Antibiotics Flashcards
Name the antibiotics that effect cell wall synthesis? Folate synthesis? Nucleic acid synthesis? Protein synthesis?
cell wall synthesis: beta lactams - Penicillins, cephalosporins, carbapenems, monobactam; glycopeptides - vancomycin, teicoplanin; polymyxins - colistin
Folate synthesis: Sulfamethoxazole, trimethoprim
Nucleic acid synthesis: DNA Synthesis - Fluoruquinolones, metronidazole; RNA polymerase - rifamycins
Protein synthesis: 30S subunit - Aminoglycosides, tetracyclines; 50s subunit - macrolides, clindamycin, linezolid, chloramphenicol, Fusidic acid
antibiotics in co-amxiclav?
amoxicillin and clavulanic acid
antibiotics in tazocin?
piperacillin and tazobactam
Cephalosporin structure?
Contain a beta-lactam ring attached to a six-membered nuclear structure
(five in penicillin) - allows synthetic modifi cation at two sites (one in penicillin) - therefore the largest group of available antibiotics
Which is the broadest spectrum beta lactam antibiotic?
Carbapenums
Which bacteria is Aztreonam active against? SEs? Class?
Monobactam
only active against Gram-negative species including Neisseria meningitidis,
Haemophilus influenzae, Pseudomonas. Given IV/IM. Inhaled preparation
for chronic pulmonary Pseudomonas (cystic fibrosis)
SEs: N&V, GI bleed, rash, raised LFTS, reduced plts, paraesthesia, seizures, bronchospasm.
Which are the non-beta lactam cell wall inhibitors?
Includes glycopeptides, eg vancomycin, teicoplanin, and
polymyxins, eg colistin
Nitrofurantoin MOA? uses? SEs?
Metabolites interfere with cell growth via ribosomes, DNA,
RNA, and cell wall. Multiple sites of attack means reduced resistance used in uncomplicated UTI
SES: haemolysis, pulmonary fibrosis,
hepatotoxicity
Name 6 penicillins
Penicillin G (benzylpenicillin), Penicillin V (Phenoxymethylpenicillin), amoxicillin/ampicillin (amoxicillin PO, ampicillin IV), Co-amoxiclax, Piperacillin+tazobactam, flucloxacillin
Benzylpencillin indiciations? route? SE?
Gram +ve: streptococci (chest, throat, endocarditis, cellulitis),
meningococcus, diphtheria, anthrax,
leptospirosis, Lyme disease
IV
SE: allergy,rash, N+V, C.diff, cholestasis
Penicillin V indications?
Prophylaxis: splenectomy/hyposplenism,
rheumatic heart disease
Ampicillin/amoxicillin MOA? indications? route? SE?
Amino acid side chain extends
penicillin spectrum to include enterobacteria
URTI, sinusitis, chest, otitis media, UTI, H. pylori
SE: as per penicillin G, rash with EBV.
Co-amoxiclav indications?
Used if resistance to narrower spectrum
antibiotics: chest,
pyelonephritis, cellulitis, bone
Piperacillin+tazobactam Indications? properties? SE?
Broad spectrum including Gram
+ve, Gram -ve, Pseudomonas:
neutropenic sepsis, hospitalacquired/
complicated infection.
Tazobactam has reduced penetration of blood brain barrier
SE: SE: as per penicillin G.
Myelosuppression with prolonged use (rare).
Flucloxacillin indications? SE?
beta-lactamase resistant, Staphylococcus:
skin, bone, post-viral
pneumonia.
SE: allergy, rash, N+V, cholestasis
Name the 1st, 2nd and 3rd generation cephalosporins
1st: Cefalexin
2nd: Cefuroxime,
3rd: Cefotaxime, ceftriaxone, ceftazidime
Cephalosporins SE? Caution? (4)
Reduced first line use in UK due to risk of C.diff
Caution: false +ve
urinary glucose and
Coomb’s test
SE: allergy, rash,
N&V, cholestasis.
Ceftriaxone can
precipitate in urinary
tract and biliary tree =
pseudolithiasis.
Indications of cefalexin?
Gram +ve infection: UTI, pneumonia
Cefuroxime indications?
Gram +ve and Gram -ve (Enterobacteriaceae,
H. influenzae): UTI, sinusitis, skin, wound.
cefotaxime indications?
Broad spectrum (not Pseudomonas, Enterococcus spp, Bacteroides).
Ceftriaxone indications? SE?
Meningococcus. Broad spectrum (not Pseudomonas, Enterococcus spp, Bacteroides Ceftriaxone can precipitate in urinary tract and biliary tree = pseudolithiasis.
Ceftazidime indications?
Broad spectrum including Pseudomonas but
reduced activity against Gram +ve: empirical treatment
of neutropenic sepsis.
Name 3 carbapenems? SEs?
Imipenum (Imipenem
given with cilastatin to reduce renal
metabolism), meropenum, ertapenum
SE: N&V, C. difficile, rash, eosinophilia,
reduced plts, raised LFTs, seizures.
Name two lipopeptides and two polmyxins
lipopeptides: vancomycin, teicoplanin
polymyxins: colistin, polymyxin B
Lipopeptides indications? SEs? Monitoring?
Complicated Gram +ve
including MRSA. Oral for C.difficile (not absorbed).
SEs:
nephrotoxic (monitor creatinine, care with
other nephrotoxics) ototoxic, reduced plts.
monitor creatinine
polymyxins indication? consideration?
nephrotoxicity occurs in 50%
Inhaled colistin for ventilator-associated pneumonia
Name the antibiotics that inhibit protein synthesis?
Protein synthesis: 30S subunit - Aminoglycosides, tetracyclines; 50s subunit - macrolides, clindamycin, linezolid, chloramphenicol, Fusidic acid
Name 3 aminoglycosides. Indications? SEs? Monitoring?
Gentamicin, tobramycin, amikacin
Gram Ωve infection (reduced activity against most Gram +ve and anaerobes). Tobramycin has
increased activity against Pseudomonas.
Amikacin has least resistance.
SEs: nephrotoxic (monitor drug
levels and serum creatinine),
vestibular toxicity, ototoxicity.
Name 3 macrolides, indications, SEs?
Azithromycin, Clarithromyin, erythromycin
Gram +ve cocci (not enterococci and staphylococci), syphilis, chlamydia.
SEs (increased with erythromycin): GI, cholestasis, prolonged QT. Cytochrome P450 inhibition (reduced with azithromycin): increased warfarin, rhabdomyolysis with statins, increased calcineurin inhibitor levels.
Name three tetracyclines? Indications? CI? SE?
tetracycline, doxycycline and tigecycline
Exacerbation COPD, chlamydia, Lyme disease, mycoplasma, rickettsiae, brucella, anthrax, syphilis,
MRSA, malaria prophylaxis.
CI: pregnancy, <8yr (permanently stain teeth)
SEs:N&V, C. difficile, fatty liver, idiopathic intracranial hypertension.
tigecycline is used for Gram +ve and Gram -ve including
beta-lactam-resistant strains.
SEs: N&V, photosensitivity, raised LFTs.
Clindamycin indications? SEs?
Gram +ve cocci (not enterococci),
MRSA, anaerobes
Linezolid indications?
Gram +ve cocci, MRSA, VRE, anaerobes, mycobacteria
Its a weak monoamine oxidase inhibitor (check interactions) -
myelosuppression,
optic neuropathy.
Chloramphenicol indications? considerations?
Gram +ve, Gram Ωve, anaerobes, mycoplasma, chlamydia, conjunctivitis
(topical).
Systemic use limited by myelosuppression
Fusidic acid indication? SEs?
Staphylococci.
SES: GI, raised LFTs.
Coagulase negative vs positive staphylococci examples? virulence?
Coagulase-negative staphylococci - Staph epidermidis
positive - staph aureus
coagulase negative is less virulent - pathogenicity only likely if underlying immune system dysfunction or foreign material (prosthetic valve/joint, IV line, PD catheter, pacemaker)
Different presentations of coagulase positive staphylococcus?
- Toxin release causes disease distant from infection. Includes: Scalded skin syndrome (bullae and desquamation due to epidermolytic toxins
(no mucosal disease, less skin loss compared to toxic epidermal necrolysis)
preformed toxin in food - sudden D+V
toxic shock: fever, confusion, rash, diarrhoea, low BP, AKI, multiorgan dysfunction.
Tampon associated or occurs with (minor) local infection. - Local tissue destruction: impetigo, cellulitis, mastitis, septic arthritis, osteomyelitis,
abscess, pneumonia, UTI. - Haematogenous spread: bacteraemia, endocarditis, ‘metastatic’ seeding.
Symptoms of toxic shock? Causative organism
fever, confusion, rash, diarrhoea, low BP, AKI, multiorgan dysfunction.
coagulase positive staph
How is staph aureus resistance defined?
by stability to
meticillin, ie meticillin-resistant Staph. aureus (MRSA)
How is vancomycin resistance classified in staph aureus?
classified according to the amount of vancomycin needed to inhibit
bacterial growth: vancomycin-intermediate Staph. aureus (VISA) and vancomycin-
resistant Staph. aureus (VRSA).
Risk factors for MRSA colonisation?
antibiotic exposure, hospital stay, surgery, nursing home residence.
MRSA infection treatment?
vancomycin (for MRSA), teicoplanin
oral agents with activity against MRSE?
clindamycin, co-trimoxazole, doxycycline, linezolid
What are the major classes of gram positive cocci?
staphylococci
streptococci
enterococci
