Antibiotics, Antivirals & Antifungals Flashcards
Amoxicillin active against
gram positive
macrolides active against
gram positive - e.g erythromycin
cell wall inhibitors
FAPP CCTV
Flucloxacillin amoxacillin penicillin piperacillin cephalosprins carbapenams teicoplanin (glycopeptide) vancomycin (glycopeptide)
Protein synthesis inhibitors
COMAT
chloramphenicol oxazolidinones - linezolid Macrolides - erythromycin Aminoglycosides - gent Tetracyclines (cant use in kids)
Inhibitors of DNA synthesis
F -aNaerobes
Fluoroquinolones (gram neg)
Nitroamidazoles - anaerobes
Inhibitors of RNA synthesis
Rifamycins
cell membrane toxins
polymixins - colistin
cyclic lipopeptides - daptomycin
inhibit folate metabolism
sulphonamides
diaminopyrimidines
cant use in first trimester due to fears of neural tube defects
do all
nitrofurans
an antiviral which can be used in aerosol form to prevent respiratory syncytial virus in children with heart and lung disease
ribavirin
What drug is used to prevent verticle transmission of HIV during pregnancy
Normal ART for the pregnant woman whether she was on treatment beforehand or not.
Viral load should be tested at 36 weeks.
If viral load is below 50 vaginal birth may continue and the baby should be given zidovudine for 4-6 weeks.
if viral load is above 50, c section with 4 hour previous zidovudine infusion, and baby recieves triple therapy for 4-6 weeks
Tretment for influenza
oseltamivir
describe the metabolism of acyclovir
uses viral thymidine kinase to make monophosphate, then cells enzymes to di and tri phosphate which is the active compnent and inhibits viral DNA polymerase
CMV treatment
ganciclovir
PERCH - owls eyes inclusions
Pneumonitis Encephalitis Retinitis Colitis Hepatitis
CMV symptoms and treatment
ganciclovir
PERCH - owls eyes inclusions
Pneumonitis Encephalitis Retinitis Colitis Hepatitis
valacyclovir uses
HSV VZV
A drug that is effective against influenza A but not influenza B
amantadine
Treatment for resistant or sever HSV
foscarnet or cidofovir
The drug which can be delivered by inhalation to treat both influenza A and B.
Zanamivir - neuraminidase inhibitor
Treatment of an 18 year old with Meningitis.
ceftriaxone
A 12 yr old boy requests treatment for widespread impetigo. He developed an urticarial rash 3 yrs ago when he was given penicillin V
erythromycin
Patient with an abdominal collection that contains gram –ve anaerobes.
metronidazole
56 year old male with endocarditis caused by VRE.
linezolid - is an oxazolidinone and is used in Vancomysin resistant enterococcus and MRSA positive. s primarily active against gram +ve
Severe systemic infection before cause has been identified
cefuroxime
legionella treatment
erythromycin - although macrolides typically have a gram positive action, they are first line in treating legionaires. fluoroquinolones are also useful.
treatment for sepsis, sever CAP, or HAP
cefuroxime -
may add clarythromycin to sever CAP
may add met and gent to severe sepsis
optochin sensitive and alpha haemolytic
strep pneumon. (viridans is also alpha haemolytic but optochin resistant)
what are tetracyclines good for?
intracellular pathogens
Name 5 classes of antifungal
PATFE Polyenes Azoles Turbinofene Flucytosine Echinocandin
Name a polyene and their mechanism of action
Amphoteracin targets cell membrane integrity
Name yeast targetting antifungals
amphoteracin
fluconazole
caspofungin
name an echinocandin
caspofungin
name an azole
fluconazole or ketoconazole
name mould targetting antifungals
terbinafine - dermatophyte infections
what does flucytosine target
DNA synthesis
which antifungal do you use to treat cryptococcal meningitis
amphotericin
What colour is gram negative
pink
what colour is gramm positive
purple - staining of the thick peptidoglycan layer
what bacteria does not show up on gramm stain
mycoplasma
Antibiotics which are concentration dependent
Aminoglycosides - dependant on the height of the peak to kill. often given once per day and then trough level measured. dose delayed if trough is too high. if peak is not high enough change the dose.
describe the action of the cephalosporins
Cell wall inhibitors with an increasing action on gram negatives as the generations progress. Designed to be stable against beta lactamases. however now there are extended spectrum beta lactamases to break this down. (enzymatic inactivation)
1st GEn Cephalexin
2nd gen Cefuroxime
3rd gen Cefotaxime, Ceftriaxone. Ceftazidine
Ceftazidime - has antipseudomonal activity but no gram positive
What are the beta lactams and what do they do
include penicillins, cephalosporins and carbapenams and monobactams. inhibit transpeptidase actions and only act on dividing bacteria(eagle effect) . This makes them inactive in scenarios like sequestred osteomyelitis. grandaughter cells are what break.
what is penicillin active against
typically streptococci and clostridia, but broken down by the beta lactamases in staph. - use fluclox.
what is amoxicillin active against
broad spectrum extending to enterococcus and other negatives. Many are resistant and so adding clavulanic acid makes it stable to these.
what is the profile of flucloxacillin.
gram positive similar to penicillin except is stable to beta lactamase produced by staph aureus.
Staph aureus is now showing resistance to this (MRSA) by altering the binding site
What is the profile of pipericillin.
Similar to amoxillin but with additional pseudomonal coverage. broken down by beta lactamases so is added to tazobactam
What is the main difference between the efficacy of amoxicillin and cephalosporins?
ceph has less activity against anaerobes and so is often added to a nitroamidazole.
C dif is associated with which drugs in particular?
ceftriaxone
co-amoxyclav
What is the action of carbapenams? Name 3.
designed to treat ESBLs.
meropenam
imipenam
ertapenem
name 2 common carbapenamases
Klebsiella and acinetobacter
why are glycopeptides useless against gram negatives?
Very large molecule that cant penetrate the outer membrane of gram negatives.
What unit do aminoglycosides work at?
30s ribosomal subunit
What is the activity of aminoglycosides? Name 3.
Are broad spectrum, but they have no activity against anaerobes. They do have good anti pseudomonal properties though.
Gentamicin
Amikacin
Tobramycin
why dont antibiotics work in abcesses
dont work very well at a low PH. aminoglycosides particularly
What is the profile of tetracyclines? what is their down side?
Have broad spectrum activity but particularly effective against intracellular pathogens.
There is wide resistance and its action is only bacteriostatic.
they often cuase a light sentive rash and cannot be used in children due to bone staining.
Protein synthesis inhibitors: macrolides, tetracyclines, and chloramphenicol are what?
bacteriostatic
What is the profile of macrolides?
act on the 50s subunit
Their action is against gram positives, however clarythromycin and azithromycin have some negative action.
Ertyhromycin is only positive
They are good at treating intracellular pathogens such as campylobacter and legionella.
What are the main uses of chloramphenicol?
Eye drops and Meningitis in cephalosporin anaphylactics.
Binds to the 50s subunit also.
What are the side effects of chloramphenicol?
Can cause aplastic anaemia and grey baby syndrome.
What is the use of oxazalidenones?
Linezolid - used for Vancomycin resistant enterococcus and MRSA. they have good action against gram positives.
They can cause optic neuritis and thrombocytopenia.
What is the action of fluoroquinolones? Name 3.
Ciprofloxacin (broad)
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Levofloxacin (minimal -ve activity)
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Moxifloxacin (positive only)
They inhibit DNA gyrase. They have some use in UTI and now pneumonias to to increased grmm positive activity.
They have no effect against anaerobes.
What are nitroamidzoles active aginst?
strict anaerobes only by breaking down bacteria DNA.
What are the rifamycins used for?
Mycobacteria and chlamydiae.
Dna dependant RNA polymerase - inhibiting initiation of protein synthesis.
Side effects include interfering with INR, and turns secretions orange.
What is daptomycin used for? what is its pitfall?
treating MRSA and VRE with few other treatment options.
It is broken down by surfactant so cannot be used in respiratory disease.
What is collistin used for?
Active against gram negatives. is nephrotoxic and used fro drug resitant negatives such as pseudomonas, acinetobacter, klebsiella.
co-trimoxzalole use?
PCP pneumonia.
trimethoprim - UTI against staph and e.coli.
Has haem side effects
What are the 4 mechanisms of resistance to antibiotics?
BEAT
Bypass step
Enzymatic deactivation
Accumulation of antibiotic reduced
Target site alteration
Exapmle of enzymeatic inactivation
beta lactamases - beta lactams
Example of target site alteration
mecA gene involves a change in the PBP recepter (2a)
requires lethal concentrations of beta lactam
shown in strep pneumoniae
Where do beta lactams not penetrate?
csf
By what mechanism are ESBL’s resistant to cephalosporins?
Enzymatic inactivation.
What drugs have concentration dependant action?
aminoglycosides - gent, amikacin, tobramycin
Measure trough level to ensure being removed, and not giving too frequently.
Measure the peak to ensure high enough to kill. can adjust dose
What drugs are dependant on their time spent above the minimum inhibitory concentration.
penicillins. erythromycin
What drugs require an area under the curve? time AND concentration effects?
Vancomycin, azithromycin
How long should treatment last in endocarditis
4-6 weeks
how long should the treatment last in osteomyelitis
6 weeks
group A strep pharyngitis treatment length
10 days - ben pen - rheumatic fever and glomerulonephritis
When is IVig used?
big severe infection where debridement is necessary
What antibiotic should be added if listeria is suspected, and in what demographics i this used?
amoxicillin
very young under 3 months, or old over 65 or pregnant.
