Multiple Mutations Lead to MexXY-OprM-Dependent Aminoglycoside Resistance in Clinical Strains of Pseudomonas aeruginosa

Guénard, Sophie; Muller, Cédric; Monlezun, Laura; Bénas, P.; Broutin, Isabelle; Jeannot, Katy; Plésiat, Patrick

doi:10.1128/aac.01252-13

Cited by 96 publications

(93 citation statements)

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“…Further, all of these isolates were resistant to at least 1 of the 3 aminoglycosides tested ( Table 1), antibiotics that are substrates of MexXY. Several mutations in mexZ have been reported that contribute to the overexpression of the MexXY pump (Llanes et al 2004;Quale et al 2006;Guénard et al 2014;Solé et al 2015). Mutations in mexZ have been shown to be common in chronic CF airway infections by P. aeruginosa (Smith et al 2006).…”

Section: Discussionmentioning

confidence: 99%

MexXY efflux pump overexpression and aminoglycoside resistance in cystic fibrosis isolates of Pseudomonas aeruginosa from chronic infections

et al. 2017

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Abstract:In this study, we analyzed 15 multidrug-resistant cystic fibrosis isolates of Pseudomonas aeruginosa from chronic lung infections for expression of 4 different multidrug efflux systems (MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY), using quantitative reverse transcriptase PCR. Overexpression of MexXY pump was observed in all of the isolates tested. Analysis of regulatory genes that control the expression of these 4 efflux pumps revealed a number of previously uncharacterized mutations. Our work shows that MexXY pump overexpression is common in cystic fibrosis isolates and could be contributing to their reduced aminoglycoside susceptibility. Further, we also identified novel mutations in the regulatory genes of the 4 abovementioned Resistance-Nodulation-Division superfamily pumps that may be involved in the overexpression of these pumps.Key words: aminoglycoside resistance, MexZ, regulatory gene mutations.Résumé : Dans cette étude, les auteurs ont analysé 15 isolats multirésistants de Pseudomonas aeruginosa prélevés de patients atteints de fibrose kystique et souffrant d'infections chroniques, relativement à l'expression de 4 systèmes d'efflux responsables de la multirésistance aux médicaments (MexAB-OprM, MexCD-OprJ, MexEF-OprN et MexXY), à l'aide de la RT-PCR quantitative. La surexpression de la pompe MexXY était observée chez tous les isolats testés. L'analyse de gènes régulateurs qui contrôlent l'expression de ces 4 pompes d'efflux a révélé un nombre de mutations encore jamais caractérisées. Leur travail montre que la surexpression de la pompe MexXY est fréquente chez les isolats de fibrose kystique et qu'elle pourrait contribuer à leur sensibilité réduite aux aminoglycosides. De plus, ils ont aussi identifié de nouvelles mutations à l'intérieur de gènes régulateurs des quatre pompes RND mentionnées plus haut qui pourraient être impliquées dans la surexpression des ces pompes. [Traduit par la Rédaction]Mots-clés : résistance aux aminoglycosides, MexZ, mutations de gènes régulateurs.

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Section: Discussionmentioning

confidence: 99%

MexXY efflux pump overexpression and aminoglycoside resistance in cystic fibrosis isolates of Pseudomonas aeruginosa from chronic infections

et al. 2017

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“…Finally, in the third group of mutants, named agrW2, mutational activation of the sensor ParS or the response regulator ParR of the two-component system ParRS leads to constitutive expression of the efflux operon (384,444). A detailed analysis of a collection of non-cystic fibrosis isolates showing moderate, nonenzymatic resistance to aminoglycosides demonstrated the occurrence of the three types of mutants (agrZ, agrW1, and agrW2) among clinical strains (452). In cystic fibrosis patients, the agrZ type seems to predominate over the other two (446)(447)(448).…”

Section: Pseudomonas Aeruginosamentioning

confidence: 99%

“…When activated by mutations or bacterial exposure to subinhibitory concentrations of polycationic agents such as polymyxins (833), this two-component system downregulates oprD expression with a concomitant upregulation of the transcript levels of mexXY(oprA) and the LPS modification operon arnBCADTEF-ugd (444). This coordinated response results in an MDR phenotype due to the complementary effects of drug efflux and reduced OM permeability (LPS modification and OprD loss) (444,452).…”

Section: P Aeruginosa Efflux Pumpsmentioning

confidence: 99%

“…In so-called agrZ mutants, the mexZ gene and its product are compromised by a number of nonspecific genetic events (e.g., indels and point mutations) (425, 439, 443, 446-448, 450, 457). In addition to mutations causing mexZ disruption, some generate single amino acid substitutions in the DNA-binding domain, the dimerization domain, or the structure of MexZ, abrogating its repressor activity (416,452,458,459). A second group of mutants, dubbed agrW1, was defined in line with various defects in ribosomal proteins such as L1 (436), L25 (460), L21 and L27 (461), or components of the Fmt bypass (methionyltRNA fMet formyltransferase FolD) (445) that ultimately affect protein synthesis.…”

Section: Pseudomonas Aeruginosamentioning

confidence: 99%

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The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

2015

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SUMMARY The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.

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“…These loci are known from the literature to be associated with the emergence of drug resistance in P. aeruginosa (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Hence, we became interested to know if and to what extent the global P. aeruginosa population in lungs of patients (CF lungs) carries mutations in these genes.…”

mentioning

confidence: 99%

Molecular Epidemiology of Mutations in Antimicrobial Resistance Loci of Pseudomonas aeruginosa Isolates from Airways of Cystic Fibrosis Patients

Greipel

Fischer

Klockgether

et al. 2016

Antimicrob Agents Chemother

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bThe chronic airway infections with Pseudomonas aeruginosa in people with cystic fibrosis (CF) are treated with aerosolized antibiotics, oral fluoroquinolones, and/or intravenous combination therapy with aminoglycosides and ␤-lactam antibiotics. An international strain collection of 361 P. aeruginosa isolates from 258 CF patients seen at 30 CF clinics was examined for mutations in 17 antimicrobial susceptibility and resistance loci that had been identified as hot spots of mutation by genome sequencing of serial isolates from a single CF clinic. Combinatorial amplicon sequencing of pooled PCR products identified 1,112 sequence variants that were not present in the genomes of representative strains of the 20 most common clones of the global P. aeruginosa population. A high frequency of singular coding variants was seen in spuE, mexA, gyrA, rpoB, fusA1, mexZ, mexY, oprD, ampD, parR, parS, and envZ (amgS), reflecting the pressure upon P. aeruginosa in lungs of CF patients to generate novel protein variants. The proportion of nonneutral amino acid exchanges was high. Of the 17 loci, mexA, mexZ, and pagL were most frequently affected by independent stop mutations. Private and de novo mutations seem to play a pivotal role in the response of P. aeruginosa populations to the antimicrobial load and the individual CF host. C ystic fibrosis (CF) is a severe autosomal recessive trait that is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) (1). CFTR dysfunction affects many organs, but lung disease is responsible for the vast majority of morbidity and mortality in people with CF. The basic defect in CF predisposes to viral and bacterial airway infections (2). The most prevalent airway pathogen in adolescents and adults with CF is Pseudomonas aeruginosa (3, 4). The chronic airway colonization with P. aeruginosa has been associated with a rapid decline in lung function, heightened lung inflammation, and worse prognosis (1).Antipseudomonal chemotherapy in CF comprises intravenous combination therapy with ␤-lactam antibiotics and aminoglycosides, oral fluoroquinolones, immunomodulatory treatment with azithromycin and aerosolized antibiotics such as tobramycin, aztreonam, or colistin (4-8). The high antimicrobial pressure exerted on the microorganism, which can persist and diversify in the patient's airways for decades, drives the emergence of drug resistance phenotypes (9, 10). Typical targets are elements of replication, transcription, and translation, the cell wall, and transport and its regulation (9-11).During ongoing studies on the long-term microevolution of P. aeruginosa in lungs of 12 CF patients, we have identified 17 loci to be repetitively hit by mutations. These loci are known from the literature to be associated with the emergence of drug resistance in P. aeruginosa (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Hence, we became interested to know if and to what extent the global P. aeruginosa population in lungs of patients (CF lungs) carries mutations in these ge...

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Multiple Mutations Lead to MexXY-OprM-Dependent Aminoglycoside Resistance in Clinical Strains of Pseudomonas aeruginosa

Cited by 96 publications

References 54 publications

MexXY efflux pump overexpression and aminoglycoside resistance in cystic fibrosis isolates of Pseudomonas aeruginosa from chronic infections

MexXY efflux pump overexpression and aminoglycoside resistance in cystic fibrosis isolates of Pseudomonas aeruginosa from chronic infections

The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

Molecular Epidemiology of Mutations in Antimicrobial Resistance Loci of Pseudomonas aeruginosa Isolates from Airways of Cystic Fibrosis Patients

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