Complete clinical response to combined antifungal therapy in two cats with invasive fungal rhinosinusitis caused by cryptic Aspergillus species in section Fumigati

Fungal Rhinosinusitis in Cats in the United Kingdom: 34 Cases (2013-2022)

BACKGROUND

Fungal rhinosinusitis in cats is an uncommon condition with sparse literature regarding the presentation, causative agents, diagnosis, treatment, and prognosis within the UK.

HYPOTHESIS/OBJECTIVES

To describe and report the presenting clinical signs, diagnostic imaging findings, treatment approach, and outcome of cats diagnosed with fungal rhinosinusitis in the UK.

ANIMALS

Thirty-four client-owned cats were diagnosed with fungal rhinosinusitis.

METHODS

Retrospective multicenter observational study. Cases presenting at 10 UK referral centers between January 2013 and December 2022 were retrospectively recruited.

RESULTS

Median duration of clinical signs was 3 months (0.5-42-months). The most common signs were sneezing (27/34, 79%) and nasal discharge (21/34, 62%). Turbinate lysis was present in 27/34 cases (79%) and always involved the caudal nasal cavity. Osteolysis of the frontal bone, orbit, or cribriform plate was observed in 16/34 cases (47%). At least two tests from fungal culture, panfungal PCR, and histopathology were performed in all cases, and in 8/34 cases (24%) only one was positive. The treatment approach varied, with debridement, topical clotrimazole, and systemic azole therapy used alone or in various combinations, and repeat treatment occurred in 9/34 cases (26%). Clinical remission > 90 days after treatment was found in 9/24 cases (38%), but case fatality rates were low, with 3/34 cases (9%) dying with clinical disease during available follow-up.

CONCLUSIONS AND CLINICAL IMPORTANCE

Fungal rhinosinusitis should be considered in cats of any age with clinical signs of nasal disease. The prognosis from this data appears guarded for cats with fungal rhinosinusitis, with less than 50% of cats achieving long-term clinical remission.

Azole resistance in Aspergillus isolates from animals or their direct environment (2013-2023): a systematic review

The resistance of Aspergillus species to azoles in human medicine is gaining increasing attention, and the role of animals and agricultural practices in this issue is becoming a significant source of concern. To gain better insights into the occurrence of azole resistance in Aspergillus spp. isolates from animals, a systematic literature review was conducted. Searches were conducted in the PubMed and Scopus databases for articles addressing azole resistance in Aspergillus spp. isolates from both animals and their immediate environments, published between 2013 and 2024. Descriptive clinical cases were analyzed separately from articles providing in-vitro susceptibility test results. MIC50 and MIC90 values, along with the number of non-wild type (NWT) isolates, were either directly extracted from the articles or calculated based on published results of individual isolates or MIC distributions. Ultimately, seventy-three out of 2042 articles were included in the analysis. Articles reporting clinical cases included only horses, dogs, cats, zoo animals, and wildlife, with the majority of cases occurring outside Europe. Generally, successful clinical remission or recovery followed prolonged and continuous fungicide azole treatments, regardless of the azole-Aspergillus spp.-animal category combination. Itraconazole was the most frequently noted treatment in clinical cases involving companion animals (dogs and cats) and horses. The weighted geometric mean of the MIC50 values for itraconazole was lowest for A. fumigatus isolates within the companion animal category. Zoo animals and wildlife were often treated with voriconazole, and the weighted geometric mean of the MIC50 values for this and other azoles was equal to or slightly lower than those calculated for A. fumigatus isolates from other animal categories. NWT A. fumigatus isolates were reported in zoo animals and wildlife, horses, companion animals, and poultry for several azoles, occurring both in Europe and beyond, in healthy and sick animals. In conclusion, zoo animals and wildlife, horses, and poultry represent a more significant concern regarding the prevalence of A. fumigatus and A. flavus NWT isolates than other animal categories. Insufficient data prevented conclusions about the situation specifically in Europe, and therefore, more systematic and comparable data are required.

Successful Treatment of Sino-Orbital Aspergillus udagawae Infection Using Oral Posaconazole in a Cat

A 10 yr old spayed female ragdoll cat presented with sudden onset of sneezing, nasal discharge, and stertor. There was no improvement in clinical signs despite treatment with antibiotics, feline interferon, and nebulization. A computed tomography (CT) scan revealed findings consistent with chronic rhinitis, and a tissue biopsy obtained by rhinoscopy led to a histopathologic diagnosis of sinonasal aspergillosis. Polymerase chain reaction amplification identified the causative agent as Aspergillus udagawae. Oral itraconazole therapy was initiated. However, the cat's clinical signs progressed to include left exophthalmos, nictitating membrane protrusion, and lacrimation. A second CT scan revealed a soft-tissue attenuating structure extending into the left retrobulbar space, confirming progression to sino-orbital aspergillosis (SOA). The oral medication was changed to posaconazole and continued for 5 mo, resulting in resolution of the clinical signs. The cat has remained asymptomatic over 24 mo since initial diagnosis. This case represents the first successful treatment of feline SOA caused by A udagawae infection with posaconazole. A udagawae is the second most common cause of SOA and is known to be intractable because of its low susceptibility to antifungal agents and poor response to topical clotrimazole. Posaconazole may be a valuable treatment option for SOA caused by A udagawae.

Invasive fungal infections and oomycoses in cats 2. Antifungal therapy

CLINICAL RELEVANCE

Invasive fungal infections (IFIs) and oomycoses (hereafter termed invasive fungal-like infections [IFLIs]) are characterised by penetration of tissues by fungal elements. The environment is the most common reservoir of infection. IFIs and IFLIs can be frustrating to treat because long treatment times are usually required and, even after attaining clinical cure, there may be a risk of relapse. Owner compliance with medication administration and recheck examinations can also decline over time. In addition, some antifungal drugs are expensive, have variable interpatient pharmacokinetic properties, can only be administered parenterally and/or have common adverse effects (AEs). Despite these limitations, treatment can be very rewarding, especially when an otherwise progressive and fatal disease is cured.

AIM

In the second of a two-part article series, the spectrum of activity, mechanisms of action, pharmacokinetic and pharmacodynamic properties, and AEs of antifungal drugs are reviewed, and the treatment and prognosis of specific IFIs/IFLIs - dermatophytic pseudomycetoma, cryptococcosis, sino-orbital aspergillosis, coccidioidomycosis, histoplasmosis, sporotrichosis, phaeohyphomycosis, mucormycosis and oomycosis - are discussed. Part 1 reviewed the diagnostic approach to IFIs and IFLIs.

EVIDENCE BASE

Information on antifungal drugs is drawn from pharmacokinetic studies in cats. Where such studies have not been performed, data from 'preclinical' animals (non-human studies) and human studies are reviewed. The review also draws on the wider published evidence and the authors' combined expertise in feline medicine, mycology, dermatology, clinical pathology and anatomical pathology.

ABBREVIATIONS FOR ANTIFUNGAL DRUGS

AMB (amphotericin B); FC (flucytosine); FCZ (fluconazole); ISA (isavuconazole); ITZ (itraconazole); KCZ (ketoconazole); PCZ (posaconazole); TRB (terbinafine); VCZ (voriconazole).

Clinical remission of feline sino-nasal aspergillosis despite evidence of persistent infection

Case summary

Feline sino-nasal aspergillosis is a rare condition with only sparse heterogeneous reports in the literature regarding its treatment. This report describes the presentation, treatment and outcome of a cat with sino-nasal aspergillosis treated by meticulous debridement in combination with topical and systemic azole therapy. Diagnosis was based on MRI, in combination with rhinoscopic assessment and visualisation of fungal plaques, followed by histopathology, fungal culture and panfungal PCR. The cat was treated by debridement of fungal plaques via anterior rhinoscopy and frontal sinusotomy and local instillation of 1% clotrimazole solution, followed by a 4-week course of oral itraconazole. Histopathology confirmed fungal rhinitis and culture identified Aspergillus fumigatus and Aspergillus versicolor. Clinical remission was achieved after treatment; however, evidence of persistent infection was confirmed in the post-mortem examination 8 months after the cat was euthanased for unrelated reasons.

Relevance and novel information

Despite clinical remission, the persistence of fungal infection post mortem highlights the challenges of monitoring the response to treatment and illustrates that the resolution of clinical signs does not necessarily equate with a disease cure.

Sino-orbital aspergillosis with obstructive cervical lymphadenopathy in a cat caused by Aspergillus viridinutans complex

Case summary

This report describes an indoor-only cat with a rare form of sino-orbital aspergillosis (SOA) with cervical lymphadenopathy causing local obstruction. Extensive work-up on initial presentation failed to identify the underlying etiology and the diagnosis was not determined until the disease progressed during a prolonged course of glucocorticoid therapy.

Relevance and novel information

SOA caused by Aspergillus viridinutans complex is increasingly recognized as a significant cause of mortality in cats in recent years, with most cases reported in Australia, Europe and Asia. Feline SOA carries a poor prognosis owing to its invasive nature and resistance to antifungal therapy. This case demonstrates the importance of clinical awareness of SOA as a differential for cats with chronic nasal signs and exophthalmos in the USA. Moreover, it demonstrates a rare form of presentation and potential difficulty in achieving a correct diagnosis.