Phenotypic characteristics of 31 strains of Corynebacterium striatum isolated from clinical samples

During a 34-month period (January 1991 to October 1993), 31 Corynebacterium striatum stains recovered from clinical samples from 24 patients were characterized. Twenty (64%) strains were isolated from wound exudates, 5 (16%) were isolated from bronchial aspirates, 2 (7%) were isolated from urine, 2 (7%) were isolated from endotracheal tubes, 1 (3%) was isolated from a catheter, and 1 (3%) was isolated from empyema. The organisms were identified by conventional culture and phenotypic characterization, the API CORYNE system, and cellular fatty acid composition analyses. The colonies of C. striatum could be confused with those of coagulase-negative staphylococci upon primary isolation from clinical material. A consistent phenotypic pattern was observed: all strains reduced nitrate, hydrolyzed tyrosine, and produced acid from glucose, fructose, and sucrose but not from maltose. API CORYNE profile numbers were 3100105 (28 strains) and 3000105 (3 strains). Susceptibility testing of C. striatum was performed by disk diffusion. All strains were susceptible to both imipenem and vancomycin and resistant to fosfomycin; most strains were susceptible to ampicillin and cephalosporins and resistant to clindamycin, erythromycin, and tetracycline. Performing a Gram stain of fosfomycin-resistant "Staphylococcus-like" colonies was critical in order to identify C. striatum.