Purpureocillium lilacinum an emergent pathogen: antifungal susceptibility of environmental and clinical strains

Abstract

Purpureocillium lilacinum is a filamentous and hyaline fungus cosmopolitan, saprophytic, largely used in the biological control of plant‐parasitic nematodes and insects, also considered an emerging and opportunistic human pathogen. The standard treatment for hyalohyphomycosis caused by P. lilacinum is not yet defined, since this fungus is resistant to different antifungals, in vitro and in vivo. The aim of this study was to evaluate and compare in vitro antifungal activity against environmental and clinical P. lilacinum isolates and our results demonstrated that these isolates can be resistant to newer generation triazoles, such as voriconazole, and to caspofungin, a drug of the echinocandin class. In summary, we highlight the importance of knowing the different susceptibility profiles of P. lilacinum isolates, and besides that, the emergence of uncommon human and animal opportunistic fungi, such P. lilacinum, especially during COVID‐19, highlight the need for antifungal susceptibility testing of isolates since empirical therapy with different treatment schedules failed in great number of patients.

Lymphadenitis caused by Purpureocillium lilacinum in a patient with CARD9 deficiency

“…In our case, oral administration of VRCZ effectively reduced the size of swollen lymph nodes and lowered the biomarker levels. The low MIC of this isolate to VRCZ was consistent with the data of several reports showing that P. lilacinum clinical isolates have low MICs to VRCZ and posaconazole [ 4 , 15 ]. Although the breakpoint has yet to be established [ 4 , 15 ], ECMM and ISHAM recommend VRCZ as a first-line therapy in Global Guideline for the Diagnosis and Management of Rare Mold Infections [ 3 ].…”

Successful treatment of Purpureocillium lilacinum pulmonary infection with isavuconazole: A case report

“…There are only a few clinical cases of P. lilacinum , so no standard antifungal regimens exist[ 10 ]. Aguilar et al [ 11 ] showed early on that amphotericin B, miconazole, itraconazole, fluconazole, and flucytosine are less active against penicillium[ 11 ].…”

Cutaneous Hyalohyphomycosis and Its Atypical Clinical Presentations in Immunosuppressed Patients

“…In one experimental murine study, the subcutaneous inoculation of P. lilacinum caused comparable damage to animal tissue, including dermatitis, panniculitis, and skin ulcerations with a diffuse inflammatory infiltrate in both immunosuppressed and immunocompetent mice. However, the lesions in immunosuppressed mice were more severe, including extensive areas of ulcers covered with crust, dermatitis, and suppurative panniculitis, with more fungal structures observed on histological slides [18]. Ulcerations are the result of angioinvasion, in both humans and mice.…”

“…Histopathologically, many of these fungi tend to invade blood vessels and produce hemorrhagic necrosis and tissue infarction [6], clinically presented as ulcerative lesions (e.g., Purpureocillium lilacinum) or eschars (e.g., Fusarium spp.) [17,18]. Figure 1 summarizes the spectrum of cutaneous hyalohyphomycosis, and associates various forms of cutaneous infections with the most common causative agent according to the reported cases.…”

“…Both adventitious sporulation and the escape from the immune system could be responsible for the high rates of recurrent infections and the lack of a spontaneous resolution, as is often seen in P. lilacinum infections [40]. Although the immune response towards the fungus differs between immunocompetent and immunosuppressed individuals, P. lilacinum is capable of causing damage in both groups [18,43]. An experimental murine study showed that, despite not developing any clinical signs of infection, infected immunocompetent mice did have evident tissue damage, assessed using a histopathological analysis, which revealed conidia-like structures in the lung tissue of these mice [43].…”