A. Fathallah

Evaluation of Chitine synthase (CHS1) polymerase chain reaction assay in diagnosis of dermatophyte onychomycosis.

BACKGROUND Onychomycosis is one of the most prevalent dermatophytic diseases. Mycological methods used in the conventional diagnosis may not be optimal. PCR was reported as a reliable alternative in the diagnosis of dermatophytosis. MATERIALS AND METHODS A PCR method based on the amplification of the chitin synthase 1 gene was developed. The study included 119 strains of dermatophytes and non dermatophytic fungi, eight dermatophytic reference strains and 201 nail specimens from patients with dermatophytic onyxis. DNA extraction was carried out by using the QIAamp DNA extraction kit (Quiagen). RESULTS PCR positivity was based on the production of a specific 432 bp fragment. None of the investigated non dermatophytic strains was positive. Sensitivity of PCR was higher as compared to mycological examination (90.5% vs. 81.1%). PCR was positive in 31 onyxis cases with positive direct examination but negative or contaminated culture. In contrast, PCR was negative in 10 cases where both direct examination and culture were found positive. CONCLUSION PCR is an adequate tool for the diagnosis of dermatophytic onychomycosis. It is much adapted to cases where culture is negative or contaminated by overgrowing molds, which makes the identification of the causal agent problematic.

Clinical and mycological features of onychomycosis in central Tunisia: a 22 years retrospective study (1986-2007).

Onychomycosis is the most frequently encountered nail disease and may be difficult to diagnose and treat. The objective of this study was to determine the prevalence, the clinical and mycological characteristics of onychomycosis in central Tunisia. It is a retrospective study performed over a 22‐year period (1986–2007). It included 7151 patients (4709 women and 2442 men) with suspected fingernails and/or toenails onychomycosis. The patients were referred to the Mycology‐Parasitology Laboratory of Farhat Hached hospital in Sousse for mycological examination. Both direct microscopy and culture of the nail material were performed to diagnose and identify the causative fungal species. Onychomycosis was confirmed in 78.6% of investigated patients (5624/7151). The positivity rate was higher in women as compared with men. In both men and women, fingernails were most frequently involved than toenails. No significant relation was found between gender and toenails onychomycosis, whereas fingernails were frequently involved in women. As far as aetiological agents are considered, dermatophytes, yeast and moulds were responsible for 49.9%, 47.4% and 2.7% of onyxis cases respectively. In fingernail infections, yeast were the most frequent fungi (83.6%), Candida albicans being the leading species (51.6%). In contrast, in toenail infections, dermatophytes were more frequent (74.1%). Trichophyton rubrum was by far the dominant species (88.1%). Yeast were observed more frequently in women whereas dermatophytes were more common in men. Moulds were involved in 4.2% of cases. The most frequent species were Aspergillus sp. and Chrysosporium sp. Onychomycosis is a frequent disease in central Tunisia. T. rubrum is the predominant agent in toenails infection and yeast, mainly C. albicans, in fingernails onychomycosis.

Geotrichum capitatum septicemia in patients with acute myeloid leukemia. Report of three cases

Geotrichum capitatum infection is uncommon, and has been exclusively reported in immunocompromised patients. The prognosis is poor with a mortality rate ranging from 50 to 90%. We report 3 cases of Geotrichum capitatum fungemia in neutropenic patients receiving chemotherapy for acute myeloblastic leukemia. The infection was successfully cured with voriconazole in 1 case and was fatal in the 2 remaining cases despite treatment with amphotericin B.

Immunochromatographic rK39 strip test in the serodiagnosis of visceral leishmaniasis in Tunisia

The performance of the rK39 strip test in the diagnosis of Tunisian visceral leishmaniasis (VL) was evaluated and compared with that of immunofluorescent antibody test (IFAT). A total of 929 sera, including 574 from VL patients, 54 from cutaneous leishmaniasis (CL) patients, 42 from patients with other protozoan diseases, 152 from patients with non-parasitic diseases and 107 from healthy controls, were used in the study. The sensitivity and specificity of the rK39 strip test were 87.1 and 94.4%, respectively. Sixteen CL sera showed positive results, suggesting that the rK39 strip test is not restricted to Leishmania donovani complex detection. IFAT was comparatively more sensitive (98.9%) but slightly less specific (90.7%). Despite cross-reactivity shown by CL sera, the rK39 strip test can be recommended for the routine diagnosis of VL in Tunisia, as VL and CL are distinct clinical entities.

IgG Western Blot for Confirmatory Diagnosis of Equivocal Cases of Toxoplasmosis by EIA-IgG and Fluorescent Antibody Test

The performance values of available techniques used in serodiagnosis of toxoplasmosis are satisfactory but they raise problems of equivocal and discordant results for very low IgG titers. Recently marketed, LDBio-Toxo II IgG Western blot (IB) showed an excellent correlation with the dye test. We estimated the proportion of equivocal and discordant results between the enzyme immunoassay Platelia Toxo IgG (EIA-IgG) and fluorescent antibody test (FAT) and assessed the usefulness of the IB as a confirmatory test. Out of 2,136 sera collected from pregnant women, 1,644 (77.0%) tested unequivocally positive and 407 (19.0%) were negative in both EIA-IgG and FAT. The remaining 85 (4%) sera showed equivocal or discordant results. Among them, 73 (85.9%) were positive and 12 (14.1%) were negative in IB. Forty-one (89.1%) equivocal sera in EIA-IgG and 46 (86.8%) equivocal sera in FAT were positive in IB. Reducing the cut-off values of both screening techniques improved significantly their sensitivity in detecting very low IgG titers at the expense of their specificity. In conclusion, equivocal results in routine-used techniques and their discordance in determination of the immune status in pregnancy women were not uncommon. IB test appeard to be highly useful in these situations as a confirmatory technique.

Neonatal invasive candidiasis in Tunisian hospital: incidence, risk factors, distribution of species and antifungal susceptibility

The aim of our study was to assess epidemiological features of neonatal invasive candidiasis in Farhat Hached hospital of Sousse, Tunisia, including incidence, risk factors, mortality, species distribution and antifungal susceptibility. Laboratory data from 1995 to 2010 and medical records of 127 invasive candidiasis cases were reviewed. We tested the susceptibility of 100 Candida sp isolates by using ATB fungus®3 and to fluconazole by using E‐test® strips. A total of 252 cases of neonatal invasive candidiasis occurred over the study period. The incidence increased 1.8‐fold from 1995 to 2006 and decreased fourfold from 2007 to 2010. Candida albicans was the predominant species up to 2006 and a shift in the species spectrum was observed with increase of the non‐albicans species mainly C. parapsilosis. The agreement between the ATB Fungus® and the E‐test® for determining fluconazole susceptibility was high. All tested isolates were susceptible to fluconazole, flucytosine, amphotéricine B and voriconazole and the itraconazole resistance rate was 5%. The mortality rate was 63%. The invasive candidiasis incidence increased from 1995 to 2006 and decreased from 2007 to 2010. The spectrum of Candida species and the lack of fluconazole‐resistant strains argue for the usefulness of fluconazole as an empiric treatment.

Systemic neonatal candidosis: the karyotyping of Candida albicans strains isolated from neonates and health-workers

Candida albicans has become an important cause of nosocomial infections in neonatal intensive care units (NICUs). The aim of the present study was to compare C. albicans strains isolated from neonates (NN) suffering from systemic candidosis and from nurses in order to determine the relatedness between NN and health workers’ strains. Thirty‐one C. albicans strains were isolated from 18 NN admitted to the NICU of the neonatology service of Farhat Hached Hospital of Sousse, Tunisia and suffering from systemic candidosis, together with five strains recovered from nurses suffering from C. albicans onychomycosis. Two additional strains were tested, one from an adult patient who developed a systemic candidosis and the second from an adult with inguinal intertrigo. All strains were karyotyped by pulsed‐field gel electrophoresis (PFGE) with a CHEF‐DR II system. Analysis of PFGE patterns yielded by the 38 strains tested led to the identification of three pulsotypes that were designated I, II and III, and consisted of six chromosomal bands with a size ranging from 700 to >2500 kbp. The most widespread was the pulsotype I, which was shared by 17 NN and the five nurses’ strains. The identity between NN and nurses’ strains is very suggestive of a nosocomial acquisition from health‐workers.

Assessment of Immunoblot for Early Detection of Seroconversion in Pregnant Women

The recently commercialized LDBIO Toxo II IgG® immunoblot test has been shown to be very reliable in the early detection of toxoplasmic seroconversion in pregnant woman. A positive result is defined by the presence of at least three among the five following bands: 30, 31, 33, 40 and 45 kDa, the 30 kDa band being required as a positivity criteria. Moreover, it has been reported that the detection of the sole 30 kDa band was sufficient for this purpose. We report herein the result of serologic follow-up of three initially seronegative pregnant woman by using ELISAIgG, IFAT-IgG, ELISA-IgM and LDBIO Toxo II IgG®. In two of them, seroconversion was highly suspected on the detection of 30 kDa band and positivity of IgM test and further confirmed by the positivity of conventional tests for IgG. In contrast, in the third case, despite the appearance of the 30 kDa band during the follow-up, seroconversion was discarded as ELISA-IgG and IFAT-IgG tests remained negative and only one additional band was later detected on LDBIO Toxo II IgG®. Our findings suggest that the detection of the 30 kDa band together with the positivity of IgM test can be considered as a seroconversion criteria but confirmation by further positivity of conventional tests is recommended.

Hydatid Recurrence Medically Treated by Albendazole

CASE REPORT Hydatid Recurrence Medically Treated by Albendazole Imen Khammari, Mohamed Amine El Ghali, Salsabil Nasri, Imen Dhib, Hamed Chouaieb, Alia Yaacoub, Moncef Ben Said, Rached Letaief and Akila Fathallah Laboratory of Parasitology, Faculty of Medicine of Sousse, Mohamed Karoui street, 4002, Sousse, Tunisia General and Digestive Surgery Department, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse, 4000, Tunisia Laboratory of Parasitology, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse, 4000, Tunisia

Dermatophytic disease: Report of a Tunisian case caused by a sterile dermatophyte identified as Trichophyton Rubrum by its1 and its4 sequencing

Dermatophytic disease is a rare chronic mycosis characterized by polymorphic cutaneous lesions and possible visceral invasion, and is associated with immunodeficiency and refractoriness to drug treatment. We report herein a dermatophytic disease tunisian case caused by a sterile dermatophyte further identified as Trichophyton rubrum by ITS1 and ITS4 sequencing. The case we report herein highlights the usefulness of molecular techniques in identification of causative agent when the mycological criteria are lacking.