, 1990; Itin et al., 1998). This species can contaminate antiseptic creams and (skin) lotions, sodium bicarbonate solutions used as a neutralizing agent for a sodium hydroxide sterilizer for artificial lenses, Staurosporine nmr and colonize materials such as catheters and plastic implants (Pettit et al., 1980; Orth et al., 1996; Itin et al., 1998). A 3-year surveillance study showed that Purpureocillium lilacinum was frequently found in water distribution system of a bone marrow transplantation unit. Purpureocillium lilacinum positive sites included water from water tanks and showers, sinks, showers (including drains), toilets and air. This species can thrive on wet and moist surfaces

of water distribution

systems and form a biofilm, together with other species such as Aspergillus, Fusarium and Acremonium (Anaissie et al., 2003). Although biofilm formation by filamentous fungi has been poorly studied, it is postulated that adhesion, colonization and matrix formation are key criteria in the biofilm formation process (Martinez & Fries, 2010). The capacity of Purpureocillium lilacinum to adhere to the waxy host cuticle of nematodes and its ability to colonize surfaces under harsh conditions with low nutrient concentrations (fungal biofilters, plastics) and low oxygen levels (Mountfort buy MK-2206 & Rhodes, 1991; Vigueras et al., 2008) suggested that this species is able to form a biofilm. Concordant with our results, Okada et al. (1995) showed that Purpureocillium

lilacinum is a dimorphic species and is able to form an Acremonium-state in and/or on agar media. This Acremonium-state phenotypically resembles Fusarium solani, a fungal pathogen causing severe corneal disease and the causal agent of an outbreak of lens-associated keratitis. Remarkably, the most frequent manifestation of Purpureocillium lilacinum is also keratitis (Pastor & Guarro, 2006), suggesting that both species might have similar properties besides their phenotypic similarity. In this respect, it needs to be noted that Imamura et al. (2008) showed that F. solani has the ability to form biofilms on lenses; however, this appears to be strain rather than species dependent. Paecilomyces Carbachol can cause hyalohyphomycosis, and two species, Purpureocillium lilacinum (=P. lilacinus) and P. variotii, are the most frequently encountered (Walsh et al., 2004; Houbraken et al., 2010). The phylogenies described here and elsewhere explain why some treatments will work for one species and fail for the others. Major differences in antifungal susceptibility profiles were found between P. variotii and Purpureocillium lilacinum in vitro. Amphotericin B showed good activity against P. variotii and related species in vitro, as was the case for flucytosine (Aguilar et al., 1998; Castelli et al., 2008; Houbraken et al., 2010).