ANTIBIOTIC SUMMARY Flashcards
What classes of Abx act on cell wall synthesis?
B-lactams Glycopeptides Bacitracin Cycloserine Fosfomycin
What classes of Abx act on the cell membrane?
Polymyxins
Lipopeptides
What classes of Abx act on nucleic acids?
Sulphonamides Quinolones Rifamycins Nitromidazoles Nitrofurantoin
What classes of Abx act on protein synthesis?
Aminoglycosides Oxazolidinone Chloramphenicol Tetracyclines MAcrolides Lincosamides Streptogramins Fusidic acid
Name some B-lactams
Pen G Pen V Cephalosporins Carbapenems Monobactams
What is the MoA of B-lactams?
Binds PBP preventing Xlinking of PG chain.
Incorporated into chain.
Stimulates autolysins
What is the MoR of B-lactams?
B-lactamases
Altered PBP
Mutations in porins
What are B-lactams used for?
Throat infections Endocarditis Meningitis Pneumonia Cellulitis Osteomyelitis
What are the side effects of B-lactams?
Hypersensitivity Neurotoxicity Renal failure Diarrhoea Pseudomonas colitis
Name some glycopeptides
Vancomycin
Teicoplanin
What is the MoA for glycopeptides?
Binds d-ala-d-ala.
Inhibits transglycosidase enzymes-PG nit incorporated
Inhibits X-linking
What is the MoR to glycopeptides?
D-ala-d-ala chages fo d-ala-dlactae/serine
Destabilises binding of vanc
What are glycopeptides used for?
C.diff infections
What are the side effects of glycopeptides?
Pain & thrombophlebitis Renal toxicity Ototoxicity Blood disorders Anaphylactoid reactions
What is the MoA of bacitracin?
Inhibits dephosphorylation of lipid carrier molecules.
Prevents transport of PG from cytoplasm to exterior of cell wall.
Cell lysis
What is MOR to bacitracin?
Increased phosphorylated lipid carrier
Efflux pumps
What is bacitracin used for?
Topically in combo with other abxs to prevent skin, eye and wound infections
What are the side effects of bacitracin?
Contact allergic dermatitis
What is the MoA of cycloserine?
Prevents formation of D-ala-d-ala through activation of 2 enzymes converting L-ala to D-ala
What is the MoR to cycloserine?
Overexpression of 1 converting enzymes
What is cycloserine used for?
TB
What are the side effects of cycloserine?
CNS
Rashes
Liver damage
What is the MoA of fosfomycin?
Inhibits enzyme NAG-enolpyruvate transferase
What is the MoR to Fosfomycin?
Plasmid and chromosomally encoded enzymes break open the epoxide ring of fosfomycin
Name some polymyxins
Polymyxin E (colistin) Polymycin B
What is the MoA of Polymyxins?
Out membrane: bind tightly to lipid A component of LPS. Membrane becomes distorted & destroyed.
Then penetrates PG layer and binds to phospholipids in cytoplasmic membrane causing leakage of cytoplasmic components
What is the MoR to polymyxins?
Change structure of Lipid A.
Loss of LPS
Due to chromosomal mutations or plasmid acquisition
What are the uses for polymyxins?
IV-systemic resistant G-ve infections
P.aeruginosa in CF
What are the side effects of polymyxins?
Neurotoxic
Nephrotoxic
Name a lipopeptide
Daptomycin
What is the MoA of lipopeptides?
Forms pores in cytoplasmic membrane through Ca dependent depolarisation. Efflux of K+ Decrease nutrient uptake Decrease ATP synthesis Decrease DNA, RNA and protein synthesis
What is the MoR to lipopeptides?
Rare
Alteration in cell membrane
What are lipopeptides used for?
IV-skin and soft tissue infections
Endocarditis caused by G+ve
What are the side effects of lipopeptides?
Nephrotoxicity
Myopathy
Peripheral neurotoxicity
Colitis
Name a sulphonamide
Trimethoprim
What is the MoA of sulphonamides?
Inhibits enzymes required for synthesis of tetrahydrofolic acid
What is the MoR to sulphonamides?
Plasmid encoded altered dihydropterate synthetase.
What is the MoR to trimethoprim?
Over production of dihydrofolate reductase
What are sulphonamides used for?
UTI
Acne
What are the side effects of sulphonamides?
GIT
Allergy
Myelosuppression
Name some quinolones
Ciprofloxacin
Levofloxacin
Moxifloxacin
Ofloxacin
What is the MoA of quinolones?
Inhibit DNA gyrase and topoisomerase IV
What is the MoR to quinolones?
Mutations in gyrase and top IV
Changes in efflux
Altered permeability
What are quinolones used for?
RTI UTI GIT STD Systemic G-ve
What are the side effects of quinolones?
GIT CNS Cartilage dev Tendon damage Rash Photosensitivity Renal impairment
Name a rifamycin
Rifampicin
What is the MoA of rifamycins?
Inhibit RNA polymerase
What is the MoR to rifamycins?
Mutations in RNA polymerase
Altered Efflux
What are rifamycins used for?
TB
Prophylactic meningitis
Prosthetic joint infections
Endocarditis caused by staph
What are the side effects of rifamycins?
Hepatotoxicity Fever Rash Hypersensitivity GIT Orange-red secretions
Name a nitroimidazole
Metronidazole
What is the MoA of nitroimidazoles?
Anaerobic conditions: nitroreductase and oxidoreductase form anion radicals.
Loss of function of DNA
Cell death
What is the MoR of nitroimidazoles?
Mutations in nitroreductases/oxidoreductase
What are nitroimidazoles used for?
C.diff
Genital tract infections
SSTIs-anaerobes
Abdominal and dental infections
What are the side effects of nitroimidazoles?
GIT
CNS
Hypersensitivity
Urine red/brown
What is the MoA of nitrofurantoin?
Oxidoreductase enzyes leads to ROS and DNA damage
What are the MoR to nitrofurantoin?
Mutations in nitroreductase/oxidoreductase
What is nitrofurantoin used for?
Non catheterised UTI
Name some aminoglycosides
Gentamicin
Amikamicin
Tobramycin
Streptomycin
What is the MoA of aminoglycosides?
Bind A site on 16s rRNA on 30S subunit.
Affect binding of tRNA in acceptor site.
Reduce translocation from A to P site
What is the MoR to aminoglycosides?
Enzymatic modification prevents binding with target
Adenylylase
Acetylase
Phosphorylase
What are aminoglycosides used for?
Septicaemia Complicated UTI Nosocomial RTI IV-serious aerobic baceria G-ve pseudomonas Some G+ve staph
What are the side effects of aminoglycosides?
Nephrotoxicity
Ototoxicity
What is streptomycin used for?
TB
Mycoplasma
Name an oxazolidinone
Linezolid
What is the MoA of oxazolidinone?
Interferes with binding of 50s rRNA
What is the MoR of oxazolidinone?
Rare
Mutations in 23S rRNA
What are oxazolidinone used for?
MRSA
VRE
What is the MoA of chloramphenicol?
Binds 50S subunit.
Prevents peptide formation
What is the MoR to chloramphenicol?
Plasmid encoded CAT gene
What is chloramphenicol used for?
Topical-eye infections
PO- meningitis, typhoid fever
What are the side effects of chloramphenicol?
Peripheral or optic neuritis Bone marrow suppression Aplastic aneamia Grey baby syndrome GIT alters flora
Name some tetracyclines
Doxycycline
Minocycline
Oxytetracycline
What is the MoA of tetracyclines?
Binds to 16S RNA 30 subunit
Prevents tRNA entering A site
What is the MoR to tetracyclines?
Increased efflux
What are tetracyclines used for?
Acne
SSTIs
Mycoplasma
Peridontal disease
What are the side effects of tetracyclines?
GI Deposition in bone/teeth Liver damage Headache Vertigo Phototoxicity
Name some macrolides
Erythromycin
Azithromycin
Clarithromycin
Name some Lincosamides
Clindamycin
Cleocin
What is the MoA of macrolides, lincosamides and streptogramins?
Binds to P site on 23S rRNA 50S subunit
Inhibits translocation and release of tRNA
What is the MoR to macrolides, lincosamides and streptogramins?
Methylation of 23S RNA
Increased efflux
Ribosomal mutation
What are macrolides used for?
RTI
STI
GI
SSTI
What are lincosamides used for?
Staph bone and joint infections
RI
Peritonitis
Septicaemia
What are the side effects of macrolides?
GI Choleostatic jaundice Reversible ototoxicity Allergic reactions Arrhythmias
Wht are the side effects of lincosamides?
Diarrhoea
What is the MoA of fusidic acid?
Binds EF-G:GDP complex to ribosome
Inhibits translocation of tRNA
What is the MoR to Fusidic acid?
Altered EF-G
What is fusidic acid used for?
Top- skin and eye infections
PO/IV-endocarditis, osteomyelitis