Antibiotics for chapter 10

Cillin family

Beta-lactams, inhibit cell wall synthesis by binding to enzymes that cross link NAM subunits, affect the log phase

Penicillin

Interferes with the creation of peptidoglycan, especially useful against Gram+

Methicillin

Inhibit cross linkage between NAM NAG subunits, works on gram +

Ampicillin (SAM-20)

a β-lactam antimicrobial, with sulbactam as a β-lactamase inhibitor. The combination of ampicillin and sulbactam demonstrates synergy in addressing bacterial strains resistant to ampicillin (used in resistant infections)

Augmentin

penicillin antibiotic that combines amoxicillin with clavulanate (chemical not antibiotic), a beta-lactamase inhibitor, to treat bacterial infections

Vancomycin

Interfere with particular bridges that link NAM subunits in many Gram-

positive bacteria

– widely used drug in US hospitals, for CDI, MRSA, pen allergies (not a beta

lactam)

– Renal failure issues, dosage monitoring required.

Bacitracin

Blocks transport of NAG and NAM from cytoplasm (Bacteriostatic)

Cephalosporin

beta lactam, similar MOA to penicillin (useful alternative for patients with mild penicillin allergy)

Isoniazid and Ethambutol

Disrupt mycolic acid formation in Mycobacterial species (only effects gram +, so it is narrow spectrum)

Macrolides

Block movement of mRNA through ribosome which stops translation because can’t read next codon, halts protein synthesis completely

Streptomycin

Alters shape of 30S (small subunit) slightly so codons aren’t read correctly (translation is still going, but incorrect proteins produced)

Cloramphenicol

Binds to 50S (big subunit) during translation, inhibits formation of peptide bonds between amino acids (protein synthesis halted)

Tetracyclines

Interfere with attachment of TRNA to arrival site during translation by blocking the site (halts protein synthesis)

Nystatin And amphotericin B (drugs not antibiotic)

attach to ergosterol (important for fluidity of membrane) in fungal membranes, disrupts cytoplasmic membrane (bacteriocidal)

Azoles

Inhibit ergosterol synthesis

Polymyxin (narrow spectrum)

Incorporated into cell membrane, targets G- because of outer membrane

• disadvantage: toxic to human kidneys (organ fxn monitored)

• Skin infections, eye infections, UTI, meningitis

Trimethoprim and Sulfonamides

Contain mimics of PABA, which is needed in bacterial metabolic pathway, binds to enzymes, interferes with folic acid synthesis

Amantadine & rimantadine, arildone, Pleconaril

Amantadine & rim: Prevent viral uncoating, target viral metabolism

Arildone: prevent viral uncoating

Pleconaril: prevent viral attachment

Protease and reverse transcriptase inhibitors

Halts HIV replication cycle by interfering with enzymes

Ciprofloxacin

Act against prokaryotic DNA gyrase, blocks DNA replication

Actinomycin, Metronidazole

Inhibits transcription – binds initiation complex, toxic to human cells