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

Background: 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 identification, and investigate the epidemiology and antifungal susceptibility profiles of clinical isolates in Southern China.

Methods: There were 95 clinical 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 species were identified. The most prevalent SC was the SC (70.5%, 67/95), followed by the SC (16.8%, 16/95). within the 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 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 (9/10).

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