{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T00:09:51Z","timestamp":1792714191162,"version":"4.5.0"},"reference-count":29,"publisher":"Oxford University Press (OUP)","issue":"6","license":[{"start":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T00:00:00Z","timestamp":1613952000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,5,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Objectives<\/jats:title>\n                  <jats:p>Correct determination of penicillin susceptibility is pivotal for using penicillin in the treatment of Staphylococcus aureus infections. This study examines the performance of MIC determination, disc diffusion and a range of confirmatory tests for detection of penicillin susceptibility in S. aureus.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>A total of 286 consecutive penicillin-susceptible S. aureus blood culture isolates as well as a challenge set of 62 MSSA isolates were investigated for the presence of the blaZ gene by PCR and subjected to penicillin-susceptibility testing using broth microdilution MIC determination, disc diffusion including reading of the zone edge, two nitrocefin tests and the cloverleaf test.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>Using PCR-based detection of blaZ as the gold standard, both broth microdilution MIC testing and disc diffusion testing resulted in a relatively low accuracy (82%\u201393%) with a sensitivity ranging from 49%\u201393%. Among the confirmatory tests, the cloverleaf test performed with 100% accuracy, while zone edge interpretation and nitrocefin-based tests increased the sensitivity of \u03b2-lactamase detection to 96%\u201398% and 82%\u201396% when using MIC determination or disc diffusion as primary test, respectively.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>This investigation showed that reliable and accurate detection of \u03b2-lactamase production in S. aureus can be obtained by MIC determination or penicillin disc diffusion followed by interpretation of the zone edge as a confirmatory test for apparently penicillin-susceptible isolates. The more cumbersome cloverleaf test can also be used. Nitrocefin-based tests should not be used as the only test for confirmation of a presumptive \u03b2-lactamase-negative isolate.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/jac\/dkab032","type":"journal-article","created":{"date-parts":[[2021,1,26]],"date-time":"2021-01-26T20:10:52Z","timestamp":1611691852000},"page":"1487-1494","source":"Crossref","is-referenced-by-count":23,"title":["Evaluation of methods for detection of \u03b2-lactamase production in MSSA"],"prefix":"10.1093","volume":"76","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6079-5381","authenticated-orcid":false,"given":"Robert","family":"Skov","sequence":"first","affiliation":[{"name":"Division of Infectious Disease Preparedness, Statens Serum Institut, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David R","family":"Lonsway","sequence":"additional","affiliation":[{"name":"Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jesper","family":"Larsen","sequence":"additional","affiliation":[{"name":"Department of Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anders Rhod","family":"Larsen","sequence":"additional","affiliation":[{"name":"Department of Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jurgita","family":"Samulionien\u00e9","sequence":"additional","affiliation":[{"name":"Department of Clinical Microbiology, Aalborg University Hospital, Alborg, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brandi M","family":"Limbago","sequence":"additional","affiliation":[{"name":"Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, 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