1433. Phenotypic and Genotypic Changes Over Time and Across Facilities of Serial Colonizing Escherichia coli Isolates Recovered from Injured Service Members
Session: Poster Abstract Session: Epidemiology of Multiple Drug-Resistant Gram Negative Rods
Saturday, October 20, 2012
Room: SDCC Poster Hall F-H
Background: Service members injured during deployment who arrive at Military Treatment Facilities (MTF) undergo systematic screening for multidrug-resistant (MDR) bacteria colonization to decrease possible nosocomial transmission. Escherichia coliis one of the most common organism isolated. Evaluating these colonizing isolate’s phenotypic and genotypic changes over time and across MTFs enables a better understanding of transmission patterns and infection control strategies.

Serial admission and in hospital surveillance MDR and non-MDR groin E. colicolonizing isolates from patients evacuated from Iraq and Afghanistan and transitioning thru Germany were collected at Landstuhl Regional Medical Center (MC), National Naval MC, Walter Reed Army MC and Brooke Army MC between June 2009 and May 2011. Isolates underwent automated antimicrobial susceptibility testing and pulsed-field gel electrophoresis to determine resistance profiles and clonality (defined by 85% similarity).

Results: 235 isolates (102 non-ESBL, 133 ESBL- producing, 18 Iraq, 217 Afghanistan) from 91 patients (6 Iraq, 85 Afghanistan) were characterized. 37 (41%) patients were colonized with ESBL-producing isolates only, 32 (35%) with non-ESBL only, and 22 (24%) with both. 128 pulsed-field types (PFTs) were detected. Serial isolates from only 10 (11%) patients showed increasing antibiotic resistance over time and MTFs with no class specific changes. No increase in ESBL-producers was noted.

Number of serial isolates per

patient per MTF

N = patients (%)


One PFTs*

Multiple PFTs*

2 isolates / 2 MTF


44 (79)

12 (21)

3 isolates / 2 MTF


4 (20)

16 (80)

4 isolates / 2 MTF


1 (10)

9 (90)

5 isolates / 2 MTF



2 (100)

6 isolates / 2 MTF



1 (100)

3 isolates / 3 MTF



1 (100)

4 isolates / 3 MTF



1 (100)



49 (54)

42 (46)

*Comparing serial isolates of individual patients

Conclusion: There was a large variety of colonizing E. coli isolates with a high percentage of ESBL-producing isolates. The number of multiple PFTs in individual patients increased with increasing numbers of serial isolates. An increase in new colonizing E. coli isolates was noted when patients were admitted to a second MTF possibly due to nosocomial transmission or antimicrobial pressure.

Katrin Mende, PhD1,2, Miriam Beckius, MPH1, Wendy Zera, BS1,2, Xin Yu, MS1, Kristelle Cheatle, BA1, Michael Landrum, MD1,2, Katrina Crawford, MS2, Amy Weintrob, MD2, David Tribble, MD, DrPH2, Glenn Wortmann, MD3, Bradley Lloyd, DO4, Clinton K. Murray, MD5 and the IDCRP TIDOS Investigative Team, (1)San Antonio Military Medical Center, Fort Sam Houston, TX, (2)Infectious Disease Clinical Research Program, Uniformed Services University of the Health Sciences, Bethesda, MD, (3)Walter Reed National Military Medical Center, Bethesda, MD, (4)Landstuhl Regional Medical Center, Landstuhl, Germany, (5)San Antonio Military Medical Center, Ft Sam Houston, TX


K. Mende, None

M. Beckius, None

W. Zera, None

X. Yu, None

K. Cheatle, None

M. Landrum, None

K. Crawford, None

A. Weintrob, None

D. Tribble, None

G. Wortmann, None

B. Lloyd, None

C. K. Murray, None

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