Asner Sandra A, Giulieri Stefano, Diezi Manuel, Marchetti Oscar, Sanglard Dominique
Pediatric Infectious Diseases and Vaccinology Unit, Department of Paediatrics, University Hospital Center, Lausanne, Switzerland Service of Infectious Diseases, Department of Internal Medicine, University Hospital Center, Lausanne, Switzerland.
Service of Infectious Diseases, Department of Internal Medicine, University Hospital Center, Lausanne, Switzerland.
Antimicrob Agents Chemother. 2015 Dec;59(12):7715-22. doi: 10.1128/AAC.02204-15. Epub 2015 Oct 5.
Candida lusitaniae is usually susceptible to echinocandins. Beta-1,3-glucan synthase encoded by FKS genes is the target of echinocandins. A few missense mutations in the C. lusitaniae FKS1 hot spot 1 (HS1) have been reported. We report here the rapid emergence of antifungal resistance in C. lusitaniae isolated during therapy with amphotericin B (AMB), caspofungin (CAS), and azoles for treatment of persistent candidemia in an immunocompromised child with severe enterocolitis and visceral adenoviral disease. As documented from restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) analysis, the five C. lusitaniae isolates examined were related to each other. From antifungal susceptibility and molecular analyses, 5 different profiles (P) were obtained. These profiles included the following: profile 1 (P1) (CAS MIC [μg/ml], 0.5; fluconazole [FLC] MIC, 0.25), determined while the patient was being treated with liposomal AMB for 3 months; P2 (FLC MIC [μg/ml], 0.25; CAS MIC, 4), while the patient was being treated with CAS for 2 weeks; P3 (CAS MIC [μg/ml], 0.5; FLC MIC, 32), while the patient was being treated with azoles and CAS initially followed by azoles alone for a week; P4 (CAS MIC [μg/ml], 8; FLC MIC, 8), while the patient was being treated with both drugs for 3 weeks; and P5 (AMB MIC [μg/ml], 0.125; CAS MIC, 8), while the patient was being treated with AMB and FLC for 2 weeks. CAS resistance was associated with resistance not only to micafungin and anidulafungin but also to AMB. Analysis of CAS resistance revealed 3 novel FKS1 mutations in CAS-resistant isolates (S638Y in P2; S631Y in P4; S638P in P5). While S638Y and -P are within HS1, S631Y is in close proximity to this domain but was confirmed to confer candin resistance using a site-directed mutagenesis approach. FLC resistance could be linked with overexpression of major facilitator gene 7 (MFS7) in C. lusitaniae P2 and P4 and was associated with resistance to 5-flurocytosine. This clinical report describes resistance of C. lusitaniae to all common antifungals. While candins or azole resistance followed monotherapy, multidrug antifungal resistance emerged during combined therapy.
葡萄牙念珠菌通常对棘白菌素敏感。由FKS基因编码的β-1,3-葡聚糖合酶是棘白菌素的作用靶点。已报道葡萄牙念珠菌FKS1热点1（HS1）中有一些错义突变。我们在此报告了在一名患有严重小肠结肠炎和内脏腺病毒病的免疫受损儿童治疗持续性念珠菌血症期间，用两性霉素B（AMB）、卡泊芬净（CAS）和唑类药物治疗时分离出的葡萄牙念珠菌迅速出现抗真菌耐药性的情况。根据限制性片段长度多态性（RFLP）和随机扩增多态性DNA（RAPD）分析记录，所检测的5株葡萄牙念珠菌分离株相互关联。通过抗真菌药敏试验和分子分析，获得了5种不同的谱型（P）。这些谱型包括：谱型1（P1）（CAS MIC[μg/ml]，0.5；氟康唑[FLC]MIC，0.25），是在患者接受脂质体AMB治疗3个月时测定的；P2（FLC MIC[μg/ml]，0.25；CAS MIC，4），是在患者接受CAS治疗2周时测定的；P3（CAS MIC[μg/ml]，0.5；FLC MIC，32），是在患者最初接受唑类和CAS治疗，随后单独接受唑类治疗1周时测定的；P4（CAS MIC[μg/ml]，8；FLC MIC，8），是在患者接受两种药物治疗3周时测定的；P5（AMB MIC[μg/ml]，0.125；CAS MIC，8），是在患者接受AMB和FLC治疗2周时测定的。CAS耐药不仅与对米卡芬净和阿尼芬净的耐药有关，还与对AMB的耐药有关。对CAS耐药性的分析揭示了在CAS耐药分离株中有3种新的FKS1突变（P2中的S638Y；P4中的S631Y；P5中的S638P）。虽然S638Y和-S638P在HS1内，但S631Y靠近该结构域，但使用定点诱变方法证实其赋予了对棘白菌素的耐药性。FLC耐药可能与葡萄牙念珠菌P2和P4中主要易化子基因7（MFS7）的过表达有关，并且与对5-氟胞嘧啶的耐药有关。本临床报告描述了葡萄牙念珠菌对所有常见抗真菌药物的耐药情况。虽然单药治疗后出现了对棘白菌素或唑类的耐药，但联合治疗期间出现了多药抗真菌耐药性。
