Invasive infections with Purpureocillium lilacinum: clinical characteristics and outcome of 101 cases from FungiScope® and the literature

Abstract

Objectives: To provide a basis for clinical management decisions in Purpureocillium lilacinum infection.

Methods: Unpublished cases of invasive P. lilacinum infection from the FungiScope® registry and all cases reported in the literature were analysed.

Results: We identified 101 cases with invasive P. lilacinum infection. Main predisposing factors were haematological and oncological diseases in 31 cases (30.7%), steroid treatment in 27 cases (26.7%), solid organ transplant in 26 cases (25.7%), and diabetes mellitus in 19 cases (18.8%). The most prevalent infection sites were skin (n = 37/101, 36.6%) and lungs (n = 26/101, 25.7%). Dissemination occurred in 22 cases (21.8%). Pain and fever were the most frequent symptoms (n = 40/101, 39.6% and n = 34/101, 33.7%, respectively). Diagnosis was established by culture in 98 cases (97.0%). P. lilacinum caused breakthrough infection in 10 patients (9.9%). Clinical isolates were frequently resistant to amphotericin B, whereas posaconazole and voriconazole showed good in vitro activity. Susceptibility to echinocandins varied considerably. Systemic antifungal treatment was administered in 90 patients (89.1%). Frequently employed antifungals were voriconazole in 51 (56.7%) and itraconazole in 26 patients (28.9%). Amphotericin B treatment was significantly associated with high mortality rates (n = 13/33, 39.4%, P = <0.001). Overall mortality was 21.8% (n = 22/101) and death was attributed to P. lilacinum infection in 45.5% (n = 10/22).

Conclusions: P. lilacinum mainly presents as soft-tissue, pulmonary or disseminated infection in immunocompromised patients. Owing to intrinsic resistance, accurate species identification and susceptibility testing are vital. Outcome is better in patients treated with triazoles compared with amphotericin B formulations.

Figure 1.

Enrolment and study flow chart. *Three cases were reported both in FungiScope^® and the literature.^,,

Figure 2.

Countries where Purpureocillium lilacinum infections have been reported. Thirty-one cases were reported from the United States, thirteen from Spain, eight from India, five from Slovakia, four each from France, Japan, and Taiwan, three each from Canada and Germany, two each from Belgium, Iran, Malaysia, New Zealand, Portugal, Russia, Serbia, Switzerland, and United Kingdom, and one case each was reported from Australia, Chile, Italy, Jamaica, Kuwait, Libya, Mexico, and South Africa. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 3.

Macroscopic, microscopic and histopathological presentation of Purpureocillium lilacinum. (a and b) Malt extract agar plate incubated at 26°C showing white to lilac colonies of P. lilacinum after 5 days and 7 days of culture. (c and d) Lactophenol cotton blue staining. Typical phialides with a distinct neck bearing conidia. Conidia are ellipsoidal to fusiform with a smooth wall. Magnification: ×400 and ×1000. (e) Lactophenol cotton blue staining. P. lilacinum isolate showing elongated phialides producing chains of lemon-shaped conidia. Magnification ×600. (f) Histopathological examination (Grocott stain) reveals three different aspects of P. lilacinum growing within infected tissue: globose yeast-like structures (red arrowhead), septate hyphae (yellow arrowhead) and conidia that arise from the apical orifice of a phialide (blue arrowhead). Magnification ×600. Images (a–d) courtesy of Jörg Steinmann and images (e–f) courtesy of René Pelletier.