Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media

Lade, Harshad; Park, Joon Hyun; Chung, Soo Young; Kim, In Hee; Kim, Jungmin; Joo, Hwang-Soo; Kim, Jae‐Seok

doi:10.3390/jcm8111853

Cited by 77 publications

(58 citation statements)

References 62 publications

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“…One of the bacterial strategies of protection from drugs and antibiotics is biofilm formation [ 79 ]. Strains tested in our study, such as S. aureus and P. aureginosa , have the propensity to form biofilms and then the proper antibiotic treatment is much more difficult [ 80 ]. One approach to controlling the production of these might be nanomaterials with antibacterial capabilities [ 81 , 82 ].…”

Section: Resultsmentioning

confidence: 99%

Zinc Oxide Nanocomposites—Extracellular Synthesis, Physicochemical Characterization and Antibacterial Potential

et al. 2020

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This research presents, for the first time, the potential of the Lactobacillus paracasei LC20 isolated from sweet whey as a novel, effective and accessible source for post-cultured ZnO nanocomposites synthesis. The obtained nanocomposites were subjected to comprehensive characterization by a broad spectrum of instrumental techniques. Results of spectroscopic and microscopic analysis confirmed the hexagonal crystalline structure of ZnO in the nanometer size. The dispersion stability of the obtained nanocomposites was determined based on the zeta potential (ZP) measurements—the average ZP value was found to be −29.15 ± 1.05 mV in the 7–9 pH range. The ZnO nanocomposites (NCs) demonstrated thermal stability up to 130 °C based on the results of thermogravimetric TGA/DTG) analysis. The organic deposit on the nanoparticle surface was recorded by spectroscopic analysis in the infrared range (FT-IR). Results of the spectrometric study exhibited nanostructure-assisted laser desorption/ionization effects and also pointed out the presence of organic deposits and, what is more, allowed us to identify the specific amino acids and peptides present on the ZnO NCs surfaces. In this context, mass spectrometry (MS) data confirmed the nano-ZnO formation mechanism. Moreover, fluorescence data showed an increase in fluorescence signal in the presence of nanocomposites designed for potential use as, e.g., biosensors. Despite ZnO NCs’ luminescent properties, they can also act as promising antiseptic agents against clinically relevant pathogens. Therefore, a pilot study on the antibacterial activity of biologically synthesized ZnO NCs was carried out against four strains (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) by using MIC (minimal inhibitory concentration). Additionally, the colony forming units (CFU) assay was performed and quantified for all bacterial cells as the percentage of viable cells in comparison to a control sample (untreated culture) The nanocomposites were effective among three pathogens with MIC values in the range of 86.25–172.5 μg/mL and showed potential as a new type of, e.g., medical path or ointment formulation.

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Section: Resultsmentioning

confidence: 99%

Zinc Oxide Nanocomposites—Extracellular Synthesis, Physicochemical Characterization and Antibacterial Potential

et al. 2020

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“…However, hexadecenoic acid (C16:0), octadecanoic acid (C18:0) and eicosanoic acid (C20:0) could reduce biofilm formation in this study. This might be from the different culture condition including medium, bacterial strain and dose-dependent supplementation of fatty acid (Bravo-Santano et al 2019a;Lade et al 2019;Yoon et al 2018). As a conclusion, this phenomenon might explain how the Δagr mutant strain retained a lower level of fatty acid in the supernatant, since maintaining higher levels of fatty acids would interfere with biofilm formation and increase the instability of the cytoplasmic membrane leading to higher antibiotic susceptibility.…”

Section: Influence Of the Exogenous Addition Of Fatty Acids On Antibimentioning

confidence: 99%

Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism

et al. 2020

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Methicillin-resistant Staphylococcus aureus (MRSA) strains are distinct from general Staphylococcus strains with respect to the composition of the membrane, ability to form a thicker biofilm, and, importantly, ability to modify the target of antibiotics to evade their activity. The agr gene is an accessory global regulator of gram-positive bacteria that governs virulence or resistant mechanisms and therefore an important target for the control of resistant strains. However, the mechanism by which agr impacts resistance to β-lactam antibiotics remains unclear. In the present study, we found the Δagr mutant strain having higher resistance to high concentrations of β-lactam antibiotics such as oxacillin and ampicillin. To determine the influence of variation in the microenvironment of cells between the parental and mutant strains, fatty acid analysis of the supernatant, total lipids, and phospholipid fatty acids were compared. The Δagr mutant strain tended to produce fewer fatty acids and retained lower amounts of C16, C18 fatty acids in the supernatant. Phospholipid analysis showed a dramatic increase in the hydrophobic longer-chain fatty acids in the membrane. To target membrane, we applied several surfactants and found that sorbitan monolaurate (Span20) had a synergistic effect with oxacillin by decreasing biofilm formation and growth. These findings indicate that agr deletion allows for MRSA to resist antibiotics via several changes including constant expression of mecA, fatty acid metabolism, and biofilm thickening.

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Section: Influence Of the Exogenous Addition Of Fatty Acids On Antibimentioning

confidence: 99%

Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism

Song

Choi

Han

et al. 2020

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Methicillin-resistant Staphylococcus aureus (MRSA) strains are distinct from general Staphylococcus strains with respect to the composition of the membrane, ability to form a thicker biofilm, and, importantly, ability to modify the target of antibiotics to evade their activity. The agr gene is an accessory global regulator of gram-positive bacteria that governs virulence or resistant mechanisms and therefore an important target for the control of resistant strains. However, the mechanism by which agr impacts resistance to β-lactam antibiotics remains unclear. In the present study, we found the Δagr mutant strain having higher resistance to high concentrations of b-lactam antibiotics such as oxacillin and ampicillin. To determine the influence of variation in the microenvironment of cells between the parental and mutant strains, fatty acid analysis of the supernatant, total lipids, and phospholipid fatty acids were compared. The Δagr mutant strain tended to produce fewer fatty acids and retained lower amounts of C16, C18 fatty acids in the supernatant. Phospholipid analysis showed a dramatic increase in the hydrophobic longer-chain fatty acids in the membrane. To target membrane, we applied several surfactants and found that sorbitan monolaurate (Span20) had a synergistic effect with oxacillin by decreasing biofilm formation and growth. These findings indicate that agr deletion allows for MRSA to resist antibiotics via several changes including constant expression of mecA, fatty acid metabolism, and biofilm thickening.

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Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media

Cited by 77 publications

References 62 publications

Zinc Oxide Nanocomposites—Extracellular Synthesis, Physicochemical Characterization and Antibacterial Potential

Zinc Oxide Nanocomposites—Extracellular Synthesis, Physicochemical Characterization and Antibacterial Potential

Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism

Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism

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