Streptococcus pneumoniae resistance to fluoroquinolones is an emerging problem in the US, according to the Centers for Disease Control and Prevention.
The CDC’s Active Bacterial Core Surveillance data from 1995-1999 from seven states revealed pneumococcal resistance to fluoroquinolones. Pneumococcal bacteria samples that were not susceptible to ofloxacin increased from 2.6 per cent in 1995 to 3.8 per cent in 1997. In both 1998 and 1999, 0.2 per cent of bacterial samples did not respond to the newer levofloxacin.
Samples not responding to ofloxacin were more common in those aged over 18 and, among these, increased from 3.1 per cent in 1995 to 4.5 per cent in 1997. Fluoroquinolone use is not licensed for those under 18. All of the samples not responding to levofloxacin were found in adults, with a prevalence that was only slightly increased, from 0.2 per cent in 1998 to 0.3 per cent in 1999.
Although pneumococci not susceptible to fluoroquinolones are now present in the US, it is unclear whether there is increased resistance. However, as stated in the editorial note, ‘trends in ofloxacin susceptibility may predict what will occur for other fluoroquinolone agents’.
Of the 15 samples not responding to levofloxacin, many also had decreased susceptibility to penicillin, trimethoprim-sulphamethoxazole, cefotaxime and/or erythromycin.
Fluoroquinolones are being increasingly prescribed and this may be contributing to the emergence of resistant pneumococci. Physicians are now urged to use these antibiotics – including ciprofloxacin and newer, more powerful ones such as grepafloxacin, gatifloxacin and moxifloxacin – more appropriately and judiciously (MMWR, 2001; 50: 800-4).