Molecular Epidemiology, Antifungal Susceptibility, and Virulence Evaluation of Candida Isolates Causing Invasive Infection in a Tertiary Care Teaching Hospital

Abstract

BackgroundThe incidence of invasive candidiasis is increasing worldwide. However, the epidemiology, antifungal susceptibility, and virulence of Candida spp. in most hospitals remain unclear. This study aimed to evaluate invasive candidiasis in a tertiary care hospital in Nanchang City, China.MethodsMALDI-TOF MS and 18S rDNA ITS sequencing were used to identify Candida strains. Randomly amplified polymorphic DNA analysis was used for molecular typing; biofilm production, caseinase, and hemolysin activities were used to evaluate virulence. The Sensititre™ YeastOne YO10 panel was used to examine antifungal susceptibility. Mutations in ERG11 and the hotspot regions of FKS1 of drug-resistant strains were sequenced to evaluate the possible mechanisms of antifungal resistance.ResultsWe obtained 110 Candida strains, which included 40 Candida albicans (36.36%), 37 C. parapsilosis (33.64%), 21 C. tropicalis (19.09%), 9 C. glabrata (8.18%), 2 C. rugose (1.82%), and 1 C. haemulonii (0.91%) isolates. At a limiting point of 0.80, C. albicans isolates could be grouped into five clusters, C. parapsilosis and C. tropicalis isolates into seven clusters, and C. glabrata isolates into only one cluster comprising six strains by RAPD typing. Antifungal susceptibility testing revealed that the isolates showed the greatest overall resistance against fluconazole (6.36%), followed by voriconazole (4.55%). All C. albicans and C. parapsilosis isolates exhibited 100% susceptibility to echinocandins (i.e., anidulafungin, caspofungin, and micafungin), whereas one C. glabrata strain was resistant to echinocandins. The most common amino acid substitutions noted in our study was 132aa (Y132H, Y132F) in the azole-resistant strains. No missense mutation was identified in the hotpot regions of FKS1. Comparison of the selected virulence factors detectable in a laboratory environment, such as biofilm, caseinase, and hemolysin production, revealed that most Candida isolates were caseinase and hemolysin producers with a strong activity (Pz < 0.69). Furthermore, C. parapsilosis had greater total biofilm biomass (average Abs620 = 0.712) than C. albicans (average Abs620 = 0.214, p < 0.01) or C. tropicalis (average Abs620 = 0.450, p < 0.05), although all C. glabrata strains were either low- or no-biofilm producers. The virulence level of the isolates from different specimen sources or clusters showed no obvious correlation. Interesting, 75% of the C. albicans from cluster F demonstrated azole resistance, whereas two azole-resistant C. tropicalis strains belonged to the cluster Y.ConclusionThis study provides vital information regarding the epidemiology, pathogenicity, and antifungal susceptibility of Candida spp. in patients admitted to Nanchang City Hospital.

WMR Peptide as Antifungal and Antibiofilm against Albicans and Non-Albicans Candida Species: Shreds of Evidence on the Mechanism of Action

“…A deeper investigation on the mechanisms of action of WMR on C. albicans and C. parapsilosis was performed. C. parapsilosis is among the most pathogenic NAC species in clinics [26]. In fact, the increasing incidence of C. parapsilosis candidemia is related to long-term hospitalization, affinity to the surface of intravascular devices, prosthetic materials or plastics to form biofilms, and also high glucose and fat environments favoring gastrointestinal colonization and transmission [27,28].…”

Distribution and antifungal susceptibility pattern ofCandidaspecies from mainland China: A systematic analysis

“…However, Beijing is political, and Shanghai is the economic hub of China, and people from all around the country are directly or indirectly connected with these two cities. There is also a chance of bias due to the not mentioned patient type in numerous studies; usually, the Candida species isolated from inpatients are less susceptible than outpatient [ 65 , 125 ]. In addition, it would be preferable to include studies that contain at least 30 isolates to ensure high-quality data accuracy [ 66 , 126 ].…”

Multilocus Sequence Typing and Antifungal Susceptibility of Vaginal and Non-vaginal Candida glabrata Isolates From China

“…Fungal infections caused by C. glabrata , especially those associated with resistance to fluconazole, have resulted in a global health problem ( Chen et al, 2021 ; Darwish et al, 2021 ; Rodrigues et al, 2021 ). Investigating the prevalence of C. glabrata molecular genotypes is important for preventing local epidemic spreading.…”