SummaryCandida albicans is one of the most medically important fungi because of its high frequency as a commensal and pathogenic microorganism causing superficial as well as invasive infections. Strain typing and delineation of the species are essential for understanding its biology, epidemiology and population structure. A wide range of molecular techniques have been used for this purpose including non-DNA-based methods (multi-locus enzyme electrophoresis), conventional DNA-based methods (electrophoretic karyotyping, random amplified polymorphic DNA, amplified fragment length polymorphism, restriction enzyme analysis with and without hybridization, rep-PCR) and DNA-based methods called exact typing methods because they generate unambiguous and highly reproducible typing data (including microsatellite length polymorphism and multi-locus sequence typing). In this review, the main molecular methods used for C. albicans strain typing are summarized, and their advantages and limitations are discussed with regard to their discriminatory power, reproducibility, cost and ease of performance.

Onychomycosis is one of the most prevalent dermatophytic diseases. Mycological methods used in the conventional diagnosis may not be optimal. Multiplex (MX) PCR was reported as a reliable alternative. Dermatophyte gene sequence records were used to design a MX PCR for detection and identification of dermatophytes in nail specimens. A MX PCR method based on the amplification of the chitin synthase 1 and internal transcribed spacer genes was developed. The study included 93 strains of dermatophytes and non-dermatophytic fungi, six dermatophytic reference strains and 201 nail specimens from patients with dermatophytic onyxis. DNA extraction directly from nail samples was carried out by using the QIAamp DNA extraction kit (Quiagen). A set of primers was designed and their specificity was assessed. MX PCR detected the causal agent in specimens from which Trichophyton rubrum and T. interdigitale grew in culture and also identified a dermatophyte species in an additional 32 specimens that were negative in microscopy and culture. None of the investigated non-dermatophytic strains was positive. Sensitivity of MX PCR was higher as compared to mycological examination (97% vs. 81.1%). MX PCR for direct detection of dermatophytes from nail samples yielded mixed flora in 32.8% of samples. MX PCR proved sensitive and adequate for the diagnosis of dermatophytic onychomycosis. It is much adapted to cases where culture is negative or contaminated by overgrowing moulds, which makes the identification of the causal agent problematic.

Trichophyton violaceum remains the most common etiological agent of adult TC in Tunisia. Microsporum canis is rising rapidly most notably due to the high frequency of asymptomatic carriage by domestic animals [corrected].

Purpureocillium lilacinum is a saprophytic fungus found in soil and decaying organic matter, but has been reported as an emerging pathogen in immunocompromised patients and following surgical procedures. Infections caused by this mold are often difficult to treat because of its intrinsic resistance to conventional antifungal agents and variable susceptibility to novel triazoles. In immunocompetent subjects, infections caused by P. lilacinum are unusual and mainly involve the skin. We describe herein a case of cutaneous hyalohyphomycosis due to this fungus in an immunocompetent girl without any predisposing risk factors and review the previously reported cases in immunocompetent hosts.

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