Bipolaris oryzae, a novel fungal opportunist causing keratitis

Morphological and phylogenetic analyses of Bipolaris species associated with Poales and Asparagales host plants in Iran

Bipolaris species exhibit various ecological roles, including plant pathogens, epiphytes, saprophytes, or endophytes, primarily associated with poaceous hosts, including cultivated cereals. Iran is known for its diverse climates and rich flora, which serve as a hotspot for fungal diversity. In this study, to determine the species diversity of Bipolaris associated with members of the Poales and Asparagales plant orders, samples with leaf and stem lesion symptoms were collected from these plants across various locations in Iran between 2010 and 2022. Based on the morphological characteristics and multi-locus phylogeny (ITS-rDNA, GAPDH, and TEF1), nine Bipolaris species were identified: Bipolaris avrinica sp. nov., Bipolaris azarbaijanica sp. nov., Bipolaris banihashemii sp. nov., Bipolaris hedjaroudei sp. nov., Bipolaris hemerocallidis sp. nov., Bipolaris iranica sp. nov., Bipolaris persica sp. nov., Bipolaris crotonis, and Bipolaris salkadehensis. B. crotonis represents a new record for Iran's funga, while B. salkadehensis has been documented on several new hosts globally. The study provides detailed morphological descriptions and illustrations of all identified species, along with insights into their habitats, distributions, and phylogenetic relationships within the Bipolaris genus. This study also emphasizes the need for further research into fungal biodiversity in Iran and provides significant data on the distribution and host range of Bipolaris species.

Phaeohyphomycosis in China

Background

Due to more attentions paid to melanized fungi over the past few decades and under the background of the global coronavirus disease 2019 pandemic (COVID-19) the fact that the virus itself and the immunosuppressive agents such as glucocorticoids can further increase the risk of infections of deep mycoses, the number of patients with phaeohyphomycosis (PHM) has a substantial increase. Their spectrum is broad and the early diagnosis and treatments are extremely sticky. This study aims to more comprehensively understand the clinical features of phaeohyphomycosis in China over 35 years and to establish a more applicable systematical classification and severity grades of lesions to guide treatments and prognosis.

Methods

We reviewed 174 cases of proven phaeohyphomycosis reported in Chinese and English language literature from 1987 to 2021 and we also made the accurate classification definitions and detailed information about the epidemiology, species of clinical dematiaceous fungi, minimum inhibitory concentration values, clinical features, treatments, and prognosis.

Results

The mortality of cerebral, disseminated and pulmonary phaeohyphomycosis are 55%, 36%, and 25%. Nearly 19% of patients had poor quality of life caused by the complications such as disability, disfigurements, and blindness. The overall misdiagnosis rate of phaeohyphomycosis was 74%. Moderate to severe rashes are accounting for 82% of subcutaneous phaeohyphomycosis. The areas of the head and face are mostly affected accounting for 16% of severe rashes. Nearly 30% of invasive infections of phaeohyphomycosis are triggered by recurrent lesions. Voriconazole, itraconazole, amphotericin B deoxycholate (AmB-DOC), and terbinafine were most commonly used but diagnosis and treatments of phaeohyphomycosis remain challenging in reality.

Conclusions

Our classifications are likely to be more practical and easier to popularize, and there are still also plenty of characteristics in these non-specific lesions. There’re no significant variations in cure rates, or death rates between three grades of lesions. But patients with severe rashes have longer courses and lower effective rates.

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.

The Spectrum of Microbial Keratitis: An Updated Review

Background:

In microbial keratitis, infection of the cornea can threaten vision through permanent corneal scarring and even perforation resulting in the loss of the eye. A literature review was conducted by Karsten, Watson and Foster (2012) to determine the spectrum of microbial keratitis. Since this publication, there have been over 2600 articles published investigating the causative pathogens of microbial keratitis.

Objective:

To determine the current spectrum of possible pathogens implicated in microbial keratitis relative to the 2012 study.

Methods:

An exhaustive literature review was conducted of all the peer-reviewed articles reporting on microbial pathogens implicated in keratitis. Databases including MEDLINE, EMBASE, Scopus and Web of Science were searched utilising their entire year limits (1950-2019).

Results:

Six-hundred and eighty-eight species representing 271 genera from 145 families were implicated in microbial keratitis. Fungal pathogens, though less frequent than bacteria, demonstrated the greatest diversity with 393 species from 169 genera that were found to cause microbial keratitis. There were 254 species of bacteria from 82 genera, 27 species of amoeba from 11 genera, and 14 species of virus from 9 genera, which were also identified as pathogens of microbial keratitis.

Conclusion:

The spectrum of pathogens implicated in microbial keratitis is extremely diverse. Bacteria were most commonly encountered and in comparison, to the review published in 2012, further 456 pathogens have been identified as causative pathogens of microbial keratitis. Therefore, the current review provides an important update on the potential spectrum of microbes, to assist clinicians in the diagnosis and treatment of microbial keratitis.

Corneal ulcer due to a rare pleosporalean member of the genus following cow tail injury to the eye: A case report and review of literature

Aspergillus and Fusarium are the most common fungi causing mycotic keratitis. Injury to the eye with vegetable matter, cow tail injury, long-term use of topical steroids are some of the risk factors for mycotic keratitis. There are few case reports of keratitis caused by Bipolaris. The human pathogenic species in the genus are Bipolaris spicifera, Bipolaris hawaiiensis, Bipolaris papendorfii, and Bipolaris australiensis. Most commonly reported keratitis is caused by B. hawaiiensis, followed by B. spicifera. Literature review showed only one case report of keratitis due to B. australiensis reported from Australia. We present a first case report of keratitis due to B. australiensis (currently Curvularia australienis) from India.

PCR methodology and applications for the detection of human fungal pathogens

INTRODUCTION

Polymerase chain reaction (PCR) has emerged as a promising technology for the rapid and reliable detection and identification of medical mycoses. Recent technological advancements - including microarray, multiplex PCR with magnetic resonance, and beacon probes - have mitigated the technical difficulties of performing nucleic amplification in fungi, thereby improving the sensitivity and specificity of PCR-based assays. In this paper, we examine current applications of PCR in the diagnosis of human fungal infections and look ahead to emerging techniques that may play a larger role in molecular diagnostics in the future.

AREAS COVERED

This review includes a brief overview of the advantages and disadvantages of PCR using various clinical specimens, manual versus automated DNA extraction procedures, panfungal versus specific targets, and spectrum of pathogens detected. This is followed by a brief synopsis of species-specific PCR approaches and a more in-depth look at the obstacles to widespread implementation. Expert commentary: The review concludes with a short perspective for the next five years, including the hurdles to standardization and validation, as well as the role of PCR coupled with electrospray-ionization mass spectrometry (PCR/ESI-MS) or nuclear magnetic resonance for the diagnosis of medical mycoses.