Chronic periprosthetic hip infection: micro-organisms responsible for infection and re-infection

Area of Science:

• Orthopedic surgery
• Infectious disease microbiology

Background:

• Periprosthetic joint infection (PJI) is a significant complication following total hip arthroplasty (THA).
• Accurate identification of causative microorganisms is essential for effective treatment and management of infected THA, especially during revision surgery.

Purpose of the Study:

• To identify microorganisms causing first-time revision for infected THA.
• To compare pre-operative and intra-operative microbiological findings.
• To analyze intra-operative findings against microorganisms responsible for re-infection.

Main Methods:

• Microbiological analysis of pre-operative and intra-operative samples from 73 patients undergoing revision THA or resection arthroplasty.
• Patients were categorized into two-stage revision THA (43 patients) or modified resection arthroplasty (30 patients).
• Identification of microbial species in cases of re-infection (29 cases).

Main Results:

• Pre-operative and intra-operative microbial findings coincided in 50.7% of cases.
• Bacterial growth was detected in 98.5% of intra-operative tests.
• Staphylococcus species were the predominant pathogens, identified in 48% as single genus infections and 45% as associations. Gram-negative infections occurred in 5.5% of cases.
• Re-infection rates were 23.2% in two-stage revision THA and 63.3% in resection arthroplasty. Staphylococcus species were implicated in 19 of 29 re-infection cases.

Conclusions:

• Intra-operative microbiological tests during first-time revision THA provide a reliable spectrum of microorganisms.
• These findings aid in assessing antibiotic resistance, developing treatment protocols, and determining prognosis.
• Preventive measures for primary THA and strategies against PJI and re-infection should primarily target staphylococci.