Evaluation of different methods for detecting methicillin (oxacillin) resistance in Staphylococcus aureus

Velasco, David; Tomás, María; Cartelle, Mónica; Beceiro, Alejandro; Pérez, Astrid; Molina, Francisca; Moure, Raquel; Villanueva, Rosa; Bou, Germán

doi:10.1093/jac/dki017

Cited by 158 publications

(137 citation statements)

References 9 publications

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“…Accuracy and promptness in the detection of meticillin resistance are of key importance in ensuring correct antibiotic treatment in infected patients and control of MR staphylococci in the hospital environment (Velasco et al, 2005). MR staphylococci have also emerged as a frequent cause of community-acquired infections (Naimi et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Cefoxitin disc diffusion test for detection of meticillin-resistant staphylococci

Jain

Agarwal

Verma

2008

Journal of Medical Microbiology

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Staphylococci are the main causative agents of nosocomial diseases. Over the last few years, the increase in the number of meticillin-resistant (MR) staphylococci has become a major clinical problem. Accuracy and promptness in the detection of meticillin resistance are of key importance in ensuring the correct antibiotic treatment in infected patients and control of MR staphylococci in the hospital environment. This study evaluated the accuracy of a cefoxitin disc diffusion (DD) test for the detection of meticillin resistance in staphylococci. A total of 144 clinical isolates [97 Staphylococcus aureus and 47 coagulase-negative staphylococci (CoNS)] were tested using a mecA gene PCR, a DD test (oxacillin, 1 mg disc; cefoxitin, 30 mg disc), determination of oxacillin MIC by agar dilution (AD), and an oxacillin screen agar test at oxacillin concentrations of 4 and 6 mg ml "1 . Of the 97 S. aureus and 47 CoNS isolates, 73 (75.26 %) and 30 (63.83 %), respectively, were mecA-positive. The sensitivity and specificity of the cefoxitin DD test were 94.44 and 95.83 %, respectively, for S. aureus and 80 and 100 %, respectively, for CoNS. The oxacillin DD method was 100 % sensitive and 58.33 % specific for S. aureus, and 86.67 % sensitive and 70.59 % specific for CoNS. The AD test was highly sensitive (98.63 %) and specific (98.53 %) for S. aureus and CoNS (83.33 % sensitive and 94.12 % specific). The cefoxitin DD test for meticillin-resistance detection was more specific but less sensitive than the oxacillin DD test. Use of DD tests for both cefoxitin and oxacillin can help in more accurate prediction of meticillin resistance. Centres that are not equipped to carry out PCR can use AD methods for confirmation of meticillin resistance, especially in oxacillin-resistant and cefoxitin-sensitive cases.

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Section: Introductionmentioning

confidence: 99%

Cefoxitin disc diffusion test for detection of meticillin-resistant staphylococci

Jain

Agarwal

Verma

2008

Journal of Medical Microbiology

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“…Oxacillin-disk diffusion has been the traditional method for methicillin-resistance routine screening; but recently good accuracy of the cefoxitin disk for predicting methicillin resistance has been reported [4][5][6][7][8][9][10][11], and CLSI (Clinical and Laboratory Standards Institute) has recommended that cefoxitin should be preferred over oxacillin for the detection of mecA-mediated resistance [4]. However, the choice of the best phenotypic method for detecting methicillin resistance in S. aureus remains controversial.…”

mentioning

confidence: 99%

Detection of methicillin resistance in Staphylococcus aureus isolated from pediatric patients: is the cefoxitin disk diffusion test accurate enough?

Mimica¹,

Berezin²,

Carvalho

et al. 2007

Braz J Infect Dis

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We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100% sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92%, respectively, and 98% specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98%, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.

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“…Other available routine tests include epsilometer test and oxacillin agar screening plate. Although recommended by guidelines and validated in multiple studies [1][2][3][4][5][6]8,[12][13][14][15]17,18 , there is a lack of data about the accuracy of these tests in isolates from such a specific population as cystic fibrosis patients.…”

Section: Resultsmentioning

confidence: 99%

“…There are several studies in the biomedical literature regarding different oxacillin phenotypic susceptibility tests for S. aureus 1,2,[4][5][6]8,[12][13][14][15]17,18 , but, to our knowledge, none has included only cystic fibrosis isolates. Thus, the aim of the present study was to determine the accuracy of phenotypic oxacillin susceptibility methods in Staphylococcus aureus cystic fibrosis isolates with different SCCmec types.…”

Section: Introductionmentioning

confidence: 99%

Comparison of five methods for oxacillin susceptibility testing of Staphylococcus aureus isolates from cystic fibrosis patients

Mimica

Carvalho

Berezin

et al. 2012

Rev. Inst. Med. trop. S. Paulo

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SUMMARYMethicillin-resistant Staphylococcus aureus (MRSA) are now a worldwide problem. Cystic fibrosis (CF) patients are commonly colonized and infected by MRSA. Accurate oxacillin susceptibility testing is mandatory for the adequate management of these patients. We performed a comparison of the accuracy of different tests in CF isolates, including methicillin-susceptible S. aureus and MRSA with different SCCmec types, and using the mecA gene as the gold-standard. The sensitivity and specificity of oxacillin disc, Etest, and oxacillin agar screening plate were 100%. Sensitivity of the cefoxitin disc was 85% and specificity was 100%. For clinically relevant isolates, laboratories may consider the use of a combination of two phenotypic methods.

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Evaluation of different methods for detecting methicillin (oxacillin) resistance in Staphylococcus aureus

Abstract: In the absence of availability of molecular biology techniques, the cefoxitin disc was the best predictor of methicillin resistance in S. aureus from among the techniques tested.

Cited by 158 publications

References 9 publications

Cefoxitin disc diffusion test for detection of meticillin-resistant staphylococci

Cefoxitin disc diffusion test for detection of meticillin-resistant staphylococci

Detection of methicillin resistance in Staphylococcus aureus isolated from pediatric patients: is the cefoxitin disk diffusion test accurate enough?

Comparison of five methods for oxacillin susceptibility testing of Staphylococcus aureus isolates from cystic fibrosis patients

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