mic daptomycin concentration  (ATCC)

Journal: Microbiology Spectrum

Article Title: In vitro persistence of clinical methicillin-resistant Staphylococcus aureus isolates from bone and joint infections after exposure to daptomycin, telavancin, and vancomycin

doi: 10.1128/spectrum.01576-25

Figure Lengend Snippet: Twenty-four-hour survival curves of six MRSA isolates and one MSSA isolate (STA 29213) at mid-exponential phase treated with steady-state concentrations of telavancin (TLV), daptomycin (DAP), or vancomycin (VAN). Each time point represents the mean values of the two replicates with standard deviations.

Article Snippet: Since both 1× and 2× the MIC were able to complete the three passes, the 2× MIC daptomycin concentration was used to provide the highest test concentration that still provided bacterial load to continue the passes over 72 h. The time course of persister development for the six MRSA isolates in addition to the ATCC strain after daptomycin pre-exposure to daptomycin, telavancin, or vancomycin as percent of bacterial burden relative to the respective control time point after 3 days of daptomycin exposure is shown in .

Techniques:

Journal: Microbiology Spectrum

Article Title: In vitro persistence of clinical methicillin-resistant Staphylococcus aureus isolates from bone and joint infections after exposure to daptomycin, telavancin, and vancomycin

doi: 10.1128/spectrum.01576-25

Figure Lengend Snippet: Twenty-four-hour survival curves of six MRSA isolates and one MSSA isolate (STA 29213) at mid-exponential phase after three serial passes of daptomycin (two times MIC) exposure and then treatment with steady-state concentrations of telavancin (TLV), daptomycin (DAP), or vancomycin (VAN). Each time point represents the mean values of the two replicates with standard deviations. The results were capped at 100%.

Article Snippet: Since both 1× and 2× the MIC were able to complete the three passes, the 2× MIC daptomycin concentration was used to provide the highest test concentration that still provided bacterial load to continue the passes over 72 h. The time course of persister development for the six MRSA isolates in addition to the ATCC strain after daptomycin pre-exposure to daptomycin, telavancin, or vancomycin as percent of bacterial burden relative to the respective control time point after 3 days of daptomycin exposure is shown in .

Techniques:

Journal: bioRxiv

Article Title: Enterococcus faecalis and pathogenic streptococci inactivate daptomycin by releasing phospholipids

doi: 10.1101/149971

Figure Lengend Snippet: Streptococci and enterococci release phospholipid and inactivate daptomycin. (a-h), percentage survival of bacteria after 8 h incubation in broth containing the indicated concentrations of daptomycin. (i-p) the concentration of phospholipid in culture supernatants of bacteria exposed to daptomycin as determined by reactivity with a fluorescent dye (RFU: relative fluorescence units). Note the different Y-axis scale for staphylococci vs other bacteria. (q-x) relative percentage of daptomycin activity remaining in culture supernatants of bacteria exposed to daptomycin for 8 h. The activity of daptomycin incubated in culture medium only for 8 h was taken to be 100 %. For all data, the mean of 4 independent experiments are shown, and error bars represent the standard deviation of the mean.

Article Snippet: We initially determined the daptomycin minimum inhibitory concentration (MIC) for a representative panel of Gram-positive pathogens: S. aureus SH1000 [ ], S. epidermidis ATCC 12228 [ ], GAS strain A40 [ ]; GBS strains 515 [ ] and COH1 [ ]; S. gordonii strain Challis [ ]; and E. faecalis strains JH2-2 [ ] and OG1X [ ].

Techniques: Bacteria, Incubation, Concentration Assay, Fluorescence, Activity Assay, Standard Deviation

Journal: bioRxiv

Article Title: Enterococcus faecalis and pathogenic streptococci inactivate daptomycin by releasing phospholipids

doi: 10.1101/149971

Figure Lengend Snippet: De novo lipid biosynthesis is required for enterococcal inactivation of daptomycin. Phospholipid concentration (RFU) in culture supernatants from S. aureus (a) or E. faecalis OG1X (b) incubated for 8 h in media containing daptomycin (10 µg ml -1 ) only (dap) or both daptomycin and 0.5 X MIC platensimicin (dap + pla). (c,d) relative % daptomycin activity in supernatants from cultures described in (a) and (b), respectively. Data in (a) and (b) were analysed using a one-way ANOVA with Tukey’s post-hoc test. Data in (c) and (d) were analysed by a Student’s t -test. *P=<0.05.

Article Snippet: We initially determined the daptomycin minimum inhibitory concentration (MIC) for a representative panel of Gram-positive pathogens: S. aureus SH1000 [ ], S. epidermidis ATCC 12228 [ ], GAS strain A40 [ ]; GBS strains 515 [ ] and COH1 [ ]; S. gordonii strain Challis [ ]; and E. faecalis strains JH2-2 [ ] and OG1X [ ].

Techniques: Concentration Assay, Incubation, Activity Assay

Journal: bioRxiv

Article Title: Enterococcus faecalis and pathogenic streptococci inactivate daptomycin by releasing phospholipids

doi: 10.1101/149971

Figure Lengend Snippet: Loss of daptomycin activity in supernatant is not due to antibiotic binding to bacteria. (a) percentage survival of E. faecalis OG1X incubated with various concentrations of daptomycin (dapt) or Bodipy-daptomycin (Bodipy-dapt) for 8 h. (b) relative percentage daptomycin activity in culture supernatants described in (a). (c) binding of Bodipy-daptomycin to S. aureus or E. faecalis OG1X after 8 h incubation in media containing the indicated concentration of the labelled antibiotic. (d) quantification of Bodipy-daptomycin (RFU) remaining in culture supernatants from S. aureus or E. faecalis OG1X, after 8 h incubation with Bodipy-daptomycin as described in (c) * indicates significantly different from 0 h time point. (e) relative percentage activity of daptomycin (5 μg ml -1 ) activity in TSB only (TSB + dapt), in the supernatant from E. faecalis incubated with daptomycin for 8 h (s/n) and after the addition of 5 μg ml -1 daptomycin to the supernatant from E. faecalis incubated with daptomycin for 8 h (s/n + dapt). Data in (d) and (e) were analysed by a two-way ANOVA with Tukey’s post-hoc test. Graphs show the mean average and, where shown, error bars represent the standard deviation of the mean. For each panel *P=<0.05.

Article Snippet: We initially determined the daptomycin minimum inhibitory concentration (MIC) for a representative panel of Gram-positive pathogens: S. aureus SH1000 [ ], S. epidermidis ATCC 12228 [ ], GAS strain A40 [ ]; GBS strains 515 [ ] and COH1 [ ]; S. gordonii strain Challis [ ]; and E. faecalis strains JH2-2 [ ] and OG1X [ ].

Techniques: Activity Assay, Binding Assay, Bacteria, Incubation, Concentration Assay, Standard Deviation