gram positive bacteria Flashcards
what are the two main categories of gram positive bacteria?
Cocci and bacilli
How can bacilli be further categorised?
Aerobic and anaerobic
How can aerobic bacilli be further categorised?
spore forming, or non spore forming
are anaerobic bacilli spore forming or non spore forming?
Spore forming
how can cocci be further categorised?
Staphylococci
streptococci
what is the appearance of staphylococci and streptococci?
Staphylococci - clusters
Streptococci - chains
How can staphylococci be further categorised?
coagulase test - positive or negative
How can streptococci be further categorised?
haemolysis - partial - a
complete - b
none
how do partial and complete haemolysis affect blood agar?
partial - turns green
complete - turns clear
How can Streptococci - complete haemolysis be further categorised?
They can be grouped by lance field grouping - which is based on surface antigens.
Name two spore forming, bacilli, aerobic positive bacteria.
listeria monocytogenes
Corynebacterium diphtheria
what species are non spore forming, aerobic bacilli?
Bacillus species
what species are ANaerobic, and spore forming?
clostridium species
name three bacteria within clostridium species
clostridium difficile
clostridium perfringens
clostridium tetani
What does clostridium tetani cause?
tetanus - uncontrollable muscle spasms
where is clostridium perfringens found as a normal commensal, and where else is it found?
commensal in human and animal gut and faeces.
also found in soil
what can clostridium difficile cause?
dihorea associated with toxin production.
can be carried asymptomatically
what can clostridium perfringens cause?
food poisoning or ‘gas gangrene’ in wounds
When are you at an increased risk of developing clostridium difficile?
when your taking antibiotics.
How can clostridium difficile be detected?
in a Stool sample using ELISA
What bacteria tests positive from the coagulase test?
Staphylococcus aureas
Name two bacteria which test negative from coagulase test?
staph. epidermis
staph. saprophyticus
where are the two negative coagulase bacteria found as commensals?
skin
when are staph. epidermis and staph. saprophyticus pathogenic?
In the presence of foreign bodies. e.g. heart valves / hip replacements
staphylococcus aureas can be MSSA or MRSA. what does this mean?
can be methicillin resistant or methicillin sensitive.
the resistant one is a problem for infection control in hospitals.
Why can staphylococcus aureas be penicillin resistant?
due to B - lactamase
Where is staphylococcus aureas a commensal and what does it do when its pathogenic?
commensal in nose, groin, hairline.
causes lots of diseases, from boils to septicaemia.
what bacteria turns blood agar green?
viridans streptococci
strep. pneumoniae
what does viridans streptococci cause and where does it occur commensally?
infection of heart valves (endocarditis)
normal oral fauna
what does strep. pneumoniae cause?
septicaemia, pneumonia, meningitis
name a bacteria in group B lance fielding group. a haemolysis streptococci.
Streptococcus agalactiae.
what does streptococcus agalactiae cause?
Neonatal sepsis - meningitis, bacteraemia.
it is carried in the genital tract.
Name A group a lance field group bacteria
strep. pyogenes.
What does strep pyogenes cause?
Sore throat, cellulitis, necrotising fasciitis.
Non - haemolytic streptococci are group D. Name a species
Enterococcus sp.
Name 2 types of enterococcus species.
Enterococcus faecalis
Enterococcus faecium
Where are enterococcus species found and what harm do they cause?
found in gut
cause UTIS
