Page 117 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

4- Nucleic acid synthesis inhibitors

Quinolones

Synthetic drugs
Mechanism: work by inhibiting two topoisomerases
• DNA gyrase (topoisomerase II) in Gram negative

• Topoisomerase IV in Gram positive

leading to inhibition of DNA synthesis and eventually bacterial death

➢ have broad activity against various bacteria

➢ Mostly fluorinated = Fluoroquinolones (except nalidixic acid)

Generation/ Spectrum activity Uses
Drugs

- Gram-negative organisms • Oldest quinolone
st
1 except Pseudomonas • Only used for urinary tract
Nalidixic acid
species infections

- Gram negative (including • urinary tract infections
nd
2
Pseudomonas species) • sexually transmitted diseases
Ciprofloxacin - some Gram+ (S. aureus) • skin and soft-tissue infections

Ofloxacin - some atypical bacteria

Norfloxacin

nd • Respiratory infections
rd
3 - Same as 2 generation
with extended Gram+
Levofloxacin
and atypical coverage

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