Table 1.

Classification of Quinolones

Generation	Drugs	Spectrum of Activity		Anaerobes/Atypicals
		Gram Positive	Gram Negative
First	Nalidixic acida Cinoxacin	Minimal Gram-positive	Enterobacteriaceae	None
Second	Ciprofloxacinb,c Levofloxacinb,d Enoxacin Fleroxacin Ofloxacin Lomefloxacin Norfloxacin Pefloxacin	Methicillin-susceptible Staphylcoccus aureus, Streptococcus pneumoniae, Other streptococci	Enterobacteriaceae Pseudomonas aeruginosa Haemophilus spp., Neisseria spp., Moraxella catarrhalis	Legionella pneumophila, Chlamydia spp., Mycoplasma spp., Ureaplasma urealyticum, Mycobacterium spp
Thirde	Gatifloxacin Grepafloxacin Sparfloxacin Temafloxacin	Methicillin-susceptible S. aureus, S. pneumoniae, Listeria monocytogenes, Other streptococci	Enterobacteriaceae Haemophilus spp., Neisseria spp., Moraxella catarrhalis	Legionella pneumophila Chlamydia spp., Mycoplasma spp., Ureaplasma urealyticum Mycobacterium spp
Fourth	Moxifloxacinb,f Trovafloxacin Gemifloxacin	Methicillin-susceptible S. aureus, S. pneumoniae, Other streptococci	Enterobacteriaceae Haemophilus spp., Neisseria spp., Moraxella catarrhalis	Legionella pneumophila, Chlamydia spp., Mycoplasma spp., Ureaplasma urealyticum, Mycobacterium spp. Anaerobes

^aOnly indicated for urinary tract infections due to low systemic exposure.

^bMost commonly prescribed.

^cGreatest activity against Pseudomonas aeruginosa.

^dGreatest activity against Streptococcus pneumoniae.

^eNot available in the United States or removed from the market.

^fAdditional activity against anaerobes.