No abstract

The ASAT offers a web-enabled, version-controlled instrument for the assessment of antimicrobial stewardship in acute hospitals. It may offer a sensitive instrument to assess longitudinal progress on antimicrobial stewardship in an individual institution or act as a benchmark with similar organizations. Further work is ongoing to evaluate and further refine the ASAT.

This is the first study to use a standardized method for data collection and longitudinal analysis of antibiotic use in different hospitals. These data suggest that determination of changes in antibiotic exposure of hospital patients over a period of time is unreliable if only one clinical activity variable (such as OBDs) is used as the denominator. We recommend inclusion of admissions, OBDs and length of stay in statistical, time series analysis of antibiotic use. This model is also relevant to longitudinal analysis of infections in hospitals.

What is already known on this subject ► Flucloxacillin is a narrow-spectrum Grampositive antibiotic used for a number of serious infections in hospital including Staphylococcus aureus bacteraemia, skin and soft tissue infection, endocarditis and osteomyelitis. ► The frequency of dosing required for flucloxacillin to maintain therapeutic efficacy renders it unsuitable for most outpatient parenteral antimicrobial therapy (OPAT) services and there is a need for data on flucloxacillin stability in extended infusions to suit OPAT services. ► Flucloxacillin degrades rapidly in aqueous solutions during extended storage without chemical stabilisation. What this study adds ► The study presents data on the use of a citrate buffer to stabilise solutions of flucloxacillin (at concentrations 10-50 mg/mL) for up to 14 days at 2°C-8°C plus 24 hours at 32°C when reconstituted and diluted in a 0.3% w/v citratebuffered saline diluent with storage in two ambulatory device reservoirs (Accufuser and INfusor L). ► These data will support the use of extended infusions of flucloxacillin in OPAT services.

Objectives To investigate the stability of ceftolozane/tazobactam 5 mg/mL and 20 mg/mL solutions for infusion in two elastomeric devices: FOLFusor LV10 (Baxter Healthcare) and Easypump® II (B. Braun Medical Ltd) and determine if an extended shelf life of up to 8 days storage at 2–8°C plus 24 h ‘in use’ at 32°C was achievable. Methods Testing was as per the latest NHS Pharmaceutical Quality Assurance Committee Yellow Cover Document (YCD) requirements. A stability-indicating LC method was used for assessing the stability of solutions of ceftolozane/tazobactam at 5 mg/mL and 20 mg/mL (combined concentration of both actives) respectively, tested in two batches in triplicate (n = 3) at five timepoints according to the requirements of the YCD. Results Ceftolozane/tazobactam, diluted in 0.9% w/v sodium chloride at 5 mg/mL and 20 mg/mL, degraded during in-use storage at 32°C with <95% remaining after 18 h for some device/concentration combinations and all device/concentration combinations at 24 h, respectively. The data does support extended storage of up to 8 days at 2–8°C plus 12 h at 32°C ‘in-use’ when using either FOLFusor LV10 or Easypump® II devices and is compliant with YCD. Conclusions Solutions of ceftolozane/tazobactam can be administered in outpatient parenteral antimicrobial therapy (OPAT) services following refrigerated storage for up to 8 days, when limited to a 12 h infusion at in-use temperature of 32°C. For UK OPAT services where twice daily dosing is feasible, our data provides another treatment option for challenging infections. In countries where a 10% loss of ceftolozane/tazobactam is acceptable, a 24 h infusion is supported by the data.