Evaluation of New Vitek 2 Card and Disk Diffusion Method for Determining Susceptibility of
            <i>Staphylococcus aureus</i>
            to Oxacillin

Roisin, Sandrine; Nonhoff, Claire; Denis, Olivier; Struelens, Marc

doi:10.1128/jcm.00291-08

Cited by 35 publications

(13 citation statements)

References 19 publications

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“…Their study and ours were performed with strain collection from different time periods, and the prevalence of staphylococcal methicillin heteroresistance may have changed in France between 2006 and 2014 (Join-Lambert et al study [17] and our collection, respectively). We hypothesize that the use of a higher inoculum may have attenuated the difference in performance between cefoxitin and moxalactam for detecting heteroresistant isolates as previously noted by Roisin et al (18). Overall, the results of this study suggest that cefoxitin should remain the preferred marker for detecting methicillin resistance in current disk diffusion testing protocols.…”

Section: The Distribution Of Cefoxitin and Moxalactam Izds For S Aursupporting

confidence: 56%

“…This recommendation was based on the observation that disk diffusion with both cefoxitin and moxalactam was more accurate than cefoxitin alone in differentiating heteroresistant S. aureus and CoNS isolates from methicillin-susceptible isolates at low inoculum levels (colony suspension at 10 6 CFU/ml) (15)(16)(17). However, scarce discrepant data, available only at higher inoculum levels (colony suspension at 10 8 CFU/ml), have led to questions regarding a potential interest in including moxalactam in the EUCAST and CLSI recommendations (17,18).…”

mentioning

confidence: 99%

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Disk Diffusion Testing for Detection of Methicillin-Resistant Staphylococci: Does Moxalactam Improve upon Cefoxitin?

Hodille

Dumitrescu

et al. 2016

J Clin Microbiol

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dDisk diffusion testing is widely used to detect methicillin resistance in staphylococci, and cefoxitin is currently considered the best marker for mecA-mediated methicillin resistance. In low-inoculum diffusion testing (colony suspension at 10 6 CFU/ml), the addition of moxalactam in combination with cefoxitin has been reported to improve on cefoxitin alone for the detection of methicillin-heteroresistant staphylococci. However, moxalactam is absent from EUCAST and CLSI guidelines, which use highinoculum diffusion testing (colony suspension at 10 8 CFU/ml), calling into question the potential interest of including moxalactam in their recommendations. The inhibition zone diameters of cefoxitin and moxalactam, alone and in combination, were evaluated for concordance with mecA and mecC positivity in a large collection of clinical Staphylococcus isolates (611 Staphylococcus aureus, Staphylococcus lugdunensis, and Staphylococcus saprophyticus isolates and 307 coagulase-negative staphylococci other than S. lugdunensis and S. saprophyticus isolates, of which 22% and 53% were mecA-positive, respectively) and in 25 mecC-positive S. aureus isolates using high-inoculum diffusion testing. Receiver operating characteristic, sensitivity, and specificity analyses indicated that the detection of mecA-and mecC-positive and negative isolates did not improve with moxalactam, either alone or in combination with cefoxitin, compared to cefoxitin alone. These findings were similar in both the S. aureus/S. lugdunensis/S. saprophyticus group and in the coagulase-negative staphylococci group. Our results do not support the use of moxalactam as an additional marker of methicillin resistance when testing with high-inoculum disk diffusion.

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Section: The Distribution Of Cefoxitin and Moxalactam Izds For S Aursupporting

confidence: 56%

mentioning

confidence: 99%

Disk Diffusion Testing for Detection of Methicillin-Resistant Staphylococci: Does Moxalactam Improve upon Cefoxitin?

Hodille

Dumitrescu

et al. 2016

J Clin Microbiol

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“…Metisilin direncinin belirlenmesinde otomatize sistemler de kullanılmaktadır. Roisin ve arkadaşları 12 , SDD testinin duyarlılık ve özgüllüğünü tüm MRSA izolatlarında sırasıyla %98.7 ve %100, otomatize sistemin ise sırasıyla %97.5 ve %100 olarak rapor etmiştir. Başka bir çalışmada 5 duyarlılık ve özgüllük sırasıyla otomatize yöntemde %94 ve %100, SDD testinde ise her ikisi de %100 olarak bulunmuştur.…”

Section: Discussionunclassified

Comparison of Cefoxitin Disk Diffusion Test, Automated System and Chromogenic Medium for Detection of Methicillin Resistance in Staphylococcus aureus Isolates

Uzun¹,

Şener²,

Güngör³

et al. 2013

Mikrobiyol Bul

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The mecA gene is responsible for the development of methicillin resistance in staphylococci however accurate detection of methicillin resistance is not feasible evermore because of heterogenous expression of mecA gene. Although mecA gene determination by polymerase chain reaction (PCR) is considered as the gold standard method, molecular tests are not easily applied in all routine laboratories. Thus, for the rapid and accurate diagnosis of MRSA strains, easy and practical phenotypic tests are still required. This study was aimed to compare the performance of mecA gene analysis by gel bases multiplex PCR with dual primer (Seeplex, Seegene Inc, Korea), cefoxitin disc diffusion method (30 µg, Oxoid, UK), automated system (Phoenix 100, Becton Dickinson, USA) and chromogenic medium CHROMagar MRSA (CHROMagar Microbiology, Salubris, Turkey) for the detection of methicillin resistance in staphylococci. It was found that 60 of the 98 Staphylococcus aureus strains carried the mecA gene. Methicillin resistance was observed by cefoxitin disc diffusion test in 59 isolates, by automated system in 61 isolates, and by CHROMagar MRSA in 65 isolates. When mecA gene analysis was considered as the reference method, the sensitivity, specificity, positive and negative predictive values of the tests that were used for the detection of methicillin resistance were found as 98.3%, 100%, 100% and 97.4% for cefoxitin disc diffusion (CDD) method; 100%, 97.4%, 98.4% and 100% for automated system; 96.7%, 81.6%, 89.2% and 93.9% for chromogenic medium CHROMagar MRSA, respectively. The highest sensitivity and negative predictive values were obtained by the automated system, and the highest specificity and positive predictive values were obtained by the CDD test. Although the sensitivity of chromogenic medium was found to be similar with the CDD test at the end of 48 hours, the specificity of chromogenic medium was lower than the other tests at the end of each incubation period. Likewise, positive and negative predictive values of the chromogenic medium were determined low compared to other tests. In laboratories that cannot perform molecular analysis, the determination of methicillin resistance should be done by the CDD test which is known to be a better inducer of the mecA gene expression of staphylococci. Determination of minimum inhibitory concentration (MIC) with automated systems can be the second choice especially in laboratories with intensive work loads. As a result chromogenic media can be particularly used for screening in laboratories that have a heavy workload and insufficient personnel number. However, due to its low specificity and the possibility of false positive results, it was recommended that positive strains should be confirmed by other methods such as disc diffusion or microdilution.

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“…One such system is Vitek 2 (bioMérieux, Marcy l'Etoile, France), which has been successfully used for the detection and differentiation of mecA and mecC containing MRSA strains, based on differences in their resistance to cefoxitin and oxacillin [33]. These tests are not, however, suitable for fast MRSA confirmation as the time to final susceptibility reporting requires typically 6-12 h (Table 1) [34]. In addition, as MRSA strains are often heteroresistant to β-lactam antibiotics and only a small fraction of cells express the resistant phenotype under in vitro test conditions, some isolates may be missed by these tests.…”

Section: Non-nucleic Acid-based Detection Of Mrsamentioning

confidence: 99%

The Use of Molecular Methods for the Detection and Identification of Methicillin-Resistant Staphylococcus Aureus

Hirvonen¹

2014

Biomark. Med.

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Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen in many hospitals and long-term care facilities as well as in the community. To limit the spread of MRSA, early detection and proper treatment are essential. Because conventional culture as gold standard is time consuming, new techniques such as PCR-based and hybridization assays have emerged for the rapid detection of MRSA. This review will focus on the currently available molecular-based assays and on their utility and performance for detection of S. aureus, of its virulence factors and of the markers for acquired resistance.

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Evaluation of New Vitek 2 Card and Disk Diffusion Method for Determining Susceptibility of Staphylococcus aureus to Oxacillin

Cited by 35 publications

References 19 publications

Disk Diffusion Testing for Detection of Methicillin-Resistant Staphylococci: Does Moxalactam Improve upon Cefoxitin?

Disk Diffusion Testing for Detection of Methicillin-Resistant Staphylococci: Does Moxalactam Improve upon Cefoxitin?

Comparison of Cefoxitin Disk Diffusion Test, Automated System and Chromogenic Medium for Detection of Methicillin Resistance in Staphylococcus aureus Isolates

The Use of Molecular Methods for the Detection and Identification of Methicillin-Resistant Staphylococcus Aureus

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