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Article: Evaluation of disc diffusion tests and agar screening for predicting mecA-mediated oxacillin resistance in Staphylococcus lugdunensis revealed a cefoxitin-susceptible, mecA-positive S. lugdunensis clonal complex 27 clone

TitleEvaluation of disc diffusion tests and agar screening for predicting mecA-mediated oxacillin resistance in Staphylococcus lugdunensis revealed a cefoxitin-susceptible, mecA-positive S. lugdunensis clonal complex 27 clone
Authors
KeywordsOxacillin resistance
SCCmec
Staphylococci
Issue Date2020
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/issn/22137165
Citation
Journal of Global Antimicrobial Resistance, 2020, v. 20, p. 260-265 How to Cite?
AbstractObjectives: This study evaluated disc diffusion tests and agar screening for detecting mecA-mediated oxacillin resistance in Staphylococcus lugdunensis (S. lugdunensis). Methods: Staphylococcus lugdunensis isolates (n = 179) from diverse sources in Hong Kong during 1998–2018 were investigated by disc diffusion tests (cefoxitin and oxacillin) and inoculation onto oxacillin (1 μg/mL and 2 μg/mL) and chromID methicillin-resistant Staphylococcus aureus (MRSA) agars. The results were compared with mecA PCR as the reference. Isolates with discordant results were further tested by MIC and penicillin-binding protein 2a (PBP2a) assays. Results: Cefoxitin and oxacillin zone diameters were not distributed in ways that allowed reliable division of the mecA-positive (n = 52) and mecA-negative (n = 127) isolates. On applying the 2019 Clinical Laboratory Standards Institute (CLSI) M100 breakpoints for cefoxitin disc results, there was 88% categorical agreement (CA) and 40% very major error (VME). Screening using 2 μg/mL oxacillin agar reliably differentiated mecA-positive and mecA-negative isolates (100% CA) without any major error (ME) or VME results. The performance of screening using 1 μg/mL oxacillin agar or ChromID MRSA agar was variable (74–89% CA, 0–38% ME and 0–37% VME). The mecA-positive isolates (n = 21) that could not be detected by the cefoxitin disc test were further characterised. The cefoxitin MIC for all 21 isolates was ≤4 μg/mL. Twenty isolates had an oxacillin MIC of 1–2 μg/mL and one had an oxacillin MIC of 4 μg/mL. All had positive PBP2a results and were typed as clonal cluster 27/SCCmec V. Conclusions: These findings highlight the need to evaluate phenotypic methods using mecA-positive S. lugdunensis with different oxacillin resistance phenotypes.
Persistent Identifierhttp://hdl.handle.net/10722/285097
ISSN
2023 Impact Factor: 3.7
2023 SCImago Journal Rankings: 0.880
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorHo, PL-
dc.contributor.authorLIU, MCJ-
dc.contributor.authorTONG, MK-
dc.contributor.authorFan, PM-
dc.contributor.authorTse, CWS-
dc.contributor.authorWu, AKL-
dc.contributor.authorCheng, VCC-
dc.contributor.authorChow, KH-
dc.date.accessioned2020-08-07T09:06:42Z-
dc.date.available2020-08-07T09:06:42Z-
dc.date.issued2020-
dc.identifier.citationJournal of Global Antimicrobial Resistance, 2020, v. 20, p. 260-265-
dc.identifier.issn2213-7165-
dc.identifier.urihttp://hdl.handle.net/10722/285097-
dc.description.abstractObjectives: This study evaluated disc diffusion tests and agar screening for detecting mecA-mediated oxacillin resistance in Staphylococcus lugdunensis (S. lugdunensis). Methods: Staphylococcus lugdunensis isolates (n = 179) from diverse sources in Hong Kong during 1998–2018 were investigated by disc diffusion tests (cefoxitin and oxacillin) and inoculation onto oxacillin (1 μg/mL and 2 μg/mL) and chromID methicillin-resistant Staphylococcus aureus (MRSA) agars. The results were compared with mecA PCR as the reference. Isolates with discordant results were further tested by MIC and penicillin-binding protein 2a (PBP2a) assays. Results: Cefoxitin and oxacillin zone diameters were not distributed in ways that allowed reliable division of the mecA-positive (n = 52) and mecA-negative (n = 127) isolates. On applying the 2019 Clinical Laboratory Standards Institute (CLSI) M100 breakpoints for cefoxitin disc results, there was 88% categorical agreement (CA) and 40% very major error (VME). Screening using 2 μg/mL oxacillin agar reliably differentiated mecA-positive and mecA-negative isolates (100% CA) without any major error (ME) or VME results. The performance of screening using 1 μg/mL oxacillin agar or ChromID MRSA agar was variable (74–89% CA, 0–38% ME and 0–37% VME). The mecA-positive isolates (n = 21) that could not be detected by the cefoxitin disc test were further characterised. The cefoxitin MIC for all 21 isolates was ≤4 μg/mL. Twenty isolates had an oxacillin MIC of 1–2 μg/mL and one had an oxacillin MIC of 4 μg/mL. All had positive PBP2a results and were typed as clonal cluster 27/SCCmec V. Conclusions: These findings highlight the need to evaluate phenotypic methods using mecA-positive S. lugdunensis with different oxacillin resistance phenotypes.-
dc.languageeng-
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/issn/22137165-
dc.relation.ispartofJournal of Global Antimicrobial Resistance-
dc.rightsThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.-
dc.subjectOxacillin resistance-
dc.subjectSCCmec-
dc.subjectStaphylococci-
dc.titleEvaluation of disc diffusion tests and agar screening for predicting mecA-mediated oxacillin resistance in Staphylococcus lugdunensis revealed a cefoxitin-susceptible, mecA-positive S. lugdunensis clonal complex 27 clone-
dc.typeArticle-
dc.identifier.emailHo, PL: plho@hku.hk-
dc.identifier.emailFan, PM: fpmjoyce@hku.hk-
dc.identifier.emailWu, AKL: alanklwu@hkucc.hku.hk-
dc.identifier.emailCheng, VCC: vcccheng@hkucc.hku.hk-
dc.identifier.emailChow, KH: khchowb@hku.hk-
dc.identifier.authorityHo, PL=rp00406-
dc.identifier.authorityChow, KH=rp00370-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1016/j.jgar.2019.08.021-
dc.identifier.pmid31493529-
dc.identifier.scopuseid_2-s2.0-85079197603-
dc.identifier.hkuros312547-
dc.identifier.volume20-
dc.identifier.spage260-
dc.identifier.epage265-
dc.identifier.isiWOS:000522221800050-
dc.publisher.placeNetherlands-
dc.identifier.issnl2213-7165-

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