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Flashcards in Classification of medically important organisms Deck (37):

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?



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



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