antimicrobial efficacy against staphylococcus aureus atcc 6538 exemplary use rate  (ATCC)

Journal: Biofilm

Article Title: Octanoic acid promotes clearance of antibiotic-tolerant cells and eradicates biofilms of Staphylococcus aureus isolated from recurrent bovine mastitis

doi: 10.1016/j.bioflm.2023.100149

Figure Lengend Snippet: Antibacterial activity of octanoic acid and antibiotics tested on bovine mastitis pathogens. Antibiotic susceptibility testing in (A) Staphylococcus spp., (B) Streptococcus spp., (C) Escherichia coli , and other pathogens isolated from dairy cows with mastitis. (D) Octanoic acid antimicrobial efficacy against S. aureus ATCC 12600 and clinical isolates of MCPs. MICs and MBCs of octanoic acid and antibiotics tested on S. aureus ATCC 12600 and clinical isolates of MCPs. The MBCs in milk were also determined in this study. All values represent the mean ± SD of three individual experiments. Determination of susceptibility of strains to antibiotics followed CLSI guidelines, with minor modifications. Susceptibility is defined by a MIC of ≤4 μg/mL and a MIC of ≥16 μg/mL was considered resistant.

Article Snippet: Antibiotic susceptibility testing in (A) Staphylococcus spp., (B) Streptococcus spp., (C) Escherichia coli , and other pathogens isolated from dairy cows with mastitis. (D) Octanoic acid antimicrobial efficacy against S. aureus ATCC 12600 and clinical isolates of MCPs.

Techniques: Activity Assay, Isolation

Journal: Biofilm

Article Title: Octanoic acid promotes clearance of antibiotic-tolerant cells and eradicates biofilms of Staphylococcus aureus isolated from recurrent bovine mastitis

doi: 10.1016/j.bioflm.2023.100149

Figure Lengend Snippet: Antibacterial effects of octanoic acid and antibiotic combinations against bovine mastitis pathogen S. aureus . Checkerboard analyses showing percentage inhibition for the combined effects of octanoic acid with ampicillin, cloxacillin, cefuroxime, cefotaxime and tetracycline toward (A) S. aureus ATCC 12600 and (B) clinical isolate 10-9. The heat map shows the average of three replicates. The positions of the blue values represent the concentrations calculated by FICI. (F) The FICI results and definitions of octanoic acid and antibiotic combinations. FICI ≤ 0.5 indicates synergism, while FICI >0.5–1 indicates an additive effect. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Antibiotic susceptibility testing in (A) Staphylococcus spp., (B) Streptococcus spp., (C) Escherichia coli , and other pathogens isolated from dairy cows with mastitis. (D) Octanoic acid antimicrobial efficacy against S. aureus ATCC 12600 and clinical isolates of MCPs.

Techniques: Inhibition

Journal: Biofilm

Article Title: Octanoic acid promotes clearance of antibiotic-tolerant cells and eradicates biofilms of Staphylococcus aureus isolated from recurrent bovine mastitis

doi: 10.1016/j.bioflm.2023.100149

Figure Lengend Snippet: Evaluation of biofilm formation inhibition activity of octanoic acid in the recurrence of mastitis major pathogens S. aureus . (A) A photograph of S. aureus ATCC 12600 and clinical isolates of Staphylococcus sp. biofilms stained with crystal violet (upper) and biofilm biomass quantification (lower). Highlighted (yellow) clinical isolates 7-2, 7-3, 10-9, 11-1, and 12-12 are strains with strong biofilm-forming capacity in milk. Biofilms formed by S. aureus ATCC 12600 and clinical isolates 7-2, 7-3, 10-9, 11-1, and 12-12 were tested with octanoic acid (0–25 mM) in sBHI (B) and milk (C). After a 24 h incubation at 37 °C, biofilms were stained with crystal violet for quantification of bacterial biomass. Untreated control was taken as 100% biofilm formation. The dotted line represents 50% biofilm inhibition. All values represent the mean ± SD of three individual experiments. * p < 0.05 compared with the untreated. (D) SEM images at 12000 × magnification in S. aureus ATCC 12600 biofilm formation treatment by octanoic acid (untreated, 6.25 and 12.5 mM). Yellow arrows represent the extracellular matrix of the S. aureus biofilm. Scale bars = 10 μm. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Antibiotic susceptibility testing in (A) Staphylococcus spp., (B) Streptococcus spp., (C) Escherichia coli , and other pathogens isolated from dairy cows with mastitis. (D) Octanoic acid antimicrobial efficacy against S. aureus ATCC 12600 and clinical isolates of MCPs.

Techniques: Inhibition, Activity Assay, Staining, Incubation

Journal: Biofilm

Article Title: Octanoic acid promotes clearance of antibiotic-tolerant cells and eradicates biofilms of Staphylococcus aureus isolated from recurrent bovine mastitis

doi: 10.1016/j.bioflm.2023.100149

Figure Lengend Snippet: Evaluation of octanoic acid and antibiotics in S. aureus biofilm eradication assay. (A) S. aureus ATCC 12600 mature biofilm treated with antibiotics (0–400 μg/mL), (B) commercial intramammary antibiotics (diluted 1:8 to 1:256 in sBHI), and (C) octanoic acid (0–100 mM) for 24 h. Biofilm cell viability was quantified by Alamar Blue assay. Untreated control was taken as 100% cell viability. The dotted line represents 95% biofilm eradication. Octanoic acid and antibiotic 95% biofilm eradication concentration (95% BEC) and 95% BEC/MBC are listed in table (D). All values represent the mean ± SD of three individual experiments. * p < 0.05 compared with the untreated control. (E) SEM images at 30,000 × magnification in ATCC 12600 S. aureus mature biofilm treatment by octanoic acid (untreated, 25 and 50 mM). Yellow arrows represent the ECM of S. aureus mature biofilm. Yellow thin arrows represent collapsed cells in octanoic acid-treated biofilms. Scale bars = 4 μm. (F) ATCC 12600 S. aureus mature biofilm cell viabilities were analyzed after culture in sBHI (Untreated), 50 mM octanoic acid, or 0.4 mg/mL antibiotics by CLSM at 20 × magnification. BacLight LIVE/DEAD viability kit was used to stain biofilm cells. Bacteria with intact cell membranes were stained fluorescent green (SYTO™ 9), while bacteria with damaged membranes were stained fluorescent red (propidium iodide). CLSM imaging shows green and red fluorescence (upper), representing the total cell content in biofilms, and red fluorescence alone (lower), representing the content of dead cells in biofilms. Lateral white scale bars = 20 μm. Longitudinal white scale bar = 15 μm. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Antibiotic susceptibility testing in (A) Staphylococcus spp., (B) Streptococcus spp., (C) Escherichia coli , and other pathogens isolated from dairy cows with mastitis. (D) Octanoic acid antimicrobial efficacy against S. aureus ATCC 12600 and clinical isolates of MCPs.

Techniques: Alamar Blue Assay, Concentration Assay, Staining, Imaging, Fluorescence

Journal: Biofilm

Article Title: Octanoic acid promotes clearance of antibiotic-tolerant cells and eradicates biofilms of Staphylococcus aureus isolated from recurrent bovine mastitis

doi: 10.1016/j.bioflm.2023.100149

Figure Lengend Snippet: Comparative time-kill curves of octanoic acid and antibiotics against S. aureus cells at planktonic stage, biofilm stage, or biofilms after antibiotic (tetracycline or cloxacillin) exposure. (A) Schematic diagram of the experimental design. Representative time-kill curves for S. aureus ATCC 12600 and isolate 10-9 after exposure to octanoic acid at 2 × MBC (100 mM) and antibiotics at 4 × MBC (ampicillin, cloxacillin, cefuroxime and cefotaxime were respectively treated at 3.125, 1.56, 12.5, and 12.5 μg/mL for S. aureus ATCC 12600 and 1.56, 0.39, 3.13, and 6.25 μg/mL for S. aureus 10-9). S. aureus cells collected from the planktonic stage (B), biofilm stage (C), or biofilms after tetracycline (D) or cloxacillin (E) exposure. CFU/mL of each group was calculated at 0, 4, 8, and 24 h. The dotted line represents the minimum duration to kill 99% of the population (MDK99). The solid line represents the minimum duration to kill 99.99% of the population (MDK99.99). All values represent the mean ± SD of three individual experiments.

Article Snippet: Antibiotic susceptibility testing in (A) Staphylococcus spp., (B) Streptococcus spp., (C) Escherichia coli , and other pathogens isolated from dairy cows with mastitis. (D) Octanoic acid antimicrobial efficacy against S. aureus ATCC 12600 and clinical isolates of MCPs.

Techniques: