Study results showed a high rate of resistance to aminoglycoside antibiotics in chronic periprosthetic gram-positive cocci infections, with increases after failed staged-exchange arthroplasties in which aminoglycoside-cement spacers were used.
Researchers retrospectively compared aminoglycoside susceptibility profiles for 133 patients with gram-positive cocci (GPC) isolations at the time of reoperation following chronic hip or knee periprosthetic joint infections. Patients were categorized into groups based on whether aminoglycoside-cement spacers (A-CSs) were used previously.
At the time of reoperation following a total knee or total hip chronic infection, patients had a total of 147 GPC isolations, of which 72.8% were Coagulase-negative Staphylococcus.
The researchers found 76.8% of prostheses were infected by a single GPC species, and 19.8% were infected by a combination of two GPC microorganisms.
Thirty-two percent of all isolates were resistant to gentamicin, 40.6% to tobramycin and 21.4% of the 145 gram-positive isolates were resistant to rifampicin.
Patients who had previous A-CS experienced a significantly higher rate of resistance with gentamicin and tobramycin compared with patients with no previous A-CS use, according to the researchers.
Disclosure: The authors have no relevant financial disclosures.