Fethi Ben Abdallah

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In seawater, enteric bacteria evolve toward a stressed state that is difficult to identify because of major alterations of their phenotype. In this study, we incubated four reference strains of S. enterica serovar Typhimurium in seawater microcosms for 10 months and studied the modifications of their main phenotypic characters. All of the strains lost some(More)
Vibrio parahaemolyticus and V. alginolyticus, marine foodborne pathogens, were treated with UVC-radiation (240 J/m2) to evaluate alterations in their outer membrane protein profiles. Outer membrane protein patterns of UVC-irradiated bacteria were found altered when analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Altered proteins were(More)
The marine bacteria Vibrio parahaemolyticus and V. alginolyticus were incubated in seawater for 8 months to evaluate their adaptative responses to starvation. The starved cells showed an altered biochemical and enzymatic profiles, respectively, on Api 20E and Api ZYM systems and an evolution to the filterable minicells state capable to pass membrane pore(More)
Iron uptake by transferrin from triacetohydroxamatoFe(III) (Fe(AHA)3) in the presence of bicarbonate has been investigated between pH 7 and 8.2. The protein transits from the opened apo- to the closed holoform by several steps with the accumulation of at least three kinetic intermediates. All these steps are accompanied by proton losses, probably occurring(More)
Thirty-five Staphylococcus aureus strains from auricular infections were isolated. The identification of strains was confirmed by Api ID 32 Staph strips, the antibiotic susceptibility test was performed using ATB Staph kit. PCR assay was used to detect the oxacillin resistance gene (mecA) and the erythromycin genes (ermA, ermB, ermC, msrA and mef). The(More)
The presence of the ica loci and adhesins genes in clinical Staphylococcus aureus strains were considered important factors of virulence. In this study, 46 strains of Staphylococcus aureus were isolated from auricular infection, and were investigated for slime production using Congo Red Agar method (CRA). In order to detect the adhesins genes (ica A, ica D,(More)
Salmonella enterica serovar Typhimurium was stressed by incubation in seawater and soil microcosms for 20 years. Recovery of viable but nonculturable Salmonella was obtained by incubation in nutrient broth and buffered peptone water medium for 2 months, and also in a mouse model when administered orally but not by intra-peritoneal injection. The 16S rDNA(More)
Iron loss in vitro by the iron scavenger bovine lactoferrin was investigated in acidic media in the presence of three different monoanions (NO(3)(-), Cl(-) and Br(-)) and one dianion (SO(4)(2-)). Holo and monoferric C-site lactoferrins lose iron in acidic media (pH< or =3.5) by a four-step mechanism. The first two steps describe modifications in the(More)
In this study, we investigated the pathogenic potency of twoVibrio alginolyticus strains isolated from cultured giltheadDicentrarchus labrax andSparus aurata, in Tunisia. The enzymatic activities of the extracellular products of the studied strains characterized with the API-ZYM system, revealed the existence of several activities. The 50% lethal doses(More)
In this study we investigated the morphological and biochemical changes ofSalmonella enterica serovar Agona incubated during 13 years in natural soil microcosm. After its resuscitation, the cells showed a biochemical profile completely inactive. These cells recuperated their initial characters after 6 months of incubation in Tryptic Soy broth. The scanning(More)