Dental Caries
Written by Dr.ChrisDental Caries: Caries means the destruction of enamel, dentin or cementum is clearly caused by bacteria. It is the microbial plaque which represents a large mass of metabolically active bacteria capable of initiating dental caries (cavities), peridontal disease or both. The gnotobiotic rats (rats free of bacteria) fail to develop dental caries even when the […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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Microbiology of Oral Cavity
Written by Dr.ChrisMicrobiology of Oral Cavity: It is beyond doubt that majority of widespread dental diseases are caused by bacteria. The oral cavity has a number of surfaces & crypts for colonization of micro-organisms. However microbial growth is slow. Still large, dense populations of micro-organisms can accumulate on tooth surfaces (dental plaques), on dorsum of tongue, in […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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MICROCOCCUS TETRAGEN
Written by Dr.ChrisMICROCOCCUS TETRAGEN (GAFFKYA TETRAGENA): It is a commensal of mucosa of upper respiratory tract. It is Gram positive cocci slightly longer than staphylococci and occur in tetrad. It is capsulated when in tissue.
Cultural Character:
Fluid media: In broth a thick deposit may develop. Supernatant fluid may remain clear.
Nutrient agar: The colony is white. It is emulsified […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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SCHWARTZMAN REACTION
Written by Dr.ChrisSCHWARTZMAN REACTION: This is not an immune reaction but rather an alteration in factors affecting intravascular coagulation.
Culture filtrate of Salmonella typhi if injected intradermally in a rabbit followed 24 hours later by same filtrate intravenously, a hemorrhagic necrotic lesion develops at the site of intradermal injec-tion. The intradermal and intravenous injections need not be of […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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Techniques of Precipitation Reaction
Written by Dr.ChrisTechniques of Precipitation Reaction:
(1) Ring test: The test is very simple for detection of antigen. The antigen is layered over serum in a narrow tube. The reaction is visible as a white zone at the junction of two clear fluid. Examples are C-reactive protein test, Ascoli test, grouping of streptococci by Lancefield technique.
(2) Slide test: When a […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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Types of Testing Bacteria
Written by Dr.ChrisTypes of Testing Bacteria: The more important and widely used tests are as under:
1. Sugar fermentation: This is tested in sugar media having Andrade’s indicator. Acid production changes the color of medium into pink. Gas produced collects in Durham’s tube.
2. Indole production: This test demonstrates production of indole from tryptophane. This tryptophane is present in peptone water. […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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METHODS OF ANAEROBIC CULTURE
Written by Dr.ChrisMETHODS OF ANAEROBIC CULTURE: Obligate anerobes grow only in absence of free oxygen. These bacteria lack mechanism of oxidation through respiratory enzymes like cytochrome oxidase, catalase and peroxidase resulting in H202 accumulation. This H2O, is toxic for the growth of anaerobic bacteria.
Clostridium tetani are strictly anaerobic. A number of methods are described for achieving anaerobiosis […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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Methods of Culture of Bacteria
Written by Dr.ChrisMethods of Culture:
(1) Streak culture (surface plating) is the method routinely employed for the isolation of bacteria in pure culture. A platinum loop with 2J/2″ long wire and loop with diameter 2 mm is charged with specimen to be cultured and is placed on the surface of dried plate of solid media towards peripheral area. The […]
Tags: B. subtilus, friable, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus hemolyticus
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Tuberculosis of Skin
Written by D C MorganMycobacterium tuberculosis may cause skin lesions in varied forms depending on the cell mediated immunity of the patient. If a new born or a patient with no CMI against M tuberculosis is infected for the first time,it results in the development of a chancriform ulcer on the skin. The regional lymph node soon gets involved […]
Tags: Antituberculous Drugs, CMI, Erythema Induratum, Lupus Vulgaris, Mantoux Test, Mycobacterium tuberculosis, Papulonecrotic Tuberculids, Tubercle bacilli
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