According to the Centers for Disease Control and Prevention (CDC) in the United States, the problem of Streptococcus pneumoniae resistance to fluoroquinolones has become urgent.

CDC experts studied the evolution of resistance to fluoroquinolones from 1995 to 1999. in 7 states. From 1995 to 1997 The sensitivity of 8763 strains of pneumococci isolated from patients with invasive ofloxacin infections was determined. From 1998 to 1999 The susceptibility of 6,529 strains of pneumococci to levofloxacin was determined.

The resistance level of pneumococcus to ofloxacin increased from 3.1% in 1995 to 4.5% in 1997, and more resistant strains were found in adults than in children. Researchers attribute this to the fact that fluoroquinolones are not approved for use in children. All strains of levofloxacin-resistant pneumococcus have been isolated from adult patients, but the level of resistance has increased slightly (from 0.2% in 1998 to 0.3% in 1999).

In addition, resistance of microorganisms to fluoroquinolones was combined with resistance to other antibiotics: for example, most strains resistant to levofloxacin were moderately resistant to penicillin, cefotaxime, erythromycin and / or cotrimoxazole.

According to the CDC, fluoroquinolones are more and more prescribed in the United States: from 1993 to 1998. In the United States, the administration of fluoroquinolone increased from 3.1 to 4.6 per 100 people per year. This may contribute to the emergence of fluoroquinolone-resistant pneumococci, although the level of resistance of microorganisms to fluoroquinolones is still low.