Staphylococcus warneri is a coagulase negative Staphylococcus (CNS) commonly present in the flora
of human epithelia and mucosal membranes. Over the last two decades, similarly to other CNS species,
S. warneri has been reported as a new emerging pathogen, capable of causing serious infections
usually in association with the presence of implant materials, but, at times, even in the absence
of a foreign body and in patients considered immunocompetent. At present, there is still a lack of
scientific data on the pathogenesis and epidemiology of this species. The present study investigated
a collection of 26 clinical isolates derived from orthopedic infections, some associated with implant
materials and others not. Automated ribotyping showed the existence of 5 distinct ribogroups. Except
for the least numerous ribogroup consisting of a single isolate, all other ribogroups included at least
one strain obtained from an infection not associated with implant materials, suggesting that putative
virulence factors necessary for infections even in the absence of a foreign body could be transversal
to most ribogroup categories. Orthopedic infections were found to involve S. warneri strains with low
antibiotic resistance potential, differing in this respect from the strains isolated at neonatal intensive
care units, where this species has been described to figure among the principal causative agents and
exhibit an alarming profile of antibiotic resistance