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https://www.readbyqxmd.com/read/28922614/mexxy-efflux-pump-overexpression-and-aminoglycoside-resistance-in-cystic-fibrosis-isolates-of-i-pseudomonas-aeruginosa-i-from-chronic-infections
#1
Manu Singh, Yvonne Yau, Shirley Wang, Valerie Waters, Ayush Kumar
In this study, we analyzed 15 multidrug resistant cystic fibrosis isolates of Pseudomonas aeruginosa from chronic lung infections for expression of four 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 four 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...
September 18, 2017: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28916560/cmeabc-multidrug-efflux-pump-contributes-to-antibiotic-resistance-and-promotes-campylobacter-jejuni-survival-and-multiplication-in-acanthamoeba-polyphaga
#2
Ana Vieira, Amritha Ramesh, Alan M Seddon, Andrey V Karlyshev
Campylobacter jejuni is a foodborne pathogen recognized as the leading cause of human bacterial gastroenteritis. The wide use of antibiotics in medicine and in animal husbandry has led to an increased incidence of antibiotic resistance in Campylobacter In addition to a role in multidrug resistance, the Campylobacter CmeABC RND-type efflux pump, which is associated with multidrug resistance (MDR), may also be involved in virulence. As a vehicle of pathogenic microorganisms, the protozoan Acanthamoeba is a good model for the investigation of bacterial survival in the environment and molecular mechanisms of pathogenicity...
September 15, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28900249/effect-of-efflux-pump-inhibition-on-pseudomonas-aeruginosa-transcriptome-and-virulence
#3
Giordano Rampioni, Cejoice Ramachandran Pillai, Francesca Longo, Roslen Bondì, Valerio Baldelli, Marco Messina, Francesco Imperi, Paolo Visca, Livia Leoni
Efflux pumps of the resistance-nodulation-cell-division (RND) family increase antibiotic resistance in many bacterial pathogens, representing candidate targets for the development of antibiotic adjuvants. RND pumps have also been proposed to contribute to bacterial infection, implying that efflux pump inhibitors (EPIs) could also act as anti-virulence drugs. Nevertheless, EPIs are usually investigated only for their properties as antibiotic adjuvants, while their potential anti-virulence activity is seldom taken into account...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28900020/petrobactin-is-exported-from-bacillus-anthracis-by-the-rnd-type-exporter-apex
#4
A K Hagan, A Tripathi, D Berger, D H Sherman, P C Hanna
Bacillus anthracis-a Gram-positive, spore-forming bacterium-causes anthrax, a highly lethal disease with high bacteremia titers. Such rapid growth requires ample access to nutrients, including iron. However, access to this critical metal is heavily restricted in mammals, which requires B. anthracis to employ petrobactin, an iron-scavenging small molecule known as a siderophore. Petrobactin biosynthesis is mediated by asb gene products, and import of the iron-bound (holo)-siderophore into the bacterium has been well studied...
September 12, 2017: MBio
https://www.readbyqxmd.com/read/28890187/kinetic-analysis-of-the-inhibition-of-the-drug-efflux-protein-acrb-using-surface-plasmon-resonance
#5
Rumana Mowla, Yinhu Wang, Shutao Ma, Henrietta Venter
Multidrug efflux protein complexes such as AcrAB-TolC from Escherichia coli are paramount in multidrug resistance in Gram-negative bacteria and are also implicated in other processes such as virulence and biofilm formation. Hence efflux pump inhibition, as a means to reverse antimicrobial resistance in clinically relevant pathogens, has gained increased momentum over the past two decades. Significant advances in the structural and functional analysis of AcrB have informed the selection of efflux pump inhibitors (EPIs)...
September 7, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28867620/complete-genome-sequence-analysis-of-the-fish-pathogen-flavobacterium-columnare-provides-insights-into-antibiotic-resistance-and-pathogenicity-related-genes
#6
Yulei Zhang, Lijuan Zhao, Wenjie Chen, Yunmao Huang, Ling Yang, V Sarathbabu, Zaohe Wu, Jun Li, Pin Nie, Li Lin
We analyzed here the complete genome sequences of a highly virulent Flavobacterium columnare Pf1 strain isolated in our laboratory. The complete genome consists of a 3,171,081 bp circular DNA with 2784 predicted protein-coding genes. Among these, 286 genes were predicted as antibiotic resistance genes, including 32 RND-type efflux pump related genes which were associated with the export of aminoglycosides, indicating inducible aminoglycosides resistances in F. columnare. On the other hand, 328 genes were predicted as pathogenicity related genes which could be classified as virulence factors, gliding motility proteins, adhesins, and many putative secreted proteases...
September 1, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28808284/molecular-rationale-behind-the-differential-substrate-specificity-of-bacterial-rnd-multi-drug-transporters
#7
Venkata Krishnan Ramaswamy, Attilio V Vargiu, Giuliano Malloci, Jürg Dreier, Paolo Ruggerone
Resistance-Nodulation-cell Division (RND) transporters AcrB and AcrD of Escherichia coli expel a wide range of substrates out of the cell in conjunction with AcrA and TolC, contributing to the onset of bacterial multidrug resistance. Despite sharing an overall sequence identity of ~66% (similarity ~80%), these RND transporters feature distinct substrate specificity patterns whose underlying basis remains elusive. We performed exhaustive comparative analyses of the putative substrate binding pockets considering crystal structures, homology models and conformations extracted from multi-copy μs-long molecular dynamics simulations of both AcrB and AcrD...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28806947/conessine-as-a-novel-inhibitor-of-multidrug-efflux-pump-systems-in-pseudomonas-aeruginosa
#8
Thanyaluck Siriyong, Potjanee Srimanote, Sasitorn Chusri, Boon-Ek Yingyongnarongkul, Channarong Suaisom, Varomyalin Tipmanee, Supayang Piyawan Voravuthikunchai
BACKGROUND: Holarrhena antidysenterica has been employed as an ethnobotanical plant for the treatment of dysentery, diarrhoea, fever, and bacterial infections. Biological activities of the principle compound, conessine including anti-diarrhoea and anti-plasmodial effects were documented. Our previous study reported potency of Holarrhena antidysenterica extract and conessine as resistance modifying agents against extensively drug-resistant Acinetobacter baumannii. This study aimed to investigate (i) whether conessine, a steroidal alkaloid compound, could act as a resistance modifying agent against multidrug-resistant Pseudomonas aeruginosa, and (ii) whether MexAB-OprM efflux pump involved in the mechanism...
August 14, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28764143/prevalence-of-flexible-flat-foot-in-adults-a-cross-sectional-study
#9
Ashok Aenumulapalli, Manoj Mohan Kulkarni, Achleshwar Ramnarain Gandotra
INTRODUCTION: Flat foot (pes planus) is a commonly observed disorder in clinical practice. The height of Medial Longitudinal Arch (MLA) determines the degree of pes planus. Majority of the previous studies on prevalence of flexible flat foot were done among children. AIM: The present study was undertaken to determine the prevalence of flexible flat foot among 18-21-year-old Indian adults using Navicular Drop Test (NDT) which is regarded as reliable and valid method to characterise MLA...
June 2017: Journal of Clinical and Diagnostic Research: JCDR
https://www.readbyqxmd.com/read/28760827/copper-homeostasis-networks-in-the-bacterium-pseudomonas-aeruginosa
#10
Julia Quintana, Lorena Novoa-Aponte, José M Argüello
Bacterial copper (Cu(+)) homeostasis enables both precise metallation of diverse cuproproteins and control of variable metal levels. To this end, protein networks mobilize Cu(+) to cellular targets with remarkable specificity. However, the understanding of these processes is rather fragmented. Here, we use genome-wide transcriptomic analysis by RNA-Seq to characterize the response of Pseudomonas aeruginosa to external 0.5 mM CuSO4, a condition that did not generate pleiotropic effects. Pre-steady (5 min) and steady state (2 h) Cu(+) fluxes, resulted in distinct transcriptome landscapes...
July 31, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28720734/lack-of-acrb-efflux-function-confers-loss-of-virulence-on-salmonella-enterica-serovar-typhimurium
#11
Xuan Wang-Kan, Jessica M A Blair, Barbara Chirullo, Jonathan Betts, Roberto M La Ragione, Alasdair Ivens, Vito Ricci, Timothy J Opperman, Laura J V Piddock
AcrAB-TolC is the paradigm resistance-nodulation-division (RND) multidrug resistance efflux system in Gram-negative bacteria, with AcrB being the pump protein in this complex. We constructed a nonfunctional AcrB mutant by replacing D408, a highly conserved residue essential for proton translocation. Western blotting confirmed that the AcrB D408A mutant had the same native level of expression of AcrB as the parental strain. The mutant had no growth deficiencies in rich or minimal medium. However, compared with wild-type SL1344, the mutant had increased accumulation of Hoechst 33342 dye and decreased efflux of ethidium bromide and was multidrug hypersusceptible...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28689875/contribution-of-acrab-tolc-to-multidrug-resistance-in-an-escherichia-coli-sequence-type-131-isolate
#12
Sabine Schuster, Martina Vavra, Tobias M Schweigger, John W A Rossen, Yasufumi Matsumura, Winfried V Kern
Drug efflux by resistance-nodulation-cell division (RND)-type transporters, such as AcrAB-TolC of Escherichia coli, is an important resistance mechanism in Gram-negative bacteria; however, its contribution to multidrug resistance (MDR) in clinical isolates is poorly defined. We inactivated acrB of a sequence type 131 E. coli human isolate that showed high-level MDR, but had no mutations within the known efflux-associated local or global regulators. The resistance profile of the acrB deletion mutant revealed significantly increased susceptibility to drugs from seven antibiotic classes, including agents usually inactive against Gram-negative bacteria, notably the new oxazolidinone, tedizolid (512-fold enhanced susceptibility)...
July 6, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28631419/the-cpxr-cpxa-system-contributes-to-salmonella-gold-resistance-by-controlling-the-gols-dependent-gesabc-transcription
#13
Sebastián Cerminati, Germán F Giri, Julián I Mendoza, Fernando C Soncini, Susana K Checa
Several regulatory systems contribute to bacterial resistance to heavy metals controlling the expression of factors required to eliminate the intoxicant and/or to repair the damage caused by it. In Salmonella, the response to Au ions is mediated by the specific metalloregulator GolS that, among other genes, controls the expression of the RND-efflux pump GesABC. In this work, we demonstrate that CpxR/CpxA, a main cell-envelope stress-responding system, promotes gesABC transcription in the presence of Au ions at neutral pH...
June 19, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28584156/role-of-axyz-transcriptional-regulator-in-overproduction-of-axyxy-oprz-multidrug-efflux-system-in-achromobacter-species-mutants-selected-by-tobramycin
#14
Julien Bador, Catherine Neuwirth, Nadège Grangier, Marie Muniz, Leslie Germé, Jérémy Bonnet, Vignesh-Guru Pillay, Catherine Llanes, Claire de Curraize, Lucie Amoureux
AxyXY-OprZ is an RND-type efflux system that confers innate aminoglycoside resistance to Achromobacter spp. We investigated here a putative TetR family transcriptional regulator encoded by the axyZ gene located upstream of axyXY-oprZ An in-frame axyZ gene deletion assay led to increased MICs of antibiotic substrates of the efflux system, including aminoglycosides, cefepime, fluoroquinolones, tetracyclines, and erythromycin, indicating that the product of axyZ negatively regulates expression of axyXY-oprZ Moreover, we identified an amino acid substitution at position 29 of AxyZ (V29G) in a clinical Achromobacter strain that occurred during the course of chronic respiratory tract colonization in a cystic fibrosis (CF) patient...
August 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28538019/if-background-lung-abnormalities-do-not-affect-the-presentation-of-spontaneous-pneumothorax-is-lung-resection-always-justified
#15
Rocco Bilancia, Annabel J Sharkey, Amit Paik, David A Waller
BACKGROUND: The suggestion that spontaneous pneumothorax (SP) may result from diffuse porosity rather than discrete anatomic abnormality challenges the practice of targeted bullectomy. We assessed whether underlying pulmonary abnormalities are correlated or could be predicted from the mode of presentation, with potential implications for treatment. METHODS: We analyzed 192 consecutive video-assisted thoracoscopic surgery resections for SP (139 primary, 53 secondary) in 171 patients (115 male, age 36, range, 16 to 81)...
July 2017: Journal of Bronchology & Interventional Pulmonology
https://www.readbyqxmd.com/read/28536672/response-to-bile-salts-in-clinical-strains-of-acinetobacter-baumannii-lacking-the-adeabc-efflux-pump-virulence-associated-with-quorum-sensing
#16
Maria López, Lucia Blasco, Eva Gato, Astrid Perez, Laura Fernández-Garcia, Luis Martínez-Martinez, Felipe Fernández-Cuenca, Jesús Rodríguez-Baño, Alvaro Pascual, German Bou, Maria Tomás
Introduction:Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28522287/patterns-of-regional-lymphadenectomy-for-clinically-node-negative-patients-with-penile-carcinoma-analysis-from-the-national-cancer-database-from-1998-to-2012
#17
Juan Chipollini, Dominic H Tang, Pranav Sharma, Adam S Baumgarten, Philippe E Spiess
PURPOSE: Evidence supports upfront regional lymphadenectomy (rND) when primary penile tumors exhibit high-risk features and negative inguinal adenopathy (cN0). We sought to analyze trends in the utilization of early rND as well as assess factors associated with its use and survival outcomes using a nationwide cancer registry database. PATIENT AND METHODS: The National Cancer Database was queried for patients with clinically nonmetastatic penile carcinoma and available nodal status who underwent rND from 1998 to 2012...
April 26, 2017: Clinical Genitourinary Cancer
https://www.readbyqxmd.com/read/28512090/the-vibrio-cholerae-vexgh-rnd-efflux-system-maintains-cellular-homeostasis-by-effluxing-vibriobactin
#18
Dillon E Kunkle, X Renee Bina, James E Bina
Resistance-nodulation-division (RND) superfamily efflux systems have been widely studied for their role in antibiotic resistance, but their native biological functions remain poorly understood. We previously showed that loss of RND-mediated efflux in Vibrio cholerae resulted in activation of the Cpx two-component regulatory system, which mediates adaptation to stress resulting from misfolded membrane proteins. Here, we investigated the mechanism linking RND-mediated efflux to the Cpx response. We performed transposon mutagenesis screening of RND-deficient V...
May 16, 2017: MBio
https://www.readbyqxmd.com/read/28462872/interaction-of-ethidium-and-tetraphenylphosphonium-cations-with-salmonella-enterica-cells
#19
Valeryia Mikalayeva, Sandra Sakalauskaitė, Rimantas Daugelavičius
BACKGROUND AND OBJECTIVE: One of the main causes of bacterial resistance to antimicrobials is multidrug resistance induced by the increased efficiency of the efflux pumps. In this study we analyzed how the conditions of assay affect the efflux of indicator substrates ethidium (Et(+)) and tetraphenylphosphonium (TPP(+)) in Salmonella enterica ser. Typhimurium cells. Impact of the outer membrane permeability barrier, composition and temperature of the medium on accumulation of the indicator compounds also was analyzed...
April 17, 2017: Medicina
https://www.readbyqxmd.com/read/28352264/indole-induced-activities-of-%C3%AE-lactamase-and-efflux-pump-confer-ampicillin-resistance-in-pseudomonas-putida-kt2440
#20
Jisun Kim, Bora Shin, Chulwoo Park, Woojun Park
Indole, which is widespread in microbial communities, has received attention because of its effects on bacterial physiology. Pseudomonas putida and Pseudomonas aeruginosa can acquire ampicillin (Amp) resistance during growth on indole-Amp agar. Transcriptome, mutant, and inhibitor studies have suggested that Amp resistance induced by indole can be attributed to increased gene expression of ttgAB encoding two genes of RND-type multidrug efflux operons and an ampC encoding β-lactamase. Expression, enzyme activities, and mutational analyses indicated that AmpC β-lactamase is important for acquiring Amp resistance of P...
2017: Frontiers in Microbiology
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