244. Tigecycline in Vitro Activity against Extended Spectrum Beta-Lactamase Producers in Latin America  – TEST 2008-2010
Session: Poster Abstract Session: Antimicrobial Susceptibility and Resistance
Friday, October 21, 2011
Room: Poster Hall B1

Background: The emergence and dissemination of extended spectrum beta-lactamase (ESBL) producing isolates represents an alarming trend in increasing resistance to antimicrobial agents in many countries in recent years.   This study looks at ESBL rates from 2008 through 2010 in Latin America and the effect on susceptibilities to common therapeutic agents.  This study is part of the larger Tigecycline Evaluation and Surveillance Trial (TEST), an ongoing global surveillance designed to follow trends in antimicrobial activity of tigecycline and comparators.  Methods: 3,765 clinical isolates from all sources were collected from 113 cumulative investigator sites in Latin America. Evaluations were conducted on ESBL producing strains of E. coli, K. oxytoca, and K. pneumoniae. 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 current CLSI and FDA (tigecycline) guidelines. Results: A total of 1,077 (29%) ESBLs were confirmed: 498/1964 (25%) E. coli; 23/153 (15%) K. oxytoca; 556/1648 (34%) K. pneumoniae.  Tigecycline in vitro activity against all ESBLs demonstrated MIC50, MIC90, and %Sus of 0.5 mcg/ml, 2 mcg/ml, and 96%, respectively.  % Susceptible of tigecycline and comparators against all ESBLs are presented in the following figure:

Conclusion: The overall ESBL production rate (29%) in E. coli and Klebsiella from Latin America is at the highest level recorded for this region in a decade. Tigecycline in vitro activity (96% susceptible) against ESBL producers is comparable to meropenem (90.9% Sus) and greater than that seen for either amikacin or piperacillin-tazobactam (both <80%). 





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.