Infection and colonisation due to Scedosporium in Northern Spain. An in vitro antifungal susceptibility and molecular epidemiology study of 60 isolates

Abstract

SummarySince the latest taxonomical changes in the genus Scedosporium by Gilgado et al. in 2010, no species-specific studies on epidemiology and antifungal susceptibility patterns (AFSP) have so far been published. This study aimed to provide qualitative epidemiological data of Scedosporium spp. isolated from cystic fibrosis (CF) patients and immunocompromised patients from Northern Spain. Isolates were identified by using amplified fragment length polymorphism (AFLP), and species-specific AFSP were generated for all currently available antifungal compounds. AFLP was a useful tool for identification to species-level and for the discrimination of inter-and intra-patient isolates. Scedosporium prolificans represents the most prevalent species in the respiratory tract of CF patients and immunocompromised patients in Northern-Spain, followed by Pseudallescheria boydii, P. apiosperma, and P. ellipsoidea. CF patients were exclusively colonised with either P. boydii or S. prolificans. Patients were colonised over years exclusively with isolates affiliated to one species, but some patients were colonised with multiple strains with different AFSP. The sum of those co-colonising strains in one patient, may appear in vitro and in vivo as a multi-resistant S. prolificans isolate, as strains are morphologically identical and might therefore be regarded as only one strain. A majority of Scedosporium strains (with exception of S. prolificans) were found susceptible for voriconazole and micafungin.

Susceptibility and Diversity in the Therapy-Refractory Genus Scedosporium

“…Kaltseis et al (28) noted that S. boydii is more frequently found in clinical specimens than S. apiospermum. This difference was not observed by Lackner et al (29). Bernhardt et al (30) noted that S. boydii had an incidence equal to or lower than that of S. apiospermum in pulmonary colonization of patients with cystic fibrosis.…”

Species-Specific Antifungal Susceptibility Patterns of Scedosporium and Pseudallescheria Species

“…They are the most prevalent Pseudallescheria species (43), but published studies of in vitro susceptibility profiles according to the latest taxonomical standards are rare (25). The two species have similar susceptibility profiles, with the lowest MICs/MECs of VRC and MICA.…”

“…AFLP. All isolates were identified down to species level based on the similarities of their amplified fragment length polymorphism (AFLP) profiles relative to those of the included type and reference strains (25). AFLP analysis was performed according to established procedures (8,25,38).…”

Epidemiology of Scedosporiosis

“…However, infections are also increasingly recognized in the Netherlands, UK, California, Southern USA, Korea, Germany and France [4, 7, 14, 22, 27, 28, 29••]. Of interest, many reports of clinical S. aurantiacum infection have been reported from Australia [5,18], the Netherlands [30], Spain [13] and Japan [31]. The major epidemiological features between the three main groups of pathogenic Scedosporium fungi are summarized in Table 1.…”

“…Since there are species-specific differences in the geographical distribution, host risk groups, organ-specific predilection and in vitro antifungal susceptibilities [7,[12][13][14][15], understanding the epidemiology of scedosporiosis is essential to This article is part of the Topical Collection on Epidemiology of Fungal Infections its management and prevention. The evolving taxonomy of these fungi continues to challenge species identification yet increasing use of molecular techniques has opened up insights into the epidemiology of Scedopsorium and scedosporiosis [16•, 17].…”