배경: 한국 진료 현실과 Clinical and laboratory standards institute (CLSI) 권고에 보다 적합한 항균제 감수성 검사가 가능하 도록 Vitek 2 system에 사용되는 항균제 감수성 검사 카드의 항균제 조합이 조정된 한국형 카드가 출시되었다. 이 연구에 서는 그람음성 막대균의 항균제 감수성 카드인 한국형 AST N056과 AST N055 카드를 평가하였다. 방법: 기존형과 한국형 카드인 AST N041-AST N056 간의 동일한 항목인 15항목과 AST N022-AST N055 카드간의 17항목에 대해서는 기존 카드 및 한국형 카드의 결과에 대한 동일성 여부로 평가하였다. AST N056에 추가된 aztreonam, tobramycin, meropenem 및 AST N055 에 추가된 cefotaxime, levofloxacin, minocycline 등의 항균제들은 디스크 확산법을 시행하여 결과가 불일치하는 경우 Etest 또는 액체배지 희석법을 이용하여 확인하였다. 결과: AST N041-AST N056 카드간 비교에서는 균 하나당 불일치 항목 수가 0.34, minor error가 88.2%, major error와 very major error는 각각 5.9%였고, AST N022-AST055 카드간 비교에서 균 하나당 불일치 항목수는 1.23, very major error 4.4%를 보였다. 3개의 추가된 항균제 항목은 AST N055 카드에서 총 111검체에서 49항목(44.1%)의 높은 불일치를 보였고, very major error와 major error은 각각 5.9%, 2.0%이었다. 결론: 한국형 카드 AST N056은 기존 카드와 동일한 항목 및 추가된 항균제 항목에 있어서 대체적으로 일치하는 결과를 보였다. 상대적으로 높은 불일치를 보였던 AST N055의 경우, 추가된 세가지 항목의 결과 판독에 있어서 같은 계열 다른 항균제 항목의 결과를 참고하여야 하고, 기존 카드와 동일한 항목 간에 보인 높은 불일치는 한국의 임상균주를 이용한 표준법과의 비교평가가 이루어져야 된다고 사료되었다.

antimicrobial susceptibility cards for Vitek 2 system uses an adjusted antimicrobial combination that reflects Korean clinical practice and CLSI guidelines. We evaluated the two Korean antimicrobial susceptibility testing cards for gram negative rods, AST N056 and AST N055. Methods: The results of susceptibility tests were compared between the original and Korean cards. A number of the same antimicrobials included in the both cards were 15 in AST N041-AST N056 and 17 in AST N022-AST N055. Susceptibilities to the newly added antimicrobials, aztreonam, tobramycin, and meropenem for AST N056; and cefotaxime, levofloxacin, and minocycline for AST N055 were compared with those obtained by disc diffusion test and, in case of discrepancy, by confirmative Etest or broth dilution method. Results: In comparison between AST N041 and AST N056 cards, the average discrepancy rate per strain was 0.34, minor error was 88.2%, and major error and very major error were both 5.9%. In comparison between AST N022 and AST055 cards, the average discrepancy rate per strain and very major error were 1.23 and 4.4%, respectively. The three antimicrobial agents added into AST N055 card showed highly discrepant results as a total of 49 items (44.1%) in 111 isolates were discrepant with very major error of 5.9% and major error of 2.0%. Conclusion: AST N056 showed acceptable results in most items including the newly added antimicrobial agents. However, in the case of AST N055 card that showed a relatively high discrepancy, other indicator antibiotics should be referred to for newly added three antimicrobials. For the antibiotics that showed a high discrepancy between the original and Korean cards, a comparison study should be performed using the standard method and clinical isolates collected in Korea.

antimicrobial susceptibility cards for Vitek 2 system uses an adjusted antimicrobial combination that reflects Korean clinical practice and CLSI guidelines. We evaluated the two Korean antimicrobial susceptibility testing cards for gram negative rods, AST N056 and AST N055. Methods: The results of susceptibility tests were compared between the original and Korean cards. A number of the same antimicrobials included in the both cards were 15 in AST N041-AST N056 and 17 in AST N022-AST N055. Susceptibilities to the newly added antimicrobials, aztreonam, tobramycin, and meropenem for AST N056; and cefotaxime, levofloxacin, and minocycline for AST N055 were compared with those obtained by disc diffusion test and, in case of discrepancy, by confirmative Etest or broth dilution method. Results: In comparison between AST N041 and AST N056 cards, the average discrepancy rate per strain was 0.34, minor error was 88.2%, and major error and very major error were both 5.9%. In comparison between AST N022 and AST055 cards, the average discrepancy rate per strain and very major error were 1.23 and 4.4%, respectively. The three antimicrobial agents added into AST N055 card showed highly discrepant results as a total of 49 items (44.1%) in 111 isolates were discrepant with very major error of 5.9% and major error of 2.0%. Conclusion: AST N056 showed acceptable results in most items including the newly added antimicrobial agents. However, in the case of AST N055 card that showed a relatively high discrepancy, other indicator antibiotics should be referred to for newly added three antimicrobials. For the antibiotics that showed a high discrepancy between the original and Korean cards, a comparison study should be performed using the standard method and clinical isolates collected in Korea.