Gram Positive Bacteria Flashcards
Staphylococcus aureus
Gram positive
Aerobic
Staphylococci
Coagulase positive
Commensal bacteria of the nose, axilla, perineum
Major human pathogen
Wide range of symptoms from soft tissue infection to septicaemia
Commonly penicillin resistant
MRSA is methicillin resistant
Staphylococcus epidermidis
Gram positive
Aerobic
Staphylococci
Coagulase negative
Can cause UTI’s
Can form biofilms
Can colonise prosthetics such as joint replacements and valve replacements and catheters
Staphylococcus lugdunesis
Gram positive
Aerobic
Staphylococci
Coagulase negative
Behaves like staphylococcus aureus
Staph. haemolyiticus and staph. saprophyticus
Gram positive
Aerobic
Staphylococci
Coagulase negative
Alpha haemolytic
Partial haemolysis, turns blood agar green
Beta haemolytic
Complete haemolysis, turns blood agar clear
Non haemolytic
No haemolysis, no difference in blood agar colour
Streptococcus pneumoiae
Gram positive
Aerobic
Streptococcus
Alpha haemolytic
Can cause pneumonia, meningitis, septicaemia
Streptococcus viridans
Gram positive
Aerobic
Streptococcus
Alpha haemolytic
Many different species
Typically colonise the oral cavity
How do we further classify beta haemolytic streptococci?
By their surface antigens - which is called a Lancefield group
There are 7 groups, A-G
Most clinically important streptococcus Lancefield groups
Groups A, B, F and D
Streptococcus pyogenes (group A streptococcus)
Gram positive
Aerobic
Streptococcus
Beta haemolytic
Group A
Can cause pharyngitis, cellulitis, necrotising fasciitis
Streptococcus agalactiae (group B streptococcus)
Gram positive
Aerobic
Streptococcus
Beta haemolytic
Group B
Typically causes infection in neonates and older adults
Can cause meningitis
Enterococcus spp.
Gram positive
Aerobic
Streptococcus
Often non-haemolytic
Commensal of gut
Can cause UTI and infective endocarditis
Clostridiodes difficile
Gram positive
Anaerobic
Bacilli
Difficult to culture
Normal commensal of the gut
Can cause diarrhoea and produce toxins
Spread through spores
