Effect of Cu addition to low-alloy structural steel on the resistance against corrosion by the Pseudomonas aeruginosa biofilm

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhong Li ◽  
Qing Lei ◽  
Luyao Huang ◽  
Chao Liu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Electrochemical Analysis ◽  
Microbiologically Influenced Corrosion ◽  
Morphological Observation ◽  
Confocal Laser ◽  
Content Type ◽  
Antibacterial Performance

Purpose Low-alloy structural steels (LASS) face severe microbiologically influenced corrosion (MIC) in their service environments. To mitigate this issue, Cu is often used as an alloying element owing to its intrinsic antimicrobial activity. However, the antibacterial performance and biofilm resistance of Cu-containing LASS (Cu-LASS) are still unclear. This study aims to analyze the effect of Cu addition to 420 MP LASS on its MIC by the Pseudomonas aeruginosa biofilm. Design/methodology/approach Scanning electron microscope, confocal laser scanning microscope and X-ray photoelectron spectroscopy were used to analyze the surface morphology and composition of corrosion products. The antibacterial activities of Cu-LASS were analyzed by the spread-plate method. In addition, electrochemical analysis was conducted to characterize the corrosion behavior of the produced alloy. Findings Bacterial analysis and morphological observation confirmed a reduced sessile cell count and inactivation of the P. aeruginosa biofilm on the surface of Cu-LASS coupons. Electrochemical measurements showed that Cu-LASS exhibited large polarization and charge-transfer resistances, which indicated excellent MIC resistance. This significantly enhanced resistance to MIC could be explained by the synergistic effect of released Cu2+ from the Cu-LASS surface and immediate contact to Cu-rich phase in the surface and the release of Cu2+ ions from the Cu-LASS surface. Originality/value The effect of Cu addition on the MIC resistance and antibacterial performance of LASS is seldom reported. It is necessary to investigate the corrosion resistance of Cu-LASS and clarify its antibacterial mechanism. This paper fulfills this need.

scholarly journals Genetic determinants of Pseudomonas aeruginosa biofilm establishment

Microbiology ◽  
2010 ◽  
Vol 156 (2) ◽  
pp. 431-441 ◽  
Author(s):  
Mathias Müsken ◽  
Stefano Di Fiore ◽  
Andreas Dötsch ◽  
Rainer Fischer ◽  
Susanne Häussler
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Laser Scanning ◽  
Growth Conditions ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
Repair System ◽  
Ph Homeostasis ◽  
Genetic Determinants ◽  
Complex Process ◽  
Genes Encoding

The establishment of bacterial biofilms on surfaces is a complex process that requires various factors for each consecutive developmental step. Here we report the screening of the comprehensive Harvard Pseudomonas aeruginosa PA14 mutant library for mutants exhibiting an altered biofilm phenotype. We analysed the capability of all mutants to form biofilms at the bottom of a 96-well plate by the use of an automated confocal laser-scanning microscope and found 394 and 285 genetic determinants of reduced and enhanced biofilm production, respectively. Overall, 67 % of the identified mutants were affected within genes encoding hypothetical proteins, indicating that novel developmental pathways are likely to be dissected in the future. Nevertheless, a common theme that emerged from the analysis of the genes with a predicted function is that the establishment of a biofilm requires regulatory components that are involved in survival under microaerophilic growth conditions, arginine metabolism, alkyl-quinolone signalling, pH homeostasis and the DNA repair system.

scholarly journals Characterization of Mono- and Mixed-Culture Campylobacter jejuni Biofilms

2011 ◽  
Vol 78 (4) ◽  
pp. 1033-1038 ◽  
Author(s):  
Tuba Ica ◽  
Vildan Caner ◽  
Ozlem Istanbullu ◽  
Hung Duc Nguyen ◽  
Bulbul Ahmed ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Campylobacter Jejuni ◽  
Laser Scanning ◽  
Physiological State ◽  
Confocal Laser Scanning Microscope ◽  
Survival Strategies ◽  
Confocal Laser ◽  
Flow Rates ◽  
Content Type ◽  
Common Causes

ABSTRACTCampylobacter jejuni, one of the most common causes of human gastroenteritis, is a thermophilic and microaerophilic bacterium. These characteristics make it a fastidious organism, which limits its ability to survive outside animal hosts. Nevertheless,C. jejunican be transmitted to both humans and animals via environmental pathways, especially through contaminated water. Biofilms may play a crucial role in the survival of the bacterium under unfavorable environmental conditions. The goal of this study was to investigate survival strategies ofC. jejuniin mono- and mixed-culture biofilms. We grew monoculture biofilms ofC. jejuniand mixed-culture biofilms ofC. jejuniwithPseudomonas aeruginosa. We found that mono- and mixed-culture biofilms had significantly different structures and activities. MonocultureC. jejunibiofilms did not consume a measurable quantity of oxygen. Using a confocal laser scanning microscope (CLSM), we found that cells from monoculture biofilms were alive according to live/dead staining but that these cells were not culturable. In contrast, in mixed-culture biofilms,C. jejuniremained in a culturable physiological state. MonocultureC. jejunibiofilms could persist under lower flow rates (0.75 ml/min) but were unable to persist at higher flow rates (1 to 2.5 ml/min). In sharp contrast, mixed-culture biofilms were more robust and were unaffected by higher flow rates (2.5 ml/min). Our results indicate that biofilms provide an environmental refuge that is conducive to the survival ofC. jejuni.

scholarly journals Alginate Oligosaccharide-Induced Modification of the lasI-lasR and rhlI-rhlR Quorum-Sensing Systems in Pseudomonas aeruginosa

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Alison A. Jack ◽  
Saira Khan ◽  
Lydia C. Powell ◽  
Manon F. Pritchard ◽  
Konrad Beck ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Laser Scanning ◽  
Homoserine Lactone ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Mass Spectrometry Analysis ◽  
Confocal Laser ◽  
Steric Interaction ◽  
Content Type

ABSTRACT Pseudomonas aeruginosa plays a major role in many chronic infections. Its ability to readily form biofilms contributes to its success as an opportunistic pathogen and its resistance/tolerance to antimicrobial/antibiotic therapy. A low-molecular-weight alginate oligomer (OligoG CF-5/20) derived from marine algae has previously been shown to impair motility in P. aeruginosa biofilms and disrupt pseudomonal biofilm assembly. As these bacterial phenotypes are regulated by quorum sensing (QS), we hypothesized that OligoG CF-5/20 may induce alterations in QS signaling in P. aeruginosa . QS regulation was studied by using Chromobacterium violaceum CV026 biosensor assays that showed a significant reduction in acyl homoserine lactone (AHL) production following OligoG CF-5/20 treatment (≥2%; P < 0.05). This effect was confirmed by liquid chromatography-mass spectrometry analysis of C 4 -AHL and 3-oxo-C 12 -AHL production (≥2%; P < 0.05). Moreover, quantitative PCR showed that reduced expression of both the las and rhl systems was induced following 24 h of treatment with OligoG CF-5/20 (≥0.2%; P < 0.05). Circular dichroism spectroscopy indicated that these alterations were not due to steric interaction between the AHL and OligoG CF-5/20. Confocal laser scanning microscopy (CLSM) and COMSTAT image analysis demonstrated that OligoG CF-5/20-treated biofilms had a dose-dependent decrease in biomass that was associated with inhibition of extracellular DNA synthesis (≥0.5%; P < 0.05). These changes correlated with alterations in the extracellular production of the pseudomonal virulence factors pyocyanin, rhamnolipids, elastase, and total protease ( P < 0.05). The ability of OligoG CF-5/20 to modify QS signaling in P. aeruginosa PAO1 may influence critical downstream functions such as virulence factor production and biofilm formation.

scholarly journals Dynamics of the Action of Biocides in Pseudomonas aeruginosa Biofilms

2011 ◽  
Vol 55 (6) ◽  
pp. 2648-2654 ◽  
Author(s):  
A. Bridier ◽  
F. Dubois-Brissonnet ◽  
G. Greub ◽  
V. Thomas ◽  
R. Briandet
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Laser Scanning ◽  
Biochemical Analysis ◽  
Laser Scanning Microscopy ◽  
Diffusion Reaction ◽  
Confocal Laser ◽  
Staining Procedure ◽  
Fluorescence Staining ◽  
Content Type ◽  
Real Time Visualization

ABSTRACTThe biocidal activity of peracetic acid (PAA) and benzalkonium chloride (BAC) onPseudomonas aeruginosabiofilms was investigated by using a recently developed confocal laser scanning microscopy (CLSM) method that enables the direct and real-time visualization of cell inactivation within the structure. This technique is based on monitoring the loss of fluorescence that corresponds to the leakage of a fluorophore out of cells due to membrane permeabilization by the biocides. Although this approach has previously been used with success with various Gram-positive species, it is not directly applicable to the visualization of Gram-negative strains such asP. aeruginosa, particularly because of limitations regarding fluorescence staining. After adapting the staining procedure toP. aeruginosa, the action of PAA and BAC on the biofilm formed by strain ATCC 15442 was investigated. The results revealed specific inactivation patterns as a function of the mode of action of the biocides. While PAA treatment triggered a uniform loss of fluorescence in the structure, the action of BAC was first localized at the periphery of cell clusters and then gradually spread throughout the biofilm. Visualization of the action of BAC in biofilms formed by three clinical isolates then confirmed the presence of a delay in penetration, showing that diffusion-reaction limitations could provide a major explanation for the resistance ofP. aeruginosabiofilms to this biocide. Biochemical analysis suggested a key role for extracellular matrix characteristics in these processes.

scholarly journals Electrochemical and surface analytical techniques applied to microbiologically influenced corrosion investigation

2018 ◽  
Vol 36 (4) ◽  
pp. 349-363 ◽  
Author(s):  
László Trif ◽  
Abdul Shaban ◽  
Judit Telegdi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Analytical Techniques ◽  
Laser Scanning Microscopy ◽  
Microbiologically Influenced Corrosion ◽  
Microbial Consortia ◽  
Confocal Laser ◽  
The Impact

AbstractSuitable application of techniques for detection and monitoring of microbiologically influenced corrosion (MIC) is crucial for understanding the mechanisms of the interactions and for selecting inhibition and control approaches. This paper presents a review of the application of electrochemical and surface analytical techniques in studying the MIC process of metals and their alloys. Conventional electrochemical techniques, such as corrosion potential (Ecorr), redox potential, dual-cell technique, polarization curves, electrochemical impedance spectroscopy (EIS), electrochemical noise (EN) analysis, and microelectrode techniques, are discussed, with examples of their use in various MIC studies. Electrochemical quartz crystal microbalance, which is newly used in MIC study, is also discussed. Microscopic techniques [scanning electron microscopy (SEM), environmental SEM (ESEM), atomic force microscopy (AFM), confocal laser microscopy (CLM), confocal laser scanning microscopy (CLSM), confocal Raman microscopy] and spectroscopic analytical methods [Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS)] are also highlighted. This review highlights the heterogeneous characteristics of microbial consortia and use of special techniques to study their probable effects on the metal substrata. The aim of this review is to motivate using a combination of new procedures for research and practical measurement and calculation of the impact of MIC and biofilms on metals and their alloys.

scholarly journals Sequential Treatment of Biofilms with Aztreonam and Tobramycin Is a Novel Strategy for Combating Pseudomonas aeruginosa Chronic Respiratory Infections

2016 ◽  
Vol 60 (5) ◽  
pp. 2912-2922 ◽  
Author(s):  
Estrella Rojo-Molinero ◽  
María D. Macià ◽  
Rosa Rubio ◽  
Bartolomé Moyà ◽  
Gabriel Cabot ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Laser Scanning ◽  
Bactericidal Effect ◽  
Cell System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Content Type ◽  
Inhaled Antibiotics ◽  
Resistant Mutants

ABSTRACTTraditional therapeutic strategies to control chronic colonization in cystic fibrosis (CF) patients are based on the use of a single nebulized antibiotic. In this study, we evaluated the therapeutic efficacy and dynamics of antibiotic resistance inPseudomonas aeruginosabiofilms under sequential therapy with inhaled aztreonam (ATM) and tobramycin (TOB). Laboratory strains PAO1, PAOMS (hypermutable), PAOMA (mucoid), and PAOMSA (mucoid and hypermutable) and two hypermutable CF strains, 146-HSE (Liverpool epidemic strain [LES-1]) and 1089-HSE (ST1089), were used. Biofilms were developed using the flow cell system. Mature biofilms were challenged with peak and 1/10-peak concentrations of ATM (700 mg/liter and 70 mg/liter), TOB (1,000 mg/liter and 100 mg/liter), and their alternations (ATM/TOB/ATM and TOB/ATM/TOB) for 2 (t= 2), 4 (t= 4), and 6 days (t= 6). The numbers of viable cells (CFU) and resistant mutants were determined. Biofilm structural dynamics were monitored by confocal laser scanning microscopy and processed with COMSTAT and IMARIS software programs. TOB monotherapy produced an intense decrease in CFU that was not always correlated with a reduction in biomass and/or a bactericidal effect on biofilms, particularly for the CF strains. The ATM monotherapy bactericidal effect was lower, but effects on biofilm biomass and/or structure, including intense filamentation, were documented. The alternation of TOB and ATM led to an enhancement of the antibiofilm activity against laboratory and CF strains compared to that with the individual regimens, potentiating the bactericidal effect and/or the reduction in biomass, particularly at peak concentrations. Resistant mutants were not documented in any of the regimens at the peak concentrations and only anecdotally at the 1/10-peak concentrations. These results support the clinical evaluation of sequential regimens with inhaled antibiotics in CF, as opposed to the current maintenance treatments with just one antibiotic in monotherapy.

scholarly journals Dynamics of Mutator and Antibiotic-Resistant Populations in a Pharmacokinetic/Pharmacodynamic Model of Pseudomonas aeruginosa Biofilm Treatment

2011 ◽  
Vol 55 (11) ◽  
pp. 5230-5237 ◽  
Author(s):  
María D. Macià ◽  
José L. Pérez ◽  
Soeren Molin ◽  
Antonio Oliver
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Resistance Development ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Mutant Prevention Concentration ◽  
Resistant Mutants

ABSTRACTBiofilm growth, antibiotic resistance, and mutator phenotypes are key components of chronic respiratory infections byPseudomonas aeruginosain cystic fibrosis patients. We examined the dynamics of mutator and antibiotic-resistant populations inP. aeruginosaflow-cell biofilms, using fluorescently tagged PAO1 and PAOMS (mutator [mutS] derivative) strains. Two-day-old biofilms were treated with ciprofloxacin (CIP) for 4 days (t4) at 2 μg/ml, which correlated with the mutant prevention concentration (MPC) and provided an AUC/MIC ratio of 384 that should predict therapeutic success. Biofilms were monitored by confocal laser scanning microscopy (CLSM), and the numbers of viable cells and resistant mutants (4- and 16-fold MICs) were determined. Despite optimized pharmacokinetic/pharmacodynamic (PK/PD) parameters, CIP treatment did not suppress resistance development inP. aeruginosabiofilms. One-step resistant mutants (MexCD-OprJ or MexEF-OprN overexpression) were selected for both strains, while two-step resistant mutants (additional GyrA or GyrB mutation) were readily selected only from the mutator strain. CLSM analysis of competition experiments revealed that PAOMS, even when inoculated at a 0.01 proportion, took over the whole biofilm after only 2 days of CIP treatment outnumbering PAO1 by 3 log at t4. Our results show that mutational mechanisms play a major role in biofilm antibiotic resistance and that theoretically optimized PK/PD parameters fail to suppress resistance development, suggesting that the increased antibiotic tolerance driven by the special biofilm physiology and architecture may raise the effective MPC, favoring gradual mutational resistance development, especially in mutator strains. Moreover, the amplification of mutator populations under antibiotic treatment by coselection with resistance mutations is for the first time demonstratedin situforP. aeruginosabiofilms.

scholarly journals Double-Encapsulated Microcapsules for the Adsorption to Cotton Fabrics

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 426
Author(s):  
Zuobing Xiao ◽  
Wenwen Xu ◽  
Jiajia Ma ◽  
Yi Zhao ◽  
Yunwei Niu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Spherical Shape ◽  
Confocal Laser Scanning Microscope ◽  
Cotton Fabrics ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Average Particle ◽  
Scanning Microscope ◽  
Laser Scanning Microscope

Double-encapsulated microcapsules (DEMs) were prepared and effectively adsorbed onto the cotton fabric surfaces during impregnation without crosslinking agents to obtain functional cotton fabrics. Specifically, Fourier transform infrared spectrometer (FTIR) and confocal laser scanning microscope (CLSM) showed two different molecules (lavender essence and dye indigo) were encapsulated into the microcapsules simultaneously, with loading capacity of 10% and 9.73%, respectively. The spherical shape of DEMs was confirmed by transmission electron microscopy (TEM), confocal laser scanning microscope (CLSM) and average particle sizes were about 617 nm, as measured by dynamic light scattering (DLS). According to the results of IR and X-ray photoelectron spectroscopy (XPS) experiments, DEMs was combined with cotton fabrics by hydrogen bond. The superior thermal stability of microcapsules and functional cotton fabrics was also demonstrated. The adsorption behavior and mechanism of microparticles onto cotton fabrics were further examined by chemical property characterization in combination with adsorption kinetic model. The kinetic adsorption process included three stages: fast adsorption, slow adsorption rate, and adsorption equilibrium. Finally, the good color fastness of the functional cotton fabrics was demonstrated by the tests of rubbing and accelerated laundering. Herein, this study will be beneficial to the development of functional cotton fabrics-based materials.

scholarly journals Interactions between Polymorphonuclear Leukocytes and Pseudomonas aeruginosa Biofilms on Silicone ImplantsIn Vivo

2012 ◽  
Vol 80 (8) ◽  
pp. 2601-2607 ◽  
Author(s):  
Maria van Gennip ◽  
Louise Dahl Christensen ◽  
Morten Alhede ◽  
Klaus Qvortrup ◽  
Peter Østrup Jensen ◽  
...  
Keyword(s):  
Immune Response ◽  
Pseudomonas Aeruginosa ◽  
Polymorphonuclear Leukocytes ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Chronic Infections ◽  
Content Type ◽  
Biofilm Development

ABSTRACTChronic infections withPseudomonas aeruginosapersist because the bacterium forms biofilms that are tolerant to antibiotic treatment and the host immune response. Scanning electron microscopy and confocal laser scanning microscopy were used to visualize biofilm developmentin vivofollowing intraperitoneal inoculation of mice with bacteria growing on hollow silicone tubes, as well as to examine the interaction between these bacteria and the host innate immune response. Wild-typeP. aeruginosadeveloped biofilms within 1 day that trapped and caused visible cavities in polymorphonuclear leukocytes (PMNs). In contrast, the number of cells of aP. aeruginosa rhlAmutant that cannot produce rhamnolipids was significantly reduced on the implants by day 1, and the bacteria were actively phagocytosed by infiltrating PMNs. In addition, we identified extracellular wire-like structures around the bacteria and PMNs, which we found to consist of DNA and other polymers. Here we present a novel method to study a pathogen-host interaction in detail. The data presented provide the first direct, high-resolution visualization of the failure of PMNs to protect against bacterial biofilms.

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