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The microbiology lab and AMS

In this article, we discuss the role of the microbiology lab in an AMS programme.

It is important to understand how your microbiology laboratory can support AMS. This section will address what role the microbiology laboratory plays in antimicrobial stewardship (AMS).

A shield in a bubble under attack by viruses

The approach to AMS, and particularly how empiric treatment is guided and surveillance of resistance, will be very dependent on microbiological laboratory capacity and capability. Microbiology capacity and capability in many LMICs is lacking or scarce. National AMS action plans clearly outline how microbiology services can support AMS as shown in the diagram below.

Action plans for microbiology laboratories to promote AMS – 4 factors: sample testing, using antibiograms, communicating results, timely sampling.

An excellent 2017 article reviewed the multiple avenues by which clinical microbiology laboratories can contribute to AMS efforts. The article described the six Ds of AMS and the associated key roles of microbiology laboratories. The key points are summarised below.

Six D’s of AMS and associated key roles of microbiology laboratories: diagnose, debridement/drainage, drug, dose, duration, de-escalation.

The study also went on to outline a number of antimicrobial stewardship activities that can be done by the microbiology laboratory. The diagram below shows the essential activities.

Nine essential directives for the microbiology lab: timely results, active participation, local education, prompt reporting, optimized communication, providing CASR, guidance for sample taking, using a cascade, and collaboration with infectious disease clinicians.

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This infographic is also available as a screen-reader compatible PDF.

Furthermore, a 2018 article reviewed the WHO’s List of essential laboratory diagnostics and highlighted the importance of effective diagnostics in supporting clinicians in delivering AMS. The box below outlines the basic requirements for healthcare facilities to support AMS, detailed in the WHO 2018 list of ‘in vitro’ diagnostics (IVDs).

Healthcare facilities with clinical laboratories: general IVDs: urine dipstick and microscopy, culture of specimens, blood culture, and AST.

Including culture and AST in the WHO list is a significant step forward. However, many resource-limited hospitals in LMICs cannot routinely and accurately perform culture and AST. Therefore, in some facilities, diagnosis of serious bacterial infections often relies on clinical judgement alone and antibiotics are prescribed empirically without culture and AST.

Clinicians are far more likely to take appropriate steps in antimicrobial administration if they know exactly what they are treating (which pathogen) and which antibiotics will work. Microbiology laboratories need to be equipped with the necessary resources to allow scientifically supported diagnoses and treatment options to be established.

The advantages of culturing and antimicrobial susceptibility testing are summarised in the figure below.

Advantages of culturing and AST: pathogen ID, selecting antimicrobials, minimizing antimicrobial use, identifying resistance, preventing antimicrobial overuse, better outcomes

It is common practice for clinicians in all settings to adopt an empiric syndromic approach to treating a range of common infections.

Diagnostic testing is crucial to appropriate management at both community and hospital levels. At the community level, most of the overprescribing happens due to antibiotic prescribing only based on signs and symptoms.

If no microbiology samples are taken when commencing empiric antimicrobial treatment, then no microbiological diagnosis (pathogen identification and AST) can be established. This leads to inappropriate (incorrect choice, protracted duration or too broad spectrum) treatment, which may be ineffective, and will promote AMR and other related adverse events.

Close collaboration and communication between the laboratory and prescribing clinicians is essential for good AMS practice to ensure that every patient receives the most appropriate treatment.

Now over to you! Do you have a laboratory that supports AMS practice in your hospital? Think of some ways in which your lab supports AMS practice. Discuss in the comments below.

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How to set up an Antimicrobial Stewardship Programme

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