Fungal Colonization of the Airways of Patients with Cystic Fibrosis: the Role of the Environmental Reservoirs

Filamentous fungi frequently colonize the airways of patients with cystic fibrosis and may cause severe diseases, such as the allergic bronchopulmonary aspergillosis. The most common filamentous fungi capable to chronically colonize the respiratory tract of the patients are Aspergillus fumigatus and Scedosporium species. Defining the treatment strategy may be challenging, the number of available drugs being limited and some of the causative agents being multiresistant microorganisms. The knowledge of the fungal niches in the outdoor and indoor environment is needed for understanding the origin of the contamination of the patients. In light of the abundance of some of the causative molds in compost, agricultural and flower fields, occupational activities related to such environments should be discouraged for patients with cystic fibrosis (CF). In addition, the microbiological monitoring of their indoor environment, including analysis of air and dust on surfaces, is essential to propose preventive measures aiming to reduce the exposure to environmental molds. Nevertheless, some specific niches were also identified in the indoor environment, in relation with humidity which favors the growth of thermotolerant molds. Potted plants were reported as indoor reservoirs for Scedosporium species. Likewise, Exophiala dermatitidis may be spread in the kitchen via dishwashers. However, genotype studies are still required to establish the link between dishwashers and colonization of the airways of CF patients by this black yeast. Moreover, as nothing is known regarding the other filamentous fungi associated with CF, further studies should be conducted to identify other potential specific niches in the habitat.

Arthrographis kalrae Keratitis Complicated by Endophthalmitis: A Case Report With Literature Review

OBJECTIVES

To report the first case of Arthrographis kalrae keratitis complicated by endophthalmitis in the UK and to review the current literature.

METHODS

A case report with literature review.

RESULTS

A 65-year-old male patient, with a background of treated B-cell lymphoma and herpes simplex virus-related neurotrophic keratopathy, presented with a large infiltrative corneal ulcer in the right eye. The patient was immediately commenced on empirical antifungal treatment in view of the clinical suspicion of fungal keratitis (FK). The initial corneal scrape identified the organism as nonspecific "mold," and the identity of A. kalrae was subsequently confirmed using matrix-assisted laser/desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS). During the clinical course, the patient received topical, intrastromal, intracameral, and systemic antifungal treatment, repeat therapeutic corneal cross-linking treatment, and three penetrating keratoplasties. Although a temporary improvement was achieved with therapeutic corneal cross-linking treatment, the FK progressed relentlessly and was ultimately complicated by an endophthalmitis despite maximum medical and surgical treatment, eventuating in an enucleation.

CONCLUSIONS

A. kalrae keratitis is an exceptionally rare clinical entity that poses significant therapeutic challenges. MALDI-TOF-MS serves as a useful diagnostic technique in identifying this rare organism. Although the literature suggested that A. kalrae keratitis may sometimes be controlled with antifungal medical treatment alone, this approach was proven to be futile in our immunocompromised patient with pre-existing neurotrophic keratopathy, suggesting that early surgical intervention such as therapeutic keratoplasty may be required in these cases.

[Fungal keratitis associated with the use of contact lenses (clinical case)]

Currently, the number of keratomycoses and the interest of ophthalmologists to this type of keratitis have significantly increased due to the severity of the disease and non-satisfactory outcomes in some cases. According to published data, perforation of the cornea develops 6 times more often after keratomycosis than after keratitis of another etiology. The outcomes of keratoplasty in these patients are also not always satisfactory. The article presents a relatively rare clinical case of keratomycosis in a teenager caused by Arthrographis kalrae. The description of diseases caused by this microorganism is rarely found in literature. We have found only 4 cases describing keratomycosis caused by A. kalrae. The case presented here is associated with the use of contact lenses. The microorganism was identified from a container with contact lenses. Fungicidal drugs such as Anidulafungin, Voriconazole, as well as topical and systemical Amphotericin B were used in the treatment. The patient was discharged with a good functional result (best-corrected visual acuity of 0.7). This case indicates the possibility of a positive functional outcome in treating keratomycosis with present-day means.

First case of Arthrographis kalrae fungemia in a patient with cystic fibrosis

Arthrographis kalrae is a hyalin fungus. It is a saprophyte of the environment, mainly found in soil and compost. In recent years, cases of opportunistic infections attributed to this pathogen have been described. Our patient was a 19-year-old woman with cystic fibrosis. She presented a bacterial and fungal pulmonary colonization with Aspergillus fumigatus and Arthrographis. kalrae. After her lung transplantation, she developed an A. kalrae fungemia, treated with caspofungin 50 mg/day associated to liposomal amphotericin B i.v. 3 mg/kg/day. The patient died 8 months after her transplantation as the result of a bacterial septic shock.

Immunomodulation over the course of experimental Arthrographis kalrae infection in mice

Arthrographis kalrae is occasionally described as an opportunistic human pathogen. This study investigated the immune response to A. kalrae during murine experimental infection (7, 14, 28 and 56 days post infection). The fungal load was higher in the early phase and mice presented with neurological syndrome over the course of the infection. There was a gradual increase in the level of anti-A. kalrae IgG and increased levels of DTH at 14 days. There was decreased IFN-γ (14-56 days) and an increase in IL-4 (7 and 56 days). Decreased levels of cytokines (IFN-γ, IL-4, IL-10 and IL-17) were observed in the brain at 56 days p.i. The results suggest that the immune response during murine A. kalrae infection modulates to the pattern of Th2 response. This study shows for the first time the cytokines and cellular immunomodulation that occur in response to an experimental infection with A. kalrae in mice.

Arthrographis kalrae soluble antigens present hemolytic and cytotoxic activities

Arthrographis kalrae is a dimorphic, cosmopolitan and neurotropic fungus that has been described as a rare human pathogen. This study investigated the hemolytic and cytotoxic activities of A. kalrae cell-free antigens (CFAs). Total CFAs and their Sephadex chromatography fractions were tested on mouse erythrocytes for hemolysis and on the P3U1 cell line for cytotoxicity. Hemolytic and cytotoxic activities were detected in distinct molecular mass (MM) fractions. Additionally, antibodies against isogenic erythrocytes sensitized with CFAs (anti-E-CFAs) inhibited hemolysis but not cytotoxicity. Hemolysis was not affected by heating, and a higher reactivity was detected in the carbohydrate-rich fractions, which decreased after reduction by periodate treatment. The pioneering nature of this work is due to the demonstration of the cytotoxic activity in A. kalrae and the suggestion that this activity may be due to molecules distinct from the hemolytic factor, with the latter potentially being a component with a high MM.

A Severe Case of Arthrographis kalrae Keratomycosis

A 52-year-old man with diabetes developed a unilateral central corneal ulcer after accidental foreign body inoculation. He complained of pain and loss of visual acuity in the injured eye, which displayed redness and edema and eventually discharged pus. A corneal scraping from the left eye orbit revealed fungal elements, and cultures of the material grew a fungus. The isolate was identified as Arthrographis kalrae based on gross and microscopic morphologies. The patient received amphotericin B intravenously and itraconazole orally. The wound healed following surgical intervention, but the patient lost the use of his left eye.