Susceptibility to antifungal agents and enzymatic activity of Candida haemulonii and Cutaneotrichosporon dermatis isolated from soft corals on the Brazilian reefs

Abstract

Candida is a common fungus with the capacity to cause infections in humans. However, most studies have concentrated on clinical isolates and little is known about the identity, ecology and drug resistance of free living species/strains. Here, we isolate eight strains of Candida haemulonii and four strains of Cutaneotrichosporon dermatis from three marine cnidarian zoanthids species (Palythoa caribaeorum, Palythoa variabilis and Zoanthus sociatus) collected from Brazilian coral reefs. Strains were identified by sequencing of the D1/D2 domain LSU rDNA and ITS region. We tested these environmental isolates for their capacity to grow in media with increasing concentration of NaCl, capacity to grow in different temperatures, enzymatic activity and antifungal susceptibility. For C. haemulonii, all strains strongly produced gelatinase, esterase and albuminase and were either able to express lipase, phospholipase and keratinase, but not express urease and DNase. The strains were able to grow at 37 °C, but not at 39 °C, and except for LMS 40, all of them could grow in a 10 % NaCl medium. All isolates were resistant to all antifungals tested, with exception for ketoconazole and tioconazole (MIC = 2 µg/mL). For C. dermatis, all strains could grow at 39 °C and could not express phospholipase, keratinase or gelatinase. However, all were capable of expressing urease, lipase and esterase. Three out of four strains could grow in a 10 % NaCl medium, but none grew in a 30 % NaCl medium. The strains showed high values of minimal inhibitory concentration. LMPV 90 was resistant to tioconazole, terbinafine, fluconazole and posaconazole, and LMS 38 was resistant to all antifungal agents tested. We discuss the characterization of C. haemulonii and C. dermatis as a possible emerging pathogen due to its animal-related enzymatic arsenal and antifungal resistance.

The Threat Called Candida haemulonii Species Complex in Rio de Janeiro State, Brazil: Focus on Antifungal Resistance and Virulence Attributes

“…Our results are in agreement with those reported in the literature for this fungal complex, with a commonly observed increased resistance to fluconazole [ 1 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ], itraconazole, voriconazole, posaconazole and amphotericin B [ 1 , 3 , 27 , 32 , 33 , 34 ]. In general, the C. haemulonii complex exhibits in vitro susceptibility to echinocandins [ 3 , 29 , 33 , 35 , 36 , 37 ], although there are reports of resistance to this antifungal class [ 1 , 38 ].…”

Draft Genome Assembly and Annotation for Cutaneotrichosporon dermatis NICC30027, an Oleaginous Yeast Capable of Simultaneous Glucose and Xylose Assimilation

“…Based on our tentative findings and literature support, we speculate that C. dermatis may achieve pathogenicity owing to its ability to produce enzymes that are damaging to human tissues, including urease, esterase, and lipase. While some studies have reported that certain C. dermatis isolates may be resistant to several common clinical antifungal agents including echinocandins and amphotericin B, we detected no evidence of antifungal resistance genes within the genome of strain NICC30027 [ 18 , 19 ]. As such, whether it is able to resist antifungal treatment warrants further study.…”

“…Due to its ability to manufacture several essential enzymes associated with human tissues, C. dermatis has been described as an opportunistic pathogen responsible for infections of the skin, blood, and nails [ 18 ]. In addition, C. dermatis has resistance to some antifungal agents such as echinocandins and fluconazole [ 19 ].…”

On the Origins of a Species: What Might Explain the Rise of Candida auris?

“…C. haemulonii First described in 1961 as Torulopsis haemulonii after having been isolated from the gut of the blue-striped grunt fish ( Haemulon sciurus ) near the U.S. Florida coast [41]. Other marine settings: Seawater near Portugal in 1962 [41] and India in 2011 [42]Soft coral ( Palythoa variabilis ) in Brazil in 2016 [43]Skin of a dolphin (species not reported) near Suriname [44]Second most common yeast from pool water of captive bottlenose dolphins ( Tursiops truncates ) in the U.S. state of Connecticut [45]Indian researchers applied C. haemulonii to giant tiger shrimp ( Penaeus monodon )—widely farmed in aquaculture—finding that its presence boosted an immunostimulatory molecule in the shrimp, conferring protection against a viral infection that causes economic losses from shrimp die-off [42]. It is unclear whether C. haemulonii has become used more broadly in aquaculture since publication of the study in 2011.…”