Ochroconis humicola coexisting with esthesioneuroblastoma: an incidental coloniser or allergen?

Cladosporium halotolerans: Exploring an Unheeded Human Pathogen

BACKGROUND

Cladosporium halotolerans is a saprobic fungus, rarely implicated in human infections. The identification is challenging due to non-specific phenotypic features.

OBJECTIVE

To decipher clinical spectrum, microbiological and susceptibility profile of clinical and environmental isolates of Cladosporium halotolerans.

METHOD

All the isolates identified as Cladosporium halotolerans deposited in National Culture Collection for Pathogenic Fungi (NCCPF), Postgraduate Institute of Medical Education and Research, Chandigarh, India were revived. Phenotypic and molecular characterization targeting internal transcribed spacer (ITS) region of ribosomal DNA, large subunit of ribosomal DNA (LSU; NL1 and NL4), actin (ACT) and beta-tubulin (TUB) was done. Scanning electron microscopy (SEM) was performed to determine any phenotypic variations. Antifungal susceptibility testing (AFST) was carried out for eight antifungal agents as per CLSI M38 Ed3 guidelines. We also performed systematic literature review of all the cases of Cladosporium halotolerans reported till date.

RESULTS

A total of four isolates (clinical, n = 3; soil, n = 1) identified as Cladosporium halotolerans were included in the study. The clinical sites were skin, maxillary tissue and nail. All patients were apparently immunocompetent, and history of trauma was recorded in one patient. All patients improved on antifungal therapy. The cultures revealed growth of black mycelial fungus and microscopic examination demonstrated dematiaceous septate hyphae with erect conidiophores and conidia in branched acropetal chains. Based on molecular methods, all the four isolates were identified as C. halotolerans. SEM revealed no variation in length and width of the conidia, conidiophores, ramoconidium and hyphae among the isolates. All molecular targets, such as ITS region, LSU (partially sequenced), ACT and TUB were able to differentiate the isolates. Minimum inhibitory concentrations for antifungals were: triazoles (0.12-2 μg/ml), amphotericin B (4 μg/ml) and echinocandins (2-8 μg/ml).

CONCLUSION

We report role of the rarely isolated dematiaceous fungus, C. halotolerans, in causing human infections. The study emphasizes the role of molecular methods in precisely identifying these species. Triazoles are more active against these black fungi compared to polyenes or echinocandins.

Ocular infection caused by Hormographiella aspergillata: A case report and review of literature

Hormographiella aspergillata, a basidiomycete is a rare cause of human infection. We report a case of 70-year-old female with corneal ulcer and endophthalmitis caused by this agent. The patient had an intraocular implantation of lens following a cataract surgery. Corneal tissue obtained during therapeutic penetrating keratoplasty showed presence of septate hyphae on microscopy and culture grew H. aspergillata which was confirmed by sequencing of ITS region. Patient was started on systemic voriconazole and topical natamycin, however the eye could not be salvaged. To our knowledge, this is the first report of ocular infection caused Hormographiella aspergillata in an immunocompetent patient.

Indoor wet cells as a habitat for melanized fungi, opportunistic pathogens on humans and other vertebrates

Indoor wet cells serve as an environmental reservoir for a wide diversity of melanized fungi. A total of 313 melanized fungi were isolated at five locations in Guangzhou, China. Internal transcribed spacer (rDNA ITS) sequencing showed a preponderance of 27 species belonging to 10 genera; 64.22% (n = 201) were known as human opportunists in the orders Chaetothyriales and Venturiales, potentially causing cutaneous and sometimes deep infections. Knufia epidermidis was the most frequently encountered species in bathrooms (n = 26), while in kitchens Ochroconis musae (n = 14), Phialophora oxyspora (n = 12) and P. europaea (n = 10) were prevalent. Since the majority of species isolated are common agents of cutaneous infections and are rarely encountered in the natural environment, it is hypothesized that indoor facilities explain the previously enigmatic sources of infection by these organisms.