Prolonged incubation time unwarranted for acute periprosthetic joint infections

Current laboratory protocols for periprosthetic joint infections (PJIs) involve a standard 10- to 14-day incubation period. However, recent evidence indicates considerable variability in the time to diagnosis (TTD) between acute and chronic PJIs. TTD is also influenced by the employed culture media and sample types. Enriched liquid media, such as broths and blood culture bottles, along with sonication fluid culture, are commonly used, though their incremental benefit for PJI diagnosis remains debated. We retrospectively analyzed 187 confirmed hip and knee PJIs, each with at least three intraoperative samples. Comparison of TTD among early acute (n = 68), late acute (n = 52), and late chronic (n = 67) PJIs revealed a significant difference, particularly between late acute and late chronic infections (P < 0.004). Early acute and late acute PJIs were diagnosed within 5 days in 97.1% and 98.1% of cases, respectively, contrasting with 14 days required for 97.1% of late chronic PJIs. Enriched liquid media significantly improved species detection, especially in polymicrobial and anaerobic infections. Pediatric and anaerobic blood culture bottles demonstrated superior efficacy over thioglycolate broths for diagnostic confirmation. Sonication fluid culture was essential for confirming diagnoses in 17.6% of cases. Our findings highlight that clinical presentation, rather than time since primary arthroplasty, should guide incubation duration: both early acute and late acute PJIs can be diagnosed within 5 days. Medical microbiology laboratories should consider shorter incubation times for acute PJIs to optimize diagnostic efficiency. The use of blood culture bottles and sonication fluid culture proves invaluable for accurate PJI diagnosis.

While molecular techniques are becoming increasingly employed, culture remains the gold standard for diagnosing periprosthetic joint infections. However, guidance for laboratory protocols is limited and highly variable. This article aims to increase diagnostic efficiency by providing concrete recommendations for medical microbiology laboratories.