Penicillins (β-Lactams Antibiotics)
Also known as Aminopenicillins
They are often combined with β-Lactamase Inhibitors to be effective against β-Lactamase producing Resistant Bacteria
Drugs:
- Ampicillin (often combined with with Sulbactam)
- Ampicillin Sodium
- Ampicillin Trihydrate
- Amoxicillin (often combined with with Clavulanic Acid)
- Amoxicillin Sodium: Most water soluble, can be injected IV
- Amoxicillin Trihydrate: Less water soluble, can’t be given IV (Given PO, SC, IM instead)
Antibacterial spectrum: (When combined with β-Lactamase Inhibitors): Similar to 2nd Generation Cephalosporins
- Almost identical between Ampicillin and Amoxicillin
- All bacteria covered by Narrow Spectrum Penicillins and more
- Almost all Gr+ bacteria:
- Including: *Enterococcus, Staphylococcus
- Except Acid-fast bacteria (Mycobacterium)
- Several Gr- bacteria: Such as
- Fastidious bacteria: Pasteurella, Haemophillus, Actinobacillus, Mannheimia, Biebersteinia, Histophillus
- Associated with Respiratory tract infections
- Enterobacteriacea: E. coli, Salmonella, Klebsiella
- Associated with UTI
- Proteus
- Anaerobes: Bacteroides, Fusobacterium, Prevotella
- Associated with Oral infections and Bite wound infections
- Leptospira, Borrelia
- Associated with Vector borne infections (such as Lyme disease)
- Fastidious bacteria: Pasteurella, Haemophillus, Actinobacillus, Mannheimia, Biebersteinia, Histophillus
- Almost all Gr+ bacteria:
- Without β-Lactamase Inhibitors the spectrum is similar to Narrow Spectrum Penicillins
Pharmacokinetics:
They are water soluble > excreted in the kidney without requiring to be metabolized > High active form concentrations in the urine (higher than plasma concentration) > Good against E. coli UTI
Indication:
- All bacterial infections that Narrow Spectrum Penicillins also cover
- It is advised to favorize Narrow Spectrum Penicillins over Extended Spectrum Penicillins when possible (to reduce the impact on the bacteria we don’t need to target) but it is rarely done because Amoxicillin-Clavulanic Acid is much cheaper
- Gastrointestinal infections (E. coli, Salmonella): Currently the resistance situation is bad, so it is not really advised
- UTI (E. coli): The urine concentrations are high enough to overcome the produced β-Lactamase
- The situation is different than Gastrointestinal infections because the local (urinary tract) concentrations are higher
- Dermatitis, Soft tissue Infections, Osteomyelitis: Staphylococcus, Streptococcus
- Lyme disease: Borrelia
- Oral cavity infections, Bite wounds: Anaerobe Gr- bacteria (Bacteroides, Fusobacterium)
- Septicaemia, bacteraemia
Adverse effects:
Dysbacteriosis:
- Amoxicillin-Clavulanic Acid can’t be used in herbivorous rodents (It can be used in horses)