Thyroid abscess due to Scedosporium apiospermum

Scedosporiosis and lomentosporiosis: modern perspectives on these difficult-to-treat rare mold infections

SUMMARYAlthough Scedosporium species and Lomentospora prolificans are uncommon causes of invasive fungal diseases (IFDs), these infections are associated with high mortality and are costly to treat with a limited armamentarium of antifungal drugs. In light of recent advances, including in the area of new antifungals, the present review provides a timely and updated overview of these IFDs, with a focus on the taxonomy, clinical epidemiology, pathogenesis and host immune response, disease manifestations, diagnosis, antifungal susceptibility, and treatment. An expansion of hosts at risk for these difficult-to-treat infections has emerged over the last two decades given the increased use of, and broader population treated with, immunomodulatory and targeted molecular agents as well as wider adoption of antifungal prophylaxis. Clinical presentations differ not only between genera but also across the different Scedosporium species. L. prolificans is intrinsically resistant to most currently available antifungal agents, and the prognosis of immunocompromised patients with lomentosporiosis is poor. Development of, and improved access to, diagnostic modalities for early detection of these rare mold infections is paramount for timely targeted antifungal therapy and surgery if indicated. New antifungal agents (e.g., olorofim, fosmanogepix) with novel mechanisms of action and less cross-resistance to existing classes, availability of formulations for oral administration, and fewer drug-drug interactions are now in late-stage clinical trials, and soon, could extend options to treat scedosporiosis/lomentosporiosis. Much work remains to increase our understanding of these infections, especially in the pediatric setting. Knowledge gaps for future research are highlighted in the review.

A Case of Invasive Fungal Infection Due to Scedosporium apiospermum in a Patient with Psoriasis

Scedosporium apiospermum (S. apiospermum) is typically reported to be involved in superficial and subcutaneous fungal infections but overlooked in invasive infections, which is associated with a high mortality rate. It poses a diagnostic challenge due to its confusable characteristics to other hyaline hyphomycetes. Here, we reported a psoriasis patient with an invasive S. apiospermum infection. The patient presents an abscess at the intermuscular space of the left hip and an increased C-reactive protein level. Pus culture showed white-greyish, cottonlike colonies with aerial mycelium and terminal oval conidia, suggesting S. apiospermum. This rare fungus was rapidly confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and RNA sequencing. The patient was successfully treated with voriconazole with no recurrence of the abscesses despite delayed treatment. This is the first such case infection report from China that described an unusual case of intermuscular space abscesses due to S. apiospermum. This report highlights the possibility of fungal infections in deeper tissue, as well as the necessity of thorough evaluation and microbiological diagnosis for invasive infections, particularly in immunocompromised patients.

A Repertoire of Clinical Non-Dermatophytes Moulds

Humans are constantly exposed to micromycetes, especially filamentous fungi that are ubiquitous in the environment. In the presence of risk factors, mostly related to an alteration of immunity, the non-dermatophyte fungi can then become opportunistic pathogens, causing superficial, deep or disseminated infections. With new molecular tools applied to medical mycology and revisions in taxonomy, the number of fungi described in humans is rising. Some rare species are emerging, and others more frequent are increasing. The aim of this review is to (i) inventory the filamentous fungi found in humans and (ii) provide details on the anatomical sites where they have been identified and the semiology of infections. Among the 239,890 fungi taxa and corresponding synonyms, if any, retrieved from the Mycobank and NCBI Taxonomy databases, we were able to identify 565 moulds in humans. These filamentous fungi were identified in one or more anatomical sites. From a clinical point of view, this review allows us to realize that some uncommon fungi isolated in non-sterile sites may be involved in invasive infections. It may present a first step in the understanding of the pathogenicity of filamentous fungi and the interpretation of the results obtained with the new molecular diagnostic tools.

Idiopathic thyroid abscess

INTRODUCTION

Thyroid abscesses are uncommon because the gland is relatively resistant to developing infection due to its rich blood supply, well-developed capsule and high iodine content. However, clinicians must be aware of this differential to make an early diagnosis.

PRESENTATION OF CASE

We present the case of a patient who required urgent operative resection as definitive treatment for a thyroid abscess secondary to infection with Staphylococcus aureus.

DISCUSSION

Although this is rare, a thyroid abscess left untreated can lead to serious morbidity. Therefore, clinicians must be aware of the presenting features and therapeutic options.

CONCLUSION

Thyroid abscess is an uncommon diagnosis but can lead to significant morbidity. Therefore clinicians must be aware of the diagnosis in order to institute early aggressive management.

Diabetic foot ulcer due to scedosporium apiospermum

We report a case of diabetic foot ulcer caused by Scedosporium apiospermum in a seventy year old male patient with uncontrolled diabetes. Scedosporium apiospermum, the asexual phase of Pseudallescheria boydii a fungus isolated from a variety of natural substrates throughout the world including soil, polluted water, sewage and manure of poultry and cattle. P.boydii is now recognized as a medically important opportunistic fungus. This case has been reported for its rarity.

The emerging epidemiology of mould infections in developing countries

PURPOSE OF REVIEW

The present review describes the emerging trends of mould infections in developing countries, and highlights the major epidemiological differences from the developed countries.

RECENT FINDINGS

The limited data available from developing countries suggest an alarming increase in invasive mould infections, especially aspergillosis and mucormycosis, and also a difference in risk factors and causative agents between the developed and developing world. Sino-orbital, cerebral and ophthalmic infections due to Aspergillus flavus are the major clinical types in aspergillosis, after pulmonary aspergillosis. Aspergillus and Fusarium spp. are frequent causes of trauma-associated keratitis in agricultural workers. Rhino-orbito-cerebral presentation associated with uncontrolled diabetes is the predominant mucormycosis. Isolated renal mucormycosis has emerged as a new clinical entity. Apophysomyces elegans and Mucor irregularis are emerging species in these regions and uncommon agents such as Rhizopus homothallicus have also been reported. Many pathogens are geographically restricted, with Pythium insidionum, Rhinocladiella mackenziei and M. irregularis being described almost exclusively from Thailand, Middle East and China, respectively.

SUMMARY

Despite limited studies, certain peculiarities have been observed in invasive mould infections in developing countries, including a high incidence of ophthalmic lesions, mucormycosis and aspergillosis; few different clinical presentations; and a varied spectrum of pathogens involved in such lesions.