Onychomycosis by Paecilomyces lilacinus in a patient with leukonychia

Paecilomyces lilacinus, a filamentous fungus living saprophytic in the environment, very rarely causes infection in immunocompetent humans, mostly ocular or cutaneous and sub-cutaneous infections.The fungal isolates usually show low susceptibility to conventional antifungal drugs in vitro and variable susceptibility to novel triazoles. During a period of 2 years, 4 cultures of nail fragments were grown from a 41 years old female on modified Sabouraud/Dextrose agar (S.D.A.) (CAF bioMérieux, CAF+CEX Biolife). Cultures were continued in suspension and the hyphae stained with lactophenole blue analysed microscopically. 2 samples were tested with molecular methods, i.e. DNA extraction, amplification of internal transcribed spacer (ITS) region 1 and 2 and automated sequencing. The sequence results were evaluated using a validated reference database for humanpathogenic fungi. Additionally the BLAST algorithm on NIH database GenBank was used. A growth of a filamentous hyaline fungus with white colonies and lila shade was observed in all samples. The presence of Penicillium like conidiophores with divergent long terminal phialides was seen with little elliptical conidia. DNA sequencing determined the species as Paecilomyces lilacinus with 99% homology with GenBank isolate AY213667. The infection of the right hallux did not improve by systemic (Lamisil/terbinafine) and local treatment (Locetar/amorolfin nail lacquer).Also change to Sporanox/itraconazol only led to deterioriation, so finally the extraction of the nail had to be performed given the known difficulties with treatment described in the literature. This case highlights the usefulness of molecular techniques, especially use of the highly discriminative ITS region for fungal typing.