1
|
Levin BR, Berryhill BA, Gil-Gil T, Manuel JA, Smith AP, Choby JE, Andersson DI, Weiss DS, Baquero F. Theoretical considerations and empirical predictions of the pharmaco- and population dynamics of heteroresistance. Proc Natl Acad Sci U S A 2024; 121:e2318600121. [PMID: 38588431 PMCID: PMC11032463 DOI: 10.1073/pnas.2318600121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 02/28/2024] [Indexed: 04/10/2024] Open
Abstract
Antibiotics are considered one of the most important contributions to clinical medicine in the last century. Due to the use and overuse of these drugs, there have been increasing frequencies of infections with resistant pathogens. One form of resistance, heteroresistance, is particularly problematic; pathogens appear sensitive to a drug by common susceptibility tests. However, upon exposure to the antibiotic, resistance rapidly ascends, and treatment fails. To quantitatively explore the processes contributing to the emergence and ascent of resistance during treatment and the waning of resistance following cessation of treatment, we develop two distinct mathematical and computer-simulation models of heteroresistance. In our analysis of the properties of these models, we consider the factors that determine the response to antibiotic-mediated selection. In one model, heteroresistance is progressive, with each resistant state sequentially generating a higher resistance level. In the other model, heteroresistance is non-progressive, with a susceptible population directly generating populations with different resistance levels. The conditions where resistance will ascend in the progressive model are narrower than those of the non-progressive model. The rates of reversion from the resistant to the sensitive states are critically dependent on the transition rates and the fitness cost of resistance. Our results demonstrate that the standard test used to identify heteroresistance is insufficient. The predictions of our models are consistent with empirical results. Our results demand a reevaluation of the definition and criteria employed to identify heteroresistance. We recommend that the definition of heteroresistance should include a consideration of the rate of return to susceptibility.
Collapse
Affiliation(s)
- Bruce R. Levin
- Department of Biology, Emory University, Atlanta, GA30322
- Emory Antibiotic Resistance Center, Atlanta, GA30322
| | - Brandon A. Berryhill
- Department of Biology, Emory University, Atlanta, GA30322
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA30322
| | - Teresa Gil-Gil
- Department of Biology, Emory University, Atlanta, GA30322
| | | | | | - Jacob E. Choby
- Emory Antibiotic Resistance Center, Atlanta, GA30322
- Emory Vaccine Center, Atlanta, GA30322
| | - Dan I. Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, UppsalaSE-75123, Sweden
| | - David S. Weiss
- Emory Antibiotic Resistance Center, Atlanta, GA30322
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA30322
- Georgia Emerging Infections Program, Georgia Department of Public Health, Atlanta, GA30322
| | - Fernando Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Biomédica en Red Epidemiología y Salud Pública, Madrid28034, Spain
| |
Collapse
|
2
|
Ochoa-Sánchez LE, Martínez JL, Gil-Gil T. Evolution of Resistance against Ciprofloxacin, Tobramycin, and Trimethoprim/Sulfamethoxazole in the Environmental Opportunistic Pathogen Stenotrophomonas maltophilia. Antibiotics (Basel) 2024; 13:330. [PMID: 38667006 PMCID: PMC11047544 DOI: 10.3390/antibiotics13040330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 03/27/2024] [Accepted: 04/02/2024] [Indexed: 04/29/2024] Open
Abstract
Stenotrophomonas maltophilia is an opportunistic pathogen that produces respiratory infections in immunosuppressed and cystic fibrosis patients. The therapeutic options to treat S. maltophilia infections are limited since it exhibits resistance to a wide variety of antibiotics such as β-lactams, aminoglycosides, tetracyclines, cephalosporins, macrolides, fluoroquinolones, or carbapenems. The antibiotic combination trimethoprim/sulfamethoxazole (SXT) is the treatment of choice to combat infections caused by S. maltophilia, while ceftazidime, ciprofloxacin, or tobramycin are used in most SXT-resistant infections. In the current study, experimental evolution and whole-genome sequencing (WGS) were used to examine the evolutionary trajectories of S. maltophilia towards resistance against tobramycin, ciprofloxacin, and SXT. The genetic changes underlying antibiotic resistance, as well as the evolutionary trajectories toward that resistance, were determined. Our results determine that genomic changes in the efflux pump regulatory genes smeT and soxR are essential to confer resistance to ciprofloxacin, and the mutation in the rplA gene is significant in the resistance to tobramycin. We identified mutations in folP and the efflux pump regulator smeRV as the basis of SXT resistance. Detailed and reliable knowledge of ciprofloxacin, tobramycin, and SXT resistance is essential for safe and effective use in clinical settings. Herein, we were able to prove once again the extraordinary ability that S. maltophilia has to acquire resistance and the importance of looking for alternatives to combat this resistance.
Collapse
Affiliation(s)
- Luz Edith Ochoa-Sánchez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, 28049 Madrid, Spain;
| | - José Luis Martínez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, 28049 Madrid, Spain;
| | - Teresa Gil-Gil
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, 28049 Madrid, Spain;
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| |
Collapse
|
3
|
Ismail AS, Berryhill BA, Gil-Gil T, Manuel JA, Smith AP, Baquero F, Levin BR. The Tradeoffs Between Persistence and Mutation Rates at Sub-Inhibitory Antibiotic Concentrations in Staphylococcus aureus. bioRxiv 2024:2024.04.01.587561. [PMID: 38617265 PMCID: PMC11014548 DOI: 10.1101/2024.04.01.587561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The rational design of the antibiotic treatment of bacterial infections employs these drugs to reach concentrations that exceed the minimum needed to prevent the replication of the target bacteria. However, within a treated patient, spatial and physiological heterogeneity promotes antibiotic gradients such that the concentration of antibiotics at specific sites is below the minimum needed to inhibit bacterial growth. Here, we investigate the effects of sub-inhibitory antibiotic concentrations on three parameters central to bacterial infection and the success of antibiotic treatment, using in vitro experiments with Staphylococcus aureus and mathematical-computer simulation models. Our results, using drugs of six different classes, demonstrate that exposure to sub-inhibitory antibiotic concentrations not only alters the dynamics of bacterial growth but also increases the mutation rate to antibiotic resistance and decreases the rate of production of persister cells thereby reducing the persistence level. Understanding this trade-off between mutation rates and persistence levels resulting from sub-inhibitory antibiotic exposure is crucial for optimizing, and mitigating the failure of, antibiotic therapy.
Collapse
Affiliation(s)
| | - Brandon A. Berryhill
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Teresa Gil-Gil
- Department of Biology, Emory University, Atlanta, Georgia, USA
| | | | - Andrew P. Smith
- Department of Biology, Emory University, Atlanta, Georgia, USA
| | - Fernando Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Médica en Red, Epidemiología y Salud Pública (CIBERESP) Madrid, Spain
| | - Bruce R. Levin
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University, Atlanta, Georgia, USA
| |
Collapse
|
4
|
Laborda P, Alcalde-Rico M, Gil-Gil T, Martínez JL, Blanco P. Biosensors for Inducers of Transient Antibiotic Resistance. Methods Mol Biol 2024; 2721:103-121. [PMID: 37819518 DOI: 10.1007/978-1-0716-3473-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
The acquisition of an antibiotic resistance phenotype can be due to genetic modifications (heritable) or transient changes in bacterial physiology (non-heritable). Induction of the expression of multidrug efflux pumps by specific compounds/growth conditions is one of the causes of Pseudomonas aeruginosa transient resistance. Biosensor strains have been used for decades to analyze real-time changes in transcription and (less frequently) translation of different genes, in different mutants, growing under several conditions or in the presence of different compounds. Among them, those based on bioluminescence or fluorescence are the most amenable for the real-time analysis of transcription. In this chapter, we describe the methods for constructing fluorescence- and bioluminescence-based biosensors to monitor the P. aeruginosa efflux pumps expression, as well as the use of these biosensors to identify compounds capable of inducing the expression of these antibiotic resistance determinants and, consequently, triggering transient resistance to antimicrobials.
Collapse
Affiliation(s)
- Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Manuel Alcalde-Rico
- Grupo de Resistencia Antimicrobiana en Bacterias Patógenas y Ambientales (GRABPA), Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Millennium Nucleus for Collaborative Research on Bacterial Resistance (MICROB-R), Valparaíso, Chile
| | | | | | - Paula Blanco
- Molecular Basis of Adaptation, Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| |
Collapse
|
5
|
Gil-Gil T, Martínez JL. Role of the phosphotransferase system in the transport of fosfomycin in Escherichia coli. Int J Antimicrob Agents 2024; 63:107027. [PMID: 37926273 DOI: 10.1016/j.ijantimicag.2023.107027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/23/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
The inducible inner membrane transporters, UhpT and GlpT are considered to be unique fosfomycin transporters. Glucose-6-phosphate, the substrate for UhpT, enhances fosfomycin activity. Previous work indicates that the fructose phosphotransferase system (PTS) might be involved in fosfomycin transport in the bacterial species, Stenotrophomonas maltophilia. Fosfomycin transport in Escherichia coli has been extensively studied and characterised. The current paper addresses the potential fosfomycin transport activity of the fructose PTS in E. coli. Notably, the deletion of both fructose-specific and general PTS proteins in E. coli increases fosfomycin resistance, which indicates that fructose PTS is involved in fosfomycin transport in E. coli. Further, although inactivation of UhpT, the canonical fosfomycin transporter, in E. coli increases fosfomycin resistance by 2-fold, inactivation of genes encoding the PTS increases it by up to 256-fold. Moreover, intracellular accumulation declines in the absence of both transporters, being mutations in the PTS associated with a larger decline. The results presented in this paper re-open the study of fosfomycin transport and reveal the role of the PTS in the transport of this bactericidal antibiotic in E. coli.
Collapse
Affiliation(s)
- Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC. Darwin 3. 28049, Madrid, Spain.
| | | |
Collapse
|
6
|
Gil-Gil T, Valverde JR, Martínez JL, Corona F. In vivo genetic analysis of Pseudomonas aeruginosa carbon catabolic repression through the study of CrcZ pseudo-revertants shows that Crc-mediated metabolic robustness is needed for proficient bacterial virulence and antibiotic resistance. Microbiol Spectr 2023; 11:e0235023. [PMID: 37902380 PMCID: PMC10714802 DOI: 10.1128/spectrum.02350-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
IIMPORTANCE Hfq and Crc regulate P. aeruginosa carbon catabolic repression at the post-transcriptional level. In vitro work has shown that Hfq binds the target RNAs and Crc stabilizes the complex. A third element in the regulation is the small RNA CrcZ, which sequesters the Crc-Hfq complex under no catabolic repression conditions, allowing the translation of the target mRNAs. A ΔcrcZ mutant was generated and presented fitness defects and alterations in its virulence potential and antibiotic resistance. Eight pseudo-revertants that present different degrees of fitness compensation were selected. Notably, although Hfq is the RNA binding protein, most mutations occurred in Crc. This indicates that Crc is strictly needed for P. aeruginosa efficient carbon catabolic repression in vivo. The compensatory mutations restore in a different degree the alterations in antibiotic susceptibility and virulence of the ΔcrcZ mutant, supporting that Crc plays a fundamental role linking P. aeruginosa metabolic robustness, virulence, and antibiotic resistance.
Collapse
|
7
|
Genova R, Gil-Gil T, Cuesta T, Martínez JL, Sanz-García F. The Inactivation of the Putative Two-Component System Sensor PA14_27940 Increases the Susceptibility to Several Antibiotics and Reduces the Motility of Pseudomonas aeruginosa. Int J Mol Sci 2023; 24:17355. [PMID: 38139182 PMCID: PMC10743758 DOI: 10.3390/ijms242417355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
The identification of targets whose inactivation increases the activity of antibiotics helps to fight antibiotic resistance. Previous work showed that a transposon-insertion mutant in the gene PA14_27940 increases Pseudomonas aeruginosa susceptibility to aminoglycosides. Since polar effects may affect the phenotype, in the present work, we generated an in-frame PA14_27940 deletion mutant. A PA14_27940 deletion increased the susceptibility to aminoglycosides, tetracycline, tigecycline, erythromycin and fosfomycin. Excepting fosfomycin, the other antibiotics are inducers of the MexXY efflux pump. MexXY induction is required for P. aeruginosa resistance to these antibiotics, which is post-transcriptionally regulated by the anti-repressor ArmZ. Although mexXY is inducible by tobramycin in ΔPA14_27940, the induction level is lower than in the parental PA14 strain. Additionally, armZ is induced by tobramycin in PA14 and not in ΔPA14_27940, supporting that ΔPA14_27940 presents an ArmZ-mediated defect in mexXY induction. For its part, hypersusceptibility to fosfomycin may be due to a reduced expression of nagZ and agmK, which encode enzymes of the peptidoglycan recycling pathway. ΔPA14_27940 also presents defects in motility, an element with relevance in P. aeruginosa's virulence. Overall, our results support that PA14_27940 is a good target for the search of adjuvants that will increase the activity of antibiotics and reduce the virulence of P. aeruginosa.
Collapse
Affiliation(s)
- Roberta Genova
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, 28049 Madrid, Spain; (R.G.); (T.G.-G.); (T.C.)
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Teresa Gil-Gil
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, 28049 Madrid, Spain; (R.G.); (T.G.-G.); (T.C.)
- EcLF Laboratory, Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Trinidad Cuesta
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, 28049 Madrid, Spain; (R.G.); (T.G.-G.); (T.C.)
| | - José Luis Martínez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, 28049 Madrid, Spain; (R.G.); (T.G.-G.); (T.C.)
| | - Fernando Sanz-García
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Darwin 3, 28049 Madrid, Spain; (R.G.); (T.G.-G.); (T.C.)
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, Domingo Miral sn, 50009 Zaragoza, Spain
| |
Collapse
|
8
|
Gil-Gil T, Berryhill BA, Manuel JA, Smith AP, McCall IC, Baquero F, Levin BR. The Evolution of Heteroresistance via Small Colony Variants in Escherichia coli Following Long Term Exposure to Bacteriostatic Antibiotics. bioRxiv 2023:2023.10.30.564761. [PMID: 37961139 PMCID: PMC10634941 DOI: 10.1101/2023.10.30.564761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Traditionally, bacteriostatic antibiotics are agents able to arrest bacterial growth. Despite being unable to kill bacterial cells, when they are used clinically the outcome of these drugs is frequently as effective as when a bactericidal drug is used. We explore the dynamics of Escherichia coli after exposure to two ribosome-targeting bacteriostatic antibiotics, chloramphenicol and azithromycin, for thirty days. The results of our experiments provide evidence that bacteria exposed to these drugs replicate, evolve, and generate a sub-population of small colony variants (SCVs) which are resistant to multiple drugs. These SCVs contribute to the evolution of heteroresistance and rapidly revert to a susceptible state once the antibiotic is removed. Stated another way, exposure to bacteriostatic drugs selects for the evolution of heteroresistance in populations previously lacking this trait. More generally, our results question the definition of bacteriostasis as populations exposed to bacteriostatic drugs are replicating despite the lack of net growth.
Collapse
Affiliation(s)
- Teresa Gil-Gil
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Brandon A. Berryhill
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University; Atlanta, GA, 30322, USA
| | - Joshua A. Manuel
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Andrew P. Smith
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Ingrid C. McCall
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Fernando Baquero
- Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Médica en Red, Epidemiologíy Salud Pública (CIBERESP) Madrid, Spain
| | - Bruce R. Levin
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| |
Collapse
|
9
|
Levin BR, Berryhill BA, Gil-Gil T, Manuel JA, Smith AP, Choby JE, Andersson DI, Weiss DS, Baquero F. Theoretical Considerations and Empirical Predictions of the Pharmaco- and Population Dynamics of Heteroresistance. bioRxiv 2023:2023.09.21.558832. [PMID: 37790545 PMCID: PMC10542493 DOI: 10.1101/2023.09.21.558832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Antibiotics are considered one of the most important contributions to clinical medicine in the last 100 years. Due to the use and overuse of these drugs, there have been increasing frequencies of infections with resistant pathogens. One form of resistance, heteroresistance, is particularly problematic; pathogens appear sensitive to a drug by common susceptibility tests. However, upon exposure to the antibiotic, resistance rapidly ascends, and treatment fails. To quantitatively explore the processes contributing to the emergence and ascent of resistance during treatment and the waning of resistance following cessation of treatment, we develop two distinct mathematical and computer-simulations models of heteroresistance. In our analysis of the properties of these models, we consider the factors that determine the response to antibiotic-mediated selection. In one model, heteroresistance is progressive, with each resistant state sequentially generating a higher resistance level. In the other model, heteroresistance is non-progressive, with a susceptible population directly generating populations with different resistance levels. The conditions where resistance will ascend in the progressive model are narrower than those of the non-progressive model. The rates of reversion from the resistant to the sensitive states are critically dependent on the transition rates and the fitness cost of resistance. Our results demonstrate that the standard test used to identify heteroresistance is insufficient. The predictions of our models are consistent with empirical results. Our results demand a reevaluation of the definition and criteria employed to identify heteroresistance. We recommend the definition of heteroresistance should include a consideration of the rate of return to susceptibility.
Collapse
Affiliation(s)
- Bruce R. Levin
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
- Emory Antibiotic Resistance Center; Atlanta, Georgia, 30322, USA
| | - Brandon A. Berryhill
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University; Atlanta, GA, 30322, USA
| | - Teresa Gil-Gil
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Joshua A. Manuel
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Andrew P. Smith
- Department of Biology, Emory University; Atlanta, Georgia, 30322, USA
| | - Jacob E. Choby
- Emory Antibiotic Resistance Center; Atlanta, Georgia, 30322, USA
- Emory Vaccine Center; Atlanta, Georgia, 30322, USA
| | - Dan I. Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, SE-75123, Sweden
| | - David S. Weiss
- Emory Antibiotic Resistance Center; Atlanta, Georgia, 30322, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine; Atlanta, GA, 30322, USA
- Georgia Emerging Infections Program, Georgia Department of Public Health; Atlanta, GA, 30322, USA
| | - Fernando Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Médica en Red, Epidemiología y Salud Pública (CIBERESP) Madrid, Spain
| |
Collapse
|
10
|
Sanz-García F, Gil-Gil T, Laborda P, Blanco P, Ochoa-Sánchez LE, Baquero F, Martínez JL, Hernando-Amado S. Translating eco-evolutionary biology into therapy to tackle antibiotic resistance. Nat Rev Microbiol 2023; 21:671-685. [PMID: 37208461 DOI: 10.1038/s41579-023-00902-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2023] [Indexed: 05/21/2023]
Abstract
Antibiotic resistance is currently one of the most important public health problems. The golden age of antibiotic discovery ended decades ago, and new approaches are urgently needed. Therefore, preserving the efficacy of the antibiotics currently in use and developing compounds and strategies that specifically target antibiotic-resistant pathogens is critical. The identification of robust trends of antibiotic resistance evolution and of its associated trade-offs, such as collateral sensitivity or fitness costs, is invaluable for the design of rational evolution-based, ecology-based treatment approaches. In this Review, we discuss these evolutionary trade-offs and how such knowledge can aid in informing combination or alternating antibiotic therapies against bacterial infections. In addition, we discuss how targeting bacterial metabolism can enhance drug activity and impair antibiotic resistance evolution. Finally, we explore how an improved understanding of the original physiological function of antibiotic resistance determinants, which have evolved to reach clinical resistance after a process of historical contingency, may help to tackle antibiotic resistance.
Collapse
Affiliation(s)
- Fernando Sanz-García
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, Zaragoza, Spain
| | - Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Darwin 3, Madrid, Spain
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, Darwin 3, Madrid, Spain
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
- Department of Clinical Microbiology, 9301, Rigshospitalet, Copenhagen, Denmark
| | - Paula Blanco
- Molecular Basis of Adaptation, Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain
| | | | - Fernando Baquero
- Department of Microbiology, Hospital Universitario Ramón y Cajal (IRYCIS), CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | | |
Collapse
|
11
|
Gil-Gil T, Cuesta T, Hernando-Amado S, Reales-Calderón JA, Corona F, Linares JF, Martínez JL. Virulence and Metabolism Crosstalk: Impaired Activity of the Type Three Secretion System (T3SS) in a Pseudomonas aeruginosa Crc-Defective Mutant. Int J Mol Sci 2023; 24:12304. [PMID: 37569678 PMCID: PMC10419072 DOI: 10.3390/ijms241512304] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous nosocomial opportunistic pathogen that harbors many virulence determinants. Part of P. aeruginosa success colonizing a variety of habitats resides in its metabolic robustness and plasticity, which are the basis of its capability of adaptation to different nutrient sources and ecological conditions, including the infected host. Given this situation, it is conceivable that P. aeruginosa virulence might be, at least in part, under metabolic control, in such a way that virulence determinants are produced just when needed. Indeed, it has been shown that the catabolite repression control protein Crc, which together with the RNA chaperon Hfq regulates the P. aeruginosa utilization of carbon sources at the post-transcriptional level, also regulates, directly or indirectly, virulence-related processes in P. aeruginosa. Among them, Crc regulates P. aeruginosa cytotoxicity, likely by modulating the activity of the Type III Secretion System (T3SS), which directly injects toxins into eukaryotic host cells. The present work shows that the lack of Crc produces a Type III Secretion-defective phenotype in P. aeruginosa. The observed impairment is a consequence of a reduced expression of the genes encoding the T3SS, together with an impaired secretion of the proteins involved. Our results support that the impaired T3SS activity of the crc defective mutant is, at least partly, a consequence of a defective protein export, probably due to a reduced proton motive force. This work provides new information about the complex regulation of the expression and the activity of the T3SS in P. aeruginosa. Our results highlight the need of a robust bacterial metabolism, which is defective in the ∆crc mutant, to elicit complex and energetically costly virulence strategies, as that provided by the T3SS.
Collapse
Affiliation(s)
- Teresa Gil-Gil
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Trinidad Cuesta
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Sara Hernando-Amado
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Jose Antonio Reales-Calderón
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Fernando Corona
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Juan F. Linares
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - José L. Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| |
Collapse
|
12
|
Berryhill BA, Gil-Gil T, Manuel JA, Smith AP, Margollis E, Baquero F, Levin BR. What's the Matter with MICs: Bacterial Nutrition, Limiting Resources, and Antibiotic Pharmacodynamics. Microbiol Spectr 2023; 11:e0409122. [PMID: 37130356 PMCID: PMC10269441 DOI: 10.1128/spectrum.04091-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 03/21/2023] [Indexed: 05/04/2023] Open
Abstract
The MIC of an antibiotic required to prevent replication is used both as a measure of the susceptibility/resistance of bacteria to that drug and as the single pharmacodynamic parameter for the rational design of antibiotic treatment regimes. MICs are experimentally estimated in vitro under conditions optimal for the action of the antibiotic. However, bacteria rarely grow in these optimal conditions. Using a mathematical model of the pharmacodynamics of antibiotics, we make predictions about the nutrient dependency of bacterial growth in the presence of antibiotics. We test these predictions with experiments in broth and a glucose-limited minimal media with Escherichia coli and eight different antibiotics. Our experiments question the sufficiency of using MICs and simple pharmacodynamic functions as measures of the pharmacodynamics of antibiotics under the nutritional conditions of infected tissues. To an extent that varies among drugs: (i) the estimated MICs obtained in rich media are greater than those estimated in minimal media; (ii) exposure to these drugs increases the time before logarithmic growth starts, their lag; and (iii) the stationary-phase density of E. coli populations declines with greater sub-MIC antibiotic concentrations. We postulate a mechanism to account for the relationship between sub-MICs of antibiotics and these growth parameters. This study is limited to a single bacterial strain and two types of culture media with different nutritive content. These limitations aside, the results of our study clearly question the use of MIC as the unique pharmacodynamic parameter to develop therapeutically oriented protocols. IMPORTANCE For studies of antibiotics and how they work, the most-often used measurement of drug efficacy is the MIC. The MIC is the concentration of an antibiotic needed to inhibit bacterial growth. This parameter is critical to the design and implementation of antibiotic therapy. We provide evidence that the use of MIC as the sole measurement for antibiotic efficacy ignores important aspects of bacterial growth dynamics. Before now, there has not been a nexus between bacteria, the conditions in which they grow, and the MIC. Most importantly, few studies have considered sub-MICs of antibiotics, despite their clinical importance. Here, we explore these concentrations in-depth, and we demonstrate MIC to be an incomplete measure of how an infection will interact with a specific antibiotic. Understanding the critiques of MIC is the first of many steps needed to improve infectious disease treatment.
Collapse
Affiliation(s)
- Brandon A. Berryhill
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Teresa Gil-Gil
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Andrew P. Smith
- Department of Biology, Emory University, Atlanta, Georgia, USA
| | - Ellie Margollis
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Fernando Baquero
- Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, and Centro de Investigación Médica en Red, Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Bruce R. Levin
- Department of Biology, Emory University, Atlanta, Georgia, USA
| |
Collapse
|
13
|
Gil-Gil T, Laborda P, Ochoa-Sánchez LE, Martínez JL, Hernando-Amado S. Efflux in Gram-negative bacteria: what are the latest opportunities for drug discovery? Expert Opin Drug Discov 2023; 18:671-686. [PMID: 37199662 DOI: 10.1080/17460441.2023.2213886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
INTRODUCTION The resistance-nodulation-division (RND) family is the most important group of multidrug efflux pumps in Gram-negative bacteria. Their inhibition increases the susceptibility of these microorganisms to antibiotics. The study of the effect of efflux pumps' overexpression on bacterial physiology in antibiotic-resistant mutants allows for the identification of exploitable weaknesses associated with resistance acquisition. AREAS COVERED The authors describe different RND multidrug efflux pumps' inhibition strategies and provide examples of inhibitors. This review also discusses inducers of the expression of efflux pumps, used in human therapy that can produce transient resistance to antibiotics in vivo. Since RND efflux pumps may have a role in bacterial virulence, the use of these systems as targets in the search of antivirulence compounds is also discussed. Finally, this review analyzes how the study of trade-offs associated with resistance acquisition mediated by efflux pumps' overexpression may guide strategies to tackle such resistance. EXPERT OPINION Increasing the knowledge of the regulation, structure and function of efflux pumps provides information for the rational design of RND efflux pump inhibitors. These inhibitors would increase bacterial susceptibility to several antibiotics and, occasionally, will reduce bacterial virulence. Furthermore, the information on the effect that efflux pumps' overexpression has on bacterial physiology may serve to develop new anti-resistance strategies.
Collapse
Affiliation(s)
- Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
- Department of Clinical Microbiology 9301, Rigshospitalet, Copenhagen, Denmark
| | | | | | | |
Collapse
|
14
|
Amieva R, Gil-Gil T, Martínez JL, Alcalde-Rico M. The MexJK Multidrug Efflux Pump Is Not Involved in Acquired or Intrinsic Antibiotic Resistance in Pseudomonas aeruginosa, but Modulates the Bacterial Quorum Sensing Response. Int J Mol Sci 2022; 23:7492. [PMID: 35886841 PMCID: PMC9323910 DOI: 10.3390/ijms23147492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/01/2022] [Accepted: 07/02/2022] [Indexed: 12/10/2022] Open
Abstract
Multidrug efflux pumps are critical elements in both intrinsic and acquired antibiotic resistance of bacterial populations. Consequently, most studies regarding these protein machineries focus on this specific phenotype. Nevertheless, different works show that efflux pumps participate in other aspects of bacterial physiology too. Herein, we study the Pseudomonas aeruginosa multidrug efflux pump MexJK. Previous studies, using model strains lacking MexAB-OprM and MexCD-OprJ efflux pumps, support that MexJK can extrude erythromycin, tetracycline, and triclosan. However, the results here reported indicate that this potential increased extrusion, in a mutant overexpressing mexJK, does not alter the antibiotics susceptibility in a wild-type genetic background where all intrinsic multidrug efflux pumps remain functional. Nevertheless, a clear impact on the quorum sensing (QS) response, mainly in the Pqs-dependent QS regulation network and in the expression of Pqs-regulated virulence factors, was observed linked to mexJK overexpression. The production of the siderophore pyoverdine strongly depended on the level of mexJK expression, suggesting that MexJK might participate in P. aeruginosa pyoverdine-dependent iron homeostasis. All in all, the results presented in the current article support that the functions of multidrug efflux pumps, as MexJK, go beyond antibiotic resistance and can modulate other relevant aspects of bacterial physiology.
Collapse
Affiliation(s)
- Rafael Amieva
- Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain; (R.A.); (T.G.-G.)
- SALUVET Group, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain; (R.A.); (T.G.-G.)
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - José Luis Martínez
- Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain; (R.A.); (T.G.-G.)
| | - Manuel Alcalde-Rico
- Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain; (R.A.); (T.G.-G.)
- Grupo de Resistencia Antimicrobiana en Bacterias Patógenas y Ambientales (GRABPA), Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
- Millennium Initiative for Collaborative Research on Bacterial Resistance (MICROB-R), Santiago 7550000, Chile
| |
Collapse
|
15
|
Gil-Gil T, Martínez JL. Glucose-6-phosphate Reduces Fosfomycin Activity Against Stenotrophomonas maltophilia. Front Microbiol 2022; 13:863635. [PMID: 35620111 PMCID: PMC9127766 DOI: 10.3389/fmicb.2022.863635] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/29/2022] [Indexed: 12/02/2022] Open
Abstract
It is generally accepted that fosfomycin activity is higher in the presence of glucose-6-phosphate, since its inducible transporter UhpT is one of the gates for fosfomycin entry. Accordingly, fosfomycin susceptibility tests are performed in the presence of this sugar; however, since Stenotrophomonas maltophilia lacks UhpT, it is doubtful that glucose-6-phosphate might be a fosfomycin adjuvant in this microorganism. The aim of the work was to determine whether glucose-6-phosphate or other metabolites may alter the activity of fosfomycin against S. maltophilia. To that goal, checkerboard assays were performed to analyze the synergy and antagonism of compounds, such as glucose-6-phosphate, fructose, phosphoenolpyruvate, and glyceraldehyde-3-phosphate, among others, with fosfomycin. Besides, minimal inhibitory concentrations of fosfomycin against a set of clinical S. maltophilia isolates presenting different levels of expression of the SmeDEF efflux pump were determined in the presence and absence of said compounds. Finally, intracellular fosfomycin concentrations were determined using a bioassay. Our results show that, opposite to what has been described for other bacteria, glucose-6-phosphate does not increase fosfomycin activity against S. maltophilia; it is a fosfomycin antagonist. However, other metabolites such as fructose, phosphoenolpyruvate and glyceraldehyde-3-phosphate, increase fosfomycin activity. Consistent with these results, glucose-6-phosphate decreases fosfomycin internalization (a feature against current ideas in the field), while the other three compounds increase the intracellular concentration of this antibiotic. These results support that current standard fosfomycin susceptibility tests made in the presence of glucose-6-phosphate do not account for the actual susceptibility to this antibiotic of some bacteria, such as S. maltophilia. Finally, the innocuous metabolites that increase S. maltophilia susceptibility to fosfomycin found in this work are potential adjuvants, which might be included in fosfomycin formulations used for treating infections by this resistant pathogen.
Collapse
Affiliation(s)
- Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain.,Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madri, Madrid, Spain
| | | |
Collapse
|
16
|
Laborda P, Sanz-García F, Ochoa-Sánchez LE, Gil-Gil T, Hernando-Amado S, Martínez JL. Wildlife and Antibiotic Resistance. Front Cell Infect Microbiol 2022; 12:873989. [PMID: 35646736 PMCID: PMC9130706 DOI: 10.3389/fcimb.2022.873989] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/14/2022] [Indexed: 11/27/2022] Open
Abstract
Antibiotic resistance is a major human health problem. While health care facilities are main contributors to the emergence, evolution and spread of antibiotic resistance, other ecosystems are involved in such dissemination. Wastewater, farm animals and pets have been considered important contributors to the development of antibiotic resistance. Herein, we review the impact of wildlife in such problem. Current evidence supports that the presence of antibiotic resistance genes and/or antibiotic resistant bacteria in wild animals is a sign of anthropic pollution more than of selection of resistance. However, once antibiotic resistance is present in the wild, wildlife can contribute to its transmission across different ecosystems. Further, the finding that antibiotic resistance genes, currently causing problems at hospitals, might spread through horizontal gene transfer among the bacteria present in the microbiomes of ubiquitous animals as cockroaches, fleas or rats, supports the possibility that these organisms might be bioreactors for the horizontal transfer of antibiotic resistance genes among human pathogens. The contribution of wildlife in the spread of antibiotic resistance among different hosts and ecosystems occurs at two levels. Firstly, in the case of non-migrating animals, the transfer will take place locally; a One Health problem. Paradigmatic examples are the above mentioned animals that cohabit with humans and can be reservoirs and vehicles for antibiotic resistance dissemination. Secondly, migrating animals, such as gulls, fishes or turtles may participate in the dissemination of antibiotic resistance across different geographic areas, even between different continents, which constitutes a Global Health issue.
Collapse
Affiliation(s)
- Pablo Laborda
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, Madrid, Spain
| | - Fernando Sanz-García
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, Zaragoza, Spain
| | - Luz Edith Ochoa-Sánchez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Teresa Gil-Gil
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, Madrid, Spain
| | - Sara Hernando-Amado
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - José Luis Martínez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- *Correspondence: José Luis Martínez,
| |
Collapse
|
17
|
Mart JL, Sanz-García F, Laborda P, Gil-Gil T, Ochoa-Sánchez LE, Hernando-Amado S. Emergence of intrinsically resistant Gram-negative bacteria with an environmental primary habitat. Int J Antimicrob Agents 2021. [DOI: 10.1016/j.ijantimicag.2021.106420.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
Sanz-García F, Gil-Gil T, Laborda P, Ochoa-Sánchez LE, Martínez JL, Hernando-Amado S. Coming from the Wild: Multidrug Resistant Opportunistic Pathogens Presenting a Primary, Not Human-Linked, Environmental Habitat. Int J Mol Sci 2021; 22:8080. [PMID: 34360847 PMCID: PMC8347278 DOI: 10.3390/ijms22158080] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/22/2021] [Accepted: 07/24/2021] [Indexed: 12/24/2022] Open
Abstract
The use and misuse of antibiotics have made antibiotic-resistant bacteria widespread nowadays, constituting one of the most relevant challenges for human health at present. Among these bacteria, opportunistic pathogens with an environmental, non-clinical, primary habitat stand as an increasing matter of concern at hospitals. These organisms usually present low susceptibility to antibiotics currently used for therapy. They are also proficient in acquiring increased resistance levels, a situation that limits the therapeutic options for treating the infections they cause. In this article, we analyse the most predominant opportunistic pathogens with an environmental origin, focusing on the mechanisms of antibiotic resistance they present. Further, we discuss the functions, beyond antibiotic resistance, that these determinants may have in the natural ecosystems that these bacteria usually colonize. Given the capacity of these organisms for colonizing different habitats, from clinical settings to natural environments, and for infecting different hosts, from plants to humans, deciphering their population structure, their mechanisms of resistance and the role that these mechanisms may play in natural ecosystems is of relevance for understanding the dissemination of antibiotic resistance under a One-Health point of view.
Collapse
Affiliation(s)
| | | | | | | | - José L. Martínez
- Centro Nacional de Biotecnología, CSIC, 28049 Madrid, Spain; (F.S.-G.); (T.G.-G.); (P.L.); (L.E.O.-S.); (S.H.-A.)
| | | |
Collapse
|
19
|
Gil-Gil T, Ochoa-Sánchez LE, Baquero F, Martínez JL. Antibiotic resistance: Time of synthesis in a post-genomic age. Comput Struct Biotechnol J 2021; 19:3110-3124. [PMID: 34141134 PMCID: PMC8181582 DOI: 10.1016/j.csbj.2021.05.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/13/2021] [Accepted: 05/20/2021] [Indexed: 12/20/2022] Open
Abstract
Antibiotic resistance has been highlighted by international organizations, including World Health Organization, World Bank and United Nations, as one of the most relevant global health problems. Classical approaches to study this problem have focused in infected humans, mainly at hospitals. Nevertheless, antibiotic resistance can expand through different ecosystems and geographical allocations, hence constituting a One-Health, Global-Health problem, requiring specific integrative analytic tools. Antibiotic resistance evolution and transmission are multilayer, hierarchically organized processes with several elements (from genes to the whole microbiome) involved. However, their study has been traditionally gene-centric, each element independently studied. The development of robust-economically affordable whole genome sequencing approaches, as well as other -omic techniques as transcriptomics and proteomics, is changing this panorama. These technologies allow the description of a system, either a cell or a microbiome as a whole, overcoming the problems associated with gene-centric approaches. We are currently at the time of combining the information derived from -omic studies to have a more holistic view of the evolution and spread of antibiotic resistance. This synthesis process requires the accurate integration of -omic information into computational models that serve to analyse the causes and the consequences of acquiring AR, fed by curated databases capable of identifying the elements involved in the acquisition of resistance. In this review, we analyse the capacities and drawbacks of the tools that are currently in use for the global analysis of AR, aiming to identify the more useful targets for effective corrective interventions.
Collapse
Affiliation(s)
- Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain
| | | | - Fernando Baquero
- Department of Microbiology, Hospital Universitario Ramón y Cajal (IRYCIS), Madrid, Spain
- CIBER en Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain
| | | |
Collapse
|
20
|
Gil-Gil T, Corona F, Martínez JL, Bernardini A. The Inactivation of Enzymes Belonging to the Central Carbon Metabolism Is a Novel Mechanism of Developing Antibiotic Resistance. mSystems 2020; 5:e00282-20. [PMID: 32487742 PMCID: PMC8534728 DOI: 10.1128/msystems.00282-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/14/2020] [Indexed: 11/20/2022] Open
Abstract
Fosfomycin is a bactericidal antibiotic, analogous to phosphoenolpyruvate, that exerts its activity by inhibiting the activity of MurA. This enzyme catalyzes the first step of peptidoglycan biosynthesis, the transfer of enolpyruvate from phosphoenolpyruvate to uridine-diphosphate-N-acetylglucosamine. Fosfomycin is increasingly being used, mainly for treating infections caused by Gram-negative multidrug-resistant bacteria. The mechanisms of mutational resistance to fosfomycin in Stenotrophomonas maltophilia, an opportunistic pathogen characterized by its low susceptibility to commonly used antibiotics, were studied in the current work. None of the mechanisms reported so far for other organisms, which include the production of fosfomycin-inactivating enzymes, target modification, induction of an alternative peptidoglycan biosynthesis pathway, and the impaired entry of the antibiotic, are involved in the acquisition of such resistance by this bacterial species. Instead, the unique cause of resistance in the mutants studied is the mutational inactivation of different enzymes belonging to the Embden-Meyerhof-Parnas central metabolism pathway. The amount of intracellular fosfomycin accumulation did not change in any of these mutants, showing that neither inactivation nor transport of the antibiotic is involved. Transcriptomic analysis also showed that the mutants did not present changes in the expression level of putative alternative peptidoglycan biosynthesis pathway genes or any related enzyme. Finally, the mutants did not present an increased phosphoenolpyruvate concentration that might compete with fosfomycin for its binding to MurA. On the basis of these results, we describe a completely novel mechanism of antibiotic resistance based on mutations of genes encoding metabolic enzymes.IMPORTANCE Antibiotic resistance has been largely considered a specific bacterial response to an antibiotic challenge. Indeed, its study has been mainly concentrated on mechanisms that affect the antibiotics (mutations in transporters, efflux pumps, and antibiotic-modifying enzymes, or their regulators) or their targets (i.e., target mutations, protection, or bypass). Usually, antibiotic resistance-associated metabolic changes were considered a consequence (fitness costs) and not a cause of antibiotic resistance. Herein, we show that alterations in the central carbon bacterial metabolism can also be the cause of antibiotic resistance. In the study presented here, Stenotrophomonas maltophilia acquires fosfomycin resistance through the inactivation of glycolytic enzymes belonging to the Embden-Meyerhof-Parnas pathway. Besides resistance to fosfomycin, this inactivation also impairs the bacterial gluconeogenic pathway. Together with previous work showing that antibiotic resistance can be under metabolic control, our results provide evidence that antibiotic resistance is intertwined with the bacterial metabolism.
Collapse
|
21
|
Gil-Gil T, Laborda P, Sanz-García F, Hernando-Amado S, Blanco P, Martínez JL. Antimicrobial resistance: A multifaceted problem with multipronged solutions. Microbiologyopen 2020; 8:e945. [PMID: 31724836 PMCID: PMC6855134 DOI: 10.1002/mbo3.945] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 09/19/2019] [Indexed: 12/12/2022] Open
Abstract
Infectious diseases still stand as a major cause of morbidity and mortality, and this problem can be worsened with the current antimicrobial resistance crisis. To tackle this crisis more studies analyzing the causes, routes, and reservoirs where antimicrobial resistance can emerge and expand, together with new antimicrobials and strategies for fighting antimicrobial resistance are needed. In the current special issue of MicrobiologyOpen, a set of articles dealing with the multiple faces of antimicrobial resistance are presented. These articles provide new information for understanding and addressing this problem.
Collapse
Affiliation(s)
| | - Pablo Laborda
- Centro Nacional de Biotecnología CSIC, Madrid, Spain
| | | | | | - Paula Blanco
- Centro Nacional de Biotecnología CSIC, Madrid, Spain
| | | |
Collapse
|
22
|
Hernando-Amado S, Alcalde-Rico M, Gil-Gil T, Valverde JR, Martínez JL. Naringenin Inhibition of the Pseudomonas aeruginosa Quorum Sensing Response Is Based on Its Time-Dependent Competition With N-(3-Oxo-dodecanoyl)-L-homoserine Lactone for LasR Binding. Front Mol Biosci 2020; 7:25. [PMID: 32181260 PMCID: PMC7059128 DOI: 10.3389/fmolb.2020.00025] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/07/2020] [Indexed: 12/23/2022] Open
Abstract
Bacterial quorum sensing (QS) is a cell-to-cell communication system that governs the expression of a large set of genes involved in bacterial-host interactions, including the production of virulence factors. Conversely, the hosts can produce anti-QS compounds to impair virulence of bacterial pathogens. One of these inhibitors is the plant flavonoid naringenin, which impairs the production of QS-regulated Pseudomonas aeruginosa virulence factors. In the present work, we analyze the molecular basis for such inhibition. Our data indicate that naringenin produces its effect by directly binding the QS regulator LasR, hence competing with its physiological activator, N-(3-oxo-dodecanoyl)-L-homoserine lactone (3OC12-HSL). The in vitro analysis of LasR binding to its cognate target DNA showed that the capacity of naringenin to outcompete 3OC12-HSL, when the latter is previously bound to LasR, is low. By using an E. coli LasR-based biosensor strain, which does not produce 3OC12-HSL, we determined that the inhibition of LasR is more efficient when naringenin binds to nascent LasR than when this regulator is already activated through 3OC12-HSL binding. According to these findings, at early exponential growth phase, when the amount of 3OC12-HSL is low, naringenin should proficiently inhibit the P. aeruginosa QS response, whereas at later stages of growth, once 3OC12-HSL concentration reaches a threshold enough for binding LasR, naringenin would not efficiently inhibit the QS response. To test this hypothesis, we analyze the potential effect of naringenin over the QS response by adding naringenin to P. aeruginosa cultures at either time zero (early inhibition) or at stationary growth phase (late inhibition). In early inhibitory conditions, naringenin inhibited the expression of QS-regulated genes, as well as the production of the QS-regulated virulence factors, pyocyanin and elastase. Nevertheless, in late inhibitory conditions, the P. aeruginosa QS response was not inhibited by naringenin. Therefore, this time-dependent inhibition may compromise the efficiency of this flavonoid, which will be effective just when used against bacterial populations presenting low cellular densities, and highlight the importance of searching for QS inhibitors whose mechanism of action does not depend on the QS status of the population.
Collapse
Affiliation(s)
- Sara Hernando-Amado
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Manuel Alcalde-Rico
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Millennium Nucleus for Collaborative Research on Bacterial Resistance, Valparaíso, Chile
| | - Teresa Gil-Gil
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - José R. Valverde
- Servicio de Computación Científica, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - José L. Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| |
Collapse
|
23
|
Gil-Gil T, Martínez JL, Blanco P. Mechanisms of antimicrobial resistance in Stenotrophomonas maltophilia: a review of current knowledge. Expert Rev Anti Infect Ther 2020; 18:335-347. [PMID: 32052662 DOI: 10.1080/14787210.2020.1730178] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Stenotrophomonas maltophilia is a prototype of bacteria intrinsically resistant to antibiotics. The reduced susceptibility of this microorganism to antimicrobials mainly relies on the presence in its chromosome of genes encoding efflux pumps and antibiotic inactivating enzymes. Consequently, the therapeutic options for treating S. maltophilia infections are limited.Areas covered: Known mechanisms of intrinsic, acquired and phenotypic resistance to antibiotics of S. maltophilia and the consequences of such resistance for treating S. maltophilia infections are discussed. Acquisition of some genes, mainly those involved in co-trimoxazole resistance, contributes to acquired resistance. Mutation, mainly in the regulators of chromosomally-encoded antibiotic resistance genes, is a major cause for S. maltophilia acquisition of resistance. The expression of some of these genes is triggered by specific signals or stressors, which can lead to transient phenotypic resistance.Expert opinion: Treatment of S. maltophilia infections is difficult because this organism presents low susceptibility to antibiotics. Besides, it can acquire resistance to antimicrobials currently in use. Particularly problematic is the selection of mutants overexpressing efflux pumps since they present a multidrug resistance phenotype. The use of novel antimicrobials alone or in combination, together with the development of efflux pumps' inhibitors may help in fighting S. maltophilia infections.
Collapse
Affiliation(s)
| | | | - Paula Blanco
- Molecular Basis of Adaptation Laboratory, Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| |
Collapse
|