Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting
Date
2021-02-15
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
BMC (part of Springer Nature)
Abstract
Background: Positive blood cultures showing Gram positive cocci in clusters signifies either Staphylococcus aureus or the
less-virulent coagulase-negative staphylococci. Rapid identification and methicillin susceptibility determination with the Xpert
MRSA/SA BC assay can improve management of S. aureus bloodstream infection and reduce inappropriate antibiotic use.
Methods: We prospectively evaluated the Xpert MRSA/SA BC assay in comparison with culture, on samples referred to our
laboratory in the Western Cape, South Africa. We interviewed attending clinicians upon culture result availability, to assess
antibiotic choices and estimate potential impact of the assay.
Results: Of the 231 samples included, there was 100% concordance between the Xpert MRSA/SA BC assay and culture
(methicillin-resistant S. aureus 15/15, methicillin-susceptible S. aureus 42/42, coagulase-negative staphylococci 170/170). Time to
final result could be reduced by approximately 30 h with the assay. Of the 178 patients with adequate antibiotic history,
optimisation of antistaphylococcal therapy could have occurred more than 1 day sooner in 68.9% with S. aureus bloodstream
infection (31/45, 95% CI 53.2–81.4%). Six of the 11 patients with methicillin-resistant S. aureus bloodstream infection (54.5%)
could have received anti-MRSA cover sooner. Fifty-four days of antibiotic therapy could have been spared, equating to 0.3 days
(95% CI, 0.2–0.4) saved per patient, driven by broad-spectrum beta-lactams (32 days, in 18.0% of the cohort).
Conclusion: This assay has potential as an antimicrobial stewardship tool; costing and impact on clinical outcome in patients
with S. aureus bloodstream infection should be assessed.
Description
CITATION: Reddy, K. & Whitelaw, A. 2021. Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting. BMC Infectious Diseases, 21:177, doi:10.1186/s12879-021-05857-7.
The original publication is available at https://bmcinfectdis.biomedcentral.com
The original publication is available at https://bmcinfectdis.biomedcentral.com
Keywords
Staphylococcus aureus, Staphylococcal infections, Antimicrobials, Xpert MRSA/SA BC
Citation
Reddy, K. & Whitelaw, A. 2021. Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting. BMC Infectious Diseases, 21:177, doi:10.1186/s12879-021-05857-7