How the lab can better support optimal prescribing and it’s role in surveillance

The clinical microbiology laboratory is important in antimicrobial stewardship.

The clinical microbiology laboratory acts as a link between antibiotic stewardship and infection control.

In a lab, the staff carry out surveillance and provide data on multi-drug resistant organisms for infection control purposes. In step 2.2 Dr Oshun highlighted the need for samples and laboratory results to enable rational antibiotic prescribing.

The laboratory should have antibiotic stewardship in mind when choosing or designing their information system.

Effective communication and collaboration between the clinical microbiology laboratory, prescribers and antibiotic stewardship team is important. Procedures should be in place, by the laboratory, to ensure effective communication, and these procedures should be regularly reviewed and updated.

The laboratory provides information on infections and their causative agents. It provides pathogen detection and antibiotics susceptibility results for individual patients which can be used for targeted therapy.

In spite of this, the laboratory is under utilised and sometimes, results from the lab are disregarded because they are not trusted.

To improve antimicrobial prescribing, it is important that a clinical microbiologist is part of the antibiotic stewardship programme. This will enhance communication between the lab and prescribers These are the roles of a clinical microbiologist and the lab:

• The clinical microbiologist will ensure good laboratory practice; and that good quality specimens are collected from patients by making policies and guidelines for specimen collection and transportation available to the clinicians.

• The lab should be able to assess specimen quality and reject inappropriate specimens providing clearly stated reasons for the rejection communicated to the clinician(s) that requested the tests.

• The clinical microbiologist should ensure that clinicians are aware of available tests and how the tests can enhance their prescribing practices and patient outcome. He/she should communicate with prescribers directly even when laboratory information systems are available and input results into the patient management system whenever necessary (especially for critical results and high risk patient groups such as those in intensive care unit). They should provide comments on lab reports to help guide appropriate antimicrobial therapy and ensure direct notification of laboratory reports to clinicians. He/she should also provide guidance for interpretation of the report.

• The clinical microbiologist should provide education to prescribers about appropriate antimicrobial use. Before new tests, such as rapid diagnostic tests are introduced, they should inform the clinicians and educate them on the technology, indications, advantages and limitations; turnaround time, presentation of the report and any other information as deemed necessary.

• The clinical microbiologist should ensure that antibiograms are reported and updated periodically to guide empiric therapy and local antibiotic guidelines.

• The clinical microbiologist should be actively involved in the development and review of the policies and guidelines.

• In conjunction with antimicrobial stewardship committee, they should decide which agents to report routinely and those to be reported selectively after antimicrobial susceptibility test (AST)[cascade reporting, which involves reporting the susceptibilities of broad-spectrum agents only when the organism is resistant to more narrow-spectrum agents]. Also, the laboratory should do antibiotic susceptibility testing only on clinically relevant specimen and that analysis of AST results are according to expert rules. For organisms that show resistance, it is helpful to determine their resistance mechanisms.

It is essential for the laboratory to employ the best practice diagnostic tests for a range of pathogens to deliver accurate and timely results so as to enable clinicians to target antimicrobial therapy or cease unnecessary antimicrobials. Use of biomarkers such as procalcitonin or C- reactive protein in addition to pathogen diagnostic tests plus AST (antibiotic susceptibility testing) are to be used for directed therapy. Rapid diagnostic tests such as meningitis panel, Rapid Strep A (RST), multiplex PCR (polymerase chain reaction) and MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization time of flight mass spectrometry) should be employed where possible.

Questions

• Does your microbiology lab reject inadequate or inappropriate samples? If so, do they accompany it with sample rejection form or written reasons for rejection?

• What rapid diagnostic tests do you use in your facility and how does it help in antibiotics prescribing?

• In your facility, are samples collected for microbiology investigations before commencement of antibiotics or when it seems the prescribed antibiotics have failed? Are there written guidelines for specimen collection from patients.

• How can you ensure that good quality specimens are collected from patients in your facility?