Enhancement of antibiotic susceptibility ofStenotrophomonas maltophiliausing a polyclonal antibody developed against an ABC multidrug efflux pump

2011 ◽  
Vol 57 (10) ◽  
pp. 820-828 ◽  
Author(s):  
Arif Al-Hamad ◽  
James Burnie ◽  
Mathew Upton
Keyword(s):  
Polyclonal Antibody ◽  
Growth Kinetic ◽  
Efflux Pump ◽  
Kinetic Studies ◽  
Efflux Pumps ◽  
Clinical Strain ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump

Stenotrophomonas maltophilia is an emerging nosocomial pathogen capable of causing healthcare-associated infections, including pneumonia and bacteremia. Intrinsic resistance in S. maltophilia is exhibited towards many broad-spectrum antibiotics, and treatment recommendations are controversial. One of the major causes of antimicrobial resistance is attributed to a robust array of efflux pumps that extrude drug compounds from the cell. Using checkerboard and growth kinetic assays, we evaluated the in vitro activity of a polyclonal antibody raised against an ATP-binding cassette efflux protein in S. maltophilia. Six clinical strains of S. maltophilia and one type strain were challenged with co-trimoxazole, ticarcillin–clavulanate, and ciprofloxacin, alone and in combination with antibody. One clinical strain was tested by growth curve experiments for each antibiotic–antibody combination. The use of antibody resulted in significantly increased susceptibility in 71.4% (15/21) of treatments tested, with 33.3% displaying synergy and 38.1% an additive effect. In growth kinetic studies, synergy was obtained for each antibiotic–antibody combination. Thus, the use of antibody raised against multidrug efflux pumps for the treatment of multidrug-resistant organisms warrants further investigation. Antibody targeting substrate recognition sites, or other functionally important epitopes, may lead to inhibition of multiple efflux pumps that share the same substrate and is an attractive area that should be explored.

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 Prevalence, Development, and Molecular Mechanisms of Bacteriocin Resistance inCampylobacter

2011 ◽  
Vol 77 (7) ◽  
pp. 2309-2316 ◽  
Author(s):  
Ky Van Hoang ◽  
Norman J. Stern ◽  
Arnold M. Saxton ◽  
Fuzhou Xu ◽  
Ximin Zeng ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Acquired Resistance ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump ◽  
Major Step ◽  
On Farm ◽  
Level Resistance

ABSTRACTBacteriocins (BCNs) are antimicrobial peptides produced by bacteria with narrow or broad spectra of antimicrobial activity. Recently, several unique anti-CampylobacterBCNs have been identified from commensal bacteria isolated from chicken intestines. These BCNs dramatically reducedC. jejunicolonization in poultry and are being directed toward on-farm control ofCampylobacter. However, no information concerning prevalence, development, and mechanisms of BCN resistance inCampylobacterexists. In this study, susceptibilities of 137C. jejuniisolates and 20C. coliisolates to the anti-CampylobacterBCNs OR-7 and E-760 were examined. Only oneC. colistrain displayed resistance to the BCNs (MIC, 64 μg/ml), while others were susceptible, with MICs ranging from 0.25 to 4 μg/ml. TheC. colimutants resistant to BCN OR-7 also were obtained byin vitroselection, but all displayed only low-level resistance to OR-7 (MIC, 8 to 16 μg/ml). The acquired BCN resistance inC. colicould be transferred at intra- and interspecies levels amongCampylobacterstrains by biphasic natural transformation. Genomic examination of the OR-7-resistant mutants by using DNA microarray and random transposon mutagenesis revealed that the multidrug efflux pump CmeABC contributes to both intrinsic resistance and acquired resistance to the BCNs. Altogether, this study represents the first report of and a major step forward in understanding BCN resistance inCampylobacter, which will facilitate the development of effective BCN-based strategies to reduce theCampylobacterloads in poultry.

scholarly journals Molecular Insights into an Antibiotic Enhancer Action of New Morpholine-Containing 5-Arylideneimidazolones in the Fight against MDR Bacteria

2021 ◽  
Vol 22 (4) ◽  
pp. 2062
Author(s):  
Aneta Kaczor ◽  
Karolina Witek ◽  
Sabina Podlewska ◽  
Veronique Sinou ◽  
Joanna Czekajewska ◽  
...  
Keyword(s):  
Molecular Modelling ◽  
Efflux Pump ◽  
Gram Negative Bacteria ◽  
Potential Mechanism ◽  
Multidrug Efflux ◽  
Aromatic Rings ◽  
Allosteric Site ◽  
Multidrug Efflux Pump ◽  
Dual Action

In the search for an effective strategy to overcome antimicrobial resistance, a series of new morpholine-containing 5-arylideneimidazolones differing within either the amine moiety or at position five of imidazolones was explored as potential antibiotic adjuvants against Gram-positive and Gram-negative bacteria. Compounds (7–23) were tested for oxacillin adjuvant properties in the Methicillin-susceptible S. aureus (MSSA) strain ATCC 25923 and Methicillin-resistant S. aureus MRSA 19449. Compounds 14–16 were tested additionally in combination with various antibiotics. Molecular modelling was performed to assess potential mechanism of action. Microdilution and real-time efflux (RTE) assays were carried out in strains of K. aerogenes to determine the potential of compounds 7–23 to block the multidrug efflux pump AcrAB-TolC. Drug-like properties were determined experimentally. Two compounds (10, 15) containing non-condensed aromatic rings, significantly reduced oxacillin MICs in MRSA 19449, while 15 additionally enhanced the effectiveness of ampicillin. Results of molecular modelling confirmed the interaction with the allosteric site of PBP2a as a probable MDR-reversing mechanism. In RTE, the compounds inhibited AcrAB-TolC even to 90% (19). The 4-phenylbenzylidene derivative (15) demonstrated significant MDR-reversal “dual action” for β-lactam antibiotics in MRSA and inhibited AcrAB-TolC in K. aerogenes. 15 displayed also satisfied solubility and safety towards CYP3A4 in vitro.

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 CmeR Functions as a Pleiotropic Regulator and Is Required for Optimal Colonization of Campylobacter jejuni In Vivo

2008 ◽  
Vol 190 (6) ◽  
pp. 1879-1890 ◽  
Author(s):  
Baoqing Guo ◽  
Ying Wang ◽  
Feng Shi ◽  
Yi-Wen Barton ◽  
Paul Plummer ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Capsular Polysaccharide ◽  
Efflux Pump ◽  
Loss Of Function ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Reverse Transcription Pcr ◽  
Dicarboxylate Transport

ABSTRACT CmeR functions as a transcriptional repressor modulating the expression of the multidrug efflux pump CmeABC in Campylobacter jejuni. To determine if CmeR also regulates other genes in C. jejuni, we compared the transcriptome of the cmeR mutant with that of the wild-type strain using a DNA microarray. This comparison identified 28 genes that showed a ≥2-fold change in expression in the cmeR mutant. Independent real-time quantitative reverse transcription-PCR experiments confirmed 27 of the 28 differentially expressed genes. The CmeR-regulated genes encode membrane transporters, proteins involved in C4-dicarboxylate transport and utilization, enzymes for biosynthesis of capsular polysaccharide, and hypothetical proteins with unknown functions. Among the genes whose expression was upregulated in the cmeR mutant, Cj0561c (encoding a putative periplasmic protein) showed the greatest increase in expression. Subsequent experiments demonstrated that this gene is strongly repressed by CmeR. The presence of the known CmeR-binding site, an inverted repeat of TGTAAT, in the promoter region of Cj0561c suggests that CmeR directly inhibits the transcription of Cj0561c. Similar to expression of cmeABC, transcription of Cj0561c is strongly induced by bile compounds, which are normally present in the intestinal tracts of animals. Inactivation of Cj0561c did not affect the susceptibility of C. jejuni to antimicrobial compounds in vitro but reduced the fitness of C. jejuni in chickens. Loss-of-function mutation of cmeR severely reduced the ability of C. jejuni to colonize chickens. Together, these findings indicate that CmeR governs the expression of multiple genes with diverse functions and is required for Campylobacter adaptation in the chicken host.

scholarly journals Functional Cloning and Characterization of a Multidrug Efflux Pump, MexHI-OpmD, from a Pseudomonas aeruginosa Mutant

2003 ◽  
Vol 47 (9) ◽  
pp. 2990-2992 ◽  
Author(s):  
Hiroshi Sekiya ◽  
Takehiko Mima ◽  
Yuji Morita ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ethidium Bromide ◽  
Rhodamine 6G ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Efflux ◽  
Chromosomal Dna ◽  
Multidrug Efflux Pump ◽  
Multidrug Efflux Pumps

ABSTRACT We isolated mutant YM644, which showed elevated resistance to norfloxacin, ethidium bromide, acriflavine, and rhodamine 6G, from Pseudomonas aeruginosa YM64, a strain that lacks four major multidrug efflux pumps. The genes responsible for the resistance were mexHI-opmD. Elevated ethidium extrusion was observed with cells of YM644 and YM64 harboring a plasmid carrying the genes. Disruption of the genes in the chromosomal DNA of YM644 made the cells sensitive to the drugs.

Patupilone (epothilone B) inhibits growth and survival of multiple myeloma cells in vitro and in vivo

Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 350-357 ◽  
Author(s):  
Boris Lin ◽  
Laurence Catley ◽  
Richard LeBlanc ◽  
Constantine Mitsiades ◽  
Renate Burger ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Growth Factor ◽  
Efflux Pump ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Growth And Survival ◽  
Epothilone B ◽  
Endothelial Growth Factor

Abstract In this study, we investigated the in vitro and in vivo efficacy of patupilone (epothilone B, EPO906), a novel nontaxane microtubule stabilizing agent, in treatment of multiple myeloma (MM). Patupilone directly inhibited growth and survival of MM cells, including those resistant to conventional chemotherapies, such as the taxane paclitaxel. Patupilone induced G2M arrest of MM cells, with subsequent apoptosis. Interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1), 2 known growth and survival factors for MM, did not protect MM.1S cells against patupilone-induced cell death. Proliferation of MM cells induced by adherence to bone marrow stromal cells (BMSCs) was also inhibited by patupilone and was paralleled by down-regulation of vascular endothelial growth factor (VEGF) secretion. Importantly, stimulation of cells from patients with MM, either with IL-6 or by adherence to BMSCs, enhanced the anti-proliferative and proapoptotic effects of patupilone. Moreover, patupilone was effective against MM cell lines that overexpress the MDR1/P-glycoprotein multidrug efflux pump. In addition, patupilone was effective in slowing tumor growth and prolonging median survival of mice that received orthotopical transplants with MM tumor cells. Taken together, these preclinical findings suggest that patupilone may be a safe and effective drug in the treatment of MM, providing the framework for clinical studies to improve patient outcome in MM. (Blood. 2005;105:350-357)

scholarly journals Activities of Newer Fluoroquinolones against Ciprofloxacin-Resistant Streptococcus pneumoniae

2001 ◽  
Vol 45 (6) ◽  
pp. 1654-1659 ◽  
Author(s):  
Elizabeth A. Coyle ◽  
Glenn W. Kaatz ◽  
Michael J. Rybak
Keyword(s):  
Streptococcus Pneumoniae ◽  
Efflux Pump ◽  
Specific Area ◽  
Cross Resistance ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Time Curve ◽  
Ciprofloxacin Resistance ◽  
Derivatives Of

ABSTRACT The incidence of ciprofloxacin resistance in Streptococcus pneumoniae is low but steadily increasing, which raises concerns regarding the clinical impact of potential cross-resistance with newer fluoroquinolones. To investigate this problem, we utilized an in vitro pharmacodynamic model and compared the activities of gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin to that of ciprofloxacin against two laboratory-derived, ciprofloxacin-resistant derivatives of S. pneumoniae (strains R919 and R921). Ciprofloxacin resistance in these strains involved the activity of a multidrug efflux pump and possibly, for R919, a mutation resulting in an amino acid substitution in GyrA. Gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin achieved 99.9% killing of both R919 and R921 in ≤28 h. With respect to levofloxacin, significant regrowth of both mutants was observed at 48 h (P < 0.05). For gatifloxacin, grepafloxacin, moxifloxacin, and trovafloxacin, regrowth was minimal at 48 h, with each maintaining 99.9% killing against both mutants. No killing of either R919 or R921 was observed with exposure to ciprofloxacin. During model experiments, resistance to gatifloxacin, grepafloxacin, moxifloxacin, and trovafloxacin did not develop but the MICs of ciprofloxacin and levofloxacin increased 1 to 2 dilutions for both R919 and R921. Although specific area under the concentration-time curve from 0 to 24 h (AUC0–24)/MIC and maximum concentration of drug in serum (C max)/MIC ratios have not been defined for the fluoroquinolones with respect to gram-positive organisms, our study revealed that significant regrowth and/or resistance was associated with AUC0–24/MIC ratios of ≤31.7 and C max/MIC ratios of ≤3.1. It is evident that the newer fluoroquinolones tested possess improved activity against S. pneumoniae, including strains for which ciprofloxacin MICs were elevated.

scholarly journals Molecular Mechanism of MBX2319 Inhibition of Escherichia coli AcrB Multidrug Efflux Pump and Comparison with Other Inhibitors

2014 ◽  
Vol 58 (10) ◽  
pp. 6224-6234 ◽  
Author(s):  
Attilio V. Vargiu ◽  
Paolo Ruggerone ◽  
Timothy J. Opperman ◽  
Son T. Nguyen ◽  
Hiroshi Nikaido
Keyword(s):  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Efflux Pump Inhibitor ◽  
Content Type ◽  
X Ray Crystallography ◽  
Resistance Nodulation Division ◽  
Hydrophobic Portion ◽  
Dynamics Simulations

ABSTRACTEfflux pumps of the resistance nodulation division (RND) superfamily, such as AcrB, make a major contribution to multidrug resistance in Gram-negative bacteria. The development of inhibitors of the RND pumps would improve the efficacy of current and next-generation antibiotics. To date, however, only one inhibitor has been cocrystallized with AcrB. Thus,in silicostructure-based analysis is essential for elucidating the interaction between other inhibitors and the efflux pumps. In this work, we used computer docking and molecular dynamics simulations to study the interaction between AcrB and the compound MBX2319, a novel pyranopyridine efflux pump inhibitor with potent activity against RND efflux pumps ofEnterobacteriaceaespecies, as well as other known inhibitors (D13-9001, 1-[1-naphthylmethyl]-piperazine, and phenylalanylarginine-β-naphthylamide) and the binding of doxorubicin to the efflux-defective F610A variant of AcrB. We also analyzed the binding of a substrate, minocycline, for comparison. Our results show that MBX2319 binds very tightly to the lower part of the distal pocket in the B protomer of AcrB, strongly interacting with the phenylalanines lining the hydrophobic trap, where the hydrophobic portion of D13-9001 was found to bind by X-ray crystallography. Additionally, MBX2319 binds to AcrB in a manner that is similar to the way in which doxorubicin binds to the F610A variant of AcrB. In contrast, 1-(1-naphthylmethyl)-piperazine and phenylalanylarginine-β-naphthylamide appear to bind to somewhat different areas of the distal pocket in the B protomer of AcrB than does MBX2319. However, all inhibitors (except D13-9001) appear to distort the structure of the distal pocket, impairing the proper binding of substrates.

scholarly journals Toxic Electrophiles Induce Expression of the Multidrug Efflux Pump MexEF-OprN in Pseudomonas aeruginosa through a Novel Transcriptional Regulator, CmrA

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Paulo Juarez ◽  
Katy Jeannot ◽  
Patrick Plésiat ◽  
Catherine Llanes
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Redox Homeostasis ◽  
Transcriptional Regulator ◽  
Significant Loss ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Content Type ◽  
Constitutive Overexpression

ABSTRACT The multidrug efflux system MexEF-OprN is produced at low levels in wild-type strains of Pseudomonas aeruginosa. However, in so-called nfxC mutants, mutational alteration of the gene mexS results in constitutive overexpression of the pump, along with increased resistance of the bacterium to chloramphenicol, fluoroquinolones, and trimethoprim. In this study, analysis of in vitro-selected chloramphenicol-resistant clones of strain PA14 led to the identification of a new class of MexEF-OprN-overproducing mutants (called nfxC2) exhibiting alterations in an as-yet-uncharacterized gene, PA14_38040 (homolog of PA2047 in strain PAO1). This gene is predicted to encode an AraC-like transcriptional regulator and was called cmrA (for chloramphenicol resistance activator). In nfxC2 mutants, the mutated CmrA increases its proper gene expression and upregulates the operon mexEF-oprN through MexS and MexT, resulting in a multidrug resistance phenotype without significant loss in bacterial virulence. Transcriptomic experiments demonstrated that CmrA positively regulates a small set of 11 genes, including PA14_38020 (homolog of PA2048), which is required for the MexS/T-dependent activation of mexEF-oprN. PA2048 codes for a protein sharing conserved domains with the quinol monooxygenase YgiN from Escherichia coli. Interestingly, exposure of strain PA14 to toxic electrophilic molecules (glyoxal, methylglyoxal, and cinnamaldehyde) strongly activates the CmrA pathway and upregulates MexEF-OprN and, thus, increases the resistance of P. aeruginosa to the pump substrates. A picture emerges in which MexEF-OprN is central in the response of the pathogen to stresses affecting intracellular redox homeostasis.

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