What are biochemical tests?

Biochemical tests are the tests used for the identification of bacterial species based on the differences in the biochemical activities of different bacteria. Bacterial physiology differs from one type of organism to another.

What are the biochemical test for gram negative bacteria?

The basic tests used are catalase, oxidase, indole, citrate, urease, and phenylalanine. With this scheme, 12 genera and 23 species can be identified using these limited biochemicals which are within the reach of most of the microbiology laboratories having limited resources.

Is a Gram stain a biochemical test?

Biochemical tests are applied to the appropriate specimen and include gram staining followed by culturing the bacterial isolate in mannitol salt agar.

How are biochemical tests used to identify bacteria?

Biochemical tests used to identify microbes To test whether bacteria contain a catalase enzyme, a microbiologist drops hydrogen peroxide into a smear of bacteria on a microscope slide. If the bacteria contain catalase, the mixture bubbles as the hydrogen peroxide decomposes into water and oxygen.

What are routine biochemistry tests?

The biochemical profile is a series of blood tests used to evaluate the functional capacity of several critical organs and systems, such as the liver and kidneys. These tests can be done on an empty stomach or not, and are usually accompanied by a complete blood count (CBC).

What are the biochemical methods?

Biochemistry techniques are Protein Purification, perfusion, Homogenization, Differential Centrifugation, Purification of LDH, Purification of LDH , LDH Enzyme assays, Protein assays, Characterization of LDH, Western blotting, Gel filtration chromatography, Protein crystallography, PCR, Ligation and transformation, …

What is h2s test?

Hydrogen sulfide is produced if the sulfur compound is reduced by the bacterial strain. This test thus determines whether the microbe reduces sulfur-containing compounds to sulfides during the process of metabolism.

What does a MacConkey agar test for?

MacConkey agar is a selective and differential culture medium for bacteria. It is designed to selectively isolate Gram-negative and enteric (normally found in the intestinal tract) bacteria and differentiate them based on lactose fermentation.

What is catalase test?

The catalase test tests for the presence of catalase, an enzyme that breaks down the harmful substance hydrogen peroxide into water and oxygen. If an organism can produce catalase, it will produce bubbles of oxygen when hydrogen peroxide is added to it. … Bubbles are a positive result for the presence of catalase.

Is motility test a biochemical test?

Motility testing is done in conjunction with other biochemical testing using special biochemical media. … Motility Indole urease (MIU) test: It is used to determine motility, indole formation, and urease production.

What bacteria is pink in color?

Serratia marcescens Bacteria A red or pink pigmented bacteria known as Serratia marcescens is thought to be the cause of the pink stuff. Serratia bacteria are common inhabitants of our environment and can be found in many places, including human and animal feces, dust, soil, and in surface waters.

How do you perform a citrate test?

Procedure of Citrate Utilization Test

  1. Streak the slant back and forth with a light inoculum picked from the center of a well-isolated colony.
  2. Incubate aerobically at 35 to 37 C for up to 4-7 days.
  3. Observe a color change from green to blue along the slant.

What are 3 methods used to identify bacteria?

Traits that can be valuable aids to identification are combinations of cell shape and size, gram stain reaction, acid-fast reaction, and special structures including endospores, granules, and capsules.

What are agar plates?

What is it? An agar plate is a thin layer of nutrient gel in a Petri dish, used to grow bacteria and fungi in the microbiology laboratory. polysaccharide derived from the cell walls of red seaweed. A variety of nutrients can be added to the agar to preferentially grow different bacteria.

What is the positive result for indole test?

A positive result is shown by the presence of a red or red-violet color in the surface alcohol layer of the broth. A negative result appears yellow. A variable result can also occur, showing an orange color as a result.

What tests are done in a hematology lab?

What Are Common Hematology Tests?

What is the most common blood test?

Complete Blood Count This test, also known as a CBC, is the most common blood test performed. It measures the types and numbers of cells in the blood, including red and white blood cells and platelets.

What tests are done in immunology?

Types of Immunology Clinical Laboratory Tests These clinical studies include IgG, IgA and IgM tests. If you are being checked for autoimmune diseases, your doctor may order specific antibody tests such as rheumatoid antibody or anti-thyroid antibodies. Infectious disease serology tests are also part of immunology.

What do biochemists measure?

The biochemist seeks to determine how specific molecules such as proteins, nucleic acids, lipids, vitamins, and hormones function in such processes. Particular emphasis is placed on the regulation of chemical reactions in living cells.

What is included in biochemistry blood test?

Biochemical tests, which measure substances (protein, sugar, oxygen, etc.) in blood and urine, are widely used in the diagnosis of diseases and the determination of treatment. One of the measurement methods makes use of the absorbance of light, and this method is widely used in blood test equipment.

What is a biochemical assay?

A biochemical assay is an analytical in vitro procedure used to detect, quantify and/or study the binding or activity of a biological molecule, such as an enzyme.

What does a positive methyl red test mean?

Interpretation. MR: If the tube turns red, the test is positive for mixed acid fermentation (one or more organic acids formed during the fermentation of glucose).

What is a SIM test?

This is a differential medium. It tests the ability of an organism to do several things: reduce sulfur, produce indole and swim through the agar (be motile). SIM is commonly used to differentiate members of Enterobacteriaceae.

What is the principle of methyl red test?

In the methyl red test (MR test), the test bacteria is grown in a broth medium containing glucose. If the bacteria has the ability to utilise glucose with production of a stable acid, the colour of the methyl red changes from yellow to red, when added into the broth culture.

Is E coli A Enterobacteriaceae?

Enterobacteriaceae are a large family of Gram-negative bacteria that includes a number of pathogens such as Klebsiella, Enterobacter, Citrobacter, Salmonella, Escherichia coli, Shigella, Proteus, Serratia and other species.

What is blood agar used for?

Blood agar is a general purpose, enriched medium often used to grow fastidious organisms and to differentiate bacteria based on their hemolytic properties. In the U.S., blood agar is usually prepared from tryptic soy agar or Columbia agar base with 5% sheep blood.

Does Micrococcus luteus grow on EMB agar?

This microbe is coccus shaped and forms in tetrads. The colony forms as a yellow, shiny round blob. … The EMB agar showed no growth or change in color, also indicating the microbe was gram positive and a non-fermenter.

What does an oxidase test test for?

Oxidase Test – Virtual Interactive Bacteriology Laboratory. The oxidase test is used to identify bacteria that produce cytochrome c oxidase, an enzyme of the bacterial electron transport chain. (note: All bacteria that are oxidase positive are aerobic, and can use oxygen as a terminal electron acceptor in respiration.

Is E coli oxidase positive?

E. coli bacteria are among the few species of lactose (LAC)-positive, oxidase-negative, gram-negative rods that are indole positive.

Which agar is used for catalase test?

A small amount of organism is collected from a well-isolated 18- to 24-hour colony with a sterile inoculating loop or wooden applicator stick and placed onto the microscope slide. However, no agar must be picked up with the colony, especially when the culture is picked up from blood agar.