Which types of bacteria are primarily targeted by fluoroquinolones?

Fluoroquinolones are a class of antibiotics that are particularly effective against a broad spectrum of bacteria, with a strong emphasis on Gram-negative bacteria. They work by inhibiting bacterial DNA gyrase and topoisomerase IV, which are critical enzymes involved in DNA replication and repair. This mechanism makes fluoroquinolones particularly potent against Gram-negative organisms such as Escherichia coli and Pseudomonas aeruginosa, which are commonly implicated in various infections.

In addition to their effectiveness against Gram-negative bacteria, fluoroquinolones also display activity against some atypical bacteria, such as those causing respiratory infections, including certain strains of Mycoplasma and Chlamydia. However, they are generally less effective against Gram-positive bacteria compared to other antibiotic classes.

Thus, the correct identification of fluoroquinolones' primary targets reflects their significant activity against both Gram-negative and atypical bacteria, while their impact on Gram-positive bacteria is notably less pronounced. This specificity is a crucial point in understanding the appropriate use of fluoroquinolones in clinical settings.