scholarly journals Antibiotic Susceptibility Profiles ofEscherichia coli Strains Lacking Multidrug Efflux Pump Genes

2001 ◽  
Vol 45 (4) ◽  
pp. 1126-1136 ◽  
Author(s):  
Mark C. Sulavik ◽  
Chad Houseweart ◽  
Christina Cramer ◽  
Nilofer Jiwani ◽  
Nicholas Murgolo ◽  
...  

ABSTRACT The contribution of seven known and nine predicted genes or operons associated with multidrug resistance to the susceptibility of Escherichia coli W3110 was assessed for 20 different classes of antimicrobial compounds that include antibiotics, antiseptics, detergents, and dyes. Strains were constructed with deletions for genes in the major facilitator superfamily, the resistance nodulation-cell division family, the small multidrug resistance family, the ATP-binding cassette family, and outer membrane factors. The agar dilution MICs of 35 compounds were determined for strains with deletions for multidrug resistance (MDR) pumps. Deletions in acrAB or tolC resulted in increased susceptibilities to the majority of compounds tested. The remaining MDR pump gene deletions resulted in increased susceptibilities to far fewer compounds. The results identify which MDR pumps contribute to intrinsic resistance under the conditions tested and supply practical information useful for designing sensitive assay strains for cell-based screening of antibacterial compounds.

2020 ◽  
Author(s):  
Yaojun Tong ◽  
Nuo Sun ◽  
Xiangming Wang ◽  
Qi Wei ◽  
Yu Zhang ◽  
...  

AbstractClinical use of antimicrobials faces great challenges from the emergence of multidrug resistant (MDR) pathogens. The overexpression of drug efflux pumps is one of the major contributors to MDR. It is considered as a promising approach to overcome MDR by reversing the function of drug efflux pumps. In the life-threatening fungal pathogen Candida albicans, the major facilitator superfamily (MFS) transporter Mdr1p can excrete many structurally unrelated antifungals, leading to multidrug resistance. Here we report a counterintuitive case of reversing multidrug resistance in C. albicans by using a natural product berberine to hijack the overexpressed Mdr1p for its own importation. Moreover, we illustrate that the imported berberine accumulates in mitochondria, and compromises the mitochondrial function by impairing mitochondrial membrane potential and mitochondrial Complex I. It results in the selective elimination of Mdr1p overexpressed C. albicans cells. Furthermore, we show that berberine treatment can prolong the mean survival time (MST) of mice with a blood-borne dissemination of Mdr1p overexpressed multidrug resistant candidiasis. This study provided a potential direction of novel anti-MDR drug discovery by screening for multidrug efflux pump converters.


2009 ◽  
Vol 53 (9) ◽  
pp. 4013-4014 ◽  
Author(s):  
I. Roca ◽  
S. Marti ◽  
P. Espinal ◽  
P. Martínez ◽  
I. Gibert ◽  
...  

ABSTRACT Acinetobacter baumannii has been increasingly associated with hospital-acquired infections, and the presence of multidrug resistance strains is of great concern to clinicians. A. baumannii is thought to possess a great deal of intrinsic resistance to several antimicrobial agents, including chloramphenicol, although the mechanisms involved in such resistance are not well understood. In this work, we have identified a major facilitator superfamily efflux pump present in most A. baumannii strains, displaying strong substrate specificity toward chloramphenicol.


2011 ◽  
Vol 77 (9) ◽  
pp. 2855-2862 ◽  
Author(s):  
Shima Eda ◽  
Hisayuki Mitsui ◽  
Kiwamu Minamisawa

ABSTRACTThe contributions of multicomponent-type multidrug efflux pumps to antimicrobial resistance and nodulation ability inSinorhizobium melilotiwere comprehensively analyzed. Computational searches identified genes in theS. melilotistrain 1021 genome encoding 1 pump from the ATP-binding cassette family, 3 pumps from the major facilitator superfamily, and 10 pumps from the resistance-nodulation-cell division family, and subsequently, these genes were deleted either individually or simultaneously. Antimicrobial susceptibility tests demonstrated that deletion of thesmeABpump genes resulted in increased susceptibility to a range of antibiotics, dyes, detergents, and plant-derived compounds and, further, that specific deletion of thesmeCDorsmeEFgenes in a ΔsmeABbackground caused a further increase in susceptibility to certain antibiotics. Competitive nodulation experiments revealed that thesmeABmutant was defective in competing with the wild-type strain for nodulation. The introduction of a plasmid carryingsmeABinto thesmeABmutant restored antimicrobial resistance and nodulation competitiveness. These findings suggest that the SmeAB pump, which is a major multidrug efflux system ofS. meliloti, plays an important role in nodulation competitiveness by mediating resistance toward antimicrobial compounds produced by the host plant.


2010 ◽  
Vol 54 (12) ◽  
pp. 5406-5412 ◽  
Author(s):  
Jody L. Floyd ◽  
Kenneth P. Smith ◽  
Sanath H. Kumar ◽  
Jared T. Floyd ◽  
Manuel F. Varela

ABSTRACT A multidrug efflux pump designated LmrS (lincomycin resistance protein of Staphylococcus aureus), belonging to the major facilitator superfamily (MFS) of transporters, was cloned, and the role of LmrS in antimicrobial efflux was evaluated. The highest relative increase in MIC, 16-fold, was observed for linezolid and tetraphenylphosphonium chloride (TPCL), followed by an 8-fold increase for sodium dodecyl sulfate (SDS), trimethoprim, and chloramphenicol. LmrS has 14 predicted membrane-spanning domains and is homologous to putative lincomycin resistance proteins of Bacillus spp., Lactobacillus spp., and Listeria spp.


FEBS Letters ◽  
2014 ◽  
Vol 588 (17) ◽  
pp. 3147-3153 ◽  
Author(s):  
Philip Hinchliffe ◽  
Nicholas P. Greene ◽  
Neil G. Paterson ◽  
Allister Crow ◽  
Colin Hughes ◽  
...  

2001 ◽  
Vol 45 (12) ◽  
pp. 3497-3503 ◽  
Author(s):  
Li Zhang ◽  
Xian-Zhi Li ◽  
Keith Poole

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.


2000 ◽  
Vol 182 (8) ◽  
pp. 2311-2313 ◽  
Author(s):  
Donald L. Jack ◽  
Michael L. Storms ◽  
Jason H. Tchieu ◽  
Ian T. Paulsen ◽  
Milton H. Saier

ABSTRACT The Bacillus subtilis genome encodes seven homologues of the small multidrug resistance (SMR) family of drug efflux pumps. Six of these homologues are paired in three distinct operons, and coexpression in Escherichia coli of one such operon,ykkCD, but not expression of either ykkC orykkD alone, gives rise to a broad specificity, multidrug-resistant phenotype including resistance to cationic, anionic, and neutral drugs.


Author(s):  
Zheng Fan ◽  
Xiaolei Pan ◽  
Dan Wang ◽  
Ronghao Chen ◽  
Tongtong Fu ◽  
...  

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.


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