Comparison of molecular and MALDI-TOF MS identification and antifungal susceptibility of clinical Fusarium isolates in Southern China

Penghao Guo; Jianlong Chen; Yiwei Tan; Li Xia; Weizheng Zhang; Xiaojie Li; Yujie Jiang; Ruiying Li; Chunmei Chen; Kang Liao; Yaqin Peng

doi:10.3389/fmicb.2022.992582

Comparison of molecular and MALDI-TOF MS identification and antifungal susceptibility of clinical Fusarium isolates in Southern China

Front Microbiol. 2022 Sep 20:13:992582. doi: 10.3389/fmicb.2022.992582. eCollection 2022.

Authors

Penghao Guo¹, Jianlong Chen¹, Yiwei Tan², Li Xia³, Weizheng Zhang⁴, Xiaojie Li⁵, Yujie Jiang⁶, Ruiying Li⁷, Chunmei Chen⁸, Kang Liao¹, Yaqin Peng¹

Affiliations

¹ Department of Clinical Laboratory, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
² Department of Clinical Laboratory, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China.
³ Department of Clinical Laboratory, Jieyang People's Hospital, Jieyang, China.
⁴ Department of Clinical Laboratory, Guangzhou No.11 People's Hospital, Guangzhou, China.
⁵ Department of Clinical Laboratory, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
⁶ Department of Clinical Laboratory, Central Hospital of Guangdong Nongken, Zhanjiang, China.
⁷ Department of Clinical Laboratory, The First Affiliated Hospital, Guangdong Pharmaceutical University, Guangzhou, China.
⁸ Department of Clinical Laboratory, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, China.

Abstract

Background: Fusarium species are opportunistic causative agents of superficial and disseminated human infections. Fast and accurate identification and targeted antifungal therapy give help to improve the patients' prognosis.

Objectives: This study aimed to evaluate the effectiveness of matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS) for Fusarium identification, and investigate the epidemiology and antifungal susceptibility profiles of clinical Fusarium isolates in Southern China.

Methods: There were 95 clinical Fusarium isolates identified by DNA sequencing of translation elongation factor 1-alpha (TEF1α) and MALDI-TOF MS, respectively. Antifungal susceptibility testing of isolates was performed by broth microdilution according to the CLSI approved standard M38-A3 document.

Results: Seven species complexes (SC) with 17 Fusarium species were identified. The most prevalent SC was the F. solani SC (70.5%, 67/95), followed by the F. fujikuroi SC (16.8%, 16/95). F. keratoplasticum within the F. solani SC was the most prevalent species (32.6%, 31/95). There were 91.6% (87/95) of isolates identified by MALDI-TOF MS at the SC level. In most of species, amphotericin B and voriconazole showed lower MICs compared to itraconazole and terbinafine. The F. solani SC showed higher MICs to these antifungal agents compared to the other SCs. There were 10.5% (10/95) of strains with high MICs for amphotericin B (≥8 μg/ml), terbinafine (≥32 μg/ml) and itraconazole (≥32 μg/ml) simultaneously, mostly focusing on F. keratoplasticum (9/10).

Conclusion: MALDI-TOF MS exhibited good performance on the identification of Fusarium strains at the SC level. The F. solani SC was the most prevalent clinical SC in Southern China. The MICs varied significantly among different species or SCs to different antifungal agents.

Keywords: Fusarium; humans; mass spectrometry; microbial sensitivity tests; sequence analysis.