Aura 2016: first Australian report on antimicrobial use and resistance in human health

5.3 Commentary

Australia has high rates of AU in both hospitals and the community, but our rates of antimicrobial resistance (at least for gram-negative organisms) are low compared with European countries and the United States. For hospital use, Australia can rank well or poorly compared with other countries, depending on which measure is used. The reasons for these differences are unclear at present. Improving coverage of NAUSP to include more hospitals will help to provide a more accurate picture of AU and antimicrobial resistance in Australian hospitals.

Restrictions on fluoroquinolone use in Australia mean that the use of this class of antimicrobials is lower than in many other countries. These restrictions may also contribute to the low rates of resistance to this class seen in Australia compared with other countries.

Chapter 6 Emerging issues

Key messages

Data indicates that carbapenems – the last-line antimicrobials for infections with multidrug-resistant Enterobacteriaceae, Escherichia coli and Klebsiella species – are being used suboptimally in Australian hospitals. Continued monitoring and revision of prescribing practices are needed to reduce inappropriate use.

Carbapenemase-producing organisms are present in Australia at low levels, but are widely disseminated across the country in humans, animals and the environment. These organisms have high epidemic potential, and healthcare services and microbiology laboratories need to be vigilant in detecting and responding to them. The Australian Commission on Safety and Quality in Health Care is developing a national alert system to provide assistance for the early identification and spread of these types of organisms.

Surgical prophylaxis is a key area of inappropriate antimicrobial use. The Surgical National Antimicrobial Prescribing Survey (sNAPS) was piloted in 2015, and identified high levels of inappropriate use in both perioperative and postoperative management. Further work is under way to address these issues.

This chapter explores some key issues for antimicrobial use and antimicrobial resistance that highlight the importance of surveillance and the action that may be required. The organisms and antimicrobials identified in this section are regarded as currently posing a risk to human health, or likely to pose a risk in the near future.

6.1 Carbapenem use in Australian hospitals

Carbapenems are the last-line treatment for serious infections caused by multidrug-resistant Escherichia coli, Klebsiella species and other Enterobacteriaceae. It is important that carbapenem use in hospitals is minimised and reserved for treatment of serious gram-negative infections in cases where other antimicrobials are not effective or appropriate.

Hospitals that contribute data to the National Antimicrobial Utilisation Surveillance Program (NAUSP) show wide variation in the use of carbapenems, indicating the possibility of suboptimal use in some settings. Individual hospital carbapenem use, expressed as defined daily doses per 1000 occupied-bed days, is presented in Figures 6.1–6.3. Among the principal referral hospitals, there is a six-fold difference between the highest and lowest carbapenem users (excluding the lowest outlier). Similar variations are seen in the other hospital peer groups, although their overall usage rates are much lower.

Figure 6.1 Carbapenem use in principal referral hospitals, 2014–15

DDD/1000 OBD = defined daily doses per 1000 occupied-bed days

Source: National Antimicrobial Utilisation Surveillance Program

Figure 6.2 Carbapenem use in large public acute hospitals, 2014–15

DDD/1000 OBD = defined daily doses per 1000 occupied-bed days

Source: National Antimicrobial Utilisation Surveillance Program

Figure 6.3 Carbapenem use in medium public acute hospitals, 2014–15

DDD/1000 OBD = defined daily doses per 1000 occupied-bed days

Source: National Antimicrobial Utilisation Surveillance Program

If carbapenems are being used optimally – that is, to treat infections caused by organisms that produce extended-spectrum -lactamases (ESBLs) – there should be a positive relationship between carbapenem use and the rate of isolation of ESBL-producing strains. This was analysed in data from a subset of 23 hospitals that participated in NAUSP and the Australian Group on Antimicrobial Resistance in 2014. Figure 6.4 shows that there was no relationship between the amount of meropenem supplied and the rates of ESBL-producing strains isolated in these hospitals. This means there is probably suboptimal use in some hospitals.

Figure 6.4 Meropenem supplied versus extended-spectrum β-lactamase-producing strains isolated in hospitals, 2014

DDD/1000 OBD = defined daily doses per 1000 occupied-bed days; ESBL = extended-spectrum β-lactamase

Source: National Antimicrobial Utilisation Surveillance Program

Current guidelines

The Australian Commission on Safety and Quality in Health Care (the Commission) has published an information sheet for clinicians on carbapenemase-producing Enterobacteriaceae (CPE).⁶³ The information sheet outlines measures that should be taken to minimise overall antimicrobial use (AU) and optimise use of key gram-negative antimicrobials, such as carbapenems. The measures include:

ensuring that AU is consistent with Therapeutic guidelines: antibiotic,²⁰ taking into consideration local susceptibility information

monitoring the use of antimicrobials and aiming to reduce overall use of cephalosporins, carbapenems and quinolone classes in intensive-care units (ICUs) and non-ICU settings

avoiding the empirical use of broad-spectrum -lactam antimicrobials (including third- and fourth-generation cephalosporins and carbapenems) for respiratory tract infections, surgical prophylaxis and urinary tract infections.

Potential actions

Hospitals with high carbapenem use should review their use in line with current guidelines. Participation in the National Antimicrobial Prescribing Survey (NAPS) can help hospitals to identify areas for improvement and design strategies to reduce inappropriate use. The more hospitals that participate in NAPS, the more we will understand about prescribing practices in individual hospitals and throughout Australia. It may be informative to establish a national target or indicator for appropriate carbapenem use in Australia, and use NAPS to monitor this every year.