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FIGURE 1

The ‘ optimal ’ equation for appropriate antimicrobial prescribing

Appropriate sampling

Rapid action by clinician to prescribe / adjust antimicrobial therapy early pathogen identification and streamlining of the treatment plan once culture and susceptibility data are available may minimise antibiotic resistance and improve the utility of these drugs . ³ The impact of antimicrobial stewardship programmes ( ASPs ) on patient , prescribing , and microbial outcomes was examined in a systematic review of studies conducted on hospital inpatients . As noted by the authors , although the overall quality of the evidence was low simply because the studies were not powered to demonstrate the impact on patient outcomes , the results suggest that ASPs did reduce antimicrobial prescribing or improve appropriate use . ⁴ Two other systematic reviews revealed a significant reduction of infections with antibiotic-resistant bacteria ⁵ and cost savings with improvement of specific patient outcomes in the hospital setting . ⁶

While in some countries , such as the US and the UK , most hospitals will have ASPs in place , it is essential that the teams are multidisciplinary and include laboratory staff such as clinical microbiologists . ⁷ Expert laboratory personnel have been relegated for too long to the role of mere providers of support services . Through their integration into ASPs , clinical microbiologists are becoming increasingly recognised as experts in their field and are thus in an ideal position to advise their medical colleagues on which diagnostic tests to request and how the results should be interpreted . Figure 1 shows the optimal equation for appropriate antimicrobial prescribing .

Diagnostic stewardship According to the Global Antimicrobial Resistance Surveillance System ( GLASS ), ⁸ diagnostic stewardship is defined as : “ Coordinated guidance and interventions to improve appropriate use of microbiological diagnostics to guide therapeutic decisions . It should promote appropriate , timely diagnostic testing , including specimen collection , and pathogen identification , and accurate , timely reporting of results to guide patient treatment .” As part of the overarching AMS approach , diagnostic stewardship is designed to ensure that the correct tests are performed for a given clinical setting and directed towards the appropriate patients . Moreover , the diagnostic process is not simply about the choice of antimicrobial , and the goal of diagnostic stewardship consists in selecting the right test for the right patient ( Figure 2 ). In achieving this aim , it is also expected that the tests selected will generate accurate and clinically relevant results to optimise clinical care while conserving healthcare resources . ⁹

When faced with diagnostic stewardship for infectious diseases , Messacar et al ⁹ defined three key questions that should be considered prior to the use of rapid diagnostic testing : 1 . Is the test appropriate in the clinical setting ? 2 . Will the clinical care of the patient be affected by the test result ? 3 . Will the result be available in time to optimally affect care ?

Using acute respiratory tract infections as an example , the appropriate use of diagnostic tests can lead to improvements in patient management . This is especially relevant given the fact that many infections are of viral , rather than bacterial , >