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Kim U, Oh SW. Antimicrobial resistance induction potential of grapefruit seed extract on multi-species biofilm of E. coli in food industry. Int J Food Microbiol 2024; 424:110849. [PMID: 39098160 DOI: 10.1016/j.ijfoodmicro.2024.110849] [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: 03/27/2024] [Revised: 07/09/2024] [Accepted: 07/29/2024] [Indexed: 08/06/2024]
Abstract
Biofilm formation in natural environments involving complex multi-structural arrangements hinders challenges in antimicrobial resistance. This study investigated the antimicrobial resistance potential of grapefruit seed extract (GSE) by examining the formation of mono-, dual-, and multi-species biofilms. We also explored the counterintuitive effect in response to GSE at various concentrations, including minimum inhibitory concentration (MIC) and sub-MIC (1/2 and 1/4 MIC). The results of the swimming and swarming motility tests revealed increased motility at the sub-MIC of GSE. The crystal violet assay demonstrated increased biofilm formation in multi-species biofilms, highlighting the synergistic effect of Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes. At the MIC concentration of GSE, field emission scanning electron microscopy (FE-SEM) revealed cell morphology damage, while sub-MIC increased biofilm formation and architectural complexity. Multi-species biofilms demonstrated greater biofilm-forming ability and antimicrobial resistance than mono-species biofilms, indicating synergistic interactions and enhanced resilience. These findings highlight the importance of understanding biofilm dynamics and antimicrobial resistance to ensure environmental safety.
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Affiliation(s)
- Unji Kim
- Department of Food and Nutrition, Kookmin University, Seoul, Republic of Korea
| | - Se-Wook Oh
- Department of Food and Nutrition, Kookmin University, Seoul, Republic of Korea.
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2
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Ma Y, Tang WS, Liu SY, Khoo BL, Chua SL. Juglone as a Natural Quorum Sensing Inhibitor against Pseudomonas aeruginosa pqs-Mediated Virulence and Biofilms. ACS Pharmacol Transl Sci 2024; 7:533-543. [PMID: 38357290 PMCID: PMC10863437 DOI: 10.1021/acsptsci.3c00354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/30/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024]
Abstract
Pseudomonas aeruginosa is a notorious opportunistic pathogen associated with chronic biofilm-related infections, posing a significant challenge to effective treatment strategies. Quorum sensing (QS) and biofilm formation are critical virulence factors employed by P. aeruginosa, contributing to its pathogenicity and antibiotic resistance. Other than the homoserine-based QS systems, P. aeruginosa also possesses the quinolone-based Pseudomonas quinolone signal (PQS) QS signaling. Synthesis of the PQS signaling molecule is achieved by the pqsABCDEH operon, whereas the PQS signaling response was mediated by the PqsR receptor. In this study, we report the discovery of a novel natural compound, Juglone, with potent inhibitory effects on pqs QS and biofilm formation in P. aeruginosa. Through an extensive screening of natural compounds from diverse sources, we identified Juglone, a natural compound from walnut, as a promising candidate. We showed that Juglone could inhibit PqsR and the molecular docking results revealed that Juglone could potentially bind to the PqsR active site. Furthermore, Juglone could inhibit pqs-regulated virulence factors, such as pyocyanin and the PQS QS signaling molecule. Juglone could also significantly reduce both the quantity and quality of P. aeruginosa biofilms. Notably, this compound exhibited minimal cytotoxicity toward mammalian cells, suggesting its potential safety for therapeutic applications. To explore the clinical relevance of Juglone, we investigated its combinatorial effects with colistin, a commonly used antibiotic against P. aeruginosa infections. The Juglone-colistin combinatorial treatment could eliminate biofilms formed by wild-type P. aeruginosa PAO1 and its clinical isolates collected from cystic fibrosis patients. The Juglone-colistin combinatorial therapy dramatically improved colistin efficacy and reduced inflammation in a wound infection model, indicating its potential for clinical utility. In conclusion, the discovery of Juglone provides insights into the development of innovative antivirulence therapeutic strategies to combat P. aeruginosa biofilm-associated infections.
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Affiliation(s)
- Yeping Ma
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Wing Suet Tang
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Sylvia Yang Liu
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Bee Luan Khoo
- Department
of Biomedical Engineering, City University
of Hong Kong, Kowloon, Hong Kong SAR 999077, China
- Hong
Kong Center for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong SAR 999077, China
- City
University of Hong Kong–Shenzhen Futian Research Institute, Shenzhen 518172, China
| | - Song Lin Chua
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
- State
Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
- Research
Centre of Deep Space Explorations (RCDSE), The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
- Research
Institute for Future Food (RiFood), The
Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
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3
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Yousefi Nojookambari N, Eslami G, Sadredinamin M, Vaezjalali M, Nikmanesh B, Dehbanipour R, Yazdansetad S, Ghalavand Z. Sub-minimum inhibitory concentrations (sub-MICs) of colistin on Acinetobacter baumannii biofilm formation potency, adherence, and invasion to epithelial host cells: an experimental study in an Iranian children's referral hospital. Microbiol Spectr 2024; 12:e0252323. [PMID: 38230925 PMCID: PMC10846280 DOI: 10.1128/spectrum.02523-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 11/07/2023] [Indexed: 01/18/2024] Open
Abstract
Here, we described the efficacy of colistin sub-minimum inhibitory concentrations (sub-MICs) on biofilm-forming activity, host epithelial cell adherence, and invasion capacity of Acinetobacter baumannii strains collected from children admitted to the Children's Medical Center Hospital. Biofilm formation potency of A. baumannii clinical isolates was measured using a 96-well microtiter plate assay. Distribution of biofilm-related genes, including bap, abaI, ompA, csuE, and blaPER-1, was detected by PCR. The mRNA expression level of ompA and csuE was measured by qPCR in the presence of ¼ and ½ MICs of colistin. A. baumannii adhesion and invasion to eukaryotic host cells were phenotypically assayed at sub-MICs of colistin. Eighty percent (56/70) and 35.7% (25/70) of A. baumannii isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR) phenotypes, respectively. The strong, moderate, and weak biofilm producers of A. baumannii were 37.1% (26/70), 32.8%, (23/70), and 22.8% (16/70), respectively. The frequencies of biofilm-associated genes were 100% for abaI, ompA, and csuE, followed by 22.8% (16/70) and 24.3% (17/70) for bap and blaPER-1, respectively. The downregulation of csuE and ompA expression levels was observed in the sub-MIC of colistin. In vitro cell culture study showed a decreased capability of A. baumannii to adhere to the human epithelial cells at sub-inhibitory doses of colistin; however, none of the isolates could invade HEp-2 cells. Our study showed that the genes encoding biofilm-associated proteins undergo downregulation in expression levels after exposure to sub-MICs of colistin in A. baumannii. Longitudinal in vivo studies are needed to fully understand the clinical aspects of pathogenicity mechanisms and evolutionary dynamics of drug resistance.IMPORTANCESince the toxicity of colistin is dose dependent, there is a focus on strategies that reduce the dose while maintaining the therapeutic effect of the drug. Our findings about sub-inhibitory doses of colistin provide a novel insight into the logical use of colistin to treat and control Acinetobacter baumannii-related infections in clinical practice.
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Affiliation(s)
- Neda Yousefi Nojookambari
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gita Eslami
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehrzad Sadredinamin
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Vaezjalali
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bahram Nikmanesh
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran
| | - Razieh Dehbanipour
- Department of Microbiology, School of Medicine, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Sajjad Yazdansetad
- Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Zohreh Ghalavand
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Ding Y, Hao J, Xiao W, Ye C, Xiao X, Jian C, Tang M, Li G, Liu J, Zeng Z. Role of efflux pumps, their inhibitors, and regulators in colistin resistance. Front Microbiol 2023; 14:1207441. [PMID: 37601369 PMCID: PMC10436536 DOI: 10.3389/fmicb.2023.1207441] [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: 04/17/2023] [Accepted: 07/13/2023] [Indexed: 08/22/2023] Open
Abstract
Colistin is highly promising against multidrug-resistant and extensively drug-resistant bacteria clinically. Bacteria are resistant to colistin mainly through mcr and chromosome-mediated lipopolysaccharide (LPS) synthesis-related locus variation. However, the current understanding cannot fully explain the resistance mechanism in mcr-negative colistin-resistant strains. Significantly, the contribution of efflux pumps to colistin resistance remains to be clarified. This review aims to discuss the contribution of efflux pumps and their related transcriptional regulators to colistin resistance in various bacteria and the reversal effect of efflux pump inhibitors on colistin resistance. Previous studies suggested a complex regulatory relationship between the efflux pumps and their transcriptional regulators and LPS synthesis, transport, and modification. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP), 1-(1-naphthylmethyl)-piperazine (NMP), and Phe-Arg-β-naphthylamide (PAβN) all achieved the reversal of colistin resistance, highlighting the role of efflux pumps in colistin resistance and their potential for adjuvant development. The contribution of the efflux pumps to colistin resistance might also be related to specific genetic backgrounds. They can participate in colistin tolerance and heterogeneous resistance to affect the treatment efficacy of colistin. These findings help understand the development of resistance in mcr-negative colistin-resistant strains.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jinbo Liu
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Zhangrui Zeng
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
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Deshamukhya C, Das BJ, Paul D, Dhar Chanda D, Bhattacharjee A. Imipenem and meropenem influence the Las/Rhl quorum-sensing systems in clinical isolates of Pseudomonas aeruginosa. Lett Appl Microbiol 2023; 76:ovad084. [PMID: 37496211 DOI: 10.1093/lambio/ovad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/12/2023] [Accepted: 07/25/2023] [Indexed: 07/28/2023]
Abstract
The present study was conducted to study the influence of imipenem and meropenem at subinhibitory concentration on the transcriptional response of Las/Rhl quorum-sensing systems in isolates of Pseudomonas aeruginosa. In the present study, six representative carbapenem nonsusceptible clinical isolates of P. aeruginosa were obtained. The agar dilution method was used to determine the minimum inhibitory concentration against imipenem and meropenem. The bacterial isolates were then cultured up to the early log phase in fresh Luria Bertani (LB) broths at 37°C with and without 2 µg mL-1 imipenem and meropenem, respectively. mRNA was then isolated from the bacterial isolates and was immediately reverse-transcribed to cDNA. The relative quantity of the expression of the lasI, lasR, rhlI, and rhlR genes was assessed by quantitative real-time Polymerase Chain Reaction (PCR) using the ΔΔCt method. The transcriptional response of the lasI and lasR genes was upregulated at subinhibitory concentration of meropenem. In contrast, the transcriptional response of the lasI, lasR, and rhlR genes was downregulated at subinhibitory concentration of imipenem as compared to the expression in untreated isolates. The data obtained in the current study showcased the ability of imipenem and meropenem to influence the response of the quorum-sensing genes at subinhibitory concentration.
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Affiliation(s)
| | - Bhaskar J Das
- Department of Microbiology, Assam University, Silchar 788011, India
| | - Deepjyoti Paul
- Department of Microbiology, Assam University, Silchar 788011, India
| | - Debadatta Dhar Chanda
- Department of Microbiology, Silchar Medical College and Hospital, Silchar 788014, India
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6
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The two faces of pyocyanin - why and how to steer its production? World J Microbiol Biotechnol 2023; 39:103. [PMID: 36864230 PMCID: PMC9981528 DOI: 10.1007/s11274-023-03548-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 02/13/2023] [Indexed: 03/04/2023]
Abstract
The ambiguous nature of pyocyanin was noted quite early after its discovery. This substance is a recognized Pseudomonas aeruginosa virulence factor that causes problems in cystic fibrosis, wound healing, and microbiologically induced corrosion. However, it can also be a potent chemical with potential use in a wide variety of technologies and applications, e.g. green energy production in microbial fuel cells, biocontrol in agriculture, therapy in medicine, or environmental protection. In this mini-review, we shortly describe the properties of pyocyanin, its role in the physiology of Pseudomonas and show the ever-growing interest in it. We also summarize the possible ways of modulating pyocyanin production. We underline different approaches of the researchers that aim either at lowering or increasing pyocyanin production by using different culturing methods, chemical additives, physical factors (e.g. electromagnetic field), or genetic engineering techniques. The review aims to present the ambiguous character of pyocyanin, underline its potential, and signalize the possible further research directions.
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Amly DA, Hajardhini P, Jonarta AL, Yulianto HDK, Susilowati H. Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa. F1000Res 2021; 10:14. [PMID: 34540201 PMCID: PMC8424461 DOI: 10.12688/f1000research.27915.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/30/2021] [Indexed: 11/23/2022] Open
Abstract
Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of
P. aeruginosa. Methods:Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC
10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of
P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in
P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.
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Affiliation(s)
- Dina Auliya Amly
- Master of Dental Sciences Program, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Puspita Hajardhini
- Master of Dental Sciences Program, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Alma Linggar Jonarta
- Department of Oral Biology, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Heribertus Dedy Kusuma Yulianto
- Department of Dental Biomedical Sciences, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Heni Susilowati
- Department of Oral Biology, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
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8
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Nolan C, Behrends V. Sub-Inhibitory Antibiotic Exposure and Virulence in Pseudomonas aeruginosa. Antibiotics (Basel) 2021; 10:antibiotics10111393. [PMID: 34827331 PMCID: PMC8615142 DOI: 10.3390/antibiotics10111393] [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] [Received: 10/22/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is a prime opportunistic pathogen, one of the most important causes of hospital-acquired infections and the major cause of morbidity and mortality in cystic fibrosis lung infections. One reason for the bacterium's pathogenic success is the large array of virulence factors that it can employ. Another is its high degree of intrinsic and acquired resistance to antibiotics. In this review, we first summarise the current knowledge about the regulation of virulence factor expression and production. We then look at the impact of sub-MIC antibiotic exposure and find that the virulence-antibiotic interaction for P. aeruginosa is antibiotic-specific, multifaceted, and complex. Most studies undertaken to date have been in vitro assays in batch culture systems, involving short-term (<24 h) antibiotic exposure. Therefore, we discuss the importance of long-term, in vivo-mimicking models for future work, particularly highlighting the need to account for bacterial physiology, which by extension governs both virulence factor expression and antibiotic tolerance/resistance.
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9
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Hagras SAA, Hosny AEDMS, Helmy OM, Salem-Bekhit MM, Shakeel F, Farrag HA. Effect of sub-inhibitory concentrations of cefepime on biofilm formation by Pseudomonas aeruginosa. Can J Microbiol 2021; 67:894-901. [PMID: 34731576 DOI: 10.1139/cjm-2021-0229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½-1/256 MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and ¼ MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.
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Affiliation(s)
- Soheir A A Hagras
- Department of Drug Radiation Research, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority, Cairo, Egypt.,Inaya Medical Colleges, Riyadh, Saudi Arabia
| | - Alaa El-Dien M S Hosny
- Department of Microbiology & Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Omneya M Helmy
- Department of Microbiology & Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Mounir M Salem-Bekhit
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.,Department of Microbiology & Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Faiyaz Shakeel
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Hala A Farrag
- Department of Drug Radiation Research, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority, Cairo, Egypt
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Cianciulli Sesso A, Lilić B, Amman F, Wolfinger MT, Sonnleitner E, Bläsi U. Gene Expression Profiling of Pseudomonas aeruginosa Upon Exposure to Colistin and Tobramycin. Front Microbiol 2021; 12:626715. [PMID: 33995291 PMCID: PMC8120321 DOI: 10.3389/fmicb.2021.626715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/31/2021] [Indexed: 11/22/2022] Open
Abstract
Pseudomonas aeruginosa (Pae) is notorious for its high-level resistance toward clinically used antibiotics. In fact, Pae has rendered most antimicrobials ineffective, leaving polymyxins and aminoglycosides as last resort antibiotics. Although several resistance mechanisms of Pae are known toward these drugs, a profounder knowledge of hitherto unidentified factors and pathways appears crucial to develop novel strategies to increase their efficacy. Here, we have performed for the first time transcriptome analyses and ribosome profiling in parallel with strain PA14 grown in synthetic cystic fibrosis medium upon exposure to polymyxin E (colistin) and tobramycin. This approach did not only confirm known mechanisms involved in colistin and tobramycin susceptibility but revealed also as yet unknown functions/pathways. Colistin treatment resulted primarily in an anti-oxidative stress response and in the de-regulation of the MexT and AlgU regulons, whereas exposure to tobramycin led predominantly to a rewiring of the expression of multiple amino acid catabolic genes, lower tricarboxylic acid (TCA) cycle genes, type II and VI secretion system genes and genes involved in bacterial motility and attachment, which could potentially lead to a decrease in drug uptake. Moreover, we report that the adverse effects of tobramycin on translation are countered with enhanced expression of genes involved in stalled ribosome rescue, tRNA methylation and type II toxin-antitoxin (TA) systems.
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Affiliation(s)
- Anastasia Cianciulli Sesso
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Branislav Lilić
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Fabian Amman
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Michael T Wolfinger
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria.,Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Elisabeth Sonnleitner
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Udo Bläsi
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
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11
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Molina Mora JA, Montero-Manso P, García-Batán R, Campos-Sánchez R, Vilar-Fernández J, García F. A first perturbome of Pseudomonas aeruginosa: Identification of core genes related to multiple perturbations by a machine learning approach. Biosystems 2021; 205:104411. [PMID: 33757842 DOI: 10.1016/j.biosystems.2021.104411] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 01/27/2023]
Abstract
Tolerance to stress conditions is vital for organismal survival, including bacteria under specific environmental conditions, antibiotics, and other perturbations. Some studies have described common modulation and shared genes during stress response to different types of disturbances (termed as perturbome), leading to the idea of central control at the molecular level. We implemented a robust machine learning approach to identify and describe genes associated with multiple perturbations or perturbome in a Pseudomonas aeruginosa PAO1 model. Using microarray datasets from the Gene Expression Omnibus (GEO), we evaluated six approaches to rank and select genes: using two methodologies, data single partition (SP method) or multiple partitions (MP method) for training and testing datasets, we evaluated three classification algorithms (SVM Support Vector Machine, KNN K-Nearest neighbor and RF Random Forest). Gene expression patterns and topological features at the systems level were included to describe the perturbome elements. We were able to select and describe 46 core response genes associated with multiple perturbations in P. aeruginosa PAO1 and it can be considered a first report of the P. aeruginosa perturbome. Molecular annotations, patterns in expression levels, and topological features in molecular networks revealed biological functions of biosynthesis, binding, and metabolism, many of them related to DNA damage repair and aerobic respiration in the context of tolerance to stress. We also discuss different issues related to implemented and assessed algorithms, including data partitioning, classification approaches, and metrics. Altogether, this work offers a different and robust framework to select genes using a machine learning approach.
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Affiliation(s)
- Jose Arturo Molina Mora
- Centro de Investigacion en Enfermedades Tropicales (CIET) and Facultad de Microbiología, Universidad de Costa Rica, San Jose, Costa Rica.
| | | | - Raquel García-Batán
- Centro de Investigacion en Enfermedades Tropicales (CIET) and Facultad de Microbiología, Universidad de Costa Rica, San Jose, Costa Rica.
| | - Rebeca Campos-Sánchez
- Centro de Investigación en Biología Celular y Molecular (CIBCM), Universidad de Costa Rica, San José, Costa Rica.
| | | | - Fernando García
- Centro de Investigacion en Enfermedades Tropicales (CIET) and Facultad de Microbiología, Universidad de Costa Rica, San Jose, Costa Rica.
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12
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Shang D, Han X, Du W, Kou Z, Jiang F. Trp-Containing Antibacterial Peptides Impair Quorum Sensing and Biofilm Development in Multidrug-Resistant Pseudomonas aeruginosa and Exhibit Synergistic Effects With Antibiotics. Front Microbiol 2021; 12:611009. [PMID: 33643239 PMCID: PMC7906020 DOI: 10.3389/fmicb.2021.611009] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/20/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa uses quorum sensing (QS) to control virulence, biofilm formation and antibiotic efflux pump expression. The development of effective small molecules targeting the QS system and biofilm formation represents a novel attractive strategy. In this present study, the effects of a series of Trp-containing peptides on the QS-regulated virulence and biofilm development of multidrug-resistant P. aeruginosa, as well as their synergistic antibacterial activity with three classes of traditional chemical antibiotics were investigated. The results showed that Trp-containing peptides at low concentrations reduced the production of QS-regulated virulence factors by downregulating the gene expression of both the las and rhl systems in the strain MRPA0108. Biofilm formation was inhibited in a concentration-dependent manner, which was associated with extracellular polysaccharide production inhibition by downregulating pelA, algD, and pslA transcription. These changes correlated with alterations in the extracellular production of pseudomonal virulence factors and swarming motility. In addition, the combination of Trp-containing peptides at low concentration with the antibiotics ceftazidime and piperacillin provided synergistic effects. Notably, L11W and L12W showed the highest synergy with ceftazidime and piperacillin. A mechanistic study demonstrated that the Trp-containing peptides, especially L12W, significantly decreased β-lactamase activity and expression of efflux pump genes OprM, MexX, and MexA, resulting in a reduction in antibiotic efflux from MRPA0108 cells and thus increasing the antibacterial activity of these antibiotics against MRPA0108.
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Affiliation(s)
- Dejing Shang
- School of Life Sciences, Liaoning Normal University, Dalian, China
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian, China
| | - Xue Han
- School of Life Sciences, Liaoning Normal University, Dalian, China
| | - Wanying Du
- School of Life Sciences, Liaoning Normal University, Dalian, China
| | - Zhiru Kou
- School of Life Sciences, Liaoning Normal University, Dalian, China
| | - Fengquan Jiang
- Clinical Laboratory Department of the First Affiliated Hospital, Dalian Medical University, Dalian, China
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13
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Amly DA, Hajardhini P, Jonarta AL, Yulianto HDK, Susilowati H. Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa. F1000Res 2021; 10:14. [PMID: 34540201 PMCID: PMC8424461 DOI: 10.12688/f1000research.27915.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/30/2021] [Indexed: 11/17/2023] Open
Abstract
Background:Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods:Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.
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Affiliation(s)
- Dina Auliya Amly
- Master of Dental Sciences Program, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Puspita Hajardhini
- Master of Dental Sciences Program, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Alma Linggar Jonarta
- Department of Oral Biology, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Heribertus Dedy Kusuma Yulianto
- Department of Dental Biomedical Sciences, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
| | - Heni Susilowati
- Department of Oral Biology, Faculty of Dentistry, Universitas Gadjah Mada, Sleman, Yogyakarta, 55281, Indonesia
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Serna N, Carratalá JV, Parladé E, Sánchez-Chardi A, Aviñó A, Unzueta U, Mangues R, Eritja R, Ferrer-Miralles N, Vazquez E, Villaverde A. Developing Protein-Antitumoral Drug Nanoconjugates as Bifunctional Antimicrobial Agents. ACS APPLIED MATERIALS & INTERFACES 2020; 12:57746-57756. [PMID: 33325705 DOI: 10.1021/acsami.0c18317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A novel concept about bifunctional antimicrobial drugs, based on self-assembling protein nanoparticles, has been evaluated here over two biofilm-forming pathogens, namely Pseudomonas aeruginosa and Staphylococcus aureus. Two structurally different antimicrobial peptides (GWH1 and PaDBS1R1) were engineered to form regular nanoparticles of around 35 nm, to which the small molecular weight drug Floxuridine was covalently conjugated. Both the assembled peptides and the chemical, a conventional cytotoxic drug used in oncotherapy, showed potent antimicrobial activities that were enhanced by the combination of both molecules in single pharmacological entities. Therefore, the resulting prototypes show promises as innovative nanomedicines, being potential alternatives to conventional antibiotics. The biological performance and easy fabrication of these materials fully support the design of protein-based hybrid constructs for combined molecular therapies, expected to have broad applicability beyond antimicrobial medicines. In addition, the approach taken here validates the functional exploration and repurposing of antitumoral drugs, which at low concentrations perform well as unexpected biofilm-inhibiting agents.
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Affiliation(s)
- Naroa Serna
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Jose Vicente Carratalá
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Eloi Parladé
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Alejandro Sánchez-Chardi
- Servei de Microscòpia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain
| | - Anna Aviñó
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, 08034 Barcelona, Spain
| | - Ugutz Unzueta
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
- Biomedical Research Institute Sant Pau (IIB Sant Pau), Sant Antoni Maria Claret 167, 08025 Barcelona, Spain
| | - Ramón Mangues
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
- Biomedical Research Institute Sant Pau (IIB Sant Pau), Sant Antoni Maria Claret 167, 08025 Barcelona, Spain
| | - Ramón Eritja
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, 08034 Barcelona, Spain
| | - Neus Ferrer-Miralles
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Esther Vazquez
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Antonio Villaverde
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, 28029 Madrid, Spain
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Immunomodulatory effects of colistin on host responses against carbapenem-resistant Klebsiella pneumoniae biofilms. Int J Antimicrob Agents 2020; 56:106182. [PMID: 33045355 DOI: 10.1016/j.ijantimicag.2020.106182] [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: 12/27/2019] [Revised: 07/04/2020] [Accepted: 10/03/2020] [Indexed: 12/17/2022]
Abstract
Colistin (CST) is a last-resort therapeutic option for carbapenem-resistant Klebsiella pneumoniae (CR-Kp) infections in critically ill patients. The effect of subinhibitory CST concentrations (sub-MICs) on biofilm formation is organism-dependent. We investigated the interactions between CST and innate immune cells against CR-Kp biofilms (CR-KpBF) by studying the effect of biofilm sub-MICs of CST on (i) damage induced by human polymorphonuclear neutrophils (PMNs) on CR-KpBF and (ii) the immunomodulatory potential on human mononuclear cells (MNCs) exposed to CR-KpBF. The impact of CST on PMN-induced biofilm damage was assessed by XTT reduction assay. Signal transduction and gene expression profiles in response to CST sub-MICs of MNCs exposed to CR-KpBF were studied by RT-PCR and multiplex ELISA. Pre-exposure of CR-Kp to 0.06 mg/L CST led to subsequent increased PMN-mediated biofilm damage against CR-KpBF in the presence of CST biofilm sub-MICs: there was an additive effect at 2, 4, 8 and 16 mg/L. However, the overall biofilm damage was not >52%. MNCs responded to CR-KpBF through Toll-like receptor 2 (TLR2) by 2.5-fold upregulation and NLRP3 inflammasome activation. CR-KpBF stimulated increased production of interleukin 1-beta (IL-1β), tumour necrosis factor-alpha (TNFα), IL-8 and IL-6. In the combination treatment, 0.5 mg/L CST reduced IL-1β, TNFα and IL-8 levels, whereas at 2 mg/L and 8 mg/L it increased the anti-inflammatory cytokine IL-10 (P < 0.05). Biofilm sub-MICs of CST enhance PMN killing capacity and attenuate production of inflammatory cytokines by MNCs exposed to CR-KpBF, playing a potentially important immunotherapeutic role especially for patients with cytokine deregulation.
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Abstract
Molecular mechanisms by which sex steroids interact with P. aeruginosa to modulate its virulence have yet to be reported. Our work provides the first characterization of a steroid-induced membrane stress mechanism promoting P. aeruginosa virulence, which includes the release of proinflammatory outer membrane vesicles, resulting in inflammation, host tissue damage, and reduced bacterial clearance. We further demonstrate that at nanomolar (physiological) concentrations, male and female sex steroids promote virulence in clinical strains of P. aeruginosa based on their dynamic membrane fluidic properties. This work provides, for the first-time, mechanistic insight to better understand and predict the P. aeruginosa related response to sex steroids and explain the interindividual patient variability observed in respiratory diseases such as cystic fibrosis that are complicated by gender differences and chronic P. aeruginosa infection. Estrogen, a major female sex steroid hormone, has been shown to promote the selection of mucoid Pseudomonas aeruginosa in the airways of patients with chronic respiratory diseases, including cystic fibrosis. This results in long-term persistence, poorer clinical outcomes, and limited therapeutic options. In this study, we demonstrate that at physiological concentrations, sex steroids, including testosterone and estriol, induce membrane stress responses in P. aeruginosa. This is characterized by increased virulence and consequent inflammation and release of proinflammatory outer membrane vesicles promoting in vivo persistence of the bacteria. The steroid-induced P. aeruginosa response correlates with the molecular polarity of the hormones and membrane fluidic properties of the bacteria. This novel mechanism of interaction between sex steroids and P. aeruginosa explicates the reported increased disease severity observed in females with cystic fibrosis and provides evidence for the therapeutic potential of the modulation of sex steroids to achieve better clinical outcomes in patients with hormone-responsive strains.
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17
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Transcriptomic determinants of the response of ST-111 Pseudomonas aeruginosa AG1 to ciprofloxacin identified by a top-down systems biology approach. Sci Rep 2020; 10:13717. [PMID: 32792590 PMCID: PMC7427096 DOI: 10.1038/s41598-020-70581-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/25/2020] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that thrives in diverse environments and causes a variety of human infections. Pseudomonas aeruginosa AG1 (PaeAG1) is a high-risk sequence type 111 (ST-111) strain isolated from a Costa Rican hospital in 2010. PaeAG1 has both blaVIM-2 and blaIMP-18 genes encoding for metallo-β-lactamases, and it is resistant to β-lactams (including carbapenems), aminoglycosides, and fluoroquinolones. Ciprofloxacin (CIP) is an antibiotic commonly used to treat P. aeruginosa infections, and it is known to produce DNA damage, triggering a complex molecular response. In order to evaluate the effects of a sub-inhibitory CIP concentration on PaeAG1, growth curves using increasing CIP concentrations were compared. We then measured gene expression using RNA-Seq at three time points (0, 2.5 and 5 h) after CIP exposure to identify the transcriptomic determinants of the response (i.e. hub genes, gene clusters and enriched pathways). Changes in expression were determined using differential expression analysis and network analysis using a top–down systems biology approach. A hybrid model using database-based and co-expression analysis approaches was implemented to predict gene–gene interactions. We observed a reduction of the growth curve rate as the sub-inhibitory CIP concentrations were increased. In the transcriptomic analysis, we detected that over time CIP treatment resulted in the differential expression of 518 genes, showing a complex impact at the molecular level. The transcriptomic determinants were 14 hub genes, multiple gene clusters at different levels (associated to hub genes or as co-expression modules) and 15 enriched pathways. Down-regulation of genes implicated in several metabolism pathways, virulence elements and ribosomal activity was observed. In contrast, amino acid catabolism, RpoS factor, proteases, and phenazines genes were up-regulated. Remarkably, > 80 resident-phage genes were up-regulated after CIP treatment, which was validated at phenomic level using a phage plaque assay. Thus, reduction of the growth curve rate and increasing phage induction was evidenced as the CIP concentrations were increased. In summary, transcriptomic and network analyses, as well as the growth curves and phage plaque assays provide evidence that PaeAG1 presents a complex, concentration-dependent response to sub-inhibitory CIP exposure, showing pleiotropic effects at the systems level. Manipulation of these determinants, such as phage genes, could be used to gain more insights about the regulation of responses in PaeAG1 as well as the identification of possible therapeutic targets. To our knowledge, this is the first report of the transcriptomic analysis of CIP response in a ST-111 high-risk P. aeruginosa strain, in particular using a top-down systems biology approach.
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Vitale A, Pessi G, Urfer M, Locher HH, Zerbe K, Obrecht D, Robinson JA, Eberl L. Identification of Genes Required for Resistance to Peptidomimetic Antibiotics by Transposon Sequencing. Front Microbiol 2020; 11:1681. [PMID: 32793157 PMCID: PMC7390954 DOI: 10.3389/fmicb.2020.01681] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/26/2020] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen and a leading cause of nosocomial infections. Due to its high intrinsic and adaptive resistance to antibiotics, infections caused by this organism are difficult to treat and new therapeutic options are urgently needed. Novel peptidomimetic antibiotics that target outer membrane (OM) proteins have shown great promise for the treatment of P. aeruginosa infections. Here, we have performed genome-wide mutant fitness profiling using transposon sequencing (Tn-Seq) to identify resistance determinants against the recently described peptidomimetics L27-11, compounds 3 and 4, as well as polymyxin B2 (PMB) and colistin (COL). We identified a set of 13 core genes that affected resistance to all tested antibiotics, many of which encode enzymes involved in the modification of the lipopolysaccharide (LPS) or control their expression. We also identified fitness determinants that are specific for antibiotics with similar structures that may indicate differences in their modes of action. These results provide new insights into resistance mechanisms against these peptide antibiotics, which will be important for future clinical development and efforts to further improve their potency.
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Affiliation(s)
- Alessandra Vitale
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | | | | | - Katja Zerbe
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | | | - John A Robinson
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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19
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Duperthuy M. Antimicrobial Peptides: Virulence and Resistance Modulation in Gram-Negative Bacteria. Microorganisms 2020; 8:microorganisms8020280. [PMID: 32092866 PMCID: PMC7074834 DOI: 10.3390/microorganisms8020280] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 02/03/2023] Open
Abstract
Growing resistance to antibiotics is one of the biggest threats to human health. One of the possibilities to overcome this resistance is to use and develop alternative molecules such as antimicrobial peptides (AMPs). However, an increasing number of studies have shown that bacterial resistance to AMPs does exist. Since AMPs are immunity molecules, it is important to ensure that their potential therapeutic use is not harmful in the long term. Recently, several studies have focused on the adaptation of Gram-negative bacteria to subinhibitory concentrations of AMPs. Such concentrations are commonly found in vivo and in the environment. It is therefore necessary to understand how bacteria detect and respond to low concentrations of AMPs. This review focuses on recent findings regarding the impact of subinhibitory concentrations of AMPs on the modulation of virulence and resistance in Gram-negative bacteria.
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Affiliation(s)
- Marylise Duperthuy
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Succ. Centre-ville, Montréal, QC H3C 3J7, Canada
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20
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Krce L, Šprung M, Maravić A, Umek P, Salamon K, Krstulović N, Aviani I. Bacteria Exposed to Silver Nanoparticles Synthesized by Laser Ablation in Water: Modelling E. coli Growth and Inactivation. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E653. [PMID: 32024125 PMCID: PMC7040691 DOI: 10.3390/ma13030653] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 12/19/2022]
Abstract
This study is aimed to better understand the bactericidal mode of action of silver nanoparticles. Here we present the production and characterization of laser-synthesized silver nanoparticles along with growth curves of bacteria treated at sub-minimal and minimal inhibitory concentrations, obtained by optical density measurements. The main effect of the treatment is the increase of the bacterial apparent lag time, which is very well described by the novel growth model as well as the entire growth curves for different concentrations. The main assumption of the model is that the treated bacteria uptake the nanoparticles and inactivate, which results in the decrease of both the nanoparticles and the bacteria concentrations. The lag assumes infinitive value for the minimal inhibitory concentration treatment. This apparent lag phase is not postponed bacterial growth. It is a dynamic state in which the bacterial growth and death rates are close in value. Our results strongly suggest that the predominant mode of antibacterial action of silver nanoparticles is the penetration inside the membrane.
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Affiliation(s)
- Lucija Krce
- Faculty of Science, Department of Physics, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Matilda Šprung
- Faculty of Science, Department of Chemistry, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Ana Maravić
- Faculty of Science, Department of Biology, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Polona Umek
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia;
| | - Krešimir Salamon
- Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia;
| | - Nikša Krstulović
- Institute of Physics, Bijenička cesta 46, 10000 Zagreb, Croatia;
| | - Ivica Aviani
- Faculty of Science, Department of Physics, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
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Reen FJ, McGlacken GP, O'Gara F. The expanding horizon of alkyl quinolone signalling and communication in polycellular interactomes. FEMS Microbiol Lett 2019; 365:4953739. [PMID: 29718276 DOI: 10.1093/femsle/fny076] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/25/2018] [Indexed: 02/07/2023] Open
Abstract
Population dynamics within natural ecosystems is underpinned by microbial diversity and the heterogeneity of host-microbe and microbe-microbe interactions. Small molecule signals that intersperse between species have been shown to govern many virulence-related processes in established and emerging pathogens. Understanding the capacity of microbes to decode diverse languages and adapt to the presence of 'non-self' cells will provide an important new direction to the understanding of the 'polycellular' interactome. Alkyl quinolones (AQs) have been described in the ESKAPE pathogen Pseudomonas aeruginosa, the primary agent associated with mortality in patients with cystic fibrosis and the third most prevalent nosocomial pathogen worldwide. The role of these molecules in governing the physiology and virulence of P. aeruginosa and other pathogens has received considerable attention, while a role in interspecies and interkingdom communication has recently emerged. Herein we discuss recent advances in our understanding of AQ signalling and communication in the context of microbe-microbe and microbe-host interactions. The integrated knowledge from these systems-based investigations will facilitate the development of new therapeutics based on the AQ framework that serves to disarm the pathogenesis of P. aeruginosa and competing pathogens.
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Affiliation(s)
- F Jerry Reen
- School of Microbiology, University College Cork, Cork, Ireland
| | - Gerard P McGlacken
- School of Chemistry and Analytical & Biological Chemistry Research Facility (ABCRF), University College Cork, Ireland
| | - Fergal O'Gara
- BIOMERIT Research Centre, School of Microbiology, University College Cork, Cork, Ireland
- Human Microbiome Programme, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, USA
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22
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Vasilchenko AS, Rogozhin EA. Sub-inhibitory Effects of Antimicrobial Peptides. Front Microbiol 2019; 10:1160. [PMID: 31178852 PMCID: PMC6543913 DOI: 10.3389/fmicb.2019.01160] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 05/07/2019] [Indexed: 01/01/2023] Open
Abstract
Antimicrobials, and particularly antimicrobial peptides (AMPs), have been thoroughly studied due to their therapeutic potential. The research on their exact mode of action on bacterial cells, especially at under sublethal concentrations, has resulted in a better understanding of the unpredictable nature of bacterial behavior under stress conditions. In this review, we were aiming to gather the wide yet still under-investigated knowledge about various AMPs and their subinhibition effects on cellular and molecular levels. We describe how AMP action is non-linear and unpredictable, also showing that exposure to AMP can lead to antimicrobial resistance via triggering various regulatory systems. Being one of the most known types of antimicrobials, bacteriocins have dual action and can also be utilized by microorganisms as signaling molecules at naturally achievable sub-inhibitory concentrations. The unpredictable nature of AMP action and the pathogenic response triggered by them remains an area of knowledge that requires further investigation.
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Affiliation(s)
- Alexey S. Vasilchenko
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia
| | - Eugene A. Rogozhin
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Gause Institute of New Antibiotics, Moscow, Russia
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23
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Inhibition of Protein Secretion in Escherichia coli and Sub-MIC Effects of Arylomycin Antibiotics. Antimicrob Agents Chemother 2019; 63:AAC.01253-18. [PMID: 30420476 DOI: 10.1128/aac.01253-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/04/2018] [Indexed: 12/31/2022] Open
Abstract
At sufficient concentrations, antibiotics effectively eradicate many bacterial infections. However, during therapy, bacteria are unavoidably exposed to lower antibiotic concentrations, and sub-MIC exposure can result in a wide variety of other effects, including the induction of virulence, which can complicate therapy, or horizontal gene transfer (HGT), which can accelerate the spread of resistance genes. Bacterial type I signal peptidase (SPase) is an essential protein that acts at the final step of the general secretory pathway. This pathway is required for the secretion of many proteins, including many required for virulence, and the arylomycins are a class of natural product antibiotics that target SPase. Here, we investigated the consequences of exposing Escherichia coli cultures to sub-MIC levels of an arylomycin. Using multidimensional protein identification technology mass spectrometry, we found that arylomycin treatment inhibits the proper extracytoplasmic localization of many proteins, both those that appear to be SPase substrates and several that do not. The identified proteins are involved in a broad range of extracytoplasmic processes and include a number of virulence factors. The effects of arylomycin on several processes required for virulence were then individually examined, and we found that, at even sub-MIC levels, the arylomycins potently inhibit flagellation, motility, biofilm formation, and the dissemination of antibiotic resistance via HGT. Thus, we conclude that the arylomycins represent promising novel therapeutics with the potential to eradicate infections while simultaneously reducing virulence and the dissemination of resistance.
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Lora-Tamayo J, Murillo O, Ariza J. Clinical Use of Colistin in Biofilm-Associated Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:181-195. [PMID: 31364079 DOI: 10.1007/978-3-030-16373-0_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Biofilm is an adaptive bacterial strategy whereby microorganisms become encased in a complex glycoproteic matrix. The low concentration of oxygen and nutrients in this environment leads to heterogeneous phenotypic changes in the bacteria, with antimicrobial tolerance being of paramount importance. As with other antibiotics, the activity of colistin is impaired by biofilm-embedded bacteria. Therefore, the recommendation for administering high doses in combination with a second drug, indicated for planktonic infections, remains valid in this setting. Notably, colistin has activity against metabolically inactive biofilm-embedded cells located in the inner layers of the biofilm structure. This is opposite and complementary to the activity of other antimicrobials that are able to kill metabolically active cells in the outer layers of the biofilm. Several experimental models have shown a higher activity of colistin when used in combination with other agents, and have reported that this can avoid the emergence of colistin-resistant subpopulations. Most experience of colistin in biofilm-associated infections comes from patients with cystic fibrosis, where the use of nebulized colistin allows high concentrations to reach the site of the infection. However, limited clinical experience is available in other scenarios, such as osteoarticular infections or device-related central nervous system infections caused by multi-drug resistant microorganisms. In the latter scenario, the use of intraventricular or intrathecal colistin also permits high local concentrations and good clinical results. Overall, the efficacy of intravenous colistin seems to be poor, but its association with a second antimicrobial significantly increases the response rate. Given its activity against inner bioflm-embedded cells, its possible role in combination with other antibiotics, beyond last-line therapy situations, should be further explored.
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Affiliation(s)
- Jaime Lora-Tamayo
- Department of Internal Medicine, Hospital Universitario 12 de Octubre, Madrid, Spain.
| | - Oscar Murillo
- Department of Infectious Diseases, Hospital Universitario de Bellvitge, Barcelona, Spain
| | - Javier Ariza
- Department of Infectious Diseases, Hospital Universitario de Bellvitge, Barcelona, Spain
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25
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26
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Morales-Soto N, Cao T, Baig NF, Kramer KM, Bohn PW, Shrout JD. Surface-Growing Communities of Pseudomonas aeruginosa Exhibit Distinct Alkyl Quinolone Signatures. Microbiol Insights 2018; 11:1178636118817738. [PMID: 30573968 PMCID: PMC6295745 DOI: 10.1177/1178636118817738] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 12/24/2022] Open
Abstract
A cascade of events leads to the development of microbial biofilm communities that are thought to be responsible for over 80% of infections in humans. However, not all surface-growing bacteria reside in a stationary biofilm state. Here, we have employed confocal Raman microscopy to analyze and compare variations in the alkyl quinolone (AQ) family of molecules during the transition between surface-attached motile-swarming and stationary biofilm communities. The AQs have been established previously as important to Pseudomonas aeruginosa biofilms, interspecies competition, and virulence. The AQ Pseudomonas quinolone signal (PQS) is also a known quorum-sensing signal. We detail spatial identification of AQ, PQS, and 2-alkyl-4-hydroxyquinoline N-oxide (AQNO) metabolites in both swarm and biofilm communities. We find that AQNO metabolites are abundant signatures in active swarming communities.
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Affiliation(s)
- Nydia Morales-Soto
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN, USA.,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Tianyuan Cao
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Nameera F Baig
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Kristen M Kramer
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN, USA.,Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Paul W Bohn
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN, USA.,Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, USA.,Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN, USA
| | - Joshua D Shrout
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN, USA.,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.,Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.,Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN, USA
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27
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Sousa AM, Monteiro R, Pereira MO. Unveiling the early events of Pseudomonas aeruginosa adaptation in cystic fibrosis airway environment using a long-term in vitro maintenance. Int J Med Microbiol 2018; 308:1053-1064. [PMID: 30377031 DOI: 10.1016/j.ijmm.2018.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/16/2018] [Accepted: 10/10/2018] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa chronic infections are the major cause of high morbidity and mortality in cystic fibrosis (CF) patients due to the use of sophisticated mechanisms of adaptation, including clonal diversification into specialized CF-adapted phenotypes. In contrast to chronic infections, very little is known about what occurs after CF lungs colonization and at early infection stages. This study aims to investigate the early events of P. aeruginosa adaptation to CF environment, in particular, to inspect the occurrence of clonal diversification at early stages of infection development and its impact on antibiotherapy effectiveness. To mimic CF early infections, three P. aeruginosa strains were long-term grown in artificial sputum (ASM) over 10 days and phenotypic diversity verified through colony morphology characterization. Biofilm sub- and inhibitory concentrations of ciprofloxacin were applied to non- and diversified populations to evaluate antibiotic effectiveness on P. aeruginosa eradication. Our results demonstrated that clonal diversification might occur after ASM colonization and growth. However, this phenotypic diversification did not compromise ciprofloxacin efficacy in P. aeruginosa eradication since a biofilm minimal inhibitory dosage would be applied. The expected absence of mutators in P. aeruginosa populations led us to speculate that clonal diversification in the absence of ciprofloxacin treatments could be driven by niche specialization. Yet, biofilm sub-inhibitory concentrations of ciprofloxacin seemed to overlap niche specialization as "fitter" variants emerged, such as mucoid, small colony and pinpoint variants, known to be highly resistant to antibiotics. The pathogenic potential of all emergent colony morphotypes-associated bacteria, distinct from the wild-morphotypes, revealed that P. aeruginosa evolved to a non-swimming phenotype. Impaired swimming motility seemed to be one of the first evolutionary steps of P. aeruginosa in CF lungs that could pave the way for further adaptation steps including biofilm formation and progress to chronic infection. Based on our findings, impaired swimming motility seemed to be a candidate to disease marker of P. aeruginosa infection development. Despite our in vitro CF model represents a step forward towards in vivo scenario simulation and provided valuable insights about the early events, more and distinct P. aeruginosa strains should be studied to strengthen our results.
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Affiliation(s)
- Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Rosana Monteiro
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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28
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O'Driscoll NH, Cushnie TPT, Matthews KH, Lamb AJ. Colistin causes profound morphological alteration but minimal cytoplasmic membrane perforation in populations of Escherichia coli and Pseudomonas aeruginosa. Arch Microbiol 2018; 200:793-802. [PMID: 29423561 PMCID: PMC6004271 DOI: 10.1007/s00203-018-1485-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/19/2018] [Accepted: 01/24/2018] [Indexed: 12/18/2022]
Abstract
Whilst colistin (polymyxin E) represents the last mainstream treatment option for multidrug-resistant Gram-negative pathogens, details of its mechanism of action remain to be fully resolved. In this study, the effects of sub-inhibitory, inhibitory-bactericidal, and supra-bactericidal levels of colistin on the membrane integrity and morphology of Escherichia coli and Pseudomonas aeruginosa were investigated using potassium loss, flow cytometry, and scanning electron microscopy (SEM). Supra-bactericidal colistin concentrations induced just 4-12% intracellular potassium loss from bacteria after 24 h. Flow cytometry data suggested colistin might alter cell arrangement, and SEM confirmed the antibiotic causes bacterial aggregation. Filamentation was not detected in either species at any concentration or time-point up to 24 h. These results argue against the hypotheses that colistin kills bacteria by puncturing the cytoplasmic membrane or disrupting DNA synthesis. The colistin-induced bacterial aggregation detected has implications for the interpretation of MBC, time-kill, and other test results obtained with this antibiotic.
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Affiliation(s)
- Noëlle H O'Driscoll
- School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Garthdee Road, Aberdeen, AB10 7GJ, UK
| | - T P Tim Cushnie
- Faculty of Medicine, Mahasarakham University, Khamriang, Kantarawichai, Maha Sarakham, 44150, Thailand
| | - Kerr H Matthews
- School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Garthdee Road, Aberdeen, AB10 7GJ, UK
| | - Andrew J Lamb
- School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Garthdee Road, Aberdeen, AB10 7GJ, UK.
- Graduate School, Robert Gordon University, Health and Social Care Building, Garthdee Road, Aberdeen, AB10 7QG, UK.
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29
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Morales-Soto N, Dunham SJB, Baig NF, Ellis JF, Madukoma CS, Bohn PW, Sweedler JV, Shrout JD. Spatially dependent alkyl quinolone signaling responses to antibiotics in Pseudomonas aeruginosa swarms. J Biol Chem 2018; 293:9544-9552. [PMID: 29588364 DOI: 10.1074/jbc.ra118.002605] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/22/2018] [Indexed: 11/06/2022] Open
Abstract
There is a general lack of understanding about how communities of bacteria respond to exogenous toxins such as antibiotics. Most of our understanding of community-level stress responses comes from the study of stationary biofilm communities. Although several community behaviors and production of specific biomolecules affecting biofilm development and associated behavior have been described for Pseudomonas aeruginosa and other bacteria, we have little appreciation for the production and dispersal of secreted metabolites within the 2D and 3D spaces they occupy as they colonize, spread, and grow on surfaces. Here we specifically studied the phenotypic responses and spatial variability of alkyl quinolones, including the Pseudomonas quinolone signal (PQS) and members of the alkyl hydroxyquinoline (AQNO) subclass, in P. aeruginosa plate-assay swarming communities. We found that PQS production was not a universal signaling response to antibiotics, as tobramycin elicited an alkyl quinolone response, whereas carbenicillin did not. We also found that PQS and AQNO profiles in response to tobramycin were markedly distinct and influenced these swarms on different spatial scales. At some tobramycin exposures, P. aeruginosa swarms produced alkyl quinolones in the range of 150 μm PQS and 400 μm AQNO that accumulated as aggregates. Our collective findings show that the distribution of alkyl quinolones can vary by several orders of magnitude within the same swarming community. More notably, our results suggest that multiple intercellular signals acting on different spatial scales can be triggered by one common cue.
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Affiliation(s)
- Nydia Morales-Soto
- From the Departments of Civil and Environmental Engineering and Earth Sciences
| | - Sage J B Dunham
- the Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | | | - Joseph F Ellis
- the Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Chinedu S Madukoma
- From the Departments of Civil and Environmental Engineering and Earth Sciences
| | - Paul W Bohn
- Chemistry and Biochemistry.,Chemical and Biomolecular Engineering, and
| | - Jonathan V Sweedler
- the Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Joshua D Shrout
- From the Departments of Civil and Environmental Engineering and Earth Sciences, .,Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556 and
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30
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Sub-minimum inhibitory concentrations of colistin and polymyxin B promote Acinetobacter baumannii biofilm formation. PLoS One 2018; 13:e0194556. [PMID: 29554105 PMCID: PMC5858813 DOI: 10.1371/journal.pone.0194556] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 03/06/2018] [Indexed: 01/29/2023] Open
Abstract
We investigated the numbers of planktonic and biofilm cells and the expression levels of genes encoding efflux pumps and biofilm-related proteins in 10 clinical isolates of multi-drug resistant Acinetobacter baumannii (MDRA) as well as in its standard strain ATCC 19606 in the presence of colistin (CST), polymyxin B (PMB), minomycin (MIN), and tigecycline (TGC) at their respective sub-MICs. The number of planktonic and biofilm cells of ATCC 19606 decreased in the presence of all aforementioned antibiotics in a dose-dependent manner. Cell number also decreased in two representative MDRA strains, R2 and R3, in the presence of MIN and TGC in a dose-dependent manner. In contrast, the number of biofilm cells in these two strains increased in the presence of CST, while they increased significantly in the presence of PMB in R2 only. Pearson correlation analysis revealed that the number of biofilm cells was positively and significantly correlated with the mRNA levels of genes encoding efflux pumps (adeB and adeG) and autoinducer synthase (abaI) in strain R2 and adeB, adeG, adeJ, poly-acetyl-glucosamine-porin (pgaA), and abaI in strain R3 in the presence of CST. It was positively and significantly correlated with the mRNA levels of genes encoding adeB in strain R2 and an outer membrane protein A (ompA) and biofilm-associated protein (bap) in strain R3 in the presence of PMB. These results provide valuable insights into the biofilm formation potency of clinical isolates of MDRA that depends on efflux pumps and biofilm-related genes and its regulation by antibiotics.
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31
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Abstract
Surface-attached colonies of bacteria known as biofilms play a major role in the pathogenesis of device-related infections. Biofilm colonies are notorious for their resistance to suprainhibitory concentrations of antibiotics. Numerous studies have shown that subminimal inhibitory concentrations of some antibiotics can act as agonists of bacterial biofilm formation in vitro, a process that may have clinical relevance. This article reviews studies demonstrating that low-dose antibiotics induce bacterial biofilm formation. These studies have provided important information about the regulation of biofilm formation and the signaling pathways involved in global gene regulation in response to cell stressors. It is still unclear whether antibiotic-induced biofilm formation contributes to the inconsistent success of antimicrobial therapy for device infections.
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32
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Rampioni G, Pillai CR, Longo F, Bondì R, Baldelli V, Messina M, Imperi F, Visca P, Leoni L. Effect of efflux pump inhibition on Pseudomonas aeruginosa transcriptome and virulence. Sci Rep 2017; 7:11392. [PMID: 28900249 PMCID: PMC5596013 DOI: 10.1038/s41598-017-11892-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/29/2017] [Indexed: 12/25/2022] Open
Abstract
Efflux pumps of the resistance-nodulation-cell-division (RND) family increase antibiotic resistance in many bacterial pathogens, representing candidate targets for the development of antibiotic adjuvants. RND pumps have also been proposed to contribute to bacterial infection, implying that efflux pump inhibitors (EPIs) could also act as anti-virulence drugs. Nevertheless, EPIs are usually investigated only for their properties as antibiotic adjuvants, while their potential anti-virulence activity is seldom taken into account. In this study it is shown that RND efflux pumps contribute to Pseudomonas aeruginosa PAO1 pathogenicity in an insect model of infection, and that the well-characterized EPI Phe-Arg-β-naphthylamide (PAβN) is able to reduce in vivo virulence of the P. aeruginosa PAO1 laboratory strain, as well as of clinical isolates. The production of quorum sensing (QS) molecules and of QS-dependent virulence phenotypes is differentially affected by PAβN, depending on the strain. Transcriptomic and phenotypic analyses showed that the protection exerted by PAβN from P. aeruginosa PAO1 infection in vivo correlates with the down-regulation of key virulence genes (e.g. genes involved in iron and phosphate starvation). Since PAβN impacts P. aeruginosa virulence, anti-virulence properties of EPIs are worthy to be explored, taking into account possible strain-specificity of their activity.
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Affiliation(s)
| | - Cejoice Ramachandran Pillai
- Department of Science, University Roma Tre, Rome, Italy
- Inter University Centre for Bioscience, Kannur University, Palayad, Kerala, India
| | | | - Roslen Bondì
- Department of Science, University Roma Tre, Rome, Italy
| | | | - Marco Messina
- Department of Science, University Roma Tre, Rome, Italy
| | - Francesco Imperi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Paolo Visca
- Department of Science, University Roma Tre, Rome, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy.
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33
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Wright MH, Fetzer C, Sieber SA. Chemical Probes Unravel an Antimicrobial Defense Response Triggered by Binding of the Human Opioid Dynorphin to a Bacterial Sensor Kinase. J Am Chem Soc 2017; 139:6152-6159. [PMID: 28350441 DOI: 10.1021/jacs.7b01072] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Host-microbe communication via small molecule signals is important for both symbiotic and pathogenic relationships, but is often poorly understood at the molecular level. Under conditions of host stress, levels of the human opioid peptide dynorphin are elevated, triggering virulence in the opportunistic pathogenic bacterium Pseudomonas aeruginosa via an unknown pathway. Here we apply a multilayered chemical biology strategy to unravel the mode of action of this putative interkingdom signal. We designed and applied dynorphin-inspired photoaffinity probes to reveal the protein targets of the peptide in live bacteria via chemical proteomics. ParS, a largely uncharacterized membrane sensor of a two-component system, was identified as the most promising hit. Subsequent full proteome studies revealed that dynorphin(1-13) induces an antimicrobial peptide-like response in Pseudomonas, with specific upregulation of membrane defense mechanisms. No such response was observed in a parS mutant, which was more susceptible to dynorphin-induced toxicity. Thus, P. aeruginosa exploits the ParS sensing machinery to defend itself against the host in response to dynorphin as a signal. This study highlights interkingdom communication as a potential essential strategy not only for induction of P. aeruginosa virulence but also for maintaining viability in the hostile environment of the host.
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Affiliation(s)
- Megan H Wright
- Department of Chemistry, Technical University of Munich , Lichtenbergstr. 4, D-85748 Garching, Germany
| | - Christian Fetzer
- Department of Chemistry, Technical University of Munich , Lichtenbergstr. 4, D-85748 Garching, Germany
| | - Stephan A Sieber
- Department of Chemistry, Technical University of Munich , Lichtenbergstr. 4, D-85748 Garching, Germany
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34
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Reen FJ, Flynn S, Woods DF, Dunphy N, Chróinín MN, Mullane D, Stick S, Adams C, O'Gara F. Bile signalling promotes chronic respiratory infections and antibiotic tolerance. Sci Rep 2016; 6:29768. [PMID: 27432520 PMCID: PMC4949476 DOI: 10.1038/srep29768] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/17/2016] [Indexed: 12/29/2022] Open
Abstract
Despite aggressive antimicrobial therapy, many respiratory pathogens persist in the lung, underpinning the chronic inflammation and eventual lung decline that are characteristic of respiratory disease. Recently, bile acid aspiration has emerged as a major comorbidity associated with a range of lung diseases, shaping the lung microbiome and promoting colonisation by Pseudomonas aeruginosa in Cystic Fibrosis (CF) patients. In order to uncover the molecular mechanism through which bile modulates the respiratory microbiome, a combination of global transcriptomic and phenotypic analyses of the P. aeruginosa response to bile was undertaken. Bile responsive pathways responsible for virulence, adaptive metabolism, and redox control were identified, with macrolide and polymyxin antibiotic tolerance increased significantly in the presence of bile. Bile acids, and chenodeoxycholic acid (CDCA) in particular, elicited chronic biofilm behaviour in P. aeruginosa, while induction of the pro-inflammatory cytokine Interleukin-6 (IL-6) in lung epithelial cells by CDCA was Farnesoid X Receptor (FXR) dependent. Microbiome analysis of paediatric CF sputum samples demonstrated increased colonisation by P. aeruginosa and other Proteobacterial pathogens in bile aspirating compared to non-aspirating patients. Together, these data suggest that bile acid signalling is a leading trigger for the development of chronic phenotypes underlying the pathophysiology of chronic respiratory disease.
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Affiliation(s)
- F Jerry Reen
- BIOMERIT Research Centre, School of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
| | - Stephanie Flynn
- BIOMERIT Research Centre, School of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
| | - David F Woods
- BIOMERIT Research Centre, School of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
| | - Niall Dunphy
- BIOMERIT Research Centre, School of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
| | | | - David Mullane
- Paediatric Cystic Fibrosis Unit, Cork University Hospital, Cork, Ireland
| | | | - Claire Adams
- BIOMERIT Research Centre, School of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
| | - Fergal O'Gara
- BIOMERIT Research Centre, School of Microbiology, University College Cork, National University of Ireland, Cork, Ireland.,Telethon Kids Institute, Perth, Western Australia.,School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, Australia
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35
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Cui B, Smooker PM, Rouch DA, Deighton MA. Effects of erythromycin on the phenotypic and genotypic biofilm expression in two clinical Staphylococcus capitis subspecies and a functional analysis of Ica proteins in S. capitis. J Med Microbiol 2015; 64:591-604. [DOI: 10.1099/jmm.0.000059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Bintao Cui
- School of Applied Sciences, RMIT University, Plenty Road, Bundoora, 3083 Victoria, Australia
| | - Peter M. Smooker
- School of Applied Sciences, RMIT University, Plenty Road, Bundoora, 3083 Victoria, Australia
| | - Duncan A. Rouch
- School of Applied Sciences, RMIT University, Plenty Road, Bundoora, 3083 Victoria, Australia
| | - Margaret A. Deighton
- School of Applied Sciences, RMIT University, Plenty Road, Bundoora, 3083 Victoria, Australia
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36
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Chua SL, Sivakumar K, Rybtke M, Yuan M, Andersen JB, Nielsen TE, Givskov M, Tolker-Nielsen T, Cao B, Kjelleberg S, Yang L. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth. Sci Rep 2015; 5:10052. [PMID: 25992876 PMCID: PMC4438720 DOI: 10.1038/srep10052] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/20/2015] [Indexed: 11/09/2022] Open
Abstract
Stress response plays an important role on microbial adaptation under hostile environmental conditions. It is generally unclear how the signaling transduction pathway mediates a stress response in planktonic and biofilm modes of microbial communities simultaneously. Here, we showed that metalloid tellurite (TeO3(2-)) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO3(2-) further increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth.
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Affiliation(s)
- Song Lin Chua
- 1] Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551 [2] NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore 117543
| | - Krishnakumar Sivakumar
- 1] Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551 [2] Interdisciplinary Graduate School, Nanyang Technological University, Singapore 637551
| | - Morten Rybtke
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 København N, Denmark
| | - Mingjun Yuan
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551
| | - Jens Bo Andersen
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 København N, Denmark
| | - Thomas E Nielsen
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551
| | - Michael Givskov
- 1] Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551 [2] Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 København N, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 København N, Denmark
| | - Bin Cao
- 1] Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551 [2] School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798
| | - Staffan Kjelleberg
- 1] Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551 [2] Center for Marine Bio-Innovation and School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia
| | - Liang Yang
- 1] Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551 [2] School of Biological Sciences, Nanyang Technological University, Singapore 637551
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37
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Reen FJ, Gutiérrez-Barranquero JA, Dobson ADW, Adams C, O’Gara F. Emerging concepts promising new horizons for marine biodiscovery and synthetic biology. Mar Drugs 2015; 13:2924-54. [PMID: 25984990 PMCID: PMC4446613 DOI: 10.3390/md13052924] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/22/2015] [Accepted: 04/28/2015] [Indexed: 12/23/2022] Open
Abstract
The vast oceans of the world, which comprise a huge variety of unique ecosystems, are emerging as a rich and relatively untapped source of novel bioactive compounds with invaluable biotechnological and pharmaceutical potential. Evidence accumulated over the last decade has revealed that the diversity of marine microorganisms is enormous with many thousands of bacterial species detected that were previously unknown. Associated with this diversity is the production of diverse repertoires of bioactive compounds ranging from peptides and enzymes to more complex secondary metabolites that have significant bioactivity and thus the potential to be exploited for innovative biotechnology. Here we review the discovery and functional potential of marine bioactive peptides such as lantibiotics, nanoantibiotics and peptidomimetics, which have received particular attention in recent years in light of their broad spectrum of bioactivity. The significance of marine peptides in cell-to-cell communication and how this may be exploited in the discovery of novel bioactivity is also explored. Finally, with the recent advances in bioinformatics and synthetic biology, it is becoming clear that the integration of these disciplines with genetic and biochemical characterization of the novel marine peptides, offers the most potential in the development of the next generation of societal solutions.
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Affiliation(s)
- F. Jerry Reen
- BIOMERIT Research Centre, School of Microbiology, University College Cork—National University of Ireland, Cork, Ireland; E-Mails: (F.J.R.); (J.A.G.-B.); (C.A.)
| | - José A. Gutiérrez-Barranquero
- BIOMERIT Research Centre, School of Microbiology, University College Cork—National University of Ireland, Cork, Ireland; E-Mails: (F.J.R.); (J.A.G.-B.); (C.A.)
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork—National University of Ireland, Cork, Ireland; E-Mail:
| | - Claire Adams
- BIOMERIT Research Centre, School of Microbiology, University College Cork—National University of Ireland, Cork, Ireland; E-Mails: (F.J.R.); (J.A.G.-B.); (C.A.)
| | - Fergal O’Gara
- BIOMERIT Research Centre, School of Microbiology, University College Cork—National University of Ireland, Cork, Ireland; E-Mails: (F.J.R.); (J.A.G.-B.); (C.A.)
- School of Biomedical Sciences, Curtin University, Perth WA 6845, Australia
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 899] [Impact Index Per Article: 99.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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Morita Y, Tomida J, Kawamura Y. Responses of Pseudomonas aeruginosa to antimicrobials. Front Microbiol 2014; 4:422. [PMID: 24409175 PMCID: PMC3884212 DOI: 10.3389/fmicb.2013.00422] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/24/2013] [Indexed: 11/29/2022] Open
Abstract
Infections caused by Pseudomonas aeruginosa often are hard to treat; inappropriate chemotherapy readily selects multidrug-resistant P. aeruginosa. This organism can be exposed to a wide range of concentrations of antimicrobials during treatment; learning more about the responses of P. aeruginosa to antimicrobials is therefore important. We review here responses of the bacterium P. aeruginosa upon exposure to antimicrobials at levels below the inhibitory concentration. Carbapenems (e.g., imipenem) have been shown to induce the formation of thicker and more robust biofilms, while fluoroquinolones (e.g., ciprofloxacin) and aminoglycosides (e.g., tobramycin) have been shown to induce biofilm formation. Ciprofloxacin also has been demonstrated to enhance the frequency of mutation to carbapenem resistance. Conversely, although macrolides (e.g., azithromycin) typically are not effective against P. aeruginosa because of the pseudomonal outer-membrane impermeability and efflux, macrolides do lead to a reduction in virulence factor production. Similarly, tetracycline is not very effective against this organism, but is known to induce the type-III secretion system and consequently enhance cytotoxicity of P. aeruginosain vivo. Of special note are the effects of antibacterials and disinfectants on pseudomonal efflux systems. Sub-inhibitory concentrations of protein synthesis inhibitors (aminoglycosides, tetracycline, chloramphenicol, etc.) induce the MexXY multidrug efflux system. This response is known to be mediated by interference with the translation of the leader peptide PA5471.1, with consequent effects on expression of the PA5471 gene product. Additionally, induction of the MexCD-OprJ multidrug efflux system is observed upon exposure to sub-inhibitory concentrations of disinfectants such as chlorhexidine and benzalkonium. This response is known to be dependent upon the AlgU stress response factor. Altogether, these biological responses of P. aeruginosa provide useful clues for the improvement and optimization of chemotherapy in order to appropriately treat pseudomonal infections while minimizing the emergence of resistance.
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Affiliation(s)
- Yuji Morita
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| | - Junko Tomida
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| | - Yoshiaki Kawamura
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
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Strempel N, Neidig A, Nusser M, Geffers R, Vieillard J, Lesouhaitier O, Brenner-Weiss G, Overhage J. Human host defense peptide LL-37 stimulates virulence factor production and adaptive resistance in Pseudomonas aeruginosa. PLoS One 2013; 8:e82240. [PMID: 24349231 PMCID: PMC3862677 DOI: 10.1371/journal.pone.0082240] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 10/21/2013] [Indexed: 12/02/2022] Open
Abstract
A multitude of different virulence factors as well as the ability to rapidly adapt to adverse environmental conditions are important features for the high pathogenicity of Pseudomonas aeruginosa. Both virulence and adaptive resistance are tightly controlled by a complex regulatory network and respond to external stimuli, such as host signals or antibiotic stress, in a highly specific manner. Here, we demonstrate that physiological concentrations of the human host defense peptide LL-37 promote virulence factor production as well as an adaptive resistance against fluoroquinolone and aminoglycoside antibiotics in P. aeruginosa PAO1. Microarray analyses of P. aeruginosa cells exposed to LL-37 revealed an upregulation of gene clusters involved in the production of quorum sensing molecules and secreted virulence factors (PQS, phenazine, hydrogen cyanide (HCN), elastase and rhamnolipids) and in lipopolysaccharide (LPS) modification as well as an induction of genes encoding multidrug efflux pumps MexCD-OprJ and MexGHI-OpmD. Accordingly, we detected significantly elevated levels of toxic metabolites and proteases in bacterial supernatants after LL-37 treatment. Pre-incubation of bacteria with LL-37 for 2 h led to a decreased susceptibility towards gentamicin and ciprofloxacin. Quantitative Realtime PCR results using a PAO1-pqsE mutant strain present evidence that the quinolone response protein and virulence regulator PqsE may be implicated in the regulation of the observed phenotype in response to LL-37. Further experiments with synthetic cationic antimicrobial peptides IDR-1018, 1037 and HHC-36 showed no induction of pqsE expression, suggesting a new role of PqsE as highly specific host stress sensor.
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Affiliation(s)
- Nikola Strempel
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
| | - Anke Neidig
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
| | - Michael Nusser
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
| | - Robert Geffers
- Helmholtz Center for Infection Research, Genome Analytics, Braunschweig, Germany
| | | | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen, Evreux, France
| | - Gerald Brenner-Weiss
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
| | - Joerg Overhage
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
- * E-mail:
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41
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Vaz Jauri P, Bakker MG, Salomon CE, Kinkel LL. Subinhibitory antibiotic concentrations mediate nutrient use and competition among soil streptomyces. PLoS One 2013; 8:e81064. [PMID: 24339897 PMCID: PMC3855208 DOI: 10.1371/journal.pone.0081064] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 10/08/2013] [Indexed: 11/23/2022] Open
Abstract
Though traditionally perceived as weapons, antibiotics are also hypothesized to act as microbial signals in natural habitats. However, while subinhibitory concentrations of antibiotics (SICA) are known to shift bacterial gene expression, specific hypotheses as to how SICA influence the ecology of natural populations are scarce. We explored whether antibiotic ‘signals’, or SICA, have the potential to alter nutrient utilization, niche overlap, and competitive species interactions among Streptomyces populations in soil. For nine diverse Streptomyces isolates, we evaluated nutrient utilization patterns on 95 different nutrient sources in the presence and absence of subinhibitory concentrations of five antibiotics. There were significant changes in nutrient use among Streptomyces isolates, including both increases and decreases in the capacity to use individual nutrients in the presence vs. in the absence of SICA. Isolates varied in their responses to SICA and antibiotics varied in their effects on isolates. Furthermore, for some isolate-isolate-antibiotic combinations, competition-free growth (growth for an isolate on all nutrients that were not utilized by a competing isolate), was increased in the presence of SICA, reducing the potential fitness cost of nutrient competition among those competitors. This suggests that antibiotics may provide a mechanism for bacteria to actively minimize niche overlap among competitors in soil. Thus, in contrast to antagonistic coevolutionary dynamics, antibiotics as signals may mediate coevolutionary displacement among coexisting Streptomyces, thereby hindering the emergence of antibiotic resistant phenotypes. These results contribute to our broad understanding of the ecology and evolutionary biology of antibiotics and microbial signals in nature.
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Affiliation(s)
- Patricia Vaz Jauri
- Department of Plant Pathology, University of Minnesota, Twin Cities, Minnesota, United States of America
- * E-mail:
| | - Matthew G. Bakker
- Department of Plant Pathology, University of Minnesota, Twin Cities, Minnesota, United States of America
| | - Christine E. Salomon
- Center for Drug Design, University of Minnesota, Twin Cities, Minnesota, United States of America
| | - Linda L. Kinkel
- Department of Plant Pathology, University of Minnesota, Twin Cities, Minnesota, United States of America
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42
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Sympatric inhibition and niche differentiation suggest alternative coevolutionary trajectories among Streptomycetes. ISME JOURNAL 2013; 8:249-56. [PMID: 24152720 DOI: 10.1038/ismej.2013.175] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 11/08/2022]
Abstract
Soil bacteria produce a diverse array of antibiotics, yet our understanding of the specific roles of antibiotics in the ecological and evolutionary dynamics of microbial interactions in natural habitats remains limited. Here, we show a significant role for antibiotics in mediating antagonistic interactions and nutrient competition among locally coexisting Streptomycete populations from soil. We found that antibiotic inhibition is significantly more intense among sympatric than allopatric Streptomycete populations, indicating local selection for inhibitory phenotypes. For sympatric but not allopatric populations, antibiotic inhibition is significantly positively correlated with niche overlap, indicating that inhibition is targeted toward bacteria that pose the greatest competitive threat. Our results support the hypothesis that antibiotics serve as weapons in mediating local microbial interactions in soil and suggest that coevolutionary niche displacement may reduce the likelihood of an antibiotic arms race. Further insight into the diverse roles of antibiotics in microbial ecology and evolution has significant implications for understanding the persistence of antibiotic inhibitory and resistance phenotypes in environmental microbes, optimizing antibiotic drug discovery and developing strategies for managing microbial coevolutionary dynamics to enhance inhibitory phenotypes.
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Wright EA, Fothergill JL, Paterson S, Brockhurst MA, Winstanley C. Sub-inhibitory concentrations of some antibiotics can drive diversification of Pseudomonas aeruginosa populations in artificial sputum medium. BMC Microbiol 2013; 13:170. [PMID: 23879797 PMCID: PMC3726342 DOI: 10.1186/1471-2180-13-170] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/19/2013] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Pseudomonas aeruginosa populations within the cystic fibrosis lung exhibit extensive phenotypic and genetic diversification. The resultant population diversity is thought to be crucial to the persistence of infection and may underpin the progression of disease. However, because cystic fibrosis lungs represent ecologically complex and hostile environments, the selective forces driving this diversification in vivo remain unclear. We took an experimental evolution approach to test the hypothesis that sub-inhibitory antibiotics can drive diversification of P. aeruginosa populations. Replicate populations of P. aeruginosa LESB58 were cultured for seven days in artificial sputum medium with and without sub-inhibitory concentrations of various clinically relevant antibiotics. We then characterised diversification with respect to 13 phenotypic and genotypic characteristics. RESULTS We observed that higher population diversity evolved in the presence of azithromycin, ceftazidime or colistin relative to antibiotic-free controls. Divergence occurred due to alterations in antimicrobial susceptibility profiles following exposure to azithromycin, ceftazidime and colistin. Alterations in colony morphology and pyocyanin production were observed following exposure to ceftazidime and colistin only. Diversification was not observed in the presence of meropenem. CONCLUSIONS Our study indicates that certain antibiotics can promote population diversification when present in sub-inhibitory concentrations. Hence, the choice of antibiotic may have previously unforeseen implications for the development of P. aeruginosa infections in the lungs of cystic fibrosis patients.
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Affiliation(s)
- Elli A Wright
- Institute of Infection and Global Health, University of Liverpool, The Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
| | - Joanne L Fothergill
- Institute of Infection and Global Health, University of Liverpool, The Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
- NIHR Biomedical Research Centre in Microbial Disease, University of Liverpool, Liverpool, UK
| | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7BE, UK
| | | | - Craig Winstanley
- Institute of Infection and Global Health, University of Liverpool, The Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
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Gulder TAM, Hong H, Correa J, Egereva E, Wiese J, Imhoff JF, Gross H. Isolation, structure elucidation and total synthesis of lajollamide A from the marine fungus Asteromyces cruciatus. Mar Drugs 2013; 10:2912-35. [PMID: 23342379 PMCID: PMC3528133 DOI: 10.3390/md10122912] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), 1N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the L-leucine and L-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.
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Affiliation(s)
- Tobias A. M. Gulder
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk Str. 1, Bonn 53121, Germany; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (T.A.M.G.); (H.G.); Tel.: +49-228-735797 (T.A.M.G.); Fax: +49-228-739712 (T.A.M.G.); Tel.: +49-7071-2976970 (H.G.); Fax: +49-7071-295250 (H.G.)
| | - Hanna Hong
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk Str. 1, Bonn 53121, Germany; E-Mail:
| | - Jhonny Correa
- Institute for Pharmaceutical Biology, University of Bonn, Nussallee 6, Bonn 53115, Germany; E-Mails: (J.C.); (E.E.)
| | - Ekaterina Egereva
- Institute for Pharmaceutical Biology, University of Bonn, Nussallee 6, Bonn 53115, Germany; E-Mails: (J.C.); (E.E.)
| | - Jutta Wiese
- Kieler Wirkstoff-Zentrum (KiWiZ) at the Helmholtz-Zentrum für Ozeanforschung GEOMAR, Am Kiel-Kanal 44, Kiel 24106, Germany; E-Mails: (J.W.); (J.F.I.)
| | - Johannes F. Imhoff
- Kieler Wirkstoff-Zentrum (KiWiZ) at the Helmholtz-Zentrum für Ozeanforschung GEOMAR, Am Kiel-Kanal 44, Kiel 24106, Germany; E-Mails: (J.W.); (J.F.I.)
| | - Harald Gross
- Institute for Pharmaceutical Biology, University of Tübingen, Auf der Morgenstelle 8, Tübingen 72076, Germany
- Authors to whom correspondence should be addressed; E-Mails: (T.A.M.G.); (H.G.); Tel.: +49-228-735797 (T.A.M.G.); Fax: +49-228-739712 (T.A.M.G.); Tel.: +49-7071-2976970 (H.G.); Fax: +49-7071-295250 (H.G.)
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Troppens DM, Chu M, Holcombe LJ, Gleeson O, O'Gara F, Read ND, Morrissey JP. The bacterial secondary metabolite 2,4-diacetylphloroglucinol impairs mitochondrial function and affects calcium homeostasis in Neurospora crassa. Fungal Genet Biol 2013; 56:135-46. [PMID: 23624246 DOI: 10.1016/j.fgb.2013.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/25/2013] [Accepted: 04/12/2013] [Indexed: 10/26/2022]
Abstract
The bacterial secondary metabolite 2,4-diacetylphloroglucinol (DAPG) is of interest as an active ingredient of biological control strains of Pseudomonas fluorescens and as a potential lead pharmaceutical molecule because of its capacity to inhibit growth of diverse microbial and non-microbial cells. The mechanism by which this occurs is unknown and in this study the filamentous fungus Neurospora crassa was used as a model to investigate the effects of DAPG on a eukaryotic cell. Colony growth, conidial germination and cell fusion assays confirmed the inhibitory nature of DAPG towards N. crassa. A number of different fluorescent dyes and fluorescent protein reporters were used to assess the effects of DAPG treatment on mitochondrial and other cellular functions. DAPG treatment led to changes in mitochondrial morphology, and rapid loss of mitochondrial membrane potential. These effects are likely to be responsible for the toxicity of DAPG. It was also found that DAPG treatment caused extracellular calcium to be taken up by conidial germlings leading to a transient increase in cytosolic free Ca(2+) with a distinct concentration dependent Ca(2+) signature.
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46
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Respiratory pathogens adopt a chronic lifestyle in response to bile. PLoS One 2012; 7:e45978. [PMID: 23049911 PMCID: PMC3458808 DOI: 10.1371/journal.pone.0045978] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
Abstract
Chronic respiratory infections are a major cause of morbidity and mortality, most particularly in Cystic Fibrosis (CF) patients. The recent finding that gastro-esophageal reflux (GER) frequently occurs in CF patients led us to investigate the impact of bile on the behaviour of Pseudomonas aeruginosa and other CF-associated respiratory pathogens. Bile increased biofilm formation, Type Six Secretion, and quorum sensing in P. aeruginosa, all of which are associated with the switch from acute to persistent infection. Furthermore, bile negatively influenced Type Three Secretion and swarming motility in P. aeruginosa, phenotypes associated with acute infection. Bile also modulated biofilm formation in a range of other CF-associated respiratory pathogens, including Burkholderia cepacia and Staphylococcus aureus. Therefore, our results suggest that GER-derived bile may be a host determinant contributing to chronic respiratory infection.
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47
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Zhou L, Reen FJ, O’Gara F, McSweeney CM, Clarke SL, Glennon JD, Luong JH, McGlacken GP. Analysis of pseudomonas quinolone signal and other bacterial signalling molecules using capillaries coated with highly charged polyelectrolyte monolayers and boron doped diamond electrode. J Chromatogr A 2012; 1251:169-175. [DOI: 10.1016/j.chroma.2012.06.064] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 01/30/2023]
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Thermodynamic interactions of a cis and trans benzanilide with Escherichia coli bacterial membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:687-93. [DOI: 10.1007/s00249-012-0835-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 06/15/2012] [Accepted: 06/22/2012] [Indexed: 10/28/2022]
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49
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Reen FJ, Clarke SL, Legendre C, McSweeney CM, Eccles KS, Lawrence SE, O'Gara F, McGlacken GP. Structure–function analysis of the C-3 position in analogues of microbial behavioural modulators HHQ and PQS. Org Biomol Chem 2012; 10:8903-10. [DOI: 10.1039/c2ob26823j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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50
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El-Halfawy OM, Valvano MA. Heteroresistance of opportunistic bacteria to antimicrobial peptides: a new challenge to antimicrobial therapy of cystic fibrosis infections. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/thy.11.69] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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