Microbial Taxonomy

• Taxonomy: The science of biological classification
• Taxon/Taxa is a group or level of classification or hierarchy categorized at different levels
• Systematics/Phylogeny is the study of diversity of organisms and their evolutionary relationship
• Dichotomous key is a tool used for assigning an organism to a specific taxonomic category
• Taxonomic categories or hierarchy: An ordered group of taxonomic ranks used to classify organisms from general to specific
• Major taxonomical characteristics: Morphological, Physiological, Geographic and behavioral, Molecular, Ecological
• Phenotypic (Phenetic) classification system is groups do not necessarily reflect genetic similarity or evolutionary relatedness, groups are based on convenient observable characteristics
• Genotypic (Phylogenetic) classification system is considers characteristics of the genome
• Classification hierarchy: Family, Genus, Species
• Species is groups of populations that can potentially interbreed freely within and among themselves, collection of bacterial strains that share common physiologic and genetic features and differ notably from other microbial species
• Subspecies: Biotype, Serotype, Genotype
• Biotype is a group of organisms having the same or nearly the same genotype
• Serotype is a group of organisms within a species that have the same type and number of surface antigens
• Genotype is may be given to groups below the subspecies level that share specific but relatively minor characteristics
• Clone is a population of cells derived from a single parent cell and identical
• Strain differentiation methods: Immunological reactions, Protein profiling, Flow cytometry, Phage typing
• Nomenclature is the branch of taxonomy concerned with the assignment of names to taxonomic groups in agreement with published rules
• Carolus Linnaeus introduced a formal system of classification dividing living organisms into two kingdoms— Plantae and Animalia
• The naming of microorganisms is according to established rules and guidelines set forth in the International Code of Nomenclature of Bacteria (ICNB) or the Bacteriological Code (BC)
• The taxonomic classification scheme for prokaryotes is found in Bergey's Manual of Systematic Bacteriology
• Rules governing microbial nomenclature is limited to two taxa, genus and species known as binomial nomenclature
• Pointers on how to write a scientific name: Suffixes for order and family, Genus and specific epithet (species) are printed underlined or italicized, Genus name is always capitalized, species name is lowercase, Name may be abbreviated using first letter of genus and full species name
• Identification is the process of determining a particular (organism) belongs to a recognized taxon. The process by which a microorganism's key features are delineated.
• Identification methods: Genotypic characteristics, Phenotypic characteristics
• Genotypic characteristics relate to an organism's genetic makeup, including the nature of the organism's genes and constituent nucleic acids
• Phenotypic characteristics are based on features that can be observed or measured
• Genus name is always capitalized in first letter and is always a noun
• Species name is lowercase in first letter and is usually an adjective
• Scientific name: Klebsiella pneumoniae
• Scientific name abbreviation is first letter of genus designation followed by a period (.) and the full species name, which is never abbreviated
• Scientific name abbreviation: S. aureus
• Nomenclature is a component of taxonomy
• Naming of bacteria is based on cell arrangement
• Genotypic characteristics is relate to an organism's genetic makeup, including the nature of the organism's genes and constituent nucleic acids
• Genotypic characteristics: Hair color, height, eye color
• Phenotypic characteristics is features beyond the genetic level, including both readily observable characteristics and features that may require extensive analytic procedures to be detected
• Phenotypic characteristics: Skin color
• Identification methods in bacterial identification: Microscopic morphology, Macroscopic morphology, Physiological/biochemical characteristics, Chemical analysis, Phage typing, Serological analysis, Pathogenicity, Genetic and molecular analyses
• The Three Domain System divides all living organisms into Domain Archaea, Domain Bacteria, and Domain Eukarya
• Ribosomal RNA (rRNA) data suggests that Archaea & Eukarya may share a more recent common ancestor with each other than with Bacteria