Microbiology Techniques and Bacterial Characteristics

These flashcards cover key microbiological techniques, bacterial characteristics, and important tests used for identifying and differentiating between various organisms.

Gram Stains

A differential stain used to classify bacteria as gram positive (purple/blue) or gram negative (red/pink).

Blood Agar

A medium used for the cultivation and differentiation of fastidious bacteria based on their hemolytic characteristics.

Acid Fast Stain

A differential stain used to identify bacteria in the genus Mycobacterium, which retain the primary stain despite acid alcohol treatment.

Myolic Acid

A waxy substance that increases the affinity of acid fast cells for the primary stain and protects them from decolorization.

Simple Stain

A staining method used to visualize the morphology, size, and arrangement of cells, making them more visible under a microscope.

Alpha Hemolysis

Partial destruction of red blood cells (RBCs) resulting in a green discoloration of the agar around colonies.

Beta Hemolysis

Complete destruction of RBCs and hemoglobin, leading to clearing of the medium around bacterial colonies.

Gamma Hemolysis

No hemolysis, characterized by simple growth without changes to the medium.

Coliform Bacteria

A broad group of gram negative, rod-shaped microorganisms, including E. coli, typically found in soil, water, and feces.

Lipase Test

A test to identify bacteria that produce the enzyme lipase, which hydrolyzes fats.

Zone of Inhibition

A clear area around an antibiotic disc on agar, indicating where bacteria cannot grow; used to assess antibiotic effectiveness.

Ultraviolet (UV) Light

Electromagnetic energy that affects DNA by creating dimers between adjacent thymine or cytosine bases, disrupting genetic code.

Decarboxylase Test

A test that determines a microorganism's ability to produce decarboxylase enzymes, leading to an alkaline byproduct and a color change.

Amylase

An enzyme that breaks down starch into glucose, utilized in tests to determine the presence of bacteria that produce amylase.

Catalase Test

A test that identifies organisms producing catalase, as indicated by bubble production when hydrogen peroxide is added.

Citrate Test

A test to determine if an organism can use citrate as its sole carbon source, indicated by a color change in the medium.

Carbohydrate Fermentation Test

A test to determine an organism's ability to ferment carbohydrates, indicated by color changes in the medium due to acid production.

SIM Test

A test that assesses sulfur reduction, indole production, and motility in microorganisms, using specific reagents and media changes.