MicroB intro Flashcards
Staphlococcus aureus
Genus- Staphlococcus
Species- aureus
Bacterial genome type
- circular DNA
- plasmids
- -/+ RNA
Prokaryotic nature of bacteria
- no nuclear membrane
- no mitochondria
- micrometre range
3 ways of transfer of DNA in bacteria
- Conjugation (plasmid mediated)
- Transduction (bacteriophage)
- Transformation (free DNA picked up from env.)
What are the antibiotic resistance genes?
- NDM-1: enzyme against carbapenems
- TEM: ag penicillins
- MCR-1: colistin
- toxins also confer resistance
What are the bacteria surface components?
- LPS endotoxin – outer membrane of gram -ve bact
* as +ve no outer member - fimbriae/pili: adherence fn
- flagella: move
- capsules: protect from immune response
- most bact contain peptidoglycan
Some bacteria no cell wall. Give an example.
Mycoplasma– atypicals
hence cannot use cell wall synthesis inhibitors (except 5th gen cephalosporins)
Which bacteria forms spores?
Bacillus spp, Clostridium spp.
What are fungi?
eukaryotes,
2 forms- hyphal (mould), yeast
airborne spores
What are protozoas & helminths?
protozoa- unicellular eukaryote (amoeba, flagellates, apicomplexans)
vs helminths- multicellular eukaryote (nematodes, trematodes, cestodes)
What are prions?
- no DNA/RNA, no cells, not living
- just proteins
- abnormal 3D conf of normal protein, resistant to degradation by heat–> cellular malfn
eg CJD, BSE, Scrapie (sheep)
How do gram +ve & -ve look different under gram stain?
- +ve dark blue
2. -ve red
What cannot be seen under gram stain?
- TB ziehl-neelsen or auramine fluorescent stain
- trepnoema pallidum (syphilis)- dark ground illumination
- mycoplasma
What does a clone of bacteria appear as on solid media agar?
single colony
