Outline topic # 2
NOMENCLATURE & CLASSIFICATION
MLT 303-Med. Micro 1
Dr. Bernard C. Silvala
Nomenclature & Classification of Microorganisms
Taxonomy- Organizing, classifying and naming living things
 Identifying and classifying organisms according to specific criteria
 Each organism placed into a classification system
Domain collection similar to kingdoms
 Kingdom: collection of similar phyla
 Phylum collection of similar classes
 Class collection of similar orders
 Order collection of similar families
 Family collection of similar genera
 Genus group of related species
 species group of related isolates or strains
3 Domains
 Eubacteria
true bacteria, peptidoglycan
 Archaea
odd bacteria that live in extreme environments, high salt, heat, etc. (usually
called extremophiles)
 Eukarya
4 main kingdoms:
Protista
Fungi
Plantae
Animalia
Species and Subspecies
 Species
collection of bacterial cells which share an overall similar pattern of traits in
contrast to other bacteria whose pattern differs significantly
 Strain or variety
culture derived from a single parent that differs in structure or metabolism from
other cultures of that species (biovars, morphovars)
 Type
subspecies that can show differences in antigenic makeup (serotype or serovar),
susceptibility to bacterial viruses (phage type) and in pathogenicity (pathotype)
Classification Systems in the ProKaryotes
Outline topic # 2
NOMENCLATURE & CLASSIFICATION
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MLT 303-Med. Micro 1
Dr. Bernard C. Silvala
Microscopic morphology
Macroscopic morphology – colony appearance
Physiological / biochemical characteristics
Chemical analysis
Serological analysis
Genetic and molecular analysis
• DNA analysis using genetic probes
• Nucleic acid sequencing and rRNA analysis
Taxonomic Term
 Phenotype can be used in the process identification of bacteria
Based on:
Microscopic morphology (Gram -. Gram +, cocci, rod, vibro, spirillum, etc.)
Metabolic capabilities (Anaerobic, aerobic, Produces SH, Lactose, etc)
Serology- do specific antibodies attach
 Genotype : is term use to Identify Prokaryotes. Based on Nucleic acid probes
Using numerous technologies to identify organisms based (PCR,
Sequencing ribosomal RNA genes)
 Biotype (Biochemical typing)
Biochemical tests can be used to identify species
They can also be used to identify strains by tracing specific biochemical
characteristics called biovar or biotype
 Serotype (Serological typing)
Identification made based on differences in serological molecules
Serological characteristics are termed serovar or serotype
ARCHAEA:
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Live in the most extreme habitats in nature, extremophiles
Adapted to heat, salt, acid pH, pressure and atmosphere
Includes: methane producers, hyperthermophiles, extreme halophiles, and
sulfur reducers
Naming Microorganisms
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Binomial (scientific) nomenclature
Gives each microbe 2 names:
The first name designates the genus (plural: genera) and its first letter is
capitalized
The second name is the specific epithet, and it is not capitalized
Outline topic # 2
NOMENCLATURE & CLASSIFICATION
MLT 303-Med. Micro 1
Dr. Bernard C. Silvala
 e.g. Bacillus anthracis; Bacillus is the genus and anthracis is the species name.
Staphylococcus aureus (S. aureus)
Bacillus subtilis (B. subtilis)
Escherichia coli (E. coli)
SUPPLEMENTAL READING:
Microbiology Demystified by Tom Betsy, 2005. Chapter 4: Eukayocytes and
Prokaryocyte, page 67.
Textbook: Microbiology: introduction 10th edition: Tortora, Funk, case