Comparison of Eight Methods To Detect Vancomycin Resistance in Enterococci

Endtz, Hubert P.; Braak, Nicole van den; Belkum, Alex van; Goessens, W. H. F.; Kreft, Deborah; Stroebel, Adam B.; Verbrugh, Henri A.

doi:10.1128/jcm.36.2.592-594.1998

Cited by 53 publications

(28 citation statements)

References 15 publications

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“…In addition, the agar screen method using VRE screen agar supplemented with vancomycin (Nippon Becton Dickinson and Company, Ltd.) at a final concentration of 6 g/ml exceptionally allowed the growth of all the VRE strains investigated. It is very encouraging that both the sensi-disk method and the agar screen method correctly identified all of the 20 VRE strains examined, thus confirming the results of some recent evaluation studies (3,15,16), but these tests were time-consuming nevertheless.…”

supporting

confidence: 82%

Limitations of Vitek GPS-418 Cards in Exact Detection of Vancomycin-Resistant Enterococci with the vanB Genotype

et al. 2000

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The susceptibilities of 20 strains of vancomycin-resistant enterococci (VRE) with the vanB genotype obtained by using Vitek GPS-418 cards were compared with those obtained by the broth dilution method of the National Committee for Clinical Laboratory Standards (NCCLS) (approved standard M7-A4) and with those obtained by the agar screen method using bile esculin azide agar containing 6 g of vancomycin per ml. Although both the broth dilution and agar screen methods disclosed no discordance, Vitek GPS-418 cards yielded a very major error compared with the results obtained by the reference broth dilution method of the NCCLS. Vitek GPS-418 cards were therefore found to have considerable room for improvement for the accurate detection of vanB VRE strains.

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supporting

confidence: 82%

Limitations of Vitek GPS-418 Cards in Exact Detection of Vancomycin-Resistant Enterococci with the vanB Genotype

et al. 2000

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“…In an earlier study, Endtz and coworkers evaluated the accuracy of eight available susceptibility testing methods on 50 vanA, 15 vanB, 50 vanC1 and 30 vanC2 VREs [5]. VRE isolates containing the vanA gene were detected by all methods.…”

Section: Resultsmentioning

confidence: 99%

“…E-test and the agar screen methods were able to detect all VRE isolates. The investigation by Endtz and coworkers [5], however, did not evaluate the e¡ect of plating medium on the antibiotic susceptibility testing methods. In our study, the e¡ectiveness of MH, MHB or BHI medium was evaluated on the vancomycin susceptibility using the disk di¡usion, broth dilution and E-test methods, and the data were correlated with the presence of van genes.…”

Section: Resultsmentioning

confidence: 99%

“…Accurate and prompt detection of VRE and determination of their antimicrobial susceptibility pro¢les by clinical laboratories are necessary to prevent and control nosocomial outbreaks allowing patients to be administered appropriate drugs. Several studies have been conducted to validate the accuracy of antimicrobial susceptibility testing of VRE [4,5]. The composition of plating/broth medium and the growth conditions of enterococcal isolates may in£uence the antibiotic susceptibility pro¢les and the minimum inhibitory concentration (MIC) values [6,7].…”

Section: Introductionmentioning

confidence: 99%

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Influence of growth media on vancomycin resistance of Enterococcus isolates and correlation with resistance gene determinants

Nayak¹

2002

FEMS Microbiology Letters

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The effect of Mueller^Hinton (MH), MH+blood or brain heart infusion medium (agar or broth) on 13 Enterococcus isolates was determined, when testing their antibiotic susceptibility. Disk diffusion and Vitek methods were used to determine vancomycin resistance, while broth dilution and E-test methods were used to measure the minimum inhibitory concentration. The data were correlated with the presence of vancomycin resistance genes. A definite correlation pattern could not be established between the presence of van genes and vancomycin resistance in any plating medium, when tested by the disk diffusion assay. The broth dilution, irrespective of the plating medium, and Vitek methods were more reliable than the E-test method in testing isolates with vanA or vanB genes. However, for vanC2/ C3 genotypes, the E-test method, irrespective of the plating medium, tested better than the broth dilution assay. ß

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“…The majority of these authors, however, reported no problems in cases of the high-level glycopeptide resistance type VanA. Concerning the Etest, there are different experiences reported in the literature: Endtz et al [13] could detect all enterococci correctly, including the VanB-and VanC-type GRE; in contrast, Schulz and Sahm [16] reported that the Etest must be interpreted with caution in these enterococcal species. It remains open whether the laboratories participating in our study correctly followed the manufacturer's recommendations for the Etest with regard to the bacterial inoculum and the time of incubation (at least 24 h).…”

Section: --(100)mentioning

confidence: 97%

Identification of enterococci and determination of their glycopeptide resistance in German and Austrian clinical microbiology laboratories

Klare

Badstübner

Konstabel

et al. 1999

Clinical Microbiology and Infection

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OBJECTIVE: To determine exactly how German and Austrian routine laboratories perform tests for the identification of enterococci and determination of their glycopoptide resistance. METHODS: Six enterococcal test strains with different types of glycopeptide resistance (Enterococcus faecium, VanA; E. faecalis, VanA; E. faecium, VanB; E. faecalis, VanB; E. gallinarum, VanC1; E. casseliflavus, VanC2) were sent as anonymous isolates to 73 clinical microbiology laboratories (65 in Germany; eight in Austria). The participating laboratories had to identify the strains up to the species level and to determine their antibiotic susceptibilities to the glycopeptides vancomycin and teicoplanin by the test method(s) that are used daily in the corresponding laboratories. RESULTS: The analysis of the results received from 62 laboratories (56 from Germany, six from Austria) demonstrated that the most used routine method in susceptibility testing was the agar diffusion test, followed by the Etest, and the microbroth dilution procedure. The majority of participants had no difficulties in susceptibility testing with the VanA-type strains. However, the agar diffusion test was often not able to recognize clearly the VanB and VanC strains; some problems also arose with VanB isolates in the Etest. With the microbroth dilution method, the corresponding type of glycopeptide resistance was correctly determined in the majority of enterococcal test strains. Difficulties also arose in identification, especially with the VanC strains (E. gallinarum and E. casseliflavus), which were often falsely identified as E. faecium. The reasons for these errors are obviously based on the lack of important tests (such as motility and presence of a yellow pigment) in some commercially available identification test kits.

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Comparison of Eight Methods To Detect Vancomycin Resistance in Enterococci

Cited by 53 publications

References 15 publications

Limitations of Vitek GPS-418 Cards in Exact Detection of Vancomycin-Resistant Enterococci with the vanB Genotype

Limitations of Vitek GPS-418 Cards in Exact Detection of Vancomycin-Resistant Enterococci with the vanB Genotype

Influence of growth media on vancomycin resistance of Enterococcus isolates and correlation with resistance gene determinants

Identification of enterococci and determination of their glycopeptide resistance in German and Austrian clinical microbiology laboratories

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