Bacteriology

Unicellular

Organisms composed of a single cell.

Prokaryotic

A type of cell that lacks a nucleus and membrane-bound organelles, characteristic of bacteria.

Nucleoid

The region in a bacterial cell where the bacterial chromosome is located; consists of a single circular piece of DNA.

Plasmid

Extra-chromosomal DNA found in bacteria.

Gram-positive

Bacteria that retain the crystal violet stain used in the Gram staining procedure, appearing purple under a microscope.

Gram-negative

Bacteria that do not retain the crystal violet stain and appear red or pink under a microscope after Gram staining.

Exotoxins

Toxic substances secreted by bacterial cells, produced by both gram-negative and gram-positive bacteria.

Invasiveness

The ability of some bacteria to enter deep into tissues by disrupting cell membranes and tissue matrix.

Transformation

The uptake and incorporation of naked DNA into a bacterial cell.

Transduction

The transfer of bacterial genes by a bacteriophage (virus-infected bacterium).

Conjugation

The transfer of genetic material from a donor bacterial strain to a recipient strain.

Gram Staining

A microscopic exam that divides bacteria into four major groups based on their cell wall structure.

Acid-Fast Staining

A microscopic exam used to detect acid-fast bacteria, such as Mycobacterium Tuberculosis.

Culture

The process of inoculating specimens onto artificial media to allow the growth of bacteria for identification.

Susceptibility Tests

Tests conducted to determine which antibiotics are most effective against specific bacteria.

Capsule

A protective layer superficial to the cell wall in bacteria.

Flagella

Structures used by bacteria for locomotion.

Pili

Hair-like structures used by bacteria for attachment and genetic exchange.

Cocci

Spherical-shaped bacteria.

Bacilli

Rod-shaped bacteria.

Spirochete

A type of bacteria that is spiral-shaped.

Spirilla

A type of bacteria that is also spiral-shaped but is typically less flexible than spirochetes.

Endotoxin

A cell wall component of gram-negative bacteria that acts as a toxin.

Antibiotic Resistance

A natural consequence of drug exposure resulting from the use and overuse of antimicrobial agents.