Antimicrobials II Flashcards
Aminoglycosides
Gentamicin and Amikacin
Aminoglycosides use
Severe sepsis
Aminoglycosides- Side Effects (3)
Nephrotoxicity
Ototoxicity
Neuromuscular Blockade
How do Macrolides work?
Bind to 50S of bacteria
Examples of Macrolides (3)
14-ring: Erythromycin (New- Clarithromycin)
15-ring: Azithromycin
16-ring: Josamycin
Macrolides are active against what? (3)
1- Gram-positive cocci
2- Gram-negative coccobacilli
3- Atypical and Intracellular bacteria
Macrolides- Uses (2)
Respiratory infection
UTI
Macrolides- Side Effects (3)
Generally safe
Given in case of penicillin allergy
GI disturbance
Clindamycin- Mechanism of action
50S ribosome
What is clindamycin active against? (2)
Gram-positive aerobes
Anaerobes
Clindamycin- Side Effects (2)
Clostridium difficile-associated diarrhea
Pseudomembranous colitis
Tetracycline- Mechanism of Action (2)
Attach to 30S ribosome to prevent binding to tRNA
Bacteriostatic
What is Tetracycline active against? (4)
Chlamaydia
Mycoplasma
Rickettsia
Spirochetes
Tetracycline- Side Effects (5)
GI disturbance
Photosensitvity
Deposition in developing bone+teeth (brown discoloration)
Contraindicated in children and pregnancy
Hypersensitivity skin reaction
Chloramphenicol- Mechanism of Action (2)
Act on peptidyl transferase enzyme that link amino acids in growing peptide chain
Bacteriostatic agent
Chloramphenicol- Side Effect (1)
Irreversible bone marrow aplasia
Chloramiphenicol- Clinical Use (2)
Eye drops
Ointments (topical)
Fusidic Acid- Properties (5)
Does not bind directly to ribosomes Anti-staphylococcal only (Narrow) Bacteriostatic Not used alone bc resistance develops during treatment Penetrate well to bone
Colistin- Mechanism of Action (3)
Bacterial cell membrane
Act with LPS in outer membrane
Potential anti-endotoxin activity (binds and neutralizes LPS)
Colistin- Spectrum of Activity
Gram-negative aerobic bacilli
Colistin- Toxicity (2)
Neurotoxicity
Nephrotoxicity
Linezolid- Mechanism of Action (3)
Inhibits Initiation process of protein synthesis
Inhibits virulence factor expression and decrease toxin production in Gram-positive
Bacteriostatic
Linezolid- Spectrum of Activity
Gram-positive bacteria
Linezolid- Uses (1)
Against resistant bacteria e.g. MRSA, VRE
Linezolid- Side Effects (1)
Thrombocytopenia
Tigycycline- what is it used against? (2)
1- Broad (Many Gram +ve and -ve)
2- Multidrug-resistant strains of Gram +ve e.g. MRSA and MRSE, Pencillim-resistant streptococcus pneumonaie, and VRE
Tigycycline- Clinical Indications (3)
1- Complicated intra-abdominal infections
2- Complicated skin and soft tissue infections
3- Community-acquired pneumonia
Tigycycline- Side Effects (2)
Hepatic toxicity
Not recommended for pregnant women or children <8 years (Like Tetracycline)
Anti-TB drugs (Sterilizing)
Rifampicin
Pyrazinamide
Anti-TB drugs (Bactercidal)
Isoniazid
Ethambutol Streptomycin
Anti-TB drugs (Bacteriostatic)
Ethinomide
P-aminosalycilic acid
Host Factors- Quinolone
contraindication in children
Damage to cartilage
Host Factors- Penicillin and Cephalosporin
Renal function
Host Factors- Hepatic
Chloramphenicol —> Gray Baby syndrome
Sulphonamides —> Hyperbilirubinaemia —> Kernicterus
Host Factors- Ciprofloxacin
Damage growing cartilage
Host Factors- Isonazid
Hepatotoxicity
Toxicity starts after 50
Pregnancy- Safety (3)
Penicillin, Cephalosporins, Erythromycin
Pregnancy- Teratogenic (3)
Rifampcin, Metronidazole!!, Fluoroqionlones
Site of Infection- Meningitis
(Can cross blood-brain barrier)
Chloramphenicol- Excellent without inflammation
Penicillin + Cephalosporin- Excellent only with Inflammation
Aminoglycosides- Poor penetration
Site of Infection- Endocarditis
Synergy
Site of Infection- Osteomyelitis
Clindamycin
Ciprofloxacin
Fusidic acid
Prophylaxis- Medical (3)
Rheumatic heart diseases
Endocarditis
Meningococcal meningitis contacts
Prophylaxis- Surgery (2)
Before surgery
Prevent wound infection