37. Microbiology Flashcards
shapes- spheres
coccus/cocci
rod shaped
bacillus/bacilli
slightly curved rod
Vibiro
vibrio gram negative or positive
gram negative
antibiotics for staph aureus
flucloxacillin IV
antibiotics for staph epidermis
Vancomycin IV
antibiotics for strep pyrogenes (GAS)
doxycycline
antibiotics for Gram negatives
clindamycin
flucloxacillin IV is for what infection
staph aureus
Vancomycin IV is the drug for what infection
staph epidermis
doxycycline is the drug for what infection
strep pyrogenes (GAS)
clindamycin is the drug for what infection
gram negatives
rigid spiral bacterium
spirillum
flexible spiral bacterium
spirochete
neisseria meningitidis and neisseria gonorrhoeae are examples of what
gram negative cocci
gram negative cocci associated with the GI tract are..
gut commensal gut coliforms (many are part of normal bowel flora)
If gut commensal coliforms get into sterile environments they can cause
UTIs
what if the first line antibiotic do you use to treat coliforms
Gentamicin
Only Streptococcus can be identified by
Haemolyisis
streptococcus is gram what
positive
GAS: numerous associated diseases such as and when haemolysis is tested it is
scarlet fever, impetigo, beta- haemolytic
streptococcus pneumoniae:
Haemolysis result?
What colour does it stain
pneumonia,
alpha-haemolytic
Green
Staphylococcus epidermis and Staphylococcus aureus. which is coagulase negative and which is coagulase positive
Staphylococcus epidermis is negative and Staphylococcus aureus is positive
give an example of where Staphylococcus epidermis is contracted
Nosocomial
staph epidermis is Nosocomial because it is associated with what devices
foreign devices such as catheters
give examples of where Staphylococcus aureus is contracted
community and nosocomial
Which gram positive pathogen appears golden
staph aureus
staph aureus forms what shape
clumps
skin, soft tissue and wound infections are most commonly caused by what pathogen (and sepsis)
gram positive staph aureus
enteric infections that are y-haemolytic are…
enterococcus
where is enterococcus found
normal bowel flora but it is a problem if it gats into sterile areas
what else is part of normal bowel flora that produces exotoxins which cause serious tissue damage
Clostridium spp.
give an example of a Clostridium spp.
Clostridium Difficile
what does Clostridium Difficile cause and when would it do this
antibiotic associated diarrhoea especially in elderly people and proliferates in the absence of normal bowel flora
Name the antibiotics that act on the bacterial cell wall
penicillin’s eg. flucloxacillin, amoxicillin
Cephalosporins eg. cefaclor, cefadroxil, cefalexin
Glycopeptides eg Vancomycin
describe the properties of Penicillins
beta lactam
few side effects
range from narrow to broad spectrum
excreted rapidly from kidneys
safe in pregnancy
people can be allergic
describe the properties of Cephalosporins
modified beta lactams
excreted via kidneys and urine
safe in pregnancy
describe the properties of glycopeptides
not absorbed when given orally (has to be IV)
side effects - damages kidneys and occasionally causes red man syndrome (allergy)
Name the antibiotics that inhibit protein synthesis
Macrolides eg erythromycin, azithromycin, clarithromycin
Aminoglycosides eg. gentamicin
clindamycin
Chloramphenicol
tetracyclines
which antibiotic is given to those with penicillin allergy
clindamycin or erythromycin
which antibiotic is given to those with topical eye infections
chloramphenicol
describe the properties of macrolides
excreted via liver, biliary tract and into the gut
lipophilic- easily pass through cell membranes
erythromycin is safe in pregnancy
describe the properties of aminoglycosides
must be IV
mainly active aginst gram -ve aerobic organisms
excreted in urine
side effects- kidney damage,deafness/dizziness
describe the properties of Clindamycin
2nd line against serious staphylococcal and streptococcus infection, especially in penicillin allergic patients
Name the antibiotics that act on bacterial dna
metronidazole
trimethoprim
Fluoroquinolones - ciprofloxacin, levofloxacin
describe the properties of metronidazole
oral and IV
breaks strands of dna
used for infections of true anaerobes and some by protozoa
interactions with alcohol
describe the properties of trimethoprim
inhibits bacterial folic acid synthesis
describe the properties of fluoroquinolones
bactericidal
use is severely restricted (risk of C.difficile)
only antibiotics that can be given orally for Pseudomonas
side effects - weakens tendons, joint damage in young kids, may cause seizures
interacts with topoisomerases - bacteria can no longer replicate
which antibiotics are mainly given to gram negative aerobic organisms
aminoglycosides such as gentamicin and clindamicin
what is used as a beta lactamase inhibitor especially if amoxicillin won’t cut it
co-amoxiclav
what are the 4 phases of bacterial growth in order
lag phase, exponential phase, stationary phase, decline phase
Describe the cell wall of Gram-positive bacteria:
thick layer of peptidoglycan in cell wall retains primary Gram stain (purple)
exotoxins
Describe the cell wall of Gram-negative bacteria:
thinner peptidoglycan layer, allows crystal violet to wash out and are stained by counterstain (pink)
endotoxins
LPS
which organisms are each haemolytic section? aka
Alpha - ?
Beta - ?
Gamma - ?
Strep Pneumoniae
Strep Pyogenes GAS
Enterococcus
name the 2 types of defensive structures of a bacteria
spore
capsule
what are capsules made of
polysaccharides
aerobes?
grow in O2
Obligate aerobes
require O2
facultative anaerobes
tolerate O2
Obligate anaerobes
killed by O2
Bacteria inside a biofilm are much more/less resistant to antimicrobial agents
more
Anaerobes treated with
metronidazole, cotriomazol
C diff. and the 4 Cs
- Co-amoxiclav, cephalosporins, clindamycin, ciprofloxin
- Broad spectrum agents alter nomal gut flora
- Clostridioides difficile (CDI) proliferates → causes diarrhoea and spreads
- Avoid if possible
carbapenem - Betalactam or no
yes
