In vitro characterization and molecular epidemiology of Cryptococcus spp. isolates from non-HIV patients in Guangdong, China

Penglei Wang; Yongming Li; Lei Gao; Xiang Tang; Dandian Zheng; Kuihai Wu; Luxia Wang; Penghao Guo; Feng Ye

doi:10.3389/fmicb.2023.1295363

In vitro characterization and molecular epidemiology of Cryptococcus spp. isolates from non-HIV patients in Guangdong, China

Front Microbiol. 2024 Jan 15:14:1295363. doi: 10.3389/fmicb.2023.1295363. eCollection 2023.

Authors

Penglei Wang^#^{1

2}, Yongming Li^#¹, Lei Gao³, Xiang Tang⁴, Dandian Zheng⁵, Kuihai Wu⁶, Luxia Wang⁷, Penghao Guo⁸, Feng Ye¹

Affiliations

¹ State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, National Center for Respiratory Medicine, Guangzhou, China.
² Department of Respiratory Medicine, Longgang Central Hospital, Shenzhen, China.
³ Microscopy Core Facility, Biomedical Research Core Facilities, Westlake University, Hangzhou, China.
⁴ Intensive Care Unit, Guangzhou First People's Hospital, Guangzhou, China.
⁵ Department of Hematology Oncology, Jieyang City People's Hospital, Jieyang, China.
⁶ Clinical Medicine Laboratory, Foshan City First People's Hospital, Foshan, China.
⁷ Clinical Medicine Laboratory, Southern Military Region General Hospital, Guangzhou, China.
⁸ Clinical Medicine Laboratory, Sun Yat-sen University First Affiliated Hospital, Guangzhou, China.

^# Contributed equally.

Abstract

Background: The burden of cryptococcosis in mainland China is enormous. However, the in vitro characterization and molecular epidemiology in Guangdong, a key region with a high incidence of fungal infection in China, are not clear.

Methods: From January 1, 2010, to March 31, 2019, clinical strains of Cryptococcus were collected from six medical centres in Guangdong. The clinical information and characteristics of the strains were analysed. Furthermore, molecular types were determined.

Results: A total of 84 strains were collected, mostly from male and young or middle-aged adult patients. Pulmonary and cerebral infections (82.1%) were most common. All strains were Cryptococcus neoformans, grew well at 37°C and had capsules around their cells. One melanin- and urea- and one melanin+ and urea- variants were found. Although most strains exhibited a low minimum inhibitory concentration (MIC) value for voriconazole (mean: 0.04 μg/mL) and posaconazole (mean: 0.12 μg/mL), the results for these isolates showed a high degree of variation in the MIC values of fluconazole and 5-fluorocytosine, and resistance was observed for 4 out of 6 drugs. A significant proportion of these strains had MIC values near the ECV values, particularly in the case of amphotericin B. The proportion of strains near the clinical breakpoints was as follows: fluconazole: 3.66%; voriconazole: 3.66%; itraconazole: 6.10%; posaconazole: 13.41%; amphotericin B: 84.15%; 5-fluorocytosine: 2.44%. These strains were highly homogeneous and were dominated by the Grubii variant (95.2%), VNI (94.0%), α mating (100%), and ST5 (89.3%) genotypes. Other rare types, including ST4, 31, 278, 7, 57 and 106, were also found.

Conclusion: Phenotypically variant and non-wild-type strains were found in Guangdong, and a significant proportion of these strains had MIC values near the ECV values towards the 6 antifungal drugs, and resistance was observed for 4 out of 6 drugs. The molecular type was highly homogeneous but compositionally diverse, with rare types found. Enhanced surveillance of the aetiology and evolution and continuous monitoring of antifungal susceptibility are needed to provide references for decision-making in the health sector and optimization of disease prevention and control.

Keywords: Cryptococcus; antifungal susceptibility test; genetic evolution analysis; molecular epidemiology; virulence factor.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by the Natural Science Foundation of Guangdong Province (2022A1515010089) and the Open Fund of the State Key Laboratory of Respiratory Diseases (SKLRD-OP-202210).