258. Surveillance Trends in the in Vitro Activity of Tigecycline, TEST 2004 to 2010: A Global Perspective
Session: Poster Abstract Session: Antimicrobial Susceptibility and Resistance
Friday, October 21, 2011
Room: Poster Hall B1

Background: Tigecycline, the first member of the glycylcyclines, was marketed in 2005 and has demonstrated activity against multi-resistant species and phenotypes. Due to its chemical structure, resistance to tigecycline is reportedly difficult to produce even in the laboratory. The TEST program is an ongoing surveillance program monitoring the in vitro activity of tigecycline and comparator agents globally. Methods: 139,476 clinical isolates were collected from about 540 investigative sites in 60 countries. MICs were determined by broth microdilution and interpreted according to CLSI/FDA guidelines. áResults: % susceptible (%S) and MIC90 (mcg/ml) for tigecycline and key species are as follows:

2004

2005

2006

2007

2008

2009

2010

Organism (n per year)

%S

MIC90

%S

MIC90

%S

MIC90

%S

MIC90

%S

MIC90

%S

MIC90

%S

MIC90

Acinetobacter spp.

1494/1438/2015/2678/2607/2873/917

NA

1

NA

1

NA

1

NA

2

NA

2

NA

2

NA

2

Enterobacteriaceae

8562/9243/12833/16662/15569/17089/5286

96.5

1

96.7

1

96.9

1

97.7

1

97.1

2

96.8

2

96.7

2

áá ESBL producers

áá 468/575/1066/1224/1775/1992/452

93.0

2

95.7

2

95.6

2

96.5

2

96.2

2

96.6

2

95.4*

2

Enterococcus spp.

1530/1729/2348/3034/2710/3062/990

99.9

0.12

99.9

0.12

99.8

0.12

99.8

0.25

99.5

0.25

99.5

0.25

100**

0.25

á áVRE

ááá 217/280/327/331/245/289/88

100

0.12

99.6

0.12

100

0.12

99.7

0.12

98.0

0.25

97.9

0.25

100**

0.25

S. aureus MSSA

1421/1578/2099/2933/2935/3115/895

100

0.12

100

0.12

100

0.25

100

0.25

100

0.25

100

0.25

100

0.25

S. aureus MRSA

1161/1412/1537/2098/1662/1698/263

100

0.25

100

0.25

99.9

0.25

100

0.25

100

0.5

99.8

0.5

100

0.5

NA=no breakpoint defined; *significant increase in %S (p<0.05, Cochran-Armitage test for trend); **significant decrease in %S

Conclusion: Tigecycline's MIC90 values only changed by one doubling dilution over 6 years from its pre-marketing (2005) values. There was a very slight but statistically significant decreasing linear trend áin % susceptible for Enterococcus spp. and VRE, while ESBL producers showed a slight increase in susceptibility over time (p<0.05). Tigecycline activity was retained even against strains resistant to other agents, including ESBL-producers, multi-resistant Acinetobacter spp., MRSA and VRE. For all reported organisms with existing breakpoints susceptibility was >95% in 2010.


Subject Category: A. Antimicrobial agents and Resistance

Daryl Hoban, PhD1, Samuel Bouchillon, MD1, Meredith Hackel, PhD1, Jack Johnson, MS, MBA1, Stephen Hawser, PhD2 and Michael Dowzicky, MS3, (1)IHMA, Inc., Schaumburg, IL, (2)IHMA Europe SÓrl, Epalinges, Switzerland, (3)Pfizer, Inc., Collegeville, PA

Disclosures:

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

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

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

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

S. Hawser, 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.