacter spp. are the leading global cause of bacterial colon infections in humans. Enteropathogens are subjected to several stress conditions in the host colon, food complexes, and the environment. Species of the genus Campylobacter, in collective interactions with certain enteropathogens, can manage and survive such stress conditions. The stress-adaptation mechanisms of Campylobacter spp. diverge from other enteropathogenic bacteria, such as Escherichia coli, Salmonella enterica serovar Typhi, S. enterica ser. Paratyphi, S. enterica ser. Typhimurium, and species of the genera Klebsiella and Shigella. This review summarizes the different mechanisms of various stress-adaptive factors on the basis of species diversity in Campylobacter, including their response to various stress conditions that enhance their ability to survive on different types of food and in adverse environmental conditions. Understanding how these stress adaptation mechanisms in Campylobacter, and other enteric bacteria, are used to overcome various challenging environments facilitates the fight against resistance mechanisms in Campylobacter spp., and aids the development of novel therapeutics to control Campylobacter in both veterinary and human populations.
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Affiliation(s)
- Se-Hun Kim
- Food Microbiology Division, Food Safety Evaluation Department, National Institute of Food and Drug Safety Evaluation, Cheongju, South Korea.,College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Ramachandran Chelliah
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Sudha Rani Ramakrishnan
- School of Food Science, Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | | | - Woo-Suk Bang
- Department of Food and Nutrition, College of Human Ecology and Kinesiology, Yeungnam University, Gyeongsan, South Korea
| | - Momna Rubab
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Eric Banan-Mwine Daliri
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Kaliyan Barathikannan
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Fazle Elahi
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Eunji Park
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Hyeon Yeong Jo
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Su-Bin Hwang
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Deog Hwan Oh
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
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Strong Environment-Genotype Interactions Determine the Fitness Costs of Antibiotic Resistance In Vitro and in an Insect Model of Infection. Antimicrob Agents Chemother 2020; 64:AAC.01033-20. [PMID: 32661001 DOI: 10.1128/aac.01033-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/08/2020] [Indexed: 11/20/2022] Open
Abstract
The acquisition of antibiotic resistance commonly imposes fitness costs, a reduction in the fitness of bacteria in the absence of drugs. These costs have been quantified primarily using in vitro experiments and a small number of in vivo studies in mice, and it is commonly assumed that these diverse methods are consistent. Here, we used an insect model of infection to compare the fitness costs of antibiotic resistance in vivo to those in vitro Experiments explored diverse mechanisms of resistance in a Gram-positive pathogen, Bacillus thuringiensis, and a Gram-negative intestinal symbiont, Enterobacter cloacae Rifampin resistance in B. thuringiensis showed fitness costs that were typically elevated in vivo, although these were modulated by genotype-environment interactions. In contrast, resistance to cefotaxime via derepression of AmpC β-lactamase in E. cloacae resulted in no detectable costs in vivo or in vitro, while spontaneous resistance to nalidixic acid, and carriage of the IncP plasmid RP4, imposed costs that increased in vivo Overall, fitness costs in vitro were a poor predictor of fitness costs in vivo because of strong genotype-environment interactions throughout this study. Insect infections provide a cheap and accessible means of assessing the fitness consequences of resistance mutations, data that are important for understanding the evolution and spread of resistance. This study emphasizes that the fitness costs imposed by particular mutations or different modes of resistance are extremely variable and that only a subset of these mutations is likely to be prevalent outside the laboratory.
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Bischofberger AM, Baumgartner M, Pfrunder‐Cardozo KR, Allen RC, Hall AR. Associations between sensitivity to antibiotics, disinfectants and heavy metals in natural, clinical and laboratory isolates of Escherichia coli. Environ Microbiol 2020; 22:2664-2679. [PMID: 32162766 PMCID: PMC7384044 DOI: 10.1111/1462-2920.14986] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/24/2020] [Accepted: 03/09/2020] [Indexed: 01/03/2023]
Abstract
Bacteria in nature often encounter non-antibiotic antibacterials (NAAs), such as disinfectants and heavy metals, and they can evolve resistance via mechanisms that are also involved in antibiotic resistance. Understanding whether susceptibility to different types of antibacterials is non-randomly associated across natural and clinical bacteria is therefore important for predicting the spread of resistance, yet there is no consensus about the extent of such associations or underlying mechanisms. We tested for associations between susceptibility phenotypes of 93 natural and clinical Escherichia coli isolates to various NAAs and antibiotics. Across all compound combinations, we detected a small number of non-random associations, including a trio of positive associations among chloramphenicol, triclosan and benzalkonium chloride. We investigated genetic mechanisms that can explain such associations using genomic information, genetic knockouts and experimental evolution. This revealed some mutations that are selected for by experimental exposure to one compound and confer cross-resistance to other compounds. Surprisingly, these interactions were asymmetric: selection for chloramphenicol resistance conferred cross-resistance to triclosan and benzalkonium chloride, but selection for triclosan resistance did not confer cross-resistance to other compounds. These results identify genetic changes involved in variable cross-resistance across antibiotics and NAAs, potentially contributing to associations in natural and clinical bacteria.
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Affiliation(s)
- Anna M. Bischofberger
- Institute of Integrative BiologyDepartment of Environmental Systems ScienceETH ZurichSwitzerland
| | - Michael Baumgartner
- Institute of Integrative BiologyDepartment of Environmental Systems ScienceETH ZurichSwitzerland
| | | | - Richard C. Allen
- Institute of Integrative BiologyDepartment of Environmental Systems ScienceETH ZurichSwitzerland
| | - Alex R. Hall
- Institute of Integrative BiologyDepartment of Environmental Systems ScienceETH ZurichSwitzerland
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Modified Antibiotic Adjuvant Ratios Can Slow and Steer the Evolution of Resistance: Co-amoxiclav as a Case Study. mBio 2019; 10:mBio.01831-19. [PMID: 31530673 PMCID: PMC6751059 DOI: 10.1128/mbio.01831-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As antibiotic resistance spreads, developing sustainable methods to restore the efficacy of existing antibiotics is increasingly important. One widespread method is to combine antibiotics with synergistically acting adjuvants that inhibit resistance mechanisms, allowing drug killing. Here we use co-amoxiclav (a clinically important combination of the β-lactam antibiotic amoxicillin and the β-lactamase inhibitor clavulanate) to ask whether treatment efficacy and resistance evolution can be decoupled via component dosing modifications. A simple mathematical model predicts that different ratios of these two drug components can produce distinct evolutionary responses irrespective of the initial efficacy. We test this hypothesis by selecting Escherichia coli with a plasmid-encoded β-lactamase (CTX-M-14), against different concentrations of amoxicillin and clavulanate. Consistent with our theory, we found that while resistance evolved under all conditions, the component ratio influenced both the rate and mechanism of resistance evolution. Specifically, we found that the current clinical practice of high amoxicillin-to-clavulanate ratios resulted in the most rapid adaptation to antibiotics via gene dosing responses. Increased plasmid copy number allowed E. coli to increase β-lactamase dosing and effectively titrate out low quantities of clavulanate, restoring amoxicillin resistance. In contrast, high clavulanate ratios were more robust-plasmid copy number did not increase, although porin or efflux resistance mechanisms were found, as for all drug ratios. Our results indicate that by changing the ratio of adjuvant to antibiotic we can slow and steer the path of resistance evolution. We therefore suggest using increased adjuvant dosing regimens to slow the rate of resistance evolution.IMPORTANCE As antibiotic resistance spreads, a promising approach is to restore the effectiveness of existing drugs via coadministration with adjuvants that inhibit resistance. However, as for monotherapy, antibiotic-adjuvant therapies can select for a variety of resistance mechanisms, so it is imperative that adjuvants be used in a sustainable manner. We test whether the rate of resistance evolution can be decoupled from treatment efficacy using co-amoxiclav, a clinically important combination of the β-lactam amoxicillin and β-lactamase inhibitor clavulanate. Using experimental evolution and a simple theoretical model, we show that the current co-amoxiclav formulation with a high proportion of amoxicillin rapidly selects for resistance via increased β-lactamase production. On the other hand, formulations with more clavulanate and less amoxicillin have similar efficacies yet prevent the selective benefit of increased β-lactamase. We suggest that by blocking common paths to resistance, treatment combinations with the adjuvant in excess can slow the evolution of resistance.
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Pilecky M, Schildberger A, Knabl L, Orth-Höller D, Weber V. Influence of antibiotic treatment on the detection of S. aureus in whole blood following pathogen enrichment. BMC Microbiol 2019; 19:180. [PMID: 31387527 PMCID: PMC6683330 DOI: 10.1186/s12866-019-1559-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/30/2019] [Indexed: 02/06/2023] Open
Abstract
Background Early pathogen detection and identification are crucial for an effective and targeted antibiotic therapy in patients suffering from blood stream infection. Molecular diagnostic methods can accelerate pathogen identification as compared to blood culture, but frequently suffer from the inhibition of polymerase chain reation (PCR) by sample matrix components, such as host DNA, anticoagulants, or plasma proteins. To overcome this limitation, molecular diagnostic methods commonly rely on pathogen enrichment by selective lysis of blood cells and pelleting of intact pathogens prior to analysis. Results Here, we investigated the impact of antibiotic treatment on the recovery of pathogen DNA using an established pathogen enrichment protocol. Based on the hypothesis that induction of bacterial cell wall disintegration following antibiotic administration leads to incomplete pelleting of pathogen DNA, S. aureus was grown in human whole blood with or without addition of cell wall active (vancomycin, piperacillin) or non cell wall active (ciprofloxacin, clindamycin) antibiotics at clinically relevant concentrations. Pathogen detection remained unaffected by non cell wall active antibiotics or even increased in the presence of cell wall active antibiotics, indicating improved accessibility of pathogen DNA. Likewise, mechanical lysis of S. aureus prior to pathogen enrichment resulted in increased recovery of pathogen DNA. Quantification of pathogen and human DNA after selective lysis of blood cells and pathogen enrichment confirmed partial depletion of human DNA, leading to a net enrichment of pathogen DNA over human DNA. Conclusion Concurrent antibiotic administration does not reduce the recovery of pathogen DNA during pathogen enrichment by selective lysis and centrifugation. Leads to a 10-fold human DNA depletion as compared to pathogen DNA. Moreover, we confirm that the recovery of pathogen DNA after pathogen enrichment is not negatively influenced by concurrent antibiotic administration. Electronic supplementary material The online version of this article (10.1186/s12866-019-1559-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthias Pilecky
- Center for Biomedical Technology, Department for Health Sciences and Biomedicine, Danube University Krems, Dr.-Karl-Dorrek-Strasse 30, 3500, Krems, Austria
| | - Anita Schildberger
- Center for Biomedical Technology, Department for Health Sciences and Biomedicine, Danube University Krems, Dr.-Karl-Dorrek-Strasse 30, 3500, Krems, Austria
| | - Ludwig Knabl
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstraße 41, A-6020, Innsbruck, Austria
| | - Dorothea Orth-Höller
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstraße 41, A-6020, Innsbruck, Austria
| | - Viktoria Weber
- Center for Biomedical Technology, Department for Health Sciences and Biomedicine, Danube University Krems, Dr.-Karl-Dorrek-Strasse 30, 3500, Krems, Austria. .,Christian Doppler Laboratory for Innovative Therapy Approaches in Sepsis, Department for Health Sciences and Biomedicine, Danube University Krems, Dr.-Karl-Dorrek-Strasse 30, 3500, Krems, Austria. .,Department for Biomedical Research, Danube University Krems, Dr.-Karl-Dorrek-Strasse 30, 3500, Krems, Austria.
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