245. In Vitro Activity of Tigecycline against Commonly Isolated Pathogens of Skin and Skin Structure Infections in Latin America  – TEST 2007-2010
Session: Poster Abstract Session: Antimicrobial Susceptibility and Resistance
Friday, October 21, 2011
Room: Poster Hall B1

Background: Skin and skin structure infections (SSTIs) are frequently encountered in clinical practice and are among the most common indications for antibiotic therapy and hospital admission. The Tigecycline Evaluation and Surveillance Trial (TEST) has been monitoring susceptibility to tigecycline globally since 2004. This study reports on the activity of tigecycline against clinical isolates from SSTIs in Latin America. Methods:  A total of 1,736 clinical isolates of key species from SSTI were collected and identified at 53 sites in 9 countries in Latin America in 2007-2010. MICs were determined by broth microdilution using CLSI guidelines.  Susceptibility to tigecycline was interpreted using FDA breakpoints. Results: Resistant phenotypes were found frequently in SSTI pathogens with rates in Latin America ranging from 20% for vancomycin-resistant (VR) E. faecium (out of all E. faecium), 30% for ESBL+ E. coli, 45% for ESBL+ K. pneumoniae, and 46% for MRSA. Tigecycline's in vitro activity is summarized below:

Organism

n

MIC50

MIC90

%S

Acinetobacter baumannii

119

0.5

2

na

Enterobacter cloacae

245

0.5

2

97.6

Enterococcus faecalis

148

0.12

0.25

100

Enterococcus faecium

44

0.12

0.25

97.7

    E. faecium, VR

9

--

--

8/9

Escherichia coli

223

0.25

0.5

100

    E. coli, ESBL+

66

0.25

0.5

100

Klebsiella pneumoniae

182

0.5

2

95.6

    K. pneumoniae, ESBL+

81

0.5

2

95.1

Pseudomonas aeruginosa

256

8

16

na

Serratia marcescens

103

1

2

98.1

Staphylococcus aureus

348

0.12

0.25

100

    S. aureus, MRSA

160

0.12

0.25

100

    S. aureus, MSSA

188

0.12

0.25

100

Streptococcus agalactiae

68

0.03

0.06

100

na - breakpoint not defined; ESBL+ - extended-spectrum β-lactamase positive; MRSA – Methicillin-resistant S. aureus. For n<10, MICs and % S not reported, n susceptible / n total is shown.

Conclusion: Tigecycline demonstrated potent in vitro activity against gram-negative and gram-positive SSTI pathogens including resistant phenotypes.  This is particularly important in Latin America, where rates of resistant phenotypes were high, especially ESBL+ isolates. MIC90 values ranged from 0.25 to 2 mcg/ml for all studied species, except P. aeruginosa against which tigecycline is known to have very little activity. Susceptibilities were >95% for all studied species for which breakpoints exist.

 


Subject Category: A. Antimicrobial agents and Resistance

Sibylle Lob, MD, MPH1, Daryl Hoban, PhD1, Samuel Bouchillon, MD1, Robert Badal, BS1, Stephen Hawser, PhD2 and Michael Dowzicky, MS3, (1)IHMA, Inc., Schaumburg, IL, (2)IHMA Europe Sārl, Epalinges, Switzerland, (3)Pfizer, Inc., Collegeville, PA

Disclosures:

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

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

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

R. Badal, 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.