Fracture-Related Tibial Infection Due to Nocardia abscessus After Agricultural Trauma: A Case Report

INTRODUCTION
• Fracture-Related Infections (FRI) due to Nocardia spp. are rare and often overlooked following an open trauma due to its slow growth.
• We describe the case of a polymicrobial osteoarticular FRI in which Nocardia abscessus was isolated, following an agricultural machinery accident, highlighting the diagnostic the diagnostic work-up, surgical management, and antimicrobial strategy that was employed.
• A retrospective review of this single case was conducted, analysing the clinical data, imaging, operative findings, microbiology, treatment course, and short-term outcomes.

CASE DESCRIPTION
Autonomous male patient in his late 80s. No relevant medical history.
Mechanism of lesion: Gustilo grade III open segmental fracture of the right tibia after agricultural trauma.
Initial surgical treatment:
- At admission: Emergency
debridement + external fixation assembly with Hoffman kits.
- At 2 weeks: Removal of the fixator and intramedullary nailing with T2 Alpha nail (Skyler).

Post-op complications (3weeks later)
• New onset of fever, knee pain and local inflammatory sings, > inflammatory
markers;
• CT scan: a large suprapatellar effusion, hemarthrosis, intra-articular gas, and adjacent soft-tissue oedema;
• Surgical approach: debridement and retention of intramedullary nail. Multiple deep samples obtained intraop.
   - Microbiology Lab Notification: Enterobacter cloacae complex and Nocardia abscessus growth.
• Empirical ABx started after sample collection.

Antimicrobial strategy (6 months total)
Empirical ABx approach (5d):
  ✓ Pip-tazo PLUS ✓ Vancomycin
Targeted ABx approach during hospitalization:
  ✓ Ceftriaxone (8-day course ab initio) PLUS ✓ Imipenem/c (4wks) PLUS ✓ High-dose TMP-SMX (4wks)
Oral stepdown in outpatient care:
  ✓ Ciprofloxacin (2wks) PLUS ✓ TMP –SMX (6 mos.)

Clinical outcomes with prolonged targeted therapy:
  ✓ Sustained apyrexia and decreased inflammatory markers.
  ✓ Limb preservation with medullary retainment.
  ✓ Partial functional recovery after surgery:
      → At week 2 post debridement: able to help in transfer from bed to chair;
      → At week 4 post debridement: able to walk with assistance.

CONCLUSIONS
• Nocardia spp. should be considered in FRI cases following contaminated open agricultural trauma, particularly when microbiology is
unusual or evolution is protracted.
• This case illustrates the importance of repeated surgical debridement, deep microbiological sampling, prolonged targeted combination therapy, and systematic exclusion of dissemination.
• Despite polymicrobial infection and major comorbidity, limb-preserving management with retention of osteosynthesis material may be feasible in selected patients.

Key Message: Nocardia abscessus should be considered in polymicrobial FRI following agricultural trauma. Limb-preserving outcomes are achievable with early diagnosis, repeated debridement, deep microbiological sampling, and prolonged targeted combination therapy.