Apparent increased prevalence of high-level aminoglycoside-resistant Enterococcus durans resulting from false identification by a semiautomated software system.

Identification of enterococci by using a semiautomated system (PASCO; Difco Laboratories, Detroit, Mich.) in the AHEPA University Hospital, Thessaloniki, Greece, revealed a high proportion of Enterococcus durans, particularly among isolates highly resistant to gentamicin and streptomycin. When 14 isolates were further tested by a conventional biochemical scheme and by PCR, all were reidentified as Enterococcus faecalis. Antibiotic resistance and pulsed-field gel electrophoresis patterns showed that unrelated strains were misidentified.