Which type of bacterial resistance is common with fluoroquinolones?

• A. Altered forms of DNA gyrase
• B. Increased permeability of bacterial cell wall
• C. Overproduction of ribosomal proteins
• D. Metabolic inactivation of the drug

Answer: (A)

Fluoroquinolones are a class of antibiotics that work by inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes critical for DNA replication and transcription. One common mechanism of bacterial resistance to fluoroquinolones is the alteration of DNA gyrase, which reduces the binding affinity of the antibiotic to its target. This alteration can occur through mutations in the genes encoding these enzymes, leading to a selective advantage for resistant strains when exposed to fluoroquinolones.

As bacteria evolve and adapt, these mutations in DNA gyrase can significantly reduce the effectiveness of fluoroquinolones, allowing the bacteria to survive despite the presence of the drug. This mechanism is widely recognized as a key factor in the development of resistance to fluoroquinolones in various bacterial species.

The other potential mechanisms of resistance, while relevant in other contexts, do not specifically pertain to fluoroquinolones in the same way. For example, increased permeability of the bacterial cell wall is more commonly associated with resistance to other classes of antibiotics, while overproduction of ribosomal proteins is relevant for some classes of antibiotics targeting protein synthesis rather than fluoroquinolones. Lastly, metabolic inactivation involves the drug being chemically altered in a way that