46
2. Mueller Hinton Agar : Preparation / Composition
Preparation :
• Suspend the components, dried powder, in water (38 grams in 1000 ml
of purified/distilled water). The medium is boiled for a few seconds until
the ingredients are completely dissolved. Autoclave to 15 lb (121°C) for
15 minutes. 15g of the powder has been used for the procedure.
• Cool to 45-50°C, mix well before pouring into sterile Petri dishes.
• Divide the medium into sterile petri dishes to obtain a thickness of 4 mm
0.5 mm (approximately 25 mL per 90 mm diameter petri dish), Allow the
agar to set before moving the boxes. (Eucast 2020).
3. Microorganisms
A total of four microorganisms, comprising of two types of gram-negative bacteria, one types
of gram-positive bacteria, and one fungus, were subjected to testing for the antibacterial effects
of chitosan.
Table 12 : Basic features of bacterial strains used in the current study
Microbialstrain
Gram
strain
ATCC
Escherichia coli
Gram -
8739
Staphylococcus aureus
Gram +
6538
Pseudomonas aeruginosa
Gram -
8626
Candida albicans
Yeast
10231
The strains were provided by Group Saidal Dar El-baida, Microbiology Department.
Figure 37 : MullerHinton culture medium