Respiratory infections caused by MDRSP are an important global issue facing physicians, the response to which has been the development and approval of some antimicrobials (e.g., gemifloxacin [GEM]) for the treatment of MDRSP. Monitoring local changes in the prevalence of MDRSP and in the efficacy of new agents on a continual basis is therefore important. We examined the current prevalence of MDRSP in the U.S. in adults geographically and by patient age.
TSN Database-USA (2003 only) was used to evaluate the current prevalence of MDRSP in 9 geographic regions of the U.S. (Atlanta, Baltimore/DC, Carolinas, Central Florida, Chicago, Dallas, Los Angeles, Ohio, South Florida). The prevalence of MDRSP from these regions combined was also analyzed according to patient age (18–44 y, 45–65 y, >65 y). MDR was defined as resistance (R) to ≥2 among PEN, erythromycin (ERY), and trimethoprim-sulfamethoxazole (SXT). In addition, we selected 30 MDRSP strains to evaluate the in vitro activities of respiratory fluoroquinolones (GEM, gatifloxacin [GAT], moxifloxacin [MXF], and levofloxacin [LFX]).
Overall, 19.2% of the SP collected were MDR; R to PEN, ERY, and SXT was the most common MDR phenotype. By region, MDR was lowest in Los Angeles (9.1%) and highest in South Florida (32.2%); MDR was >20% in Baltimore/DC, Central Florida, and Dallas. According to patient age, MDR was lowest among SP collected from patients 18–44 y (10.4%), compared with patients 45–65 y (19.6%) and >65 y (24.2%). R to PEN, ERY, and SXT was the most common MDR phenotype encountered in all patient age groups. For the 30 MDRSP centrally tested, the fluoroquinolone MIC ranges were as follows: 0.008–0.03 mg/L (GEM), 0.12–0.25 mg/L (GAT), 0.06–0.25 mg/L (MXF), 0.5–1 mg/L (LFX).
MDRSP in adults is an important issue faced in both the hospital and community settings and shows an increased prevalence with an increase in patient age.
GEM was the most active fluoroquinolone tested against MDRSP and should continue to be monitored as it is introduced into clinical use.
M.E. Jones, None.