Posts

Recent post..

Laboratory Disinfectants.

Image
This post describes the use of disinfectants for routine laboratory decontamination of surfaces and equipment. Definitions:   Disinfectants : Disinfectants are substances that are applied to non-living objects to destroy microorganisms that are living on the objects. Microorganisms : A microorganism or microbe is a microscopic organism that comprises either a single cell (unicellular), cell clusters, or multicellular relatively complex organisms. Antiseptic : Any substance that inhibits the growth and reproduction of microorganisms. Generally includes only those that are used on living objects (as opposed to disinfectants) and aren’t transported by the lymphatic system to destroy bacteria in the body (as opposed to antibiotics ). Decontamination – A process that removes the total burden of all classes of microorganisms, usually using chemicals, heat, and/or pressure.  Disinfection – A process that reduces microbial burden on a surface or object.  Inactivation – The pro...

Biosafety Cabinet

​ Biosafety Cabinets. Definition Biosafety Cabinets (BSCs) are enclosed workspaces with a ventilated hood that is designed to contain pathogenic microorganisms during microbiological processes. The primary purpose of biosafety cabinets is to protect the laboratory personnel and the environment from the pathogenic microorganism as aerosols might be formed during the processing of such microorganisms. Biosafety cabinets are only used for certain risk group organisms and for processes that might result in aerosol formation. These cabinets are provided with HEPA-filters that decontaminate the air moving out of the cabinet. Biosafety cabinets might be confused with the laminar hood as both of these pieces of equipment work as enclosed workspaces. But, laminar hood only provides protection to the sample and not to the personnel and the environment, whereas biosafety cabinets protect all three. The use of biosafety cabinets or other such physical containment is not required in the biosafety l...

Bacteria identification series

Image
Gram positive bacteria identificstion chart

Catalase test

Image
Catalase Test- Principle, Procedure, Types, Results, Uses  What is Catalase Test? The catalase test is a biochemical test for aerobic organisms that detects the production of catalase enzyme in the organism. Catalase enzyme is a common enzyme that is found in all living beings that survive in oxygen and catalyzes the decomposition of hydrogen peroxide, releasing water and oxygen. Catalase is an essential enzyme in pathogenic organisms as it protects the organism from oxidative damage from the reactive oxygen species. The enzyme neutralizes the bactericidal effects of hydrogen peroxide, and its concentration in bacteria has been correlated with the pathogenicity of the organism. The catalase test has been extensively used over the years as it allows the differentiation of catalase-positive organisms like staphylococci from catalase-negative species like streptococci. The catalase test is useful in the presumptive characterization of most bacteria. Under the aerobic condition, 3% H2O...

Coagulase test

Image
Coagulase Test- Principle, Procedure, Types, Result, Uses Coagulase Test Definition A coagulase test is a biochemical test that is used to differentiate Staphylococcus aureus from other Staphylococci species like S. epidermidis and S. saprophyticus on the basis of the ability to produce the coagulase enzyme. The coagulase test is an important test that differentiates the species of the genus Staphylococci into two groups; Coagulase positive Staphylococci and Coagulase Negative Staphylococci. The coagulase enzyme acts as a virulence factor in some organisms as it interacts with the fibrinogen present on the host’s cell surface. Organisms with coagulase usually have a protective barrier around themselves, increasing their pathogenicity and resistance against the immune system. Coagulase is of two types; free coagulase and bound coagulase, each of which is detected by different methods. The bound coagulase is called the clumping factor and is detected rapidly by a slide test. The free c...