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Microbial Identification and Classification - Coggle Diagram
Microbial Identification and Classification
Taxonomy
Classification
Arrange into similar or related groups
Nomenclature
System of assigning names
Identification
Characterizing a microbe to determine groups where it belongs
Prokaryotes
Classifying
Based on phenotypic traits
Size
Shape
Staining
Metabolic capabilities
Drawbacks
Similar organisms may be distantly related
Closely related organisms may appear dissimilar
New molecular techniques more accurate
DNA sequences --> evolutionary chronometers
Evolutionary relatedness
Three domain system
Compared ribosomal RNA nucleotide sequences
Evolutionary relatedness
Taxonomic hierarchies
Phylogenic trees
Evolutionary relatedness
Horizontal gene transfer
Identifying
Microscopy, culture characteristics, nucleic acid analysis
Clinical settings
Specimen collection
Phenotypic characteristics
Microscopic morphology
Initial step
Size, shape, staining
Gram stain to start appropriate therapy
Culture characteristics
Colony morphology
Differential media aids in identification
Metabolic capabilities
Biochemical tests
More certainty of identification
Catalase test
API test strip
Relies on dichotomous key
Serology
Use of antisera from animals
Animals blood plasma contain antibodies
Proteins polysaccharides
Serve as identifying markers
Fatty acid analysis (FAME)
Useful in identification
Treated to release fatty acids
Converted to fatty acid methyl ester
Separated and measured via gas chromotography
Detecting specific nucleotide sequences
NAATS
PCR
Detection of small numbers of organisms
Detection of organisms that cannot be cultured
Nucleic acid probes
Probe
Single stranded nucleic acid
Complementary to sequence of interest
Tag
Only detects single species/strain
Characterizing strain differences
Biochemical typing
Biovar
Serological typing
Proteins and carbohydrates can be used as markers
E.Coli distinguished by antigenic type of flagella
Molecular typing
DNA structure distinguish phenotypically identical strains
Phage typing
Differences in bacterial strain susceptible to bacteriophage
Replaced by molecular methods
Antibiograms
Distinguish bacterial strains
Replaced by molecular techniques