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Primary ciliary dyskinesia (PCD) is a clinically and genetically heterogeneous ciliopathy. Dysfunction of motile respiratory and nodal cilia results in sinopulmonary symptoms associated with laterality defects (LD) found in half of the patients. The molecular basis of the disease is insufficiently investigated in patients originating from the Arabian Peninsula. In a group of 16 unrelated Saudi patients clinically suspected of PCD and among whom only 5 (31%) had LD, we first screened by PCR-RFLP two founder mutations, RSPH9 c.804_806del and CCDC39 c.2190del previously identified in patients from the Arabian Peninsula and Tunisia, respectively. When negative, targeted panel or whole-exome sequencing was performed. Three patients were homozygous for the mutation in RSPH9, which encodes an axonemal protein that is absent from nodal cilia. None of the patients carried the CCDC39 founder mutation frequent in Tunisia. NGS analysis showed that nine patients had homozygous mutations in PCD genes. In total, sequential RFLP and NGS analysis solved 75% (12/16) of cases and identified ten distinct mutations, among which six are novel, in nine different genes. These results, which highlight the genetic heterogeneity of PCD in Saudi Arabia, show that the RSPH9 c.804_806del mutation is a prevalent mutation among Saudi patients, whereas the CCDC39 c.2190del ancestral allele is most likely related to the Berber population. This study shows that RSPH9 founder mutation first-line screening and NGS analysis is efficient for the genetic exploration of PCD in Saudi patients. The RSPH9 founder mutation accounts for the low rate of LD among Saudi patients. more...

Background and Objective: Urinary tract infections believe to be one of the main acquainted infections by Escherichia coli in hospitals with an excessive incidence of illness. This study aimed to analyze the antibiotic resistance profile and molecular characteristics of E. coli isolates recovered from patients with urinary tract infection at different hospitals in Taif Governorate, Saudi Arabia. Materials and Methods: Out of 143 isolates collected for 11 months, from February-December 2019, 24 isolates were identified as E. coli by API system and 16S rRNA sequences techniques. An antibiotic sensitivity test was performed using the disk diffusion method. Besides, the repetitive sequence repeat-PCR (Rep-PCR) technique was used for genotyping the 24 isolates. Results: Almost all isolates were resistant to most tested antibiotics such as ampicillin, ceftazidime, cefepime, trimethoprim/sulfamethoxazole, amox/clavulanic. The PCR results show that virulence genes kpsII and yaiO were detected in all E. coli isolates. Stx1, fimH, hly and uidA were moderate detected in all isolates. Conclusion: The high frequencies of antibiotic-resistant E. coli isolates in patients with urinary tract infections in the current study suggest that continuous surveillance of the use of appropriate antibiotics is required and that control of infections is necessary. more...

lt;bgt;Background and Objective:lt;/bgt; Urinary tract infections believe to be one of the main acquainted infections bylt;igt;Escherichia colilt;/igt; in hospitals with an excessive incidence of illness. This study aimed to analyze the antibiotic resistance profile and molecular characteristics oflt;igt;E. colilt;/igt; isolates recovered from patients with urinary tract infection at different hospitals in Taif Governorate, Saudi Arabia.lt;bgt;Materials and Methods:lt;/bgt; Out of 143 isolates collected for 11 months, from February-December 2019, 24 isolates were identified aslt;igt;E. colilt;/igt; by API system and 16S rRNA sequences techniques. An antibiotic sensitivity test was performed using the disk diffusion method. Besides, the repetitive sequence repeat-PCR (Rep-PCR) technique was used for genotyping the 24 isolates.lt;bgt;Results:lt;/bgt; Almost all isolates were resistant to most tested antibiotics such as ampicillin, ceftazidime, cefepime, trimethoprim/sulfamethoxazole, amox/clavulanic. The PCR results show that virulence geneslt;igt;kpsIIlt;/igt; andlt;igt;yaiOlt;/igt; were detected in alllt;igt;E. colilt;/igt; isolates.lt;igt;Stx1lt;/igt;,lt;igt;fimHlt;/igt;,lt;igt;hlylt;/igt; andlt;igt;uidAlt;/igt; were moderate detected in all isolates.lt;bgt;Conclusion:lt;/bgt; The high frequencies of antibiotic-resistantlt;igt;E. colilt;/igt; isolates in patients with urinary tract infections in the current study suggest that continuous surveillance of the use of appropriate antibiotics is required and that control of infections is necessary. more...

Escherichia coli account approximately to 85% of the Urinary tract infection. UTI affect the different parts of the urinary tract and is considered as a common bacterial infection. The infection is caused as a consequence of the urinary tract bacterial invasion. E. coli were isolated from the urine of UTI patients referred to King Abdulaziz Specialist Hospital, Taif, Saudi Arabia. Antibiotics susceptibility was tested on 25 antibiotics using the disc diffusion method. The prevalence of antibiotics resistance genes was realized by Polymerase Chain Reaction (PCR). Results showed heterogenicity in the percentage of antibiotics resistance from 100% for penicillin to 2% for imipenem. 30% of the isolates appeared as for Extended-Spectrum Beta-Lactamase (ESBL) positive and 74% are multidrug resistance strains. Distribution of antibiotic resistance genes showed that aac(3)-IV and blaSHV genes were identified in 33.33% of isolates. In addition, qnrA, blaCMY and dfrA1 genes were founded in 37.25%, 19.60% and 17.64% of the isolates respectively. In total, 17 different genotypes were detected, and 12 isolates (24%) do not include any genes in their genomes. Multi-drug resistant E. coli have antibiotics profiles highly variable and the mechanism of resistance was not correlated to the investigated genes. more...

Klebsiella pneumoniae is an opportunistic pathogen responsible for a significant proportion of nosocomial and community-acquired infections. Genotypic variation in K. pneumoniae populations is a major barrier to control public health risk associated with pathogen. In this work, thirty K. pneumoniae were recovered from hospital and were tested for their resistance to antibiotics. Genetic variability of the isolates was performed using PCR based on genes coding for porins and efflux pumps, (GTG)5 and BOX repetitive sequences. K. pneumoniae showed heterogenicity of resistance to antibiotics based on gender or specimen type. Further, out of 30 isolates, 25 different profiles were found and 83.33% are multidrug-resistant. PCR detection of genes coding for porins and efflux pumps revealed seven different genotypes and strong correlation between antibiotics resistance profiles and investigated genes. PCR genomic fingerprinting showed high genetic diversity of K. pneumoniae. BOX-PCR and (GTG)5 generated 18 and 19 clusters with discriminatory indexes 0.97 and 0.98, respectively at 80% of similarity. K. pneumoniae clinical isolates showed high phenotypic and genetic variability, and many strains can be circulating simultaneously. This genetic variability should be taken into consideration when designing strategies for controlling K. pneumoniae outbreaks. In addition, a significant correlation, was detected for the first time, between (GTG)5-genotyping and antibiotic resistance patterns of K. pneumoniae and could be valuable in the prediction of antibiotic resistance profiles of K. pneumoniae. more...

Urinary tract infections (UTIs), caused by Escherichia coli 80% to 85% of the time, are one of the most important causes of morbidity and health care spending affecting persons of all ages. These infections lead to many difficult problems, especially increasing resistance to antibiotic drugs. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. In this study, we have investigated the antibacterial activity of five medicinal plant essential oils against UTIs caused by E. coli using disc diffusion and minimal inhibition concentration (MIC) methods. In addition, biofilm inhibitory action of oils was realized by crystal violet. Gas chromatography&ndash, mass spectrometry (GC&ndash, MS) analysis showed a variability between oils in terms of compound numbers as well as their percentages. Antibacterial activity was observed only in cases of Origanum majorana, Thymus zygis and Rosmarinus officinalis, while Juniperus communis and Zingiber officinale did not showed any effect towards E. coli isolates. T. zygis essential oil demonstrated the highest antibacterial activity against E. coli isolates, followed by O. majorana and R. officinalis. Further, oils showed high biofilm inhibitory action with a percentage of inhibition that ranged from 14.94% to 94.75%. R. officinalis oil had the highest antibiofilm activity followed by T. zygis and O. majorana. Accordingly, tested oils showed very effective antibacterial and antibiofilm activities against E. coli UTIs and can be considered as good alternative for antibiotics substitution. more...

Aeromonas hydrophila strains isolated from different naturally polluted environments (ten from wastewater, six from bay used for aquaculture, eight from sea coast water and six from fish) were subjected to 13 antibiotics, and to four heavy metals (Copper, Cobalt, Zinc and Mercury) by using agar diffusion and agar dilution methods, respectively. In addition, effect of heavy metals on slime production was also investigated. Results of the antibiotic resistance agreed with those of heavy metals resistance, however, treated wastewater and bay strains were much tolerant than seawater and fish bacteria. The range of metal concentrations that was tolerated in the liquid media yielded information on the tolerance levels of A. hydrophila to different tested concentrations of metals. Copper and zinc were the best tolerated metals. Mercury was the most toxic component for all bacteria. Almost all A. hydrophila produced slime and a small number of strains have changed their morphotype under the heavy metals concentration. Our results have shown that Tunisian aquatic biotopes have a significant proportion of antibiotic and heavy metal resistant to A. hydrophila. Key words: Antibiotic resistance, Aeromonas hydrophila, heavy metals and slime producing. more...

Salmonella is an international foodborne pathogen widely disseminated in seawater that regularly causes large outbreaks of food poisoning. In this study, we have investigated the effect of starvation on the ability of Salmonella enterica serovar Typhimurium cells to adhere to polystyrene microplate and Hep2 cells in seawater microcosms after incubation for 3 years. Cell surface hydrophobicity was evaluated. Effect of stress on fatty acids composition was also established. Our results showed that after incubation in seawater, the ability of starved cells to adhere to polystyrene microplate was decreased significantly. However, the adhesion values to Hep2 cells have increased. In addition, cells surface hydrophobicity was decreased. The fatty acids composition of starved cells was modified. more...

Salmonella is an international food-borne pathogen disseminated widely in seawater that regularly causes large outbreaks of food poisoning. In this study, we investigated the effect of starvation on the survival ability of Salmonella enterica serovar Typhimurium rpoS + and its mutant rpoS – after a 6-month incubation in seawater microcosms using a colorimetric XTT assay and colony forming units (CFU). The effect of pre-adaptation in seawater and the rpoS gene on the tolerance to heavy metals of this microorganism was also investigated. Our results showed that the number of cells decreased by ∼ 5 log units for the strain rpoS + and by ∼ 5.5 log units for the mutant rpoS – after this period of stress. At the end of the experiments, cell viability was around of 20% and 10% for the wild type and mutant, respectively. We also revealed that the minimal inhibitory concentration values and cell viability under zinc, cobalt, mercury, chromium and cadmium heavy metals were decreased for the two starved strains. more...

In this study, we incubated four strains of Shigella in seawater microcosms (at room temperature and at 4°C) for eight months and we studied the alteration of their morphologic and outer membranes proteins. The starved cells showed an evolution to the filterable minicells state capable to pass membrane pore size 0.45 µm. In addition, the atomic force micrographs showed a reduction of the cells size and an evolution to coccoid-shapes. Outer membrane proteins patterns of stressed bacteria did not changed too much and these modifications were manifested by the appearance of one new band. Key words: Shigella, seawater, starvation, morphological, outer membrane proteins. more...

In this study, we incubated four strains of Staphylococcus aureus for 8 months in seawater microcosms. The biofilm formation on microplates and on glass and the surface hydrophobicity of starved cells were investigated. Our results showed that the stressed cells increased their hydrophobicity from 12 to 44% and also their capacity for producing biofilm. Indeed, after 8 months of incubation in seawater microcosms, all strains became slime positive on CRA plates and very adherent to polystyrene microplates or glass wells. more...

In this study, we investigated the survival, adhesion and the morphology of Shigella after its incubation in various concentrations of salts. Our results showed that, after 48 h of incubation, the rate of cell survival is inversely proportional to the increase of salinity of the medium. In addition to that, the results prove the evidence that the concentration of salt can significantly influence the capacity of Shigella to produce biofilm on Congo red agar and on polystyrene microplate wells. Adherence and invasion assays of Shigella were performed with KB cells line. Indeed, an increase of the salts concentration enhances the ability of Shigella species to attach and to invade the tissue culture cells. The percentage of adherence was increased to 15% and the invasion to 90% at 6% of salt. The atomic force micrographs showed a reduction of the cells’ size after stress. more...

International audience; Vibrio parahaemolyticus and Vibrio alginolyticus were subjected to γ-irradiation (0.5 kGy) or starvation by incubation for 8 months in seawater to study modifications in their outer membrane protein patterns. After treatment, outer membrane protein profiles of starved or γ-irradiated bacteria were found to be altered when analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Altered proteins were identified by mass spectrometry (MS and MS/MS) and analyses revealed that OmpU can be considered a starvation stress-induced protein. In addition, expression of OtnA, OmpW, OmpA and peptidoglycan-associated lipoprotein decreased to non-detectable levels in starved cells. Furthermore, MltA-interacting protein MipA appeared under γ-irradiation or starvation conditions. Thus, it can be considered to be a γ-irradiation, long-term starvation stress protein in some vibrios. more...

The survival of bacteria in natural environments is of practical importance. In this study, we investigated the effect of starvation on the survival and adhesion ability of Shigella in domestic treatment plant effluent microcosms after incubation at either room temperature or 4°C for 1 month. Our results showed that the number of cells decreased considerably after this period of stress. We also revealed some modifications to the biochemical and enzymatic profiles, and antibiotic susceptibility of stressed cells. Adherence assays to the human oral cavity epidermoid carcinoma (KB) cell line revealed an increase in the number of adherent cells from 0.7 to 1.85% after 1 month of incubation in domestic treatment plant effluent. 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 gene sequences from 20-year stressed strains were homologous, with a high degree of similarity, and all were identical to the respective initial strain. more...

Gamma-irradiation technology sterilizes microorganisms and thereby prevents decay and improves the safety and shelf stability of food products. In this study we treated the foodborne pathogens Vibrio parahaemolyticus and Vibrio alginolyticus with gamma-irradiation (0.5 kGy) to evaluate their adaptative response. Outer membrane protein patterns of irradiated bacteria were found altered when analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. These modifications were manifested by the appearance and/or disappearance of bands as well as in the expression level of certain proteins. In addition, we searched for the presence of eight Vibrio cholerae virulence genes, toxR, toxS, toxRS, ctxA, zot, ace, toxT, and virulence pathogenicity island (VPI), in the genome of investigated strains. The expression of toxR, toxS, VPI, and ace genes in gamma-irradiated bacteria, studied by reverse transcriptase polymerase chain reaction, was altered. These variations were manifested by an increase and/or a decrease in the expression level of tested virulence genes. more...

In this study we investigated the phenotypic slime production of Vibrio alginolyticus and Vibrio parahaemolyticus strains, food-borne pathogens, using a Congo red agar plate assay. Furthermore, we studied their ability to adhere to abiotic surfaces and Vero cells line. Our results showed that only V. alginolyticus ATCC 17749 was a slime-producer developing almost black colonies on Congo red agar plate. Adherence to glace tube showed that all V. alginolyticus strains were more adherent than V. parahaemolyticus. Only V. alginolyticus ATCC 17749 was found to be able to form biofilm on polystyrene microplate wells (OD570 = 0.532). Adherence to Vero cells showed that all tested strains were non adherent after 30 min, however after 60 min all the studied strains become adherent. The percentage of adherence ranged from1.23% to 4.66%. Neste estudo, investigou-se a produção de muco por cepas de Vibrio alginolyticus e Vibrio parahaemolyticus através do teste em placa de ágar com vermelho congo. Estudou-se também a capacidade de adesão à superfícies abióticas e células Vero. Os resultados indicaram que somente V. alginolyticus ATCC 17749produziu muco, formando colônias quase negras nas placas de ágar com vermelho congo. O teste de adesão a tubos de vidro indicou que as cepas de V. alginolyticus foram mais aderentes do que as de V. parahaemolyticus. Somente V. alginolyticus ATCC 17749 foi capaz de formar biofilme nos poços das microplacas de poliestireno (OD570=0,532). Testes de adesão a células Vero mostraram que nenhuma das cepas apresentou adesão em 30 min, mas todas aderiram após 60 min. A porcentagem de adesão variou de 1,23% a 4,66%. more...

In this study we investigated the phenotypic slime production of Vibrio alginolyticus and Vibrio parahaemolyticus strains, food-borne pathogens, using a Congo red agar plate assay. Furthermore, we studied their ability to adhere to abiotic surfaces and Vero cells line. Our results showed that only V. alginolyticus ATCC 17749 was a slime-producer developing almost black colonies on Congo red agar plate. Adherence to glace tube showed that all V. alginolyticus strains were more adherent than V. parahaemolyticus. Only V. alginolyticus ATCC 17749 was found to be able to form biofilm on polystyrene microplate wells (OD570 = 0.532). Adherence to Vero cells showed that all tested strains were non adherent after 30 min, however after 60 min all the studied strains become adherent. The percentage of adherence ranged from1.23% to 4.66%.Neste estudo, investigou-se a produção de muco por cepas de Vibrio alginolyticus e Vibrio parahaemolyticus através do teste em placa de ágar com vermelho congo. Estudou-se também a capacidade de adesão à superfícies abióticas e células Vero. Os resultados indicaram que somente V. alginolyticus ATCC 17749produziu muco, formando colônias quase negras nas placas de ágar com vermelho congo. O teste de adesão a tubos de vidro indicou que as cepas de V. alginolyticus foram mais aderentes do que as de V. parahaemolyticus. Somente V. alginolyticus ATCC 17749 foi capaz de formar biofilme nos poços das microplacas de poliestireno (OD570=0,532). Testes de adesão a células Vero mostraram que nenhuma das cepas apresentou adesão em 30 min, mas todas aderiram após 60 min. A porcentagem de adesão variou de 1,23% a 4,66%. 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 electron micrographs showed a reduction of the cells size and an evolution to coccoid-shapes. After 6 months of resuscitation,Salmonella enterica serovar Agona cells recuperated their original rod shape. The resuscitate cells ofSalmonella enterica serovar Agona were identified by multiplex PCR following the simultaneous amplification of thephoP, Hin andH-li genes. 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, fnb A, cna, Clf A) Polymerase Chain Reaction was used. Qualitative biofilm production of S. aureus using CRA plates revealed that 56.5% of strains were slime producers. In addition 78.26% of strains were ica A and ica D positive. While the fnbA gene was present in 76.1% of isolated strains. Furthermore, 56.5% of strains have the cna gene and 30.4% were clfA positives. Overall this study confirms the presence of fnb A and ica A/ica D genes in the majority of studies S. aureus strains isolated from Staphylococcal sepsis. more...

Salmonella bovismorbificans, rare serovar, isolated from patient in Tunisia were incubated during 13 years in soil. After its resuscitation, the cells showed a biochemical profile completely inactive on Api 20E system. These cells recuperated their initial characters after 6 months of incubation in Tryptic Soy broth. The atomic force micrographs showed a reduction of the cells size and an evolution to coccoid-shapes. After resuscitation S. bovismorbificans cells recuperated their original rod shape. These cells showed an altered envelope. The resuscitate cells were identified by PCR following the amplification of the internal transcribed spacer (ITS) region of 16S–23S rRNA gene. more...

This study was carried out to explore the adaptive mechanisms of Salmonella enterica serovar Typhimurium, in particular the implication of fatty acids (FA) in the remodeling of membrane lipid composition to overcome the combined effects of long-term starvation and γ-irradiation stresses. In addition, cell surface hydrophobicity was also evaluated. The bacterial strains (control and starved) were treated with a nonlethal γ-irradiation dose of 0.5 kGy and sublethal doses of 1 kGy. Gas chromatography analysis showed that the FA composition of starved and γ-irradiated cells was modified. However starvation combined with γ-irradiation induced more modifications in the FA composition than γ-irradiation or starvation alone. Indeed, the unsaturated FA-to-saturated FA ratio decreased significantly for both strains compared with γ-irradiated cells, as main consequence of the cyclic FA formation. Our results showed that starvation, irradiation, or combined stresses significantly influenced the hydrophobicity, and this may have affected the virulence state of Salmonella Typhimurium cells. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive to the ionizing radiation combined with long-term starvation stress. more...

International audience; Vibrio parahaemolyticus and V. alginolyticus, marine foodborne pathogens, were treated with UVC-radiation (240 J/m(2)) 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 identified by mass spectrometry (MS and MS/MS) and analysis revealed that OmpW, OmpA, Long-chain fatty acid transport protein, Outer membrane receptor protein, Putative uncharacterized protein VP0167, Maltoporin (lamB), Polar flagellin B/D, Agglutination protein Peptidoglycan-associated lipoprotein and MltA-interacting protein MipA were appeared, thereby they can be considered as UVC-stress proteins in some vibrios. In addition, expression of OmpK decreased to non-detectable level. Furthermore, we observed a decrease or an increase in the expression level of other outer membrane proteins. more...

The foodborne pathogen Salmonella enterica serovar Typhimurium was subjected to starvation in seawater microcosms for three years to study modifications in its outer membrane and extracellular protein profiles. After incubation, outer membrane proteins and extracellular proteins profiles of stressed bacteria were found to be altered when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). These modifications were shown by the appearance of bands, as well as the level of expression of certain proteins. The expression levels of sopE2, invA, sipA and sopBvirulence genes were also studied by reverse transcriptase polymerase chain reaction. Our findings showed that the expression level of sopE2 was slightly decreased under starvation. Whereas the quantities of sopB mRNA were increased in the two starved strains S1 and S2. The expression of sipA was decreased in strain S1 after starvation, but was significantly increased in strain S2. Key words: Salmonella, starvation, alteration, outer membrane protein, extracellular proteins, virulence gene expression. more...

In this work, we incubated four Shigella strains for one month at room temperature and at 4°C. Their adhesion capacity to KB cells, biofilm formation on microplate and surface hydrophobicity of starved cells were investigated. Our results showed that the stressed cells exhibited a remarkable increase in their hydrophobicity from 19 to 34 % and in their capacity to produce biofilm. Adherence assays to KB cells showed an increase in the number of adherent cells from 0.7 to 6.7% after one month of incubation in seawater. However, the percentage of invasion was decreased from 34 to 11% under stress condition. more...

International audience; In this study, Vibrio parahaemolyticus and Vibrio alginolyticus, marine foodborne pathogens, were treated with Ultraviolet-C (UV-C) irradiation (240 J.m(-2)) to evaluate alterations in their virulence genes expression levels. Firstly, we searched for the presence of eight Vibrio cholerae virulence genes, toxR, toxS, toxRS, ctxA, zot, ace, toxT, and virulence pathogenicity island (VPI), in the genome of investigated strains. The expression of toxR and toxS genes in UVC-irradiated bacteria, studied by reverse transcriptase polymerase chain reaction, was found to be altered. These variations were manifested by an increase or a decrease in the expression level of tested virulence genes. Further, the mRNA quantities of VPI and ace genes remained stable after treatment. more...

In this study, we incubated Vibrio parahaemolyticus and Vibrio alginolyticus (marine food-borne pathogens bacteria) in seawater for 8 months to study their morphologic, proteomic and genetic responses to starvation. The atomic force micrographs of stressed strains showed a reduction of the cells size and an evolution to two coccoid-shape forms whose length is less than 0.4 μm and between 0.5 and 1 μm. Extracellular protein patterns and gelatinase profiles of stressed bacteria were also altered. Indeed, these modifications were manifested by the appearance and/or disappearance of bands as well as in the level of expression of certain proteins. In addition, we also searched for the presence of eight Vibrio cholerae virulence genes: toxR, toxS, toxRS, ctxA, zot,ace, toxT, and Virulence Pathogenicity Island (VPI) in the genome of investigated strains. The expression level of VPI gene studied by reverse transcriptase polymerase chain reaction was decreased, whereas the mRNA quantities of toxR, toxS, and ace in starved Vibrio remained stable. Key words: Vibrio, seawater, alterations, morphology, proteins secreted, virulence gene expression, RT-PCR more...

Interest in extracellular lipase sourced from the non conventional yeast Yarrowia lipolytica has increased over the last decade. The enzyme was recently suggested as a good candidate for pancreatic exocrine insufficiency treatment. However, there is still a lack of oral safety evaluation data. In this work, we conducted acute and 28-day repeated dose toxicity studies in rats. Both male and female rats were first orally treated with fungal lipase at either single or repeated doses. The results demonstrated that neither single dose nor chronic administration of lipase was associated with mortality or abnormalities in general conditions, behavior and growth. Except a decrease in urine pH and a dose-unrelated increase of triglycerides observed in males, chronic administration of lipase resulted in similar hematological, blood biochemical and urine parameters to those of untreated animals. Minor histopathological changes were observed in lungs and livers of treated and untreated animals but they were considered of no toxicological significance. This study provides, for the first time, safety data on Yarrowia lipolytica extracellular lipase that support its use as a pharmaceutical. more...

International audience; 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 size 0.45 microm. Outer membrane proteins patterns of stressed bacteria were also altered. Indeed, these modifications were manifested by the appearance and/or disappearance of bands as well as in the level of expression of certain proteins. Plasmids profiles analysis showed that V. alginolyticus ATCC 33787 lost three plasmids, whereas other tested strains conserved their initial profiles. more...

International audience; In this study, we investigated the pathogenic potency of two Vibrio alginolyticus strains isolated from cultured gilthead Dicentrarchus labrax and Sparus 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 levels were then determined, virulence levels ranged from 1.03 x 10(5) to 1.0 x 10(6) CFU/fish. In addition, we also searched for the presence of eight Vibrio cholerae virulence genes: ctxA, zot, ace, toxR, toxS, toxRS, toxT, and Virulence Pathogenicity Island (VPI), in the genome of two isolated strains of V. alginolitycus. The in vivo expression of toxR, toxS, VPI and ace genes in both fish species, was tested by reverse transcriptase polymerase chain reaction. Indeed, we have noted that for each strain all the virulence genes selected were expressed in sea bream as well as in sea bass. more...