Broth dilution assay

This compound was then assessed in a broth-dilution assay and found to have an MIC of 31.2 pg/mL. 

Compound Bioautography Agar Well Diffusion Assay Serial Broth Dilution Assay Alamar Blue Assay ... 

Schematic illustration showing the setup of the broth dilution assay.

Broth dilution assay and agar plate assay done on M. avium to determine MIC and MBC values for antituberculosis drugs (a, e) clarithromycin, (b, f) streptomycin, (c, g) isoniazid, and (d. h) pyrazinamide. 

Table 3 Minimal Inhibitory Concentrations of LY303366 and Amphotericin B that Inhibited 50% (MIC ) and 90% (MlC g) of 107 Clinical Isolates of C. albic

Since it has been observed by the authors that modifications of the Rammelkamp broth dilution method for assay (28) enjoy the greatest popularity in laboratories today, a composite of these modifications, as used with satisfaction in the authors laboratory, is presented here. Practically all assay procedures for antibiotics discovered after penicillin are patterned on the penicillin assay itself. Therefore it serves our purpose to outline the assay for newer agents by indication of changes or substitutions which must be made in the basic (penicillin) method. 

Filter paper activity, which describes the overall cellulolytic activity of an enzyme preparation, was determined by the method of Mandels et al. (16). A 1 x 6 cm strip of Whatman no.l filter paper (Hillsboro, OR), which equals 50 mg of cellulose, served as the substrate and was added to the sample solution containing 0.5 mL of appropriate diluted enzyme (supernatant of culture broth) and 1.0 mL of 0.05 M citrate buffer (pH 4.8). After 60 min of incubation at 50°C, the hydrolysis was terminated by the addition of 3 mL of DNS solution, and the mixture was further assayed for reducing sugar content by the DNS method. One international filter paper unit (FPU) was defined as the amount of enzyme that releases 1 pmol of glucose/min under the assay conditions. Activities were reported as FPU/milliliter. 

The medium is adjusted to pH 7.0 prior to sterilization for 20 minutes at 121°C. The fermentation flasks are incubated and agitated under similar conditions as the germination flasks. After 72 hours the mycelium was separated by centrifugation and the untreated broth assayed by the streak dilution method. 30 liters of broth are centrifuged and 6% of Darco G-60 charcoal is added to the clear solution, which is stirred for 30 minutes then the charcoal is filtered off to give an almost colorless solution which is concentrated in vacuum at 45-50°C to 1.5 liters. The concentrated solution is poured under stirring into 5 liters of methanol, the formed precipitate is... 

Add 50 pL of a log-phase bacterial suspension, diluted to approximately 1.5 x 106 cells/mL, in a microfuge tube and then add 100-x pL of liquid medium (e.g., MH broth), where x corresponds to the volume of peptide to be assayed (x = 0 in the control tubes). Use the PRP at a bactericidal concentration for the parental wild-type strain (HB101). Different PRP peptide concentrations may be used (e.g. 5X MIC). 

Overnight culture of S. aureus was diluted 100-fold in fresh MH II Broth and used as inoculums for the antimicrobial screen. Working stocks (SOX) of LOPAC compounds and standard antibiotics were prepared in DMSO. Each well of the 96-well multiwell plate contained 245 pL of the inoculums and 5 pL of the 50X working stock. The multiwell plate was incubated at 37°C for 5 h. Culture samples were taken from each well and the BacTiter-Glo Assay was performed. The samples and concentrations are Wells 1-4 and 93-96, negative control of 2% DMSO, wells... 

These bacteria were cultivated in each product for 24 h at 37 °C and each cultured broth sample was serially diluted into the corresponding aseptic products. The total colony count was determined with Plate Count Agar (MERCK). Bioluminescent Assay... 

In order to determine nitrofuran activity in vitro, the minimum inhibitory concentration (MIC) in bacterial cultures must be found by using the serial two fold dilution technique with broth as a medium. Incubation time is 24 hours at 37°C. The cup method, which is usually employed for the assay... 

---