Day 1: Question 1 - Preliminary ID Flashcards
What are the basic characteristics for staphylococcus
(6)
No haemolysis
No odour
Catalase positive*
Oxidase negative
KoH negative
What Preliminary ID test results indicate Staphylococci
Cocci
Gram positive
Catalase positive
How do you know a GP and catalase cocci is a staphylococcus and not a micrococcus?
Micrococcus are extremely small
Staphylococcus are so much more common
What five tests would you do to speciate staphylococci?
DN’ase test
Mannitol salt agar
SAIDE agar -> Chromid S.aureus ELITE agar
Novobiocin susceptibility test
Coagulase test -> Staphaurex P test -> protein A test
What are the three classifications of streptococci
Alpha haemolytic
Beta haemolytic
Gamma haemolytic
What are the basic characteristics for streptococci
(4)
Could be alpha, beta or gamma haemolyisis
Gram positive
Aerobe
Catalase negative*
What tests would you carry out for streptococci?
(6)
Lancefield grouping (b) (g)
Bacitracin (b)
Optochin (a)
MacConkey (g)
Bile Aesculin (g)
Vancomycin (g)
What are the basic characteristic test results for enterococci?
(4)
Cocci*
Gram positive*
Aerobe*
Catalase negative *
What’s the most important step when identifying streptococci/enterococcus?
If you have a gram positive, aerobe, catalase negative cocci, you need to be able to identify haemolysis
Only certain tests carried out for each type of haemolysis
Gamma haemolysis usually means an enterococcus
What are the basic characterisation results for Neisseria or Moraxella?
Cocci
Gram negative
Diplococci
KOH positive
Catalase positive
Oxidase negative
What tests do you carry out for presumptive Neisseria or Moraxella?
(3)
TAXO
DN’ase
Catarrhalis test (M. Catarrhalis)
How could you distinguish Moraxella from Neisseria on an agar plate?
Moraxella is pushable
What are the basic characteristic test results for Haemophilus
Gram negative*
Aerobe*
Coccobacilli*
Facultative - only om choc*
List the tests used to confirm haemophilus
Factor X, V, XV test
What are the basic characteristic test results for bacillus species?
Bacilli
Gram positive
Aerobe
Sporing
Catalase
What tests should you carry out for bacillus
(2)
PEMBA
Motility
What are the basic characteristic test for Corynebacteria?
(5)
Bacilli
Gram positive
Aerobe
Non sporing
Catalase positive
What are the tests for corynebacteria
(3)
Trehalose
Urease
Tinsdale
What are the basic characterisation test results for enterobacterales?
(5)
Bacilli
Gram negative
Aerobe
Rod
Oxidase negative*
What tests should you carry out for enterobacterales
Biochemical testing -> with MacConkey purity plate
Brilliance chromogenic agar
Why is the MacConkey plate so important in the biochemical test for enterobacterales?
Enterobacterales are classified based on their ability to ferment lactose -> pink colonies = lactose fermenter, yellow colonies = non lactose fermenter
What are the lactose fermenter enterobacterales?
Escherichia
Enterobacter
What are the non lactose fermenter enterobacterales?
Salmonella
Proteus
What are the basic characterisation tests for pseudomonas?
(5)
Bacilli
Gram negative
(Facultative) Aerobic
Rod
Oxidase positive*
What tests are used for pseudomonas
(2)
Growth at different temperatures -> 42 degrees and 4 degrees
Kings A medium
What are the basic characteristic test results for clostridium
Bacilli*
Gram positive*
(Facultative) Anaerobe*
Sporing*
What are the tests for clostridium
(4)
Metronidazole and anaerobic growth
Egg yolk
Naglar
Lactose-gelatin
How can you distinguish between moraxella and neisseria?
Moraxella have larger pushable colonies
What are the three clinically significant staphylococci?
Aureus
Epidermidis
Saprophyticus
What are the five clinically significant strains of streptococci?
Strep pneumonia
Strep pyogenes
Strep viridans
Strep mutans
Strep agalactiae
How can you tell a strep is strep pneumoniae from how is appears on a blood agar plate and under a microscope
Alpha haemolysis
Draughtsman colonies or mucoid colonies
Lanceolate -> flame shaped cocci
What strep strains have alpha haemolysis
S pneumoniae (most likely)
S viridians
What strep strains have beta haemolysis
S pyogenes (most likely)
S agalactiae
What strep strains have gamma haemolysis
S. bovis however any gram positive cocci which are catalase negative and don’t have haemolysis are more than likely enterococcus than strep
Which are the most significant Lancefield grouping?
(4)
Group A = Strep pyogenes
Group B = Strep agalactiae
Group C = Strep equi or strep equisimilis
Group D = Enterococcus faecalis or Strep bovis
What are the three clinically significant species of Enterococcus
E. faecalis
E. faecium
E. durans
What should you do if you ID an enterococcus?
(2)
Suggest vancomycin susceptibility as some strains are resistant
Suggest chromogenic VRE Medium
How could you identify Neisseria before carrying out tests
(3)
Seen in pairs
Often kidney shaped cocci
Grown on chocolate agar
How could you identify moraxella before carrying out tests
(3)
Cocci in pairs
Tend to resist decolorisation
Grown on chocolate agar
List the six clinically significant strains of Neisseria
N. gonorrhoeae
N. meningitidis
N. pharyngitis
N. lactamica
N. flavescens
N. sica
List the clinically significant strains of Bacillus species
(4)
Bacillus anthracis
Bacillus cereus
Bacillus subtilis
Bacillus thuringenesis
What would indicate B. anthrax in a case study?
(3)
Food poisoning from eating contaminated fried rice
Contact with animals
Anthrax -> skin (blister), lung, intestine, injection
How could you identify B. anthrax from a gram stain?
(3)
Medusa head -> large tangled chains of bacilli
Large, grey-white colonies
No haemolysis
What species of Bacillus have B-haemolysis
Bacillus cereus
Bacillus thuringenesis
What species of Bacillus have alpha-haemolysis
B.anthrax (usually no haemolysis)
B. subtilis (definitely alpha)
What are the clinically significant species of Corynebacteria
C. diptheria
C. ulcerans
C. pseudotuberculosis
Diptheroids
How would you know if you have a corynebacteria and not a listeria species
Corynebacteria grow on Tinsdale but listeria wont
What are the clinically significant species of Clostridium
C. botulinum
C. difficile
C. perfringens
C. tetani
Where is C. botulinum found and what infections does it cause?
(2)
Its an organism that produces a toxin in food/wound
It causes botulism
Where is C. difficile found and what infections does it cause?
Often overgrows commensals in the gut during antibiotic therapy and can cause pseudomembranous colitis
What infection does C. tetani cause
Tetanus
How do you differentiate pseudomonas from enterobacterales
Pseudomonas is oxidase positive
List the five clinically significant species of Haemophilus
H. influenzae
H. parainfluenzae
H. ducreyi
H. aegyptius
H. aphrophilus
What species of proteus are clinically significant
Proteus mirabilis
Proteus vulgaris
How can you identify proteus on an agar plate
Swarming colonies
What are the clinically significant strains of pseudomonas
P. aeruginosa
P. fluorescence
List the genera that make up the family bacteroidaceae
(4)
Bacteroides
Poryphyromonas
Prevotella
Fusobacterium
What are the three clinically significant species of bacteroides?
B. fragilis
B. oralis
B. ureolyticus
What are the five strains of fusobacterium
F. nucleatum
F. necrophorum
F. periodonticum
F. mortiferum
F. necrophorum
What is the only clinically significant strain of pasteurella
P. multocida
What is the only clinically significant strain of prevotella?
Pr. melaninogenica
