on the current study, when identification
of colonies from all culture-positive specimens was performed,
there were no PJI cases in which a second pathogen belonging to the
same genus was identified. Given that current IDSA and MSIS definitions
for periprosthetic tissue infection include isolation of the same microorganisms
from ≥2 specimens, we propose that all morphologically
dissimilar colonies should undergo MALDI-TOF MS testing (Osmon
et al., 2013; Parvizi et al., 2011). In the case of multiple specimens yielding
similar-appearing colonies, 2 should undergo MALDI-TOF MS testing.
If identical species are confirmed, thereby meeting the diagnostic
criteria for PJI, further workup of other culture-positive specimens
with morphologically identical colonies is unnecessary. Instead, their
identification may be referenced to those that have been identified
using MALDI-TOF MS (similarly to how antimicrobial susceptibility
data are referenced in many laboratories).