scholarly journals Impact of Environmental and Genetic Factors on Biofilm Formation by the Probiotic Strain Lactobacillus rhamnosus GG

2007 ◽  
Vol 73 (21) ◽  
pp. 6768-6775 ◽  
Author(s):  
Sarah Lebeer ◽  
Tine L. A. Verhoeven ◽  
M�nica Perea V�lez ◽  
Jos Vanderleyden ◽  
Sigrid C. J. De Keersmaecker
Keyword(s):  
Biofilm Formation ◽  
Culture Medium ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Strain ◽  
Lipoteichoic Acid ◽  
Microtiter Plate ◽  
Phenotypic Analysis ◽  
Lactobacillus Rhamnosus Gg ◽  
Abiotic Surfaces

ABSTRACTLactobacillus rhamnosusGG (ATCC 53103) is one of the clinically best-studied probiotic organisms. Moreover,L. rhamnosusGG displays very good in vitro adherence to epithelial cells and mucus. Here, we report thatL. rhamnosusGG is able to form biofilms on abiotic surfaces, in contrast to other strains of theLactobacillus caseigroup tested under the same conditions. Microtiter plate biofilm assays indicated that in vitro biofilm formation byL. rhamnosusGG is strongly modulated by culture medium factors and conditions related to the gastrointestinal environment, including low pH; high osmolarity; and the presence of bile, mucins, and nondigestible polysaccharides. Additionally, phenotypic analysis of mutants affected in exopolysaccharides (wzb), lipoteichoic acid (dltD), and central metabolism (luxS) showed their relative importance in biofilm formation byL. rhamnosusGG.

scholarly journals Functional Analysis of d-Alanylation of Lipoteichoic Acid in the Probiotic Strain Lactobacillus rhamnosus GG

2007 ◽  
Vol 73 (11) ◽  
pp. 3595-3604 ◽  
Author(s):  
Mónica Perea Vélez ◽  
Tine L. A. Verhoeven ◽  
Christian Draing ◽  
Sonja Von Aulock ◽  
Markus Pfitzenmaier ◽  
...  
Keyword(s):  
Lactobacillus Rhamnosus ◽  
Probiotic Strain ◽  
Lipoteichoic Acid ◽  
Nuclear Magnetic Resonance Analysis ◽  
Intestinal Epithelial ◽  
Human Intestinal Epithelial Cells ◽  
Insertional Inactivation ◽  
Survival Capacity ◽  
Increased Sensitivity

ABSTRACT Lipoteichoic acid (LTA) is a macroamphiphile molecule which performs several functions in gram-positive bacteria, such as maintenance of cell wall homeostasis. d-Alanylation of LTA requires the proteins encoded by the dlt operon, and this process is directly related to the charge properties of this polymer strongly contributing to its function. The insertional inactivation of dltD of the probiotic strain Lactobacillus rhamnosus GG (ATCC 53103) resulted in the complete absence of d-alanyl esters in the LTA as confirmed by nuclear magnetic resonance analysis. This was reflected in modifications of the bacterial cell surface properties. The dltD strain showed 2.4-fold-increased cell length, a low survival capacity in response to gastric juice challenge, an increased sensitivity to human beta-defensin-2, an increased rate of autolysis, an increased capacity to initiate growth in the presence of an anionic detergent, and a decreased capacity to initiate growth in the presence of cationic peptides compared to wild-type results. However, in vitro experiments revealed no major differences for adhesion to human intestinal epithelial cells, biofilm formation, and immunomodulation. These properties are considered to be important for probiotics. The role of the dlt operon in lactobacilli is discussed in view of these results.

scholarly journals Combined effect of arginine and fluoride on the growth of Lactobacillus rhamnosus GG

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammed Nadeem Bijle ◽  
Manikandan Ekambaram ◽  
Edward C. M. Lo ◽  
Cynthia Kar Yung Yiu
Keyword(s):  
Biofilm Formation ◽  
Lactobacillus Rhamnosus ◽  
In Vitro Study ◽  
Lactobacillus Rhamnosus Gg ◽  
Biofilm Growth ◽  
Biofilm Thickness ◽  
Colony Forming Units ◽  
Monosodium Salt ◽  
Relative Gene

AbstractThe objectives of the in vitro study were: (1) to investigate the effect of combining L-arginine (Arg) and NaF on the growth of Lactobacillus rhamnosus GG (LRG); and (2) to identify an optimum synergistic concentration for the synbiotic (Arg + LRG)-fluoride (SF) therapy. 1% Arg + 2000-ppm NaF (A-SF) and 2% Arg + 2000-ppm NaF (B-SF) demonstrated antagonism against LRG (FIC > 4.0). Both XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) assays showed that A-SF and B-SF enhanced the growth of LRG when compared to 2000-ppm NaF and LRG control. Colony forming units, bacterial weight, and biofilm thickness of A-SF and B-SF were significantly higher than 2000-ppm NaF and LRG control. Biofilm imaging depicted that 2000-ppm NaF inhibited biofilm formation; while 1%/2% Arg, A-SF, and B-SF increased biofilm growth of LRG. Lactic acid formation was the lowest for 2000-ppm NaF, followed by A-SF and then B-SF. The SF buffer potential after 24 h was the highest for B-SF, and then A-SF. Biofilm pH for B-SF was closest to neutral. Fluoride, Arg and LRG bioavailability remained unaffected in B-SF. The relative gene expression for arcA, argG, and argH was significantly higher for B-SF than the respective controls. In conclusion, combining 2% Arg, 2000-ppm NaF, and LRG provides an optimum synbiotic-fluoride synergism.

scholarly journals Lipoteichoic acid is an important microbe-associated molecular pattern of Lactobacillus rhamnosus GG

2012 ◽  
Vol 11 (1) ◽  
pp. 161 ◽  
Author(s):  
Ingmar JJ Claes ◽  
Marijke E Segers ◽  
Tine LA Verhoeven ◽  
Michiel Dusselier ◽  
Bert F Sels ◽  
...  
Keyword(s):  
Lactobacillus Rhamnosus ◽  
Lipoteichoic Acid ◽  
Lactobacillus Rhamnosus Gg ◽  
Molecular Pattern

scholarly journals Antibiofilm and antivirulence potential of silver nanoparticles against multidrug-resistant Acinetobacter baumannii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helal F. Hetta ◽  
Israa M. S. Al-Kadmy ◽  
Saba Saadoon Khazaal ◽  
Suhad Abbas ◽  
Ahmed Suhail ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Microtiter Plate ◽  
Diffusion Method ◽  
Resistance Pattern ◽  
Infection Model ◽  
The Impact

AbstractWe aimed to isolate Acinetobacter baumannii (A. baumannii) from wound infections, determine their resistance and virulence profile, and assess the impact of Silver nanoparticles (AgNPs) on the bacterial growth, virulence and biofilm-related gene expression. AgNPs were synthesized and characterized using TEM, XRD and FTIR spectroscopy. A. baumannii (n = 200) were isolated and identified. Resistance pattern was determined and virulence genes (afa/draBC, cnf1, cnf2, csgA, cvaC, fimH, fyuA, ibeA, iutA, kpsMT II, PAI, papC, PapG II, III, sfa/focDE and traT) were screened using PCR. Biofilm formation was evaluated using Microtiter plate method. Then, the antimicrobial activity of AgNPs was evaluated by the well-diffusion method, growth kinetics and MIC determination. Inhibition of biofilm formation and the ability to disperse biofilms in exposure to AgNPs were evaluated. The effect of AgNPs on the expression of virulence and biofilm-related genes (bap, OmpA, abaI, csuA/B, A1S_2091, A1S_1510, A1S_0690, A1S_0114) were estimated using QRT-PCR. In vitro infection model for analyzing the antibacterial activity of AgNPs was done using a co-culture infection model of A. baumannii with human fibroblast skin cell line HFF-1 or Vero cell lines. A. baumannii had high level of resistance to antibiotics. Most of the isolates harbored the fimH, afa/draBC, cnf1, csgA and cnf2, and the majority of A. baumannii produced strong biofilms. AgNPs inhibited the growth of A. baumannii efficiently with MIC ranging from 4 to 25 µg/ml. A. baumannii showed a reduced growth rate in the presence of AgNPs. The inhibitory activity and the anti-biofilm activity of AgNPs were more pronounced against the weak biofilm producers. Moreover, AgNPs decreased the expression of kpsMII , afa/draBC,bap, OmpA, and csuA/B genes. The in vitro infection model revealed a significant antibacterial activity of AgNPs against extracellular and intracellular A. baumannii. AgNPs highly interrupted bacterial multiplication and biofilm formation. AgNPs downregulated the transcription level of important virulence and biofilm-related genes. Our findings provide an additional step towards understanding the mechanisms by which sliver nanoparticles interfere with the microbial spread and persistence.

scholarly journals An optimised GAS-pharyngeal cell biofilm model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Heema K. N. Vyas ◽  
Jason D. McArthur ◽  
Martina L. Sanderson-Smith
Keyword(s):  
Crystal Violet ◽  
Biofilm Formation ◽  
Cell Model ◽  
Matrix Material ◽  
Three Dimensional ◽  
Growth Period ◽  
Optimal Growth ◽  
Abiotic Surfaces

AbstractGroup A Streptococcus (GAS) causes 700 million infections and accounts for half a million deaths per year. Biofilm formation has been implicated in both pharyngeal and dermal GAS infections. In vitro, plate-based assays have shown that several GAS M-types form biofilms, and multiple GAS virulence factors have been linked to biofilm formation. Although the contributions of these plate-based studies have been valuable, most have failed to mimic the host environment, with many studies utilising abiotic surfaces. GAS is a human specific pathogen, and colonisation and subsequent biofilm formation is likely facilitated by distinct interactions with host tissue surfaces. As such, a host cell-GAS model has been optimised to support and grow GAS biofilms of a variety of GAS M-types. Improvements and adjustments to the crystal violet biofilm biomass assay have also been tailored to reproducibly detect delicate GAS biofilms. We propose 72 h as an optimal growth period for yielding detectable biofilm biomass. GAS biofilms formed are robust and durable, and can be reproducibly assessed via staining/washing intensive assays such as crystal violet with the aid of methanol fixation prior to staining. Lastly, SEM imaging of GAS biofilms formed by this model revealed GAS cocci chains arranged into three-dimensional aggregated structures with EPS matrix material. Taken together, we outline an efficacious GAS biofilm pharyngeal cell model that can support long-term GAS biofilm formation, with biofilms formed closely resembling those seen in vivo.

Evaluation of the Role of Staphylococci in the Pathomechanism of Conjunctivitis

2021 ◽  
Author(s):  
Ewa Jasińska ◽  
Agnieszka Bogut ◽  
Agnieszka Magryś ◽  
Alina Olender
Keyword(s):  
Antibiotic Resistance ◽  
Epithelial Cells ◽  
Biofilm Formation ◽  
Methicillin Resistance ◽  
Microtiter Plate ◽  
Host Cells ◽  
Diffusion Method ◽  
Microtiter Plate Assay ◽  
Low Prevalence

Abstract Purpose: Determination of the association between ica genes and phenotypic biofilm formation in staphylococcal isolates involved in conjunctivitis, their antibiotic resistance as well as detection of selected virulence characteristics: adhesion to epithelial cells and in vitro cytotoxicity.Methods: The study included 26 Staphylococcus aureus (SA) and 26 Staphylococcus epidermidis (SE) isolates. The presence of icaAD genes and ica operon was determined by the PCR assay. Phenotypic biofilm formation was verified using the microtiter plate assay. Antibiotic resistance was performed using the disc diffusion method. Staphylococcal ability to attach to host cells was assessed by flow cytometry. Cytotoxicity on epithelial cells was evaluated by LDH assay.Results: The ica genes were detected in 26.9% of SE and in 42.3% of SA isolates. Only 15.3% of isolates (SE) were positive for both the icaAD and the ica operon. Phenotypically, 19.2% of SE isolates were strong biofilm producers, among which three were both icaAD- and ica operon-positive. 26.9% of SA isolates were strong biofilm producers. Methicillin resistance (MR) was detected in 34.6% of SE and 26.9% of SA isolates. 75% of MR isolates were multidrug resistant. SA isolates adhered to host cells more extensively than SE. SA isolates released higher level of LDH than SE.Conclusions: Adherence abilities were commonly observed in staphylococci associated with conjunctivitis. However, low prevalence of isolates positive for a complete and functional ica locus and low prevalence of strong biofilm producers was detected. SA adhered to a greater extent to eukaryotic cells than SE and were more cytotoxic.

In Vivo, In Vitro and Transplacental Immune Effects of a Probiotic Bacterium Lactobacillus rhamnosus GG in Humans

2009 ◽  
Vol 123 (2) ◽  
pp. S200-S200
Author(s):  
R.J. Boyle ◽  
L. Mah ◽  
S. Kivivuori ◽  
A. Chen ◽  
S.J. Lahtinen ◽  
...  
Keyword(s):  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Lactobacillus Rhamnosus Gg

scholarly journals Lactobacillus rhamnosus GG and Biochemical Agents Enrich the Shelf Life of Fresh-Cut Bell Pepper (Capsicum annuum L. var. grossum (L.) Sendt)

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1252
Author(s):  
Kandasamy Saravanakumar ◽  
Anbazhagan Sathiyaseelan ◽  
Arokia Vijaya Anand Mariadoss ◽  
Ramachandran Chelliah ◽  
Xiaowen Hu ◽  
...  
Keyword(s):  
Bacterial Colonization ◽  
Antioxidant Properties ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Strain ◽  
Bell Pepper ◽  
Microbial Colonization ◽  
Lactobacillus Rhamnosus Gg ◽  
Combined Application ◽  
Fresh Cut

This work analyzed the individual and combined effects of biochemical additives and probiotic strain Lactobacillus rhamnosus GG on red and yellow fresh-cut bell pepper (R- and Y-FCBP, respectively) stored at two different temperatures (4 °C and 15 °C) for 15 days. The results revealed that the combined application of biochemical additives and L. rhamnosus GG inhibited the colonization of total bacterial counts (25.10%), total Salmonella counts (38.32%), total Listeria counts (23.75%), and total fungal counts (61.90%) in FCBP. Total bacterial colonization was found to be higher in R-FCBP (1188.09 ± 9.25 CFU g−1) than Y-FCBP (863.96 ± 7.21 CFU g−1). The storage at 4 °C was prevented 35.38% of microbial colonization in FCBP. Importantly, the L. rhamnosus GG count remained for up to 12 days. Moreover, the combined inoculation of the biochemical additives and L. rhamnosus GG treatments (T3) maintained the quality of R- and Y-FCBP for up to 12 days at 4 °C without any loss of antioxidant properties. This work reports the successful utilization of L. rhamnosus GG as a preservative agent for maintaining the quality of FCBP by preventing microbial colonization.

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