Medical microbiology is a branch of science that deals with the study of of pathogenic micro-organisms and is concern with disease, diagnosis ,prevention, control and treatment.
Diseases caused by micro-organisms
- Staphylococcus aureus
- Staphylococcus aureus are gram-positive spherical cocci approximately 1 micrometer in diameter.These cells may be arranged in singly,in pairs,shorts chains or in clusters.
- They are non-spore forming, non-motile.They may be capsulated or non-capsulated.
- Under influence of some chemicals the cocci form may change into L-forms.
2. Cultural characters
- Staphylococcus aureus may readily grow in ordinary media.It can grow on Nutrient agar, MacConkey’s agar.
- It grow on temperature range of 10° C to 42° C and optimum temperature for its growth is 37° C
- Optimum pH is 7.3-7.6.
- They may be aerobic or facultative anaerobic in nature.
- The colonies are 2-4 mm in diameter,circular in shapes ,convex and shiny .
- These organisms are golden yellow pigment producing organism.These pigment production occurs in aerobic cultures at optimum pH at 22°C.
- Most of the strains of Staphylococcus aureus show heamolytic activity on blood agar.
- The Staphylococcus aureus show pink coloured colony due to lactose fermentation on MacConkey’s agar.