Biochemical tests are laboratory procedures that use specific chemical reactions to identify and characterize microorganisms, such as bacteria. These tests are often used to identify the presence of specific enzymes or metabolic pathways in a microorganism, which can help to distinguish it from other microorganisms.
Some common biochemical tests used in bacteriology include:
These are just a few examples of the many different biochemical tests that are used in bacteriology. Biochemical tests can be useful for identifying and classifying bacteria, and for understanding their metabolism and ecological role.
Test Name Casein Hydrolysis Test Detection Enzyme caseinase producing microorganisms Uses To show that some microorganisms can make enzymes outside of their cells that can break down the milk protein casein. Result A clear, transparent zone can be seen around the area where the colonies are growing, or sometimes under the area where the colonies … Read more
Cetrimide Selective Agar is a solid medium that is recommended for use in qualitative procedures for selective isolation and presumed identification of Pseudomonas aeruginosa and other nonfermenting, gram-negative bacilli.
Test Name Deoxyribonuclease (DNase) Test Detection DNases enzyme Uses To find out if an organism can break down DNA and use it to get carbon and energy so it can grow.To distinguish Staphylococcus aureus from other Staphylococci. Result DNase Test Agar: After adding 1N HCl, a clear zone forms around the growth line, but the … Read more
Test Name Growth at 42 Test Purpose This test distinguishes pyocyanogenic pseudomonas from other Pseudomonas species.Determine an organism’s capacity to live at a temperature of 42°C.To distinguish fermentative bacteria from non-fermentative bacteria. Uses The test is used to determine an organism’s capacity to grow at 42°C.This test distinguishes pyocyanogenic pseudomonas from other Pseudomonas species. Result … Read more
What is Bile Solubility Test? Definition of Bile Solubility Test The bile solubility test is a biochemical assay used to differentiate Streptococcus pneumoniae from other alpha-hemolytic Streptococci based on the lysis of bacterial cells in the presence of specific bile salts. Objectives of Bile Solubility Test In essence, the bile solubility test is a pivotal … Read more
Leucine aminopeptidase (LAP) is an enzyme used to distinguish catalase-negative, gram-positive cocci of Aerococcus and Leuconostoc (LAP test negative) from other organisms in the group, such as Streptococcus, Enterococcus, Lactococcus, and Pediococcus (almost always positive).
The pancreas secretes an enzyme called lipase that aids in the digestion of fatty foods. High levels of lipase in the blood may indicate pancreatitis, a disorder characterised by the inflammation and enlargement of the pancreas. Other pancreatic difficulties, certain drugs, and diseases and disorders include kidney failure, cancer, and gallbladder and oesophagus troubles can … Read more
A lipid is a high-energy, low-molecular-weight molecule. After being taken in by the cell, they are processed via aerobic respiration to generate ATP (adenosine triphosphate), the energy currency of the cell (ATP). Other metabolic processes may also use the components to synthesise essential cellular protoplasm. However, degradation is necessary before bacteria can absorb them. Lipases … Read more
The purpose of the malonate test is to see if the organism can get all of its energy from malonate.
The oxidase enzyme is a key factor in distinguishing Staphylococcus from Micrococcus, and the Microdase Disk is a reagent-impregnated disc recommended for use in qualitative procedures.
MUG Disk is a reagent-coated disc that can be used to quickly and probably identify Escherichia coli in qualitative procedures. MUG stands for 4-Methylumbelliferyl-β-D Glucuronide and it acts as a substrate for the organisms that have the enzyme β-glucuronidase. This enzyme is found in 97% of E. coli strains. Salmonella, Shigella, and Yersinia are also … Read more
The novobiocin (antibiotic) differentiation disc can be used in the Novobiocin Susceptibility Test to help make a preliminary distinction between Staphylococcus saprophyticus and other coagulase-negative staphylococci (CoNS) in clinical (urinary) specimens.
Hugh and Leifson published the details of the oxidative-fermentative (OF) test in 1953. “had discovered that some bacteria made acid from carbohydrates solely under aerobic settings and others created acid both under aerobic and anaerobic conditions,” the authors write of previous microbiological research. Fermentation was once characterised as the process by which acid was produced … Read more
o-Nitrophenyl-b-D-Galactopyranoside (ONPG) Test Overview In order for bacteria to ferment lactose, two enzymes, permease and beta-galactosidase, must be present. Lactose is transported into the bacterial cell wall by permease and subsequently hydrolyzed by beta-galactosidase into glucose and galactose. bacteria are able to digest glucose and galactose. Some organisms, however, appear to be late or non-fermenters … Read more
The capability of an organism to utilise the substrate pyruvate can be tested with Pyruvate Broth. Those organisms that can metabolise pyruvate can be distinguished from those that can’t thanks to the presence of the test substrate pruvate. The ability to distinguish between Enterococcus faecalis and Enterococcus faecium relies on this trait. The broth made … Read more
The ability to develop in the presence of varying concentrations of sodium chloride (NaCl) has been used to distinguish between various bacteria.
What is Sulfur Reduction Test? Definition of Sulfur Reduction Test The Sulfur Reduction Test is a biochemical assay used to determine the ability of microorganisms to metabolize sulfur-containing compounds, resulting in the production of hydrogen sulfide (H2S) gas. This test aids in differentiating and identifying bacterial species based on their sulfur-reducing capabilities. Objective of Sulfur … Read more
Some bacteria make substances that other bacteria need to grow. The X factor and the V factor are two such substances. The heat-stable X-factor can be protoporphyrin IX, hemin, or other iron-containing porphyrins. It can be found in red blood cells and outside of them in the blood. The heat-sensitive V-factor may be nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP), and it is mostly found inside red blood cells. The X and V factor test or a disc test can be used to find out if a bacterium depends on its X factor or its V factor. The results can help identify the bacteria.
About Salmonella Typhi Salmonella enterica subspecies enterica serovar Typhi (Salmonella typhi) causes typhoid fever in humans. Typhoid fever is a systemic illness that causes fever. It is spread through faeces and food or water, mostly in the developing world. At least 16–20 million people get typhoid fever each year around the world, and about 600,000 … Read more
The Bacitracin susceptibility test is one of the antimicrobial disc tests used to distinguish between group A and other -hemolytic Streptococci.
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