advances in culture media design (chromogen and inhibigen compounds)
DESCRIPTION
Advances in culture media design (Chromogen and Inhibigen compounds). Neal Parker Industrial account manager. Introduction. Background and principles of Chromogens Why do we use them? Background and principles of Inhibigens Why do we use them?. - PowerPoint PPT PresentationTRANSCRIPT
Advances in culture media design (Chromogen and Inhibigen compounds)
Neal Parker
Industrial account manager
2
Introduction
• Background and principles of Chromogens
• Why do we use them?
• Background and principles of Inhibigens
• Why do we use them?
3
Background and principles of chromogenic media
• Chromogen – “a chemical compound, itself without colour, that can be transformed into a coloured compound, or can react with another material to form a coloured compound”
4
E. coli
Chromophore component (e.g. indoxyl derivative such as 5-bromo-4-chloro-3-indoxyl)
Sugar component (e.g. galactose)
Uptake
Enzyme
Chromogen
Background and principles of chromogenic media
5
Background and principles of chromogenic media
E. coli
6
O
OH
H
H
HO
H
H
OHHO
OH
NH
O
OH
H
H
HO
H
H
OHHOH
OH
HN
NH
O
O
Cl
Br
Cl
Br
Cl
Br
-galactosidase oxidation
5-bromo-4-chloro-3-indoxyl--D-galactopyranoside (X-Gal)
galactose blue-turquoise chromophore
Background and principles of chromogenic media
7
Why use Chromogens?
8
Why use Chromogens?
• Improve overall specificity of a diagnostic medium.
• Positive colonies are easy to identify.
• Reduce number of sub-cultures required.
9
Current chromogen situation
• The large scale synthesis of chromogens means compounds are affordable for use in culture media
• There are now chromogenic media available for almost all organisms of interest in both the Industrial and Clinical environments
• >30 chromogenic media formulations are currently available for the differentiation of E. coli and coliforms
• >10 formulations for Salmonella
10
From chromogens to inhibigens…
11
Background and principles of Inhibigens
• Inhibigen – “an inhibitor molecule linked to a specific substrate. In this bound state, the inhibitor is non-toxic. However, if taken up by a cell and cleaved from the substrate, the Inhibigen molecule will prevent the organism from replicating ”
12
Uptake
Inhibition of cell wall synthesis
Loss of viability
Inhibitor component (AEP)
Sugar or amino acid component
InhibigenTM
Specific enzyme hydrolysis
-
XFree inhibitor in medium is not actively taken up
Background and principles of Inhibigens
13
• XLD • Brilliance Salmonella (InhibigenTM)
Why use Inhibigens?
14
Why use Inhibigens?
• Reduce stress on target organism
• Improve sensitivity
• Reduce growth of non-target organisms
15
Current Inhibigen Situation
• Inhibigens are a patented concept• Small scale manufacture • Currently only one product containing Inhibigen compounds
• Many more are in the pipeline