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

Ho, Pak‐Leung; Liu, Chunjiao; Tong, Man-Ki; Fan, Pui-Man; Tse, Cindy Wing-Sze; Wu, Alan Ka-Lun; Cheng, Vincent Chi-Chung; Chow, Kam-Pui

doi:10.1016/j.jgar.2019.08.021

Cited by 9 publications

(11 citation statements)

References 23 publications

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“…In previous studies, the frequencies of ST27 among S. lugdunensis collections were variable, ranging from < 1 to 25% (Yeh et al, 2016;Dahyot et al, 2018;Noguchi et al, 2018). In our locality, this and our previous studies have demonstrated the widespread occurrence of the ST27/SCCmecV lineage in different patient populations (Ho et al, 2015(Ho et al, , 2020. Further studies are required to investigate the international occurrence the ST27/SCCmecV lineage and the prevalence of false-susceptibility to oxacillin from heteroresistance in S. lugdunensis.…”

Section: Cefoxitin-s 238supporting

confidence: 47%

“…The CLSI recommended using a 1-µL loop for spreading a bacterial suspension of 0.5 McFarland turbidity onto oxacillin agar salt agar as an option for detection of mecA-mediated resistance in S. aureus (CLSI, 2020). This and our previous work showed that the use of a higher inoculum (5-µL loop) is essential for reliable detection of the cefoxitin-DD susceptible/mecApositive S. lugdunensis isolates (Ho et al, 2020). In this study, sodium chloride was added to the test medium to enhance mecA expression and the 2% concentration follows that recommended for oxacillin MIC determination using the agar dilution method (Huang et al, 1993).…”

Section: Cefoxitin-s 238mentioning

confidence: 92%

“…A multiplex PCR was used to detect the mecA and mecC genes in all the isolates (Ho et al, 2020). Multilocus sequence typing and SCCmec types were determined by next generation sequencing using an Illumina NovaSeq Platform at an output of approximately 1 Gb per isolate, as previously reported (Ho et al, 2016;Liu et al, 2019).…”

Section: Molecular Studiesmentioning

confidence: 99%

“…Although the Clinical and Laboratory Standards Institute (CLSI) currently recommends the same set of test methods and breakpoints for S. aureus and S. lugdunensis, the reliability of the recommendations has not been validated using a large collection of mecA-positive S. lugdunensis (CLSI, 2020). Recently, we showed that oxacillin resistance in some mecApositive S. lugdunensis isolates cannot be reliably detected by the current disc (cefoxitin) and MIC (cefoxitin and oxacillin) breakpoints, and that improved detection can be achieved using a new oxacillin-salt agar (Muller-Hinton [MH] supplemented with 2 µg/ml oxacillin and 2% sodium chloride) (Ho et al, 2020). In the current work, we assessed the diagnostic performance of the new oxacillin-salt agar for detection of oxacillin resistance in consecutive, clinical S. lugdunensis isolates.…”

Section: Introductionmentioning

confidence: 99%

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Improved Detection of mecA-Mediated β-Lactam Resistance in Staphylococcus lugdunensis Using a New Oxacillin Salt Agar Screen

Law

Liu

et al. 2021

Front. Microbiol.

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Oxacillin resistance mediated by mecA in Staphylococcus lugdunensis is emerging in some geographic areas. We evaluated cefoxitin disk diffusion (DD) and a new oxacillin agar (supplemented with 2 μg/ml oxacillin and 2% sodium chloride) screen for the detection of mecA-mediated resistance in S. lugdunensis. A total of 300 consecutive, non-duplicated clinical S. lugdunensis isolates from diverse sources in Hong Kong in 2019 were tested. The categorical agreement and errors obtained between cefoxitin DD test, oxacillin agar screen and mecA PCR were analyzed. Isolates with discordant results were further tested by MIC, penicillin binding protein 2a (PBP2a) assays, population analysis and molecular typing. PCR showed that 62 isolates were mecA-positive and 238 isolates were mecA-negative. For cefoxitin DD results interpreted using S. aureus/S. lugdunensis breakpoints, the categorical agreement (CA) for two brands of Muller-Hinton agars, MH-II (Becton Dickinson) and MH-E (bioMérieux) were both 96.0%; MEs were both 0%; and VMEs were 19.4 and 12.9%, respectively. The new oxacillin agar reliably differentiated mecA-positive and mecA-negative isolates (100% CA) without any ME or VME results. The 8 isolates with false susceptibility in the cefoxitin DD testing had cefoxitin and oxacillin MICs in the susceptible range. The isolates showed heterogeneous oxacillin resistance with resistant subpopulations at low frequencies. All had positive PBP2a results and were typed as sequence type 27/SCCmec V. The findings highlight the inability of cefoxitin DD and MIC tests for reliable detection of some mecA-positive S. lugdunensis isolates.

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Section: Cefoxitin-s 238supporting

confidence: 47%

Section: Cefoxitin-s 238mentioning

confidence: 92%

Section: Molecular Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Improved Detection of mecA-Mediated β-Lactam Resistance in Staphylococcus lugdunensis Using a New Oxacillin Salt Agar Screen

Law

Liu

et al. 2021

Front. Microbiol.

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“…18 Detection of the mecA gene All S. aureus isolates that were resistant to cefoxitin 30 μg and positive on ORSAB examination were then subjected to a PCR test to detect the presence of the mecA gene. 19 The DNA extraction process was carried out according to the QIAamp DNA Mini Kit protocol (51304 & 51306), where previously the isolates were purified on MSA (HiMedia Pvt. Ltd, M118) and inoculated on MHA (Oxoid, CM0337).…”

Section: Oxacillin and Cefoxitin Disk Diffusion Methodsmentioning

confidence: 99%

Detection of mecA gene and methicillin-resistant Staphylococcus aureus (MRSA) isolated from milk and risk factors from farms in Probolinggo, Indonesia

et al. 2022

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Background: Staphylococcus aureus is commonly found in dairy cows and is a source of contamination in milk. S. aureus that are resistant to beta-lactam antibiotics are referred to as methicillin-resistant Staphylococcus aureus (MRSA). The spread of MRSA cannot be separated from sanitation management during milking; it can originate from milk collected from the udder or from the hands of farmers during the milking process. The purpose of this study was to examine the level of MRSA contamination in dairy cow's milk and farmer's hand swabs. Methods: A total of 109 samples of dairy cow’s milk and 41 samples of farmers’ hand swabs were collected at a dairy farm in Probolinggo, East Java, Indonesia. Samples were cultured and purified using mannitol salt agar (MSA). The profile of S. aureus resistance was established by disk diffusion test using a disk of beta-lactam antibiotics, namely oxacillin and cefoxitin. Results: The S. aureus isolates that were resistant to oxacillin and cefoxitin antibiotics were then tested for oxacillin resistance screening agar base (ORSAB) as a confirmation test for MRSA identity. S. aureus isolates suspected to be MRSA were then tested genotypically by polymerase chain reaction (PCR) method to detect the presence of the mecA gene. The results of the isolation and identification found 80 isolates (53.33%) of S. aureus. The results of the resistance test found that 42 isolates (15%) of S. aureus were resistant to oxacillin and 10 isolates (12.5%) were resistant to cefoxitin. The ORSAB test found as many as 20 isolates (47.62%) were positive for MRSA. In PCR testing to detect the presence of the mecA gene, three isolates (30%) were positive for the mecA gene. Conclusions: This study shows that several S. aureus isolates were MRSA and had the gene encoding mecA in dairy farms.

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Virulence factor genes and antimicrobial susceptibility of Staphylococcus lugdunensis strains

Budzyńska,

Wiktorczyk-Kapischke,

Grudlewska-Buda

et al. 2023

Journal of Infection

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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

Cited by 9 publications

References 23 publications

Improved Detection of mecA-Mediated β-Lactam Resistance in Staphylococcus lugdunensis Using a New Oxacillin Salt Agar Screen

Improved Detection of mecA-Mediated β-Lactam Resistance in Staphylococcus lugdunensis Using a New Oxacillin Salt Agar Screen

Detection of mecA gene and methicillin-resistant Staphylococcus aureus (MRSA) isolated from milk and risk factors from farms in Probolinggo, Indonesia

Virulence factor genes and antimicrobial susceptibility of Staphylococcus lugdunensis strains

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