根據 Carbapenem-resistant Klebsiella pneumoniae 的抗藥性表現型預測是否存在 Klebsiella pneumoniae Carbapenemase

Use of Antibiotic Sensitivity Test to Predict the Presence of Klesiella pneumoniae Carbapenemase in Carbapenem-resistant Klebsiella pneumoniae

本研究企圖藉由 carbapenem-resistant Klebsiella pneumoniae （CRKP） 的抗藥性表現型（phenotype），以預測抗藥性機轉是否藉由 K. pneumoniae carbapenemase （KPC）的可能性，以達到更快採取感染管制措施，減少菌株散播的目的。在南部的某區域醫院，收集自2011年8月1日到2017年5月30日，由實驗室通報疾病管制署carbapenem-resistant Enterobactericeae （CRE） 抗藥性檢測的K. pneumoniae個案。抗生素敏感性試驗以紙錠瓊脂擴散法及利用Phoenix自動化偵測儀測試菌株之最低抑菌濃度，並根據Clinical and Laboratory Standards Institute （CLSI）建議的準則進行判讀，而菌株是否存在KPC則由疾病管制署的檢測報告做為依據。總共有88株CRKP菌株，其中22株是KPC-CRKP，另外66株為non-KPC-CRKP。若以單獨imipenem、meropenem或同時imipenem 與meropenem的抑制環≤ 6mm來預測菌株是 KPC-CRKP 的特異性及陽性預測值分別為96.9%、96.9%、96.9%及88.8%、90.4%、88.8%。如果以單獨imipenem、meropenem或同時imipenem與meropenem的MIC ≥ 8 μg/mL來預測菌株是 KPC-CRKP的特異性及陽性預測值分別為74.2%、89.3%、89.3%及56.4%、75.8%、75.8%。如果以imipenem、或meropenem的MIC ≤4 μg/mL來預測菌株是 KPC-CRKP 的敏感性均為0%。根據此研究，對於CRKP菌株，如果存在meropenem抑制環≤ 6mm或MIC ≥ 8 μg/mL同時參考改良賀治試驗呈現陽性結果，可以預測是KPC-CRKP的機率大於 95%。因此，我們建議臨床實驗室一旦分離出此抗藥性表現型的CRKP菌株，應該立即通知感染管制室，立即採取嚴格的感染管制措施，以避免KPC-CRKP進一步的散播。

This study aims to characterize whether Klebsiella pneumoniae carbapenemase (KPC) is involved in carbapenem-resistant K. pneumoniae (CRKP) antibiotic resistant. At a regional hospital in Southern Taiwan, all nonduplicated CRKP from 1 August 2011 to 30 May 2017 were collected from clinical laboratory reported to Centers for Disease Control (CDC), Taiwan. Antimicrobial susceptibility testing was performed by disk diffusion methods and minimal inhibitory concentration (MIC) was performed by using the Phoenix automation microbiology system. The interpretive criteria were according to Clinical and Laboratory Standards Institute (CLSI) 2016. All confirmed KPC-CRKP strains were according to the reports of CDC, Taiwan. Totally, 88 CRKP strains were enrolled in this study, including 22 KPC-CRKP strains and 66 non-KPC-CRKP strains. While the zone diameter ≤ 6mm in imipenem, meropenem, imipenem and meropenem was interpreted as KPC-CRKP, the specificity and positive predictive value (PPV) were 96.9%、96.9%、96.9% and 88.8%、90.4%、 88.8%, respectively. In the MIC ≥ 8 μg/mL from imipenem, meropenem, imipenem and meropenem to predict for KPC-CRKP, the specificity and PPV were 74.2%、89.3%、89.3% and 56.4%、75.8%、 75.8%, respectively. By contrast, in the MIC ≤4 μg/mL of imipenem or meropenem for KPC-CRKP, both the sensitivity rate were 0%. Briefly, for CRKP strains, if they had a zone diameter ≤ 6mm of meropenem or meropenem MIC ≥ 8 μg/mL, together with positive result of Modified Hodge test, the probability of the strains being KPC-CRKP were more than 95%. This approach can efficiently diagnose KPC-CRKP.