Introduction to Microbiology and Taxonomy

Microbiology

The study of microbes

Microbes

ubiquitous, virtually everywhere

Cellular

(Living cells) bacteria, Archae, protozoa, and certain types of algae and fungi

Acellular

(non-living particles) viruses and prions as they are not to be considered as living

Pathogens

Microbes that causes disease

Infectious disease

Colonizes the body, causing a disease. Example MRSA infection and gas gangrene

Microbial Intoxication

Produces a toxin in vitro. When ingested causes a disease. Example Staphylococcal food poisoning and Foodborne botulism

Nonpathogens

Microbes that do not cause disease

Opportunistic pathogens

Microbes that do not cause disease under ordinary conditions but have the potential to cause disease should the opportunity present itself.

Normal flora (or microbiota)

Microbes that live on and in the human body and, for the most part, are of benefit to us.

Saprophytes

Microbes that are involved in the decomposition of dead organisms and the waste products of living organisms.

Bacteria and protozoa

the first microbes to be observed by humans.

1632-1723 Anton Van Leeuwenhoek

Father of Microbiology, Father of Bacteriology, Father o Protozoology

1632-1723 Anton Van Leeuwenhoek

First person to see live bacteria and protozoa using his microscope. Observed various tiny living creatures, which he called “animalcules.”

1822-1895 Louis Pasteur

Developed Pasteurization

Pasteurization

a way of killing pathogens in many types of liquids involving heating.

1822-1895 Louis Pasteur

Discovered what happens during Alcohol fermentation

Aerobes

organisms that require oxygen.

Anaerobes

organisms that don’t require oxygen.

1843-1910 Robert Koch

Discovered Koch’s postulates

Koch’s postulates

a set of four criteria used to establish a causal relationship between a microorganism and a disease.

1843-1910 Robert Koch

Discovered Tuberculin, a protein derivative from M.tuberculosis which led to the development of a skin test valuable in diagnosing tuberculosis.

1843-1910 Robert Koch

Discovered B. anthracis, that it produces spores capable of resisting adverse reactions.

1843-1910 Robert Koch

developed methods of cultivating bacteria on solid media together with his colleague R.J Petri who created the Flat glass dish (now called Petri dish)

Abiogenesis or “spontaneous generation”

the idea that life can arise spontaneously from non-living matter.

Biogenesis

the idea that life can only arise from preexisting life.

Rudolf Virchow in 1858

First proposed Biogenesis

Taxonomy

The science of living organisms consists of three separate but interrelated areas: classification, nomenclature, and identification

Classification

Arrangement of organism into taxonomic group (known as taxa or taxon)

Nomenclature

Assignment of name to the various taxa according to international rules

Identification

The process of identification; whether the isolate belongs to an established taxa or represents a previously unidentified species.

The Seven Taxa Sequence in the Classification of Organisms

Kingdom, Phylum, Class, Order, Family, Genus, Species

Kingdom

A very large grouping based on fundamental traits such as cell type and nutrition.

Phylum

Groups organisms within a kingdom by major body plans or organization.

Class

Divides a phylum into organisms that share more specific features.

Order

Narrows a class by even finer traits, often anatomical or reproductive.

Family

Clusters closely related genera that share key structural or genetic markers.

Genus

A group of very closely related species.

Species

The most specific rank; organisms that can interbreed and produce fertile offspring.

Genotype

organism’s complete collection of genes

Phenotype

complete collection of organism’s physical characteristics

Binomial System of Nomenclature

provides a standardized, two-part naming convention for all organisms. This ensures all organism have a unique and universally recognized name

Genus

First name, written in uppercase, frequently designated a single-letter abbreviation.

Specific Epithet

second name, lowercase

sp. (singular) and spp. (plural)

abbreviated when species is not specified