1406. A case-control study of risk factors and outcomes for isolation of CTX-M extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in a large U.S. medical center
Session: Poster Abstract Session: Epidemiology of Multiple Drug-Resistant Gram Negative Rods
Saturday, October 20, 2012
Room: SDCC Poster Hall F-H

Background : CTX-M type ESBLs are replacing more traditional TEM and SHV type ESBLs in ESBL-producing E.coli (ESBLEC). We conducted a case-control study to identify independent risk factors for recovery of CTX-M type ESBLEC (CTXMEC), in a large U.S. medical center located in southeast Michigan.

Methods : Unique cases with clinical ESBLEC isolation during the study period (2/2010 –7/2011) were included. PCR analysis for the detection of CTX-M β-lactamase genes was conducted. Patients with CTXMEC whose detailed medical records were available (cases) were matched to uninfected controls  in a 1:1 ratio.

Results : 319 CTXMEC cases were identified from urine (n=241), wounds (n=32) sputum (n=22) and blood (n=22) and were matched to 319 uninfected controls. In 247 (77.4%) cases, CTXMEC was present at the time of hospital admission. The mean age of the study cohort was 64±17.9 years and 305 (47.8%) were male. Independent risk factors for the isolation of CTXMEC were determined (Table). In-hospital mortality rates were higher in CTXMEC group, although this was not statistically significant (5.7% vs 3.8%, p=0.08). Median total length of stay was greater among CTXMEC cases than controls (7 [IQR: 4-12] vs 4 [2-6], p<0.001). CTXMEC cases were more frequently discharged to long-term care facilities after being admitted from home (18.6% vs 3.5%, p<0.001), and were more frequently re-admitted within 6 months after discharge (58.6% vs 41.7%, P<0.001) than were controls.

Conclusion :  Exposure to oxyimino-cephalosporins and history of urinary tract infection or catheter use were independently associated with isolation of CTXMEC.  Utilization of healthcare resources was greater among CTXMEC cases than controls.

Table. Multivariate Analysis of Risk factors for the isolation of CTX-M-ESBL E.coli A


CTX-M-ESBL E.coli cases vs uninfected controls

Odds ratio

(95% CI)

Indwelling urinary catheter B

4.1 (2.0-8.2)

History of UTI

3.3 (1.7-6.3)

Oxyimino-cephalosporins C in the past 3 months

3.2 (1.4-7.4)

Dependent functional status on admission

2.5 (1.4-4.6)

Non-home residence

2.5 (1.3-4.8)

Charlson combined comorbidity index (≥5)

2.3 (1.3-3.9)

A Controlled for vancomycin exposures in the past 3 months.

B For cases, at time of at CTXMEC isolation; for controls at time of admission.

C Includes ceftriaxone, cefepime, ceftazidime.

Kayoko Hayakawa, MD, PhD1, Sureka Gattu2, Dror Marchaim, MD1, Harish Pulluru, MBBS1, Moumita Sarkar, MD1, Shah Mohin, MBBS1, Meenakshi Dasagi, BDS1, Swetha Reddy, MBBS1, Satya Marrey, MBBS, MPH1, Vedavyas Gannamani, MBBS1, Nandhini Madhanagopal, MBBS1, Srinadh Annangi, MBBS1, Busani Sudha, MBBS1, Kalyan Srinivas Muppavarapu, MBBS, MPH1, Pranathi Rao Sundaragiri, MBBS1, Hari Kakarlapudi, MBBS1, Priyanka Nanjireddy, MBBS1, Ashish Bhargava, MD1, Paul Lephart, PhD3, Jason Pogue, PharmD1, Karen Bush, PhD2 and Keith Kaye, MD, MPH, FIDSA, FSHEA1, (1)Detroit Medical Center (DMC) / Wayne State University, Detroit, MI, (2)Indiana University, Bloomington, IN, (3)Detroit Medical Center/ Wayne State University, Detroit, MI


K. Hayakawa, None

S. Gattu, None

D. Marchaim, None

H. Pulluru, None

M. Sarkar, None

S. Mohin, None

M. Dasagi, None

S. Reddy, None

S. Marrey, None

V. Gannamani, None

N. Madhanagopal, None

S. Annangi, None

B. Sudha, None

K. Srinivas Muppavarapu, None

P. Rao Sundaragiri, None

H. Kakarlapudi, None

P. Nanjireddy, None

A. Bhargava, None

P. Lephart, None

J. Pogue, None

K. Bush, None

K. Kaye, pfizer: Consultant, Grant Investigator and Speaker's Bureau, Consulting fee, Research grant and Speaker honorarium
merck: Consultant, Grant Investigator and Speaker's Bureau, Consulting fee, Research grant and Speaker honorarium
cubist: Consultant, Grant Investigator and Speaker's Bureau, Consulting fee, Research grant and Speaker honorarium
theradoc: Consultant, Consulting fee

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