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Keskes S.,University of Carthage | Keskes S.,French National Institute for Agricultural Research | Hmaied F.,Laboratoire Of Microbiologie Et Biologie Moleculaire | Gannoun H.,University of Carthage | And 3 more authors.
Bioresource Technology | Year: 2012

The performance of a submerged membrane bioreactor (SMBR) has been investigated for abattoir wastewater (AW) treatment. The chemical oxygen demand (COD) of permeate has not exceeded 25mgL -1 providing an average COD removal of 98%. Microbiological analysis showed that the SMBR has allowed a complete removal of fecal coliforms, Listeria and Salmonella. A significant reduction in the excess biomass production was also observed. In fact, the yield of biomass production (Yobs) ranged between 0 and 0.106g suspended solids/g COD removed.The study of the dynamic of bacterial communities using the single strand conformation polymorphism (SSCP) method showed a significant change in the population structure and revealed a correlation between the sludge production yield and the bacterial communities. © 2011 Elsevier Ltd. Source


Elbeldi A.,Laboratoire Of Microbiologie | Elbeldi A.,Institute Pasteur Of Tunis | Smaoui H.,Laboratoire Of Microbiologie | Hamouda S.,Laboratoire Of Microbiologie | And 8 more authors.
Bulletin de la Societe de Pathologie Exotique | Year: 2011

Listeria monocytogenesis a Gram positive facultative intracellular bacterium that can be responsible for severe infections, affecting essentially pregnant women, immunocompromised patients at the early and later stages of life. In Tunisia, invasive L. monocytogenes infections are thought to be exceptional and limited data are available about listeriosis. We reported seven cases (five newborn children and two infants) of human listeriosis that occurred in Tunis from 2000 to 2008. The newborn children were hospitalized for suspicion of maternofoetal infections. The two infants were hospitalized for fever associated with digestive signs in one case and neurological signs in the other. L. monocytogeneswas isolated from culture of cerebrospinal fluid in four cases, peripheral samples in two cases and from blood culture in one case. Isolates identification was based on conventional methods. Antimicrobial susceptibility was realized according to the recommendation of the "Comité de l'antibiogramme de la Société française de microbiologie". All L. monocytogenes isolates were sensitive to amoxicillin and aminoside but resistant to 3rd generation cephalosporins. Investigations of the immune system were realized for the two infants including phenotypic analysis of peripheral blood cells by flow cytometry, lymphocyte proliferation assays, phagocytic cell functions and measurement of immunoglobulins as well as complement. All these explorations were normal for both infants. The outcome was fatal in only one case (a newborn child), and all the other patients recovered after adapted antibiotic treatment. In conclusion, our study shows that listeriosis is not exceptional in Tunis. Thus, it is necessary to know how to evoke this diagnosis, at any age, in order to establish an early and adapted antibiotic treatment and to avoid fatal outcome. © Société de pathologie exotique et Springer-Verlag France 2010. Source


Amri I.,Laboratoire Of Microbiologie Et Biologie Moleculaire | Hmaied F.,Laboratoire Of Microbiologie Et Biologie Moleculaire | Loisy F.,Center Europeen Dexpertise Et Of Recherche Sur Les Agents Microbiens | Lebeau B.,Center Europeen Dexpertise Et Of Recherche Sur Les Agents Microbiens | And 3 more authors.
Pathologie Biologie | Year: 2011

Objectives: We aimed at evaluating the contamination by hepatitis A virus (HAV) of 54 shellfish samples collected from five Tunisian shellfish harvesting areas and finding a correlation between bacterial and viral contamination. Material and methods: Fifty-four shellfish samples were analysed in our study. Two methods of viral extraction were evaluated by reverse transcription-nested PCR. The first one was based on elution by glycine solution and the second one used a beef extract solution. Bacteriological determination (Samonella and E. coli) was carried out for all shellfish samples. Results: Glycine extraction showed a higher detection rate of HAV compared to the saline beef extraction method. The hepatitis A virus was detected in 32 % of shellfish samples analysed. None of the samples revealed the presence of Samonella. From 17 samples positive for HAV, we found six samples showing a number of E. coli below the European legislation. Conclusion: An important HAV contamination was observed in our study. No correlation between bacterial and viral contamination was found. © 2009 Elsevier Masson SAS. Source


Jebri S.,Unite de Microbiologie et de Biologie Moleculaire | Jofre J.,University of Barcelona | Barkallah I.,Unite de Microbiologie et de Biologie Moleculaire | Saidi M.,Unite de Microbiologie et de Biologie Moleculaire | And 2 more authors.
Environmental Science and Pollution Research | Year: 2012

Purpose: The role of water in the transmission of infectious diseases is well defined; it may act as a reservoir of different types of pathogens. Enteric viruses can survive and persist for a long time in water, maintaining infectivity in many instances. This suggests the need to include virus detection in the evaluation of the microbiological quality of waters. Methods: In this study, enteric viruses (enteroviruses and hepatitis A virus (HAV)) were investigated by RT-PCR and coliphages (known as indicators of viral contamination) were enumerated with the double-layer technique agar in effluents and sewage sludge from three Tunisian wastewater treatment plants. Results and discussion: The molecular detection of enteric viruses revealed 7. 7% of positive activated sludge samples for enteroviruses. None of the samples was positive for HAV. Molecular virus detection threshold was estimated to be 103 PFU/100 ml. All samples contained high concentrations of coliphages except those of dry sludge. Reductions in the concentrations of bacteriophages attained by the wastewater treatment plants are of the order of magnitude as reductions described elsewhere. Peak concentrations in raw wastewater were associated with winter rains and suspended materials rate in analysed samples. Our data which is the first in North Africa showed that similar trends of coliphages distribution to other studies in other countries. Conclusion: No clear correlation between studied enteric viruses and coliphages concentration was proved. Coliphages abundance in collected samples should raise concerns about human enteric viruses transmission as these residues are reused in agricultural fields. © 2012 Springer-Verlag. Source


Hmaied F.,Laboratoire Of Microbiologie Et Biologie Moleculaire | Helel S.,Laboratoire Of Microbiologie Et Biologie Moleculaire | Le berre V.,Genopole | Francois J.-M.,Genopole | And 6 more authors.
Pathologie Biologie | Year: 2014

Objectives: We aimed at evaluating the prevalence of Listeria species isolated from food samples and characterizing food and human cases isolates. Material and methods: Between 2005 and 2007, one hundred food samples collected in the markets of Tunis were analysed in our study. Five strains of Listeria monocytogenes responsible for human listeriosis isolated in hospital of Tunis were included. Multiplex PCR serogrouping and pulsed field gel electrophoresis (PFGE) applying the enzyme AscI and ApaI were used for the characterization of isolates of L.monocytogenes. We have developed a rapid microarray-based assay to a reliable discrimination of species within the Listeria genus. Results: The prevalence of Listeria spp. in food samples was estimated at 14% by using classical biochemical identification. Two samples were assigned to L.monocytogenes and 12 to L.innocua. DNA microarray allowed unambiguous identification of Listeria species. Our results obtained by microarray-based assay were in accordance with the biochemical identification. The two food L.monocytogenes isolates were assigned to the PCR serogroup IIa (serovar 1/2a). Whereas human L.monocytogenes isolates were of PCR serogroup IVb, (serovars 4b). These isolates present a high similarity in PFGE. Food L.monocytogenes isolates were classified into two different pulsotypes. These pulsotypes were different from that of the five strains responsible for the human cases. Conclusion: We confirmed the presence of Listeria spp. in variety of food samples in Tunis. Increased food and clinical surveillance must be taken into consideration in Tunisia to identify putative infections sources. © 2013 Elsevier Masson SAS. Source

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