scholarly journals Overexpression of the MexXY Multidrug Efflux System Correlates with Deficient Pyoverdine Production in Pseudomonas aeruginosa

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 658
Author(s):  
Kei Ikarashi ◽  
Ryo Kutsuna ◽  
Junko Tomida ◽  
Yoshiaki Kawamura ◽  
Yuji Morita
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Resistance Mechanism ◽  
Multidrug Resistant ◽  
Multidrug Efflux ◽  
Aminoglycoside Resistance ◽  
Active Efflux ◽  
Multidrug Efflux Pumps ◽  
Primary Determinant ◽  
Healthcare Associated

Multidrug-resistant Pseudomonas aeruginosa poses a serious problem due to hospital- and healthcare-associated infections. A major drug resistance mechanism of P. aeruginosa involves active efflux via resistance nodulation cell division (RND)-type multidrug efflux pumps of which MexXY is increasingly recognized as a primary determinant of aminoglycoside resistance in P. aeruginosa. MexXY overexpression is often observed in drug-resistant P. aeruginosa clinical isolates. MexXY deficiency increased pyoverdine production in all four P. aeruginosa strains we tested. MexXY-overproducing multidrug-resistant P. aeruginosa PA7 exhibited the greatest effect among the strains. Complementation with a MexXY-expressing plasmid restored low-level pyoverdine production in a MexXY-deficient P. aeruginosa mutant from PA7, indicating that MexXY expression decreases pyoverdine production. Because P. aeruginosa produces pyoverdine to acquire iron, MexXY-deficient mutants might be more susceptible to iron deficiency than MexXY-producing strains or might require extra iron. High-risk clones of multidrug-resistant P. aeruginosa reportedly tend to be MexXY overproducers but defective pyoverdine producers. This study suggests that P. aeruginosa reduces production of a virulence factor after acquiring a drug resistance factor.

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

2017 ◽  
Vol 63 (12) ◽  
pp. 929-938 ◽  
Author(s):  
Manu Singh ◽  
Yvonne C.W. Yau ◽  
Shirley Wang ◽  
Valerie Waters ◽  
Ayush Kumar
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Multidrug Resistant ◽  
Regulatory Genes ◽  
Multidrug Efflux ◽  
Chronic Infections ◽  
Aminoglycoside Resistance ◽  
Resistance Nodulation Division ◽  
Lung Infections

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.

scholarly journals Aminoglycoside Efflux in Pseudomonas aeruginosa: Involvement of Novel Outer Membrane Proteins

2003 ◽  
Vol 47 (3) ◽  
pp. 1101-1111 ◽  
Author(s):  
James T. H. Jo ◽  
Fiona S. L. Brinkman ◽  
Robert E. W. Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Aminoglycoside Resistance ◽  
Multidrug Efflux Pumps ◽  
Knockout Mutants ◽  
Insertional Inactivation ◽  
Outer Membrane Channel

ABSTRACT The expression of tripartite multidrug efflux pumps such as MexA-MexB-OprM in Pseudomonas aeruginosa contributes to intrinsic resistance to a wide variety of antimicrobials, including β-lactams, chloramphenicol, macrolides, quinolones, and tetracycline. The MexX-MexY linker-pump combination has been shown to be involved in intrinsic resistance to aminoglycosides, but the identity of the cognate outer membrane channel component remains under debate. Fourteen uncharacterized OprM homologs identified in the genome of P. aeruginosa were examined as candidates for this role by assessing the minimum inhibitory concentrations (MICs) of aminoglycosides in P. aeruginosa strain PAK knockout mutants lacking the corresponding genes. Insertional inactivation of OpmG, OpmI, and OpmH resulted in decreases of various degrees in the MICs of streptomycin, kanamycin, and gentamicin. When reintroduced into P. aeruginosa on multicopy plasmids, OpmG was able to complement the susceptibility of an opmG::miniTn5 mutant; however, cloned opmH, the proposed ortholog of Escherichia coli tolC according to our phylogenetic analysis, was able to only partially complement the opmH::miniTn5 mutant. Mini-microarray hybridization analysis demonstrated that opmG disruption does not affect expression of OpmI or OpmH (ruling out such indirect effects on aminoglycoside resistance); however, opmH disruption did have possible effects on expression of OpmG and OpmI. Based on the data, we propose that OpmG is a major outer membrane efflux channel involved in aminoglycoside efflux in P. aeruginosa PAK and that OpmI, its most related paralog, may share an overlapping function.

scholarly journals Expression of Pseudomonas aeruginosa Multidrug Efflux Pumps MexA-MexB-OprM and MexC-MexD-OprJ in a Multidrug-Sensitive Escherichia coli Strain

1998 ◽  
Vol 42 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Ramakrishnan Srikumar ◽  
Tatiana Kon ◽  
Naomasa Gotoh ◽  
Keith Poole
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Crystal Violet ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Efflux ◽  
Efflux System ◽  
E Coli ◽  
Multidrug Efflux Pumps

ABSTRACT The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps inPseudomonas aeruginosa. To assess the contribution of individual components to antibiotic resistance and substrate specificity, these operons and their component genes were cloned and expressed in Escherichia coli. Western immunoblotting confirmed expression of the P. aeruginosa efflux pump components in E. coli strains expressing and deficient in the endogenous multidrug efflux system (AcrAB), although only the ΔacrAB strain, KZM120, demonstrated increased resistance to antibiotics in the presence of the P. aeruginosa efflux genes. E. coli KZM120 expressing MexAB-OprM showed increased resistance to quinolones, chloramphenicol, erythromycin, azithromycin, sodium dodecyl sulfate (SDS), crystal violet, novobiocin, and, significantly, several β-lactams, which is reminiscent of the operation of this pump in P. aeruginosa. This confirmed previous suggestions that MexAB-OprM provides a direct contribution to β-lactam resistance via the efflux of this group of antibiotics. An increase in antibiotic resistance, however, was not observed when MexAB or OprM alone was expressed in KZM120. Thus, despite the fact that β-lactams act within the periplasm, OprM alone is insufficient to provide resistance to these agents. E. coli KZM120 expressing MexCD-OprJ also showed increased resistance to quinolones, chloramphenicol, macrolides, SDS, and crystal violet, though not to most β-lactams or novobiocin, again somewhat reminiscent of the antibiotic resistance profile of MexCD-OprJ-expressing strains ofP. aeruginosa. Surprisingly, E. coli KZM120 expressing MexCD alone also showed an increase in resistance to these agents, while an OprJ-expressing KZM120 failed to demonstrate any increase in antibiotic resistance. MexCD-mediated resistance, however, was absent in a tolC mutant of KZM120, indicating that MexCD functions in KZM120 in conjunction with TolC, the previously identified outer membrane component of the AcrAB-TolC efflux system. These data confirm that a tripartite efflux pump is necessary for the efflux of all substrate antibiotics and that the P. aeruginosa multidrug efflux pumps are functional and retain their substrate specificity in E. coli.

scholarly journals Dehydrozingerone Exhibits Synergistic Antifungal Activities in Combination with Dodecanol against Budding Yeast via the Restriction of Multidrug Resistance

2018 ◽  
Vol 5 (02) ◽  
pp. e61-e67
Author(s):  
Chika Yamawaki ◽  
Yoshihiro Yamaguchi ◽  
Akira Ogita ◽  
Toshio Tanaka ◽  
Ken-ichi Fujita
Keyword(s):  
Drug Resistance ◽  
Antifungal Activity ◽  
Efflux Pump ◽  
Fungal Infections ◽  
Zingiber Officinale ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Yeast Saccharomyces Cerevisiae ◽  
Multidrug Transporters ◽  
Multidrug Efflux Pumps

AbstractDrug resistance in fungal infections has been a more frequent occurrence with the increasing number of immunocompromised patients. In efforts to overcome the problem of fungal drug resistance, we focused on the phenolic compound dehydrozingerone, which is isolated from Zingiber officinale. The effectiveness of this compound on the model yeast Saccharomyces cerevisiae has not been reported. In our study, dehydrozingerone showed a weak antifungal activity against the yeast, but demonstrated a synergistic effect in combination with dodecanol, which typically only restricts cell growth transiently. Efflux of rhodamine 6G through the multidrug efflux pumps was significantly restricted by dehydrozingerone. The transcription level of PDR5, encoding a primary multidrug efflux pump in S. cerevisiae, was enhanced with dodecanol treatment, whereas the level was reduced by dehydrozingerone. These results suggest that dehydrozingerone may be effective for potentiating antifungal activity of other drugs that are expelled from fungi by multidrug transporters like Pdr5p.

scholarly journals Functional and Structural Roles of the Major Facilitator Superfamily Bacterial Multidrug Efflux Pumps

2020 ◽  
Vol 8 (2) ◽  
pp. 266 ◽  
Author(s):  
Sanath Kumar ◽  
Manjusha Lekshmi ◽  
Ammini Parvathi ◽  
Manisha Ojha ◽  
Nicholas Wenzel ◽  
...  
Keyword(s):  
Amino Acid ◽  
Antimicrobial Agents ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Amino Acid Sequences ◽  
Major Facilitator Superfamily ◽  
Multidrug Efflux ◽  
Ion Translocation ◽  
Multidrug Efflux Pumps ◽  
Major Facilitator

Pathogenic microorganisms that are multidrug-resistant can pose severe clinical and public health concerns. In particular, bacterial multidrug efflux transporters of the major facilitator superfamily constitute a notable group of drug resistance mechanisms primarily because multidrug-resistant pathogens can become refractory to antimicrobial agents, thus resulting in potentially untreatable bacterial infections. The major facilitator superfamily is composed of thousands of solute transporters that are related in terms of their phylogenetic relationships, primary amino acid sequences, two- and three-dimensional structures, modes of energization (passive and secondary active), and in their mechanisms of solute and ion translocation across the membrane. The major facilitator superfamily is also composed of numerous families and sub-families of homologous transporters that are conserved across all living taxa, from bacteria to humans. Members of this superfamily share several classes of highly conserved amino acid sequence motifs that play essential mechanistic roles during transport. The structural and functional importance of multidrug efflux pumps that belong to the major facilitator family and that are harbored by Gram-negative and -positive bacterial pathogens are considered here.

scholarly journals Drug Resistance and Biofilm Production among Pseudomonas aeruginosa Clinical Isolates in a Tertiary Care Hospital of Nepal

2019 ◽  
Vol 21 (2) ◽  
pp. 110-116
Author(s):  
Rajani Shrestha ◽  
N. Nayak ◽  
D.R. Bhatta ◽  
D. Hamal ◽  
S.H. Subramanya ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Biofilm Formation ◽  
Tertiary Care ◽  
Clinical Problem ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Care Hospital ◽  
Microbiological Methods

Clinical isolates of Pseudomonas aeruginosa often exhibit multidrug resistance due to their inherent ability to form biofilms. Drug resistance in Ps. aeruginosa is a major clinical problem, especially in the management of patients with nosocomial infections and those admitted to ICUs with indwelling medical devices. To evaluate the biofilm forming abilities of the clinical isolates of Ps. aeruginosa and to correlate biofilm formation with antibiotic resistance. A total of 90 consecutive isolates of Ps. aeruginosa obtained from various specimens collected from patients visiting the Manipal Teaching Hospital, Pokhara, Nepal between January 2018 - October 2018 were studied. Isolates were identified by standard microbiological methods. Antibiotic susceptibility testing was performed by Kirby-Bauer disc diffusion method. All the isolates were tested for their biofilm forming abilities by employing the tissue culture plate assay. Of the 90 Ps. aeruginosa isolates, maximum i.e 42 (46.6%) were from patients in the age group of > 50 years. Majority (30; 33.3%) of the isolates were obtained from sputum samples. However, percentage isolation from other specimens like urine, endotracheal tube (ETT), pus, eye specimens and blood were 18.9%, 16.7%, 16.7%, 7.8% and 6.7% respectively. All the isolates were sensitive to polymixin B and colistin, 91.1% of the organisms were sensitive to imipenem, and more than 80% to aminoglycosides (80% to gentamicin, 83.3% to amikacin). A total of 29 (32.2%) organisms were biofilm producers. Maximum numbers of biofilm producing strains were obtained from ETT (8 of 15; 53.3%), pus (8 of 15; 53.3%) and blood (2 of 6; 33.3%) i.e from all invasive sites. None of the isolates from noninvasive specimens such as conjunctival swabs were biofilm positive. Significantly higher numbers of biofilm producers (23 of 29; 79.3%) were found to be multidrug resistant as compared to non-biofilm (6 of 61; 9.8%) producers (p=0.000). Ps. aeruginosa colonization leading to biofilm formation in deep seated tissues and on indwelling devices is a therapeutic challenge as majority of the isolates would be recalcitrant to commonly used antipseudomonal drugs. Effective monitoring of drug resistance patterns in all Pseudomonas clinical isolates should be a prerequisite for successful patient management.

scholarly journals Problematic clinical isolates of Pseudomonas aeruginosa from the university hospitals in Sofia, Bulgaria: current status of antimicrobial resistance and prevailing resistance mechanisms

2007 ◽  
Vol 56 (7) ◽  
pp. 956-963 ◽  
Author(s):  
Tanya Strateva ◽  
Vessela Ouzounova-Raykova ◽  
Boyka Markova ◽  
Albena Todorova ◽  
Yulia Marteva-Proevska ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Current Status ◽  
University Hospitals ◽  
Active Efflux ◽  
Genes Encoding

A total of 203 clinical isolates of Pseudomonas aeruginosa was collected during 2001–2006 from five university hospitals in Sofia, Bulgaria, to assess the current levels of antimicrobial susceptibility and to evaluate resistance mechanisms to antipseudomonal antimicrobial agents. The antibiotic resistance rates against the following antimicrobials were: carbenicillin 93.1 %, azlocillin 91.6 %, piperacillin 86.2 %, piperacillin/tazobactam 56.8 %, ceftazidime 45.8 %, cefepime 48.9 %, cefpirome 58.2 %, aztreonam 49.8 %, imipenem 42.3 %, meropenem 45.5 %, amikacin 59.1 %, gentamicin 79.7 %, tobramycin 89.6 %, netilmicin 69.6 % and ciprofloxacin 80.3 %. A total of 101 of the studied P. aeruginosa isolates (49.8 %) were multidrug resistant. Structural genes encoding class A and class D β-lactamases showed the following frequencies: bla VEB-1 33.1 %, bla PSE-1 22.5 %, bla PER-1 0 %, bla OXA-groupI 41.3 % and bla OXA-groupII 8.8 %. IMP- and VIM-type carbapenemases were not detected. In conclusion, the studied clinical strains of P. aeruginosa were problematic nosocomial pathogens. VEB-1 extended-spectrum β-lactamases appear to have a significant presence among clinical P. aeruginosa isolates from Sofia. Carbapenem resistance was related to non-enzymic mechanisms such as a deficiency of OprD proteins and active efflux.

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.

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