The aim of this study was to determine the biofilm formation, the extracellular enzymatic activities of 182 clinical isolates of the Candida parapsilosis complex. Molecular identification of the C. parapsilosis species complex was performed using PCR RFLP of SADH gene and PCR sequencing of ITS region. The susceptibility of ours isolates to antifungal agents and molecular mechanisms underlying azole resistance were evaluated. 63.5% of C. parapsilosis were phospholipase positive with moderate activity for the majority of strains. None of the C. metapsilosis or C. orthopsilosis isolates was able to produce phospholipase. Higher caseinase activities were detected in C. parapsilosis (Pz = 0.5 ± 0.18) and C. orthopsilosis (Pz = 0.49 ± 0.07) than in C. metapsilosis isolates (Pz = 0.72 ± 0.1). 96.5% of C. parapsilosis strains and all isolates of C. metapsilosis and C. orthopsilosis produced gelatinase. All the strains possessed the ability to show haemolysis on blood agar. C. metapsilosis exhibited the low haemolysin production with statistical significant differences compared to C. parapsilosis and C. orthopsilosis. The biofilm forming ability of C. parapsilosis was highly strain dependent with important heterogeneity, which was less evident with both C. orthopsilosis and C. metapsilosis. Some C. parapsilosis isolates met the criterion for susceptible dose dependent to fluconazole (10.91%), itraconazole (16.36%) and voriconazole (7.27%). Moreover, 5.45% and 1.82% of C. parapsilosis isolates were respectively resistant to fluconazole and voriconazole. All strains of C. metapsilosis and C. orthopsilosis were susceptible to azoles; and isolates of all three species exhibited 100% of susceptibility to caspofungin, amphotericin B and 5-flucytosine. A combination of molecular mechanisms, including the overexpression of ERG11, and genes encoding efflux pumps (CDR1, MDR1, and MRR1) were involved in azole resistance in C. parapsilosis.

The aim of our study was to detect free-living Amoebae (FLA) by morphological methods and to identify Acanthamoeba spp. by PCR in the dental unit water lines (DUWL). Materials and methods: it was a prospective study dealing with 196 water samples collected from DUWL (94 samples taken in the early morning before materials flush and patient consultations and 102 samples taken after consultations). At the same time, 39 samples from tap water were realized. Results: 135 (69 %) samples were positives by the morphological study with morphotypical diversity. The predominant morphotype was the monopodial (39.2 %). 18 strains of Acanthamoeba spp. were detected in DUW (13.3 %) and three strains in tap water (10 %). The amplification of 18S rDNA gene of these strains of Acanthamoeba spp. was positive for all samples. Conclusion: the FLA and Acanthamoeba were isolated both in tap water and in dental unit. The amoeba pathogenicity has not been demonstrated after oral or dental contamination; but the presence of intracellular and pathogenic bacteria in the amoeba could be a source of microbiological risks for patients in case of deep dental care or immunodepression. The improvement of this dental unit was necessary by putting a filter of 0.2 microns porosity before the arrival of the water in hand-pieces allowing the limitation of FLA passage. L’objectif de notre étude a été de détecter les amibes libres par des méthodes morphologiques et d’identifier Acanthamoeba spp. par PCR dans l’eau des unités dentaires. Matériel et méthodes : il s’agit d’une étude prospective portant sur 196 prélèvements d’eau à partir des circuits dentaires (94 échantillons réalisés avant purge et consultation des malades et 102 échantillons après consultation des malades) et 39 échantillons d’eau de robinet. Résultats : l’étude morphologique a permis de détecter les amibes libres dans 69 % des échantillons. Le morphotype prédominant était le monopodial (39,2 %). 18 souches d’Acanthamoeba ont été détectées dans l’eau du circuit dentaire (13,3 %) et trois souches dans l’eau de robinet (10 %). L’amplification du gène 18S de l’ADN ribosomal de ces souches d’Acanthamoeba spp. a été positive dans 100 % des cas. Conclusion : les amibes libres, dont Acanthamoeba, ont été isolées aussi bien dans l’eau de robinet que dans les unités dentaires. Des cas d’infections amibiennes directement attribuables aux soins dentaires n’ont pas été démontrés, cependant, la présence de bactéries intracellulaires au sein des amibes libres doit être considérée comme un risque potentiel surtout chez les patients immunodéprimés. L’assainissement de ces unités s’impose au moins par la mise en place d’un filtre de porosité 0,2 microns avant l’étape d’entrée de l’eau dans les circuits dentaires afin de limiter l’éventuel passage des amibes libres.