Impact of Antibiotic Exposure Duration on Pathogen Detection in Periprosthetic Joint Infection

Antibiotic exposure affects pathogen detection in periprosthetic joint infection (PJI). This study evaluated the impact of antibiotic duration before sampling on the diagnostic performance of microbiological cultures and metagenomic next-generation sequencing (mNGS).

We conducted a retrospective analysis of 153 patients with PJI treated at our center between January 2013 and March 2024. Patients who had discontinued antibiotics for at least 7 days before sampling and those with no history of antibiotic use were classified into the antibiotic-withdrawal group (AWD group). Based on the duration of antibiotic exposure, those who received antibiotics for ≤7 days before sampling was assigned to the short-term antibiotic group (STA group), while those with >7 days of continuous antibiotic use were included in the long-term antibiotic group (LTA group). By comparing microbiological culture and mNGS results across these groups, we analyzed how antibiotic duration before sampling affects etiological diagnosis in PJI patients.

In the AWD group, microbial culture positivity (86.3%, 44/51) was comparable to mNGS (92.2%, 47/51; P=0.338). However, mNGS demonstrated superior positivity rates in both the STA (86.7% vs 70.0%, P=0.027) and LTA groups (76.2% vs 54.8%, P=0.039). Prolonged antibiotic use (>7 days) markedly reduced culture positivity (86.3% to 54.8%, P=0.001), whereas the decline in mNGS sensitivity was smaller (92.2% to 76.2%, P=0.032), indicating its greater resistance to antibiotic effects. Among culture-negative PJI cases, mNGS maintained robust diagnostic performance across all groups (CN-AWD: 57.1%; CN-STA: 66.7%; CN-LTA: 57.9%), with no significant differences observed.

Antibiotic use before sampling significantly impacts PJI pathogen detection. We recommend either: (1) sampling after ≥7 days without antibiotics, or (2) for patients on prolonged antibiotics (>7 days), combining microbial culture with routine mNGS to improve diagnostic accuracy.