Background: Enterobacteriaceae and non-enteric
gram-negative pathogens cause serious infections among hospitalized patients,
including intra-abdominal infections (IAI). Tigecycline Evaluation Surveillance Trial
(TEST) program data were used to evaluate the in vitro activity of several
key drugs against pathogens causing IAI among patients from North America.
Methods: 378 cumulative sites from North America between 2011 and 2015
contributed
Enterobacteriaceae, P. aeruginosa,
and A. baumannii isolates
collected from IAI sources during 2011-2015. Species identification
and testing by broth microdilution was performed locally according to CLSI
guidelines. Categorical
interpretation of results was done using CLSI or FDA breakpoint (i.e.
tigecycline) criteria where appropriate. Results: The activities of
the various drugs according to organism groups are provided in the table below.
Enterobacteriaceae (1021)
ESBL +* (63)
P. aeruginosa (103)
A. baumannii (16)
Drug
%S
MIC50
MIC90
%S
MIC50
MIC90
%S
MIC50
MIC90
%S
MIC50
MIC90
Tigecycline
97.0
0.25
1
95.2
0.25
1
na**
8
> 8
na
0.12
2
Amikacin
99.6
2
4
100
4
8
98.1
4
8
81.3
2
> 64
Cefepime
90.9
≤ 0.5
2
19.1
>32
> 32
79.6
4
16
68.8
1
> 32
Levofloxacin
83.2
0.06
> 8
19.1
> 8
> 8
65.1
1
> 8
62.5
0.12
> 8
Meropenem
98.1
≤ 0.06
0.12
92.1
≤ 0.06
1
75.7
1
16
68.8
0.5
> 16
Pip-Tazo
89.5
2
32
77.8
4
> 128
77.7
4
64
62.5
0.25
> 128
*E.
coli (28), K. oxytoca (10), K.
pneumoniae (8)
**na:
no CLSI or FDA breakpoints available
Conclusion: Based
on percent susceptibility, tigecycline, amikacin, and meropenem were the most
active agents against IAI Enterobacteriaceae, including those with an
ESBL phenotype. The antimicrobial susceptibility pattern observed among the two
non-enteric species underscore the need for IDSA recommended combination
therapies and continued monitoring of antimicrobial activities among these
clinical important microorganisms from IAIs in North America.
Douglas Biedenbach, MS1, Martha Renteria, MD1, Heidi Leister-Tebbe, BSN2 and Dan Sahm, PhD1, (1)International Health Management Associates, Inc., Schaumburg, IL, (2)Pfizer, Inc., Collegeville, PA
Disclosures:
D. Biedenbach,
IHMA, Inc.:
Independent Contractor
,
Research support
M. Renteria,
IHMA, Inc.:
Independent Contractor
,
Research support
H. Leister-Tebbe,
Pfizer, Inc.:
Employee
,
Salary
D. Sahm,
IHMA, Inc.:
Independent Contractor
,
Research support
Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.
Session: Poster Abstract Session: Antibacterial Susceptibility Surveillance