Program Schedule

1400
Clinical and Microbiological Analysis of Staphylococcus lugdunensis isolates at UCLA

Session: Poster Abstract Session: Diagnostic Microbiology: Bacterial Infections
Saturday, October 11, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Posters
  • SLUG poster JV 9 25 14 pdf.pdf (1.1 MB)
  • Background: Staphylococcus lugdunensis (SLUG) can cause serious infection. SLUG is more often penicillin susceptible (PS) than other coagulase negative staphylococci. The Sanford Guide suggests penicillin as a treatment option for β-lactamase negative SLUG infection. This study evaluated antimicrobial susceptibility test (AST) results for SLUG isolated from 2008-2014. Retrospective review of clinical features and treatment decisions for 31 penicillin-susceptible (PS) and 31 penicillin- resistant (PR) SLUG was also performed. 

    Methods: AST was performed by Clinical and Laboratory Standards Institute broth microdilution and induced cefinase β-lactamase tests. Clinical features of 62 patients with cultures positive for SLUG were documented through retrospective chart review.

    Results: Among 574 SLUG isolates, the percentages susceptible were: 55% for penicillin, 94% for oxacillin, 99% for trimethoprim-sulfamethoxazole (T/S) and 100% for vancomycin. 
    Chart reviews for 62 patients revealed 22 had bacteremia, 1 osteomyelitis, 36 skin and soft tissue infections (SSTI). For the 16 patients with bacteremia and documented consolidative therapy, 10 were treated empirically with vancomycin, and 5 remained on vancomycin after AST was reported. 2 were de-escalated to oxacillin or cefazolin, and for 3, treatment was discontinued. Documented consolidative therapy (Table 1) for bacteremia included 1/4 with a PS isolate treated with ampicillin and 5/15 with an oxacillin-susceptible isolate treated with oxacillin or a 1st generation cephalosporin. In contrast, almost half of patients with SSTI were treated with oxacillin or a 1st generation cephalosporin, and a third with T/S.

    Table 1. Documented consolidative therapy for SLUG infections.

     

    No. patients ( % with susceptible isolates)

    Antimicrobial

    Bacteremia/Osteomyelitis (n=16)

    SSTI (n=30)

    Ampicillin

    1 (25)

    0 (0)

    Oxacillin / 1st gen ceph

    5 (31)

    12 (46)

    Vancomycin

    5 (30)

    0 (0)

    Ciprofloxacin

    3 (18)

    0 (0)

    T/S

    0 (0)

    10 (34)

    Other

    2 (n/a)

    8 (n/a)

    Conclusion: Disparity between AST results and penicillin and oxacillin utilization for the treatment of SLUG infections was found. Rapid identification and further education regarding penicillin and oxacillin susceptibility in SLUG may aid in expanded use of these antimicrobials for SLUG infections.

    Jennifer Veltman, MD1, Ian Mchardy, PhD2, Marissa Carvalho3, Anita Sokovic2, Myra Maldonado3, Janet Hindler4 and Romney M. Humphries, Ph.D.5, (1)Internal Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, (2)Pathology and Laboratory Medicine, UCLA, Los Angeles, CA, (3)UCLA Pathology & Laboratory Medicine, Los Angeles, CA, (4)Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA, (5)Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA

    Disclosures:

    J. Veltman, None

    I. Mchardy, None

    M. Carvalho, None

    A. Sokovic, None

    M. Maldonado, None

    J. Hindler, None

    R. M. Humphries, Affinity Biosensors: Investigator, Research support

    Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

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