Classification of medically important organisms Flashcards
how do you write the genus and the species?
the Genus is in capital letter, species is lowercase, and all is italic
what colour is gram positive bacteria?
purple
the bacteria genus, Bacillus, how would you describe them?
they are gram positive, they are rod shaped, live everywhere - air, soil, water, they’re quite large compared to other bacteria. they are aerobes and they form spores.
why are spores needed in Bacillus?
they are important in terms of survival. when the food isnt good / temp isnt suitable, then these bacteria will sporillate and become inactive but still alive
give examples of Bacillus bacteria and what they cause
B. anthracis - causes anthrax
B. stearothermophilus - highly resistant to heat
B. cereus - food poisoning bacteria
name some genus of gram positive rod shaped bacteria
Bacillus, clostridium, listeria
describe the gram positive rod shaped bacteria, Clostridium
it lives in soil and water and is anaerobic, it forms spores, produce gas (they stink)
examples of clostridium bacteria and what they cause
C. perfringens - causes gas gangrene
C. tetani - causes tetanus
C. botulinum - serious food poisoning, used to produce botox
where do Listeria grow?
they are common in the environment, can grow at fridge temp
what is the main species of Listeria? and what does it cause?
L. monocytogenes - it causes listeriosis (Rare), it can cross the placenta, can cause spontaneous abortion
which 2 gram positive bacteria form spores?
Bacillius and Clostridium
describe Corynebacterium
they are gram poisitive, irregular shaped rods, they live in the air, water and skin, they are aerobic
give 2 examples of corynebacterium and what they are used for
C. glutamicum, - used to make glutamic acid (MSG).
C. diphtheriae - causes diphtheria, produce exotoxins
give examples of gram positive cocci genus
staphylococcus, pseudomonas, streptococcus
describe staphylococcus
they are gram positive, cocci shaped bacteria. they live in the air, soil, skin, it is a facultative anaerobe and an opportunistic pathogen
give examples of staphylococcus bacteria and what they cause
S. aureus - causes boils , TSS, endocarditis, antibiotic resistance
- S. epidermidis - medical device infection
describe streptococcus
they live in air, soil and the throat
they are a facultative anaerobe
- opportunistic pathogen
give examples of streptococcus bacteria and what they cause
S. pneumoniae - can cause bacterial pneumonia, produces a capsule
S.pyogenes - causes sore throats and scarlet fever
give examples of gram negative bacteria genus
Pseudomonas, escherichia, neisseria
describe Pseudomonas
it is a gram negative rod, it is ubiquitous, aerobe, opportunistic pathogen, antibiotic resistant bc of the slime, biochemically versatile - can metabolisme many different things,
they produce slime
give examples of 2 gram negative rod shaped genus bacteria
Pseudomonas, escherichia
give examples of a gram negative cocci shaped genus bacteria
neisseria
give an example of Pseudomonas bacteria and what does it cause
P. aeruginosa, causes 50% of gram negative infections, cystic fibrosis, conjunctivitis, contact lens contamination, secondary infection of wounds, burns etc
describe Escherichia
it’s E.coli, comes only from our gut, can survive in soil, water and vegetation.
it is a facultative aerobe, its enteric
where does E.coli come from/?
strictly only our gut
what does enteric mean?
it lives in the gut
give an example of Escherichia
E.coli - some strains are pathogens, causes 80% of UTIs, infant enteritis and cystitis
describe Neisseria
a gram negative cocci shaped bacteria
they live in throats and air
facultative anaerobe
diplococci - hang around in pairs
give example of Neisseria and what they cause
N.meningitidis - causes bacterial meningitis which has a 100% mortality rate if untreated and less than 15% mortality rate if treated .
-N. gonorrhoeae, causes gonnoria and it has to live in humans, cant live in soil
which bacteria are neither gram positive or gram negative?
Mycoplasmas and mycobacteria, and the obligate intracellular bacteria, they HAVE to live inside cells - difficult to grow in lab
what is the structure of mycoplasmas?
they are the smallest free living organisms, they have no cell wall therefore they cant be gram stained, they have a very small genome
why cant mycoplasmas be gram stained?
they have no cell wall
give 2 examples of mycoplasmas
M.pneumoniae, M.genitalium
features of mycobacteria:
very slow growing - takes 12 days, this is bc it has very unusual cell wall structure - waxy due to mycolic acid, can be stained using Ziel-Nielson stain
give 2 examples of mycobacteria:
M.tuberculosis, M.leprae
list some obligately intracellular bacteria and what do they cause?
- Chlamydia eg C.trachomatis causes pelvic inflammatory disease, linked to ectopic pregnancy (grow outside the body)
2. Rickettsia - causes typhus spread by arthropods.
3.Coxiella - causes Q fever
how can you go grow obligately intracellular bacteria in the lab?
must be cultivated in living tissue, this hinders research
