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Bacteria special tests Bacteria special tests are useful characteristic tests for presumptive identification of various bacteria as shown below. Hanging drop preparation-motility test:  It is the most common test of bacteria to check whether organism motile non-motile ( having flagella or not). If the bacteria are motile, notice for the type of motility e.g. darting motility for Vibrio cholerae and Helicobacter pylori, tumbling motility for Listeria monocytogenes, stately motility for Clostridium, Spinning motility for Fusobacterium gyrans, and gliding motility...

Two indicators media Outlines of the topic two indicators media are introduction and use. Medium carrying two indicators are the most common question asking in the examination as viva, therefore today we concern with those media as shown below. Two indicators medium are: 1. Hekton enteric agar It contains two indicators a)acid fuchsin and b) bromothymol blue. Introduction:  Hektoen enteric agar(HEA) is named after the Hektoen Institute in Chicago, where researchers developed the agar. It is a...

Diagnostic antimicrobial agents(Antibiotics) There are some diagnostic antimicrobial agents that are used for the presumptive identification of various organisms.  They are the most common optochin, bacitracin( 10 µg), bacitracin (0.04µg), and novobiocin. The most common antimicrobial agents and their uses: Optochin (ethylhydrocupreine hydrochloride)-5µg: Mode of action: Optochin is a quinine derivative. It selectively inhibits the growth of S. pneumoniae at very low concentrations i.e. 5 mg/mL or even less. It may also inhibit viridans streptococci, but requires higher concentrations....