Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan.
Antimicrob Resist Infect Control. 2020 May 11;9(1):62. doi: 10.1186/s13756-020-00731-8.
Burden of aspergillosis is reported to be significant from developing countries including those in South Asia. The estimated burden in Pakistan is also high on the background of tuberculosis and chronic lung diseases. There is concern for management of aspergillosis with the emergence of azole resistant Aspergillus species in neighbouring countries in Central and South Asia. Hence the aim of this study was to screen significant Aspergillus species isolates at the Microbiology Section of Aga Khan Clinical Laboratories, Pakistan, for triazole resistance.
A descriptive cross-sectional study, conducted at the Aga Khan University Laboratories, Karachi, from September 2016-May 2019. One hundred and fourteen, clinically significant Aspergillus isolates [A. fumigatus (38; 33.3%), A. flavus (64; 56.1%), A. niger (9; 7.9%) A. terreus (3; 2.6%)] were included. The clinical spectrum ranged from invasive aspergillosis (IA) (n = 25; 21.9%), chronic pulmonary aspergillosis (CPA) (n = 58; 50.9%), allergic bronchopulmonary aspergillosis (ABPA) (n = 4; 3.5%), severe asthma with fungal sensitization (SAFS) (n = 4; 3.5%), saprophytic tracheobronchial aspergillosis (n = 23; 20.2%). Screening for triazole resistance was performed by antifungal agar screening method. The minimum inhibitory concentration (MIC) of 41 representative isolates were tested and interpreted according to the Clinical and Laboratory Standards Institute broth microdilution method.
All the isolates were triazole-susceptible on agar screening. MICs of three azole antifungals for 41 tested isolates were found to be ≤1 ml/L; all isolates tested were categorized as triazole-susceptible, including 4 isolates from patients previously on triazole therapy for more than 2 weeks. The minimum inhibitory concentration required to inhibit the growth of 90% organisms (MIC) of itraconazole, voriconazole and posaconazole of the representative Aspergillus isolates was 1 mg/L, 1 mg/L and 0.5 mg/L, respectively.
Triazole resistance could not be detected amongst clinical Aspergillus isolates from the South of Pakistan. However, environmental strains remain to be tested for a holistic assessment of the situation. This study will set precedence for future periodic antifungal resistance surveillance in our region on Aspergillus isolates.
据报道，包括南亚国家在内的发展中国家的曲霉菌病负担很大。在结核病和慢性肺部疾病的背景下，巴基斯坦的估计负担也很高。由于在中亚和南亚的邻国出现了唑类耐药的曲霉菌种，因此人们对曲霉菌病的治疗感到担忧。因此，本研究的目的是在巴基斯坦 Aga Khan 临床实验室的微生物科筛选具有重要意义的曲霉菌种，以检测唑类耐药性。
这是一项描述性的横断面研究，于 2016 年 9 月至 2019 年 5 月在卡拉奇的 Aga Khan 大学实验室进行。共纳入 114 株临床意义重大的曲霉菌分离株[烟曲霉（38；33.3%）、黄曲霉（64；56.1%）、黑曲霉（9；7.9%）、土曲霉（3；2.6%）]。临床谱从侵袭性曲霉病（IA）（n=25；21.9%）、慢性肺曲霉病（CPA）（n=58；50.9%）、变应性支气管肺曲霉病（ABPA）（n=4；3.5%）、伴有真菌致敏的严重哮喘（SAFS）（n=4；3.5%）、腐生性气管支气管曲霉病（n=23；20.2%）。通过抗真菌琼脂筛选法进行唑类耐药性筛选。根据临床和实验室标准协会肉汤微量稀释法，对 41 株代表性分离株的最低抑菌浓度（MIC）进行了检测和解释。
琼脂筛选显示所有分离株均对唑类敏感。对 41 株测试分离株的三种唑类抗真菌药物的 MIC 发现均≤1ml/L；所有测试的分离株均被归类为唑类敏感，包括 4 株来自先前接受唑类治疗超过 2 周的患者的分离株。代表性曲霉菌分离株的伊曲康唑、伏立康唑和泊沙康唑的最低抑菌浓度（MIC）分别为 1mg/L、1mg/L 和 0.5mg/L。
无法在巴基斯坦南部的临床曲霉菌分离株中检测到唑类耐药性。然而，仍需对环境株进行测试，以全面评估情况。本研究将为我们地区未来定期进行的曲霉菌分离物抗真菌耐药性监测奠定基础。
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