The Escherichia coli fructose repressor, FruR, is known to regulate expression of several genes concerned with carbon utilization. Using a previously derived consensus sequence for FruR binding, additional potential operators were identified and tested for FruR binding in DNA band migration retardation assays. Operators in the control regions of operons concerned with carbon metabolism bound FruR, while those in operons not concerned with carbon metabolism did not. In vivo assays with transcriptional lacZ fusions showed that FruR controls the expression of FruR operator-containing genes encoding key enzymes of virtually every major pathway of carbon metabolism. Moreover, a fruR null mutation altered the rates of utilization of at least 36 carbon sources. In general, oxidation rates for glycolytic substances were enhanced while those for gluconeogenic substances were depressed. Alignment of FruR operators revealed that the consensus sequence for FruR binding is the same for operons that are activated and repressed by FruR and permitted formulation of a revised FruR-binding consensus sequence. The reported observations indicate that FruR modulates the direction of carbon flow by transcriptional activation of genes encoding enzymes concerned with oxidative and gluconeogenic carbon flow and by repression of those concerned with fermentative carbon flow.

Antimicrobial resistance is closely linked to antimicrobial use and is a growing concern worldwide. Antimicrobial resistance increases healthcare costs substantially in many countries, including Lebanon. National data from Lebanon have, in the most part, been limited to a few academic hospitals. The Lebanese Society of Infectious Diseases conducted a retrospective study to better describe the antimicrobial susceptibility patterns of bacterial isolates in Lebanon. Data were based on records retrieved from the bacteriology laboratories of 16 different Lebanese hospitals between January 2011 and December 2013. The susceptibility results of a total 20684 Gram-positive and 55594 Gram-negative bacteria were analyzed. The prevalence rate of methicillin-resistant Staphylococcus aureus was 27.6% and of vancomycin-resistant Enterococcus spp was 1%. Streptococcus pneumoniae had susceptibilities of 46% to oxacillin, 63% to erythromycin, and 98% to levofloxacin. Streptococcus pyogenes had susceptibilities of 94% to erythromycin and 95% to clindamycin. The mean ampicillin susceptibility of Haemophilus influenzae, Salmonella spp, and Shigella spp isolates was 79%, 81.3%, and 62.2%, respectively. The extended-spectrum beta-lactamase production rate for Escherichia coli was 32.3% and for Klebsiella spp was 29.2%. Acinetobacter spp showed high resistance to most antimicrobials, with low resistance to colistin (17.1%). Pseudomonas spp susceptibilities to piperacillin-tazobactam and imipenem were lower than 80% (79.7% and 72.8%, respectively). This study provides population-specific data that are valuable in guiding antimicrobial use in Lebanon and neighbouring countries and will help in the establishment of a surveillance system for antimicrobial resistance following the implementation of a nationwide standardization of laboratory methods and data entry.

Background. The oral cavity is potentially high-risk transmitter of COVID-19. Antimicrobial mouthrinses are used in many clinical preprocedural situations for decreasing the risk of cross-contamination in the dental setting. It is important to investigate the efficacy of mouthwash solutions against salivary SARS-CoV-2 in order to reduce the exposure of the dental team during dental procedures. Aims. The aim of this in vivo study was to evaluate the efficacy of 2 preprocedural mouthrinses in the reduction of salivary SARS-CoV-2 viral load and to compare the results of the mouthwashes to a control group. Materials and Methods. In this randomized-controlled clinical trial, studied group comprised laboratory-confirmed COVID-19 positive patients through nasopharyngeal swabs. Participants were divided into 3 groups. For 30 seconds, the control group mouthrinsed with distilled water, the Chlorhexidine group mouthrinsed with 0.2% Chlorhexidine and the Povidone-iodine group gargled with 1% Povidone-iodine. Saliva samples were collected before and 5 minutes after mouthwash. SARS-CoV-2 rRT-PCR was then performed for each sample. Evaluation of the efficacy was based on difference in cycle threshold (Ct) value. The analysis of data was carried out using GraphPad Prism version 5 for Windows. Kristal wullis and Paired t test were used. A probability value of less than 0.05 was regarded as statistically significant. Results. Sixty-one compliant participants (36 female and 25 male) with a mean age 45.3 ± 16.7 years-old were enrolled. A significant difference was noted between the delta Ct of distilled water wash and each of the 2 solutions Chlorhexidine 0.2% ( p = 0.0024) and 1 % Povidone-iodine ( p = 0.012). No significant difference was found between the delta Ct of patients using Chlorhexidine 0.2% and 1% Povidone-iodine solutions ( p = 0.24). A significant mean Ct value difference ( p < 0.0001) between the paired samples in Chlorhexidine group (n = 27) and also in Povidone-iodine group (n = 25) ( p < 0.0001) was found. In contrast, no significant difference ( p = 0.566) existed before and after the experiment in the control group (n = 9). Conclusion. Chlorhexidine 0.2% and 1% Povidone-iodine oral solutions are effective preprocedural mouthwashes against salivary SARS-CoV-2 in dental treatments. Their use as a preventive strategy to reduce the spread of COVID-19 during dental practice should be considered.

2019. Effect of carbapenem resistance on outcomes of bloodstream infection caused by Enterobacteriaceae in lowincome and middle-income countries (PANORAMA): a multinational prospective cohort study. Lancet Infectious Diseases 19 (6) , pp.

Background There is a lack of official national antimicrobial resistance (AMR) data in Lebanon. Individual hospitals generate their own antibiotic susceptibility data in the form of yearly pamphlets. Methods In this study, antibiotic susceptibility data from 13 hospitals distributed across different governorates of Lebanon were collected to conduct a compilation-based surveillance of AMR in Lebanon for the years 2015–2016. The findings were compared with those of a previous nationwide study in this country conducted between 2011 and 2013 as well as with similar data obtained from the 2015 and 2016 European surveillance reports of AMR. To provide a clear presentation of the AMR situation, mean percent susceptibility of different antibiotic–microbe combinations was calculated. Results During 2015–2016, the percent susceptibility of Enterobacteriaceae to third-generation cephalosporins and to carbapenems was 59 and 97%, respectively. Among Pseudomonas aeruginosa and Acinetobacter spp., carbapenem susceptibility reached 70 and 12%, respectively. Among Gram positive organisms, the percent susceptibility to methicillin in Staphylococcus aureus was 72%, that to vancomycin in Enterococcus spp. was 98% and that to penicillin in Streptococcus pneumoniae was 75%. Compared with results of 2011–2013, there was an overall trend of decreased susceptibility of bacteria to the tested antibiotics, with a variation of 5 to 10%. The antibiotic susceptibility data from Lebanon were found to be comparable with those from Eastern and South-eastern European countries. Conclusion This study highlights the need to establish a robust national AMR surveillance system that enables data from Lebanon to be included in global AMR maps. Electronic supplementary material The online version of this article (10.1186/s13756-019-0487-5) contains supplementary material, which is available to authorized users.