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ABSTRACT: The potential for environmentally friendly nano-additives based drilling fluids is extended here in the context of the ongoing EU project ‘ORCHYD’ where a hybrid drilling technology is developed by combining High Pressure Water Jet (HPWJ) and Percussive Drilling to improve the efficiency of deep geothermal drilling. In this work, different types of nanomaterials such as graphene oxide, hybrid nano silica and their composite nanomaterials are used as additives in a water-based drilling fluid. The influence of additives on the rheological properties and the friction of the drilling fluid has been investigated. The laboratory results showed that an increase in the concentration of additives will increase the viscosity of fluids. A significant reduction in the coefficient of friction (during wear testing of steel material) was also revealed with the addition of GO and chemical functionalization. The need for further characterizing and the perspective to upscale the enhanced nano-additives based fluids for HPWJ and percussive drilling application, in deep geothermal conditions, are discussed. 1. INTRODUCTION This study is performed in the context of the EU project ORCHYD, https://www.orchyd.eu/proiect/, where an innovative drilling tool combining (high pressure water jetting and percussive drilling) will be developed to increase hard rock drilling rates, in deep geothermal wells. The potential of new green additives to the drilling fluids is thus investigated to account for the best compromise for efficient jetting, cutting and transport of the rock particles, and the lifetime extension the drilling tools. Deep geothermal reservoirs are being targeted for renewable energy supply worldwide (Huttrer, 2021), however the high pressures and high temperatures in deep geothermal wells impose significant challenges for desiring drilling fluids. Over the past decade, various additives such as polyacrylamide, organic modified clays, poly carboxylic acids, asphaltic compounds, treated lignite have been used in the drilling fluid to optimize the rheological properties, filtration control and reduce the fluid loss, shale inhibitors and thereby improving wellbore stability (Boyou et al., 2019; Vryzas et al. 2017). However, most of the polymer-based materials degraded thermally and chemically at relative low temperature, which lowers their effectiveness.

Free living amoebas (FLA) are opportunistic pathogen found in different water sources in the environment. The aim of this study was to investigate the prevalence of free living amoeba in different samples of domestic water reserves (DWR) in Sfax region from Tunisia. It was a prospective study dealing with 486 water samples collected from different DWR. After filtration through a cellulose acetate membrane samples were cultured on non-nutrient agar and the FLA were detected and strained with Giesma, Trichrome and red nuclear stain for morphological and morphotypic studies. FLA were found in 62% of samples. The Acanthopodial morphotype was detected in 43%, Polytactic (38%), Monotactic (28%), Fan-shaped (17%), Rugose (11%), Dactilopodial (10%) and Eruptive (9%). These results demonstrate that domestic water reserves are a significant source of the FLA and maintenance of DWR is recommended.

In the southern Tunisia Oasis, we conducted 211 water with drawals from various water traffic sites. This water is used for agriculture, swimming or various other human activities. Acanthamoeba genus was detected in 82% of collected samples. Sequencing of the amplification products with primers P892C/P892 has allowed us to detect genotypic variation with predominance of T4 genotype (51%) and presence of the genotypes T14, T5, T3, T16, T15, T10, T11, T9 and T7. They T4, T3, T5, T15, T11 and T10 genotypes have a high potential for pathogenicity and a very high degree of virulence due to their production of serine proteases and extracellular cysteine enzymes involved in tissue degradation of the host. T4 genotype was the most abundant in the environment as well as in infections caused by Acanthamoeba spp. T5 genotype was ranked second and T3 genotype was less abundant in the environment and its pathogenicity is discussed. Acanthamoeba strains with the genotypes T16, T9 and T7 were considered non pathogenic. In fact, they have been isolated only from the environment. However, for these strains, their role as a reservoir can be a real risk to human health.

To study the influence of environmental and biological factors on levels of contamination by Escherichia coli, Salmonella spp., hepatitis A virus (HAV) and norovirus in clam production areas, an epidemiological study was conducted on 791 samples of live clams (Ruditapes decussatus), 539 of which were sent for bacteriological analysis and 252 for detection of norovirus and HAV. These samples were collected in different production areas in the Sfax region of southern Tunisia over four consecutive years, from March 2013 to December 2016. The prevalence of positive samples was 36% for E. coli, 11% for Salmonella spp., 19% for norovirus and 3% for HAV. There was a significant correlation between contamination by E. coli and by Salmonella spp., as well as between contamination by noroviruses and by HAV and between contamination by noroviruses and by Salmonella spp. Temperature, the presence of migratory birds and tourism are the main factors affecting microbial contamination levels in bivalve molluscs.Pour étudier l’influence des facteurs environnementaux et biologiques sur le niveau de contamination des zones de production des palourdes par Escherichia coli, Salmonella spp., le virus de l’hépatite A (VHA) et les norovirus, une enquête épidémiologique a été réalisée en utilisant 791 échantillons de palourdes vivantes (Ruditapes decussatus), dont 539 destinés à des analyses bactériologiques et 252 destinés à la détection des norovirus et du VHA. Ces échantillons ont été collectés dans différentes zones de production de la région de Sfax (Sud de la Tunisie) durant quatre années consécutives, du mois de mars 2013 au mois de décembre 2016. La prévalence d’échantillons positifs était respectivement de 36 % pour E. coli, de 11 % pour Salmonella spp., de 19 % pour les norovirus et de 3 % pour le VHA. La corrélation était fortement significative entre la contamination par E. coli et celle par Salmonella spp., ainsi qu’entre la contamination par les norovirus et celle par le VHA et entre la contamination par les norovirus et celle par Salmonella spp. La température, la présence d’oiseaux migrateurs et l’activité touristique sont les principaux facteurs associés au niveau de contamination microbienne des mollusques bivalves.Los autores describen una investigación epidemiológica encaminada a estudiar la influencia de los factores ambientales y biológicos sobre el nivel de contaminación de zonas de producción de almejas por Escherichia coli, salmonelas, virus de la hepatitis A (VHA) y norovirus. Para ello se llevó a cabo una investigación epidemiológica: en el curso de cuatro años consecutivos (de marzo de 2013 a diciembre de 2016), se obtuvieron en distintas zonas productivas de la región de Sfax (sur de Túnez) 791 muestras de almejas vivas (Ruditapes decussatus), de las que 539 fueron sometidas a análisis bacteriológicos y 252 sirvieron para detectar norovirus y el VHA. La prevalencia de muestras positivas resultó respectivamente del 36% para E. coli, del 11% para Salmonella spp., del 19% para los norovirus y del 3% para el VHA. Había una correlación muy significativa entre la contaminación por E. coli y la contaminación por salmonelas, y también entre la presencia de los norovirus y la del VHA y entre la de los norovirus y la de salmonelas. La temperatura, la presencia de aves migratorias y la actividad turística son los principales factores asociados al nivel de contaminación microbiana de los moluscos bivalvos.

Human Platelet Antigens (HPA) are of considerable interest in obstetric transfusion medicine and anthropological genetics. This study aims to provide clinicians with a detailed database of HPA antigenic variants, which allows them to estimate the probability of allo-immunisation of each antigen. In addition, it aims to make an interethnic comparison of the Tunisian population with other populations.The target population consists of 324 healthy and unrelated Tunisian blood donors recruited from the National Blood Transfusion Center in Tunis. DNA extraction was performed by the Salting Out method and molecular genotyping was performed by the PCR-SSP technique. The statistical analysis was performed using two approaches: manual calculation and computerized calculation. Phylogenetic trees were constructed through the use of Standard Genetic Distances that were calculated from allelic frequencies.With the exception of the HPA-4 system, statistical analysis showed that all HPA systems are polymorphic especially the two systems HPA-3 and HPA-15. The inter-ethnic analysis showed that Tunisians are closer to North Africans and Caucasians than Sub-Saharan and Asian populations, which shows genetic mixing between Tunisians, Arabs, Europeans and Africans.The results of this study could be exploited to prepare a ready-to-use genotyping plate dedicated to HPA antigens, with the aim of ensuring better management, especially for polytransfused patients.

International audience; This paper presents the results of simple and double indentation tests conducted on three hard rocks: granite, limestone and sandstone. The main objective is to analyze the rock behavior under indentation test in relation with the physical and microstructural properties. First, the experimental set-up used during the tests is described as well as the sample preparation. Then, an image analysis based technique is applied on thick sections made from the tested samples in order to evaluate the size of indentation-induced cracked zone and to assess the crack types (vertical or sub-horizontal) below the indenter. The interpretation of the results was made on two levels. First, several physical parameters (energies and displacements) have been derived from the so obtained experimental indentation curves. Very high correlations were found between the loading, indentation and specific energies versus the plastic displacement. Second, cracked zone radius was estimated showing a very high correlation to the specific energy and governed by the physical and mineralogical properties of the tested rocks. Finally, the analysis of double indentation tests proved that changing the distance between two adjacent inserts allows the determination of the optimal spacing producing overlay of cracked zones and causing rock damage and large chip departure.

Malassezia folliculitis is caused by the invasion of hair follicles by large numbers of Malassezia cells. Several Malassezia researches still use cultures, morphology and biochemical techniques. The aim of this study was to identify Malassezia species isolated from patients diagnosed with folliculitis, at the Parasitology and Mycology Laboratory of Sfax University Hospital, and to explore the genetic diversity of Malassezia by using PCR-RFLP and PCR-sequencing targeting the rDNA region of the Malassezia genome. Specimens were taken from 27 patients with Malassezia folliculitis. For the molecular identification, PCR amplification of the 26S rDNAD1/D2 region was carried out using the Malup and Maldown primers and three restriction enzymes (BanI, MspI and HeaII) for RFLP analysis. The nucleotide sequences of each isolate were compared to those in the NCBI GenBank by using BLASTIN algorithm. Three species of Malassezia yeasts were identified among the 31 Malassezia strains isolated: M. globosa (83.9%), M. sympodialis (12. 9%) and M. furfur (3.2%). The sequence analysis of M. globosa showed six genotypes. There is a high genotypic variability of M. globosa colonizing patients with folliculitis.

15 pages; International audience; Drill pipe in a curved section of the drilled well is considered as a rotating hollow cylinder subjected to bending and tension loads. So in this paper, the stress intensity factors and the fatigue growth of a circumferential semi-elliptical surface crack in a hollow cylinder subjected to rotary bending and tension are studied. A stress intensity factor database for three loading cases is build for numerous configurations using 3D Finite Element Models. The crack propagation model employs the Walker fatigue growth rate law. Using this model, we can study the evolution of parameters characterizing the process of crack propagation.

The HLA polymorphism is a powerful genetic tool to study population origins. By analysing allele frequencies and haplotypes in different populations, it is possible to identify ethnic groups and establish the genetic relationships among them.The Berber (endogenous Tunisians) HLA class I and class II genotypes were analysed and compared with those of Mediterranean and Sub-Saharan African communities using genetic distances, Neighbour-Joining dendrograms, correspondence and haplotype analysis.One hundred and five unrelated Berbers were typed for HLA class I (A, B) and class II (DRB1, DQB1) gene alleles using reverse dot-blot hybridization.High frequencies of A*0201 (24.76%), A*3402 (22.38%) and B*44 (32.85%) alleles were recorded for Berbers, the highest recorded for Mediterranean and North African populations. This study shows a close relatedness of Tunisian Berbers to other Tunisians, North Africans and Iberians.The apparent relatedness of Tunisian Berbers to present-day (North African) Tunisians, Algerians and Moroccans suggests that the Arab invasion of North Africa (7(th)-11(th) centuries AD) did not significantly impact the genetic makeup of North Africans. Furthermore, Tunisian Berbers appear to be closely related to Iberians (Spaniards and Basques), indicating that the 7(th) century AD gene flow of invaders was low in Iberians and that the main part of their genetic pool came after the Northward Saharan migration, when hyper-arid conditions were established in Sahara (before 6000 BC). Other studied populations belong to the old Mediterranean substratum, which has been present in the area since pre-Neolithic times. This study indicates a higher proportion of Iberian than Arab ancestry in Tunisian Berbers, which is of value in evaluating the evolutionary history of present-day Tunisians. Greeks seem to share genetic HLA features (Chr 6) with Sub-Saharans. The relatedness of Greeks to Sub-Saharans has been confirmed by other studies based on chromosome 7 genetic markers.

L’objectif de notre travail a ete de rapporter les particularites epidemiologiques et cliniques des cas de demodecidose diagnostiques dans la region de Sfax. Sur une periode de neuf ans (janvier 2000–decembre 2008), nous avons collige 427 cas de demodecidose sous forme de blepharites (73,2 % des cas) et d’atteinte du visage (26,8 % des cas). L’âge moyen etait de 44 ans. Les femmes etaient legerement plus concernees (56 %) que les hommes. Deux cent quarantetrois parmi 787 cas de blepharite chronique ont ete dus a Demodex sp (30,9 %). Ils ont ete traites par une pommade d’oxyde jaune de mercure (Ophtergine® 1 %). Au niveau du visage, cet acarien a ete isole de lesions erythemateuses et papulopustuleuses prurigineuses touchant surtout les joues (22,1 %), le front (13,4 %) et le nez (11,5 %). Le diagnostic a ete confirme sur la richesse de l’examen parasitologique des squames montrant plus de cinq Demodex sp par centimetre carre et la reponse au traitement a base de metronidazole (Flagyl®) pendant trois mois. Actuellement, un grand nombre d’arguments plaident pour l’incrimination du Demodex sp dans les dermatoses du visage ainsi que dans la blepharite. Il faut donc sensibiliser les dermatologues et les ophtalmologues a penser a cette affection, surtout que la densite du Demodex sp retrouvee par l’examen parasitologique constitue le facteur determinant dans l’instauration d’un traitement anti-Demodex, dont l’efficacite est un argument de plus pour le diagnostic.

The frequency of toxoplasmosis depends on life-style and environment. Our objective was to study different epidemiological, clinical and biological aspects of toxoplasmosis in the Sfax area (Tunisia). This retrospective study has been performed on seria of 40,566 pregnant women in the Parasitology-Mycology Laboratory of Habib-Bourguiba Sfax hospital-Tunisia for 13 years from 1994 to 2006; 1,691 patients presenting with lymphadenopathy; 191 immunocompromised patients (78 HIV infected patients and 113 transplanted patients) and 21 patients presenting clinical signs of ocular toxoplasmosis. In pregnant women, the seroprevalence was 39.3% (15,952/40,567). Among 24,089 seronegative women, only 6,890 (28.6%) had been followed up during their pregnancy. An active toxoplasmosis possibly acquired during pregnancy was detected in 1.3% of cases. Sixteen congenital toxoplasmosis were detected. Toxoplasmosis was confirmed in 13.7% of the 169 patients with lymphadenitis. For HIV positive patients, 11.7% had cerebral toxoplasmosis. It revealed the HIV infection in four cases. Among transplant recipients, one case of active toxoplasmosis was diagnosed in a renal transplant recipient who received transplant from a seronegative donor. Twenty-one patients presenting toxoplasmic retinochoroiditis were treated by subconjonctival injections of clindamycin and systemic corticotherapy at a dose of 1 mg/kg per day. This clinical toxoplasmosis diversity explains the need for bioclinical confrontation to establish diagnosis.

The Duffy blood group system, besides its relevance in transfusion medicine, is of major interest for population genetics. In fact, the Duffy molecule is the only red cell receptor for Plasmodium vivax, thus the fixation of FY*silent allele in western south-Saharan Africa resulted in the absence of this type of malaria in that area (for a review see Kwiatowski, Am J Hum Genet 77:171-192, 2005). For the Duffy functional role see, for example, Daniels (Vox Sanguinis 93:331-340, 2007).Duffy blood group distribution in 115 unrelated Tunisians was determined using the polymerase chain reaction with sequence specific primer (PCR-SSP) method detecting the five allelic versions of the FY gene. The red cell antigenic FY phenotype, for each donor, was deduced through DNA analysis. The blood samples of the positive FY*X alleles were investigated by serological methods, mainly the fixation-elution technique.The following allele frequencies were found (after having excluded FY*X, which had frequency of 0.0174): FY*1 = 0.291 (expressed 0.260; silent 0.031); FY*2 = 0.709 (expressed 0.427; silent 0.282). The most surprising result in this work is the detection of the FY*1 silent allele, usually quite rare, in four samples (1.74%). For FY*2 silent, the predominant allele in Africans, genotyping results showed a prevalence of 29.57%. The FY locus was in Hardy-Weinberg equilibrium in the present sample.When compared with European and African data, Tunisian samples demonstrated the presence of the common signs of these two ancestries (FY*2 and FY*X for the first population; and FY*2 silent for the last one). These data confirm the mixed roots of this urban Tunisian population already suggested by numerous studies on other haematological markers.

Long-storage tomato landraces are niche crops traditionally cultivated in southern Italy for drought tolerance and high nutritional and organoleptic quality of fruits. Nowadays, there is a growing interest in these crops as for exploiting biodiversity and the "Made in Italy" food production. We studied the physiological and biochemical performances of two landraces in response to soil water deficiency and re-watering. The potted-plant experiments were carried out in greenhouse during 2012 and 2013. During the first year, an intense water stress determined a decrease of stomatal conductance (gs) and net CO2 assimilation (A) along with an increase in both proline and ABA content, without any effect on photochemistry. In the second year, a more severe water stress leaded to a greater decline of both gs and A, and a reduction in photochemistry. During the re-watering, the full recover of gas exchanges and photochemistry, indicated the occurrence of efficient stomatal control and photochemical regulation, rather than impairment of photosynthetic apparatus. The activity of poly ADP-ribose polymerase (PARP), a key regulator of the energy homeostasis during stress conditions, showed during the first cycle of stress an evident increase, followed by a decrease. Re-watering, instead, produced a new non-expected increase of activity, which returned to control values during the second cycle of water stress. The two tomato landraces succeeded to cope with water stress by a useful synergy of biochemical and physiological regulatory mechanisms. This work was financially supported by "CISIA for the Made in Italy" Project of the National Research Council of Italy.

The frequencies of HLA class I and class II alleles and haplotypes of 104 healthy unrelated Tunisians were analyzed by high-resolution PCR-reverse dot blot hybridization, and was compared with other Mediterranean and Sub-Saharan Africans using genetic distances measurements, Neighbor-joining dendrograms, correspondence, and extended haplotypes analysis. The most frequent HLA class I A alleles were A*02, A*24, and A*30, while the most frequent B alleles were B*44, followed by B*50, B*51, and B*07. Among HLA class II DRB alleles analyzed, the most frequent were DRB1*0301, DRB1*0701, DRB1*1501, followed by DRB1*1303 and DRB1*0102; for DQB1, they were DQB1*0301 and DQB1*0201. Three-locus haplotype analysis revealed that A*03-B*07-DRB1*1503 and A*02-B*44-DRB1*0402 were the most common HLA class I and II haplotypes in this population. Compared with other communities, our result indicate that Tunisians are very related to North Africans and Western Europeans, particularly Iberians, and that Tunisians, Algerians, and Moroccans are close to Berbers suggesting little genetic contribution of Arabs who populated the area in 7th to 8th century AD. The similarities and differences between Tunisians and neighboring and related communities in HLA genotype distribution provide basic information for further studies of the MHC heterogeneity among Mediterranean and North African countries, and as reference for further anthropological studies.

Resume Justification La constatation d'une candidurie est de plus en plus frequente chez les patients hospitalises en reanimation mais sa signification diagnostique est encore controversee. Objectifs Preciser l'interet de la numeration des levures dans les urines et rechercher une eventuelle correlation entre l'importance de la candidurie, l'indice de colonisation et les facteurs de risque d'une candidose invasive. Type d'etude Etude prospective. Patients et methodes Etude realisee chez 162 patients hospitalises durant plus de 72 heures au service de reanimation sur une periode de quatre mois. La recherche de Candida dans les urines a ete effectuee une fois par semaine, associee a des prelevements au niveau d'autres sites permettant le calcul de l'index de colonisation de Pittet. Resultats La candidurie a ete decelee chez 56 patients (34 %). Elle etait superieure ou egale a 104 UFC/ml chez 28 patients (50 %). Candida tropicalis a ete isolee dans 41 % des cas, Candida glabrata (22 %), Candida albicans (20 %). Tous les patients avaient plusieurs facteurs de risque de candidose invasive associes. Six patients (10 %) ont developpe une candidose invasive. La mortalite a ete de 52 %. L'index de colonisation de Pittet a differe significativement entre les malades ayant une candidurie isolee et ceux presentant une candidose invasive (p = 0,01). De meme, un index superieur a 0,5 a represente le seul facteur significativement associe a une candidurie superieure ou egale a 104 UFC/ml. Conclusion La constatation d'une candidurie superieure ou egale a 104 UFC/ml associee a des facteurs de risque pourrait constituer un facteur predictif d'une eventuelle invasion candidosique.

L'etude de la dynamique d'une structure de forage est proposee en torsion. Les instabilites de torsion, generalement connues sous le nom de stick-slip, peuvent conditionner toute une phase de forage et reduisent les performances du systeme. Des mesures des parametres a l'outil sont obtenues a l'aide d'un outil instrumente. Deux plages de fonctionnement sont mises en evidence experimentalement, confortees par un modele de poutre. En fonctionnement dit stationnaire ou desire, le systeme dynamique est lineaire et l'analyse modale decrit fidelement la phenomenologie. Une perturbation des parametres structuraux (generalement les parametres operatoires) fait bifurquer le systeme vers un attracteur periodique, caracteristique du stick-slip. Une non linearite ponctuelle apparait en effet, justifiee par des considerations portant sur l'interaction outil-roche. Cette bifurcation est theoriquement apprehendee a partir d'une analyse linearisee et experimentalement mise en evidence.

The phase change possibilities in the surface phase formed in a binary liquid system (water 2,5dimethylpyridine) in contact with a solid (silica) have been examined on the basis of adsorption isotherms determined at ten different temperatures. The liquid mixture undergoes a liquid–liquid demixing but also, some 20° below the critical point, a solid phase separation. On the l.h.s. of a liquid–liquid coexistence curve 2,5dimethylpyridine, diluted in water, adsorbs step by step, and on the r.h.s. the relative adsorption is wave shaped. Both behaviors can be explained by a layering process, i.e., a solid–liquid surface demixing, which unexpectedly does not exclude a separate liquid–liquid surface demixing, which could constitute the prewetting process. This analysis is compared with known theories and its consistency is carefully checked on a thermodynamical basis.

Pneumocystosis is a common opportunistic infection in immunocompromised patients, especially in AIDS patients. The diagnosis of this pneumonia has presented several difficulties due to the low sensitivity of conventional staining methods and the absence of culture system for Pneumocystis. The molecular biology techniques, especially the PCR, have improved the detection of DNA of this fungus in invasive and noninvasive samples, and in the environment which highlighted human transmission and the existence of environmental source of Pneumocystis. In addition, various molecular biology techniques were used for typing of Pneumocystis strains, especially P. jirovecii, which is characterized by a significant genetic biodiversity. Finally, the widespread use of cotrimoxazole for the treatment and prophylaxis of pneumocystosis has raised questions about possible resistance to sulfa drugs in P. jirovecii.

The genus Fusarium, initially known for its important agro-economic impact, is more and more often implicated in human pathology. In fact, multiples allergic, toxic and infectious manifestations are more reported in immunocompetent and immunocompromised hosts. The objective of our study was to analyse the epidemiological, mycological and clinical features of fusariosis reported in our CHU. Eighty-seven cases of Fusarium infections were collected: 34 cases of onychomycosis (39%), 26 cases of intertrigos (30%), 25 cases of keratomycosis (29%), one case of atypical invasive fusariosis due to Fusarium oxysporum species complex (FOSC) and one case of localized gingivolabial fusariosis due to Fusarium solani species complex (FSSC) in a patient with leukemia in phase of deep bone marrow aplasia, whose outcome was favorable after exiting of aplasia period and a treatment by amphotericine B. The case of pseudotumoral cutaneous fusariosis to F. oxysporum complicated with osteolysis and septic arthritis occurred in a pregnant woman without any immune deficit. The evolution was fatal in spite of prescription of multiple systemic antifungals. Concerning keratomycosis, Fusarium was the first agent responsible for these infections (43%). The corneal traumatism was found in 37.5% of cases and FSSC was the most isolated (72%). For superficial dermatomycosis, Fusarium was the third agent of onychomycosis in molds (25%). The most isolated species were FSSC (68%) and FOSC (20%). The intertrigo frequency was 0.07% and they were mostly caused by FSSC (84%) and FOSC (16%). Fusarium is an important cause of mold infections in our region. So, the species identification is useful because some species are resistant to the most common systemic antifungal agents.

Acanthamoeba keratitis (AK) is a sight-threatening infection. We report five cases of AK diagnosed from 2005 to 2009 in the Laboratory of Parasitology-Mycology at Habib Bourguiba Sfax Hospital, Tunisia. All were associated with improper care of contact lenses (rinsing of contact lenses with tap water and inappropriate cleaning) and lens storage. The patients displayed different clinical presentations: corneal inflammation, corneal ulceration, and corneal abscess. The diagnosis was made after direct examination, culture, and polymerase chain reaction amplification with specific primers. The genotype classification was based on the highly variable DF3 region in the 18S rRNA gene. This is the first study characterizing Acanthamoeba genotype in Tunisia and North Africa. All Acanthamoeba isolates were associated to the T4 genotype. Three different DF3 sequence types were related to AK infections T4/10, T4/15, and T4/16.

Trichophyton verrucosum is a zoophilic dermatophyte. It can be responsible of various clinical aspects especially inflammatory lesions of skin and scalp. The aim of this study was to determine the clinical and epidemiological characteristics of dermatophytosis due to T. verrucosum.It is a retrospective study realized on 35,918 patients suspected to have superficial mycoses in a 13-year-period (from 1998 to 2010).T. verrucosum was isolated in 178 patients corresponding to 1.2% of all dermatophytosis. Ochraceum variety was the most frequent (60%), followed by album variety (40%). Frequency of isolated T. verrucosum increased passing from one case in 1998 to 37 cases in 2010. The mean age was 22.7 years (range: 1.5-71 years). A percentage of 74.2 of our patients were male and 61% were from urban regions. A percentage of 32.5 could link their clinical lesions to contact with an animal (mainly cattle and sheep). Other family members were infected by tinea in 7.3% of cases. Tinea corporis was the most frequent (62.2%), followed by tinea capitis (31.6%). Ten cases of sycosis, one case of tinea pedis and one case of pubic tinea were diagnosed. Lesions of skin were erythemato-squamous (82.5%) and pustulo-inflammatory (17.5%), affecting mainly upper limb (58.3%) and face (25.8%). For tinea capitis, lesions were squamous (30.8%) and pustulo-inflammatory (41%). Eleven cases of kerion celsi were diagnosed (28.2%). Patients were affected in one site (79.7%), two sites (16.9%) and three or more (3.4%).Dermatophytosis due to T. verrucosum is in recrudescence in our region. This finding may be explained by changing behaviors and activities of the population with a low socioeconomic level who kept a larger number of domestic animals at homes.

Vulvovaginal candidosis (VVC) is a common infection of the female genital tract affecting 75% women at least once in their lifetime. The aim of this study was to determine the incidence and potential risk factors associated with VVC and recurrent vulvovaginal candidosis (RVVC). A prospective study of women with vaginitis symptoms was conducted over 2 years in the regional clinic of population and family education in Sfax. A discriminant analysis was used to evaluate the association between the incidence of Candida vaginitis and potential risk factors. Sporadic and recurrent VVC were documented respectively in 48% and 6.1%. The most frequent factors associated with positive Candida culture were employed women, uncontrolled diabetes, history of genital infection and intrauterine device contraception. Increased episode numbers of VVC and condom/spermicidal contraception were positively associated with recurrences. Candida albicans was the predominantly isolated species (76.3%) followed by Candida glabrata (19.3%). Infection with C. glabrata occurred in 34% and 17.5% of patients with RVVC and VVC respectively. The discriminant investigation had provided further insights into the basis for prevention and control of RVVC. Increased prevalence of C. glabrata in patients with RVVC and observed risk factors should be taken into consideration to achieve success in the management of this infection.

Demodicidosis is an ectoparasitosis, common to humans and many mammals. It is caused by the proliferation of a mite Demodex sp in the pilosebaceous follicles. Its pathogenic role remains controversial. The aim of our study was to report epidemiological and clinical particularities of cases of demodicidosis diagnosed in our region. Over a period of nine years (January 2000 to December 2008), 427 cases of demodicidosis were diagnosed. 73.2% of cases were blepharitis and 26.8% of cases were facial dermatosis. The mean age was 44 years. Women were slightly more affected (56%) than men. Among 787 chronic blepharitis, 243 cases were due to Demodex sp (30.9%). They were treated with yellow oxide of mercury (Ophtergine® 1%). In the face, this mite has been isolated from erythematous and pruritic papulopustular lesions, and their distribution was as follows: cheeks (22.1%), forehead (13.4%), and nose (11.5%). The diagnosis was confirmed by parasitological examination of scales showing more than 5 Demodex sp/cm(2) and response to treatment with metronidazole (Flagyl®) for three months. Currently, there were a large number of arguments for the incrimination of Demodex sp in pathogenesis of dermatosis and blepharitis. Dermatologists and ophthalmologists must therefore think to this mite. The density of Demodex sp found by parasitological exam is a determining factor in establishing an anti-Demodex treatment whose effectiveness is a further argument for the diagnosis.

Candida glabrata has emerged as a common cause of fungal infection causing mucosal and systemic infections. This yeast is of concern because of its reduced antifungal susceptibility to azole antifungals such as fluconazole. A clear understanding of the epidemiology of Candida infection and colonisation required a reliable typing system for the evaluation of strain relatedness. In this study, we discuss the different molecular approaches for typing C. glabrata isolates. Recent advances in the use of molecular biology-based techniques have enabled investigators to develop typing systems with greater sensitivities. Several molecular genotypic approaches have been developed for fast and accurate identification of C. glabrata in vitro. These techniques have been widely used to study diverse aspects such as nosocomial transmission. Molecular typing of C. glabrata could also provide information on strain variation, such as microvariation and microevolution.

Invasive aspergillosis (IA) is a major opportunistic infection in haematology patients. Preventive measures are important to control IA because diagnosis is difficult and the outcome of treatment is poor. We prospectively examined the environmental contamination by Aspergillus and other fungal species and evaluated the prevalence of invasive aspergillosis in the protect unit of haematology. A three-year prospective study (December 2004-September 2007) was carried out in the department of haematology of Hedi Chaker Hospital. Suspected invasive aspergillosis cases were reviewed and classified as proven, probable and possible invasive aspergillosis using the EORTC criteria. During the study period, we collected weekly environmental samples (patient's rooms, tables and acclimatisers) and clinical samples from each patient (nasal, expectoration and auricular). Among 105 neutropenic patients, 16 had probable and 13 had possible IA. A total of 1680 clinical samples were collected and A. flavus was most frequently isolated (79.2%). Analysis of 690 environmental samples revealed that Penicillium (44%) was the most frequent followed by Cladosporium (20%), Aspergillus spp. (18%) and Alternaria (13%). The PCR-sequencing of 30 A. flavus isolates detected from clinical and environmental samples confirmed the mycological identification. Our findings underline the importance of environmental surveillance and strict application of preventive measures.

The frequency of toxoplasmosis depends on life-style and environment. Our objective was to study different epidemiological, clinical and biological aspects of toxoplasmosis in the Sfax area (Tunisia). This retrospective study has been performed on seria of 40,566 pregnant women in the Parasitology-Mycology Laboratory of Habib-Bourguiba Sfax hospital-Tunisia for 13 years from 1994 to 2006; 1,691 patients presenting with lymphadenopathy; 191 immunocompromised patients (78 HIV infected patients and 113 transplanted patients) and 21 patients presenting clinical signs of ocular toxoplasmosis. In pregnant women, the seroprevalence was 39.3% (15,952/40,567). Among 24,089 seronegative women, only 6,890 (28.6%) had been followed up during their pregnancy. An active toxoplasmosis possibly acquired during pregnancy was detected in 1.3% of cases. Sixteen congenital toxoplasmosis were detected. Toxoplasmosis was confirmed in 13.7% of the 169 patients with lymphadenitis. For HIV positive patients, 11.7% had cerebral toxoplasmosis. It revealed the HIV infection in four cases. Among transplant recipients, one case of active toxoplasmosis was diagnosed in a renal transplant recipient who received transplant from a seronegative donor. Twenty-one patients presenting toxoplasmic retinochoroiditis were treated by subconjonctival injections of clindamycin and systemic corticotherapy at a dose of 1 mg/kg per day. This clinical toxoplasmosis diversity explains the need for bioclinical confrontation to establish diagnosis.

Candida dubliniensis was recently described (1995) associated with oral candidiasis in HIV-positive patients. This organism is very closely related to the pathogenic human yeast, Candida albicans, and share a great number of phenotypic and genotypic characters. This great similarity limits the discrimination between these two species. Several phenotypic and molecular methods were developed. The phenotypic methods are simply used in routine discrimination between these two species and depend on the growth at high temperature, sugar assimilation, growth on special mediums and chlamydospore production…; but these methods are insensitive in discrimination between these two species. The molecular biology methods are highly reliable and able to confirm rapidly the identification of this species. In this article, we will review the various studies run out concerning the methods deployed for the identification of C. dubliniensis as well as the epidemiological implication of this new pathogen.

The aim of this study is to evaluate the contribution of the immunoWesternblot for the diagnosis and the post surgical follow-up of the hydatidosis. 71 sera from patients with hydatidosis confirmed by surgery were studied. All had a negative hydatic serology by screening tests (enzyme-linked immunosorbent assay, hemagglutination, electrosyneresis). 12 patients with sera in pre and post operative were monitored for 2 years. The Echinococcus Western blot IgG permitted to rectify the diagnosis of hydatidosis in 67.6 %. The rate of positivity was 100 % for the multivesicular liver cysts, 60 % for the young cysts and 50 % for the calcified cysts. Western blot permitted to rectify the diagnosis of lung cysts in 62.5 % of cases and in 50 % of cranial-spinal localizations. Analysis of Western Blot evolution in the 12 patients followed in pre and post-surgical revealed the disappearance of the bands 16, 18 and 26-28kDa in 8 month in the 8 patients with complete exeresis. This study proved the value added of Western blot compared to the other traditional techniques for the immunodiagnostic and the post-surgical monitoring of hydatidosis.

Introduction Trichophyton verrucosum est un dermatophyte zoophile cosmopolite responsable chez l’homme de divers aspects cliniques notamment de lesions inflammatoires agressives de la peau et des teignes inflammatoires. L’objectif de notre etude etait d’etudier les caracteristiques cliniques, epidemiologiques et mycologiques des dermatophyties a T. verrucosum . Patients et methodes Il s’agit d’une etude retrospective portant sur 45 513 patients suspects de dermatomycoses adresses au laboratoire de parasitologie-mycologie du CHU Habib Bourguiba de Sfax, durant une periode de 16 ans (de 1998 a 2013). Nous avons realise aussi une etude moleculaire de 36 souches identifiees morphologiquement comme T. verrucosum et appartenant a 34 patients differents. Cette etude moleculaire comportait une PCR-RFLP et une PCR-sequencage. Nous avons amplifie les regions ITS a l’aide de deux amorces universelles ITS1 et ITS4. Les enzymes utilisees etaient HinfI et MvaI. Resultats Parmi ces 45 513 patients, 19620 presentaient une dermatophytose. T. verrucosum etait isole chez 238 patients (1,21 %) correspondant a 281 prelevements positifs. L’âge moyen etait de 32,2 ans avec des extremes allant de 16 mois a 84 ans. Le sex-ratio etait de 2,5. Nos patients etaient d’origine urbaine dans 61 %. La notion de contact avec les animaux a ete trouvee chez 29,4 % de nos patients. Les animaux les plus incrimines a l’origine de la contamination etaient les bovins (29,6 %) et les ovins (24,6 %). Les atteintes etaient plus frequentes en hiver (42 %) et en printemps (32,3 %). La forme clinique la plus frequente etait la dermatophytie circinee (61,5 %) suivie par les teignes du cuir chevelu (30,3 %). L’examen mycologique identifiait T. verrucosum var album dans 80 % des cas et T. verrucosum var ochraceum dans 20 %. Apres amplification par PCR, nous avons obtenu des bandes de 684 pb, 678 pb et de 710 pb. La digestion par HinfI a genere 4 profils : A, B, C et D. La digestion par MvaI a donne 3 profils : I, II et III. Le sequencage a donne 2 types de sequences de T. verrucosum (sequence I et sequence II). Le premier genotype qui etait predominant dans notre etude (93,75 %) correspondait a un genotype de T. verrucosum peu decrit dans la litterature. Discussion L’incidence des dermatophytoses a T. verrucosum est en augmentation dans notre pays. Ainsi, l’etude epidemiologique est un outil essentiel pour developper des strategies de lutte contre ce dermatophyte. L’etude moleculaire a permis non seulement de resoudre rapidement les difficultes d’identification morphologique de T. verrucosum surtout avec T. violaceum variete glabrum mais aussi de detecter le polymorphisme au sein de cette meme espece. Conclusion L’identification precise de T. verrucosum est importante non seulement pour un diagnostic precis mais surtout pour cerner l’origine de la contamination et par consequent, pour un meilleur traitement curatif et preventif.

Le gene NOD2/CARD15 code pour une proteine qui appartient a la famille des recepteurs de l’immunite innee. Elle porte 4 domaines. Un domaine fait de repetition de zones riches en leucine permet l’interaction avec des composants bacteriens dont le lipopolysaccharide (LPS). Un domaine liant les nucleotides (NBD) permet l’oligomerisation de la proteine. Enfin, deux domaines Caspase recruitment domain (CARD) servent d’effecteurs en permettant une liaison a d’autres proteines activant l’apoptose et la voie de NF-kB. La proteine NOD2 est exprimee par les cellules des epitheliums digestif et pulmonaire. Des mutations au niveau de ce gene, alterant la fonction de NOD2 ont ete decrites ; celles situees dans la region LRR, qui sont des polymorphismes de type SNP : SNP 8 (Arg702Trp), 12 (Gly908Arg) et 13 (Leu1007fsinsC). Ces polymorphismes, responsables d’une modification de la reponse inflammatoire et de la defense anti-infectieuse, ont egalement ete impliques dans certaines complications apres allogreffe de cellules souches hematopoietiques(CSH). On s’est propose dans notre travail, d’etudier les frequences du polymorphisme de type SNP12 (Gly908Arg) dans la population des greffes de moelle osseuse, par la technique de PCR-SSP. Pour cela on a determine les frequences alleliques et genotypiques du SNP12 chez 120 couples donneur/receveur. Nos resultats sont proches de ceux rapportes dans la population europeenne. Les resultats de cette etude serviront de base pour les etudes d’association avec la survenue de certaines complications post-greffe (la bronchiolite obliterante) chez les Tunisiens greffes de CSH.

Candiduria is increasingly frequent among patients admitted to intensive care units but its significance remains unclear.Search for eventual correlation between quantitative candiduria and known risk factors for invasive candidiasis.Prospective.A four-month study was conducted in 162 patients hospitalized in the intensive care unit for more than 72 hours. All patients underwent a weekly research of candiduria added to sampling from different body sites to determine the Pittet Candida colonization index.Candiduria has been proved in 56 cases (34%). It was superior or equal to 10(4) UFC/ml among 28 patients (50%). Candida tropicalis, Candida glabrata and Candida albicans has been isolated in 41, 22 and 20% respectively. All patients had at least one major and two minor risk factors for Candida infection. Six patients (10%) developed invasive candidiasis. The global mortality rate was at 52%. Pittet colonization index was significantly different between patients with candiduria and those with invasive candidiasis (p=0.01). There was a statistically significant correlation between candiduria superior or equal to 10(4) UFC/ml and Pittet colonization index superior or equal to 0.5 (p=0.01).Candiduria superior or equal to 10(4) UFC/ml associated with risk factors may predict invasive candidiasis in critically ill patients.

SummaryWith the emergence of rotary steerable systems (RSSs), the technical issue concerning bit design for a specific directional application has reappeared. Today, a bit must be specifically designed for use with a particular directional system: rotary bottomhole assembly (BHA), steerable mud motor, or RSS. The reason is that the bit must have the ability to respond properly and rapidly to a side force applied by the steering system to initiate a deviation. To do so, the bit must have a predetermined steerability compatible with the directional system to provide the optimum dogleg potential.The new generation of directional-drilling systems differentiates "pointing the bit" from "pushing the bit." As a consequence, the bit's directional response is a key factor that operators and directional drillers need to know to make a good adaptation between the bit and the BHA. However, at the moment there is no standard method for classifying bits by steerability and walking tendency.On the basis of a comprehensive analysis of the directional behavior of polycrystalline diamond compact (PDC) bits (numerical simulation and pilot and field tests), a simple methodology has been developed that defines and evaluates their steerability and walking tendency. This methodology is used to classify the PDC bits defined with their IADC bit profile codes.Because PDC bit steerability is mainly a function of the bit profile, the gauge cutters, and the gauge pad, some design recommendations are given concerning these three parts. For each IADC bit profile code, the bit steerability and walking tendency are estimated through some formulas linking only the heights and lengths of the cutting profile. Some guidelines are also given about the gauge-pad length and gauge-cutter characteristics to achieve improved steerability.This simple method based on geometrical criteria allows quick estimation of not only the PDC bit steerability but also the maximum dogleg potential achievable by the bit when it is coupled with the steering system.

Echinococcosis is one of the major parasitic diseases in Tunisia, accounting for a considerable public health problem. We propose in this work to analyse the behaviour of butchers and to evaluate its impact on the hydatic cyst transmission.We carried out a national transversal descriptive survey that included 97 butcher shops using illegal practice, located in 18 regions (governorats) of Tunisia. The sampling procedure was implemented according to the level of disease endemicity.60.8% of butcher shops were located along main roads and therefore supplying travellers. Among the animals slaughtered sheep come in first position (97.9%). More than 80% of the butchers kept aside a place around the butcher shop to sacrifice their animals. We noted the presence of dogs near butcher shop in 52.6% of cases and stray dogs in 43.3% of cases. Only 13.4% of the butchers knew the disease mode of transmission. Parasitized viscera were thrown into dustbins or further in the riverbed in 56.7%. More than 50% of butchers, having an inadequate behaviour in front of parasitized viscera or ignoring the disease cycle, were originating from an hyper or holoendemic area.Illegal slaughtering practices have an important impact on transmission of cystic echinococcosis in Tunisia.

A retrospective study of strongyloidiasis cases was carried out in Sfax University (Tunisia), between 1989 and June 2001. Diagnosis was done by direct stool examination, concentration methods, Baermann larval extraction and fecal culture. Strongyloidiasis was diagnosed in 27 patients of whom 77% were males living in rural areas under low socioeconomic level. Mean age of patients was 47 years (8 to 85 years). Hypereosinophilia was present in 75 % of cases, and 7 patients were treated by systemic corticosteroids. So, it is important to detect this parasite by repeated parasitological stool examinations, particularly before a long corticosteroid treatment.

Between January 1995 and December 2000, 512 cases with mycologically confirmed tinea capitis have been diagnosed in our laboratory. In addition, finger nail samples have been taken from 211 patients out of 512. The culture of the nail samples taken was positive for 80 patients (38%). The isolated dermatophytes were the same in the nails and the scalp. Microsporum canis was isolated in 82% of nail samples. Trichophyton violaceum grew only in 18% and Trichophyton quinckeanum in one case. A T. violaceum onychomycosis was found in two patients with tinea capitis. Twenty-one cases of tinea were resistant to 6 weeks treatment with griseofulvin. Thirty per cent of them have had fungal elements in nails. Dermatophyte colonization of the nails in tinea patients could be a factor of tinea capitis transmission and could explain some recurrent tinea capitis cases and therapy resistance.

A case of inflammatory tinea capitis caused by Trichophyton mentagrophytes var. quinckeanum in a 3-year-old Tunisian girl is presented. The disease healed after treatment with griseofulvin for 6 weeks and topical application of econazole.

Summary The importance of wellbore deviation is well recognized by the drilling industry. An analysis of a drilling system's directional behavior must include the directional characteristics of the drill bit. This paper presents a comprehensive analysis of the directional behavior of polycrystalline diamond compact (PDC) bits, including the effect of bit profile, gauge cutters, and gauge length. Numerical simulations as well as laboratory tests have been carried out to better understand the mechanisms of PDC bit deviation and to evaluate the most important parameters affecting the directional behavior of PDC bits. The analysis presented in this paper shows that each part of the PDC bit (profile and active and passive gauges) plays a major role in its walking tendency and steerability. A quantitative evaluation of how these factors contribute to well trajectory (inclination and azimuth) is given. For the first time, a full-scale directional-drilling bench was built to measure the walking tendency and steerability of PDC bits. The results obtained demonstrate that the bit profile, gauge cutters, and gauge length have a significant effect. A 3D theoretical rockbit interaction model was developed to reproduce the drilling test results.

With the emergence of rotary steerable systems, the technical issue concerning the bit design for a specific directional application has reappeared. Today, a bit must be specifically designed for use with a particular directional system: rotary bottom hole assembly (BHA), steerable mud motor or rotary steerable system (RSS). The reason is that the bit must have the ability to respond properly and rapidly to a side force applied by the steering system in order to initiate a deviation as requested. To do so, the bit must have a predetermined steerability compatible with the directional system in order to provide the optimum dog leg potential. The new generation of directional drilling systems differentiates "pointing the bit" from "pushing the bit". As a consequence, the bit directional response is a key factor that operators and directional drillers need to know to make the good adaptation between the bit and the BHA. However at the moment, there is no standard method that can propose a way to classify bits according to their steerability and walking tendency. Based on a comprehensive analysis of the directional behavior of polycrystalline diamond compact (PDC) bits (numerical simulation, pilot and field tests), a simple methodology has been developed in order to define and evaluate the steerability and the walking tendency of PDC bits. This methodology is used to classify the PDC bits defined with their IADC bit profile codes. As the PDC bit steerability is mainly a function of the bit profile, the gage cutters and the gage pad, some design recommendations are given concerning these three parts. For each IADC bit profile code, the bit steerability and the walking tendency is estimated through some formulas linking only the heights and lengths of the cutting profile. Some guidelines are also given about the gage pad length and gage cutters characteristics in order to achieve improved steerability. This simple method based on geometrical criteria enables to estimate quickly not only the PDC bit steerability, but also the maximum dog leg potential achievable by the PDC bit, when coupled with the steering system.

This paper proposes and evaluates an approach for partitioning and mapping a class of parallel discrete event simulation models. The class of models is a subset of Petri Nets known as marked graphs. Six commercial simulation models based on the marked graph modeling paradigm are examined to evaluate the available parallelism typically found in real models. The parallelism that can be exploited is very dependent upon effective partitioning and mapping algorithms to ensure a useful distribution of concurrently executable events. A partitioning and mapping algorithm is proposed in this paper, and its performance is evaluated. >

This paper describes and evaluates the performance of an implementation of a parallel discrete event simulation of a class of Petri nets known as marked graphs on a single instruction stream multiple data stream (SIMD) architecture. The implementation uses an efficient, novel memory management technique for supporting abstract data types, where memory can be dynamically allocated/deallocated on an individual PE basis. Performance evaluations are reported for a number of "real world" applications. >