Primary total knee arthroplasty infected with Serratia marcescens

We report an unusual case of a Serratia marcescens infection of total knee arthroplasty 4 weeks after the procedure following aspiration carried out on the ward (contrary to local protocol). This was successfully treated with thorough wound debridement, irrigation, change of the polyethylene liner and systemic antibiotics using intravenous meropenem for 3 weeks followed by oral ciprofloxacin for another 3 weeks. Our patient made an uneventful recovery and there was no reported recurrence of infection at 8 months of follow-up. We are unsure as to whether the infection was introduced at the time of the joint aspiration or was a complication of the initial procedure despite all the standard aseptic measures taken at the time of surgery.