Janani R Sruti, Xess Immaculata, Das Bimal Kumar, Cs Saumya, Bordoloi Tamanna, Pandey Mragnayani, Ahmed Jaweed, Singh Gagandeep
All India Institute of Medical Sciences, New Delhi, India.
Indian J Med Microbiol. 2024 Sep-Oct;51:100708. doi: 10.1016/j.ijmmb.2024.100708. Epub 2024 Aug 23.
& objective: The existence of visually identical cryptic Aspergillus species that can be distinguished only by molecular techniques is becoming more widely acknowledged. For the majority of antifungal drugs, these are known to exhibit a greater minimal inhibitory concentration in vitro. For the purpose of receiving the proper care, it is crucial to identify these species at right time. Our aim in this work is to identify and describe the Aspergillus species that are cryptic from all of the clinical samples.
Routine samples from inpatients and outpatients received in department of Microbiology, All India Institute of Medical Sciences, New Delhi, showing growth of Aspergillus species were included in this study. Phenotypic and Matrix Assisted Laser Desorption Ionisation - Time of Flight identified isolates were analysed for cryptic species, by PCR and ITS/ß - tubulin sequencing. In accordance with CLSI recommendations, antifungal susceptibility testing was conducted using micro broth dilution.
Of the 94 isolates, 54 A. fumigatus, 34 A. flavus, 3 A. nidulans, 2 A. terreus, and 1 A. niger were morphologically identified. MALDI-TOF misidentified 2 A. nidulans isolates and 1 A, stellatus isolate. The ß - tubulin sequence analysis revealed that 2 isolates (2.08 %) were cryptic, one was A. stellatus and another one was A. tubingensis.
形态上无法区分、只能通过分子技术加以鉴别的隐球菌种类的存在，正得到越来越广泛的认可。对于大多数抗真菌药物而言，已知这些种类在体外表现出更高的最低抑菌浓度。为了获得恰当的治疗，及时鉴别这些种类至关重要。我们这项研究的目的是从所有临床样本中鉴别并描述隐球菌种类。
本研究纳入了新德里全印度医学科学研究所微生物科接收的住院患者和门诊患者的常规样本，这些样本显示有曲霉菌生长。对通过表型和基质辅助激光解吸电离飞行时间质谱鉴定的分离株，采用聚合酶链反应（PCR）和内转录间隔区/β-微管蛋白测序分析其隐球菌种类。按照美国临床和实验室标准协会（CLSI）的建议，采用微量肉汤稀释法进行抗真菌药敏试验。
在94株分离株中，形态学鉴定出54株烟曲霉、34株黄曲霉、3株构巢曲霉、2株土曲霉和1株黑曲霉。基质辅助激光解吸电离飞行时间质谱错误鉴定了2株构巢曲霉分离株和1株星状曲霉分离株。β-微管蛋白序列分析显示，有2株分离株（2.08%）为隐球菌，一株是星状曲霉，另一株是管囊曲霉。
