Colletotrichum truncatum: an unusual pathogen causing mycotic keratitis and endophthalmitis

Clinical spectrum, phenotypic and molecular characterization, and antifungal susceptibility of an emerging human pathogen, Acrophialophora, from India

Acrophialophora is implicated in superficial and invasive infections, especially in immunosuppressed individuals. The present study was undertaken to provide clinical, microbiological, phylogenetic, and antifungal susceptibility testing (AFST) profile of Acrophialophora isolated from India. All the isolates identified as Acrophialophora species at the National Culture Collection for Pathogenic Fungi, Chandigarh, India were revived. Phenotypic and molecular characterization was performed, followed by temperature studies, scanning electron microscopy (SEM), and AFST. We also performed systematic review of all the cases of Acrophialophora species reported till date. A total of nine isolates identified as Acrophialophora species were identified by molecular method as A. fusispora (n = 8) and A. levis (n = 1), from brain abscess (n = 4), respiratory tract (n = 3), and corneal scraping (n = 2). All patients but two had predisposing factors/co-morbidities. Acrophialophora was identified as mere colonizer in one. Temperature studies and SEM divulged variation between both species. Sequencing of the internal transcribed spacer ribosomal DNA and beta-tubulin loci could distinguish species, while the LSU ribosomal DNA locus could not. AFST showed the lowest minimum inhibitory concentrations (MICs) for triazoles and the highest for echinocandins. Systematic literature review revealed 16 cases (11 studies), with ocular infections, pulmonary and central nervous system infections, and A. fusispora was common species. All the patients except three responded well. High MICs were noted for fluconazole, micafungin, and caspofungin. This is the first study delineating clinical, phenotypic, and genotypic characteristics of Acrophialophora species from India. The study highlights microscopic differences between both species and emphasizes the role of molecular methods in precise identification. Triazoles appear to be the most effective antifungals for managing patients.

Identification and Characterization of Colletotrichum truncatum and C. destructivum Causing Stem Rot of White Clover in China

White clover (Trifolium repens L.) is an excellent quality forage legume species with superior planting efficiency, which reduces the cost of artificial weeding and nitrogen fertilizer inputs, and has feeding and economic value. However, from June to September 2022, severe stem rot affected the yield and quality of white clover crops in Harbin, Heilongjiang Province, China. The aim of this study was to identify the causative agents of the disease. Overall, Colletotrichum truncatum (6 isolates) and C. destructivum (10 isolates) were obtained from rotten white clover stems and identified based on morpho-molecular characteristics and phylogenetic analyses. Pathogenicity tests of the isolates revealed that C. destructivum had a higher pathogenicity to white clover than C. truncatum. In addition, all isolates were highly pathogenic to broad bean, fodder soybean, soybean, pak choi, and chickpea, were pathogenic to mint, and did not infect corn, wheat, or cilantro. C. destructivum and C. truncatum isolates were very sensitive to tebuconazole and pyraclostrobin, with EC50 values of 0.54 to 0.70 μg/ml and 0.42 to 0.62 μg/ml, respectively, efficacies ranging between 93.2 to 94.9% and 90.2 to 95.2% at 600 μg/ml and 450 μg/ml, respectively, and EC90 values of 1.88 to 13.36 μg/ml and 1.32 to 23.39 μg/ml, respectively. Therefore, intercropping of host and nonhost plants and chemicals can be considered to control stem rot in white clover. These results provide a basis for controlling C. destructivum and C. truncatum in white clover in China.

Consensus and controversies in the science of endophthalmitis management: Basic research and clinical perspectives

Infectious endophthalmitis is a severe intraocular infection caused by bacteria, or less commonly by fungi. It can occur after penetrating eye procedures, trauma, or the spread of infection from contiguous structures or via emboli from distant organs. Because of the time-critical nature of the treatment, endophthalmitis is treated with the clinical diagnosis and modified by the microbiological report of the intraocular contents. The current strategy for managing endophthalmitis relies on pre-clinical literature, case series, and one large multi-center randomized clinical trial on post-cataract surgery endophthalmitis. Culture-susceptibility of the microorganisms from undiluted vitreous guides the definitive treatment in non-responsive cases. Strategies to reduce the incidence of endophthalmitis after penetrating eye procedures have been developed concurrently with refined means of treatment. Despite these advances, outcomes remain poor for many patients. Although consensus articles have been published on managing endophthalmitis, treatment patterns vary, and controversies remain. These include (1) the use of newer methods for early and precise microbiological diagnosis; (2) the choice of intravitreal antibiotics; (3) the need for systemic therapy; (4) early and complete vitrectomy. Here, we review the current consensus and address controversies in diagnosing and managing endophthalmitis. This review is intended to familiarize physicians and ophthalmologists with different aspects of endophthalmitis management to make informed decisions.

Clinical and Mycologic Characteristics of Emerging Mucormycosis Agent Rhizopus homothallicus

We retrospectively reviewed consecutive cases of mucormycosis reported from a tertiary-care center in India to determine the clinical and mycologic characteristics of emerging Rhizopus homothallicus fungus. The objectives were ascertaining the proportion of R. homothallicus infection and the 30-day mortality rate in rhino-orbital mucormycosis attributable to R. homothallicus compared with R. arrhizus. R. homothallicus accounted for 43 (6.8%) of the 631 cases of mucormycosis. R. homothallicus infection was independently associated with better survival (odds ratio [OR] 0.08 [95% CI 0.02-0.36]; p = 0.001) than for R. arrhizus infection (4/41 [9.8%] vs. 104/266 [39.1%]) after adjusting for age, intracranial involvement, and surgery. We also performed antifungal-susceptibility testing, which indicated a low range of MICs for R. homothallicus against the commonly used antifungals (amphotericin B [0.03-16], itraconazole [0.03-16], posaconazole [0.03-8], and isavuconazole [0.03-16]). 18S gene sequencing and amplified length polymorphism analysis revealed distinct clustering of R. homothallicus.

New seed coating containing Trichoderma viride with anti-pathogenic properties

Background

To ensure food security in the face of climate change and the growing world population, multi-pronged measures should be taken. One promising approach uses plant growth-promoting fungi (PGPF), such as Trichoderma, to reduce the usage of agrochemicals and increase plant yield, stress tolerance, and nutritional value. However, large-scale applications of PGPF have been hampered by several constraints, and, consequently, usage on a large scale is still limited. Seed coating, a process that consists of covering seeds with low quantities of exogenous materials, is gaining attention as an efficient and feasible delivery system for PGPF.

Methods

We have designed a new seed coating composed of chitin, methylcellulose, and Trichoderma viride spores and assessed its effect on canola (Brassica napus L.) growth and development. For this purpose, we analyzed the antifungal activity of T. viride against common canola pathogenic fungi (Botrytis cinerea, Fusarium culmorum, and Colletotrichum sp.). Moreover, the effect of seed coating on germination ratio and seedling growth was evaluated. To verify the effect of seed coating on plant metabolism, we determined superoxide dismutase (SOD) activity and expression of the stress-related RSH (RelA/SpoT homologs).

Results

Our results showed that the T. viride strains used for seed coating significantly restricted the growth of all three pathogens, especially F. culmorum, for which the growth was inhibited by over 40%. Additionally, the new seed coating did not negatively affect the ability of the seeds to complete germination, increased seedling growth, and did not induce the plant stress response. To summarize, we have successfully developed a cost-effective and environmentally responsible seed coating, which will also be easy to exploit on an industrial scale.

Anthracnose Controlled by Essential Oils: Are Nanoemulsion-Based Films and Coatings a Viable and Efficient Technology for Tropical Fruit Preservation?

Post-harvest diseases can be a huge problem for the tropical fruit sector. These fruits are generally consumed in natura; thus, their integrity and appearance directly affect commercialization and consumer desire. Anthracnose is caused by fungi of the genus Colletotrichum and affects tropical fruits, resulting in lesions that impair their appearance and consumption. Antifungals generally used to treat anthracnose can be harmful to human health, as well as to the environment. Therefore, essential oils (EO) have been investigated as natural biofungicides, successfully controlling anthracnose symptoms. The hydrophobicity, high volatility, and oxidative instability of essential oils limit their direct application; hence, these oils must be stabilized before food application. Distinct delivery systems have already been proposed to protect/stabilize EOs, and nanotechnology has recently reshaped the food application limits of EOs. This review presents robust data regarding nanotechnology application and EO antifungal properties, providing new perspectives to further improve the results already achieved in the treatment of anthracnose. Additionally, it evaluates the current scenario involving the application of EO directly or incorporated in films and coatings for anthracnose treatment in tropical fruits, which is of great importance, especially for those fruits intended for exportation that may have a prolonged shelf life.

Colletotrichum asianum: A Novel Phytopathogen Causing Human Infection-A Case Report

PURPOSE

The purpose of this study was to report the predisposing factors, clinical features, microbiological characteristics, and the management of the novel identified species, Colletotrichum asianum .

METHODS

Two patients, farmers by occupation, with a history of trauma with vegetative material, presented to us with redness and pain. The corneal scrapings revealed branched hyphae on potassium hydroxide mount, and woolly aerial fungal mycelia with gray colonies were seen on blood agar and potato dextrose agar. The findings were suggestive of a novel fungal organism C. asianum .

RESULTS

Both patients showed a remarkable response to commonly used antifungal agents. A healing response was obtained in 4 weeks. Molecular analysis by sequencing of the internal transcribed region of ribosomal DNA was performed to confirm the species C. asianum in both cases.

CONCLUSIONS

To the best of our knowledge, this is the first case report describing infective keratitis secondary to C. asianum .

Publicly Available and Validated DNA Reference Sequences Are Critical to Fungal Identification and Global Plant Protection Efforts: A Use-Case in Colletotrichum

Publicly available and validated DNA reference sequences useful for phylogeny estimation and identification of fungal pathogens are an increasingly important resource in the efforts of plant protection organizations to facilitate safe international trade of agricultural commodities. Colletotrichum species are among the most frequently encountered and regulated plant pathogens at U.S. ports-of-entry. The RefSeq Targeted Loci (RTL) project at NCBI (BioProject no. PRJNA177353) contains a database of curated fungal internal transcribed spacer (ITS) sequences that interact extensively with NCBI Taxonomy, resulting in verified name-strain-sequence type associations for >12,000 species. We present a publicly available dataset of verified and curated name-type strain-sequence associations for all available Colletotrichum species. This includes an updated GenBank Taxonomy for 238 species associated with up to 11 protein coding loci and an updated RTL ITS dataset for 226 species. We demonstrate that several marker loci are well suited for phylogenetic inference and identification. We improve understanding of phylogenetic relationships among verified species, verify or improve phylogenetic circumscriptions of 14 species complexes, and reveal that determining relationships among these major clades will require additional data. We present detailed comparisons between phylogenetic and similarity-based approaches to species identification, revealing complex patterns among single marker loci that often lead to misidentification when based on single-locus similarity approaches. We also demonstrate that species-level identification is elusive for a subset of samples regardless of analytical approach, which may be explained by novel species diversity in our dataset and incomplete lineage sorting and lack of accumulated synapomorphies at these loci.

Therapeutic Penetrating Keratoplasty in a Case of Corneal Perforation Caused by Colletotrichum gloeosporioides Infection

Background: Corneal infection of Colletotrichum gloeosporioides is uncommon and usually limited to the anterior stroma. However, we observed a case of corneal stromal perforation caused by this fungus under a compromised condition. Case: A 73-year-old woman consulted us with a severe corneal ulceration. She was a tangerine orange farmer who suffered from rheumatoid arthritis for more than ten years. Before consultation with us, she received pterygium excision in her right eye. She then developed a corneal ulceration and received topical glucocorticoid therapy upon diagnosis of rheumatoid arthritis-related stromal ulcer in the eye. At the first consultation with us, a corneal ulceration was observed in the inferotemporal area of her right cornea. Biological examination detected a filamentous fungus, Colletotrichum gloeosporioides. Topical and systemic antifungal treatments were not significantly effective. Fourteen days after consultation, the lesion grew worse, leading to stromal perforation, which was treated by therapeutic penetrating keratoplasty using a preserved corneal button. Conclusions: Topical glucocorticoid could accelerate the growth of Colletotrichum gloeosporioides before diagnosis, even though the primary cause of corneal ulceration development might be rheumatoid arthritis.

Clinical Spectrum, Molecular Characterization, Antifungal Susceptibility Testing of Exophiala spp. From India and Description of a Novel Exophiala Species, E. arunalokei sp. nov

Introduction

Exophiala spp. are important opportunist pathogens causing subcutaneous or even fatal disseminated infections in otherwise both immunosuppressed and healthy individuals but there are no systematic studies on the isolates of Exophiala species from India.

Methods

Twenty-four isolates of Exophiala species were retrieved from the National Culture Collection of Pathogenic Fungi (NCCPF) and identified phenotypically and by molecular methods (ITS region sequencing) followed by antifungal susceptibility testing (AFST) as per CLSI-M38A3 guidelines. A review of the literature of cases from India was performed up to 1^st January 2021 using the Medline and Cochrane database.

Results

E. dermatitidis (n = 8), E. jeanselmei (n = 6), E. spinifera (n = 6), E. mesophila (n = 1), E. oligosperma (n = 1), E. xenobiotica (n = 1) were identified and the sequencing of ITS, β-tubulin and β-actin revealed a novel species, E. arunalokei sp. nov. (n = 1). The ITS sequence phylogram of E. jeanselmei revealed that the majority (83%) formed a separate cluster close to type A while majority (75%) of E. dermatitidis were type B. The MIC50 (mg/L) of amphotericin, itraconazole, voriconazole, micafungin, caspofungin, anidulafungin, and posaconazole, was 1, 0.25, 0.125, 0.12, 0.125, 0.062, and 0.062, respectively. Sixteen more cases were identified on the literature review and a significant association of E. dermatitidis with history of surgical procedures (p = 0.013), invasive disease (p = 0.032) and of E. mesophila with tuberculosis (p = 0.026) was seen.

Conclusion

This, to the best of our knowledge is the first study from India elucidating the molecular and clinical characteristics of Exophiala species and the first Indian report of human infection due to E. xenobiotica and E. arunalokei.

Recent advances on mycotic keratitis caused by dematiaceous hyphomycetes

Dematiaceous hyphomycetes (DH) are darkly pigmented fungi ubiquitously found all over the world as plant pathogens and saprophytes, and many of the members of this group have emerged as opportunistic pathogens. These fungi are responsible for a wide variety of infections including mycotic keratitis, which is considered as one of the major causes of corneal blindness, particularly in tropical and subtropical countries with an annual global burden of about 1 000 000 patients. The infection is more common in workers working in an outdoor environment. Moreover, trauma is found to be the most important predisposing cause of mycotic keratitis. Considerable delay in diagnosis and scarcity of effective pharmacological drugs are the major factors responsible for increased morbidity and visual impairment. Considering the crucial role of DH in mycotic keratitis, in the present review, we have focused on major DH with special emphasis on their pathogenicity, diagnosis and treatment strategies.

Periconia species - An unusual fungal pathogen causing mycotic keratitis

PURPOSE

The purpose of this study is to determine the epidemiology, risk factors, clinical features, and treatment outcome of molecularly diagnosed Periconia keratitis.

METHODS

Clinical records of all culture proven fungal ulcers with molecular identification suggestive of Periconia species who presented to a single tertiary referral center from January 2012 to December 2013 were retrospectively analysed.

RESULTS

Among 1356 cases of keratomycosis, 8 (0.6%) patients were affected due to Periconia species. The mean age of presentation was 59 years with males (n = 6; 75%) were more commonly affected than females (n = 2; 25%). Significant history of trauma was present only in one patient. The infiltrate size was less than 5 mm in majority of patients 75% (n = 6). 50% (n = 4) responded to antifungal, 12.5% (n = 1) responded to antibacterial, 12.5% (n = 1) required therapeutic penetrating keratoplasty, 25% (n = 2) lost to follow up after first visit. The mean duration of treatment in healed cases was 20 days.

CONCLUSION

This is the first report on Periconia sp causing human corneal ulcer. This study signifies the importance of molecular identification in the diagnosis of rare fungi which will improve our understanding on disease pathology and outcome. Visual prognosis appears good if the infection is diagnosed and topical antifungal interventions started early.

Filamentous Fungal Keratitis in Taiwan: Based on Molecular Diagnosis

Purpose

To analyze the epidemiological pattern, demographics, risk factors, and treatment outcomes of filamentous fungal keratitis at a tertiary hospital in Taiwan.

Methods

We recruited 65 patients (65 eyes) with culture-proven filamentous fungal keratitis who received diagnosis and treatment at Chang Gung Memorial Hospital between 2015 and 2018. All isolates were examined through conventional morphological identification and subjected to molecular identification with internal transcribed spacer sequencing. Data on patient demographics, predisposing factors, and treatment outcomes were collected.

Results

In total, filamentous fungi belonged to 16 genera were identified. Fusarium spp. (29 cases [44.6%]) was the most commonly isolated organism overall, followed by Colletotrichum spp. and Purpureocillium linacinum (seven cases [10.8% for each]), and Aspergillus spp. (six cases [9.2%]). Some fungi that have not been regarded as human pathogens were also identified, such as Paracremonium and Phellinum. Among 52 (80%) patients with predisposing factors, 30 (46.2%) had trauma. The ulcers of 33 (50.8%) patients resolved with medical treatment only. Additionally, six patients (9.2%) had corneal perforation, and nine patients (13.9%) required therapeutic/destructive surgical interventions including therapeutic penetrating keratoplasty (seven patients) or evisceration (two patients). Only 16 patients (24.6%) had final visual acuity of 20/40 or better.

Conclusions

Through molecular diagnosis, a high diversity of fungal pathogens was revealed along with an increasing incidence of Colletotrichumspp. and Purpureocilliumspp. in Taiwan. The most common risk factor for filamentous fungal keratitis was trauma. The visual outcomes were guarded.

Translational Relevance

The molecular diagnosis provides insight into accurate identification, which affects the epidemiology and diversity of pathogens of filamentous fungal keratitis.

A rare case of Colletotrichum truncatum keratitis in a young boy with complete healing after medical treatment

Colletotrichum is a rare fungal pathogen, which is known to cause anthracnose in plants and keratitis or subcutaneous infections in humans. Among the seven Colletotrichum species reported in eye infections, truncatum species is usually virulent with poor visual prognosis even after surgical treatment. Here we report a case of Colletotrichum truncatum keratitis in a young boy with thorn injury that completely resolved with topical natamycin and voriconazole.

Crossing the kingdom border: Human diseases caused by plant pathogens

Interactions between pathogenic microorganisms and their hosts are varied and complex, encompassing open-field scale interactions to interactions at the molecular level. The capacity of plant pathogenic bacteria and fungi to cause diseases in human and animal systems was, until recently, considered of minor importance. However, recent evidence suggests that animal and human infections caused by plant pathogenic fungi, bacteria and viruses may have critical impacts on human and animal health and safety. This review analyses previous research on plant pathogens as causal factors of animal illness. In addition, a case study involving disruption of type III effector-mediated phagocytosis in a human cell line upon infection with an opportunistic phytopathogen, Pseudomonas syringae pv. tomato, is discussed. Further knowledge regarding the molecular interactions between plant pathogens and human and animal hosts is needed to understand the extent of disease incidence and determine mechanisms for disease prevention.

Colletotrichum keratitis: A rare yet important fungal infection of human eyes

BACKGROUND

Colletotrichum is a rare cause of human infection. Previous reports about Colletotrichum keratitis were limited, and most diagnoses from past reports were based on morphological distinction, which could have led to underestimation of the prevalence of Colletotrichum species.

OBJECTIVE

We reported phylogenetic analysis, clinical feature and treatment outcome of molecularly diagnosed Colletotrichum keratitis in our hospital.

PATIENTS/METHODS

We recruited 65 patients with culture-proven filamentous fungal keratitis between January 1, 2015 and December 30, 2018. Through molecular sequencing including internal transcribed spacer (ITS) and multi-locus phylogenetic analysis of fungal DNA, seven patients were verified as infected with Colletotrichum species, and their medical records were reviewed to determine the clinical characteristics.

RESULTS

Six of seven patients had predisposing factors including trauma (5) and immunosuppressive status (1). Six isolates were initially misidentified as other fungi through morphological identification. ITS sequencing identified the isolates belonged to two species complex (SC): C. truncatum and C. gloeosporioides; multi-locus phylogenetic analysis enabled species identification including C. tropicale (3), C. fructicola (2), C. truncatum (1) and C. fusiforme (1). Five patients with C. gloeosporioides SC responded well to medical treatment and two patients with C truncatum SC underwent evisceration because of either no visual potential or intractable pain.

CONCLUSIONS

The molecular approach provides accurate diagnosis and raises epidemiological awareness of Colletotrichum keratitis. Through multi-locus phylogenetic analysis, we report the human infections caused by C. tropicale, C. fructicola and C. fusiforme. We also highlight the different clinical outcomes between C. gloeosporioides SC and C. truncatum SC.

Colletotrichum: species complexes, lifestyle, and peculiarities of some sources of genetic variability

The genus Colletotrichum comprises species with different lifestyles but is mainly known for phytopathogenic species that infect crops of agronomic relevance causing considerable losses. The fungi of the genus Colletotrichum are distributed in species complexes and within each complex some species have particularities regarding their lifestyle. The most commonly found and described lifestyles in Colletotrichum are endophytic and hemibiotrophic phytopathogenic. Several of these phytopathogenic species show wide genetic variability, which makes long-term maintenance of resistance in plants difficult. Different mechanisms may play an important role in the emergence of genetic variants but are not yet fully understood in this genus. These mechanisms include heterokaryosis, a parasexual cycle, sexual cycle, transposable element activity, and repeat-induced point mutations. This review provides an overview of the genus Colletotrichum, the species complexes described so far and the most common lifestyles in the genus, with a special emphasis on the mechanisms that may be responsible, at least in part, for the emergence of new genotypes under field conditions.

Infectious Keratitis Caused by Rare and Emerging Micro-Organisms

PURPOSE

To provide a comprehensive review of rare and emerging micro-organisms causing infectious keratitis.

MATERIAL AND METHODS

A literature search was performed using PubMed Medline, Cochrane Library Database, EMBASE and Scopus (1960 onwards), using the terms: keratitis caused by rare pathogens; mycotic keratitis; fungal keratitis; bacterial keratitis; infectious keratitis; infective keratitis; atypical fungal keratitis; fungal keratitis caused by rare organisms; fungal keratitis caused by rare ocular pathogen; atypical bacterial keratitis; bacterial keratitis caused by rare organisms; bacterial keratitis caused by rare ocular pathogen. All relevant articles were included in this review.

RESULTS

A total of 1232 articles matched our search strategy of which 124 articles were included in this mini-review. The rare and emerging bacteria causing keratitis include atypical mycobacteria, Nocardia spp., Chrysebacterium spp., Delftia acidovorans, Kocuria spp., Enterococcus spp., Bartonella henslae, Achromobacter spp. and others. The rare and emerging fungi causing keratitis include Pythium spp., Alternaria spp., Acremonium spp., Cladosporium spp., Curvularia spp., Bipolaris spp., Microsporidia spp., Pseudallescheria spp., Colletotrichum spp., and others. The clinical presentation of these cases is variable. While a few organisms produce characteristic clinical features, rest present similar to bacterial or fungal keratitis with variable response to routine treatment. A strong degree of suspicion is therefore essential for its diagnosis. Special investigations like polymerase chain reaction, gene sequencing, mass spectroscopy and enzyme-linked immunosorbent assay are required for accurate identification of these organisms. Culture-sensitivity is extremely useful as drug resistance to routinely used anti-microbial drugs is common. Prognosis is usually poor for keratitis with Pythium spp., Pseudallescheria spp., Arthrographis spp., Purpureocillium spp., Kociria spp. and Achromobacter spp.

CONCLUSION

Keratitis caused by rare and emerging micro-organisms must be suspected in cases where the infection runs an unusual course or shows a poor response to standard anti-microbial drugs. Early diagnosis and timely treatment hold the key for a good outcome.

Parathyridaria percutanea and Subcutaneous Phaeohyphomycosis

Parathyridaria percutanea is an emerging fungus causing subcutaneous phaeohyphomycoses in renal transplant recipients in India. We identified P. percutanea from a patient with subcutaneous phaeohyphomycosis. From our culture collection, we identified the same fungus from 4 similar patients. We found 5 cases previously described in literature.

Facial Phaeohyphomycosis in an Immunocompetent Individual: A Rare Presentation of a Rare Fungus

Phaeohyphomycosis is a rare mycotic infection caused by heterogenous groups of dematiaceous fungi involving the skin and subcutaneous tissue. Here, we report a case of cutaneous phaeohyphomycosis presenting as cauliflower-like verrucous lesion over the face in an immunocompetent individual. Histopathology showed suppurative granulomatous inflammation replete with pigmented broad fungal hyphae which is stained with periodic acid-Schiff stain, Grocott's methanamine silver stain, Schmorl's stain, and Masson-Fontana stain. Culture showed black-colored colonies identified as Exophiala spinifera.

Fungal keratitis caused by rare organisms

Purpose

To report two rare cases of filamentous fungal keratitis.

Methods

Two non-consecutive patients presented with suspicious fungal keratitis. After performing the smear and culture, medical therapy was started for them. They underwent slit photography and in vivo confocal microscopy (IVCM) in their follow-up visits.

Results

The patients were 33-year-old and 56-year-old farmer men. They both mentioned a history of ocular trauma by plants. During their follow-up visits, corneal infiltration density and fungal hyphae density decreased in slit-lamp biomicroscopy and IVCM, respectively. The corresponding organisms were Pseudallescheria boydii (P. boydii) and Colletotrichum coccodes.

Conclusions

It is important to be aware of these rare organisms and their antibiotic susceptibility. There was not any specific confocal feature for the presented fungal keratitis that was different from other filamentous fungal hyphae; however, confocal scan is a good choice to follow the response to the treatment.

Coelomycetous Fungi in the Clinical Setting: Morphological Convergence and Cryptic Diversity

Human infections by coelomycetous fungi are becoming more frequent and range from superficial to systemic dissemination. Traumatic implantation of contaminated plant material is the most common cause. The typical morphological feature of these fungi is the production of asexual spores (conidia) within fruiting bodies called conidiomata. This study aimed to determine the distribution of the coelomycetes in clinical samples by a phenotypic and molecular study of a large set of isolates received from a U.S. reference mycological institution and by obtaining the in vitro antifungal susceptibility pattern of nine antifungals against a selected group of isolates. A total of 230 isolates were identified by sequencing the D1 and D2 domains of the large subunit (LSU) nuclear ribosomal RNA (nrRNA) gene and by morphological characterization. Eleven orders of the phylum Ascomycota were identified: Pleosporales (the largest group; 66.1%), Botryosphaeriales (19.57%), Glomerellales (4.35%), Diaporthales (3.48%), Xylariales (2.17%), Hysteriales and Valsariales (0.87%), and Capnodiales, Helotiales, Hypocreales and Magnaporthales (0.43% each). The most prevalent species were Neoscytalidium dimidiatum, Paraconiothyrium spp., Phoma herbarum, Didymella heteroderae, and Epicoccum sorghinum The most common anatomical site of isolation was superficial tissue (66.5%), followed by the respiratory tract (17.4%). Most of the isolates tested were susceptible to the majority of antifungals, and only flucytosine showed poor antifungal activity.

Non-traumatic keratitis due to Colletotrichum truncatum

INTRODUCTION

The fungal genus Colletotrichum is an uncommon cause of human infections. It has been implicated in cutaneous phaeohyphomycosis, artritis and keratitis secondary to traumatic implantation.

CASE PRESENTATION

We report two cases of keratitis due Colletotrichum truncatum in middle-aged, immunocompetent persons without history of trauma. The aetiological agents were identified based on DNA sequencing. Azoles and echinocandins showed high minimal inhibitory concentrations while amphotericin B was ≤ 0.25  mg l^-1. Both patients failed topical antifungal treatment and needed penetrating keratoplasty with a favourable outcome.

CONCLUSION

C. truncatum caused keratomycosis which did not respond to topical antifungal agents. To the best of our knowledge these are the first reported cases of keratitis due to this fungus in Cuba and Latin-America and highlights the expanding spectrum of fungal agents causing eye infections.

Subcutaneous Colletotrichum truncatum Infection in a Child

Human infection with Colletotrichum species is typically limited to ophthalmologic manifestations. We present the first reported pediatric case of subcutaneous Colletotrichum truncatum infection. This case highlights the potential importance of C. truncatum as an agent of subcutaneous or disseminated disease in immunocompromised children.

Treatment resistant fungal keratitis caused by Colletotrichum gloeosporioides

CASE REPORT

A 56 year old woman suffered corneal injury from a branch of an orange tree. Forty days later she suffered a severe ocular infection, positive to Colletotrichum gloeosporioides (C. gloeosporioides). The patient did not respond to traditional treatment or crosslinking, and had to be treated with keratoplasty, suffering intraoperative and postoperative complications.

DISCUSSION

Ocular infections due to C. gloeosporioides can occasionally be refractory to traditional and new treatments, such as crosslinking.

Colletotrichum truncatum species complex: Treatment considerations and review of the literature for an unusual pathogen causing fungal keratitis and endophthalmitis

We present a case of Colletotrichum truncatum species complex fungal keratitis and endophthalmitis in an 87-year-old immunocompetent male in whom oral triazole antifungals were contraindicated. The patient had recently returned from 4 months in Jamaica with a one month history of progressively increasing pain and inflammation in his left eye. Corneal samples grew a filamentous fungus and internal transcribed spacer sequencing polymerase chain reaction confirmed the presence of C. truncatum species complex. Samples showed no microbial growth.

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Colletotrichum species infections in humans are rare.

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We present a case of Colletotrichum truncatum species complex keratitis and endophthalmitis.

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Oral triazole was contraindicated due to concurrent tamsulosin use.

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A multidisciplinary approach is essential for timely diagnosis and tailoring of treatment.

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Further study needed to determine optimal management of Colletotrichum infections.

First Probable Case of Subcutaneous Infection Due to Truncatella angustata: a New Fungal Pathogen of Humans?

Truncatella angustata is a coelomycetous fungus, typically associated with vascular plants as either an endophyte or a pathogen. This organism has not previously been implicated in human disease. This report describes a case of T. angustata subcutaneous infection in an immunocompetent patient. A conclusive diagnosis was achieved through partial sequencing of ribosomal DNA (rDNA) cluster. The patient was successfully treated with voriconazole followed by itraconazole.

Pulmonary Gangrene Due to Rhizopus spp., Staphylococcus aureus, Klebsiella pneumoniae and Probable Sarcina Organisms

Pulmonary gangrene is a life-threatening condition, which represents the fulminant end of the infectious lung diseases usually caused by polymicrobial infection. Aerobic and anaerobic bacteria act synergistically to produce massive tissue necrosis which might be augmented by the angioinvasive nature of fungi like Mucor. We report a successfully treated case of pulmonary gangrene in a poorly controlled diabetic patient, which was associated with polymicrobial infection. It was caused by Rhizopus spp., Staphylococcus aureus, Klebsiella pneumoniae and unusual anaerobic organism Sarcina. This is the first report describing the presence of Sarcina organisms in a case of pulmonary gangrene. Adequate glycemic control, treatment of coexisting polymicrobial infection and prompt antifungal therapy along with surgical intervention were useful in the index patient. This case also highlights the effectiveness of combined medical and surgical intervention in a case of pulmonary gangrene.

Non traumatic keratitis due to colletotrichum coccodes: a case report

Colletotrichum species, a rare and emerging fungus is a well- known plant pathogen and an uncommon cause of human infection. It has been implicated as the etiological agent of cutaneous phaeohyphomycosis and keratitis, particularly following colonization of traumatized tissues or in immunocompromised patients. However, it has hardly ever been reported in the absence of such predisposing risk factors. Here, we report a case of keratitis with Colletotrichum coccodes occurring in a middle- aged, immunocompetent person without any history of trauma or co-morbidity. The isolate was sensitive to Amphotericin B and Voriconazole, and accordingly the patient was treated successfully with ocular administration of Amphotericin B.

Filamentous fungal infections of the cornea: a global overview of epidemiology and drug sensitivity

Fungal keratitis is a serious suppurative, usually ulcerative corneal infection which may result in blindness or reduced vision. Epidemiological studies indicate that the occurrence of fungal keratitis is higher in warm, humid regions with agricultural economy. The most frequent filamentous fungal genera among the causal agents are Fusarium, Aspergillus and Curvularia. A more successful therapy of fungal keratitis relies on precise identification of the pathogen to the species level using molecular tools. As the sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster (rDNA) is not discriminative enough to reveal a species-level diagnosis for several filamentous fungal species highly relevant in keratitis infections, analysis of other loci is also required for an exact diagnosis. Molecular identifications may also reveal the involvement of fungal species which were not previously reported from corneal infections. The routinely applied chemotherapy of fungal keratitis is based on the topical and systemic administration of polyenes and azole compounds. Antifungal susceptibility testing of the causal agents is of special importance due to the emergence and spread of resistance. Testing the applicability of further available antifungals and screening for new, potential compounds for the therapy of fungal keratitis are of highlighted interest.

Genetic differentiation and recombination among geographic populations of the fungal pathogen Colletotrichum truncatum from chili peppers in China

Colletotrichum truncatum is an extremely important fungal pathogen. It can cause diseases both in humans and in over 460 plant species. However, little is known about its genetic diversity within and among populations. One of the major plant hosts of C. truncatum is pepper, and China is one of the main pepper-producing countries in the world. Here, we propose the hypotheses that geography has a major influence on the relationships among populations of C. truncatum in China and that infections in different populations need to be managed differently. To test these hypotheses, we obtained and analyzed 266 C. truncatum isolates from 13 regions representing the main pepper-growing areas throughout China. The analysis based on nine microsatellite markers identified high intrapopulation genetic diversity, evidence of sexual recombination, and geographic differentiation. The genetic differentiation was positively correlated with geographic distance, with the southern and northern China populations grouped in two distinct clusters. Interestingly, isolates collected from the pepper-breeding center harbored the most private alleles. The results suggest that the geographic populations of C. truncatum on peppers in China are genetically differentiated and should be managed accordingly. Our study also provides a solid foundation from which to further explore the global genetic epidemiology of C. truncatum in both plants and humans.

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

Ochroconis humicola, a fish pathogen, is rarely reported to cause disease in human. We report its first isolation from nasal tissue of a human immunodeficiency virus-positive young female patient. Histopathologically, the nasal mass was diagnosed as esthesioneuroblastoma. She presented with right-sided nasal obstruction and bleeding for two and half months. Computed tomography scan showed the nasal mass filling the whole right nasal cavity, maxillary, ethmoid and sphenoid sinuses. The direct microscopy of the nasal tissue and mucin demonstrated the presence of septate hyphae. On culture, O. humicola was isolated from the same tissue and the fungus was identified by morphologic, physiologic and molecular data including sequencing of ITS and 28S rDNA regions. No antifungal was prescribed, and the whole mass was resected out by endoscopic surgery. The patient was treated further by radical radiotherapy. After 1 year of follow-up, patient is stable with no recurrence of tumour. The role of this fungus was not clear, as it may be bystander or producing allergic fungal rhinosinusitis.

Primary cutaneous mucormycosis presenting as a giant plaque: uncommon presentation of a rare mycosis

Mucormycosis is an uncommon systemic mycosis affecting the immunocompromised individuals. It is usually caused by organisms of the genera Rhizopus and Mucor, although rarely other organisms have also been implicated. Mycoses due to these angioinvasive fungi have an acute onset, rapidly progressive course with high mortality rate. A rare and less well known is the chronic subtype of primary cutaneous mucormycosis (PCM). Herein, we report a case of PCM clinically presenting as a chronic, giant destructive plaque in a young immunocompetent male and coin the term chronic granulomatous mucormycosis. A clinicopathological classification for cutaneous mucormycosis is also proposed.

[Fungal keratitis caused by Colletotrichum spp. A presentation of case]

CASE REPORT

A 23 years old male with an unremarkable past medical history suffered an injury with a branch of a lemon tree in the right eye two days prior to presentation. The slit-lamp examination showed a central corneal erosion with a white tree-shaped stromal infiltrate and Tyndall +/++ in anterior chamber. Cultivation of corneal scraping was positive for Colletotrichum spp. The patient responded favourably to topical amphotericin.

DISCUSSION

Colletotrichum spp. is an uncommon cause of keratitis, usually secondary to corneal erosion caused by plant material and should be included in the differential diagnosis of fungal keratitis.

PCR for the molecular diagnosis of mycotic keratitis

Mycotic keratitis, an infection of the cornea caused by fungi, is a medical emergency, with patients presenting with considerable pain and distress. For effective management of the condition, a specific diagnosis must be made rapidly to permit early initiation of antifungal therapy. Currently, direct microscopic examination and culture of corneal material constitute the 'gold standard' for diagnosis. However, rapid, sensitive yet specific tests are needed to detect a small number of, or nonviable, fungi. PCR has many potential advantages when used as a diagnostic aid for mycotic keratitis; the present review covers these advantages, and possible limitations. An expert assessment is also made of studies that have used PCR for the diagnosis of mycotic keratitis. The review concludes with a Five-year view of the potential impact of PCR in management of mycotic keratitis.

Colletotrichum - current status and future directions

A review is provided of the current state of understanding of Colletotrichum systematics, focusing on species-level data and the major clades. The taxonomic placement of the genus is discussed, and the evolution of our approach to species concepts and anamorph-teleomorph relationships is described. The application of multilocus technologies to phylogenetic analysis of Colletotrichum is reviewed, and selection of potential genes/loci for barcoding purposes is discussed. Host specificity and its relation to speciation and taxonomy is briefly addressed. A short review is presented of the current status of classification of the species clusters that are currently without comprehensive multilocus analyses, emphasising the orbiculare and destructivum aggregates. The future for Colletotrichum biology will be reliant on consensus classification and robust identification tools. In support of these goals, a Subcommission on Colletotrichum has been formed under the auspices of the International Commission on Taxonomy of Fungi, which will administer a carefully curated barcode database for sequence-based identification of species within the BioloMICS web environment.

Chronic disfiguring facial lesions in an immunocompetent patient due to Exophiala spinifera: a case report and review of literature

Exophiala spinifera is a rare fungus causing chromoblastomycosis or different types of phaeohyphomycosis (cutaneous, subcutaneous, disseminated and cyst phaeohyphomycosis). We report a case of a young male with phaeohyphomycosis due to E. spinifera, who had multiple itchy painful papular lesions disfiguring his face for 4 years. His diagnosis was delayed and had received antibacterial and antileishmanial therapy elsewhere without any improvement. While he reported to our hospital, the histopathology of the biopsy collected from the lesion demonstrated acute on chronic inflammation with granuloma formation and darkly pigmented fungal elements. The isolate grown on culture was identified as E. spinifera on the basis of morphological characters. The identification of the isolate was further confirmed by sequencing of the ITS region of ribosomal DNA. After treatment with oral itraconazole, he had marked clinical improvement.