Microbial Classification and Taxonomy Overview

Taxonomy

Science of classifying organisms into groups.

Phylogeny

Study of evolutionary history of organisms.

Taxon

Category of classification showing organism similarities.

Domains

Three primary classifications: Archaea, Bacteria, Eukarya.

Archaea

Prokaryotes without peptidoglycan in cell walls.

Bacteria

Includes all other prokaryotic organisms.

Eukarya

Includes all eukaryotic organisms, five supergroups.

Endosymbiotic Theory

Eukaryotes evolved from merging multiple prokaryotes.

Firmicutes

Gram-positive bacteria with low GC content.

Actinobacteria

Gram-positive bacteria with high GC content.

Tenericutes

Bacteria without a cell wall.

Deinococcus-Thermus

Gram-positive with two plasma membranes.

Cyanobacteria

Bacteria performing oxygenic photosynthesis.

Chlamydiae

Obligate intracellular parasites.

Planctomycetes

Bacteria resembling Archaea.

Proteobacteria

Diverse group of chemoheterotrophic bacteria.

Alphaproteobacteria

Includes nitrogen-fixing symbionts.

Betaproteobacteria

Includes various environmental bacteria.

Gammaproteobacteria

Includes many pathogenic bacteria.

Suffix for Phylum

-ota suffix standard for phyla names.

Fusobacteria

Phylum of anaerobic bacteria.

Rhizobium

Symbiotic nitrogen-fixing bacteria.

Rickettsia

Obligate intracellular parasite causing diseases.

Rickettsia

Obligate intracellular parasite causing various diseases.

Pelagibacter

Common marine bacterium found in oceans.

Burkholderia

Utilizes over 100 organic molecules for growth.

Bordetella

Pathogen responsible for whooping cough.

Neisseria

Causes gonorrhoea and meningococcal meningitis.

Nitrosomonas

Chemoautotrophs using nitrogen compounds for energy.

Pseudomonas

Grows on diverse organic sources; versatile bacterium.

Azomonas

Free-living nitrogen fixer in soil environments.

Azotobacter

Free-living nitrogen fixer, enhances soil fertility.

Vibrio

Pathogen that causes cholera in humans.

Chromatium

Purple sulfur bacteria involved in photosynthesis.

Escherichia

Commonly used in research; can be pathogenic.

Salmonella

Major foodborne disease cause; includes serovars.

Yersinia

Pathogen responsible for the Black Death.

Pasteurella

Causes sepsis in cattle and pneumonia in birds.

Haemophilus

Requires blood components for growth in culture.

Bdellovibrio

Bacterium that attacks and preys on other bacteria.

Myxococcus

Forms fruiting bodies; attacks other bacteria.

Helicobacter

Causes peptic ulcers and stomach cancer.

Clostridium

Causes tetanus, botulism, and gas gangrene.

Lactobacillus

Used in fermentation; important for dairy products.

Mycobacterium

Acid-fast; causes tuberculosis and leprosy.

Corynebacterium

Pathogen causing diphtheria in humans.

Frankia

Symbiotic nitrogen fixer associated with plants.

Streptomyces

Source of commercial antibiotics; common soil microbe.

Domain Archaea

Divided into Euryarchaeota and Proteoarchaeota kingdoms.

Halophiles

Archaea that thrive in high-salt environments.

Thermophiles

Organisms that grow in high-temperature habitats.

Acidophiles

Organisms that thrive in acidic environments.

Nitrifying

Archaea involved in nitrogen cycle processes.

Methanogens

Produce methane; found in anaerobic environments.

Protozoa

Unicellular eukaryotes, often pathogenic.

Helminths

Parasitic worms affecting various hosts.

Arthropods

Jointed-legged animals; transmit diseases.

Protozoa

Unicellular eukaryotes classified by movement type.

Ciliates

Protozoa with many cilia for movement.

Balantidium coli

Only pathogenic ciliate affecting humans.

Flagellates

Protozoa that move using flagella.

Dysentery

Intestinal infection causing severe diarrhea.

Amoebae

Protozoa that move using pseudopods.

Pseudopods

Cytoplasmic extensions for amoeboid movement.

Entamoeba histolytica

Pathogenic amoeba causing intestinal infections.

Apicomplexans

Non-motile protozoa relying on hosts for transmission.

Plasmodium

Genus causing malaria, transmitted by mosquitoes.

Toxoplasma gondii

Causes congenital defects, crosses placental barrier.

Algae

Photoautotrophic organisms lacking plant structures.

Diatoms

Algae producing domoic acid neurotoxin.

Dinoflagellates

Algae genera producing various neurotoxins.

Fungi

Plant-like organisms without chlorophyll, saprophytes.

Mycosis

Fungal infection affecting the body.

Dermatophytes

Fungi infecting hair, nails, and skin.

Cutaneous mycosis

Fungal infection of the skin.

Yeast

Unicellular fungi, reproduce asexually.

Saccharomyces cerevisiae

Yeast used in baking and brewing.

Candida albicans

Pathogenic yeast infecting skin and mucous membranes.

Helminths

Parasitic worms, including flatworms and roundworms.

Platyhelminths

Flatworms, including cestodes and trematodes.

Nematodes

Roundworms, a type of helminth.

Arthropods

Animals with exoskeletons and jointed appendages.

Arachnids

Include spiders, ticks, and mites.

Disease vectors

Arthropods transmitting diseases to humans.