Microbial Assays for Antibiotics Package

The Microbial Assays for Antibiotics Package covers potency estimation of cylinder-plate assays and turbidimetric assays as described in the U.S. Pharmacopeia <81> and Japanese Pharmacopoeia Chapter 4.02. It also allows to group samples and aggregate samples of independent assay runs to calculate combined potencies. For cylinder-plate assays, inter-plate variation correction methods are provided as recommended in USP <81>. Moreover, logarithmic dose transformation and response data processing can be applied. The customizable documentation section includes additional information for documentary purposes such as antibiotic description, inoculum preparation, and assay setup. Finally, the validity of the assay can be proven in configurable tests on the calculated parameters.

pic.1 - Combined potency estimation of five cylinder-plate assays (Combination group 1)
pic.2 - Combined potency estimation of five cylinder-plate assays (Combination group 2)
pic.3 - Concentration estimation of a Test sample in a cylinder-plate assay as recommended by JP chapter 4.02
pic.4 - Concentration estimation of three Test samples in a cylinder-plate assay as recommended by USP <81>. (Large) inter- and intra-plate effects are corrected by the correction point method
pic.5 - Concentration estimation of three Test samples in a cylinder-plate assay as recommended by USP <81>. (Small) inter- and intra-plate effects are corrected by the correction point method
pic.6 - Concentration estimation of a Test sample in a cylinder-plate assay as recommended by USP <81>

pic.7 - Concentration estimation of a Test sample in a turbidimetric assay as recommended by JP chapter 4.02
pic.8 - Concentration estimation of a Test sample (light blue) in a turbidimetric assay as recommended by USP <81>. In addition, a Control sample (purple) was submitted to the assay

 

Features

  • Calculate potencies based on the cylinder-plate and turbidimetric method.
  • Perform the assays by following the U.S. Pharmacopeia <81> or the Japanese Pharmacopoeia Chapter 4.02.
  • Document the entire procedure of inoculum preparation and assay setup.
  • Configure dose transformation and response data processing.
  • Set up combination groups to estimate the combined potency within a group of samples.
  • Define a test system to account for the calculated variables.

Basic concept

The Microbial Assays for Antibiotics Package provides you with document types for the cylinder-plate and turbidimetric method to estimate the potency of your test samples following either the U.S. Pharmacopeia (USP) <81> or the Japanese Pharmacopoeia (JP) Chapter 4.02. You can aggregate independent assay runs into the combination of microbial assays document for combined potency calculation. For documentary purposes, you can enter information about the antibiotic, inoculum preparation, and assay setup into the documentation section of the individual assay documents. Moreover, prove the validity of the assay in your test system by accounting for parameters such as the correction point (USP <81>) or the potency factor A (JP Chapter 4.02).


Use cases

The Microbial Assays for Antibiotics Package follows the guidances of the U.S. Pharmacopeia (USP) <81> and Japanese Pharmacopoeia (JP) Chapter 4.02 in separate document types to estimate the potency of cylinder-plate and turbidimetric assays.* It supports you during preparation of the assay by providing customizable documentation options regarding the antibiotic and the inoculum. For instance, information about the incubation, the base and seed layer medium, the equipment, the operator, and the purpose can be recorded. In addition, when performing a cylinder-plate assay as described in the USP <81>, you can apply plate-to-plate variation correction choosing between the correction point method and estimations from the regression line. Next, you can define test systems to prove the validity of your assay. Finally, the results provide you with potency estimations for your test samples including overall test results. Once you have collected data from multiple assay runs, aggregate the independent documents to perform combined potency calculations for each combination group of test samples.

*Set up microbial assays for antibiotics according to regulations by the European Pharmacopoeia with Quantitative response assay documents from the Biological Assay Package.


Example

  • Sample Report for a combination of microbial assays 23 KB
    Example combination of microbial assay documents. Cylinder-plate assays (based on USP <81>) are aggregated to determine the combined potency. In addition, test samples from the original assay documents are put into combination group 1 and 2 respectively. This results in a separate analysis for each group. The test system includes tests on the combined potency, the confidence interval of the estimated combined potency, and the CV (%) of the absolute potency values.
  • Sample Report for a cylinder-plate assay as recommended by JP chapter 4.02 32 KB
    Example cylinder-plate assay based on JP 4.02: Erythromycin is used as antibiotic substance on the test organism Staphylococcus aureus. The standard and the test sample consist of a high and a low concentration step. The standard sample is used as reference to determine the relative potency of the test sample TST1. The test system includes tests on the relative response standard deviation (high and low concentration) and the potency factor A.
  • Sample Report for a cylinder-plate assay as recommended by USP <81> 49 KB
    Example cylinder-plate assay based on USP <81>: Cloxacillin is used as antibiotic substance on the test organism Staphylococcus aureus. The standard consists of five concentration steps (S1 to S5) with S3 being used as reference. The relative potency of the unkown sample U3 is estimated based on the standard. In accordance with USP <81>, the test system includes tests on the relative standard deviation CV (%), the coefficient of determination (r^2), and the relative potency. For a direct comparison, the response values are taken from USP <81>. Moreover, the concentration is log10-transformed as recommended by USP <81>.
  • Sample Report for a turbidimetric assay as recommended by JP chapter 4.02 47 KB
    Example turbidimetric assay based on JP 4.02: Gramicidin is used as antibiotic substance on the test organism Enterococcus hirae. The standard consists of five concentration steps (S1 to S5) with S3 being used as reference. The relative potency of the unkown sample TST1 is estimated based on the standard. The test system includes tests on the combined standard deviation of the standard, the coefficient of determination (r^2), and the relative potency.
  • Sample Report for a turbidimetric assay as recommended by USP <81> 54 KB
    Example turbidimetric assay based on USP <81>: Capreomycin is used as antibiotic substance on the test organism Klebsiella pneumoniae. The standard consists of five concentration steps (S1 to S5) with S3 being used as reference. The relative potency of the unkown sample U3 is estimated based on the standard. The control sample CTL1 contains the test diluent but no antibiotic. Note that the interpolated concentration value of CTL1 is beyond the regression line and therefore does not allow any conclusion about the true estimate (e.g. nonlinear trend for high response values). In accordance with USP <81>, the test system includes tests on the combined standard deviation of the standard, the coefficient of determination (r^2), and the relative potency. For a direct comparison, the response values are taken from USP <81>. Moreover, the concentration is log10-transformed as recommended by USP <81>.