Antimicrobial resistance trends among sinus isolates of Streptococcus pneumoniae in the United States (2001-2005).

OBJECTIVE

To test the susceptibility of Streptococcus pneumoniae sinus isolates collected across the United States against commonly used antimicrobial agents.

STUDY DESIGN AND

SETTING

S. pneumoniae sinus isolates (N = 847) collected as part of the Tracking Resistance in the US Today Surveillance Program from 2001 to 2005 were tested against 8 antimicrobial agents.

RESULTS

In ascending order, the relative activities (% susceptible) were penicillin (51.8%), trimethoprim/sulfamethoxazole (TMP/SMX) (57.6%), erythromycin (59.5%), cefuroxime (62.0%), amoxicillin/clavulanate (85.5%), clindamycin (86.1%), levofloxacin (99.4%), and linezolid (100%; for 2004 and 2005 respiratory seasons, only). Resistance rates over the 5 years remained generally stable, although resistance to amoxicillin/clavulanate nearly doubled (from 6.5% to 12.9%). Forty percent of isolates were resistant to >or=2 agents tested.

CONCLUSIONS AND SIGNIFICANCE: Susceptibility trends among sinus S. pneumoniae isolates appear to have stabilized over the past 5 years. Resistance rates remain elevated for penicillin and macrolides, whereas the high prevalence of multidrug resistance remains a concern.