No abstract

The distribution of dermatophytes varies in different countries and geographical areas depending on several factors. To determine the frequency of aetiological agents and the clinical variants of dermatophytoses, we carried out a study between 1998 and 2007. Out of 25 432 subjects suspected to have superficial mycoses, 9960 (39.2%) were affected with dermatophytoses; 14957 positive samples were obtained. The mean age was 35.7 years (range: 21 days to 97 years). Sex ratio was 0.9. Our patients were from urban regions in 81.9% of cases. The most common type of infection was onychomycosis (30.3%), followed by tinea pedis (24.8%), intertrigo (21.7%), tinea corporis (11.4%) and tinea capitis (9.6%). Fifteen patients had generalised dermatophytosis. Hadida and Schousboe disease was diagnosed in one case with lethal evolution. The most isolated dermatophyte was Trichophyton rubrum (74.5%), followed by T. violaceum (7.9%), T. mentagrophytes (7.5%), Microsporum canis (3.8%), Epidermophyton floccosum (0.7%) and T. verrucosum (0.54%). Other species were occasionally isolated: T. schoenleinii, T. tonsurans, M. audouinii and M. ferrugineum. The prevalence of dermatophytoses remains high in our country (996 cases/year). Trichophyton rubrum is the predominant causal agent. However, zoophilic agents become more prevalent. Epidemiological surveys are an essential tool for developing strategies for infection control.

We investigated six microsatellite markers to type 85 unrelated and 118 related isolates of Candida glabrata from 36 patients. Three new markers were selected from the complete sequence of CBS138 and three previously described markers, RPM2, MTI and ERG3 were used. We found a genetic diversity of 0.949 by combining four of them. By applying the new microsatellite markers GLM4, GLM5 and GLM6 we were able to discriminate 29 isolates, originally identified by the more established markers, RPM2, MTI and ERG3. When epidemiologically closely related isolates from 36 patients were typed, 25 patients (72%) exhibited identical or highly related multilocus genotypes. We noted a microvariation in 4 of the patients. This minor change of one locus could be explained by a single step mutation. Since one of these patients had not received antifungal treatment; thus, the relationship between genome variation and antifungal therapy remains controversial. We can conclude from our analysis of these new microsatellite markers that they are highly selective and therefore should be considered as a useful typing system for differentiating related and unrelated isolates of C. glabrata, as well as being able to detect microvariation.

BackgroundThe aim of this study was to determine the biofilm formation, the extracellular enzymatic activities of 182 clinical isolates of the Candida parapsilosis complex. MethodsMolecular 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.Results63.5% 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.ConclusionsA 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.

Whether in vitro antifungal susceptibility findings correlate with the outcome of patients with invasive aspergillosis (IA) remains debated. This study aimed to test whether IA patients' outcomes were associated with in vitro susceptibility results. To do so, we determined the in vitro susceptibility to amphotericin B (AMB) of 37 Aspergillus flavus isolates from 14 patients with haematological malignancies diagnosed with proven or probable IA, of which 13 were treated with AMB deoxycholate. Minimal inhibitory concentrations (MICs) were determined by Etest with the isolates classified as in vitro sensitive (AMB-S) or resistant (AMB-R) if their MICs were < 2 or ≥ 2 mg/l, respectively. The association of the patients' death with primary disease, administered antifungal treatment, and infection with AMB-R A. flavus was tested using generalized estimating equations logistic regression. We assessed AMB-R in 31/37 (84%) isolates. In the patients treated with AMB, the survival rate was 2/3 (67%) and 2/9 (22%) for those infected with AMB-S or AMB-R A. flavus, respectively. Both infection with AMB-R A. flavus (P = 0.014) strain and acute myelocytic leukaemia as the underlying primary disease (P = 0.036) were independent predictors of death. Our findings indicate that in vitro resistance predicts a poor outcome in patients with A. flavus invasive disease treated with AMB. Recent advances in non-culture-based microbiological methods should not discourage efforts to obtain in vitro antifungal susceptibility results, which are critical for the choice of antifungal therapy in patients with IA.

Trichophyton verrucosum is the most frequent etiologic agent of cattle dermatophytosis. Throughout the world, it was the second most common agent of zoophilic dermatophytes in human. The aim of our study was to evaluate the efficacy of the PCR- RFLP and PCR-sequencing methods for the identification and differentiation of T. verrucosum strains.Thirty-six clinical strains identified by morphological characteristics as T. verrucosum were isolated from patients referred to parasitology-mycology laboratory of Sfax University Hospital. Identification of our strains by conventional methods was confirmed by molecular methods in 94.4% of cases. Two strains were reclassified as T. violaceum PCR products digested with HinfI produced three profiles and two patterns with MvaI. Sequence analysis revealed a polymorphism in the ITS1and 5.8S regions. Analysis and alignment of consensus sequences has distinguished two types of genotypes among our T. verrucosum strains. The ITS type I was the dominant genotype (93.7%). Phylogenetic study showed that one cluster comprised T. verrucosum strains with ITS type I and species of T. mentagrophytes complex. It was related to Arthroderma vanbreuseghemii complex. The other cluster contained the two T. verrucosum strains with ITS type II, and was related to Arthroderma benhamiae complex. In this study, most of T. verrucosum isolates were type I, dissimilar to others rare studies where type II has been the most common. Specie and strain differentiation is relevant because it helps in prescribing the correct treatment and determining the source of the infection.

In our institution, C. tropicalis was the most frequent specie isolated from the bloodstream. Caspofungin had an excellent in vitro activity against Candida isolates and was the drug of choice among fluconazole-resistant isolates.

Yarrowia lipolytica is weakly pathogenic yeast, which is rarely isolated from the blood. We report unusual cases of Y. lipolytica fungemia occurred between October 2012 and June 2014 in the intensive care unit (ICU) of the UH Habib Bourguiba Sfax. During this period, 55 cases of Y. lipolytica septicemia were diagnosed. There were 44 men and 11 women (sex ratio = 4).The median age was 43 years. The broad-spectrum antibiotics (100 %), the catheterization (96 %), and the prolonged hospitalization in ICU (91 %) were the main risk factors. Patients were hospitalized in ICU, mostly, for polytraumatism (45.4 %), pneumopathy (9 %), and post-operative complications (7 %). Fever unresponsive to broad-spectrum antibacterial therapy was the predominant sign of infection (83.6 %). Y. lipolytica was isolated in one or several blood cultures (14.5 %) and in the catheter tip culture of nine patients (16.3 %).Treatment was based on intravenous amphotericin B (58.2 %), fluconazole (45.4 %) and/or removal catheter (69 %). Apyrexia or blood cultures sterilization was obtained for 34 patients (61.8 %). Y. lipolytica candidemia is an opportunistic and emerging human yeast pathogen. It can reach to the bloodstream of immunocompromised or critically ill patients during hospitalization through intravascular catheterization. Further clinical data need to be evaluated for formulating management strategies of seriously ill patients infected with uncommon fungal agents.