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Gram positive cocci include what 3 major genera?
- Staphylococci - grows in grape-like clusters
- Streptococci
- grows in pairs or chains- Enterococci
- grows in pairs or chains
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What does the catalase test differentiate?
- + reaction: Staphylococci
- - reaction: Streptococci or Enterococci
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What does coagulase testing differentiate?
- + reaction: Staphylococcus aureus
- - reaction: all other Staphylococci, which are normal flora; only S. saprophyticus and epidermidis are pathogenic
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ID the bug:
- Gram-pos cocci in grape-like clusters
- Catalase and coagulase positive
- Beta-hemolytic
- Grows yellow colonies on mannitol-salt agar
Staphylococcus aureus
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ID the bug:
Gram-pos cocci in pairs/chains
Catalase negative
Alpha-hemolytic
Infects bloodstream and CNS
- Streptococcus pneumoniae, aka Viridans Strep
- Most common alpha-hemolytic Streptococcus
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ID the bug:
Gram-pos cocci in pairs/chains
Catalase negative
Beta-hemolytic
Causative agent of many URIs and strep throat
Streptococcus pyogenes
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ID the bug:
Gram-pos cocci in pairs/chains
Catalase negative
Gamma-hemolytic
Group D Lancefield Streptococci
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ID the bug:
Gram-pos cocci in pairs/chains
Lancefield Group D antigen positive
Resistant to bile salts
Normal GI flora
Enterococcus species
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Gram positive rods can be divided based on what two criteria?
- Spore-forming vs non-spore forming
- Aerobic vs Anaerobic
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ID the bug, and where they can be found:
Gram-pos rod
Spore-forming
Aerobic
- Bacillus
- Found in soil and water
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ID the bug, and where they can be found:
Gram-pos rod
Spore-forming
Anaerobic
- Clostridium
- Found in soil, water, and human GI tract
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ID the bug:
Gram-positive rod (sometimes club-shaped)
Non-spore forming
Aerobic
Normal flora except one
- Corynebacterium
- Normal flora, except C. diptheriae
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ID the bug:
Gram-pos rod
Non-spore forming
Anaerobic
Normal flora of mouth, vagina, and GI
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ID the bug:
Gram-pos rod
Non-spore forming
Aerobic
Can grow as low as 4*C
Facultative intracellular
Exhibits tumbling motility
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ID the bug:
Gram-positive rod
- filamentous and branching
- can also stain partial acid-fast
Non-spore forming
Aerobic
Found in soil and water
Opportunistic
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ID the bug:
Gram-pos rod
- filamentous and branching
Normal flora
Anaerobic
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ID the bug:
Gram-neg cocci
Grown on chocolate agar in 5% CO2
Colonize mucosal surfaces
- associated with or in PMNs
Oxidase positive
- Neisseria spp
- mostly non-pathogenic
- two pathogenic species are N. gonorrhoeae and N. meningitidis
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How can you differentiate between N. meningitidis and N. gonorrhoeae?
- By the sugars they ferment:
- N. gonorrhoeae
only ferments glucose - N. meningitides ferments maltose and glucose
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ID the bug:
Gram-neg coccobacilli (actually bacillus)
Found in water and soil
Can colonize skin
Antibiotic resistant
Important nosocomial pathogen
Acinetobacter
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ID the bug:
Gram-neg coccobacilli (actually bacillus)
Normal upper respiratory flora
Cause of otitis media, bacteremia, meningitis, among others
Moraxella
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What are the two major groups/families of Gram neg rods?
- Enterobacteriaceae
- Non-enterobacteriaceae
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What are three properties common to all enterobacteriaceae?
- Glucose fermenters
- Oxidase negative
- Normal flora of human GI tract
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What two tests are used to differentiate enterobacteriaceae?
- Growth on MacConkey agar (tests lactose fermentation)
- Growth on Hektoen enteric agar, to test H2S production (differentiates non-lactose fermenters)
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What are the four main lactose-fermenting Gram-neg rods?
- Escherichia
- Klebsiella
- Serratia
- Enterobacter
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What are the four main non-lactose fermenting Gram-neg rods?
- Proteus
- Salmonella
- Shigella
- Yersina
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ID the bug:
Gram-neg rod
Ferments glucose and lactose
Oxidase negative
Normal flora, but can cause many infections, especially GI and UTIs
Escherichia
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ID the bug:
Gram-neg rod
Ferments glucose and lactose
Oxidase negative
Normal flora, but can cause pneumonia, UTI, GI, and others
Klebsiella
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ID the two bugs:
Gram-neg rod
Ferments glucose and lactose
Oxidase negative
Normal flora, but often cause infections in hospitalized patients
Serratia and Enterobacter
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