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Tambat R, Mahey N, Chandal N, Verma DK, Jangra M, Thakur KG, Nandanwar H. A Microbe-Derived Efflux Pump Inhibitor of the Resistance-Nodulation-Cell Division Protein Restores Antibiotic Susceptibility in Escherichia coli and Pseudomonas aeruginosa. ACS Infect Dis 2022; 8:255-270. [PMID: 35045260 DOI: 10.1021/acsinfecdis.1c00281] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The use of efflux pump inhibitors (EPIs) as potentiators along with the traditional antibiotics assists in the warfare against antibiotic-resistant superbugs. Efflux pumps of the resistance-nodulation-cell division (RND) family play crucial roles in multidrug resistance in Escherichia coli and Pseudomonas aeruginosa. Despite several efforts, clinically useful inhibitors are not available at present. This study describes ethyl 4-bromopyrrole-2-carboxylate (RP1) isolation, an inhibitor of RND transporters from the library of 4000 microbial exudates. RP1 acts synergistically with antibiotics by reducing their minimum inhibitory concentration in strains overexpressing archetype RND transporters (AcrAB-TolC and MexAB-OprM). It also improves the accumulation of Hoechst 33342 and inhibits its efflux (a hallmark of EPI functionality). The antibiotic-RP1 combinations prolong the postantibiotic effects and reduce the mutation prevention concentration of antibiotics. Additionally, from Biolayer Interferometry spectra, it appears that RP1 is bound to AcrB. RP1 displays low mammalian cytotoxicity, no Ca2+ channel inhibitory effects, and reduces the intracellular invasion of E. coli and P. aeruginosa in macrophages. Furthermore, the RP1-levofloxacin combination is nontoxic, well-tolerated, and notably effective in a murine lung infection model. In sum, RP1 is a potent EPI and worthy of further consideration as a potentiator to improve the effectiveness of existing antibiotics.
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Affiliation(s)
- Rushikesh Tambat
- Clinical Microbiology & Antimicrobial Research Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
| | - Nisha Mahey
- Clinical Microbiology & Antimicrobial Research Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
- AcSIR−Academy of Scientific & Innovative Research, Ghaziabad, Uttar Pradesh 201002, India
| | - Nishtha Chandal
- Clinical Microbiology & Antimicrobial Research Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
- AcSIR−Academy of Scientific & Innovative Research, Ghaziabad, Uttar Pradesh 201002, India
| | - Dipesh Kumar Verma
- Structural Biology Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
| | - Manoj Jangra
- Clinical Microbiology & Antimicrobial Research Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
| | - Hemraj Nandanwar
- Clinical Microbiology & Antimicrobial Research Laboratory, CSIR−Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India
- AcSIR−Academy of Scientific & Innovative Research, Ghaziabad, Uttar Pradesh 201002, India
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Dawan J, Li Y, Lu F, He X, Ahn J. Role of Efflux Pump-Mediated Antibiotic Resistance in Quorum Sensing-Regulated Biofilm Formation by Salmonella Typhimurium. Pathogens 2022; 11:147. [PMID: 35215091 PMCID: PMC8877114 DOI: 10.3390/pathogens11020147] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
This study was designed to assess the influence of efflux pump activity on the biofilm formation in Salmonella Typhimurium. Salmonella enterica subsp. enterica serovar Typhimurium ATCC 19585 (STWT) and clinically isolated S. Typhimurium CCARM 8009 (STCI) were treated with ceftriaxone (CEF), chloramphenicol (CHL), ciprofloxacin (CIP), erythromycin (ERY), norfloxacin (NOR), and tetracycline (TET) in autoinducer-containing media in the absence and presence of phenylalanine-arginine β-naphthylamide (PAβN) to compare efflux pump activity with biofilm-forming ability. The susceptibilities of STWT and STCI were increased in the presence of PAβN. ERY+PAβN showed the highest decrease in the minimum inhibitory concentration (MIC) of ERY from 256 to 2 μg/mL against STWT and STCI. The antimicrobial activity of NOR against planktonic cells was significantly increased in the presence of PAβN, showing the lowest numbers of STWT (3.2 log CFU/cm2), and the TET+PAβN effectively inhibited the growth of STCI (5.2 log CFU/cm2). The lowest biofilm-forming abilities were observed at NOR+PAβN against STWT (biofilm-forming index, BFI < 0.41) and CEF+PAβN against STCI (BFI = 0.32). The bacteria swimming motility and relative fitness varied depending on the antibiotic and PAβN treatments. The motility diameters of STWT were significantly decreased by NOR+PAβN (6 mm) and TET+PAβN (15 mm), while the lowest motility of STCI was observed at CIP+PAβN (8 mm). The significant decrease in the relative fitness levels of STWT and STCI was observed at CIP+PAβN and NOR+PAβN. The PAβN as an efflux pump inhibitor (EPI) can improve the antimicrobial and anti-biofilm efficacy of antibiotics against S. Typhimurium. This study provides useful information for understanding the role of efflux pump activity in quorum sensing-regulated biofilm formation and also emphasizes the necessity of the discovery of novel EPIs for controlling biofilm formation by antibiotic-resistant pathogens.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
| | - Yinyue Li
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China; (Y.L.); (F.L.); (X.H.)
| | - Feng Lu
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China; (Y.L.); (F.L.); (X.H.)
| | - Xinlong He
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China; (Y.L.); (F.L.); (X.H.)
| | - Juhee Ahn
- Department of Biomedical Science, Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
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Urbaniec J, Xu Y, Hu Y, Hingley-Wilson S, McFadden J. Phenotypic heterogeneity in persisters: a novel 'hunker' theory of persistence. FEMS Microbiol Rev 2022; 46:fuab042. [PMID: 34355746 PMCID: PMC8767447 DOI: 10.1093/femsre/fuab042] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 08/04/2021] [Indexed: 12/11/2022] Open
Abstract
Persistence has been linked to treatment failure since its discovery over 70 years ago and understanding formation, nature and survival of this key antibiotic refractory subpopulation is crucial to enhancing treatment success and combatting the threat of antimicrobial resistance (AMR). The term 'persistence' is often used interchangeably with other terms such as tolerance or dormancy. In this review we focus on 'antibiotic persistence' which we broadly define as a feature of a subpopulation of bacterial cells that possesses the non-heritable character of surviving exposure to one or more antibiotics; and persisters as cells that possess this characteristic. We discuss novel molecular mechanisms involved in persister cell formation, as well as environmental factors which can contribute to increased antibiotic persistence in vivo, highlighting recent developments advanced by single-cell studies. We also aim to provide a comprehensive model of persistence, the 'hunker' theory which is grounded in intrinsic heterogeneity of bacterial populations and a myriad of 'hunkering down' mechanisms which can contribute to antibiotic survival of the persister subpopulation. Finally, we discuss antibiotic persistence as a 'stepping-stone' to AMR and stress the urgent need to develop effective anti-persister treatment regimes to treat this highly clinically relevant bacterial sub-population.
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Affiliation(s)
- J Urbaniec
- Department of Microbial Sciences and University of Surrey, Guildford, Surrey, GU27XH, UK
| | - Ye Xu
- Department of Microbial Sciences and University of Surrey, Guildford, Surrey, GU27XH, UK
| | - Y Hu
- Farnborough Sensonic limited, Farnborough road, GU14 7NA, UK
| | - S Hingley-Wilson
- Department of Microbial Sciences and University of Surrey, Guildford, Surrey, GU27XH, UK
| | - J McFadden
- Department of Microbial Sciences and University of Surrey, Guildford, Surrey, GU27XH, UK
- Quantum biology doctoral training centre, University of Surrey, Guildford, Surrey, GU27XH, UK
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OUP accepted manuscript. J Antimicrob Chemother 2022; 77:1272-1281. [DOI: 10.1093/jac/dkac044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/26/2022] [Indexed: 11/15/2022] Open
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Repurposing Approved Drugs as Fluoroquinolone Potentiators to Overcome Efflux Pump Resistance in Staphylococcus aureus. Microbiol Spectr 2021; 9:e0095121. [PMID: 34908453 PMCID: PMC8672906 DOI: 10.1128/spectrum.00951-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Staphylococcus aureus is a versatile human commensal bacteria and pathogen that causes various community and hospital-acquired infections. The S. aureus efflux pump NorA which belongs to the major facilitator superfamily, confers resistance to a range of substrates. Many efflux pump inhibitors (EPIs) have been discovered, but none is clinically approved due to their undesirable toxicities. In this study, we have screened clinically approved drugs for possible NorA EPI-like activity. We identified six drugs that showed the best efflux pump inhibition in vitro, with a fractional inhibitory concentration index of ≤0.5, indicating synergism with hydrophilic fluoroquinolones. The mechanistic validation of efflux inhibitory potential was demonstrated in ethidium bromide-based accumulation and efflux inhibition assays. We further confirmed the functionality of EPIs by norfloxacin accumulation assay depicting more realistic proof of the conjecture. None of the EPIs disturbed membrane function or depleted the ATP synthesis levels in bacteria. Both raloxifene and pyrvinium displayed an increase in bactericidal activity of ciprofloxacin in time-kill kinetics, prolonged its post-antibiotic effect, and reduced the frequency of spontaneous resistant mutant development. The combination of EPIs with ciprofloxacin caused significant eradication of preformed biofilms. Moreover, in the murine thigh infection model, a single dose of pyrvinium combined with ciprofloxacin reduced the bacterial burden significantly compared to untreated control and ciprofloxacin alone, indicating the efficacy of the combination. Conclusively, this study represents approved drugs that can be repurposed and combined with antibiotics as NorA EPIs, having anti-biofilm properties to treat severe S. aureus infections at clinically relevant concentrations. IMPORTANCEStaphylococcus aureus is a frequent pathogen bacterium and the predominant cause of worsened nosocomial infections. Efflux pumps contribute to drug efflux and are reportedly associated with biofilm formation, thereby promoting difficult-to-treat biofilm-associated S. aureus infections. One strategy to combat these bacteria is to reduce active efflux and increase pathogen sensitivity to existing antibiotics. Repurposing approved drugs may solve the classical toxicity issues with previous efflux pump inhibitors and help reach sufficient plasma concentrations. We describe the in silico-based screening of FDA-approved drugs that identified six different molecules able to inhibit NorA pump (Major Facilitator Superfamily). Our study highlights that these compounds bind to and block the activity of the NorA pump and increase the sensitivity of S. aureus and methicillin-resistant S. aureus to fluoroquinolones. These drugs combined with fluoroquinolones significantly reduced the preformed biofilms and displayed significant efficacy in the murine thigh infection model when compared to untreated control and ciprofloxacin alone.
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Cuesta Bernal J, El-Delik J, Göttig S, Pos KM. Characterization and Molecular Determinants for β-Lactam Specificity of the Multidrug Efflux Pump AcrD from Salmonella typhimurium. Antibiotics (Basel) 2021; 10:antibiotics10121494. [PMID: 34943706 PMCID: PMC8699017 DOI: 10.3390/antibiotics10121494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 11/24/2022] Open
Abstract
Gram-negative Tripartite Resistance Nodulation and cell Division (RND) superfamily efflux pumps confer various functions, including multidrug and bile salt resistance, quorum-sensing, virulence and can influence the rate of mutations on the chromosome. Multidrug RND efflux systems are often characterized by a wide substrate specificity. Similarly to many other RND efflux pump systems, AcrAD-TolC confers resistance toward SDS, novobiocin and deoxycholate. In contrast to the other pumps, however, it in addition confers resistance against aminoglycosides and dianionic β-lactams, such as sulbenicillin, aztreonam and carbenicillin. Here, we could show that AcrD from Salmonella typhimurium confers resistance toward several hitherto unreported AcrD substrates such as temocillin, dicloxacillin, cefazolin and fusidic acid. In order to address the molecular determinants of the S. typhimurium AcrD substrate specificity, we conducted substitution analyses in the putative access and deep binding pockets and in the TM1/TM2 groove region. The variants were tested in E. coli ΔacrBΔacrD against β-lactams oxacillin, carbenicillin, aztreonam and temocillin. Deep binding pocket variants N136A, D276A and Y327A; access pocket variant R625A; and variants with substitutions in the groove region between TM1 and TM2 conferred a sensitive phenotype and might, therefore, be involved in anionic β-lactam export. In contrast, lower susceptibilities were observed for E. coli cells harbouring deep binding pocket variants T139A, D176A, S180A, F609A, T611A and F627A and the TM1/TM2 groove variant I337A. This study provides the first insights of side chains involved in drug binding and transport for AcrD from S. typhimurium.
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Affiliation(s)
- Jenifer Cuesta Bernal
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany; (J.C.B.); (J.E.-D.)
| | - Jasmin El-Delik
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany; (J.C.B.); (J.E.-D.)
| | - Stephan Göttig
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Paul-Ehrlich-Straße 40, D-60596 Frankfurt am Main, Germany;
| | - Klaas M. Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany; (J.C.B.); (J.E.-D.)
- Correspondence:
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Microbial Efflux Pump Inhibitors: A Journey around Quinoline and Indole Derivatives. Molecules 2021; 26:molecules26226996. [PMID: 34834098 PMCID: PMC8618814 DOI: 10.3390/molecules26226996] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/12/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
Antimicrobial resistance (AMR) is a complex threat to human health and, to date, it represents a hot topic in drug discovery. The use of non-antibiotic molecules to block resistance mechanisms is a powerful alternative to the identification of new antibiotics. Bacterial efflux pumps exert the early step of AMR development, allowing the bacteria to grow in presence of sub-inhibitory drug concentration and develop more specific resistance mechanisms. Thus, efflux pump inhibitors (EPIs) offer a great opportunity to fight AMR, potentially restoring antibiotic activity. Based on our experience in designing and synthesizing novel EPIs, herein, we retrieved information around quinoline and indole derivatives reported in literature on this topic. Thus, our aim was to collect all data around these promising classes of EPIs in order to delineate a comprehensive structure–activity relationship (SAR) around each core for different microbes. With this review article, we aim to help future research in the field in the discovery of new microbial EPIs with improved activity and a better safety profile.
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Enantioselectivity of Chiral Derivatives of Xanthones in Virulence Effects of Resistant Bacteria. Pharmaceuticals (Basel) 2021; 14:ph14111141. [PMID: 34832923 PMCID: PMC8623869 DOI: 10.3390/ph14111141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 12/04/2022] Open
Abstract
Antimicrobial peptides are one of the lines of defense produced by several hosts in response to bacterial infections. Inspired by them and recent discoveries of xanthones as bacterial efflux pump inhibitors, chiral amides with a xanthone scaffold were planned to be potential antimicrobial adjuvants. The chiral derivatives of xanthones were obtained by peptide coupling reactions between suitable xanthones with enantiomerically pure building blocks, yielding derivatives with high enantiomeric purity. Among 18 compounds investigated for their antimicrobial activity against reference strains of bacteria and fungi, antibacterial activity for the tested strains was not found. Selected compounds were also evaluated for their potential to inhibit bacterial efflux pumps. Compound (R,R)-8 inhibited efflux pumps in the Gram-positive model tested and three compounds, (S,S)-8, (R)-17 and (R,S)-18, displayed the same activity in the Gram-negative strain used. Studies were performed on the inhibition of biofilm formation and quorum-sensing, to which the enantiomeric pair 8 displayed activity for the latter. To gain a better understanding of how the active compounds bind to the efflux pumps, docking studies were performed. Hit compounds were proposed for each activity, and it was shown that enantioselectivity was noticeable and must be considered, as enantiomers displayed differences in activity.
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Antibacterial, Antibiofilm, and Efflux Pump Inhibitory Properties of the Crude Extract and Fractions from Acacia macrostachya Stem Bark. ScientificWorldJournal 2021; 2021:5381993. [PMID: 34720766 PMCID: PMC8553507 DOI: 10.1155/2021/5381993] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/27/2021] [Accepted: 10/13/2021] [Indexed: 12/03/2022] Open
Abstract
Microbial infections remain a public health problem due to the upsurge of bacterial resistance. In this study, the antibacterial, antibiofilm, and efflux pump inhibitory activities of the stem bark of Acacia macrostachya, an indigenous African medicinal plant, were investigated. In traditional medicine, the plant is used in the treatment of microbial infections and inflammatory conditions. A crude methanol extract obtained by Soxhlet extraction was partitioned by column chromatography to obtain the petroleum ether, ethyl acetate, and methanol fractions. Antibacterial, efflux pump inhibition and antibiofilm formation activities were assessed by the high-throughput spot culture growth inhibition (HT-SPOTi), ethidium bromide accumulation, and the crystal violet retention assay, respectively. The minimum inhibitory concentrations (MICs) of the crude extract and major fractions ranged from 250 to ≥500 μg/mL. At a concentration of 3.9–250 μg/mL, all extracts demonstrated >80% inhibition of biofilm formation in S. aureus. In P. aeruginosa, the EtOAc fraction showed the highest antibiofilm activity (59–69%) while the pet-ether fraction was most active against E. coli biofilms (45–67%). Among the test samples, the crude extract, methanol, and ethyl acetate fractions showed remarkable efflux pump inhibition in S. aureus, E. coli, and P. aeruginosa. At ½ MIC, the methanol fraction demonstrated significant accumulation of EtBr in E. coli having superior efflux inhibition over the standard EPIs: chlorpromazine and verapamil. Tannins, flavonoids, triterpenoids, phytosterols, coumarins, and saponins were identified in preliminary phytochemical studies. Stigmasterol was identified in the EtOAc fraction. This study justifies the use of A. macrostachya in the treatment of infections in traditional medicine and highlights its potential as a source of bioactive compounds that could possibly interact with some resistance mechanisms in bacteria to combat antimicrobial resistance.
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Kaur B, Gupta J, Sharma S, Sharma D, Sharma S. Focused review on dual inhibition of quorum sensing and efflux pumps: A potential way to combat multi drug resistant Staphylococcus aureus infections. Int J Biol Macromol 2021; 190:33-43. [PMID: 34480904 DOI: 10.1016/j.ijbiomac.2021.08.199] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus is a common cause of skin infections, food poisoning and severe life-threatening infections. Methicillin-Resistant Staphylococcus aureus (MRSA) is known to cause chronic nosocomial infections by virtue of its multidrug resistance and biofilm formation mechanisms. The antimicrobial resistance owned by S. aureus is primarily due to efflux pumps and formation of microbial biofilms. These drug resistant, sessile and densely packed microbial communities possess various mechanisms including quorum sensing and drug efflux. Quorum sensing is a cooperative physiological process which is used by bacterial cells for social interaction and signal transduction in biofilm formation whereas efflux of drugs is derived by efflux pumps. Apart from their significant role in multidrug resistance, efflux pumps also contribute to transporting cell signalling molecules and due to their occurrence; we face the frightening possibility that we will enter the pre-antibiotic era soon. Compounds that modulate efflux pumps are also known as efflux pump inhibitors (EPI's) that act in a synergistic manner and potentiate the antibiotics efficacy which has been considered as a promising approach to encounter bacterial resistance. EPIs inhibit the mechanism of drug efflux s as well as transport of quorum sensing signalling molecules which are the supreme contributors of miscellaneous virulence factors. This review presents an accomplishments of the recent investigations allied to efflux pump inhibitors against S. aureus and also focus on related correspondence between quorum sensing system and efflux pump inhibitors in terms of S. aureus and MRSA biofilms that may open a new avenue for controlling MRSA infections.
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Affiliation(s)
- Bhawandeep Kaur
- Department of Medical Laboratory Sciences, Lovely Professional University, Phagwara, Punjab 144411, India
| | - Jeena Gupta
- Department of Biochemistry, Lovely Professional University, Phagwara, Punjab 144411, India
| | - Sarika Sharma
- Department of Life Sciences, Arni University, Indora, Kangra, H.P. 176402, India
| | - Divakar Sharma
- Department of Microbiology, Maulana Azad Medical College, New Delhi 110002, India.
| | - Sandeep Sharma
- Department of Medical Laboratory Sciences, Lovely Professional University, Phagwara, Punjab 144411, India.
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Cedraro N, Cannalire R, Astolfi A, Mangiaterra G, Felicetti T, Vaiasicca S, Cernicchi G, Massari S, Manfroni G, Tabarrini O, Cecchetti V, Barreca ML, Biavasco F, Sabatini S. From Quinoline to Quinazoline-Based S. aureus NorA Efflux Pump Inhibitors by Coupling a Focused Scaffold Hopping Approach and a Pharmacophore Search. ChemMedChem 2021; 16:3044-3059. [PMID: 34032014 PMCID: PMC8518402 DOI: 10.1002/cmdc.202100282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/23/2021] [Indexed: 11/29/2022]
Abstract
Antibiotic resistance breakers, such as efflux pump inhibitors (EPIs), represent a powerful alternative to the development of new antimicrobials. Recently, by using previously described EPIs, we developed pharmacophore models able to identify inhibitors of NorA, the most studied efflux pump of Staphylococcus aureus. Herein we report the pharmacophore-based virtual screening of a library of new potential NorA EPIs generated by an in-silico scaffold hopping approach of the quinoline core. After chemical synthesis and biological evaluation of the best virtual hits, we found the quinazoline core as the best performing scaffold. Accordingly, we designed and synthesized a series of functionalized 2-arylquinazolines, which were further evaluated as NorA EPIs. Four of them exhibited a strong synergism with ciprofloxacin and a good inhibition of ethidium bromide efflux on resistant S. aureus strains coupled with low cytotoxicity against human cell lines, thus highlighting a promising safety profile.
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Affiliation(s)
- Nicholas Cedraro
- Department of Life and Environmental SciencesUniversità Politecnica delle Marchevia Brecce Bianche60131AnconaItaly
| | - Rolando Cannalire
- Current address: Department of PharmacyUniversity of Napoli “Federico II”via D. Montesano 4980131NapoliItaly
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Andrea Astolfi
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Gianmarco Mangiaterra
- Department of Life and Environmental SciencesUniversità Politecnica delle Marchevia Brecce Bianche60131AnconaItaly
| | - Tommaso Felicetti
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Salvatore Vaiasicca
- Department of Life and Environmental SciencesUniversità Politecnica delle Marchevia Brecce Bianche60131AnconaItaly
| | - Giada Cernicchi
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Serena Massari
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Giuseppe Manfroni
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Oriana Tabarrini
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Violetta Cecchetti
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Maria Letizia Barreca
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
| | - Francesca Biavasco
- Department of Life and Environmental SciencesUniversità Politecnica delle Marchevia Brecce Bianche60131AnconaItaly
| | - Stefano Sabatini
- Department of Pharmaceutical SciencesUniversità degli Studi di Perugiavia del Liceo 106123PerugiaItaly
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Zhang W, Yuan Y, Li S, Deng B, Zhang J, Li Z. Comparative transcription analysis of resistant mutants against four different antibiotics in Pseudomonas aeruginosa. Microb Pathog 2021; 160:105166. [PMID: 34480983 DOI: 10.1016/j.micpath.2021.105166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/26/2021] [Accepted: 08/29/2021] [Indexed: 11/28/2022]
Abstract
The emergence of antibiotic resistance has severely impaired the treatment of infections caused by Pseudomonas aeruginosa. There are few studies related to comparing the antibiotics resistance mechanisms of P. aeruginosa against different antibiotics. In this study, RNA sequencing was used to investigate the differences of transcriptome between wild strain and four antibiotics resistant strains of P. aeruginosa PAO1 (polymyxin B, ciprofloxacin, doxycycline, and ceftriaxone). Compared to the wild strain, 1907, 495, 2402, and 116 differentially expressed genes (DEGs) were identified in polymyxin B, ciprofloxacin, doxycycline, and ceftriaxone resistant PAO1, respectively. After analysis of genes related to antimicrobial resistance, we found genes implicated in biofilm formation (pelB, pelC, pelD, pelE, pelF, pelG, algA, algF, and alg44) were significantly upregulated in polymyxin B-resistant PAO1, efflux pump genes (mexA, mexB, oprM) and biofilm formation genes (pslJ, pslK and pslN) were upregulated in ciprofloxacin-resistant PAO1; other efflux pump genes (mexC, mexD, oprJ) were upregulated in doxycycline-resistant PAO1; ampC were upregulated in ceftriaxone-resistant PAO1. As a consequence of antibiotic resistance, genes related to virulence factors such as type Ⅱ secretion system (lasA, lasB and piv) were significantly upregulated in polymyxin B-resistant PAO1, and type Ⅲ secretion system (exoS, exoT, exoY, exsA, exsB, exsC, exsD, pcrV, popB, popD, pscC, pscE, pscG, and pscJ) were upregulated in doxycycline-resistant PAO1. While, ampC were upregulated in ceftriaxone-resistant PAO1. In addition, variants were obtained in wild type and four antibiotics resistant PAO1. Our findings provide a comparative transcriptome analysis of antibiotic resistant mutants selected by different antibiotics, and might assist in identifying potential therapeutic strategies for P. aeruginosa infection.
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Affiliation(s)
- Wenlu Zhang
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, 471003, China
| | - Yaping Yuan
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, 471003, China
| | - Shasha Li
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, 471003, China
| | - Bo Deng
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, 471003, China
| | - Jiaming Zhang
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, 471003, China
| | - Zhongjie Li
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, 471003, China.
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Investigating Ghanaian Allium Species for Anti-Infective and Resistance-Reversal Natural Product Leads to Mitigate Multidrug-Resistance in Tuberculosis. Antibiotics (Basel) 2021; 10:antibiotics10080902. [PMID: 34438951 PMCID: PMC8388710 DOI: 10.3390/antibiotics10080902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 11/16/2022] Open
Abstract
The bulbs of Allium species are a known source of antibacterial phytochemicals. Anti-infective, efflux pump and biofilm inhibitory activities of bulb extracts of selected Ghanaian shallots Allium cepa var aggregatum were evaluated using the HT-SPOTi assay and other whole-cell phenotypic screening techniques to determine their possible mechanisms of action. Ethanol and aqueous extracts of white A. cepa inhibited the growth of Mycobacterium smegmatis mc2 155 and Escherichia coli, respectively. The majority of the Allium extracts significantly (p < 0.05) exhibited efflux pump inhibitory activity against all the acid-fast, Gram-positive and Gram-negative strains used. Hexane and chloroform extract of the pink A. cepa and the aqueous extract of the white A. cepa significantly inhibited M. smegmatis biofilm formation. For Pseudomonas aeruginosa, the inhibition was observed at 250 µg/mL for the aqueous extract (~77.34%) and 125 µg/mL for the hexane extract (~76.51%). The results suggest that Ghanaian shallots could potentially be useful when further developed to tackle antimicrobial resistance, particularly in tuberculosis (TB).
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Abstract
Rising antimicrobial resistance severely limits efforts to treat infections and is a cause for critical concern. Renewed interest in bacteriophage therapy has advanced understanding of the breadth of species capable of targeting bacterial antimicrobial resistance mechanisms, but many questions concerning ideal application remain unanswered. The following minireview examines bacterial resistance mechanisms, the current state of bacteriophage therapy, and how bacteriophage therapy can augment strategies to combat resistance with a focus on the clinically relevant bacterium Pseudomonas aeruginosa, as well as the role of efflux pumps in antimicrobial resistance. Methods to prevent antimicrobial efflux using efflux pump inhibitors and phage steering, a type of bacteriophage therapy, are also covered. The evolutionary context underlying antimicrobial resistance and the need to include theory in the ongoing development of bacteriophage therapy are also discussed.
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Antifungal Azoles as Tetracycline Resistance Modifiers in Staphylococcus aureus. Appl Environ Microbiol 2021; 87:e0015521. [PMID: 33990311 DOI: 10.1128/aem.00155-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus has developed resistance to antimicrobials since their first use. The S. aureus major facilitator superfamily (MFS) efflux pump Tet(K) contributes to resistance to tetracyclines. The efflux pump diminishes antibiotic accumulation, and biofilm hampers the diffusion of antibiotics. None of the currently known compounds have been approved as efflux pump inhibitors (EPIs) for clinical use. In the current study, we screened clinically approved drugs for possible Tet(K) efflux pump inhibition. By performing in silico docking followed by in vitro checkerboard assays, we identified five azoles (the fungal ergosterol synthesis inhibitors) showing putative EPI-like potential with a fractional inhibitory concentration index of ≤0.5, indicating synergism. The functionality of the azoles was confirmed using ethidium bromide (EtBr) accumulation and efflux inhibition assays. In time-kill kinetics, the combination treatment with butoconazole engendered a marked increase in the bactericidal capacity of tetracycline. When assessing the off-target effects of the azoles, we observed no disruption of bacterial membrane permeability and polarization. Finally, the combination of azoles with tetracycline led to a significant eradication of preformed mature biofilms. This study demonstrates that azoles can be repurposed as putative Tet(K) EPIs and to reduce biofilm formation at clinically relevant concentrations. IMPORTANCE Staphylococcus aureus uses efflux pumps to transport antibiotics out of the cell and thus increases the dosage at which it endures antibiotics. Also, efflux pumps play a role in biofilm formation by the excretion of extracellular matrix molecules. One way to combat these pathogens may be to reduce the activity of efflux pumps and thereby increase pathogen sensitivity to existing antibiotics. We describe the in silico-based screen of clinically approved drugs that identified antifungal azoles inhibiting Tet(K), a pump that belongs to the major facilitator superfamily, and showed that these compounds bind to and block the activity of the Tet(K) pump. Azoles enhanced the susceptibility of tetracycline against S. aureus and its methicillin-resistant strains. The combination of azoles with tetracycline led to a significant reduction in preformed biofilms. Repurposing approved drugs may help solve the classical toxicity issues related to efflux pump inhibitors.
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Mateus C, Nunes AR, Oleastro M, Domingues F, Ferreira S. RND Efflux Systems Contribute to Resistance and Virulence of Aliarcobacter butzleri. Antibiotics (Basel) 2021; 10:823. [PMID: 34356744 PMCID: PMC8300790 DOI: 10.3390/antibiotics10070823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/01/2021] [Accepted: 07/05/2021] [Indexed: 12/22/2022] Open
Abstract
Aliarcobacter butzleri is an emergent enteropathogen that can be found in a range of environments. This bacterium presents a vast repertoire of efflux pumps, such as the ones belonging to the resistance nodulation cell division family, which may be associated with bacterial resistance, as well as virulence. Thus, this work aimed to evaluate the contribution of three RND efflux systems, AreABC, AreDEF and AreGHI, in the resistance and virulence of A. butzleri. Mutant strains were constructed by inactivation of the gene that encodes the inner membrane protein of these systems. The bacterial resistance profile of parental and mutant strains to several antimicrobials was assessed, as was the intracellular accumulation of the ethidium bromide dye. Regarding bacterial virulence, the role of these three efflux pumps on growth, strain fitness, motility, biofilm formation ability, survival in adverse conditions (oxidative stress and bile salts) and human serum and in vitro adhesion and invasion to Caco-2 cells was evaluated. We observed that the mutants from the three efflux pumps were more susceptible to several classes of antimicrobials than the parental strain and presented an increase in the accumulation of ethidium bromide, indicating a potential role of the efflux pumps in the extrusion of antimicrobials. The mutant strains had no bacterial growth defects; nonetheless, they presented a reduction in relative fitness. For the three mutants, an increase in the susceptibility to oxidative stress was observed, while only the mutant for AreGHI efflux pump showed a relevant role in bile stress survival. All the mutant strains showed an impairment in biofilm formation ability, were more susceptible to human serum and were less adherent to intestinal epithelial cells. Overall, the results support the contribution of the efflux pumps AreABC, AreDEF and AreGHI of A. butzleri to antimicrobial resistance, as well as to bacterial virulence.
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Affiliation(s)
- Cristiana Mateus
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| | - Ana Rita Nunes
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| | - Mónica Oleastro
- National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal;
| | - Fernanda Domingues
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| | - Susana Ferreira
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
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ToxR Mediates the Antivirulence Activity of Phenyl-Arginine-β-Naphthylamide To Attenuate Vibrio cholerae Virulence. Infect Immun 2021; 89:e0014721. [PMID: 33941578 DOI: 10.1128/iai.00147-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidrug efflux systems belonging to the resistance-nodulation-cell division (RND) family are ubiquitous in Gram-negative bacteria and are critical for antimicrobial resistance. This realization has led to efforts to develop efflux pump inhibitors (EPI) for use as adjuvants for antibiotic treatment of resistant organisms. However, the functions of RND transporters extend beyond antimicrobial resistance to include physiological functions that are critical for pathogenesis, suggesting that EPIs could also be used as antivirulence therapeutics. This was documented in the enteric pathogen Vibrio cholerae, in which EPIs were shown to attenuate the production of the critical virulence factors cholera toxin (CT) and the toxin-coregulated pilus (TCP). In this study, we investigated the antivirulence mechanism of action of the EPI phenyl-arginine-β-naphthylamide (PAβN) on V. cholerae. Using bioassays, we documented that PAβN inhibited virulence factor production in three epidemic V. cholerae isolates. Transcriptional reporter studies and mutant analysis indicated that PAβN initiated a ToxR-dependent regulatory circuit to activate leuO expression and that LeuO repressed the expression of the critical virulence activator aphA to attenuate CT and TCP production. The antivirulence activity of PAβN was found to be dependent on the ToxR periplasmic sensing domain (PPD), suggesting that a feedback mechanism was involved in its activity. Collectively, the data indicated that PAβN inhibited V. cholerae virulence factor production by activating a ToxR-dependent metabolic feedback mechanism to repress the expression of the ToxR virulence regulon. This suggests that efflux pump inhibitors could be used as antivirulence therapeutics for the treatment of cholera and perhaps that of other Gram-negative pathogens.
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Ma F, Zhou H, Yang Z, Wang C, An Y, Ni L, Liu M, Wang Y, Yu L. Gene expression profile analysis and target gene discovery of Mycobacterium tuberculosis biofilm. Appl Microbiol Biotechnol 2021; 105:5123-5134. [PMID: 34125278 DOI: 10.1007/s00253-021-11361-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 04/27/2021] [Accepted: 05/20/2021] [Indexed: 10/21/2022]
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tuberculosis) is a fatal infectious disease to human health, and the drug tolerance and immune evasion of M. tuberculosis were reported to be related to its biofilm formation; however, the difficulty of M. tuberculosis biofilm culture and its unknown global mechanism impede its further research. Here, we developed a modified in vitro M. tuberculosis biofilm model with shorter culture time. Then we used Illumina RNA-seq technology to determine the global gene expression profile of M. tuberculosis H37Rv biofilms. Over 437 genes are expressed at significantly different levels in biofilm cells than in planktonic cells; among them, 153 were downregulated and 284 were upregulated. Go enrichment analysis and KEGG pathway analysis showed that genes involved in biosynthesis and metabolism of sulfur metabolism, steroid degradation, atrazine degradation, mammalian cell entry protein complex, etc. are involved in M. tuberculosis biofilm cells. Especially, ATP-binding cassette (ABC) transporters Rv1217c and Rv1218c were significantly upregulated in biofilm, whereas efflux pump inhibitors (EPIs) piperine and 1-(1-naphthylmethyl)-piperazine (NMP) inhibited biofilm formation and the expression of the Rv1217c and Rv1218c genes in a concentration-dependent manner, respectively, indicating Rv1217c and Rv1218c are potential target genes of M. tuberculosis biofilm. This study is the first RNA-Seq-based transcriptome profiling of M. tuberculosis biofilms and provides insights into a potential strategy for M. tuberculosis biofilm inhibition. KEY POINTS: • Characterize M. tuberculosis transcriptomes in biofilm cells by RNA-seq. • Inhibit the expression of Rv1217c and Rv1218c repressed biofilm formation.
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Affiliation(s)
- Fangxue Ma
- Key Laboratory for Zoonoses Research, Ministry of Education, Institute of Zoonosis, Department of Infectious Diseases, First Hospital of Jilin University, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Hong Zhou
- Key Laboratory for Zoonoses Research, Ministry of Education, Institute of Zoonosis, Department of Infectious Diseases, First Hospital of Jilin University, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Zhiqiang Yang
- Institute of Biomedical Sciences, School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Chao Wang
- Department of Immunology, Binzhou Medical University, Yantai, 264000, China
| | - Yanan An
- Department of Physiology, Binzhou Medical University, Yantai, 264000, China
| | - Lihui Ni
- Key Laboratory for Zoonoses Research, Ministry of Education, Institute of Zoonosis, Department of Infectious Diseases, First Hospital of Jilin University, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Mingyuan Liu
- Key Laboratory for Zoonoses Research, Ministry of Education, Institute of Zoonosis, Department of Infectious Diseases, First Hospital of Jilin University, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China
| | - Yang Wang
- Key Laboratory for Zoonoses Research, Ministry of Education, Institute of Zoonosis, Department of Infectious Diseases, First Hospital of Jilin University, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
| | - Lu Yu
- Key Laboratory for Zoonoses Research, Ministry of Education, Institute of Zoonosis, Department of Infectious Diseases, First Hospital of Jilin University, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
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Shahmoradi S, Shariati A, Zargar N, Yadegari Z, Asnaashari M, Amini SM, Darban-Sarokhalil D. Antimicrobial effects of selenium nanoparticles in combination with photodynamic therapy against Enterococcus faecalis biofilm. Photodiagnosis Photodyn Ther 2021; 35:102398. [PMID: 34133959 DOI: 10.1016/j.pdpdt.2021.102398] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND Selenium Nanoparticles (SeNPs) were reported as an agent that may enhance the effectiveness of Photodynamic Antimicrobial Chemotherapy (PACT). This in vitro study evaluates the effect of SeNPs on the efficacy of Methylene Blue (MB)-induced PACT against the biofilm formated in 96-well plates and the dentine tubule biofilm of Enterococcus faecalis. METHODS Chitosan coated SeNPs were synthesized using chemical reduction method and were characterized by Transmission Electron Microscope (TEM) and Dynamic Light Scattering (DLS). Twenty-four-hour biofilms of E. faecalis were developed on 96-well plates and treated with SeNPs, MB, and Light-Emitting Diode (LED). Also, three-week biofilms of E. faecalis were formed on 67 specimens of dentinal tubules, and the antibacterial effects of MB+SeNPs on these biofilms were studied. RESULTS The average hydrodynamic diameter of SeNPs was 80/3 nm according to DLS measurement. The combined use of MB and SeNPs significantly reduced Colony-Forming Units (CFUs) of one-day-old E. faecalis biofilms in comparison with the control group (P value < 0.05). Besides, combination therapy had the most antibacterial effect on root canal E. faecalis biofilms at both 200 and 400 µm depths of dentine tubules (P value < 0.001). Of note, about 50% of human fibroblast cells survived at a concentration of 128 µg/ml of SeNPs, compared to the control group. CONCLUSION The results demonstrated that the photodynamic therapy modified by SeNPs could be an effective disinfection alternative to the destruction of E. faecalis biofilms and root canal treatment.
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Affiliation(s)
- Samane Shahmoradi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Aref Shariati
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Nazanin Zargar
- School of Dentistry, Shahid Beheshti University of Medical sciences, Tehran, Iran
| | - Zahra Yadegari
- Department of Dental Biomaterials, Dental school, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Asnaashari
- Department of Endodontics, Laser Application in Medical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Mohammad Amini
- Radiation Biology Research center, Iran university of medical sciences, Tehran, Iran.
| | - Davood Darban-Sarokhalil
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Microbial Biotechnology Research Center, Iran University of Medical Sciences, Tehran, Iran.
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Fairweather SJ, Gupta V, Chitsaz M, Booth L, Brown MH, O’Mara ML. Coordination of Substrate Binding and Protonation in the N. gonorrhoeae MtrD Efflux Pump Controls the Functionally Rotating Transport Mechanism. ACS Infect Dis 2021; 7:1833-1847. [PMID: 33980014 DOI: 10.1021/acsinfecdis.1c00149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multidrug resistance is a serious problem that threatens the effective treatment of the widespread sexually transmitted disease gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae. The drug efflux pump primarily implicated in N. gonorrhoeae antimicrobial resistance is the inner membrane transporter MtrD, which forms part of the tripartite multiple transferable resistance (Mtr) CDE efflux system. A structure of MtrD was first solved in 2014 as a symmetrical homotrimer, and then, recently, as an asymmetrical homotrimer. Through a series of molecular dynamics simulations and mutagenesis experiments, we identify the combination of substrate binding and protonation states of the proton relay network that drives the transition from the symmetric to the asymmetric conformation of MtrD. We characterize the allosteric coupling between the functionally important local regions that control conformational changes between the access, binding, and extrusion states and allow for transition to the asymmetric MtrD conformation. We also highlight a significant rotation of the transmembrane helices caused by protonation of the proton relay network, which widens the intermonomeric gap that is a hallmark of the rotational transporter mechanism. This is the first analysis and description of the transport mechanism for the N. gonorrhoeae MtrD transporter and provides evidence that antimicrobial efflux in MtrD follows the functionally rotating transport mechanism seen in protein homologues from the same transport protein superfamily.
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Affiliation(s)
- Stephen J. Fairweather
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Vrinda Gupta
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Mohsen Chitsaz
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Lauren Booth
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Megan L. O’Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
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Wang X, Wang Y, Ling N, Shen Y, Zhang D, Liu D, Ou D, Wu Q, Ye Y. Effects of tolC on tolerance to bile salts and biofilm formation in Cronobacter malonaticus. J Dairy Sci 2021; 104:9521-9531. [PMID: 34099300 DOI: 10.3168/jds.2021-20128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/29/2021] [Indexed: 12/21/2022]
Abstract
Bile salts is one of essential components of bile secreted into the intestine to confer antibacterial protection. Cronobacter species are associated with necrotizing enterocolitis in newborns and show a strong tolerance to bile salts. However, little attempt has been made to focus on the molecular basis of the tolerance to bile salts. In this study, we investigated the roles of tolC on growth, cell morphology, motility, and biofilm formation ability in Cronobacter malonaticus under bile salt stress. The results indicated that the absence of tolC significantly affected the colony morphology and outer membrane structure in a normal situation, compared with those of the wild type strain. The deletion of tolC caused the decline in resistance to bile salt stress, inhibition of growth, and observable reduction in relative growth rate and motility. Moreover, the bacterial stress response promoted the biofilm formation ability of the mutant strain. The expression of the AcrAB-TolC system (acrA, acrB, and tolC) was effectively upregulated compared with the control sample when exposed to different bile salt concentrations. The findings provide valuable information for deeply understanding molecular mechanisms about the roles of tolC under bile salt stress and the prevention and control of C. malonaticus.
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Affiliation(s)
- Xin Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yaping Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Na Ling
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yizhong Shen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Danfeng Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dengyu Liu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dexin Ou
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
| | - Yingwang Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China.
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Resistance to widely-used disinfectants and heavy metals and cross resistance to antibiotics in Escherichia coli isolated from pigs, pork and pig carcass. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.107892] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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73
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Azargun R, Gholizadeh P, Sadeghi V, Hosainzadegan H, Tarhriz V, Memar MY, Pormohammad A, Eyvazi S. Molecular mechanisms associated with quinolone resistance in Enterobacteriaceae: review and update. Trans R Soc Trop Med Hyg 2021; 114:770-781. [PMID: 32609840 DOI: 10.1093/trstmh/traa041] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 04/09/2020] [Accepted: 05/20/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Quinolones are broad-spectrum antibiotics, which are used for the treatment of different infectious diseases associated with Enterobacteriaceae. During recent decades, the wide use as well as overuse of quinolones against diverse infections has led to the emergence of quinolone-resistant bacterial strains. Herein, we present the development of quinolone antibiotics, their function and also the different quinolone resistance mechanisms in Enterobacteriaceae by reviewing recent literature. METHODS All data were extracted from Google Scholar search engine and PubMed site, using keywords; quinolone resistance, Enterobacteriaceae, plasmid-mediated quinolone resistance, etc. RESULTS AND CONCLUSION The acquisition of resistance to quinolones is a complex and multifactorial process. The main resistance mechanisms consist of one or a combination of target-site gene mutations altering the drug-binding affinity of target enzymes. Other mechanisms of quinolone resistance are overexpression of AcrAB-tolC multidrug-resistant efflux pumps and downexpression of porins as well as plasmid-encoded resistance proteins including Qnr protection proteins, aminoglycoside acetyltransferase (AAC(6')-Ib-cr) and plasmid-encoded active efflux pumps such as OqxAB and QepA. The elucidation of resistance mechanisms will help researchers to explore new drugs against the resistant strains.
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Affiliation(s)
- Robab Azargun
- Department of Microbiology, Faculty of Medicine, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Pourya Gholizadeh
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vahid Sadeghi
- Faculty of Veterinary Medicine, Islamic Azad University, Urmia, Iran
| | - Hasan Hosainzadegan
- Department of Microbiology, Faculty of Medicine, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Vahideh Tarhriz
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Pormohammad
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shirin Eyvazi
- Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Durães F, Resende DISP, Palmeira A, Szemerédi N, Pinto MMM, Spengler G, Sousa E. Xanthones Active against Multidrug Resistance and Virulence Mechanisms of Bacteria. Antibiotics (Basel) 2021; 10:600. [PMID: 34069329 PMCID: PMC8158687 DOI: 10.3390/antibiotics10050600] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/28/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023] Open
Abstract
The emergence of multidrug and extensively drug-resistant pathogenic bacteria able to resist to the action of a wide range of antibiotics is becoming a growing problem for public health. The search for new compounds with the potential to help in the reversion of bacterial resistance plays an important role in current medicinal chemistry research. Under this scope, bacterial efflux pumps are responsible for the efflux of antimicrobials, and their inhibition could reverse resistance. In this study, the multidrug resistance reversing activity of a series of xanthones was investigated. Firstly, docking studies were performed in the AcrAB-TolC efflux pump and in a homology model of the NorA pump. Then, the effects of twenty xanthone derivatives on bacterial growth were evaluated in Staphylococcus aureus 272123 and in the acrA gene-inactivated mutant Salmonella enterica serovar Typhimurium SL1344 (SE03). Their efflux pump inhibitory properties were assessed using real-time fluorimetry. Assays concerning the activity of these compounds towards the inhibition of biofilm formation and quorum sensing have also been performed. Results showed that a halogenated phenylmethanamine xanthone derivative displayed an interesting profile, as far as efflux pump inhibition and biofilm formation were concerned. To the best of our knowledge, this is the first report of xanthones as potential efflux pump inhibitors.
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Affiliation(s)
- Fernando Durães
- Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (F.D.); (D.I.S.P.R.); (A.P.); (M.M.M.P.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Diana I. S. P. Resende
- Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (F.D.); (D.I.S.P.R.); (A.P.); (M.M.M.P.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Andreia Palmeira
- Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (F.D.); (D.I.S.P.R.); (A.P.); (M.M.M.P.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Nikoletta Szemerédi
- Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Faculty of Medicine, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary;
| | - Madalena M. M. Pinto
- Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (F.D.); (D.I.S.P.R.); (A.P.); (M.M.M.P.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Gabriella Spengler
- Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Faculty of Medicine, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary;
| | - Emília Sousa
- Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; (F.D.); (D.I.S.P.R.); (A.P.); (M.M.M.P.)
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
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75
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Alav I, Kobylka J, Kuth MS, Pos KM, Picard M, Blair JMA, Bavro VN. Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria. Chem Rev 2021; 121:5479-5596. [PMID: 33909410 PMCID: PMC8277102 DOI: 10.1021/acs.chemrev.1c00055] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components-the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.
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Affiliation(s)
- Ilyas Alav
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jessica Kobylka
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Miriam S. Kuth
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Klaas M. Pos
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Martin Picard
- Laboratoire
de Biologie Physico-Chimique des Protéines Membranaires, CNRS
UMR 7099, Université de Paris, 75005 Paris, France
- Fondation
Edmond de Rothschild pour le développement de la recherche
Scientifique, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jessica M. A. Blair
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Vassiliy N. Bavro
- School
of Life Sciences, University of Essex, Colchester, CO4 3SQ United Kingdom
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76
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Anandamide alters the membrane properties, halts the cell division and prevents drug efflux in multidrug resistant Staphylococcus aureus. Sci Rep 2021; 11:8690. [PMID: 33888802 PMCID: PMC8062478 DOI: 10.1038/s41598-021-88099-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/08/2021] [Indexed: 02/02/2023] Open
Abstract
Antibiotic resistance is a serious public health problem throughout the world. Overcoming methicillin and multidrug-resistant Staphylococcus aureus (MRSA/MDRSA) infections has become a challenge and there is an urgent need for new therapeutic approaches. We have previously demonstrated that the endocannabinoid Anandamide (AEA) can sensitize MRSA to antibiotics. Here we have studied the mechanism of action using a MDRSA clinical isolate that are sensitized by AEA to methicillin and norfloxacin. We found that AEA treatment halts the growth of both antibiotic-sensitive and antibiotic-resistant S. aureus. The AEA-treated bacteria become elongated and the membranes become ruffled with many protrusions. AEA treatment also leads to an increase in the percentage of bacteria having a complete septum, suggesting that the cell division is halted at this stage. The latter is supported by cell cycle analysis that shows an accumulation of bacteria in the G2/M phase after AEA treatment. We further observed that AEA causes a dose-dependent membrane depolarization that is partly relieved upon time. Nile red staining of the bacterial membranes indicates that AEA alters the membrane structures. Importantly, 4'-6-diamidino-2-phenylindole (DAPI) accumulation assay and ethidium bromide efflux (EtBr) assay unveiled that AEA leads to a dose-dependent drug accumulation by inhibiting drug efflux. In conclusion, our study demonstrates that AEA interferes with cell division, alters the membrane properties of MDRSA, and leads to increased intracellular drug retention, which can contribute to the sensitization of MDRSA to antibiotics.
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77
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The ABC-Type Efflux Pump MacAB Is Involved in Protection of Serratia marcescens against Aminoglycoside Antibiotics, Polymyxins, and Oxidative Stress. mSphere 2021; 6:6/2/e00033-21. [PMID: 33692192 PMCID: PMC8546677 DOI: 10.1128/msphere.00033-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Serratia marcescens is an emerging pathogen with increasing clinical importance due to its intrinsic resistance to several classes of antibiotics. The chromosomally encoded drug efflux pumps contribute to antibiotic resistance and represent a major challenge for the treatment of bacterial infections. The ABC-type efflux pump MacAB was previously linked to macrolide resistance in Escherichia coli and Salmonella enterica serovar Typhimurium. The role of the MacAB homolog in antibiotic resistance of S. marcescens is currently unknown. We found that an S. marcescens mutant lacking the MacAB pump did not show increased sensitivity to the macrolide antibiotic erythromycin but was significantly more sensitive to aminoglycoside antibiotics and polymyxins. We also showed that, in addition to its role in drug efflux, the MacAB efflux pump is required for swimming motility and biofilm formation. We propose that the motility defect of the ΔmacAB mutant is due, at least in part, to the loss of functional flagella on the bacterial surface. Furthermore, we found that the promoter of the MacAB efflux pump was active during the initial hours of growth in laboratory medium and that its activity was further elevated in the presence of hydrogen peroxide. Finally, we demonstrate a complete loss of ΔmacAB mutant viability in the presence of peroxide, which is fully restored by complementation. Thus, the S. marcescens MacAB efflux pump is essential for survival during oxidative stress and is involved in protection from polymyxins and aminoglycoside antibiotics. IMPORTANCE The opportunistic pathogen Serratia marcescens can cause urinary tract infections, respiratory infections, meningitis, and sepsis in immunocompromised individuals. These infections are challenging to treat due to the intrinsic resistance of S. marcescens to an extensive array of antibiotics. Efflux pumps play a crucial role in protection of bacteria from antimicrobials. The MacAB efflux pump, previously linked to efflux of macrolides in Escherichia coli and protection from oxidative stress in Salmonella enterica serovar Typhimurium, is not characterized in S. marcescens. We show the role of the MacAB efflux pump in S. marcescens protection from aminoglycoside antibiotics and polymyxins, modulation of bacterial motility, and biofilm formation, and we illustrate the essential role for this pump in bacterial survival during oxidative stress. Our findings make the MacAB efflux pump an attractive target for inhibition to gain control over S. marcescens infections.
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78
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Anokwah D, Asante-Kwatia E, Mensah AY, Danquah CA, Harley BK, Amponsah IK, Oberer L. Bioactive constituents with antibacterial, resistance modulation, anti-biofilm formation and efflux pump inhibition properties from Aidia genipiflora stem bark. CLINICAL PHYTOSCIENCE 2021. [DOI: 10.1186/s40816-021-00266-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Antimicrobial resistance is a global health challenge. The involvement of bacterial biofilms and efflux pumps in the development of multidrug resistance (MDR) is well established. Medicinal plants have been proposed as alternatives for combating MDR focusing on their bioactive constituents with resistance modulatory activities. This study was aimed at investigating the stem bark of Aidia genipiflora for bioactive constituents with anti-biofilm, efflux pump inhibition and resistance modulatory activities.
Method
The crude methanol extract was purified by column chromatography and isolated compounds characterized by mass and nuclear magnetic resonance spectrometry. Antibacterial activity was determined by the High-throughput spot culture growth inhibition and the broth micro-dilution assay. The ethidium bromide accumulation assay was used to determine efflux pump inhibition property. Biofilm inhibition was determined in a microplate crystal violet retention assay.
Results
Purification of the ethyl acetate fraction led to the isolation of oleanonic acid (1), 4-hydroxy cinnamic acid docosyl ester (2), β-stigmasterol/β-sitosterol (mixture 3a/b) and D-mannitol (4). The minimum inhibitory concentrations (MICs) ranged from 250 to > 500 μg/mL for extracts and fractions and from 15 to 250 μg/mL for compounds. In the presence of sub-inhibitory concentrations of the compounds, the MIC of amoxicillin against E. coli (20 μg/mL) and P. aeruginosa (320 μg/mL) was reduced by 32 and 10 folds respectively. The whole extract demonstrated anti-biofilm formation and efflux pump inhibition in E. coli, S. aureus and P. aeruginosa. The sterol mixture (3a/b) at concentration of 100 μg/mL caused the highest inhibition (73%) of biofilm formation in S. aureus. Oleanonic acid (1) demonstrated remarkable efflux pump inhibition at MIC of 7.8 μg/mL in E. coli better than the standard drugs verapamil and chlorpromazine.
Conclusion
This study confirms the prospects of A. genipiflora as a source of new antibacterial agents and adjuvants that could interact with some resistance mechanisms in bacteria to enhance the activity of hitherto ineffective antibiotics. “A small portion of the study has been presented in a conference in the form of poster”.
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79
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Antibiofilm activity of Fmoc-phenylalanine against Gram-positive and Gram-negative bacterial biofilms. J Antibiot (Tokyo) 2021; 74:407-416. [PMID: 33637856 DOI: 10.1038/s41429-021-00409-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 11/08/2022]
Abstract
Biofilm associated infections are the major contributor of mortality, morbidity and financial burden in patients with a bacterial infection. About 65% of all bacterial infections are associated with the information of bacterial biofilms. Bacterial biofilms not only reduce the efficacy of antibacterial treatment but also increases the threat of developing antibacterial resistance. Recently, our group has discovered the antibacterial activity of Fmoc-phenylalanine (Fmoc-F) and other Fmoc-amino acids (Fmoc-AA). Fmoc-F and other Fmoc-AA showed antibacterial activity due to their surfactant properties. Surfactants are known to eradicate biofilm and enhance antimicrobial activity in biofilm. Thus, in the present study, we evaluated the anti-biofilm activity of Fmoc-F against clinically relevant bacteria. We found that Fmoc-F not only inhibits the biofilm formation in Staphylococcus aureus and Pseudomonas aeruginosa, but also eradicates the already formed biofilms over the surface. Further, Fmoc-F coated glass surface resists S. aureus and P. aeruginosa biofilm formation and attachment, when biofilm is grown over the surface. The mechanistic investigation suggests that Fmoc-F reduces the extracellular matrix (ECM) components such as proteins, carbohydrates and eDNA in the biofilm and affect its stability via direct interactions with ECM components and/ or indirectly through reducing bacterial cell population. Finally, we showed that Fmoc-F treatment in combination with vancomycin and ampicillin synergistically inhibit biofilm formation. Overall, the study demonstrates the potential application of Fmoc-F and other Fmoc-AA molecules individually as well as in combination as anti-biofilm coating material for treating biofilm associated infections.
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80
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Biofunctionalization of Poly(lactide- co-glycolic acid) Using Potent NorA Efflux Pump Inhibitors Immobilized on Nanometric Alpha-Zirconium Phosphate to Reduce Biofilm Formation. MATERIALS 2021; 14:ma14030670. [PMID: 33535577 PMCID: PMC7867184 DOI: 10.3390/ma14030670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 12/29/2022]
Abstract
Polymeric composites, where bioactive species are immobilized on inorganic nanostructured matrix, have received considerable attention as surfaces able to reduce bacterial adherence, colonization, and biofilm formation in implanted medical devices. In this work, potent in-house S. aureus NorA efflux pump inhibitors (EPIs), belonging to the 2-phenylquinoline class, were immobilized on nanometric alpha-zirconium phosphate (ZrP) taking into advantage of acid-base or intercalation reactions. The ZrP/EPI were used as filler of poly(lactide-co-glycolic acid) (PLGA) to obtain film composites with a homogeneous distribution of the ZrP/EPI fillers. As reference, PLGA films loaded with ZrP intercalated with thioridazine (TZ), that is recognized as both a NorA and biofilm inhibitor, and with the antibiotic ciprofloxacin (CPX) were prepared. Composite films were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The ability of the composite films, containing ZrP/EPI, to inhibit biofilm formation was tested on Staphylococcus aureus ATCC 29213 and Staphylococcus epidermidis ATCC 12228, and it was compared with that of the composite loaded with ZrP/TZ. Finally, the antibacterial activity of CPX intercalated in ZrP was evaluated when used in combination with ZrP/EPI in the PLGA films.
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81
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Biofilms as Promoters of Bacterial Antibiotic Resistance and Tolerance. Antibiotics (Basel) 2020; 10:antibiotics10010003. [PMID: 33374551 PMCID: PMC7822488 DOI: 10.3390/antibiotics10010003] [Citation(s) in RCA: 184] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/15/2020] [Accepted: 12/19/2020] [Indexed: 12/12/2022] Open
Abstract
Multidrug resistant bacteria are a global threat for human and animal health. However, they are only part of the problem of antibiotic failure. Another bacterial strategy that contributes to their capacity to withstand antimicrobials is the formation of biofilms. Biofilms are associations of microorganisms embedded a self-produced extracellular matrix. They create particular environments that confer bacterial tolerance and resistance to antibiotics by different mechanisms that depend upon factors such as biofilm composition, architecture, the stage of biofilm development, and growth conditions. The biofilm structure hinders the penetration of antibiotics and may prevent the accumulation of bactericidal concentrations throughout the entire biofilm. In addition, gradients of dispersion of nutrients and oxygen within the biofilm generate different metabolic states of individual cells and favor the development of antibiotic tolerance and bacterial persistence. Furthermore, antimicrobial resistance may develop within biofilms through a variety of mechanisms. The expression of efflux pumps may be induced in various parts of the biofilm and the mutation frequency is induced, while the presence of extracellular DNA and the close contact between cells favor horizontal gene transfer. A deep understanding of the mechanisms by which biofilms cause tolerance/resistance to antibiotics helps to develop novel strategies to fight these infections.
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82
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Targeting bioenergetics is key to counteracting the drug-tolerant state of biofilm-grown bacteria. PLoS Pathog 2020; 16:e1009126. [PMID: 33351859 PMCID: PMC7787680 DOI: 10.1371/journal.ppat.1009126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 01/06/2021] [Accepted: 11/05/2020] [Indexed: 12/30/2022] Open
Abstract
Embedded in an extracellular matrix, biofilm-residing bacteria are protected from diverse physicochemical insults. In accordance, in the human host the general recalcitrance of biofilm-grown bacteria hinders successful eradication of chronic, biofilm-associated infections. In this study, we demonstrate that upon addition of promethazine, an FDA approved drug, antibiotic tolerance of in vitro biofilm-grown bacteria can be abolished. We show that following the addition of promethazine, diverse antibiotics are capable of efficiently killing biofilm-residing cells at minimal inhibitory concentrations. Synergistic effects could also be observed in a murine in vivo model system. PMZ was shown to increase membrane potential and interfere with bacterial respiration. Of note, antibiotic killing activity was elevated when PMZ was added to cells grown under environmental conditions that induce low intracellular proton levels. Our results imply that biofilm-grown bacteria avoid antibiotic killing and become tolerant by counteracting intracellular alkalization through the adaptation of metabolic and transport functions. Abrogation of antibiotic tolerance by interfering with the cell’s bioenergetics promises to pave the way for successful eradication of biofilm-associated infections. Repurposing promethazine as a biofilm-sensitizing drug has the potential to accelerate the introduction of new treatments for recalcitrant, biofilm-associated infections into the clinic. At sub-minimal inhibitory concentrations, phenothiazines have been shown to inhibit virulence as well as the formation of biofilms in a wide range of different bacterial pathogens. In this study, we analyzed the anti-bacterial effect of the FDA-approved drug, promethazine, on biofilm-grown Pseudomonas aeruginosa. We demonstrate that PMZ interferes with bacterial bioenergetics and sensitizes biofilm-grown P. aeruginosa cells to bactericidal activity of several different classes of antibiotics by several orders of magnitude. This effect was most pronounced when cells were grown under environmental conditions that induce low intracellular proton levels. Thus, it seems that a reduced proton efflux in cells that exhibit decreased respiratory activity due to their biofilm mode of growth might explain their general antimicrobial tolerance. The use of PMZ as an antibiotic sensitizer holds promise that targeting tolerance mechanisms of biofilm-grown bacteria could become a practicable way to change the way physicians treat biofilm-associated infections.
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83
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Teo SP, Bhakta S, Stapleton P, Gibbons S. Bioactive Compounds from the Bornean Endemic Plant Goniothalamus longistipetes. Antibiotics (Basel) 2020; 9:antibiotics9120913. [PMID: 33339285 PMCID: PMC7767169 DOI: 10.3390/antibiotics9120913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/08/2020] [Accepted: 12/15/2020] [Indexed: 11/24/2022] Open
Abstract
The present study aimed to screen plants for bioactive compounds with potential antibacterial activities. In our efforts to evaluate plants from Borneo, we isolated and elucidated the structures of four natural products from the bioactive fraction of a chloroform extract of Goniothalamus longistipetes using various chromatographic and spectroscopic techniques. The bioactive compounds were identified as a known styryllactone, (+)-altholactone ((2S,3R,3aS,7aS)-3-hydroxy-2-phenyl-2,3,3a,7a-tetrahydrobenzo-5(4H)-5-one) (1), a new styryllactone, (2S,3R,3aS,7aS)-3-hydroxy-2-phenyl-2,3,3a,7a-tetrahydrobenzo-5(4H)-5-one) (2) as well as a new alkaloid, 2,6-dimethoxyisonicotinaldehyde (3) and a new alkenyl-5-hydroxyl-phenyl benzoic acid (4). 1 and 4 showed broad-spectrum anti-bacterial activities against Gram-positive and Gram-negative bacteria as well as acid-fast model selected for this study. Compound 2 only demonstrated activities against Gram-positive bacteria whilst 3 displayed selective inhibitory activities against Gram-positive bacterial strains. Additionally, their mechanisms of anti-bacterial action were also investigated. Using Mycobacterium smegmatis as a fast-growing model of tubercle bacilli, compounds 1, 2 and 4 demonstrated inhibitory activities against whole-cell drug efflux and biofilm formation; two key intrinsic mechanisms of antibiotic resistance. Interestingly, the amphiphilic compound 4 exhibited inhibitory activity against the conjugation of plasmid pKM101 in Escherichia coli using a plate conjugation assay. Plasmid conjugation is a mechanism by which Gram-positive and Gram-negative-bacteria acquire drug resistance and virulence. These results indicated that bioactive compounds isolated from Goniothalamus longistipetes can be potential candidates as ‘hits’ for further optimisation.
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Affiliation(s)
- Stephen P. Teo
- Research Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK; (P.S.); (S.G.)
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK;
- Forest Department Sarawak, Wisma Sumber Alam, Petra Jaya, Kuching 93600, Malaysia
- Correspondence:
| | - Sanjib Bhakta
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK;
| | - Paul Stapleton
- Research Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK; (P.S.); (S.G.)
| | - Simon Gibbons
- Research Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK; (P.S.); (S.G.)
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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84
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Khan S, Khan SN, Akhtar F, Misba L, Meena R, Khan AU. Inhibition of multi-drug resistant Klebsiella pneumoniae: Nanoparticles induced photoinactivation in presence of efflux pump inhibitor. Eur J Pharm Biopharm 2020; 157:165-174. [DOI: 10.1016/j.ejpb.2020.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 01/08/2023]
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85
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Jesin JA, Stone TA, Mitchell CJ, Reading E, Deber CM. Peptide-Based Approach to Inhibition of the Multidrug Resistance Efflux Pump AcrB. Biochemistry 2020; 59:3973-3981. [PMID: 33026802 DOI: 10.1021/acs.biochem.0c00417] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Clinically relevant multidrug-resistant bacteria often arise due to overproduction of membrane-embedded efflux proteins that are capable of pumping antibiotics out of the bacterial cell before the drugs can exert their intended toxic effect. The Escherichia coli membrane protein AcrB is the archetypal protein utilized for bacterial efflux study because it can extrude a diverse range of antibiotic substrates and has close homologues in many Gram-negative pathogens. Three AcrB subunits, each of which contains 12 transmembrane (TM) helices, are known to trimerize to form the minimal functional unit, stabilized noncovalently by helix-helix interactions between TM1 and TM8. To inhibit the efflux activity of AcrB, we have rationally designed synthetic peptides aimed at destabilizing the AcrB trimerization interface by outcompeting the subunit interaction sites within the membrane. Here we report that peptides mimicking TM1 or TM8, with flanking N-terminal peptoid tags, and C-terminal lysine tags that aid in directing the peptides to their membrane-embedded target, decrease the AcrB-mediated efflux of the fluorescent substrate Nile red and potentiate the effect of the antimicrobials chloramphenicol and ethidium bromide. To further characterize the motif encompassing the interaction between TM1 and TM8, we used Förster resonance energy transfer to demonstrate dimerization. Using the TM1 and TM8 peptides, in conjunction with several selected mutant peptides, we highlight residues that may increase the potency and specificity of the peptide drug candidates. In targeting membrane-embedded protein-protein interactions, this work represents a novel approach to AcrB inhibition and, more broadly, a potential route to a new category of efflux pump inhibitors.
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Affiliation(s)
- Joshua A Jesin
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Ontario, Canada
| | - Tracy A Stone
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Ontario, Canada
| | - Chloe J Mitchell
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Ontario, Canada
| | - Eamonn Reading
- Department of Chemistry, Britannia House, King's College London, 7 Trinity Street, London SE1 1DB, United Kingdom
| | - Charles M Deber
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto M5G 0A4, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto M5S 1A8, Ontario, Canada
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86
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AlMatar M, Albarri O, Makky EA, Köksal F. Efflux pump inhibitors: new updates. Pharmacol Rep 2020; 73:1-16. [PMID: 32946075 DOI: 10.1007/s43440-020-00160-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/17/2022]
Abstract
The discovery of antibiotics ought to have ended the issue of bacterial infections, but this was not the case as it has led to the evolution of various mechanisms of bacterial resistance against various antibiotics. The efflux pump remains one of the mechanisms through which organisms develop resistance against antibiotics; this is because organisms can extrude most of the clinically relevant antibiotics from the interior cell environment to the exterior environment via the efflux pumps. Efflux pumps are thought to contribute significantly to biofilm formation as highlighted by various studies. Therefore, the inhibition of these efflux pumps can be a potential way of improving the activity of antibiotics, particularly now that the discovery of novel antibiotics is becoming tedious. Efflux pump inhibitors (EPIs) are molecules that can inhibit efflux pumps; they have been considered potential therapeutic agents for rejuvenating the activity of antibiotics that have already lost their activity against bacteria. However, studies are yet to determine the specific substrates for such pumps; the effect of altered efflux activity of these pumps on biofilm formation is still being investigated. A clear knowledge of the involvement of efflux pumps in biofilm development could aid in developing new agents that can interfere with their function and help to prevent biofilms formation; thereby, improving the outcome of treatment strategies. This review focuses on the novel update of EPIs and discusses the evidence of the roles of efflux pumps in biofilm formation; the potential approaches towards overcoming the increasing problem of biofilm-based infections are also discussed.
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Affiliation(s)
- Manaf AlMatar
- Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang (UMP), 26300, Gambang, Kuantan, Malaysia.
| | - Osman Albarri
- Department of Biotechnology, Institute of Natural and Applied Sciences (Fen Bilimleri Enstitüsü), Çukurova University, Adana, Turkey
| | - Essam A Makky
- Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang (UMP), 26300, Gambang, Kuantan, Malaysia.
| | - Fatih Köksal
- Department of Medical Microbiology, Faculty of Medicine, Çukurova University, Adana, Turkey
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87
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Cai Y, Wang C, Chen Z, Xu Z, Li H, Li W, Sun Y. Transporters HP0939, HP0497, and HP0471 participate in intrinsic multidrug resistance and biofilm formation in Helicobacter pylori by enhancing drug efflux. Helicobacter 2020; 25:e12715. [PMID: 32548895 DOI: 10.1111/hel.12715] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/17/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND The multidrug resistance of Helicobacter pylori is becoming an increasingly serious issue. It is therefore necessary to study the mechanism of multidrug resistance of H pylori. We have previously identified that the HP0939, HP0497, and HP0471 transporters affect the efflux of drugs from H pylori. As efflux pumps participate in bacterial multidrug resistance and biofilm formation, we hypothesized that these transporters could be involved in the multidrug resistance and biofilm formation of H pylori. MATERIALS AND METHODS We therefore constructed three knockout strains, Δhp0939, Δhp0497, and Δhp0471, and three high-expression strains, Hp0939he , Hp0497he , and Hp0471he , using the wild-type (WT) 26 695 strain of H pylori as the template. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of wild strains, knockout strains, and high-expression strains to amoxicillin, metronidazole, and other antibiotics were measured. The efflux capacity of high-expression strains and wild strains was compared by Hoechst 33 342 accumulation assay. RESULTS Determination of the MIC and MBC of the antibiotics revealed that the knockout strains were more sensitive to antibiotics, while the high-expression strains were less sensitive to antibiotics, compared to the WT. The ability of the high-expression strains to efflux drugs was significantly higher than that of the WT. We also induced H pylori to form biofilms, and observed that the knockout strains could barely form biofilms and were more sensitive to several antibiotics, compared to the WT. The mRNA expression of hp0939, hp0497, and hp0471 in the clinically sensitive and multidrug-resistant strains was determined, and it was found that these genes were highly expressed in the multidrug-resistant strains that were isolated from the clinics. CONCLUSIONS In this study, we found three transporters involved in intrinsic multidrug resistance of H pylori.
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Affiliation(s)
- Yuying Cai
- Department of Microbiology, Key Laboratory of Medical Microbiology and Parasitology, Guizhou Medical University, Guiyang, China.,Institute of Pathogen Biology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Caixia Wang
- Department of Microbiology, Key Laboratory of Medical Microbiology and Parasitology, Guizhou Medical University, Guiyang, China.,Institute of Pathogen Biology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Zhenghong Chen
- Department of Microbiology, Key Laboratory of Medical Microbiology and Parasitology, Guizhou Medical University, Guiyang, China
| | - Zhengzheng Xu
- Department of Microbiology, Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunology of Shandong Province, School of Basic Medicine, Shandong University, Jinan, China
| | - Huanjie Li
- Department of Microbiology, Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunology of Shandong Province, School of Basic Medicine, Shandong University, Jinan, China
| | - Wenjuan Li
- Department of Microbiology, Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunology of Shandong Province, School of Basic Medicine, Shandong University, Jinan, China
| | - Yundong Sun
- Department of Microbiology, Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunology of Shandong Province, School of Basic Medicine, Shandong University, Jinan, China
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88
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Grimsey EM, Piddock LJV. Do phenothiazines possess antimicrobial and efflux inhibitory properties? FEMS Microbiol Rev 2020; 43:577-590. [PMID: 31216574 DOI: 10.1093/femsre/fuz017] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 06/12/2019] [Indexed: 12/30/2022] Open
Abstract
Antibiotic resistance is a global health concern; the rise of drug-resistant bacterial infections is compromising the medical advances that resulted from the introduction of antibiotics at the beginning of the 20th century. Considering that the presence of mutations within individuals in a bacterial population may allow a subsection to survive and propagate in response to selective pressure, as long as antibiotics are used in the treatment of bacterial infections, development of resistance is an inevitable evolutionary outcome. This, combined with the lack of novel antibiotics being released to the clinical market, means the need to develop alternative strategies to treat these resistant infections is critical. We discuss how the use of antibiotic adjuvants can minimise the appearance and impact of resistance. To this effect, several phenothiazine-derived drugs have been shown to potentiate the activities of antibiotics used to treat infections caused by Gram-positive and Gram-negative bacteria. Outside of their role as antipsychotic medications, we review the evidence to suggest that phenothiazines possess inherent antibacterial and efflux inhibitory properties enabling them to potentially combat drug resistance. We also discuss that understanding their mode of action is essential to facilitate the design of new phenothiazine derivatives or novel agents for use as antibiotic adjuvants.
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Affiliation(s)
- Elizabeth M Grimsey
- Institute of Microbiology & Infection, College of Medical & Dental Sciences, University of Birmingham, Edgbaston, United Kingdom
| | - Laura J V Piddock
- Institute of Microbiology & Infection, College of Medical & Dental Sciences, University of Birmingham, Edgbaston, United Kingdom
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89
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A Novel Derivative of Thioridazine Shows Low Toxicity and Efficient Activity against Gram-Positive Pathogens. Antibiotics (Basel) 2020; 9:antibiotics9060327. [PMID: 32549350 PMCID: PMC7344759 DOI: 10.3390/antibiotics9060327] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 12/11/2022] Open
Abstract
Thioridazine hydrochloride (HCl) has been suggested as a promising antimicrobial helper compound for the treatment of infections with antimicrobial-resistant bacteria. Unfortunately, the therapeutic concentration of thioridazine HCl is generally higher than what can be tolerated clinically, in part due to its toxic side effects on the central nervous system. Therefore, we aimed to synthesize a less toxic thioridazine derivative that would still retain its properties as a helper compound. This resulted in a compound designated 1-methyl-2-(2-(2-(methylthio)-10H-phenothiazin-10-yl)ethyl)-1-pentylpiperidin-1-ium bromide (abbreviated T5), which exhibited low blood–brain barrier permeability. The lowest minimal inhibitory concentration (MIC) against Staphylococcus aureus exposed to the novel compound was reduced 32-fold compared to thioridazine HCl (from 32 µg/mL to 1 µg/mL). The MIC values for T5 against five Gram-positive pathogens ranged from 1 µg/mL to 8 µg/mL. In contrast to thioridazine HCl, T5 does not act synergistically with oxacillin. In silico predictive structure analysis of T5 suggests that an acceptably low toxicity and lack of induced cytotoxicity was demonstrated by a lactate dehydrogenase assay. Conclusively, T5 is suggested as a novel antimicrobial agent against Gram-positive bacteria. However, future pharmacokinetic and pharmacodynamic studies are needed to clarify the clinical potential of this novel discovery.
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90
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Verni MC, Garay JA, Mendoza L, Bardón A, Borkosky S, Arena ME, Cartagena E. Lipophilic 9,10-Dehydrofukinone Action on Pathogenic and Non-Pathogenic Bacterial Biofilms. Why Is This Main Volatile Metabolite in Senecio? Chem Biodivers 2020; 17:e1900507. [PMID: 32277597 DOI: 10.1002/cbdv.201900507] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 04/09/2020] [Indexed: 11/09/2022]
Abstract
The effect of a natural sesquiterpene ketone, 9,10-dehydrofukinone (DHF), on pathogenic Staphylococcus aureus and Pseudomonas aeruginosa strains isolated from chronic infectious processes, was the focus of the present study. Lipophilic DHF produced important antibacterial synergistic effects in association with ciprofloxacin (CPX) against two biofilm-forming strains of S. aureus HT1 (FIC=0.21) and P. aeruginosa HT5 (FIC=0.05). Hence, this mixture constitutes an excellent strategy to combat these biofilm-producing bacteria that overexpress drug efflux pumps as a resistance mechanism. Additionally, a substantial rise in beneficial Lactobacillus biofilm biomass was determined as a very significant finding of this association. Particularly, a non-pathogenic biofilm increment of 119 % was quantified when the mixture was added to a probiotic L. acidophilus ATCC SD-5212 culture. A surface activity enhanced in 71 % with respect to untreated L. acidophilus culture was also generated by the DHF and CPX association, and therefore, a glycoprotein synthesis induction mediated by the mixture is discussed. The results obtained could help in the development of new selective antibiotics. From an ecological standpoint, the present study strongly suggests that DHF is a polyfunctional organic molecule produced with a high yield in Senecio punae that exerts a positive impact on a non-pathogenic plant bacterium L. plantarum CE105.
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Affiliation(s)
- María C Verni
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina.,INBIOFAL (CONICET-UNT), Av. Kirchner 1900, Tucumán, 4000, Argentina
| | - José A Garay
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina
| | - Lucía Mendoza
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina
| | - Alicia Bardón
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina
| | - Susana Borkosky
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina
| | - Mario E Arena
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina.,INBIOFAL (CONICET-UNT), Av. Kirchner 1900, Tucumán, 4000, Argentina
| | - Elena Cartagena
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, Tucumán, 4000, Argentina.,INBIOFAL (CONICET-UNT), Av. Kirchner 1900, Tucumán, 4000, Argentina
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91
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Subhadra B, Surendran S, Lim BR, Yim JS, Kim DH, Woo K, Kim HJ, Oh MH, Choi CH. Regulation of the AcrAB efflux system by the quorum-sensing regulator AnoR in Acinetobacter nosocomialis. J Microbiol 2020; 58:507-518. [PMID: 32462488 DOI: 10.1007/s12275-020-0185-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
Multidrug efflux pumps play an important role in antimicrobial resistance and pathogenicity in bacteria. Here, we report the functional characterization of the RND (resistance-nodulation- division) efflux pump, AcrAB, in Acinetobacter nosocomialis. An in silico analysis revealed that homologues of the AcrAB efflux pump, comprising AcrA and AcrB, are widely distributed among different bacterial species. Deletion of acrA and/or acrB genes led to decreased biofilm/pellicle formation and reduced antimicrobial resistance in A. nosocomialis. RNA sequencing and mRNA expression analyses showed that expression of acrA/B was downregulated in a quorum sensing (QS) regulator (anoR)-deletion mutant, indicating transcriptional activation of the acrAB operon by AnoR in A. nosocomialis. Bioassays showed that secretion of N-acyl homoserine lactones (AHLs) was unaffected in acrA and acrB deletion mutants; however, AHL secretion was limited in a deletion mutant of acrR, encoding the acrAB regulator, AcrR. An in silico analysis indicated the presence of AcrR-binding motifs in promoter regions of anoI (encoding AHL synthase) and anoR. Specific binding of AcrR was confirmed by electrophoretic mobility shift assays, which revealed that AcrR binds to positions -214 and -217 bp upstream of the translational start sites of anoI and anoR, respectively, demonstrating transcriptional regulation of these QS genes by AcrR. The current study further addresses the possibility that AcrAB is controlled by the osmotic stress regulator, OmpR, in A. nosocomialis. Our data demonstrate that the AcrAB efflux pump plays a crucial role in biofilm/pellicle formation and antimicrobial resistance in A. nosocomialis, and is under the transcriptional control of a number of regulators. In addition, the study emphasizes the interrelationship of QS and AcrAB efflux systems in A. nosocomialis.
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Affiliation(s)
- Bindu Subhadra
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Surya Surendran
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Bo Ra Lim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Jong Sung Yim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Dong Ho Kim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Kyungho Woo
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Hwa-Jung Kim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea.,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan, 31116, Republic of Korea.
| | - Chul Hee Choi
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, 35015, Republic of Korea. .,Department of Medical Science, Chungnam National University, Daejeon, 34134, Republic of Korea.
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92
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Holden ER, Webber MA. MarA, RamA, and SoxS as Mediators of the Stress Response: Survival at a Cost. Front Microbiol 2020. [PMID: 32431683 DOI: 10.3389/fmicb.2020.0082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
To survive and adapt to changing environments, bacteria have evolved mechanisms to express appropriate genes at appropriate times. Exposure to antimicrobials triggers a global stress response in Enterobacteriaceae, underpinned by activation of a family of transcriptional regulators, including MarA, RamA, and SoxS. These control a program of altered gene expression allowing a rapid and measured response to improve fitness in the presence of toxic drugs. Increased expression of marA, ramA, and soxS up regulates efflux activity to allow detoxification of the cell. However, this also results in trade-offs in other phenotypes, such as impaired growth rates, biofilm formation and virulence. Here, we review the current knowledge regarding the trade-offs that exist between drug survival and other phenotypes that result from induction of marA, ramA, and soxS. Additionally, we present some new findings linking expression of these regulators and biofilm formation in Enterobacteriaceae, thereby demonstrating the interconnected nature of regulatory networks within the cell and explaining how trade-offs can exist between important phenotypes. This has important implications for our understanding of how bacterial virulence and biofilms can be influenced by exposure to antimicrobials.
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Affiliation(s)
- Emma R Holden
- Quadram Institute Biosciences, Norwich, United Kingdom
| | - Mark A Webber
- Quadram Institute Biosciences, Norwich, United Kingdom.,Norwich Medical School, University of East Anglia, Norwich, United Kingdom
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93
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Holden ER, Webber MA. MarA, RamA, and SoxS as Mediators of the Stress Response: Survival at a Cost. Front Microbiol 2020; 11:828. [PMID: 32431683 PMCID: PMC7216687 DOI: 10.3389/fmicb.2020.00828] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 04/07/2020] [Indexed: 01/17/2023] Open
Abstract
To survive and adapt to changing environments, bacteria have evolved mechanisms to express appropriate genes at appropriate times. Exposure to antimicrobials triggers a global stress response in Enterobacteriaceae, underpinned by activation of a family of transcriptional regulators, including MarA, RamA, and SoxS. These control a program of altered gene expression allowing a rapid and measured response to improve fitness in the presence of toxic drugs. Increased expression of marA, ramA, and soxS up regulates efflux activity to allow detoxification of the cell. However, this also results in trade-offs in other phenotypes, such as impaired growth rates, biofilm formation and virulence. Here, we review the current knowledge regarding the trade-offs that exist between drug survival and other phenotypes that result from induction of marA, ramA, and soxS. Additionally, we present some new findings linking expression of these regulators and biofilm formation in Enterobacteriaceae, thereby demonstrating the interconnected nature of regulatory networks within the cell and explaining how trade-offs can exist between important phenotypes. This has important implications for our understanding of how bacterial virulence and biofilms can be influenced by exposure to antimicrobials.
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Affiliation(s)
- Emma R Holden
- Quadram Institute Biosciences, Norwich, United Kingdom
| | - Mark A Webber
- Quadram Institute Biosciences, Norwich, United Kingdom.,Norwich Medical School, University of East Anglia, Norwich, United Kingdom
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94
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Adewunmi Y, Namjilsuren S, Walker WD, Amato DN, Amato DV, Mavrodi OV, Patton DL, Mavrodi DV. Antimicrobial Activity of, and Cellular Pathways Targeted by, p-Anisaldehyde and Epigallocatechin Gallate in the Opportunistic Human Pathogen Pseudomonas aeruginosa. Appl Environ Microbiol 2020; 86:e02482-19. [PMID: 31811038 PMCID: PMC6997733 DOI: 10.1128/aem.02482-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 12/04/2019] [Indexed: 12/13/2022] Open
Abstract
Plant-derived aldehydes are constituents of essential oils that possess broad-spectrum antimicrobial activity and kill microorganisms without promoting resistance. In our previous study, we incorporated p-anisaldehyde from star anise into a polymer network called proantimicrobial networks via degradable acetals (PANDAs) and used it as a novel drug delivery platform. PANDAs released p-anisaldehyde upon a change in pH and humidity and controlled the growth of the multidrug-resistant pathogen Pseudomonas aeruginosa PAO1. In this study, we identified the cellular pathways targeted by p-anisaldehyde by generating 10,000 transposon mutants of PAO1 and screened them for hypersensitivity to p-anisaldehyde. To improve the antimicrobial efficacy of p-anisaldehyde, we combined it with epigallocatechin gallate (EGCG), a polyphenol from green tea, and demonstrated that it acts synergistically with p-anisaldehyde in killing P. aeruginosa We then used transcriptome sequencing to profile the responses of P. aeruginosa to p-anisaldehyde, EGCG, and their combination. The exposure to p-anisaldehyde altered the expression of genes involved in modification of the cell envelope, membrane transport, drug efflux, energy metabolism, molybdenum cofactor biosynthesis, and the stress response. We also demonstrate that the addition of EGCG reversed many p-anisaldehyde-coping effects and induced oxidative stress. Our results provide insight into the antimicrobial activity of p-anisaldehyde and its interactions with EGCG and may aid in the rational identification of new synergistically acting combinations of plant metabolites. Our study also confirms the utility of the thiol-ene polymer platform for the sustained and effective delivery of hydrophobic and volatile antimicrobial compounds.IMPORTANCE Essential oils (EOs) are plant-derived products that have long been exploited for their antimicrobial activities in medicine, agriculture, and food preservation. EOs represent a promising alternative to conventional antibiotics due to their broad-range antimicrobial activity, low toxicity to human commensal bacteria, and capacity to kill microorganisms without promoting resistance. Despite the progress in the understanding of the biological activity of EOs, our understanding of many aspects of their mode of action remains inconclusive. The overarching aim of this work was to address these gaps by studying the molecular interactions between an antimicrobial plant aldehyde and the opportunistic human pathogen Pseudomonas aeruginosa The results of this study identify the microbial genes and associated pathways involved in the response to antimicrobial phytoaldehydes and provide insights into the molecular mechanisms governing the synergistic effects of individual constituents within essential oils.
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Affiliation(s)
- Yetunde Adewunmi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Sanchirmaa Namjilsuren
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - William D Walker
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Dahlia N Amato
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Douglas V Amato
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Olga V Mavrodi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
- South MS Branch Experiment Station, Mississippi State University, Poplarville, Mississippi, USA
| | - Derek L Patton
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Dmitri V Mavrodi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
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95
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Sidrim JJ, Amando BR, Gomes FI, do Amaral MS, de Sousa PC, Ocadaque CJ, Brilhante RS, A Cordeiro RD, Rocha MF, Scm Castelo-Branco DD. Chlorpromazine-impregnated catheters as a potential strategy to control biofilm-associated urinary tract infections. Future Microbiol 2020; 14:1023-1034. [PMID: 31469013 DOI: 10.2217/fmb-2019-0092] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Aim: This study proposes the impregnation of Foley catheters with chlorpromazine (CPZ) to control biofilm formation by Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae. Materials & methods: The minimum inhibitory concentrations (MICs) for CPZ and the effect of CPZ on biofilm formation were assessed. Afterward, biofilm formation and the effect of ciprofloxacin and meropenem (at MIC) on mature biofilms grown on CPZ-impregnated catheters were evaluated. Results: CPZ MIC range was 39.06-625 mg/l. CPZ significantly reduced (p < 0.05) biofilm formation in vitro and on impregnated catheters. In addition, CPZ-impregnation potentiated the antibiofilm activity of ciprofloxacin and meropenem. Conclusion: These findings bring perspectives for the use of CPZ as an adjuvant for preventing and treating catheter-associated urinary tract infections.
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Affiliation(s)
- José Jc Sidrim
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Specialized Medical Mycology Center, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Bruno R Amando
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Group of Applied Medical Microbiology, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Francisco If Gomes
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Group of Applied Medical Microbiology, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Marilia Smg do Amaral
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Group of Applied Medical Microbiology, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Paulo Cp de Sousa
- Walter Cantídio University Hospital, Rua Capitão Francisco Pedro, 1290 - Rodolfo Teófilo, Fortaleza, CE 60430-372, Brazil
| | - Crister J Ocadaque
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Group of Applied Medical Microbiology, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Raimunda Sn Brilhante
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Specialized Medical Mycology Center, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Rossana de A Cordeiro
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Specialized Medical Mycology Center, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
| | - Marcos Fg Rocha
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Specialized Medical Mycology Center, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil.,College of Veterinary, State University of Ceará. Av. Dr. Silas Munguba, 1700, Campus do Itaperi - CEP 60714-903, Fortaleza, Ceará, Brazil
| | - Débora de Scm Castelo-Branco
- Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Specialized Medical Mycology Center, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil.,Department of Pathology & Legal Medicine, Postgraduate Program in Medical Microbiology, Group of Applied Medical Microbiology, Federal University of Ceará, Rua Cel, Nunes de Melo, 1315 - Rodolfo Teófilo - CEP 60430-275, Fortaleza, Ceará, Brazil
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96
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Pulbutr P, Thongrak K, Thitprapai A, Rattanakiat S, Mudjupa C, Jaruchotikamol A. Inhibitory activity of lupinifolin isolated from Derris reticulata stem against biofilm formation of Streptococcus mutans and Staphylococcus aureus. Pharmacognosy Res 2020. [DOI: 10.4103/pr.pr_57_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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97
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McNeil HE, Alav I, Torres RC, Rossiter AE, Laycock E, Legood S, Kaur I, Davies M, Wand M, Webber MA, Bavro VN, Blair JMA. Identification of binding residues between periplasmic adapter protein (PAP) and RND efflux pumps explains PAP-pump promiscuity and roles in antimicrobial resistance. PLoS Pathog 2019; 15:e1008101. [PMID: 31877175 PMCID: PMC6975555 DOI: 10.1371/journal.ppat.1008101] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/22/2020] [Accepted: 09/20/2019] [Indexed: 11/19/2022] Open
Abstract
Active efflux due to tripartite RND efflux pumps is an important mechanism of clinically relevant antibiotic resistance in Gram-negative bacteria. These pumps are also essential for Gram-negative pathogens to cause infection and form biofilms. They consist of an inner membrane RND transporter; a periplasmic adaptor protein (PAP), and an outer membrane channel. The role of PAPs in assembly, and the identities of specific residues involved in PAP-RND binding, remain poorly understood. Using recent high-resolution structures, four 3D sites involved in PAP-RND binding within each PAP protomer were defined that correspond to nine discrete linear binding sequences or "binding boxes" within the PAP sequence. In the important human pathogen Salmonella enterica, these binding boxes are conserved within phylogenetically-related PAPs, such as AcrA and AcrE, while differing considerably between divergent PAPs such as MdsA and MdtA, despite overall conservation of the PAP structure. By analysing these binding sequences we created a predictive model of PAP-RND interaction, which suggested the determinants that may allow promiscuity between certain PAPs, but discrimination of others. We corroborated these predictions using direct phenotypic data, confirming that only AcrA and AcrE, but not MdtA or MsdA, can function with the major RND pump AcrB. Furthermore, we provide functional validation of the involvement of the binding boxes by disruptive site-directed mutagenesis. These results directly link sequence conservation within identified PAP binding sites with functional data providing mechanistic explanation for assembly of clinically relevant RND-pumps and explain how Salmonella and other pathogens maintain a degree of redundancy in efflux mediated resistance. Overall, our study provides a novel understanding of the molecular determinants driving the RND-PAP recognition by bridging the available structural information with experimental functional validation thus providing the scientific community with a predictive model of pump-contacts that could be exploited in the future for the development of targeted therapeutics and efflux pump inhibitors.
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Affiliation(s)
- Helen E. McNeil
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Ilyas Alav
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | | | - Amanda E. Rossiter
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Eve Laycock
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Simon Legood
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Inderpreet Kaur
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Matthew Davies
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Matthew Wand
- Public Health England, National Infection Service, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Mark A. Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom
| | - Vassiliy N. Bavro
- School of Life Sciences, University of Essex, Colchester, United Kingdom
- * E-mail: (VNB); (JMAB)
| | - Jessica M. A. Blair
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail: (VNB); (JMAB)
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98
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Wang J, Jiao H, Meng J, Qiao M, Du H, He M, Ming K, Liu J, Wang D, Wu Y. Baicalin Inhibits Biofilm Formation and the Quorum-Sensing System by Regulating the MsrA Drug Efflux Pump in Staphylococcus saprophyticus. Front Microbiol 2019; 10:2800. [PMID: 31921008 PMCID: PMC6915091 DOI: 10.3389/fmicb.2019.02800] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/18/2019] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus saprophyticus (S. saprophyticus) is one of the main pathogens that cause serious infection due to its acquisition of antibiotic resistance. The efflux pump decreases antibiotic abundance, and biofilm compromises the penetration of antibiotics. It has been reported that baicalin is a potential agent to inhibit efflux pumps, biofilm formation, and quorum-sensing systems. The purpose of this study was to investigate whether baicalin can inhibit S. saprophyticus biofilm formation and the quorum-sensing system by inhibiting the MsrA efflux pump. First, the mechanism of baicalin inhibiting efflux was investigated by the ethidium bromide (EtBr) efflux assay, measurement of ATP content, and pyruvate kinase (PK) activities. These results revealed that baicalin significantly reduced the efflux of EtBr, the ATP content, and the activity of PK. Moreover, its role in biofilm formation and the agr system was studied by crystal violet staining, confocal laser scanning microscopy, scanning electron microscopy, and real-time polymerase chain reaction. These results showed that baicalin decreased biofilm formation, inhibited bacterial aggregation, and downregulated mRNA transcription levels of the quorum-sensing system regulators agrA, agrC, RNAIII, and sarA. Correlation analysis indicated that there was a strong positive correlation between the efflux pump and biofilm formation and the agr system. We demonstrate for the first time that baicalin inhibits biofilm formation and the agr quorum-sensing system by inhibiting the efflux pump in S. saprophyticus. Therefore, baicalin is a potential therapeutic agent for S. saprophyticus biofilm-associated infections.
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Affiliation(s)
- Jinli Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Haihong Jiao
- Key Laboratory of Tarim Animal Husbandry Science and Technology of Xinjiang Production & Construction Corps, College of Animal Science, Tarim University, Alar, China
| | - Jinwu Meng
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Mingyu Qiao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Hongxu Du
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Miao He
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Ke Ming
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jiaguo Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Deyun Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yi Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
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99
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Zimmermann S, Klinger-Strobel M, Bohnert JA, Wendler S, Rödel J, Pletz MW, Löffler B, Tuchscherr L. Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation. Front Microbiol 2019; 10:2762. [PMID: 31849901 PMCID: PMC6901667 DOI: 10.3389/fmicb.2019.02762] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/12/2019] [Indexed: 11/26/2022] Open
Abstract
Staphylococcus aureus has acquired resistance to antibiotics since their first use. The S. aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. Different compounds have been identified as potential efflux pump inhibitors (EPIs) of NorA that result in increased intracellular concentration of antibiotics, restoring their antibacterial activity and cell susceptibility. However, none of the currently known EPIs have been approved for clinical use, probably due to their toxicity profiles. In the present study, we screened approved drugs for possible efflux pump inhibition. By screening a compound library of approximately 1200 different drugs, we identified nilotinib, a tyrosine kinase inhibitor, as showing the best efflux pump inhibitory activity, with a fractional inhibitory concentration index of 0.1875, indicating synergism with ciprofloxacin, and a minimum effective concentration as low as 0.195 μM. Moreover, at 0.39 μM, nilotinib, in combination with 8 μg/mL of ciprofloxacin, led to a significant reduction in biofilm formation and preformed mature biofilms. This is the first description of an approved drug that can be used as an efflux pump inhibitor and to reduce biofilms formation at clinically achievable concentrations.
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Affiliation(s)
- Saskia Zimmermann
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Mareike Klinger-Strobel
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
| | - Jürgen A Bohnert
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany.,Institute of Medical Microbiology, Greifswald University Hospital, Greifswald, Germany
| | - Sindy Wendler
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany
| | - Jürgen Rödel
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany
| | - Mathias W Pletz
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Lorena Tuchscherr
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
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100
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Reza A, Sutton JM, Rahman KM. Effectiveness of Efflux Pump Inhibitors as Biofilm Disruptors and Resistance Breakers in Gram-Negative (ESKAPEE) Bacteria. Antibiotics (Basel) 2019; 8:antibiotics8040229. [PMID: 31752382 PMCID: PMC6963839 DOI: 10.3390/antibiotics8040229] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022] Open
Abstract
Antibiotic resistance represents a significant threat to the modern healthcare provision. The ESKAPEE pathogens (Enterococcus faecium., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli), in particular, have proven to be especially challenging to treat, due to their intrinsic and acquired ability to rapidly develop resistance mechanisms in response to environmental threats. The development of biofilm has been characterised as an essential contributing factor towards antimicrobial-resistance and tolerance. Several studies have implicated the involvement of efflux pumps in antibiotic resistance, both directly, via drug extrusion and indirectly, through the formation of biofilm. As a result, the underlying mechanism of these pumps has attracted considerable interest due to the potential of targeting these protein structures and developing novel adjunct therapies. Subsequent investigations have revealed the ability of efflux pump-inhibitors (EPIs) to block drug-extrusion and disrupt biofilm formation, thereby, potentiating antibiotics and reversing resistance of pathogen towards them. This review will discuss the potential of EPIs as a possible solution to antimicrobial resistance, examining different challenges to the design of these compounds, with an emphasis on Gram-negative ESKAPEE pathogens.
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Affiliation(s)
- Akif Reza
- Institute of Pharmaceutical Science, King’s College London, London, SE1 9NH, UK;
| | - J. Mark Sutton
- National Infections Service, Public Health England, Porton Down, Salisbury, Wiltshire SP4 0JG, UK;
| | - Khondaker Miraz Rahman
- Institute of Pharmaceutical Science, King’s College London, London, SE1 9NH, UK;
- Correspondence: ; Tel.: +44-(0)207-848-1891
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