[The first trial of OPAT (outpatient parenteral antimicrobial therapy) with continuous infusions in Japan].

OPAT (Outpatient Parenteral Antimicrobial Therapy) is widely utilized in various countries. Although once-daily parenteral antimicrobials are often prescribed in outpatient clinics, the term "OPAT" is not commonly used, and no well-organized OPAT practice has been reported in Japan. We implemented OPAT with continuous infusion using elastomeric infusion devices, which are commonly used in Australia and Singapore. We collected data about diseases, organisms, antimicrobials, treatment duration, bed days saved, outcome, readmission rate and cost reductions of all patients who were treated with OPAT with continuous infusions from July 2012 till June 2013. Ten patients (5 osteomyelitis, 4 abscess and 1 endocarditis) were treated and only one patient discontinued therapy due to the side effects of the antimicrobial. The most commonly targeted organism was Staphylococcus aureus. Cefazolin was the most frequently prescribed antimicrobial. The median OPAT days were 15 (range 4-29 days). Total bed days saved were 159. A peripherally inserted central catheter (PICC) was inserted for all patients and only one had to change the PICC during the treatment. Eight patients were cured and 2 were improved. No patient needed readmission. The estimated medical cost reduction was 1,655,930 yen, that is approximately 16,000 US dollars. Administration with continuous infusion makes it possible to continue the optimal parenteral antimicrobials for outpatients, which avoids prescribing unnecessary once-daily antimicrobials with a broader spectrum. Our experience shows OPAT with continuous infusion is safe and feasible practice not only for improving the QOL of patients but also for efficient bed utilization and medical cost savings.