Transcript How to Make a Dichotomous Key From a Table of Bacterial Characteristics

How to Make a Dichotomous
Key From a Table of Bacterial
Characteristics
(for use in running the minimum
number of tests in identifying an
unknown bacterium)
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
positive
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
Galactose fermentation
positive
Alcaligenes faecalis
Aeromonas hydrophila
negative
Citrobacter freundii
Pseudomonas fluorescens
positive
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
Galactose fermentation
positive
Alcaligenes faecalis
Aeromonas hydrophila
H2S production
positive
negative
Aeromonas
hydrophila
Alcaligenes
faecalis
negative
Citrobacter freundii
Pseudomonas fluorescens
positive
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
positive
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Galactose fermentation
positive
Alcaligenes faecalis
Aeromonas hydrophila
H2S production
positive
Aeromonas
hydrophila
negative
negative
Citrobacter freundii
Pseudomonas fluorescens
Litmus milk
acid
Alcaligenes Citrobacter
faecalis
freundii
alkaline
Pseudomonas
fluorescens
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
positive
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Acid-fast staining
Galactose fermentation
positive
Alcaligenes faecalis
Aeromonas hydrophila
H2S production
positive
Aeromonas
hydrophila
negative
acid fast
negative
Citrobacter freundii
Pseudomonas fluorescens
Litmus milk
acid
Alcaligenes Citrobacter
faecalis
freundii
alkaline
Pseudomonas
fluorescens
not acid fast
Mycobacterium smegmatis
Corynebacterium xerosis
Mycobacterium leprae
Streptococcus
pneumoniae
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
positive
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Acid-fast staining
Galactose fermentation
positive
Alcaligenes faecalis
Aeromonas hydrophila
H2S production
positive
Aeromonas
hydrophila
negative
acid fast
negative
Citrobacter freundii
Pseudomonas fluorescens
Litmus milk
acid
Alcaligenes Citrobacter
faecalis
freundii
alkaline
Pseudomonas
fluorescens
not acid fast
Mycobacterium smegmatis
Corynebacterium xerosis
Mycobacterium leprae
Streptococcus
pneumoniae
Catalase produced
positive
Mycobacterium
leprae
negative
Mycobacterium
smegmatis
Table of Characteristics for Eight Bacteria
Organism
Characteristics
Alcaligenes faecalis
Gram negative bacillus, acid-fast negative, ferments galactose,
catalase positive, motile, alkaline with litmus milk, not hemolytic, H2S
negative
Citrobacter freundii
Gram negative bacillus; acid-fast negative, does not ferment galactose,
catalase positive, non-motile, acid produced in litmus milk, not
hemolytic, H2S negative
Pseudomonas
fluorescens
Gram negative bacillus, acid-fast negative, does not ferment galactose,
catalase positive, non-motile, alkaline in litmus milk, hemolytic, H2S
negative
Streptococcus
pneumoniae
Gram positive oval coccus found as streptococci, acid-fast negative,
galactose fermentation negative, catalase negative, non-motile, acid in
litmus milk, hemolytic, H2S negative
Mycobacterium
smegmatis
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-negative,, non-motile, alkaline in litmus
milk, catalase positive, not hemolytic, H2S negative
Mycobacterium leprae
Gram positive club-shaped bacilli, acid-fast positive, galactose
fermentation negative, catalase-positive, non-motile, alkaline in litmus
milk not hemolytic, H2S negative
Corynebacterium
xerosis
Gram positive club-shaped bacilli, acid-fast negative, galactose
fermentation positive, non-motile, acid from litmus milk, catalase
positive, not hemolytic, H2S negative
Aeromonas hydrophila
Gram negative bacilli, acid-fast negative, ferments galactose, catalase
positive, motile, acid from litmus milk, not hemolytic, H2S positive
Dichotomous Key to Identifying Eight Bacteria
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Streptococcus pneumoniae
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Aeromonas hydrophila
Gram stain
negative
positive
Alcaligenes faecalis
Citrobacter freundii
Pseudomonas fluorescens
Aeromonas hydrophila
Mycobacterium smegmatis
Mycobacterium leprae
Corynebacterium xerosis
Streptococcus pneumoniae
Acid-fast staining
Galactose fermentation
positive
Alcaligenes faecalis
Aeromonas hydrophila
H2S production
positive
Aeromonas
hydrophila
negative
acid fast
negative
Citrobacter freundii
Pseudomonas fluorescens
Litmus milk
acid
Alcaligenes Citrobacter
freundii
faecalis
alkaline
Pseudomonas
fluorescens
not acid fast
Mycobacterium smegmatis
Corynebacterium xerosis
Mycobacterium leprae
Streptococcus
pneumoniae
Catalase produced
positive
Mycobacterium
leprae
negative
Hemolysis
positive
Mycobacterium Streptococcus
smegmatis
pneumoniae
negative
Corynebacterium
xerosis