242. Macrolide Resistance in Streptococcus pneumoniae in the United States and Canada – TEST 2008-2010
Session: Poster Abstract Session: Antimicrobial Susceptibility and Resistance
Friday, October 21, 2011
Room: Poster Hall B1

Background: Macrolide resistance rates against S. pneumoniae have risen steadily for the past decade in North America.  The Tigecycline Evaluation Surveillance Trial (TEST) program is an ongoing global surveillance designed to follow trends in antimicrobial activity.  As part of the TEST program this report evaluates the current macrolide resistance rates in the United States and Canada and the in vitro activity of tigecycline against these isolates from 2008 to 2010. Methods: 940 clinical isolates were collected from 149 investigative sites in the United States (n=808) and Canada (n=132). Clinical isolates were identified to the species level at each participating site and confirmed by the central laboratory. Minimum Inhibitory Concentrations (MICs) were determined by the local laboratory using supplied broth microdilution panels and interpreted according to CLSI and FDA guidelines. Results: Tigecycline MIC50, MIC90, and % susceptible were 0.015, 0.03 mcg/ml and 96%, respectively, against both macrolide-susceptible and macrolide-resistant S. pneumoniae in this study  Regional macrolide-resistant rates for the US (with CDC regions) and Canada are as follows:  

Conclusion: Overall, the macrolide resistance rate was 35% for S. pneumoniae from the United States (37%) and Canada (21%). Macrolide resistance varied from a low of 16% in the Mountain states to a high of 58% in the East South Central states of Alabama, Kentucky, Mississippi, and Tennessee. Tigecycline was highly active in vitro against this North American collection of S. pneumoniae without regard to macrolide resistance with over 96% of all isolates susceptible.   





Subject Category: A. Antimicrobial agents and Resistance

Samuel Bouchillon, MD1, Meredith Hackel, PhD1, Stephen Hawser, PhD2, Brian Johnson, BS1, Daryl Hoban, PhD1 and Michael Dowzicky, MS3, (1)IHMA, Inc., Schaumburg, IL, (2)IHMA Europe Sārl, Epalinges, Switzerland, (3)Pfizer, Inc., Collegeville, PA


S. Bouchillon, Pfizer, Inc.: Consultant, Consulting fee

M. Hackel, Pfizer, Inc.: Consultant, Consulting fee

S. Hawser, Pfizer, Inc.: Consultant, Consulting fee

B. Johnson, Pfizer, Inc.: Consultant, Consulting fee

D. Hoban, Pfizer, Inc.: Consultant, Consulting fee

M. Dowzicky, Pfizer, Inc.: Employee, Salary

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.