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Aim: The purpose of this study is to evaluate the anti-biofilm capacity of Diode laser 980 nm, triple antibiotic mixture and calcium hydroxide.Methods: Eighty five single-rooted teeth with mature apices were prepared using Protaper Universal rotary nickel titanium system till size # F4 then contaminated with E.faecalis. Irrigation done using 2.5% sodium hypochlorite followed by 17% EDTA. Samples were divided into 4 groups (n= 20) according to the irrigant activation method. Laser group,TAP group, Ca(OH)2group and the control group. Residual bacteria were plated onto Brain Heart Infusion media and determined as colony-forming units (CFU mL-1). Data were analyzed using one way ANOVA followed by performance of Tukey post hoc tests. Significance was set at p < 0.05.Results: There was a statistically significant reduction in the mean numbers of colony-forming units among all groups. However, none of the activation methods was able to kill E. faecalis biofilm completely. The Laser group behaved most effectively among all groups.Conclusion: The adjunctive use of 980nm laser is an effective method for bacterial reduction after chemo-mechanical instrumentation of the root canal.

International audience; G-quadruplexes (G4) are non-canonical DNA and/or RNA secondary structures formed in guanine-rich regions. Given their over-representation in specific regions in the genome such as promoters and telomeres, they are likely to play important roles in key processes such as transcription, replication or RNA maturation. Putative G4-forming sequences (G4FS) have been reported in humans, yeast, bacteria, viruses and many organisms. Here we present the first mapping of G-quadruplex sequences in Dictyostelium discoideum, the social amoeba. ‘Dicty’ is an ameboid protozoan with a small (34 Mb) and extremely AT rich genome (78%). As a consequence, very few G4-prone motifs are expected. An in silico analysis of the Dictyostelium genome with the G4Hunter software detected 249–1055 G4-prone motifs, depending on G4Hunter chosen threshold. Interestingly, despite an even lower GC content (as compared to the whole Dicty genome), the density of G4 motifs in Dictyostelium promoters and introns is significantly higher than in the rest of the genome. Fourteen selected sequences located in important genes were characterized by a combination of biophysical and biochemical techniques. Our data show that these sequences form highly stable G4 structures under physiological conditions. Five Dictyostelium genes containing G4-prone motifs in their promoters were studied for the effect of a new G4-binding porphyrin derivative on their expression. Our results demonstrated that the new ligand significantly decreased their expression. Overall, our results constitute the first step to adopt Dictyostelium discoideum as a ‘G4-poor’ model for studies on G-quadruplexes.

Water-pipe (WP) smoking is the most common method of tobacco consumption in the Middle-East and is rapidly spreading on a global scale. Although, water-pipe smoking is linked to various diseases, such as emphysema and various types of cancers, its effect on testosterone levels has yet to be investigated. This study explores the effect of water-pipe smoking on serum testosterone levels in males in Qatar. In this cross-sectional sample within a cohort study, we retrieved data for a total of 1000 male volunteers from the Qatar BioBank (QBB) project. A self-reported questionnaire was used to determine the water-pipe smoking status of participants. Moreover, participants were stratified based on the frequency of smoking. Total testosterone and sex hormone binding globulin (SHBG) were measured clinically, whereas free testosterone and bioavailable testosterone were calculated using Vermeulen's equation. Hormone values of 541 males (277 water-pipe smokers and 264 non-smokers) were compared using multiple regression analysis based on water-pipe smoking status after adjusting for confounding factors. No statistically significant difference was observed between WP smokers and non-water-pipe smokers in the likelihood of having lower or higher total testosterone, after adjustment for confounding factors. Similar results were found in free testosterone, bioavailable testosterone, and sex hormone binding globulin (all p>0.05). When compared with the reference group, both light and heavy water-pipe smokers had a similar likelihood of circulating low total testosterone levels (OR=0.83, 95% CI: 0.46-1.49; and OR=0.80, 95% CI: 0.43-1.49; respectively). Our results reveal, for the first time, that there is no significant change in total testosterone, free testosterone, bioavailable testosterone and sex hormone binding globulin in waterpipe smokers compared to non-water-pipe smokers. Therefore, we believe that further studies are needed to confirm the effect of water-pipe smoking on testosterone in different populations. This work was supported by the College of Medicine of Qatar University and grant QUST-2-CMED-2018-1 from Qatar University.

The immunity profile against H5N1 highly pathogenic avian influenza (HPAI) in the commercial poultry value chain network in Egypt was modeled with the use of different vaccination scenarios. The model estimated the vaccination coverage, the protective seroconversion level, and the duration of immunity for each node of the network and vaccination scenario. Partial budget analysis was used to compare the benefit-cost of the different vaccination scenarios. The model predicted that targeting day-old chick avian influenza (AI) vaccination in industrial and large hatcheries would increase immunity levels in the overall poultry population in Egypt and especially in small commercial poultry farms (from 60%). This strategy was shown to be more efficient than the current strategy of using inactivated vaccines. Improving HPAI control in the commercial poultry sector in Egypt would have a positive impact to improve disease control.

Background and objectives: Pseudomonas aeruginosa possesses a variety of virulence factors that may contribute to its pathogenicity. P. aeruginosa also has a large number of virulence factors such as exotoxin A, exoenzyme S, nan 1 and Las genes. The aim of this study was to evaluate oprI, oprL as reliable factors for rapid identification of P. aeruginosa and to detect toxA, exo S, nan1 and LasB genes by Polymerase Chain Reaction (PCR). Materials and methods: In this study 30 isolates of P. aeruginosa were recovered from burn, pulmonary tract and blood infections. Results and conclusions: The oprI and oprL genes were detected in all of 30 P. aeruginosa isolates collected. The presence of toxA gene in isolates from burn and pulmonary tract was significantly higher than that from blood. All tested isolates harbored LasB gene. However, difference between exoS prevalence in isolates from pulmonary tract and burn isolates was statistically significant higher than that from blood. The prevalence of nan1 gene was significantly higher in isolates of pulmonary tract and burn specimens than isolates from blood. Molecular methods have been reported to be superior to the phenotypic methods for identification of P. aeruginosa by designing a multiplex PCR assay based on oprI and oprL genes for molecular detection of P. aeruginosa Determination of different virulence genes of P. aeruginosa isolates suggests that they are associated with different levels of intrinsic virulence and pathogenicity. Significant correlations between some virulence genes and source of infections indicates implementation of infection control measures will help in controlling the dissemination of virulence genes among P. aeruginosa isolates.

The effectiveness of recombinant turkey herpesvirus avian influenza (A/swan/Hungary/4999/2006(H5N1)) clade 2.2 virus (rHVT-H5) vaccine was evaluated in two layer chicken breeds (White Bovans [WB] and Brown Shaver [BS]). One dose of rHVT-H5 vaccine was administered at day 1 and birds were monitored serologically (haemagglutination inhibition test) and virologically for 19 weeks. Maternally-derived antibody and post-vaccination H5 antibody titres were measured using the Chinese (A/Goose/Guangdong/1/96(H5N1)) HA and the Egyptian (A/chicken/Egypt/128s/2012(H5N1)) HA as antigens. The challenge was conducted at 19 weeks of age and on six experimental groups: Groups I (WB) and II (BS), both vaccinated and challenged; Groups III (WB) and IV (BS), both vaccinated but not challenged; Groups V and VI, unvaccinated specific pathogen free chickens, serving respectively as positive and negative controls. The challenge virus was the clade 2.2.1 highly pathogenic avian influenza H5N1 A/chicken/Egypt/128s/2012 at a dose of 10(6) median embryo infective dose. For both breeds, complete maternally-derived antibody waning occurred at the age of 4 weeks. The immune response to rHVT-H5 vaccination was detected from the sixth week. The seroconversion rates for both breeds reached 85.7 to 100% in the eighth week of age. Protection levels of 73.3%, 60% and 0% were respectively recorded in Groups I, II and V. No mortalities occurred in the unchallenged groups. Group I showed superior results for all measured post-challenge parameters. In conclusion, a single rHVT-H5 hatchery vaccination conferred a high level of protection for a relatively extended period. This vaccine could be an important tool for future A/H5N1 prevention/control in endemic countries. Further studies on persistence of immunity beyond 19 weeks, need for booster with inactivated vaccines, breed susceptibility and vaccinal response, and transmissibility are recommended.

BACKGROUND Several methods have been proposed for rapid detection of drug resistance of Mycobacterium tuberculosis (M. tuberculosis). High resolution melting (HRM) curve analysis has been developed for accurate and simultaneous detection of resistance of M. tuberculosis isolates to rifampicin (RIF) and isoniazid (INH). Other techniques include the resazurin microtiter assay (REMA) which is one of the new colorimetric phenotypic methods. The present study evaluated the HRM curve analysis and REMA assay in comparison to the proportional method (PM) for rapid identification of multidrug resistant (MDR) M. tuberculosis isolates. METHODS Thirty M. tuberculosis clinical isolates of known resistance phenotypes were used. An HRM curve was generated for each isolate to scan for mutations in the rpoB and katG genes to detect RIF and INH resistance, respectively. The REMA colorimetric assay was also evaluated using the same isolates. The results of both techniques were compared to the gold standard proportional method. RESULTS The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the REMA assay for RIF and INH susceptibility testing were 100%. The HRM curve assay results for RIF susceptibility testing were 92.3%, 100%, 100%, 94.4%, and 96.7%, respectively, and for INH they were 85%, 100%, 100%, 76.9%, and 90%, respectively. CONCLUSIONS REMA is a rapid non-conventional and inexpensive method and may serve as a replacement for the proportion method in resource limited settings, while the PPV and NPV of the HRM curve make this assay an ideal screening method for the TB laboratory.