207. Risk Factors for Linezolid (LZD) and Vancomycin-Resistant Enterococci: a Case-Case Control Study
Session: Poster Abstract Session: Antimicrobial Resistance: Clinical Studies
Friday, October 21, 2011
Room: Poster Hall B1
Background: Risk factors specifically associated with the isolation of LZD-resistant (LZD-R) VRE were evaluated.

Methods: A case-case control study was conducted to identify independent risk factors for LZD-R VRE. Unique patients with LZD-R VRE from 2008-09 were matched to cases of LZD-susceptible (LZD-S) VRE and to uninfected controls in a 1:1:3 ratio. 

Results: 20 LZD-R VRE cases (12 E. faecium, 8 E. faecalis; 13 from urine, 5 from wounds, 2 from blood) were identified (1.3% of 1519 VRE patients) and matched to 20 LZD-S VRE cases and 60 uninfected controls. The mean age of the study cohort was 62.9±15.5 years, 41 (41%) were male, and 35 (35%) resided in institutions prior to admission. In bivariate analysis, the following variables were associated with isolation of both LZD-R and LZD-S VRE (P<0.05 compared to controls): permanent devices, chronic skin ulcer, immunosuppression, co-colonization with MRSA (within 7 days of VRE isolation), and any recent antibiotic exposure. Neurologic diseases, and ICU stay in the past 3 months were associated with LZD-R but not LZD-S VRE isolation (P<0.05 compared to controls). In multivariate analysis after controlling for Charlson score, independent risk factors associated with isolation of LZD-R and LZD-S VRE were determined (Table). Exposure to prior LZD occurred in 2 patients with LZD-R, 1 with LZD-S VRE and 1 control.

Conclusion: Prior surgery, immunosuppressive status, and exposure to β-lactam antibiotics were uniquely associated with isolation of LZD-R VRE.

Table: Multivariate analysis of risk factors for the isolation of LZD-R and LZD-S VRE

Variable

LZD-R VRE cases vs uninfected controls, Odds ratio (95% CI)

LZD-S VRE cases vs uninfected controls, Odds ratio (95% CI)

Permanent devices on admission

17.15 (1.33-221.58) 4.12 (1.16-14.69)

Invasive procedures in the past 3 months

9.35 (1.04-84.28) 6.60 (1.31-33.35)
Any antibiotics exposure in the past 3 months 12.47 (1.50-103.89) 27.57 (3.24-234.55)
Surgery in the past 3 months 12.37 (1.41-108.27)

Exposure to β-lactam antibiotics in the past 3 months

7.59 (1.38-41.70)
Immunosuppressive status on admission* 13.54 (1.10-167.36)

*Any of the followings: neutropenia, steroid use, anti-TNF therapy, chemotherapy, radiotherapy, post-transplantation.


Subject Category: A. Antimicrobial agents and Resistance

Kayoko Hayakawa, MD, PhD1, Dror Marchaim, MD1, Jason Pogue, PharmD1, Bharath Sunkara, MD1, Kevin Ho, MS1, Kavyashri Kodlipet Jagadeesh, MD1, Srinivasa Kamatam, MD1, Shakila Parveen, MD1, Priyanka Nanjireddy, MD1, Vicki Collins, MD1, Paul Lephart, PhD2, Emily Martin, MPH, PhD1, Michael Rybak, PharmD, MPH1 and Keith Kaye, MD, MPH, FIDSA1, (1)Detroit Medical Center / Wayne State University, Detroit, MI, (2)DMC University Laboratories, Detroit, MI

Disclosures:

K. Hayakawa, None

D. Marchaim, None

J. Pogue, None

B. Sunkara, None

K. Ho, None

K. Kodlipet Jagadeesh, None

S. Kamatam, None

S. Parveen, None

P. Nanjireddy, None

V. Collins, None

P. Lephart, None

E. Martin, None

M. Rybak, None

K. Kaye, None

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.