In this study a total of 84 cases were identified through MALDI-TOF, 74 cases were inspected through VITEKⅡ automated identification equipment using EV6 and PCR method was carried out on 120 cases that were grown in EV6 liquid medium. 46 (38.3%) out of 120 cases, which PCR method was carried out from EV6 liquid medium and grown black, no vancomycin resistance gene was detected. Therefore, PCR method appeared to have many cases requiring unnecessary tests due to many false positives, although it is a quick and sensitive method.
In cases, which were only grown in EV4 and both in EV4 and EV6, no vancomycin resistance gene was detected or vanC results were shown based on PCR genotype results and in 56 cases, which were grown in all of EV4, EV6, EV12 and EV24, MALDI-TOF method utilizing EV6 and EV12 mediums was found to be able to distinguish vanC and Non-vanC VRE since they were confirmed to be strains that had vanA or vanA and vanC genotypes.
Comparing the total times taken, 3-4 days were taken to identify if identified through VITEKⅡ automated identification equipment after plate culture. On the other hand, 1-2 days were taken if cultured in a liquid medium and multiple polymerase chain reaction method was used, and 2 days were taken if identified through MALDI-TOF using Enteroccosel agar with newly designed 12㎍/mL vancomycin. Therefore, both methods were suitable for use as a quick screening test. However, multiple polymerase chain reaction method had too many false positives requiring unnecessary tests and more human resources and cost.
Based on the results of this study, compared to the method using EV medium with 6㎍/mL vancomycin, the method, which detects VRE identified through MALDI-TOF colony grown from Enteroccocel agar with additional 12㎍/mL vancomycin, have been identified to be the method that could be used quick and easy, as it could eliminate vanC and VRE and could also detect VanA and vanB strains equivalently compared to the culture method PCR method that is the most accurate existing VRE monitoring method. In addition, it is a clinically useful method in detecting non-vanC VRE that is important in hospital infection, as it is possible to verify appropriate phenotype and mycetoma.