Agar diffusion, agar dilution, Etest®, and agar screening test in the detection of methicillin resistance in staphylococci

Rowe, Fabiana; Superti, Silvana; Scheibe, Rosane M.; Dias, Cícero

doi:10.1016/s0732-8893(02)00359-0

Cited by 15 publications

(15 citation statements)

References 15 publications

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“…This lack of specificity was expected due to the presence of 17 mecA-negative CoNS strains with MICs between 0.5 and 2 g/ml (11 S. saprophyticus strains, 5 Staphylococcus lugdunensis strains, and 1 Staphylococcus gallinarum strain). This phenomenon has been well described in the literature, mainly for S. saprophyticus strains (4,6,9,12). When the breakpoint defined by the CLSI was applied, the sensitivity and the specificity were 100% and 45%, respectively; three mecA-positive CoNS strains with MICs between 0.5 and 2 g/ml were correctly categorized.…”

supporting

confidence: 57%

Evaluation of Moxalactam with the BD Phoenix System for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci

et al. 2007

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The performance of moxalactam with the BD Phoenix system for the detection of methicillin resistance in coagulase-negative staphylococci was evaluated by use of a collection of 186 strains. Moxalactam was a better drug as an indicator of methicillin resistance for mecA-positive strains than oxacillin and cefoxitin were. For strains other than Staphylococcus saprophyticus, a moxalactam MIC >16 g/ml was indicative of methicillin resistance.

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supporting

confidence: 57%

Evaluation of Moxalactam with the BD Phoenix System for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci

et al. 2007

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“…Kohner and colleagues (17) proposed the use of 0.6 g of oxacillin per ml in the agar screening test on the basis of the 10-fold decrease in resistance breakpoints for CoNS isolates. A recent study (27) evaluated use of this concentration of oxacillin in the test. The investigators reported a poor correlation of the agar screening test results and mecA gene detection for all CoNS strains tested except those of S. epidermidis.…”

Section: Slide Latex Agglutination Resultsmentioning

confidence: 99%

“…Studies evaluating the performance of methods focusing on the phenotypic detection of oxacillin susceptibility in Brazilian CoNS isolates are scarce (5,27). Furthermore, a slide latex agglutination test for the detection of susceptibility had not previously been evaluated in Brazil.…”

mentioning

confidence: 99%

Coagulase-Negative Staphylococci: Comparison of Phenotypic and Genotypic Oxacillin Susceptibility Tests and Evaluation of the Agar Screening Test by Using Different Concentrations of Oxacillin

et al. 2003

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This study evaluated the oxacillin susceptibilities of 152 coagulase-negative staphylococcal (CoNS) strains of 12 species by disk diffusion; agar dilution; E-test; the slide latex agglutination test (Slidex MRSA Detection test; bioMérieux S/A, Paris, France); the agar screening test with 1, 2, 4, or 6 g of oxacillin per ml and incubation for 24 or 48 h; and detection of the mecA gene by PCR. The results revealed that the agar screening test with 4 g of oxacillin per ml and incubation for 48 h was superior to any single phenotype-based susceptibility assay, presenting a sensitivity and a specificity of 100% each. For the different methods evaluated, the sensitivities and specificities were as follows: for disk diffusion, 94.2 and 91.8%, respectively; for the agar dilution test 100 and 73.5%, respectively; for E-test, 100 and 71.4%, respectively; and for the slide latex agglutination test, 97.1 and 98%, respectively. A good correlation was observed between oxacillin susceptibility testing results and PCR results for Staphylococcus epidermidis, S. haemolyticus, S. hominis subsp. hominis, and all mecA-positive strains. However, at least 60% of the mecA-negative isolates of the species S. saprophyticus, S. cohnii subsp. urealyticum, S. lugdunensis, and S. sciuri were erroneously classified as oxacillin resistant by the agar dilution test. Conversely, the slide latex agglutination test presented a high sensitivity (97.1%) and a high specificity (98%) for all CoNS species. Our results demonstrated the accuracy of the agar screening test with 4 g of oxacillin per ml and incubation for 48 h and the slide latex agglutination test for the appropriate detection of the oxacillin susceptibilities of CoNS isolates. Both assays are technically simple and can be easier to perform in routine laboratories than PCR.

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“…PBP2a has been found in a variety of CoNS, but expression of mecA is different in CoNS and Staphylococcus aureus. Several groups of investigators have described DNA probes [5][6][7] and PCR assays [8][9][10][11][12][13][14][15][16] for detection of oxacillin resistance in staphylococci. Based on the results of some of these studies, the National Committee for Clinical Laboratory Standards (NCCLS) has redefined the breakpoints for oxacillin susceptibility in CoNS [17].…”

mentioning

confidence: 99%

Comparison of PCR detection of mecA with agar dilution and Etest for oxacillin susceptibility testing in clinical isolates of coagulase-negative staphylococci

Tveten

Jenkins

Digranes

et al. 2004

Clinical Microbiology and Infection

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Oxacillin-resistant staphylococci are heterogeneous in their expression of resistance to beta-lactam antibiotics. Different recommendations regarding screening methods for routine use have been published. In this study, the susceptibility to oxacillin of 232 coagulase-negative staphylococci (CoNS) was determined by agar dilution, Etest and presence of the mecA gene. When an oxacillin resistance breakpoint of > or = 0.5 mg/L was used, the sensitivity and specificity for agar dilution were 97.6% and 100%, and those for Etest were 100% and 95.4%. The current National Committee for Clinical Laboratory Standards oxacillin breakpoint recommendation will categorise accurately the CoNS species encountered commonly.

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Agar diffusion, agar dilution, Etest®, and agar screening test in the detection of methicillin resistance in staphylococci

Cited by 15 publications

References 15 publications

Evaluation of Moxalactam with the BD Phoenix System for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci

Evaluation of Moxalactam with the BD Phoenix System for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci

Coagulase-Negative Staphylococci: Comparison of Phenotypic and Genotypic Oxacillin Susceptibility Tests and Evaluation of the Agar Screening Test by Using Different Concentrations of Oxacillin

Comparison of PCR detection of mecA with agar dilution and Etest for oxacillin susceptibility testing in clinical isolates of coagulase-negative staphylococci

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