ESAC point prevalence methodology to assess antimicrobial consumption and quality of prescribing in an Australian setting

To the Editor: Point prevalence studies have been used for many years as markers of antimicrobial consumption,1,2 but they have suffered from a lack of standardisation with regard to the populations studied and the data collected. These deficiencies make it difficult to generalise the data outside the study populations. In recent years, the European Surveillance of Antimicrobial Consumption (ESAC) has sought to overcome these weaknesses by implementing a web-based point prevalence survey in 20 European countries using standardised definitions for site of infection, indication and quality indicators, such as whether the indication for prescription is documented in the case notes.3 As Australian studies of this type have not been published, we undertook a pilot study to assess whether this point prevalence tool is feasible and useful in an Australian setting.

All surgical inpatients (excluding intensive care patients) in Sydney’s Royal North Shore Hospital (a 541-bed tertiary referral hospital) at 8 am on a single day in December 2009 were included. Current prescriptions for antimicrobials were captured from the medication prescription charts, and data on duration of therapy, dose and route of administration were collected for that point in time to give a “snapshot” of prescribing on that day. We reviewed patients’ medical records to establish site of infection, indication for treatment, and whether the reason for the antimicrobial was documented. ESAC codes for site of infection and indication were used.

Of 178 patients, 95 (53%) had been prescribed 140 antimicrobials (ESAC mean, 30% of patients; range, 19%–59%).3 Cephazolin was the most commonly prescribed antimicrobial (32/140; 23%), and 115 antimicrobials (82%) were administered intravenously. Intra-abdominal sepsis (31/140; 22%) and cellulitis or wound infection (21/140; 15%) were the most common anatomical sites requiring treatment. Of the 140 prescriptions, 48 (34%) were for community-acquired infections, 29 (21%) were for postoperative infections, and 35 (25%) were for surgical prophylaxis. Of the 35 prescriptions for surgical prophylaxis, 14 (40%) were administered for more than 1 day (ESAC, 57%).3 The reason for initiation of the antimicrobial was documented in the patient’s medical notes for 95 of 140 prescriptions (68%) (ESAC, 64%).3

Use of the ESAC methodology allowed us to benchmark our results against published international reports. However, it gave no information on the appropriateness of the prescriptions or whether they adhered to antimicrobial guidelines. The ESAC point prevalence tool is easily applicable to the Australian health care system and provides useful information on antimicrobial consumption and quality indicators at an institutional level. Addition of questions regarding appropriateness of prescribing could be incorporated to give further relevant information.4 Use of the same methodology in other Australian centres would enable comparison across institutions and, potentially, national and international collaboration.