scholarly journals Photodynamic Inactivation of Legionella Pneumophila Biofilm Formation by Cationic Tetra- and Tripyridylporphyrins in Waters of Different Hardness

2021 ◽  
Vol 22 (16) ◽  
pp. 9095
Author(s):  
Martina Mušković ◽  
Iva Ćavar ◽  
Andrija Lesar ◽  
Martin Lončarić ◽  
Nela Malatesti ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
Water Hardness ◽  
Antimicrobial Effect ◽  
Growth Stages ◽  
Photodynamic Inactivation ◽  
Waterborne Diseases ◽  
Biofilm Growth ◽  
Biofilm Destruction

The bacterium Legionella pneumophila is still one of the probable causes of waterborne diseases, causing serious respiratory illnesses. In the aquatic systems, L. pneumophila exists inside free-living amoebae or can form biofilms. Currently developed disinfection methods are not sufficient for complete eradication of L. pneumophila biofilms in water systems of interest. Photodynamic inactivation (PDI) is a method that results in an antimicrobial effect by using a combination of light and a photosensitizer (PS). In this work, the effect of PDI in waters of natural origin and of different hardness, as a treatment against L. pneumophila biofilm, was investigated. Three cationic tripyridylporphyrins, which were previously described as efficient agents against L. pneumophila alone, were used as PSs. We studied how differences in water hardness affect the PSs’ stability, the production of singlet oxygen, and the PDI activity on L. pneumophila adhesion and biofilm formation and in biofilm destruction. Amphiphilic porphyrin showed a stronger tendency for aggregation in hard and soft water, but its production of singlet oxygen was higher in comparison to tri- and tetracationic hydrophilic porphyrins that were stable in all water samples. All three studied porphyrins were shown to be effective as PDI agents against the adhesion of the L. pneumophila to polystyrene, against biofilm formation, and in the destruction of the formed biofilm, in their micromolar concentrations. However, a higher number of dissolved ions, i.e., water hardness, generally reduced somewhat the PDI activity of all the porphyrins at all tested biofilm growth stages.

scholarly journals An In Vitro Coumarin-Antibiotic Combination Treatment of Pseudomonas aeruginosa Biofilms

2021 ◽  
Vol 16 (1) ◽  
pp. 1934578X2098774
Author(s):  
Jinpeng Zou ◽  
Yang Liu ◽  
Ruiwei Guo ◽  
Yu Tang ◽  
Zhengrong Shi ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Combination Treatment ◽  
Crude Extract ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antibacterial Properties ◽  
Biofilm Growth ◽  
Antibiotic Combination

The drug resistance of Pseudomonas aeruginosa is a worldwide problem due to its great threat to human health. A crude extract of Angelica dahurica has been proved to have antibacterial properties, which suggested that it may be able to inhibit the biofilm formation of P. aeruginosa; initial exploration had shown that the crude extract could inhibit the growth of P. aeruginosa effectively. After the adaptive dose of coumarin was confirmed to be a potential treatment for the bacteria’s drug resistance, “coumarin-antibiotic combination treatments” (3 coumarins—simple coumarin, imperatorin, and isoimperatorin—combined with 2 antibiotics—ampicillin and ceftazidime) were examined to determine their capability to inhibit P. aeruginosa. The final results showed that (1) coumarin with either ampicillin or ceftazidime significantly inhibited the biofilm formation of P. aeruginosa; (2) coumarin could directly destroy mature biofilms; and (3) the combination treatment can synergistically enhance the inhibition of biofilm formation, which could significantly reduce the usage of antibiotics and bacterial resistance. To sum up, a coumarin-antibiotic combination treatment may be a potential way to inhibit the biofilm growth of P. aeruginosa and provides a reference for antibiotic resistance treatment.

scholarly journals Detection of Protozoan Hosts for Legionella pneumophila in Engineered Water Systems by Using a Biofilm Batch Test

2010 ◽  
Vol 76 (21) ◽  
pp. 7144-7153 ◽  
Author(s):  
Rinske M. Valster ◽  
Bart A. Wullings ◽  
Dick van der Kooij
Keyword(s):  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Batch Test ◽  
Free Living ◽  
Water Types ◽  
Operational Taxonomic Units ◽  
Hartmannella Vermiformis

ABSTRACT Legionella pneumophila proliferates in aquatic habitats within free-living protozoa, 17 species of which have been identified as hosts by using in vitro experiments. The present study aimed at identifying protozoan hosts for L. pneumophila by using a biofilm batch test (BBT). Samples (600 ml) collected from 21 engineered freshwater systems, with added polyethylene cylinders to promote biofilm formation, were inoculated with L. pneumophila and subsequently incubated at 37°C for 20 days. Growth of L. pneumophila was observed in 16 of 18 water types when the host protozoan Hartmannella vermiformis was added. Twelve of the tested water types supported growth of L. pneumophila or indigenous Legionella anisa without added H. vermiformis. In 12 of 19 BBT flasks H. vermiformis was indicated as a host, based on the ratio between maximum concentrations of L. pneumophila and H. vermiformis, determined with quantitative PCR (Q-PCR), and the composition of clone libraries of partial 18S rRNA gene fragments. Analyses of 609 eukaryotic clones from the BBTs revealed that 68 operational taxonomic units (OTUs) showed the highest similarity to free-living protozoa. Forty percent of the sequences clustering with protozoa showed ≥99.5% similarity to H. vermiformis. None of the other protozoa serving as hosts in in vitro studies were detected in the BBTs. In several tests with growth of L. pneumophila, the protozoa Diphylleia rotans, Echinamoeba thermarum, and Neoparamoeba sp. were identified as candidate hosts. In vitro studies are needed to confirm their role as hosts for L. pneumophila. Unidentified protozoa were implicated as hosts for uncultured Legionella spp. grown in BBT flasks at 15°C.

Differential surface competition and biofilm invasion strategies of Pseudomonas aeruginosa PA14 and PAO1

2021 ◽  
Author(s):  
Swetha Kassety ◽  
Stefan Katharios-Lanwermeyer ◽  
George A. O’Toole ◽  
Carey D. Nadell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Matrix Composition ◽  
Model Organisms ◽  
Culture Methods ◽  
Biofilm Growth ◽  
Biofilm Production ◽  
Direct Competition ◽  
Planktonic Phase ◽  
Do So

Pseudomonas aeruginosa strains PA14 and PAO1 are among the two best characterized model organisms used to study the mechanisms of biofilm formation, while also representing two distinct lineages of P. aeruginosa . Previous work has shown that PA14 and PAO1 use different strategies for surface colonization; they also have different extracellular matrix composition and different propensities to disperse from biofilms back into the planktonic phase surrounding them. We expand on this work here by exploring the consequences of these different biofilm production strategies during direct competition. Using differentially labeled strains and microfluidic culture methods, we show that PAO1 can outcompete PA14 in direct competition during early colonization and subsequent biofilm growth, that they can do so in constant and perturbed environments, and that this advantage is specific to biofilm growth and requires production of the Psl polysaccharide. In contrast, the P. aeruginosa PA14 is better able to invade pre-formed biofilms and is more inclined to remain surface-associated under starvation conditions. These data together suggest that while P. aeruginosa PAO1 and PA14 are both able to effectively colonize surfaces, they do so in different ways that are advantageous under different environmental settings. Importance Recent studies indicate that P. aeruginosa PAO1 and PA14 use distinct strategies to initiate biofilm formation. We investigated whether their respective colonization and matrix secretion strategies impact their ability to compete under different biofilm-forming regimes. Our work shows that these different strategies do indeed impact how these strains fair in direct competition: PAO1 dominates during colonization of a naïve surface, while PA14 is more effective in colonizing a pre-formed biofilm. These data suggest that even for very similar microbes there can be distinct strategies to successfully colonize and persist on surfaces during the biofilm life cycle.

scholarly journals Oxygen tension during biofilm growth influences the efficacy antimicrobial agents

2016 ◽  
Vol 45 (5) ◽  
pp. 302-307 ◽  
Author(s):  
Raquel Pippi ANTONIAZZI ◽  
Gabriela Ocampo TROJAHN ◽  
Maísa CASARIN ◽  
Camilla Filippi dos Santos ALVES ◽  
Roberto Christ Vianna SANTOS ◽  
...  
Keyword(s):  
Green Tea ◽  
Oxygen Tension ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Dental Students ◽  
Low Oxygen ◽  
Biofilm Growth ◽  
Model Method ◽  
Colony Forming Units

Abstract Objective To compare the antimicrobial efficacy of a 0.12% chlorhexidine (CHX) and herbal green tea (Camellia sinensis) solution on established biofilms formed at different oxygen tensions in an in situ model. Method Twenty-five dental students were eligible for the study. In situ devices with standardized enamel specimens (ES) facing the palatal and buccal sides were inserted in the mouths of volunteers for a 7 day period. No agent was applied during the first four days. From the fifth day onward, both agents were applied to the test ES group and no agent was applied to the control ES group. After 7 days the ES fragments were removed from the devices, sonicated, plated on agar, and incubated for 24 h at 37 °C to determine and quantify the colony forming units (CFUs). Result CHX had significantly higher efficacy compared to green tea on the buccal (1330 vs. 2170 CFU/µL) and palatal (2250 vs. 2520 CFU/µL) ES. In addition, intragroup comparisons showed significantly higher efficacy in buccal ES over palatal ES (1330 vs. 2250 CFU/µL for CHX and 2170 vs, 2520 CFU/µL for CV) for both solutions. Analysis of the ES controls showed significantly higher biofilm formation in palatal ES compared to buccal ES. Conclusion CHX has higher efficacy than green tea on 4-day biofilms. The efficacy of both agents was reduced for biofilms grown in a low oxygen tension environment. Therefore, the oxygen tension environment seems to influence the efficacy of the tested agents.

scholarly journals Action ofCoriandrum sativumL. Essential Oil upon OralCandida albicansBiofilm Formation

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
V. F. Furletti ◽  
I. P. Teixeira ◽  
G. Obando-Pereda ◽  
R. C. Mardegan ◽  
A. Sartoratto ◽  
...  
Keyword(s):  
Essential Oil ◽  
Biofilm Formation ◽  
Plant Material ◽  
Inhibitory Concentration ◽  
Chemical Characterization ◽  
Synergistic Action ◽  
Biofilm Growth ◽  
Water Distillation ◽  
Microdilution Method

The efficacy of extracts and essential oils fromAllium tuberosum, Coriandrum sativum, Cymbopogon martini, Cymbopogon winterianus,andSantolina chamaecyparissuswas evaluated againstCandidaspp. isolates from the oral cavity of patients with periodontal disease. The most active oil was fractionated and tested againstC. albicansbiofilm formation. The oils were obtained by water-distillation and the extracts were prepared with macerated dried plant material. The Minimal Inhibitory Concentration—MIC was determined by the microdilution method. Chemical characterization of oil constituents was performed using Gas Chromatography and Mass Spectrometry (GC-MS). C. sativum activity oil upon cell and biofilm morphology was evaluated by Scanning Electron Microscopy (SEM). The best activities against planktonicCandidaspp. were observed for the essential oil and the grouped F8–10fractions fromC. sativum. The crude oil also affected the biofilm formation inC. albicanscausing a decrease in the biofilm growth. Chemical analysis of the F8–10fractions detected as major active compounds, 2-hexen-1-ol, 3-hexen-1-ol and cyclodecane. Standards of these compounds tested grouped provided a stronger activity than the oil suggesting a synergistic action from the major oil constituents. The activity ofC. sativumoil demonstrates its potential for a new natural antifungal formulation.

scholarly journals Biofilm-FormingStaphylococcus epidermidisExpressing Vancomycin Resistance Early after Adhesion to a Metal Surface

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Toshiyuki Sakimura ◽  
Shiro Kajiyama ◽  
Shinji Adachi ◽  
Ko Chiba ◽  
Akihiko Yonekura ◽  
...  
Keyword(s):  
Metal Surface ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Count ◽  
Fluorescence Staining ◽  
Biofilm Growth ◽  
Before And After ◽  
Viable Bacteria ◽  
Coverage Rates ◽  
Resistance Expression

We investigated biofilm formation and time of vancomycin (VCM) resistance expression after adhesion to a metal surface inStaphylococcus epidermidis. Biofilm-formingStaphylococcus epidermidiswith a VCM MIC of 1 μg/mL was used. The bacteria were made to adhere to a stainless steel washer and treated with VCM at different times and concentrations. VCM was administered 0, 2, 4, and 8 hours after adhesion. The amount of biofilm formed was evaluated based on the biofilm coverage rates (BCRs) before and after VCM administration, bacterial viability in biofilm was visually observed using the fluorescence staining method, and the viable bacterial count in biofilm was measured. The VCM concentration required to decrease BCR significantly compared with that of VCM-untreated bacteria was 4 μg/mL, even in the 0 hr group. In the 4 and 8 hr groups, VCM could not inhibit biofilm growth even at 1,024 μg/mL. In the 8 hr group, viable bacteria remained in biofilm at a count of 104CFU even at a high VCM concentration (1,024 μg/mL). It was suggested that biofilm-formingStaphylococcus epidermidisexpresses resistance to VCM early after adhesion to a metal surface. Resistance increased over time after adhesion as the biofilm formed, and strong resistance was expressed 4–8 hours after adhesion.

scholarly journals Disruption of c-di-GMP signaling networks unlocks cryptic expression of secondary metabolites during biofilm growth in Burkholderia pseudomallei

2021 ◽  
Author(s):  
Grace I Borlee ◽  
Mihnea R. Mangalea ◽  
Kevin H. Martin ◽  
Brooke A. Plumley ◽  
Samuel J. Golon ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Biofilm Formation ◽  
Burkholderia Pseudomallei ◽  
Gene Clusters ◽  
Etiologic Agent ◽  
Regulatory Control ◽  
Colony Morphology ◽  
Secretion Systems ◽  
Biofilm Growth ◽  
Conditional Expression

The regulation and production of secondary metabolites during biofilm growth of Burkholderia spp. is not well understood. To learn more about the crucial role and regulatory control of cryptic molecules produced during biofilm growth, we disrupted c-di-GMP signaling in Burkholderia pseudomallei, a soil-borne bacterial saprophyte and the etiologic agent of melioidosis. Our approach to these studies combined transcriptional profiling with genetic deletions that targeted key c-di-GMP regulatory components to characterize responses to changes in temperature. Mutational analyses and conditional expression studies of c-di-GMP genes demonstrates their contribution to phenotypes such as biofilm formation, colony morphology, motility, and expression of secondary metabolite biosynthesis when grown as a biofilm at different temperatures. RNA-seq analysis was performed at varying temperatures in a ΔII2523 mutant background that is responsive to temperature alterations resulting in hypo- and hyper- biofilm forming phenotypes. Differential regulation of genes was observed for polysaccharide biosynthesis, secretion systems, and nonribosomal peptide and polyketide synthase (NRPS/PKS) clusters in response to temperature changes. Deletion mutations of biosynthetic gene clusters (BGCs) clusters 2, 11, 14 (syrbactin), and 15 (malleipeptin) in wild-type and ΔII2523 backgrounds also reveals the contribution of these BGCs to biofilm formation and colony morphology in addition to inhibition of Bacillus subtilis and Rhizoctonia solani. Our findings suggest that II2523 impacts the regulation of genes that contribute to biofilm formation and competition. Characterization of cryptic BGCs under differing environmental conditions will allow for a better understanding of the role of secondary metabolites in the context of biofilm formation and microbe-microbe interactions.

scholarly journals Biofilm Formation and Methylene Blue-mediated Photodynamic Inactivation of Vibrio Parahaemolyticus in the Sea Food Industry

2020 ◽  
Vol 10 (3) ◽  
Author(s):  
Xiaoting Zhang ◽  
Qian Wu ◽  
Shuze Tang ◽  
William W Riley ◽  
Zhenqiang Chen
Keyword(s):  
Methylene Blue ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Vibrio Parahaemolyticus ◽  
Food Industry ◽  
Membrane Integrity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Photodynamic Inactivation ◽  
Log Reduction

This study was conducted to better understand the mechanism of Vibrio Parahaemolyticus biofilm formation and to assess the inactivation effects of methylene blue-mediated photodynamic inactivation (PDI) technology as a preventative measure. Optical microscopy, following crystal violet staining, was used to observe the kinetics of V. parahaemolyticus biofilm formation. The crystal violet-based assay was performed in microtiter plates, and it was employed to determine which factors were most influential in the formation of the biofilms. Colony counting and confocal laser scanning microscopy (CLSM) were used to test the inactivation effect of methylene blue-mediated photodynamic technology on the biofilms. V. parahaemolyticus has the ability to form biofilms, as evidenced by their immediate adherence to glass surfaces and rapid maturity, within 24 h. High (7%) or low (0.5%) salinity was not conducive to the formation of biofilms, and rotational speed greater than 130 rpm also inhibited the process. A 4.05 log reduction in the concentration of viable biofilm cells was obtained with 100 μg/mL methylene blue and 20 min irradiation (24.996 J/cm2), but planktonic cells were more susceptible to the methylene blue-mediated photodynamic reaction (5.46 log reduction). The results presented here show that the methylene blue-mediated PDI technology is an effective means to inactivate V. parahaemolyticus by disrupting its membrane integrity and to inhibit the pathogen’s formation of protective biofilms. This technology is a valid tool that can be used to enhance food safety in the sea food industry.

scholarly journals Understanding How Staphylococcal Autolysin Domains Interact With Polystyrene Surfaces

2021 ◽  
Vol 12 ◽  
Author(s):  
Radha P. Somarathne ◽  
Emily R. Chappell ◽  
Y. Randika Perera ◽  
Rahul Yadav ◽  
Joo Youn Park ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Limited Proteolysis ◽  
Cd Spectroscopy ◽  
Bacterial Attachment ◽  
Binding Interaction ◽  
Biofilm Growth ◽  
Source Of Infection ◽  
Structural Details

Biofilms, when formed on medical devices, can cause malfunctions and reduce the efficiency of these devices, thus complicating treatments and serving as a source of infection. The autolysin protein of Staphylococcus epidermidis contributes to its biofilm forming ability, especially on polystyrene surfaces. R2ab and amidase are autolysin protein domains thought to have high affinity to polystyrene surfaces, and they are involved in initial bacterial attachment in S. epidermidis biofilm formation. However, the structural details of R2ab and amidase binding to surfaces are poorly understood. In this study, we have investigated how R2ab and amidase influence biofilm formation on polystyrene surfaces. We have also studied how these proteins interact with polystyrene nanoparticles (PSNPs) using biophysical techniques. Pretreating polystyrene plates with R2ab and amidase domains inhibits biofilm growth relative to a control protein, indicating that these domains bind tightly to polystyrene surfaces and can block bacterial attachment. Correspondingly, we find that both domains interact strongly with anionic, carboxylate-functionalized as well as neutral, non-functionalized PSNPs, suggesting a similar binding interaction for nanoparticles and macroscopic surfaces. Both anionic and neutral PSNPs induce changes to the secondary structure of both R2ab and amidase as monitored by circular dichroism (CD) spectroscopy. These changes are very similar, though not identical, for both types of PSNPs, suggesting that carboxylate functionalization is only a small perturbation for R2ab and amidase binding. This structural change is also seen in limited proteolysis experiments, which exhibit substantial differences for both proteins when in the presence of carboxylate PSNPs. Overall, our results demonstrate that the R2ab and amidase domains strongly favor adsorption to polystyrene surfaces, and that surface adsorption destabilizes the secondary structure of these domains. Bacterial attachment to polystyrene surfaces during the initial phases of biofilm formation, therefore, may be mediated by aromatic residues, since these residues are known to drive adsorption to PSNPs. Together, these experiments can be used to develop new strategies for biofilm eradication, ensuring the proper long-lived functioning of medical devices.

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