Quinolones are active against the following bacteria:
Haemophilus influenzae
Moraxella catarrhalis
Mycoplasma species
Chlamydia spp.
Chlamydia spp.
Legionella spp.
Enterobacteriales (formerly Enterobacteriaceae)
Pseudomonas aeruginosa (particularly ciprofloxacin)
Mycobacterium tuberculosis
Some atypical mycobacteria
Some methicillin-susceptible Staphylococci
Methicillin-resistant Staphylococci (MRSA) in hospitals are often resistant. Older fluoroquinolones have poor activity against streptococci and anaerobes. Newer fluoroquinolones have reliable activity against streptococci (including S. pneumoniae with reduced penicillin sensitivity) and some anaerobes; in particular, moxifloxacin has activity against most clinically significant obligate anaerobes.
Delafloxacin is the newest fluoroquinolone and is active against
Gram-negative bacteria, including P. aeruginosa
Gram-positive bacteria, including MRSA, and atypical respiratory pathogens
Anaerobes
As fluoroquinolone use increases, resistance (especially to older fluoroquinolones) is increasing in bacteria such as Enterobacteriaceae, P. aeruginosa, S. pneumoniae, and Neisseria. Despite this, fluoroquinolones still have many clinical uses (see table Some Clinical Uses of Fluoroquinolones).
Due to increasing resistance worldwide, fluoroquinolones are no longer recommended for the empirical treatment of gonorrhea. However, single-dose ciprofloxacin is very effective for the treatment of gonococcal infections caused by strains of Neisseria gonorrhoeae that are sensitive to this antibiotic.
