Proteolytic Queues at ClpXP Increase Antibiotic Tolerance

Deter, Heather S.; Abualrahi, Alawiah H.; Jadhav, Prajakta; Schweer, Elise K; Ogle, Curtis T.; Butzin, Nicholas C.

doi:10.1021/acssynbio.9b00358

Cited by 17 publications

(10 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, the sspB mutations probably influence ClpX-mediated degradation of several proteins and alter the expression of genes related to cellular stress. In agreement with our findings, ClpXP contributes to antibiotic tolerance and peptide resistance in different bacterial species (52,53). Extrusion of AMPs by an energy-dependent efflux system constitutes an important AMP resistance mechanism (54)(55)(56), and exposure to antibiotics and biocides can select for mutation-driven overexpression of efflux pumps in S. maltophilia (15,16,57).…”

Section: Discussionsupporting

confidence: 90%

Antimicrobial Peptide Exposure Selects for Resistant and Fit Stenotrophomonas maltophilia Mutants That Show Cross-Resistance to Antibiotics

Blanco

Hjort

Martínez

et al. 2020

mSphere

View full text Add to dashboard Cite

Antimicrobial peptides (AMPs) are essential components of the innate immune system and have been proposed as promising therapeutic agents against drug-resistant microbes. AMPs possess a rapid bactericidal mode of action and can interact with different targets, but bacteria can also avoid their effect through a variety of resistance mechanisms. Apart from hampering treatment by the AMP itself, or that by other antibiotics in the case of cross-resistance, AMP resistance might also confer cross-resistance to innate human peptides and impair the anti-infective capability of the human host. A better understanding of how resistance to AMPs is acquired and the genetic mechanisms involved is needed before using these compounds as therapeutic agents. Using experimental evolution and whole-genome sequencing, we determined the genetic causes and the effect of acquired de novo resistance to three different AMPs in the opportunistic pathogen Stenotrophomonas maltophilia, a bacterium that is intrinsically resistant to a wide range of antibiotics. Our results show that AMP exposure selects for high-level resistance, generally without any reduction in bacterial fitness, conferred by mutations in different genes encoding enzymes, transporters, transcriptional regulators, and other functions. Cross-resistance to AMPs and to other antibiotic classes not used for selection, as well as collateral sensitivity, was observed for many of the evolved populations. The relative ease by which high-level AMP resistance is acquired, combined with the occurrence of cross-resistance to conventional antibiotics and the maintained bacterial fitness of the analyzed mutants, highlights the need for careful studies of S. maltophilia resistance evolution to clinically valuable AMPs. IMPORTANCE Stenotrophomonas maltophilia is an increasingly relevant multidrug-resistant (MDR) bacterium found, for example, in people with cystic fibrosis and associated with other respiratory infections and underlying pathologies. The infections caused by this nosocomial pathogen are difficult to treat due to the intrinsic resistance of this bacterium against a broad number of antibiotics. Therefore, new treatment options are needed, and considering the growing interest in using AMPs as alternative therapeutic compounds and the restricted number of antibiotics active against S. maltophilia, we addressed the potential for development of AMP resistance, the genetic mechanisms involved, and the physiological effects that acquisition of AMP resistance has on this opportunistic pathogen.

show abstract

Section: Discussionsupporting

confidence: 90%

Antimicrobial Peptide Exposure Selects for Resistant and Fit Stenotrophomonas maltophilia Mutants That Show Cross-Resistance to Antibiotics

Blanco

Hjort

Martínez

et al. 2020

mSphere

View full text Add to dashboard Cite

show abstract

“…To that end, results revealed that ClpP protease is upregulated 2.3-fold within wild-type, as opposed to YhaK-mutant cells. ClpPX has been shown to affect antibiotic tolerance during stress conditions in other Gram-negative pathogens, such as E. coli [51]. Regardless of the molecular mechanism(s), taken together, these results suggest that YhaK is likely to contribute to A. baumannii's AEMR phenotype.…”

Section: Rna Sequencing Of Wild-type and Yhak-mutant Cells During Gro...mentioning

confidence: 88%

Genetic Determinants of Acinetobacter baumannii Serum-Associated Adaptive Efflux-Mediated Antibiotic Resistance

et al. 2023

View full text Add to dashboard Cite

Acinetobacter baumannii is a nosocomial pathogen of serious healthcare concern that is becoming increasingly difficult to treat due to antibiotic treatment failure. Recent studies have revealed that clinically defined antibiotic-susceptible strains upregulate the expression of a repertoire of putative drug efflux pumps during their growth under biologically relevant conditions, e.g., in human serum, resulting in efflux-associated resistance to physiologically achievable antibiotic levels within a patient. This phenomenon, termed Adaptive Efflux Mediated Resistance (AEMR), has been hypothesized to account for one mechanism by which antibiotic-susceptible A. baumannii fails to respond to antibiotic treatment. In the current study, we sought to identify genetic determinants that contribute to A. baumannii serum-associated AEMR by screening a transposon mutant library for members that display a loss of the AEMR phenotype. Results revealed that mutation of a putative pirin-like protein, YhaK, results in a loss of AEMR, a phenotype that could be complemented by a wild-type copy of the yhaK gene and was verified in a second strain background. Ethidium bromide efflux assays confirmed that the loss of AEMR phenotype due to pirin-like protein mutation correlated with reduced overarching efflux capacity. Further, flow cytometry and confocal microscopy measures of a fluorophore 7-(dimethylamino)-coumarin-4-acetic acid (DMACA)-tagged levofloxacin isomer, ofloxacin, further verified that YhaK mutation reduces AEMR-mediated antibiotic efflux. RNA-sequencing studies revealed that YhaK may be required for the expression of multiple efflux-associated systems, including MATE and ABC families of efflux pumps. Collectively, the data indicate that the A. baumannii YhaK pirin-like protein plays a role in modulating the organism’s adaptive efflux-mediated resistance phenotype.

show abstract

“…While competition for shared transcriptional/translational resources represents a major source of context-dependence [15,16], it is only one of many such sources. For instance, the limited availability of degradation machinery [88][89][90][91] and the spatial arrangement and orientation of compositional context [12] can result in crosstalk among otherwise unrelated genes. Similarly, metabolic burden can negatively impact cellular growth rate [15,18,84,92,93], although its extent depends on experimental conditions [94][95][96] and may only be transient as it often disappears after several generations of exponential growth [16,97].…”

Section: Discussionmentioning

confidence: 99%

Context-Dependent Stability and Robustness of Genetic Toggle Switches with Leaky Promoters

György

2021

Life

View full text Add to dashboard Cite

Multistable switches are ubiquitous building blocks in both systems and synthetic biology. Given their central role, it is thus imperative to understand how their fundamental properties depend not only on the tunable biophysical properties of the switches themselves, but also on their genetic context. To this end, we reveal in this article how these factors shape the essential characteristics of toggle switches implemented using leaky promoters such as their stability and robustness to noise, both at single-cell and population levels. In particular, our results expose the roles that competition for scarce transcriptional and translational resources, promoter leakiness, and cell-to-cell heterogeneity collectively play. For instance, the interplay between protein expression from leaky promoters and the associated cost of relying on shared cellular resources can give rise to tristable dynamics even in the absence of positive feedback. Similarly, we demonstrate that while promoter leakiness always acts against multistability, resource competition can be leveraged to counteract this undesirable phenomenon. Underpinned by a mechanistic model, our results thus enable the context-aware rational design of multistable genetic switches that are directly translatable to experimental considerations, and can be further leveraged during the synthesis of large-scale genetic systems using computer-aided biodesign automation platforms.

show abstract

Proteolytic Queues at ClpXP Increase Antibiotic Tolerance

Cited by 17 publications

References 83 publications

Antimicrobial Peptide Exposure Selects for Resistant and Fit Stenotrophomonas maltophilia Mutants That Show Cross-Resistance to Antibiotics

Antimicrobial Peptide Exposure Selects for Resistant and Fit Stenotrophomonas maltophilia Mutants That Show Cross-Resistance to Antibiotics

Genetic Determinants of Acinetobacter baumannii Serum-Associated Adaptive Efflux-Mediated Antibiotic Resistance

Context-Dependent Stability and Robustness of Genetic Toggle Switches with Leaky Promoters

Contact Info

Product

Resources

About