Susceptibility of Staphylococcus aureus among skin and wound specimen sources in the United States: laboratory-based surveillance study 2005–2007

Abstract number: P590

Tillotson G., Draghi D., Sahm D., del Fabro T., Tomfohrde K., Critchley I.

Objectives: As meticillin-resistant Staphylococcus aureus (SA) infections increase, current data are needed to assess the susceptibility (S) of SA in the US. In this study rates of antimicrobial S for SA were reported from US laboratories from 2005 to 2007 with regional trends of resistance (R) identified.

Methods: The Surveillance Network (TSN®) comprises 296 laboratories from the 9 census regions of the US. TSN laboratories reported S data for antimicrobials by isolate with specimen source description, region, year of isolation, and patient location (PL including outpatient [OP]; inpatient [IN]; intensive-care unit [ICU]). Commonly prescribed agents were studied, these included ciprofloxacin (CIP), levofloxacin (LEV), clindamycin (CLI), daptomycin (DAP), erythromycin (ERY), gentamicin (GEN), oxacillin (OX), linezolid (LIN), and trimethoprim-sulfamethoxazole (SXT). S data from skin and wound specimen sources were studied during 2005 to 2007. Specific phenotypes were further investigated for associated R and multidrug R (MDR) patterns. Data was interpreted using current CLSI standard criteria.

Results: There were >380,000 isolates of SA tested and reported for the period 2005 to 2007. OX R was observed for 57.0% of SA in 2007 with little change from 2005. There was little difference in rates of OX R between OP and IN cohorts. Among all PL in 2007, R rates (%) were 18.6 for CLI; 64.8 ERY; 37 CIP; 39.5 LEV. Generally as expected, isolates from the ICU tended to be slightly more resistant among the agents studied. Regional variation in R rates was noted with the highest rates in the central regions and lowest in New England and Mid Atlantic regions among the agents studied. There was high activity observed for SXT and GEN. LIN R was extremely rare and DAP R was not observed. MDR rates (%) varied among patient location: 28.5 OP; 39.3 IN; and 51.5 ICU.

Conclusions: SA has become OX-resistant in both the community and hospital setting; however, little change was observed in the past 3 years. MDR strains are now common in all settings and empiric therapy should be guided by local susceptibility patterns due to the regional variation. Currently, SXT, GEN, DAP, and LIN exhibited S rates >95%; however, continued monitoring is warranted due to the propensity of this organism to become resistant.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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