Corynebacterium striatum: a multidrug-resistant emerging pathogen

Abstract number: R2337

Pini B., Brigante G., Aso-Taunta E., Vardopoulou A., Luzzaro F., Toniolo A.

Objectives:Corynebacterium striatum is a Gram-positive organism that commonly colonizes the skin and mucous membranes. Over the last few years, this organism has been increasingly recognised as a cause of wound and low respiratory tract infections. The aim of the study was to evaluate epidemiology and antimicrobial susceptibility of C. striatum clinical isolates collected at our laboratory in 2006 and 2007.

Methods: Isolates of C. striatum obtained from routine specimens were characterised at the Microbiology Laboratory of the Ospedale di Circolo (Varese, Italy). Identification was achieved using the BBL Crystal Gram-Positive ID system (Becton Dickinson Diagnostic Systems, Sparks, MD). Antimicrobial susceptibility was quantitatively evaluated by the Etest method (AB Biodisk, Solna, Sweden). Results were interpreted according to the M45-A document (Clinical and Laboratory Standards Institute, 2006).

Results: Overall, 128 isolates were obtained during the two-year period, most of them from skin and soft tissue specimens (76.5%), but also from vascular catheter (8.6%), low respiratory tract (6.2%), and blood (3.1%). Strains were frequently isolated from aged and/or compromised patients admitted to different wards. The majority of isolates were characterised by multi-drug resistance, including penicillin, gentamicin, erythromycin, tetracyclines, expanded-spectrum cephalosporins, and ciprofloxacin. Teicoplanin and vancomycin as well as newer antimicrobial agents (linezolid, daptomycin, and quinupristin-dalfopristin) were consistently active in vitro against C. striatum isolates.

Conclusion:C. striatum should be considered an emerging multidrug-resistant nosocomial pathogen in aged/compromised patients and in long-term hospitalised patients. Drugs recently introduced to treat skin and soft tissue infections appear to represent an effective therapeutic option in order to limit the use of glycopeptides.