Begerowomyces aurantius sp. nov., a novel yeast isolated from koalas' habitat in a Japanese zoological park.

Koalas are iconic mammals indigenous to Australia. These rare animals and their habitats are occasionally associated with pathogenic fungi, including species of Cryptococcus, and consequently, monitoring the mycobiota of areas inhabited by koalas is of considerable importance. In this report, we describe a novel basidiomycetous yeast isolated from a site in Kanazawa Zoo, Japan, associated with captive koalas. Swab samples were collected from koala breeding environments, from which we isolated a novel unencapsulated yeast characterized by ovoid to ellipsoidal cells (3.2-4.9 × 3.5-5 µm). These cells were observed to undergo polar budding and grow as parent bud pairs, with an optimal growth temperature of 28°C. Colonies grown on yeast extract peptone dextrose agar at 28°C have a characteristic coral pink color. On the basis of physiological, morphological, and molecular characters, the new species was placed in the genus Begerowomyces, and the name Begerowomyces aurantius JCM33898T(LSEM1333T=CBS16241T) is proposed.

A Case of Topical Ofloxacin-Induced Otomycosis and Literature Review.

The prevalence of fungal otitis externa, or otomycosis, has been increasing in recent decades. Fungi may act as primary pathogens in this condition, or they may occur as secondary infections after prolonged ototopical treatment with antibiotics, which alters the flora of the external auditory canal (EAC) and enables overgrowth of its fungal inhabitants. We report here a case of otomycosis by Candida parapsilosis, Malassezia obtusa, and Malassezia furfur as a secondary infection following prolonged otic ofloxacin treatment. To the best of our knowledge, although isolation of C. parapsilosis and M. furfur from the EAC is not uncommon, the recovery of M. obtusa has not yet been reported. We also conducted a literature review of the searchable data on PubMed concerning the isolation of Malassezia species from the human EAC.

Effect of Silver Diamine Fluoride on Reducing Candida albicans Adhesion on Dentine.

BACKGROUND: Candida albicans is the most frequent pathogenic fungus in oral cavities. It adheres to dental tissues as part of dental plaques and contributes to caries formation. OBJECTIVES: To evaluate the effect of silver diamine fluoride (SDF) on reducing C. albicans adhesion on dentine surfaces. METHODS: Flat dentine surfaces were prepared from bovine dental disks, and samples were divided into three groups. The first and second groups were pretreated for 3 min with 299 mM or 2.99 M SDF, respectively, and the third group (control) did not undergo any SDF pretreatment. All samples were washed, inoculated with C. albicans suspension onto their dentine surface, incubated at 30 °C for 6 h, and washed again to remove any nonadherent cells. The abundance of adherent cells was investigated using colorimetric and real-time polymerase chain reaction approaches. Subsequently, the morphological changes in C. albicans by pretreatment with SDF were observed under a scanning electron microscope (SEM). RESULTS: SDF inhibited candidal growth at concentrations as low as 2.99 µM. Dentine disks pretreated with 299 mM or 2.99 M SDF displayed significantly fewer adhered cells as compared with the control group. Upon pretreatment with SDF, SEM images showed severe morphological changes in the cellular walls, in a dose-dependent manner, suggesting a fungicidal effect of SDF against the yeast. CONCLUSION: SDF should be considered for clinical applications aimed at inhibiting dental plaque caused by C. albicans, particularly in children and elderly individuals.

Cavity adaptation of composite restorations prepared at crown and root: Optical assessment using SS-OCT.

Evaluation of gap formation at the interfaces of a two-step self-etching adhesive with/without pre-etching was performed using sweptsource optical coherence tomography (SS-OCT). Round cavities were prepared in bovine incisors at the middle (MC) and cervical (CC) thirds of the crown and the cervical third of the root (CR). Clearfil SE bond was directly applied to one group (SE) and another (PA) was pretreated with K-etchant gel. Following restoration by flowable composite resin, the teeth were thermally challenged and stored for 2 months. Interfacial gaps observed in the cross-sectional OCT images were analyzed and the bottom cavities exhibited increased gaps compared to the margin and dentin-enamel junction (DEJ). The CR site had a larger gap than at MC and CC in the SE group. DEJ separation at the MC was significantly smaller than that at CC in both groups. Therefore, gap formation depends on the cavity region, location, and bonding protocol.