1.Colony morphology. The shape, texture and color of bacterial colonies can be distinctive. For example, Staphylococcus aureus is so named as colonies are of a yellow color; aureuscomes from the Latin for golden
The shape, texture and color of bacterial colonies can be distinctive. For example, Staphylococcus aureus is so named as colonies are of a yellow color; 'aureus' comes from the Latin for golden. 1.Colony morphology
Whether bacteria are gram-positive or gram-negative is one of the most im portant clinical diagnostic tests. Gram staining and microscopic examination of bacteria give information as to the shape, size and arrangement of the bacterial cells and in some cases this is enough to identify certain genera such as Streptococci which are Gram-positive cocci that grow in chains Stains may also be used to show other morphological features which may be used for classification, such as the presence of spores(malachite green stain); unusual cell walls(Ziehl Neelsen acid-fast stain) capsules(Indian ink stain); intracellular lipids Sudan black); flagella (flagellarstain) metachromatic granules (Albert-Ley bourne stain) 2. Cell shape, structures and reaction to stains
Whether bacteria are Gram-positive or Gram-negative is one of the most important clinical diagnostic tests. Gram staining and microscopic examination of bacteria give information as to the shape, size and arrangement of the bacterial cells and in some cases this is enough to identify certain genera such as Streptococci which are Gram-positive cocci that grow in chains. Stains may also be used to show other morphological features , which may be used for classification, such as the presence of: spores (malachite green stain); unusual cell walls (Ziehl Neelsen acid-fast stain); capsules (Indian ink stain); intracellular lipids (Sudan black); flagella (flagellar stain); metachromatic granules (Albert-Leybourne stain). 2.Cell shape, structures and reaction to stains
3. Growth characteristics The temperature, pH and 0 requirements of an isolate are useful tests for the identification of bacteria
The temperature, pH and 0; requirements of an isolate are useful tests for the identification of bacteria. 3.Growth characteristics
There is a wide range of tests available that measure various aspects of bacterial metabolism what carbon and nitrogen sources the bacteria can use the end products of their metabolic processes, such as acetoin tested for in the vogues-Proskaeur test what enzymes the bacteria produce, such as decarboxylases, proteases and DNases; the presence of other molecules such as toxins lori- chain fatty acids or anti biotics Biochemical tests
There is a wide range of tests available that measure various aspects of bacterial metabolism: • what carbon and nitrogen sources the bacteria can use; • the end products of their metabolic processes, such as acetoin, tested for in the Vogues-Proskaeur test; • what enzymes the bacteria produce, such as decarboxylases, proteases and DNases; • the presence of other molecules such as toxins , long- chain fatty acids or antibiotics. Biochemical tests
Antibodies to cellular components such as the O-side chains of lipopolysaccharide(LPS) (Topic D3 )or capsules are frequently used to distinguish between strains of one species Immunological tests
Antibodies to cellular components such as the 0-side chains of lipopolysaccharide (LPS) (Topic D3) or capsules are frequently used to distinguish between strains of one species. Immunological tests