Mantoux (Tuberculin) Test is used as a laboratory diagnostic aid to detect reactions of individuals to tuberculin i.e. purified protein derivative (PPD). A tuberculin is any preparation that contains tuberculoprotein – which is usually obtained by the filtration of a culture of tubercle bacilli. PPD is the test antigen in the mantoux skin test. It […]
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Biochemical Tests in Microbiology Lab, Immunology & Immune System
Haemolysis is the breakdown of red blood cells (RBCs). Certain bacterial species including Streptococcus and Staphylococcus species produce extracellular enzymes that lyse or breakdown the red blood cell component of whole blood. Such bacteria require additional growth factors for growth; and when such bacterial species are cultured in vitro in culture media (e.g. blood agar),
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Biochemical Tests in Microbiology Lab
The CAMP test (named for the original authors: Christie, Atkins, and Munch-Petersen) was first used in the identification of group B streptococci (GBS). Group B streptococci secrete a protein called CAMP factor or “protein B” that interacts with the beta-hemolysin produced and secreted by Staphylococcus aureus, this results in enhanced or synergistic hemolysis. The CAMP
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Biochemical Tests in Microbiology Lab
Hydrogen sulphide test: Hydrogen sulphide test is used to identify bacteria that produce the gas, hydrogen sulphide (H2S). Hydrogen sulphide (H2S) production test is used for the detection of hydrogen sulphide (H2S) gas produced by an organism. H2S is produced by bacteria during the anaerobic metabolism of sulphur containing amino acids (e.g. cysteine). This gas
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Biochemical Tests in Microbiology Lab
Methyl red test is used to identify pathogenic bacteria that produce acid from glucose phosphate. Some bacterial isolates ferment glucose through the mixed acid fermentation pathway to produce several acids including acetic acid, formic acid and lactic acid. Production of steady amounts of acids by these microorganisms will result in a pH level that is
Amylase (Starch hydrolysis) test is used to identify bacteria that hydrolyze starch (including amylopectin and amylose) with the help of the enzyme amylase. Amylase is an enzyme that hydrolyzes starch into maltose, glucose, and dextrin’s. Some bacterial isolates including Bacillus and Clostridium have the ability to produce α-amylase and other enzymes that degrade starch molecules
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Biochemical Tests in Microbiology LabBlood agar haemolysis is used to determine the haemolytic ability of some pathogenic microorganisms including Streptococcus pneumoniae, Staphylococcus aureus and Micrococcus species. Some pathogenic bacteria are capable of expressing some specific exotoxins known as haemolysin – which reacts as antibodies homologous to the surface antigens of red blood cells (erythrocytes). This phenomenon allows these organisms
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Biochemical Tests in Microbiology Lab
Satellitism test is a culture-based test which is used to identify Haemophilus influenzae in the laboratory. Haemophilus influenzae is a fastidious bacterium that requires both X factor (haemin) and V factor (NAD or NADP) for growth. Blood agar lacking any of these growth factors will not support most strains of H. influenzae. When grown in
Nitrate reduction test is used to identify pathogenic bacteria that have the ability to convert nitrate (NO3–) to nitrite (NO2–). Nitrate reduction test is used for the differentiation of members of Enterobacteriaceae on the basis of their ability to produce nitrate reductase enzyme – that hydrolyze nitrate (NO3–) to nitrite (NO2–), which may then again be
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Biochemical Tests in Microbiology Lab
Triple sugar iron agar (TSIA) is a differential agar medium used to different lactose-fermenting Enterobacteriaceae from non-lactose fermenting enterobacteria. The medium usually contains three sugars viz: sucrose, glucose, and lactose, and phenol red as a pH indicator. TSIA is a synonymous biochemical test to Kliger’s iron agar (KIA) test. Both TSIA and KIA are used
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Biochemical Tests in Microbiology Lab