1597. Epidemiology of ESBL-Producers in Intra-Abdominal Infections in Adults in ICU versus non-ICU wards in North America: SMART 2010-2012
Session: Poster Abstract Session: Multidrug-Resistant Gram Negative Rods
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: ICU admission has been identified as a risk factor for extended-spectrum β-lactamase  (ESBL) infections, especially in Klebsiella .This report from the Study for Monitoring Antimicrobial Resistance Trends (SMART) summarizes the occurrence of ESBL producers in IAI in 2010-2012 in North America (NA), comparing ICU and non-ICU wards.

Methods: 29 sites in the US and Canada collected up to 100 consecutively isolated gram-negative pathogens (GNP) from adults with IAI per year. Susceptibility and ESBL phenotypes were determined by microdilution per CLSI and plate manufacturer guidelines for 4,249 GNP. An IAI was defined as hospital-associated (HA) or community-associated (CA) if cultured ≥48 hours or <48 hours post admission, respectively. ESBL rates were compared with the Fisher exact test.

Results:

Escherichia coli, K. pneumoniae, Proteus mirabilis, and K. oxytocacomprised 64% of all IAI GNP. Prevalence rates of each species and ESBL rates are shown below:

 

ICU wards

 

Non-ICU wards

 

HA

CA

Total

 

HA

CA

Total

All organisms

n

471

343

814

1640

1795

3435

E. coli

n

167

136

303

623

743

1366

Prevalence (%)

35.5

39.7

37.2

38.0

41.4

39.8

ESBL+ rate (%)

12.0*

2.9*

7.9

10.9

7.4

9.0

K. pneumoniae

n

77

66

143

271

331

602

Prevalence (%)

16.3

19.2

17.6

16.5

18.4

17.5

ESBL+ rate (%)

11.7

9.1

10.5

11.1

7.3

9.0

P. mirabilis

n

15

14

29

44

86

130

Prevalence (%)

3.2

4.1

3.6

2.7

4.8

3.8

ESBL+ rate (%)

0

0

0

6.8

1.2

3.1

K. oxytoca

n

11

15

26

61

77

138

Prevalence (%)

2.3

4.4

3.2

3.7

4.3

4.0

ESBL+ rate (%)

9.1

6.7

7.7

4.9

5.2

5.1

* HA and CA significantly different (p<0.05).

Note: Differences between ICU and non-ICU wards not significant (p>0.05).

Conclusion:

  • While higher ESBL rates in ICU than non-ICU wards have been reported elsewhere, our results for IAI GNP showed no significant differences in NA.
  • Clearer differences are seen between HA and CA infections, with ESBL rates tending to be higher in HA IAI in both ICU and non-ICU settings (but only statistically significant for E. coli in ICUs).
  • These results concur with a 2004 CDC National Nosocomial Infections Surveillance report with similar rates of K. pneumoniae and E. coli resistant to 3rd gen. cephalosporins in US ICU and non-ICU wards. Although ICU admission has been reported to be a risk factor for ESBL infection, our data suggest that may not be the case in NA.
Sibylle Lob, MD, MPH1, Robert Badal, B.S.1, Daryl Hoban, PhD1, Samuel Bouchillon, MD1, Meredith Hackel, PhD, MPH1, Douglas Biedenbach, BS1, Stephen Hawser, PhD2 and Ian Morrissey, PhD2, (1)International Health Management Associates, Inc., Schaumburg, IL, (2)IHMA Europe SÓrl, Epalinges, Switzerland

Disclosures:

S. Lob, Merck & Co., Inc.: Research Contractor,

R. Badal, Merck & Co., Inc.: Research Contractor,

D. Hoban, Merck & Co., Inc.: Research Contractor and Speaker's Bureau, Grant recipient and Salary from IHMA, which receives grant from Merck

S. Bouchillon, Merck & Co., Inc.: Research Contractor, Salary from IHMA, which receives grant from Merck

M. Hackel, Merck & Co., Inc.: Research Contractor, Salary from IHMA, which receives grant from Merck

D. Biedenbach, Merck & Co., Inc.: Research Contractor, Salary from IHMA, which receives grant from Merck

S. Hawser, Merck & Co., Inc.: Research Contractor, Salary from IHMA, which receives grant from Merck

I. Morrissey, Merck & Co., Inc.: Research Contractor, Salary from IHMA, which receives grant from Merck

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