204. Case series of daptomycin nonsusceptible Enterococcus infections with no prior daptomycin exposure in a tertiary center
Session: Poster Abstract Session: Antimicrobial Resistance: Clinical Studies
Friday, October 21, 2011
Room: Poster Hall B1
Background: 

Data on the potential emergence of daptomycin nonsusceptibility among enterococci remain limited especially in cases with no prior exposure to daptomycin.

Methods: 

We retrospectively reviewed 9 cases of infection associated with DNSE (defined as daptomycin minimal inhibitory concentration [MIC] >4 ug/ml by the Clinical Laboratory Standards Institute [CLSI], 2003) with no prior history of receipt of daptomycin identified at a tertiary center from January 2007-March 2011. Cases were evaluated for possible risk factors for acquisition of DNSE, susceptibility to antimicrobials, microbiologic and clinical success.

Results: 

Of the 9 cases, there were 3 bloodstream (33.3%), 3 intraabdominal (33.3%), 2 urinary tract (22.2%), and 1 soft tissue infections (11.1%). Six patients (66.7%) were male. The mean age of patients was 58.9 years (range, 26-75 years).  Recent surgery (<3 months), immunosuppression, and hospitalization for >30 days were observed in 5 (55.6%), 7 (77.8%), and 3 patients (33.3%), respectively. Five isolates were available for strain typing and were found to be unrelated. Recent exposure to antimicrobials within the prior 3 months, including vancomycin, anaerobic agents and third generation cephalosporins was documented in 6 of 9 (66.7%) cases. Three (33%) cases had no recent exposure to antimicrobials. Four patients had DNSE isolated on the first day of hospitalization and had no hospitalization in the prior 12 months consistent with community acquisition of DNSE. Four (44.4%) of the cases were treated with linezolid while vancomycin, quinupristin/dalfopristin and piperacillin/tazobactam were used in 2 (22.2%), 1 (11.1%) and 2 (22.2%), respectively. Four patients (44.4%) expired.

Conclusion: 

Enterococcal resistance to daptomycin can occur without prior daptomycin exposure or hospitalization. To our knowledge, this is the largest case series of DSNE isolates among patients with no prior exposure to daptomycin. Daptomycin is one of a limited number of antimicrobials with activity against vancomycin-resistant enterococci. Case-control studies are needed to determine risk factors associated with development of DNSE infections.


Subject Category: A. Antimicrobial agents and Resistance

Theodoros Kelesidis, MD, Ronald Reagan UCLA Medical Center, Los Angeles, CA, Romney Humphries, Ph.D., Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA and David Pegues, MD, University of California, Los Angeles, Los Angeles, CA

Disclosures:

T. Kelesidis, None

R. Humphries, None

D. Pegues, 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.