scholarly journals The Antibiotic Fosfomycin Mimics the Effects of the Intermediate Metabolites Phosphoenolpyruvate and Glyceraldehyde-3-Phosphate on the Stenotrophomonas maltophilia Transcriptome

2021 ◽  
Vol 23 (1) ◽  
pp. 159
Author(s):  
Teresa Gil-Gil ◽  
Luz Edith Ochoa-Sánchez ◽  
José Luis Martínez
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Efflux Pump ◽  
Wall Stress ◽  
Large Degree ◽  
Opportunistic Pathogen ◽  
Central Carbon Metabolism ◽  
Intrinsic Resistance ◽  
One Step ◽  
Fosfomycin Resistance ◽  
Transcriptomic Changes

Stenotrophomonas maltophilia is an opportunistic pathogen with an environmental origin, which presents a characteristically low susceptibility to antibiotics and is capable of acquiring increased levels of resistance to antimicrobials. Among these, fosfomycin resistance seems particularly intriguing; resistance to this antibiotic is generally due to the activity of fosfomycin-inactivating enzymes, or to defects in the expression or the activity of fosfomycin transporters. In contrast, we previously described that the cause of fosfomycin resistance in S. maltophilia was the inactivation of enzymes belonging to its central carbon metabolism. To go one step further, here we studied the effects of fosfomycin on the transcriptome of S. maltophilia compared to those of phosphoenolpyruvate—its structural homolog—and glyceraldehyde-3-phosphate—an intermediate metabolite of the mutated route in fosfomycin-resistant mutants—. Our results show that transcriptomic changes present a large degree of overlap, including the activation of the cell-wall-stress stimulon. These results indicate that fosfomycin activity and resistance are interlinked with bacterial metabolism. Furthermore, we found that the studied compounds inhibit the expression of the smeYZ efflux pump, which confers intrinsic resistance to aminoglycosides. This is the first description of efflux pump inhibitors that can be used as antibiotic adjuvants to counteract antibiotic resistance in S. maltophilia.

scholarly journals Pseudomonas aeruginosa Polynucleotide Phosphorylase Controls Tolerance to Aminoglycoside Antibiotics by Regulating the MexXY Multidrug Efflux Pump

2020 ◽  
Author(s):  
Zheng Fan ◽  
Xiaolei Pan ◽  
Dan Wang ◽  
Ronghao Chen ◽  
Tongtong Fu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Opportunistic Pathogen ◽  
Aminoglycoside Antibiotics ◽  
Polynucleotide Phosphorylase ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump ◽  
Fluoroquinolone Antibiotics

Pseudomonas aeruginosa is an opportunistic pathogen that shows high intrinsic resistance to a variety of antibiotics. The MexX-MexY-OprM efflux pump plays an important role in the bacterial resistance to aminoglycoside antibiotics. Polynucleotide phosphorylase (PNPase) is a highly conserved exonuclease that plays important roles in RNA processing and bacterial response to environmental stresses. Previously, we demonstrated that PNPase controls the tolerance to fluoroquinolone antibiotics by influencing the production of pyocin in P. aeruginosa. In this study, we found that mutation of the PNPase coding gene (pnp) in P. aeruginosa increases the bacterial tolerance to aminoglycoside antibiotics. We further demonstrate that upregulation of the mexXY genes is responsible for the increased tolerance in the pnp mutant. Furthermore, our experimental results revealed that PNPase controls translation of the armZ mRNA through its 5′ untranslated region (5′-UTR). ArmZ had previously been shown to positively regulate the expression of mexXY. Therefore, our results revealed a novel role of PNPase in the regulation of armZ and subsequently the MexXY efflux pump.

scholarly journals Temperature, pH and Trimethoprim-Sulfamethoxazole Are Potent Inhibitors of Biofilm Formation by Stenotrophomonas maltophilia Clinical Isolates

2017 ◽  
Vol 66 (4) ◽  
pp. 433-438 ◽  
Author(s):  
Marjan Biočanin ◽  
Haowa Madi ◽  
Zorica Vasiljević ◽  
Milan Kojić ◽  
Branko Jovčić ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Stenotrophomonas Maltophilia ◽  
Tertiary Care ◽  
Opportunistic Pathogen ◽  
Growth Conditions ◽  
Clinical Isolates ◽  
Multiple Drug ◽  
Dependent Manner ◽  
Virulence Determinants ◽  
Intrinsic Resistance

Stenotrophomonas maltophilia, an opportunistic pathogen usually connected with healthcare-associated infections, is an environmental bacterium. Intrinsic resistance to multiple antibiotics, with different virulence determinants in the last decade classified this bacterium in the group of global multiple drug resistant (MDR) organism. S. maltophilia clinical isolates, were collected from tertiary care pediatric hospital in Belgrade, Serbia to investigate influence of different factors on biofilm formation, kinetics of biofilm formation for strong biofilm producers and effect of trimethoprim-sulfamethoxazole (TMP/SMX) on formed biofilm. Most of the isolates (89.8%) were able to form a biofilm. Analysis of biofilm formation in different growth conditions showed that changing of temeperature and pH had the stronggest effect on biofilm formation almost equally in group of cystic fibrosis (CF) and non-CF strains. TMP/SMX in concentration of 50 μg/ml reduced completely 24 h old biofilms while concentration of 25 μg/ml effects formed biofilms in a strain dependent manner. Among strains able to form strong biofilm CF isolates formed biofilm slower than non-CF isolates, while shaking conditions did not affect biofilm formation. Swimming motility was detected in both CF and non-CF isolates, however more motile strain formed stronger biofilms. This study suggests that temperature, pH and TMP/SMX had the strongest influence on biofilm formation in analyzed collection of S. maltophilia. A positive correlation between motility and strength of formed biofilm was demonstrated.

Mechanisms and phenotypic consequences of acquisition of tigecycline resistance by Stenotrophomonas maltophilia

2019 ◽  
Vol 74 (11) ◽  
pp. 3221-3230 ◽  
Author(s):  
Paula Blanco ◽  
Fernando Corona ◽  
José Luis Martinez
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Efflux Pump ◽  
Maximum Growth ◽  
Opportunistic Pathogen ◽  
Resistance Mechanisms ◽  
Fitness Cost ◽  
Negative Regulator ◽  
Cross Resistance ◽  
Bacterial Fitness ◽  
High Level

Abstract Objectives To elucidate the potential mutation-driven mechanisms involved in the acquisition of tigecycline resistance by the opportunistic pathogen Stenotrophomonas maltophilia. The mutational trajectories and their effects on bacterial fitness, as well as cross-resistance and/or collateral susceptibility to other antibiotics, were also addressed. Methods S. maltophilia populations were submitted to experimental evolution in the presence of increasing concentrations of tigecycline for 30 days. The genetic mechanisms involved in the acquisition of tigecycline resistance were determined by WGS. Resistance was evaluated by performing MIC assays. Fitness of the evolved populations and individual clones was assessed by measurement of the maximum growth rates. Results All the tigecycline-evolved populations attained high-level resistance to tigecycline following different mutational trajectories, yet with some common elements. Among the mechanisms involved in low susceptibility to tigecycline, mutations in the SmeDEF efflux pump negative regulator smeT, changes in proteins involved in the biogenesis of the ribosome and modifications in the LPS biosynthesis pathway seem to play a major role. Besides tigecycline resistance, the evolved populations presented cross-resistance to other antibiotics, such as aztreonam and quinolones, and they were hypersusceptible to fosfomycin, suggesting a possible combination treatment. Further, we found that the selected resistance mechanisms impose a relevant fitness cost when bacteria grow in the absence of antibiotic. Conclusions Mutational resistance to tigecycline was easily selected during exposure to this antibiotic. However, the fitness cost may compromise the maintenance of S. maltophilia tigecycline-resistant populations in the absence of antibiotic.

scholarly journals The Inactivation of Intrinsic Antibiotic Resistance Determinants Widens the Mutant Selection Window for Quinolones in Stenotrophomonas maltophilia

2012 ◽  
Vol 56 (12) ◽  
pp. 6397-6399 ◽  
Author(s):  
Guillermo García-León ◽  
María B. Sánchez ◽  
José L. Martínez
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Wild Type Strain ◽  
Efflux Pump ◽  
Intrinsic Resistance ◽  
Mutant Selection ◽  
Content Type ◽  
Resistance Determinants ◽  
Selection Window ◽  
Resistance Protein ◽  
Resistant Mutants

ABSTRACTWe have determined that the mutational inactivation of the SmeDEF efflux pump and the SmQnr quinolone resistance protein widens the mutant selection windows for ofloxacin and ciprofloxacin ofStenotrophomonas maltophiliaby reducing their MICs. Resistant mutants arising from a strain lacking SmeDEF and SmQnr presented levels of susceptibility similar to those of the wild-type strain. This indicates that inactivation of intrinsic resistance determinants might increase the chances for selecting resistant mutants at low antibiotic concentrations.

scholarly journals The multidrug resistance efflux pump MexCD-OprJ is a switcher of thePseudomonas aeruginosaquorum sensing response

2018 ◽  
Author(s):  
Manuel Alcalde-Rico ◽  
Jorge Olivares-Pacheco ◽  
Carolina Alvarez-Ortega ◽  
Miguel Cámara ◽  
José Luis Martínez
Keyword(s):  
Antibiotic Resistance ◽  
Efflux Pump ◽  
Antibiotic Resistance Genes ◽  
Opportunistic Pathogen ◽  
Point Of View ◽  
Signal Molecules ◽  
Human Pathogens ◽  
Chronic Infections ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump

AbstractMost antibiotic resistance genes acquired by human pathogens originate from environmental microorganisms. Therefore, understanding the additional functions of these genes, other than conferring antibiotic resistance, is relevant from an ecological point of view. We examined the effect that overexpression of the MexCD-OprJ multidrug efflux pump has in the physiology of the environmental opportunistic pathogenPseudomonas aeruginosa. Overexpression of this intrinsic resistance determinant shuts down theP. aeruginosaquorum sensing (QS) response. Impaired QS response is due to the extrusion of 4-hydroxy-2-heptylquinoline (HHQ), the precursor of thePseudomonasQuinolone Signal (PQS), leading to low PQS intracellular levels and reduced production of QS signal molecules. TheP. aeruginosaQS response induces the expression of hundreds of genes, which can be costly unless such activation becomes beneficial for the bacterial population. While it is known that the QS response is modulated by population density, information on additional signals/cues that may alert the cells about the benefits of mounting the response is still scarce. It is possible that MexCD-OprJ plays a role in this particular aspect; our results indicate that, upon overexpression, MexCD-OprJ can act as a switcher in the QS population response. If MexCD-OprJ alleviate the cost associated to trigger the QS response when un-needed, it could be possible that MexCD-OprJ overproducer strains might be eventually selected even in the absence of antibiotic selective pressure, acting as antibiotic resistant cheaters in heterogeneousP. aeruginosapopulations. This possibility may have potential implications for the treatment ofP. aeruginosachronic infections.

scholarly journals The inactivation of enzymes belonging to the central carbon metabolism, a novel mechanism of developing antibiotic resistance

2019 ◽  
Author(s):  
Teresa Gil-Gil ◽  
Fernando Corona ◽  
José Luis Martínez ◽  
Alejandra Bernardini
Keyword(s):  
Antibiotic Resistance ◽  
Stenotrophomonas Maltophilia ◽  
Bacterial Species ◽  
Opportunistic Pathogen ◽  
Central Carbon Metabolism ◽  
Bacterial Metabolism ◽  
Resistant Bacteria ◽  
Uridine Diphosphate ◽  
Biosynthesis Pathway ◽  
Peptidoglycan Biosynthesis

AbstractFosfomycin is a bactericidal antibiotic, analogous to phosphoenolpyruvate (PEP) that exerts its activity by inhibiting the activity of MurA. This enzyme catalyzes the first step of peptidoglycan biosynthesis, the transfer of enolpyruvate from PEP to uridine-diphosphate-N-acetylglucosamine. Fosfomycin is increasingly used in the last years, mainly for treating infections caused by Gram-negative multidrug resistant bacteria as Stenotrophomonas maltophilia, an opportunistic pathogen characterized by its low susceptibility to antibiotics of common use. The mechanisms of mutational resistance to fosfomycin in S. maltophilia were studied in the current work. None of the mechanisms so far described for other organisms, which include the production of fosfomycin inactivating enzymes, target modification, induction of alternative peptidoglycan biosynthesis pathway and the impaired entrance of the antibiotic, are involved in the acquisition of such resistance by this bacterial species. Rather the unique cause of resistance in the studied mutants 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 the inactivation nor the transport of the antibiotic were involved. Transcriptomic analysis also showed that the mutants did not present changes in the expression level of putative alternative peptidoglycan biosynthesis pathway genes neither any related enzyme. Finally, the mutants did not present an increased PEP concentration that might compete with fosfomycin for its binding to MurA. Based on these results, we describe a completely novel mechanism of antibiotic resistance based on the remodeling of S. maltophilia metabolism.SignificanceAntibiotic resistance (AR) has been largely considered as a specific bacterial response to an antibiotic challenge. Indeed, its study has been mainly concentrated in mechanisms that affect the antibiotics (mutations in transporters, the activity of efflux pumps and antibiotic modifying enzymes) or their targets (i.e.: target mutations, protection or bypass). Usually, AR-associated metabolic changes were considered to be a consequence (fitness costs) and not a cause of AR. Herein, we show that strong alterations in the bacterial metabolism can also be the cause of AR. In the study here presented, Stenotrophomonas maltophilia acquires fosfomycin resistance through the inactivation of glycolytic enzymes belonging to the Embden-Meyerhof-Parnas. Besides resistance to fosfomycin, this inactivation also impairs the bacterial gluconeogenic pathway. Together with previous work showing that AR can be under metabolic control, our results provide evidence that AR is intertwined with the bacterial metabolism.

mfsQ encoding an MFS efflux pump mediates adaptive protection of Stenotrophomonas maltophilia against benzalkonium chloride

2020 ◽  
Author(s):  
Jurairat Chittrakanwong ◽  
Nisanart Charoenlap ◽  
Skorn Mongkolsuk ◽  
Paiboon Vattanaviboon
Keyword(s):  
Benzalkonium Chloride ◽  
Stenotrophomonas Maltophilia ◽  
Efflux Pump ◽  
Opportunistic Pathogen ◽  
Major Facilitator Superfamily ◽  
Gene Encoding ◽  
Adaptive Resistance ◽  
Adaptive Protection ◽  
Hospital Environments ◽  
Major Facilitator

The persistence of Stenotrophomonas maltophilia, especially in hospital environments where disinfectants are used intensively, is one of the important factors that allow this opportunistic pathogen to establish nosocomial infections. In the present study, we illustrated that S. maltophilia possesses adaptive resistance to the disinfectant benzalkonium chloride (BAC). This BAC adaptation was abolished in the ΔmfsQ mutant, in which a gene encoding an efflux transporter belonging to the major facilitator superfamily (MFS) was deleted. The ΔmfsQ mutant also showed increased susceptibility to BAC and chlorhexidine gluconate relative to a parental wild type. The expression of mfsQ increased upon exposure to quaternary ammonium compounds, including BAC. Thus, the results of this study suggest that mfsQ plays a role in both adaptive and non-adaptive protection of S. maltophilia from the toxicity of the disinfectant BAC.

scholarly journals SmeDEF Multidrug Efflux Pump Contributes to Intrinsic Multidrug Resistance in Stenotrophomonas maltophilia

2001 ◽  
Vol 45 (12) ◽  
pp. 3497-3503 ◽  
Author(s):  
Li Zhang ◽  
Xian-Zhi Li ◽  
Keith Poole
Keyword(s):  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Stenotrophomonas Maltophilia ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump

ABSTRACT Stenotrophomonas maltophilia is an emerging nosocomial pathogen that displays high-level intrinsic resistance to a variety of structurally unrelated antimicrobial agents. Efflux mechanisms are known to contribute to acquired multidrug resistance in this organism, and indeed, one such multidrug efflux system, SmeDEF, was recently identified. Still, the importance of SmeDEF to intrinsic antibiotic resistance in S. maltophilia had not yet been determined. Reverse transcription-PCR confirmed expression of thesmeDEF genes in wild-type S. maltophilia, and deletion of smeE or smeF in wild-type strains rendered the mutants hypersusceptible to several antimicrobials, suggesting that SmeDEF contributes to intrinsic antimicrobial resistance in this organism. Expression of smeDEF was also enhanced in an in vitro-selected multidrug-resistant mutant, although deletion of smeF but not of smeE in these mutants compromised antimicrobial resistance. Apparently, hyperexpressed SmeF is capable of functioning with additional multidrug efflux components to promote multidrug resistance in S. maltophilia.

scholarly journals The Genomic Basis of Rapid Adaptation to Antibiotic Combination Therapy in Pseudomonas aeruginosa

2020 ◽  
Author(s):  
Camilo Barbosa ◽  
Niels Mahrt ◽  
Julia Bunk ◽  
Matthias Graßer ◽  
Philip Rosenstiel ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Combination Therapy ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Regulatory Gene ◽  
Opportunistic Pathogen ◽  
Regulatory Function ◽  
Central Target ◽  
Resistance Evolution ◽  
Intergenic Regions

Abstract Combination therapy is a common antibiotic treatment strategy that aims at minimizing the risk of resistance evolution in several infectious diseases. Nonetheless, evidence supporting its efficacy against the nosocomial opportunistic pathogen Pseudomonas aeruginosa remains elusive. Identification of the possible evolutionary paths to resistance in multidrug environments can help to explain treatment outcome. For this purpose, we here performed whole-genome sequencing of 127 previously evolved populations of P. aeruginosa adapted to sublethal doses of distinct antibiotic combinations and corresponding single-drug treatments, and experimentally characterized several of the identified variants. We found that alterations in the regulation of efflux pumps are the most favored mechanism of resistance, regardless of the environment. Unexpectedly, we repeatedly identified intergenic variants in the adapted populations, often with no additional mutations and usually associated with genes involved in efflux pump expression, possibly indicating a regulatory function of the intergenic regions. The experimental analysis of these variants demonstrated that the intergenic changes caused similar increases in resistance against single and multidrug treatments as those seen for efflux regulatory gene mutants. Surprisingly, we could find no substantial fitness costs for a majority of these variants, most likely enhancing their competitiveness toward sensitive cells, even in antibiotic-free environments. We conclude that the regulation of efflux is a central target of antibiotic-mediated selection in P. aeruginosa and that, importantly, changes in intergenic regions may represent a usually neglected alternative process underlying bacterial resistance evolution, which clearly deserves further attention in the future.

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