2017年至2023年臺灣Candida auris菌株鑑定及藥物敏感性

近年耳念珠菌（Candida auris）在全球崛起，且基於其高死亡率的侵襲感染、多重抗藥性、院內傳播的潛力，已對全球醫療保健系統構成了重大威脅。準確、高效率的耳念珠菌鑑定及藥物敏感性識別對於病患治療及疫情控制至關重要。
本文描述2017年至2023年間所收集全國24株疑似C. auris菌株，以MALDI-TOF、ITS1-5.8S-ITS2基因和28S r DNA（D1/D2）基因定序三種方法進行菌種鑑定：2株為Candida auris，14株為Candida haemulonii，6株為Candida duobushaemulonii，1株為Candida lusitamoae，1株為Candida parapsilosis。針對2株Candida auris進行amphotericin B、fluconazole、itraconazole、voriconazole、posaconazole、flucytosine、caspofungin、micafungin和anidulafungin 9種抗真菌藥的抗真菌敏感性檢測。結果顯示針對9種抗真菌藥（包括美國疾病管制與預防中心（Centers for Disease Control and Prevention, CDC）藥敏判斷標準的5種抗真菌藥amphotericin B、fluconazole、caspofungin、micafungin和anidulafungin）中除1株最低抑菌濃度（Minimum Inhibitory Concentration, MIC）呈現caspofungin抗藥性（8μg/ml）外均無抗藥性，且抗真菌藥抗藥性基因ERG11及FKS1亦未發現抗藥性位點之突變。該株疑似caspofungin抗藥性菌株，綜合考量其抗藥性基因未發生突變、其他棘白菌素（echinocandins）藥物MIC偏低及可能Eagle effect的影響，未將該株列為caspofungin抗藥性。多篇前人研究亦顯示MIC的判斷仍有其侷限性，抗藥性研判除依美國CDC建議的判斷基準外，應謹慎詮釋結果並輔助以抗藥性基因檢測方法。

In recent years, Candida auris infections had risen globally, and posed a major threat to the global healthcare system because of its high mortality rate of invasive infection, multi-drug resistance, and potential for nosocomial transmission. Accurate and efficient identification of C. auris and determination of their antifungal susceptibility are crucial for patient treatment and epidemic control.
We collected 24 suspected C. auris isolates across the country from 2017 to 2023 and identified them using MALDI-TOF, ITS1-5.8S-ITS2 gene, and 28S rRNA gene sequencing. The identification results were 2 C. auris, 14 C. haemulonii, 6 C. duobushaemulonii, 1 C. lusitamoae, and 1 C. parapsilosis. Antifungal susceptibility testing for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, flucytosine, caspofungin, micafungin, and anidulafungin were carried out against the 2 strains of C. auris. Among these, determination of resistance to amphotericin B, fluconazole, caspofungin, micafungin, and anidulafungin followed the susceptibility criteria from the US Centers for Disease Control and Prevention (US CDC). There were no drug resistance found, except one strain with MIC showing caspofungin resistance (8μg/ml). Considering that the resistance genes ERG11 and FKS1 of this suspected caspofungin-resistant strain had not mutated, the MIC of other echinocandins was low, and possible Eagle effect, this strain was not classified as caspofungin-resistant. Many previous studies have also shown that determining drug resistance using MIC still has limitations. In addition to using the criteria recommended by US CDC, drug resistance determination should be interpreted with caution and supplemented by drug resistance gene detection methods.