Antibiotic (Bulgaria)

Abstract BackgroundKlebsiella pneumoniae(KP), often multidrug-resistant (MDR), is a significant public health concern and frequently associated with various diseases including urinary-tract infection. In addition, in recent years, an increasing number of studies reports on the emergence of convergent KP that combine MDR with hypervirulence leading to severely limited treatment options and thus calling for alternative approaches.MethodsIn this study, we compared high-risk clonal KP lineages with less pathogenicKlebsiella variicola(KV) andKlebsiella quasipneumoniae(KQ) strains on multiple-omics levels and performed integrative data analysis to identify unique markers that could be subsequently leveraged as novel targets in alternative treatment strategies.ResultsOur initial genomic analysis revealed 107 genes as part of the patho-core genome in eight clinical KP that were associated with different metabolic pathways. Subsequent transcriptome and proteome analyses in infection-mimicking media demonstrated similar regulatory patterns among KP vs. otherKlebsiellastrains, again with metabolic responses playing a pivotal role. In total, we identified 193 KP-specific, differentially expressed genes on transcriptomic and/or proteomic levels. When then comparing these regulated genes to over 6,000 publicly availableKlebsiellagenomes, we identified unique markers either in KP genomes or adaptively regulated on transcriptomics and/or proteomics levels. An example for the latter was a gene cluster for the cellobiose phosphotransferase system that has been previously described in the context of bacterial virulence and biofilm formation.ConclusionIn conclusion, our study not only highlights that KP strains demonstrate metabolic flexibility in response to particular environmental conditions, which is potentially important for their success as opportunistic pathogens, but identified unique KP-markers. Subsequent studies are needed to explore whether these markers might be prospectively used as novel anti-virulence targets, providing alternatives to traditional antibiotics.

The use of perioperative, prophylactic, intravenous antibiotics is standard practice to reduce the risk of surgical site infection after oncologic resection and complex endoprosthetic reconstruction for lower extremity bone tumors. However, evidence guiding the duration of prophylactic treatment remains limited. To assess the effect of a 5-day regimen of postoperative, prophylactic, intravenous antibiotics compared with a 1-day regimen on the rate of surgical site infections within 1 year after surgery. This randomized clinical superiority trial was performed at 48 clinical sites in 12 countries from January 1, 2013, to October 29, 2019. The trial included patients with a primary bone tumor or a soft tissue sarcoma that had invaded the femur or tibia or oligometastatic bone disease of the femur or tibia with expected survival of at least 1 year who required surgical management by excision and endoprosthetic reconstruction. A total of 611 patients were enrolled, and 7 were excluded for ineligibility. A 1- or 5-day regimen of postoperative prophylactic intravenous cephalosporin (cefazolin or cefuroxime) that began within 8 hours after skin closure and was administered every 8 hours thereafter. Those randomized to the 1-day regimen received identical saline doses every 8 hours for the remaining 4 days; patients, care providers, and outcomes assessors were blinded to treatment regimen. The primary outcome in this superiority trial was a surgical site infection (superficial incisional, deep incisional, or organ space) classified according to the criteria established by the Centers for Disease Control and Prevention within 1 year after surgery. Secondary outcomes included antibiotic-related complications, unplanned additional operations, oncologic and functional outcomes, and mortality. Of the 604 patients included in the final analysis (mean [SD] age, 41.2 [21.9] years; 361 [59.8%] male; 114 [18.9%] Asian, 43 [7.1%] Black, 34 [5.6%] Hispanic, 15 [2.5%] Indigenous, 384 [63.8%] White, and 12 [2.0%] other), 293 were randomized to a 5-day regimen and 311 to a 1-day regimen. A surgical site infection occurred in 44 patients (15.0%) allocated to the 5-day regimen and in 52 patients (16.7%) allocated to the 1-day regimen (hazard ratio, 0.93; 95% CI, 0.62-1.40; P = .73). Antibiotic-related complications occurred in 15 patients (5.1%) in the 5-day regimen and in 5 patients (1.6%) allocated to the 1-day regimen (hazard ratio, 3.24; 95% CI, 1.17-8.98; P = .02). Other secondary outcomes did not differ significantly between treatment groups. This randomized clinical trial did not confirm the superiority of a 5-day regimen of postoperative intravenous antibiotics over a 1-day regimen in preventing surgical site infections after surgery for lower extremity bone tumors that required an endoprosthesis. The 5-day regimen group had significantly more antibiotic-related complications. ClinicalTrials.gov Identifier: NCT01479283.

WFSR report 2021.014 | 9 Summary National Reference Laboratories (NRLs) are part of the system responsible for the control and enforcement of EU food and feed law. Wageningen Food Safety Research (WFSR) has been designated as the NRL for thirteen subjects. The tasks of a NRL depend on its research fields. This report gives an overview of the activities performed by all of NRLs of WFSR in 2020. These NRLs are for: milk and milk products, marine biotoxins, animal proteins, certain substances and residues thereof as laid down in Directive 96/23/EC, additives for use in animal nutrition (feed additives), genetically modified organisms (GMOs) in food and feed, pesticides, metals and nitrogenous substances in feed and food, mycotoxins and plant toxins in food and feed, processing contaminants, halogenated persistent organic pollutants in food and feed, food borne viruses and water content of poultry. This report first gives an overview of relevant legislation and information on the networks of EURLs, NRLs and OLs. For every NRL, a description is then given of all activities performed in the EURL-NRL network such as participation in EURL-NRL workshops, working groups, and proficiency and comparative tests. This is followed by a description of the assistance given to OLs in the form of quality control and/or advice. Finally, the scientific and technical support given to the competent authority is discussed. In some cases, the contact with other NRLs is discussed. An important NRL task is to stay up to date with current developments within its NRL domain. Every EURL organises one or two meetings (workshops) every year for that purpose. Participation in these EURL-NRL workshops is mandatory. In 2020, due to COVID-19, most of these workshops were online. All workshops have been attended by NRLs of WFSR. Additionally, the NRLs have actively participated in EURL working groups, to improve analytical methods. To test the analytical capabilities of NRLs, the EURLs organise proficiency tests. Due to EURL proficiency tests sometimes being limited in their scope, the NRLs have also participated in proficiency tests organised by other organizations if thought to be relevant. Most results (z-scores) in these proficiency tests were good; only a few ‘questionable’ and a few ‘unsatisfactorily’ result were reported. Follow-up actions were implemented in those cases. The performance of the OLs has been assured by checking the results of their performance in proficiency tests (organised by other laboratories or the NRL) or by sending assurance-samples. Some OLs have also received technical support with regard to their analyses.

This review summarizes recent advances in C–S and C–Se formationsviatransition metal-catalyzed C–H functionalization utilizing directing groups to control the site-selectivity.

A novel method to synthesize C2-phosphorylmethylindoles via the carbocation formation initiated tandem phosphorylative allenylation/cyclization of 1-(o-aminophenyl)prop-2-ynols with the P(O)–H species has been developed.

Abstract Background Rational antibiotic prescribing is crucial to combat antibiotic resistance. Optimal strategies to improve antibiotic use are not known. Strama, the Swedish strategic program against antibiotic resistance, has been successful in reducing antibiotic prescription rates. This study investigates whether two specific interventions directed toward healthcare centers, an informational visit and a self-evaluation meeting, played a role in observed reduction in rates of antibiotic prescriptions in primary healthcare.Methods The study was a retrospective, observational, empirical analysis exploiting the variation in the timing of the interventions and considering past prescriptions through use of estimations from dynamic panel data models. Primary healthcare data from 2011 to 2014 were examined. Data were from public and private primary healthcare centers in western Sweden. The key variables were prescription of antibiotics and indicator variables for the two interventions.Results The first intervention, an educational information intervention, decreased the number of prescriptions among public healthcare centers, but this effect was only temporary. We found no proof that the second intervention, a self-evaluation meeting at the healthcare center, had an impact on the reduction of prescriptions.Conclusions Single educational interventions aimed at influencing rates of antibiotic prescriptions have limited impact. A multifaceted approach is needed in efforts to reduce the use of antibiotics in primary health care.

The addition of an antibacterial agent to dental implants may provide the opportunity to decrease the percentage of implant failures due to peri-implantitis. For this purpose, in this study, the potential efficacy of nanosilver-doped titanium biomaterials was determined. Titanium disks were incorporated with silver nanoparticles over different time periods by Tollens reaction, which is considered to be an eco-friendly, cheap, and easy-to-perform method. The surface roughness, wettability, and silver release profile of each disc were measured. In addition, the antibacterial activity was also evaluated by using disk diffusion tests for bacteria frequently isolated from the peri-implant biofilm: Streptococcus mutans, Streptococcus mitis, Streptococcus oralis, Streptococcus sanguis, Porphyromonas gingivalis, Staphylococcus aureus, and Escherichia coli. Cytotoxicity was evaluated in vitro in a natural human osteoblasts cell culture. The addition of nanosilver significantly increased the surface roughness and decreased the wettability in a dose-dependent manner. These surfaces were significantly toxic to all the tested bacteria following a 48-hour exposure, regardless of silver doping duration. A concentration of 0.05 ppm was sufficient to inhibit Gram-positive and Gram-negative species, with the latter being significantly more susceptible to silver ions. However, after the exposure of human osteoblasts to 0.1 ppm of silver ions, a significant decrease in cell viability was observed by using ToxiLight™ BioAssay Kit after 72 hours. Data from the present study indicated that the incorporation of nanosilver may influence the surface properties that are important in the implant healing process. The presence of nanosilver on the titanium provides an antibacterial activity related to the bacteria involved in peri-implantitis. Finally, the potential toxicological considerations of nanosilver should further be investigated, as both the antibacterial and cytotoxic properties may be observed at similar concentration ranges.

Palladium-catalyzed highly selective intramolecular addition of C–N and S–N bonds to alkynes has been achieved, and two distinct kinds of functional indoles were synthesized rapidly from the same set of substrates in a catalyst-controlled manner.