Determinants of Intrinsic Aminoglycoside Resistance in Pseudomonas aeruginosa

Krahn, Thomas; Gilmour, C. M.; Tilak, Justin; Fraud, Sébastien; Kerr, Nicholas; Lau, Calvin Ho-Fung; Poole, Keith

doi:10.1128/aac.01446-12

Cited by 58 publications

(65 citation statements)

References 85 publications

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“…In addition to the mechanisms that traditionally have been attributed to intrinsic resistance of P. aeruginosa, such as low permeability, efficient detoxification by efflux pumps, and antibiotic inactivation enzymes, recent studies indicate that intrinsic antibiotic resistance should be considered as an emergent systemic property rather than a specific adaptation to the presence of antibiotics. 1,17,29 In this vein, the novel cell wall recycling route in Pseudomonas sp. 8 provides a rationale for intrinsic resistance to fosfomycin, that is, the consequence of a unique metabolic pathway of cell wall sugar recovery in this organisms.…”

Section: Discussionmentioning

confidence: 99%

Blocking Peptidoglycan Recycling in Pseudomonas aeruginosa Attenuates Intrinsic Resistance to Fosfomycin

Borisova

Gisin

Mayer

2014

Microbial Drug Resistance

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Gram-negative bacteria recycle as much as half of their cell wall per generation. Here we show that interference with cell wall recycling in Pseudomonas aeruginosa strains results in four-to eight-fold increased susceptibility to the antibiotic fosfomycin, pushing the minimal inhibitory concentration for strains PA14 and PA01 to therapeutically appropriate values of 2-4 and 8-16 mg/L, respectively. A newly discovered metabolic pathway that connects cell wall recycling with peptidoglycan de novo biosynthesis is responsible for the high intrinsic resistance of P. aeruginosa to fosfomycin. The pathway comprises an anomeric cell wall amino sugar kinase (AmgK) and an uridylyl transferase (MurU), which together convert N-acetylmuramic acid (MurNAc) through MurNAc a-1-phosphate to uridine diphosphate (UDP)-MurNAc, thereby bypassing the fosfomycinsensitive de novo synthesis of UDP-MurNAc. Thus, inhibition of peptidoglycan recycling can be applied as a new strategy for the combinatory therapy against multidrug-resistant P. aeruginosa strains.

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Section: Discussionmentioning

confidence: 99%

Blocking Peptidoglycan Recycling in Pseudomonas aeruginosa Attenuates Intrinsic Resistance to Fosfomycin

Borisova

Gisin

Mayer

2014

Microbial Drug Resistance

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“…Clinical isolates of Pseudomonas have been reported to display a high degree of phenotypic diversity (8)(9)(10), especially those isolated from antibiotic treated patients. As a result of its high adaptability (11) and intrinsic antibiotic resistance (12), infections caused by P. aeruginosa are, in many instances, difficult to eradicate and can become persistent or even chronic (10), earning this bacterium a reputation as a paradigm of bacterial resistance (13).…”

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confidence: 99%

Predation in Homogeneous and Heterogeneous Phage Environments Affects Virulence Determinants of Pseudomonas aeruginosa

Hosseinidoust

Tufenkji

Ven

2013

Appl Environ Microbiol

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bThe rise of bacterial variants in the presence of lytic phages has been one of the basic grounds for evolution studies. However, there are incongruent results among different studies investigating the effect of phage resistance acquisition on bacterial fitness and virulence. We used experimental evolution to generate three classes of Pseudomonas aeruginosa variants under selective pressure from two different homogeneous phage environments and one heterogeneous phage environment. The fitness and virulence determinants of the variants, such as growth, motility, biofilm formation, resistance to oxidative stress, and the production of siderophores and chromophores, changed significantly compared to the control. Variants with similar colony morphology that were developed through different phage treatments have different phenotypic traits. Also, mRNA transcription for genes associated with certain phenotypic traits changed significantly; however, sequencing did not reveal any point mutations in selected gene loci. Furthermore, the appearance of small colony variants and melanogenic variants and the increase in pyocyanin and pyoverdin production for some variants are believed to affect the virulence of the population. The knowledge gained from this study will fundamentally contribute to our understanding of the evolutionary dynamics of bacteria under phage selective pressure which is crucial to the efficient utilization of bacteriophages in medical contexts. Pseudomonas aeruginosa is a metabolically versatile gammaproteobacterium which inhabits terrestrial, aquatic, animal, human, and plant host-associated environments (1). This pathogen is endowed with a fairly large genome (2) containing genes for many different virulence factors and regulatory mechanisms, allowing it to adapt to hostile environments (3). Moreover, changing environmental conditions result in rapid diversification of P. aeruginosa genotype to produce a range of morphologically distinct phenotypic variants (4, 5) through processes such as phase variation (6) and adaptive mutations (7). This adaptability is believed to give the variants a selective advantage under unfavorable conditions. Clinical isolates of Pseudomonas have been reported to display a high degree of phenotypic diversity (8-10), especially those isolated from antibiotic treated patients. As a result of its high adaptability (11) and intrinsic antibiotic resistance (12), infections caused by P. aeruginosa are, in many instances, difficult to eradicate and can become persistent or even chronic (10), earning this bacterium a reputation as a paradigm of bacterial resistance (13).By selecting for phage resistance, bacteriophages have been identified as agents that can drive the emergence of P. aeruginosa variants due to the strong selective pressure that they exert on the host community (14, 15). At an estimated total of 10 31 , bacteriophages are the most abundant biological agent on earth (16) and, based on their prevalence and effects on prokaryotic communities, they can play a significan...

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“…Plasmid pEX18Tc and its derivatives were maintained in E. coli with 5 (in L broth) or 10 (on L agar) g/ml of tetracycline and selected in P. aeruginosa with 50 g/ml of tetracycline. A ⌬amgR derivative of CF lung isolate K2156 was engineered using the pEX18Tc::⌬amgR plasmid pCG005 (Table 1) and a previously described protocol (60). A RIF-resistant rpoB derivative of P. aeruginosa PAO1 strain K767, K3696, was selected by plating an overnight culture (100 l) on L agar containing 32 g/ml of RIF (2ϫ MIC) and picking a colony that grew up overnight at 37°C.…”

Section: Methodsmentioning

confidence: 99%

“…A previously described fluorometric assay (60), involving the membrane potential-sensitive dye bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC 4 [3]), was employed to measure the degree of cytoplasmic membrane depolarization promoted by AG treatment of P. aeruginosa and the impact of RIF on this. Briefly, early-logarithmic-phase (OD 600 ϭ 0.3 to 0.5) L broth subcultures of P. aeruginosa were treated with either of the AGs gentamicin (GEN; final concentration, 2 or 5 g/ml) and PAR (final concentration, 256 or 640 g/ml).…”

Section: Methodsmentioning

confidence: 99%

“…Still, there is little, if any, indication that these are effective in enhancing AG susceptibility in intact organisms, particularly AG-resistant strains. AMEs occur infrequently in CF lung isolates (53)(54)(55), however, where the AG-exporting (56) MexXYOprM multidrug efflux system (57,58) and the AmgRS two-component system (TCS) (59,60) that responds to and protects P. aeruginosa from the adverse effects of AG-generated membranedamaging aberrant polypeptides (60,61) are major determinants of AG resistance (6, 50, 62; K. Poole, H. Fetar, and M. G. Surette, unpublished data). Thus, AG potentiators that target these might be useful adjuvants for antipseudomonal therapy of CF lung infections.…”

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confidence: 99%

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Potentiation of Aminoglycoside Activity in Pseudomonas aeruginosa by Targeting the AmgRS Envelope Stress-Responsive Two-Component System

Poole

Gilmour

Farha

et al. 2016

Antimicrob Agents Chemother

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A screen for agents that potentiated the activity of paromomycin (PAR), a 4,5-linked aminoglycoside (AG), against wild-type Pseudomonas aeruginosa identified the RNA polymerase inhibitor rifampin (RIF). RIF potentiated additional 4,5-linked AGs, such as neomycin and ribostamycin, but not the clinically important 4,6-linked AGs amikacin and gentamicin. Potentiation was absent in a mutant lacking the AmgRS envelope stress response two-component system (TCS), which protects the organism from AG-generated membrane-damaging aberrant polypeptides and, thus, promotes AG resistance, an indication that RIF was acting via this TCS in potentiating 4,5-linked AG activity. Potentiation was also absent in a RIF-resistant RNA polymerase mutant, consistent with its potentiation of AG activity being dependent on RNA polymerase perturbation. PAR-inducible expression of the AmgRS-dependent genes htpX and yccA was reduced by RIF, suggesting that AG activation of this TCS was compromised by this agent. Still, RIF did not compromise the membrane-protective activity of AmgRS, an indication that it impacted some other function of this TCS. RIF potentiated the activities of 4,5-linked AGs against several AG-resistant clinical isolates, in two cases also potentiating the activity of the 4,6-linked AGs. These cases were, in one instance, explained by an observed AmgRS-dependent expression of the MexXY multidrug efflux system, which accommodates a range of AGs, with RIF targeting of AmgRS undermining mexXY expression and its promotion of resistance to 4,5-and 4,6-linked AGs. Given this link between AmgRS, MexXY expression, and pan-AG resistance in P. aeruginosa, RIF might be a useful adjuvant in the AG treatment of P. aeruginosa infections. P seudomonas aeruginosa is a common nosocomial pathogen (1) and a major cause of morbidity and mortality in patients with cystic fibrosis (CF) (2, 3). Treatment of P. aeruginosa infections is complicated by the organism's innate resistance to many antimicrobials, a product of its impressive intrinsic resistome (4) and its access to an array of acquired resistance mechanisms (5, 6), with difficult-to-treat multidrug-resistant (MDR) (7) and extremely drug-resistant (8, 9) P. aeruginosa organisms becoming increasingly common. In the face of this intrinsic and acquired multidrug resistance, the use of agents historically used less commonly owing to issues of toxicity (e.g., the polymyxins) (10, 11) and the use of drug combination therapy (12, 13) are increasingly promoted. Still, despite much in vitro evidence for synergistic drug combinations being effective against MDR P. aeruginosa (14-20), the clinical benefits of drug combinations are less obvious (13,21,22).Aminoglycosides (AGs) have a long history in the management of P. aeruginosa infections, particularly in the case of lung infections in patients with cystic fibrosis (23,24), and are often used in combination with ␤-lactams (25-27) owing to a well-established synergy between these two antimicrobial classes (18,20,(26)(27)(28)(29). ␤-Lactam synergy ...

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Determinants of Intrinsic Aminoglycoside Resistance in Pseudomonas aeruginosa

Cited by 58 publications

References 85 publications

Blocking Peptidoglycan Recycling in Pseudomonas aeruginosa Attenuates Intrinsic Resistance to Fosfomycin

Blocking Peptidoglycan Recycling in Pseudomonas aeruginosa Attenuates Intrinsic Resistance to Fosfomycin

Predation in Homogeneous and Heterogeneous Phage Environments Affects Virulence Determinants of Pseudomonas aeruginosa

Potentiation of Aminoglycoside Activity in Pseudomonas aeruginosa by Targeting the AmgRS Envelope Stress-Responsive Two-Component System

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