Mutations in NalC induce MexAB-OprM overexpression resulting in high level of aztreonam resistance in environmental isolates of<i>Pseudomonas aeruginosa</i>

Braz, Vânia Santos; Furlan, João Pedro Rueda; Fernandes, Ana Flávia Tonelli; Stehling, Eliana Guedes

doi:10.1093/femsle/fnw166

Cited by 44 publications

(42 citation statements)

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“…Several well established mutations include an 8-bp deletion in the mexT gene which leads to up-regulation of the MexEF-OprN efflux pump and down-regulation of the OprD porin, and consequently resistance to fluoroquinolones and imipenem; the T105A substitution in AmpC, which causes resistance to non-carbapenem β-lactams (28), and the T83I substitution in the so called quinolone resistance-determining region (QRDR) of GyrA, conferring quinolone resistance. Another genomic variation commonly found to cause resistance in many P. aeruginosa isolates is the non-synonymous mutations in the TetR transcriptional regulator NalC which often leads to aztreonam resistance (29). Three non-synonymous mutations, G71-E, E153-Q, S209-R, are identified in the nalC gene in PA154197 (Table 2).…”

Section: Resultsmentioning

confidence: 99%

A multidrug resistant clinical P. aeruginosa isolate in the MLST550 clonal complex: uncoupled quorum sensing modulates the interplay of virulence and resistance

Cao¹,

Xia²,

Li³

et al. 2018

Preprint

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22Pseudomonas aeruginosa is a prevalent and pernicious pathogen equipped with both extraordinary 23 capabilities to infect the host and to develop antimicrobials resistance (AMR). Monitoring the 24 emergence of AMR high risk clones and understanding the interplay of their pathogenicity and 25 antibiotic resistance is of paramount importance to avoid resistance dissemination and to control 26 P. aeruginosa infections. In this study, we report the identification of a multidrug resistant (MDR) 27 P. aeruginosa strain PA154197 isolated from a blood stream infection in Hong Kong. PA154197 28 belongs to a distinctive MLST550 clonal complex shared by two international P. aeruginosa 29 isolates VW0289 and AUS544. Comparative genome and transcriptome analysis with the 30 reference strain PAO1 led to the identification of a variety of genetic variations in antibiotic 31 resistance genes and the hyper-expression of three multidrug efflux pumps MexAB-OprM, 32 MexEF-OprN, and MexGHI-OpmD in PA154197. Unlike many resistant isolates displaying an 33 attenuated virulence, PA154197 produces a significantly high level of the P. aeruginosa major 34 virulence factor pyocyanin (PYO) and displays an uncompromised virulence compared to PAO1. 35 Further analysis revealed that the secondary quorum sensing system Pqs which primarily controls 36 the PYO production is hyper-active in PA154197 independent of the master QS systems Las and 37 Rhl. Together, these investigations disclose a unique, uncoupled QS mediated pathoadaptation 38 mechanism in clinical P. aeruginosa which may account for the high pathogenic potentials and 39 antibiotics resistance in the MDR isolate PA154197. 40 41 Pseudomonas aeruginosa is a ubiquitous Gram-negative pathogen that causes a variety of 42 notorious infections in humans such as ventilator-associated pneumonia, lung infections of cystic 43 fibrosis (CF) patients, burn wound infection, and various sepsis syndromes. It is the second leading 44 cause of hospital-acquired infections and is especially problematic in ICUs, where it is the leading 45 cause of pneumonia among pediatric patients and is responsible for a large number of urinary tract 46 (10% in US and 19% in Europe), blood stream (3% in US and 10% in Europe), eye, ear, nose, and47 throat infections (1-3). Compounding the burden of these infections is the extraordinary capability 48 of the pathogen to develop antibiotic and multidrug resistance (MDR) even during the course of 49 antibiotics therapy. P. aeruginosa is one of the "ESKAPE" (Enterococcus spp., Staphylococcus 50 aureus, Klebsiella spp., Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter 51 spp.) organisms which are recognized by the WHO as an alarming threat to the global public heath 52 associated with antimicrobial resistance (AMR). As a consequence, the diseases outcome of the P. 53 aeruginosa infections is the complex interplay of the pathogen (its pathogenicity and virulence), 54 hospital environments (antibiotic therapies and the emergence of AMR), and the patie...

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Section: Resultsmentioning

confidence: 99%

A multidrug resistant clinical P. aeruginosa isolate in the MLST550 clonal complex: uncoupled quorum sensing modulates the interplay of virulence and resistance

Cao¹,

Xia²,

Li³

et al. 2018

Preprint

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“…Expression of the mexAB-oprM operon is transcriptionally regulated by MexR, NalC and NalD [44]. Sequencing of these regulators and their corresponding upstream regions (500 bp) revealed wild type sequence for mexR and nalD , when compared to PA14.…”

Section: Resultsmentioning

confidence: 99%

Characterization of 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione resistance in pyomelanogenic Pseudomonas aeruginosa DKN343

Ketelboeter

Bardy

2017

PLoS ONE

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Pyomelanin is a reddish-brown pigment that provides bacteria and fungi protection from oxidative stress, and is reported to contribute to infection persistence. Production of this pigment can be inhibited by the anti-virulence agent 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC). The Pseudomonas aeruginosa clinical isolate DKN343 exhibited high levels of resistance to NTBC, and the mechanism of pyomelanin production in this strain was uncharacterized. We determined that pyomelanin production in the clinical Pseudomonas aeruginosa isolate DKN343 was due to a loss of function in homogentisate 1,2-dioxygenase (HmgA). Several potential resistance mechanisms were investigated, and the MexAB-OprM efflux pump is required for resistance to NTBC. DKN343 has a frameshift mutation in NalC, which is a known indirect repressor of the mexAB-oprM operon. This frameshift mutation may contribute to the increased resistance of DKN343 to NTBC. Additional studies investigating the prevalence of resistance in pyomelanogenic microbes are necessary to determine the future applications of NTBC as an anti-virulence therapy.

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“…Eleven of the mutants contained mutations in the porin-encoding oprD gene, with mutations in this gene representing a primary mechanism for carbapenem resistance (24,(37)(38)(39). Ten of the mutants had mutations in nalC, nalD or mexR, with mutations in these genes causing upregulation of the efflux pumps and being associated with β-lactam resistance (28,(40)(41)(42). Mutations in ftsI, that encodes the meropenem binding protein PBP3A, were present in 3 mutants consistent with the known role of such mutations in resistance (24,43).…”

Section: Meropenem-selected Mutantsmentioning

confidence: 99%

A large-scale comparison shows that genetic changes causing antibiotic resistance in experimentally evolvedPseudomonas aeruginosapredict those in naturally evolved bacteria

Wardell¹,

Rehman²,

Martin³

et al. 2019

Preprint

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Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of acute and chronic infections. An increasing number of isolates have acquired mutations that make them antibiotic resistant, making treatment more difficult. To identify resistance-associated mutations we experimentally evolved the antibiotic sensitive strain P. aeruginosa PAO1 to become resistant to three widely used anti-pseudomonal antibiotics, ciprofloxacin, meropenem and tobramycin. Mutants were able to tolerate up to 2048-fold higher concentrations of antibiotic than strain PAO1. Genome sequences were determined for thirteen mutants for each antibiotic. Each mutant had between 2 and 8 mutations. There were at least 8 genes mutated in more than one mutant per antibiotic, demonstrating the complexity of the genetic basis of resistance. Additionally, large deletions of up to 479kb arose in multiple meropenem resistant mutants. For all three antibiotics mutations arose in genes known to be associated with resistance, but also in genes not previously associated with resistance. To determine the clinical relevance of mutations uncovered in experimentallyevolved mutants we analysed the corresponding genes in 457 isolates of P. aeruginosa from patients with cystic fibrosis or bronchiectasis as well as 172 isolates from the general environment. Many of the genes identified through experimental evolution had changes predicted to be function-altering in clinical isolates but not in isolates from the general environment, showing that mutated genes in experimentally evolved bacteria can predict those that undergo mutation during infection. These findings expand understanding of the genetic basis of antibiotic resistance in P. aeruginosa as well as demonstrating the validity of experimental evolution in identifying clinically-relevant resistance-associated mutations.' ImportanceThe rise in antibiotic resistant bacteria represents an impending global health crisis. As such, understanding the genetic mechanisms underpinning this resistance can be a crucial piece of the puzzle to combatting it. The importance of this research is that by experimentally evolving P. aeruginosa to three clinically relevant antibiotics, we have generated a catalogue of genes that can contribute to resistance in vitro. We show that many (but not all) of these genes are clinically relevant, by identifying variants in clinical isolates of P. aeruginosa. This research furthers our understanding of the genetics leading to resistance in P. aeruginosa and provides tangible evidence that these genes can play a role clinically, potentially leading to new druggable targets or inform therapies.

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Mutations in NalC induce MexAB-OprM overexpression resulting in high level of aztreonam resistance in environmental isolates ofPseudomonas aeruginosa

Cited by 44 publications

References 29 publications

A multidrug resistant clinical P. aeruginosa isolate in the MLST550 clonal complex: uncoupled quorum sensing modulates the interplay of virulence and resistance

A multidrug resistant clinical P. aeruginosa isolate in the MLST550 clonal complex: uncoupled quorum sensing modulates the interplay of virulence and resistance

Characterization of 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione resistance in pyomelanogenic Pseudomonas aeruginosa DKN343

A large-scale comparison shows that genetic changes causing antibiotic resistance in experimentally evolvedPseudomonas aeruginosapredict those in naturally evolved bacteria

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