- Are bactericidal antibiotics.
- Bacterial cell wall synthesis completely depends on transpeptidase enzyme.
- Penicillin inhibits bacterial cell wall synthesis by blocking transpeptidase after binding to penicillin-binding protein (PBP).
- NATURAL(Endrin plant Penicillin)
ROUTE OF ADMINISTRATION:
- Piperacillin(anti-pseudomonal drug)
- (Methicillin is Acid Labile penicillin)
SPECTRUM OF ACTIVITY:
RESISTANCE TO ENZYME:
RESISTANCE TO β-LACTAMASE
NON- RESISTANCE TO β-LACTAMASE
RESISTANCE TO ACIDS:
- Otitis Media,
- Scarlet Fever
- Rheumatic Fever (1.2 MU every 4 weeks of benzathine penicillin)
- Subacute Bacterial Endocarditis
- Treatment of spreading streptococcal cellulitis
- Lobar Pneumonia.
- Antipseudomonal penicillins includes carboxypenicillin & ureidopenicillins.
- Ophthalmia Neonatorum
- Syphilis(2.4 MU single i.m. of benzylpenicillin )Treatment for clostridial myonecrosis
- Presence of fever, jaundice and renal failure in a sewage worker (contact with rat urine) suggests a diagnosis of Wen syndrome or Icterohemorrhageic fever caused by leptospirae.
- Penicillin G (intravenously) is recommended agent.
- Treatment of contaminated wound in Gas Gangrene
- Drug of choice for Treponema Pallidum
- Actinomycosis: For thoracic actinomycosis
- Enterococcus faecalis: When isolated in blood, requires synergistic activity of penicillin plus an aminoglycoside for appropriate therapy.
- Rat bite fever
- Rheumatic Fever
- Bacterial Endocarditis
- rash, itching, urticaria, fever
- wheezing, angioneurotic edema, serum sickness, exfoliative dermatitis (less common)
- Anaphylaxis (rare, but fatal)
- Bowel, respiratory and cutaneous microflora can undergo changes
- Jarisch- Herxheimer Reaction
- Pain at injection site
- Mental confusion, muscular twitching, convulsions, coma
- Due to interference of platelet function
- Intrathecal PnG injections (not recommended)
- Arachnoiditis, degenerative changes in spinal cord
- Accidental IV procaine penicillin injection
- CNS stimulation, hallucinations, convulsions.
Beta-lactamase (Penicillinase) Production
- Most common mechanism
- Both gram-positive & gram-negative organism produces beta-lactamase which opens beta-lactam ring inactivating antibiotic.
Altered penicillin-binding protein (PBP)
- Bacteria alters penicillin-binding protein structure, transpeptidase.
- Hence, prevents penicillin-binding site.
- Eg: In case of MRSA.
- Treatment of S. aureus infection with penicillin is often complicated by the production of penicillinase by S. aureus
- Carbenicillin is NON- RESISTANCE TO β-LACTAMASE
- Syphilis, Anthrax and Bacterial meningitis are therapeutic uses of penicillin G
- Antipseudomonal penicillins include the carboxypenicillin and the ureidopenicillins.
- Penicillin Binding Proteins (PBPs) are essential for cell wall synthesis
- Penicillin Binding Proteins (PBPs) act as carboxypeptidases and transpeptidases
- Alteration in PBP’s is the primary bases of resistance in MRSA
- β- Lactamase production is the most common mechanism of resistance to Penicillin
- Alteration in permeability/penetration of antibiotic causes resistance only in Gram-negative bacteria
- β-Lactamase production causes resistance in both Gram-positive and Gram-negative bacteria
- Penicillin would be LEAST effective in treating Mycoplasma pneumonia
- Enterococcus faecalis when isolated in the blood, requires the synergistic activity of penicillin plus an aminoglycoside for appropriate therapy
- Plant penicillin is Endrin
- Penicillins inhibits cell wall synthesis
- Methicillin is Acid Labile penicillin
- Penicillinase-resistant penicillin Methicillin
- The dosage of benzylpenicillin in the treatment of primary syphilis is 2.4 MU single i.m.
- Treatment for clostridial myonecrosis is Penicillins
- Penicillin is Drug of choice for Treponema Pallidum
- Penicillin is Drug of choice for thoracic actinomycosis
- Penicillin in high doses can cause convulsions
- The clinical presentation of fever, altered sensorium and purpuric rashes, is highly suggestive of meningococcal meningitis is treated with Penicillin
- TOC for penicillin-resistant gonorrhoea Ceftriaxone
- Presence of fever, jaundice and renal failure in a sewage worker (contact with rat urine) suggests a diagnosis of Wen syndrome or Icterohemorrhageic fever caused by leptospirae. Penicillin G (intravenously) is the recommended agent.
- Treatment of spreading streptococcal cellulitis is Penicillin
- Treatment of contaminated wound in Gas Gangrene is Penicillin
- Rapidly spreading infection of the external auditory canal with the involvement of the bone and presence of granulation tissue point towards malignant otitis externa treated with Penicillin
- Penicillin is used in the treatment of quinsy
- Piperacillin is an anti-pseudomonal drug of penicillin-class
- Dose and duration of benzathine penicillin for prophylaxis of rheumatic fever is 1.2 MU every 4 weeks