# Effect of oral antibiotics after two-stage revision for periprosthetic joint infection on subsequent antibiotic resistance within a national cohort of United States veterans

## TL;DR

Long-term oral antibiotics after joint infection surgery may increase antibiotic resistance in future infections, according to a study of U.S. veterans.

## Contribution

This study is the first to show that prolonged oral antibiotics after joint surgery increases resistance to certain antibiotics in future infections.

## Key findings

- Bacteria in recurrent infections were more resistant to tetracyclines and sulfamethoxazole in patients on prolonged antibiotics.
- No increased resistance was found for beta-lactams or fluoroquinolones.
- No difference in infection recurrence or death was observed between groups.

## Abstract

Background: Prior studies have indicated that administration of prolonged courses of oral antibiotics after Stage 2 reimplantation surgery for periprosthetic joint infection (PJI) results in a lower rate of recurrent PJI. However, there is concern that this antibiotic usage results in an increased risk of antibiotic resistance in any subsequent PJI that does occur.

Methods: We retrospectively reviewed patients who underwent Stage 2 reimplantation surgery for PJI within the national Veterans Affairs hospital system of the United States. We compared those who received at least 2 weeks of oral antibiotics after Stage 2 reimplantation to those who did not. The primary outcome was the proportion of organisms resistant to four classes of antibiotics (tetracyclines, fluoroquinolones, oral beta-lactams, and sulfonamides) in recurrent PJI. Secondary outcomes included recurrent PJI and death.

Results: Of the 605 patients who underwent Stage 2 reimplantation for PJI, 154 patients received at least 14 d of antibiotics after surgery and 451 patients did not. Bacteria causing recurrent PJI in patients who received prolonged antibiotics were more likely to be resistant to tetracyclines and trimethoprim–sulfamethoxazole but not oral beta-lactams or fluoroquinolones. There was no difference in risk of recurrent PJI or death between the two groups.

Conclusions: Prolonged oral antibiotic treatment after Stage 2 reimplantation increases the risk of antibiotic resistance to some antibiotics in subsequent PJI. We recommend further research to identify the best choice of antibiotic and duration after Stage 2 reimplantation, to maximize benefits while minimizing risks.