Clinical and microbiological characteristics of six Staphylococcus pettenkoferi isolates from blood samples

Coagulase-negative staphylococci (CoNS) are reported to be the leading cause of nosocomial bloodstream infections. Staphylococcus pettenkoferi is a novel member of CoNS that was first isolated from the human blood and bursitis wound in 2002. We have reported cases of 6 S. pettenkoferi strains isolated from blood specimens, including one pathogen and 5 contaminants and catheter colonizers. Brucker Biotyper (Brucker Daltonics, Bremen, Germany) and molecular typing with 16S rRNA gene sequencing confirmed the 6 isolates as S. pettenkoferi. The conventional phenotypic identification of these isolates is not reliable owing to their inconsistent biochemical characteristics. Five of the 6 isolates were found to be resistant to oxacillin, and all isolates showed susceptibility to vancomycin and linezolid. For accurate identification of this novel species, advanced methods by using Brucker Biotyper or molecular methods such as 16S rRNA gene sequencing are required.