Effects of Bacteriophage P100 at Different Concentrations on the Structural Parameters of Listeria monocytogenes Biofilms

2018 ◽  
Vol 81 (12) ◽  
pp. 2040-2044 ◽  
Author(s):  
CRISTINA RODRÍGUEZ-MELCÓN ◽  
ROSA CAPITA ◽  
CAMINO GARCÍA-FERNÁNDEZ ◽  
CARLOS ALONSO-CALLEJA
Keyword(s):  
Image Analysis ◽  
Listeria Monocytogenes ◽  
Laser Scanning ◽  
Digital Image Analysis ◽  
Surface Coverage ◽  
Structural Parameters ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Foodborne Diseases ◽  
Average Thickness

ABSTRACT Because listeriosis is one of the deadliest foodborne diseases, controlling and eradicating Listeria monocytogenes biofilms is a serious challenge for food safety. Biofilms (24 h old) formed on polystyrene by a L. monocytogenes strain of food origin were exposed for a further 24 h to 12 different concentrations (from 100 to 1011 PFU/mL) of the bacteriophage P100 (Listex P100). The structural parameters of biofilms were studied by using confocal laser scanning microscopy and digital image analysis. The biovolume in the observation field (14,121 μm2) of control (untreated) biofilms was 237,333.1 ± 2,692.6 μm3. The biomass of treated biofilms ranged from 164.7 ± 89.0 μm3 (biofilms exposed to 1010 PFU/mL) to 231,170.5 ± 15,142.0 μm3 (100 PFU/mL). The lowest biomass was achieved after treatment with 108 PFU/mL, with no further decrease in biovolume when higher phage concentrations were used. A strong (P < 0.001) correlation was found between phage concentration (log units) and biovolume (−0.965), surface coverage (−0.939), roughness (0.976), maximum thickness (−0.853), and average thickness (−0.965). Findings from this research suggest that bacteriophage P100 at concentrations equal to or greater than 8 log PFU/mL successfully removes L. monocytogenes biofilms from polystyrene surfaces.

scholarly journals Effect of Sodium Hypochlorite and Benzalkonium Chloride on the Structural Parameters of the Biofilms Formed by Ten Salmonella enterica Serotypes

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 154 ◽  
Author(s):  
Rosa Capita ◽  
Silvia Fernández-Pérez ◽  
Laura Buzón-Durán ◽  
Carlos Alonso-Calleja
Keyword(s):  
Sodium Hypochlorite ◽  
Salmonella Enterica ◽  
Benzalkonium Chloride ◽  
Laser Scanning ◽  
Surface Coverage ◽  
Structural Parameters ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Concentrations ◽  
Practical Field

The influence of the strain on the ability of Salmonella enterica to form biofilms on polystyrene was investigated by confocal laser scanning microscopy. The effects of sodium hypochlorite with 10% active chlorine (SHY; 25,000, 50,000, or 100,000 ppm), and benzalkonium chloride (BZK; 1000, 5000, or 10,000 ppm) on twenty-four-hour-old biofilms was also determined. The biofilms of ten Salmonella enterica isolates from poultry (S. Agona, S. Anatum, S. Enteritidis, S. Hadar, S. Infantis, S. Kentucky, S. Thompson, S. Typhimurium, monophasic variant of S. Typhimurium 1,4,(5),12:i:-, and S. Virchow) were studied. Biofilms produced by S. Anatum, S. Hadar, S. Kentucky, and S. Typhimurium showed a trend to have the largest biovolume and the greatest surface coverage and thickness. The smallest biofilms (P < 0.01) in the observation field (14.2 × 103 µm2) were produced by S. Enteritidis and S. 1,4,(5),12:i:- (average 12.9 × 103 ± 9.3 × 103 µm3) compared to the rest of the serotypes (44.4 × 103 ± 24.7 × 103 µm3). Biovolume and surface coverage decreased after exposure for ten minutes to SHY at 50,000 or 100,000 ppm and to BZK at 5000 or 10,000 ppm. However, the lowest concentrations of disinfectants increased biovolume and surface coverage in biofilms of several strains (markedly so in the case of BZK). The results from this study suggest that the use of biocides at low concentrations could represent a public health risk. Further research studies under practical field conditions should be appropriate to confirm these findings.

scholarly journals Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis

2021 ◽  
Author(s):  
Eva Nowak
Keyword(s):  
Image Analysis ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Reactor Performance ◽  
Sludge Flocs ◽  
P Limitation ◽  
Floc Structure ◽  
Compositional Changes

The purpose of this study was to characterize microbial floc structure and properties under phosphorus (P) limiting and non-limiting regimes. The P-limitation applied to the biomass did not significantly impact on reactor performance in terms of COD removal and MLSS. The composition of EPS was affected by the P-limitation with significantly increased accumulation of carbohydrates, uronic acids and proteins. CLSM and glycoconjugate mapping revealed that the relative abundance of α and β- N -acetylgalactosaminyl/galactopyranosyl and N -acetylglucosaminyl residues was affected by P-limitation, suggesting changes in microbial populations within the floc structure, which in turn could cause the compositional changes of EPS. The image analysis performed on CLSM images indicated that under non-limiting conditions the cell clumps within the floc were significantly smaller as compared to P-limiting conditions. The fractal dimension and porosity under limiting conditions were either significantly higher or lower than under P-rich conditions.

scholarly journals Confocal Laser Scanning Microscopy and Image Analysis for Elucidating Crumb and Crust Microstructure of Bran-Enriched South African Fried Dough and Batter

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 605 ◽  
Author(s):  
Oluwatoyin O. Onipe ◽  
Daniso Beswa ◽  
Afam I. O. Jideani
Keyword(s):  
Image Analysis ◽  
Laser Scanning ◽  
Polynomial Regression ◽  
Initial Moisture Content ◽  
Soxhlet Extraction ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cross Sectional ◽  
Linear Effect ◽  
Staining Protocol

A double staining protocol for image acquisition using confocal microscopy (CLSM) coupled with image analysis was employed to elucidate the crust and cross-sectional properties of fried dough. Penetrated oil by image analysis (POia), porosity and pore features were quantified from the cross-section micrographs. Crust surface roughness was measured using fractal metrics and fat content was determined by solvent extraction using the American Association of Cereal Chemists method. Crumb porosity ranged between 54.94%–81.84% and reduced (p < 0.05) with bran addition. Crumb pore sizes ranged from 0–475 µm with <1 circularity, indicating elliptical shape. POia values were notably higher (p < 0.05) than PO by Soxhlet extraction (POsox), except for wheat bran (WB) fried dough where the values of POia and POsox were closely ranked. The linear effect of initial moisture content and bran concentration showed a significant impact on the image properties. The mean fractal dimension (FD) decreased as initial moisture increased. The addition of WB caused a significant reduction in the FD of fried dough, while the opposite effect was noted for its oat bran counterpart. Due to non-collinearity of image properties (FD, POia and porosity), data were fitted to cubic polynomial regression with R2 values > 0.70. CLSM and image analysis were effective in measuring oil absorption and interpreting crumb properties of fried dough. The protocol used in this study can be applied to other thick deep-fried foods for qualitative observation and quantitative measurement of a specific physical or chemical property.

scholarly journals Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis

2021 ◽  
Author(s):  
Eva Nowak
Keyword(s):  
Image Analysis ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Reactor Performance ◽  
Sludge Flocs ◽  
P Limitation ◽  
Floc Structure ◽  
Compositional Changes

The purpose of this study was to characterize microbial floc structure and properties under phosphorus (P) limiting and non-limiting regimes. The P-limitation applied to the biomass did not significantly impact on reactor performance in terms of COD removal and MLSS. The composition of EPS was affected by the P-limitation with significantly increased accumulation of carbohydrates, uronic acids and proteins. CLSM and glycoconjugate mapping revealed that the relative abundance of α and β- N -acetylgalactosaminyl/galactopyranosyl and N -acetylglucosaminyl residues was affected by P-limitation, suggesting changes in microbial populations within the floc structure, which in turn could cause the compositional changes of EPS. The image analysis performed on CLSM images indicated that under non-limiting conditions the cell clumps within the floc were significantly smaller as compared to P-limiting conditions. The fractal dimension and porosity under limiting conditions were either significantly higher or lower than under P-rich conditions.

scholarly journals 1640. Toward New Anti-Biofilm Therapies: High Mobility Group Box 1 (HMGB1) Protein and Its Structural Variants Can Be Used to Disrupt Bacterial Biofilms (BBs)

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S46-S46
Author(s):  
Aspasia Katragkou ◽  
Lauren Warren ◽  
John Buzzo ◽  
Steven Goodman
Keyword(s):  
Laser Scanning ◽  
Structural Integrity ◽  
Public Health Problem ◽  
Full Length ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Major Public Health Problem ◽  
Average Thickness ◽  
Research Support

Abstract Background BB-related infections are a major public health problem, as they are notoriously refractory to current treatments. One of the defining characteristics of BBs is the extracellular polymeric substance (EPS). Extracellular DNA and the bacterial DNABII family of proteins are key components of EPS and are crucial for BBs structural integrity. It is known that targeting DNABII proteins disrupts BBs. We hypothesized that HMGB1, a DNA-binding eukaryotic protein, could affect BBs as it binds to the same DNA structures as the DNABII proteins. HMGB1 is comprised of 3 domains, A Box, B Box, and C tail, all of which have different functions. We aimed to determine in vitro the effects of HMGB1 and its individual domains against BBs. Methods Klebsiella pneumoniae (KP), a common cause of nosocomial infections, was used for all BBs disruption assays. Human recombinant full-length HMGB1 (rHMGB1; 1–215), a C45S mutation variant (mHMGB1) and the HMGB1 domains A Box (1–89), B Box (90–176), AB Boxes (1–176), B-linker Box (80–179), and B-linker Box C106S were expressed (in E. coli) and purified to &gt;95%. To evaluate the effect of rHMGB1 and the various domains on established BBs, each protein species (200 nM) was added to preformed BBs at 24 hours. At 40 hours the BBs were washed, stained with LIVE/DEAD®, visualized via confocal laser scanning microscopy and images were analyzed by COMSTAT to calculate average thickness and biomass. Results Exogenous rHMGB1 and its individual domains, with the exception of A Box caused a significant reduction (P &lt; 0.05) in average thickness (AT) and biomass (BM) of KP biofilms when compared with untreated KP biofilms (% reduction mean ± SE in AT: 44% ± 0.33, 75% ± 0.04, 63% ± 0.1, 77% ± 0.03, 64% ± 0.08, 54% ± 0.15 and in BM: 61% ± 0.01, 80% ± 0.01, 68% ± 0.02, 67% ± 0.01, 73% ± 0.02, 56% ± 0.02 induced by rHMGB1, mHMGB1, B-Box, B-linker Box, AB Boxes, and B-linker Box C106S, respectively). Conclusion Full-length recombinant HMGB1 was able to significantly disrupt established KP biofilms as were all truncated HMGB1 forms containing the B Box domain and could potentially be used as a therapeutic treatment for BB-related infections. Disclosures J. Buzzo, ProclaRx: Collaborator, Research support. S. Goodman, ProclaRx: Collaborator and Scientific Advisor, Research support.

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