ANTIBIOTIC SUMMARY Flashcards by Emily Holding

What classes of Abx act on cell wall synthesis?

B-lactams
Glycopeptides
Bacitracin
Cycloserine
Fosfomycin

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What classes of Abx act on the cell membrane?

Polymyxins

Lipopeptides

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What classes of Abx act on nucleic acids?

Sulphonamides
Quinolones
Rifamycins
Nitromidazoles
Nitrofurantoin

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What classes of Abx act on protein synthesis?

Aminoglycosides
Oxazolidinone
Chloramphenicol
Tetracyclines
MAcrolides
Lincosamides
Streptogramins
Fusidic acid

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Name some B-lactams

Pen G
Pen V
Cephalosporins
Carbapenems
Monobactams

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What is the MoA of B-lactams?

Binds PBP preventing Xlinking of PG chain.
Incorporated into chain.
Stimulates autolysins

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What is the MoR of B-lactams?

B-lactamases
Altered PBP
Mutations in porins

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What are B-lactams used for?

Throat infections
Endocarditis
Meningitis
Pneumonia
Cellulitis
Osteomyelitis

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What are the side effects of B-lactams?

Hypersensitivity
Neurotoxicity
Renal failure
Diarrhoea
Pseudomonas colitis

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Name some glycopeptides

Vancomycin

Teicoplanin

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What is the MoA for glycopeptides?

Binds d-ala-d-ala.
Inhibits transglycosidase enzymes-PG nit incorporated
Inhibits X-linking

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What is the MoR to glycopeptides?

D-ala-d-ala chages fo d-ala-dlactae/serine

Destabilises binding of vanc

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What are glycopeptides used for?

C.diff infections

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What are the side effects of glycopeptides?

Pain &amp; thrombophlebitis
Renal toxicity
Ototoxicity
Blood disorders
Anaphylactoid reactions

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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

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What is MOR to bacitracin?

Increased phosphorylated lipid carrier

Efflux pumps

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What is bacitracin used for?

Topically in combo with other abxs to prevent skin, eye and wound infections

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What are the side effects of bacitracin?

Contact allergic dermatitis

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What is the MoA of cycloserine?

Prevents formation of D-ala-d-ala through activation of 2 enzymes converting L-ala to D-ala

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What is the MoR to cycloserine?

Overexpression of 1 converting enzymes

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What is cycloserine used for?

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What are the side effects of cycloserine?

CNS
Rashes
Liver damage

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What is the MoA of fosfomycin?

Inhibits enzyme NAG-enolpyruvate transferase

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What is the MoR to Fosfomycin?

Plasmid and chromosomally encoded enzymes break open the epoxide ring of fosfomycin

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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

ANTIBIOTIC SUMMARY Flashcards

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