Antimicrobial activity of quantum dots: an experimental study

Тhe purpose of the study is to analyze their antimicrobial activity in a bacteriological laboratory.Цель работы – анализ противомикробной активности в условиях бактериологической лаборатории

Laboratory Analysis of the Anti-Infectious Activity of Quantum Dots and Bioconjugates Based on Them in the Aspect of the Prospects for the Treatment of Inflammatory Diseases of the Eye. Experimental Research (Part 3)

This article presents the third part of an experimental study on the prospects and possibilities of using quantum dots and bioconjugates created on their basis in the treatment of inflammatory diseases of the eye. Taking into account the previously obtained results on the possibility of “safe” use of CdTe/Cd and InP/ZnSe/ZnS quantum dots on an animal model under conditions of intravitreal administration, the aim of the current stage was to analyze their antimicrobial activity in a bacteriological laboratory. Materials and methods. As QDs, we took two types of artificial fluorophores capable of generating superoxide radicals synthesized according to a special technical assignment at the Federal State Unitary Enterprise “Research Institute of Applied Acoustics”, Dubna, Moscow Region: type 1 - colloidal solution of QD CdTe/Cd MPA 710 10 % of the mass. Type 2 - colloidal solution of QD InP/ZnSe/ZnS 650 10 % wt. The study included “museum” and nosocomial strains of microorganisms, and the activity of points was assessed using the disk-diffusion method, followed by an assessment of the zones of inhibition of bacterial growth. Concentrations of 0.1 %, 0.01 %, and 0.001 % quantum dots were tested, as well as solutions of bioconjugates (antibiotic + quantum dots) of Vancomycin, Levofloxacin, Ceftazidime and Cefotaxime. Results. Based on the data obtained, it was concluded that quantum dots potentiate the action of the sensitivity of individual microorganisms, both outpatient and hospital strains. © 2022 Ophthalmology Publishing Group. All rights reserved

Evaluation of Anti-Infectious Activity of Bioconjugates Based on Quantum Dots CdTe / Cd MPA 710 and Levofloxacin against Staphylococcal Corneal Infection. Experimental Research

Infectious keratitis is one of the leading causes of persistent decline in visual function and monocular blindness in both developed and developing countries. The combination of factors in the prevalence of eye infectious and inflammatory diseases, antibiotic resistance, and internal mutations of the pathogens themselves exacerbate the need to search for highly effective alternatives in the fight against eye infectious diseases. Of particular interest are the prospects for the use of fluorescent semiconductor nanocrystals, called quantum dots, in the treatment of resistant infectious inflammatory diseases. The objective of the study was to assess the anti- infectious activity of bioconjugates based on CdTe / Cd MPA 710 quantum dots and levofloxacin against staphylococcal corneal infection using the example induced infectious keratitis in laboratory animals. As the object of the study, 6 male (6 eyes) New Zealand rabbits were studied, which underwent induction of bacterial keratitis by introducing a hospital strain of S. Aureus into the structure of the cornea. The following were used as antimicrobial agents: a solution of levofloxacin 5 ml for epibulbar use and a bioconjugate based on CT CdTe / Cd MPA 710 and levofloxacin. © 2022 Ophthalmology Publishing Group. All rights reserved

Evaluation of the Anti-Infectious Activity of the Complex Based on Quantum Dots InP / ZnSe / ZnS 650 and Tobramycin Against Pseudomonas Aeruginosa Infection of the Cornea. Experimental Research

Microbial keratitis (MK) is a homogeneous group of diseases accompanied by loss of the corneal epithelium, stromal leukocyte infiltration and/or destructive tissue breakdown, occurring when the protective mechanisms of the ocular surface are disturbed, which require an immediate set of therapeutic measures, including, first of all, massive etiotropic therapy, which is represented, as a rule, by broad-spectrum antibiotics (AB) and anti-inflammatory drugs. One of the most threatening MK pathogens is P. aeruginosa (PA) (Pseudomonas aeruginosa). Multiple drug resistance, the highest pathogenicity, numerous RA virulence factors dictate the need to search for new highly effective methods to combat MC, in the etiological structure of which RA dominates. The most promising direction in this area is the use of artificial fluorophores, in particular quantum dots (QDs). The objective of this study was to evaluate the anti-infectious activity of the complex based on InP/ZnSe/ZnS 650 quantum dots and Tobramycin against Pseudomonas aeruginosa infection of the cornea. As an object of study, laboratory New Zealand rabbits (No. 6) were studied — 2 females, 4 males, which were induced bacterial keratitis by introducing a nosocomial Ps strain. aeruginosa in the structure of the cornea. The following antimicrobial agents were used: Tobramycin solution 5 ml for epibulbar application and a bioconjugate based on QD InP/ZnSe/ZnS 650 and tobramycin. Laboratory animals were divided into 2 groups. Rabbits of the 1st group, after the manifestation of the clinical picture of microbial keratitis, received instillations of tobramycin drops into the conjunctival sac every 2 hours for 3 days with a complete absence of positive clinical dynamics and a subsequent transition from day 4 in order to anatomically preserve the eyeball to instillations of the CT InP/ZnSe/ZnS complex 650 + Tobramycin. Rabbits of the 2nd group received instillations of the CT + Tobramycin complex and showed positive dynamics in relation to the regression of symptoms from the 2nd day of therapy. As methods of dynamic observation, photoregistration of the anterior segment with fluorescein staining and optical coherence tomography of the anterior segment were used. A clinical experiment has demonstrated the highest efficiency of the InP/ZnSe/ZnS 650 + Tobramycin complex in relation to Pseudomonas aeruginosa strain resistant to Tobramycin monotherapy. © 2023 Ophthalmology Publishing Group. All rights reserved

Current etiological structure of bacteremia at the intensive care units of Yekaterinburg

In this report we present the results of bacteriological analysis of blood samples taken from patients at the intensive care units of Yekaterinburg city hospitals in 2006 - 2010. Studies were done in “BACTEC” (Beckton Dickinson) and “Walk/Away'1 (Siemens Healthcare) bacteriological automated systems. Highly resistant to antibiotics nosocomial strains of S. aureus (50.44%), Enterococcus spp. (19.77%), coagulase negative Staphilococcus spp. (9.25%), K. pneumoniae (7.98%), A baumannii (7.22%), E.coli (4.69%), P. Aerugionosa (3.8%) were isolated from adult patients with sepsis. Vancomycin and Unezolid remain highly active against Staphilococcus spp. and Enterococcus spp. (100% of strains were sensitive). Carbapenems are still actual for the therapy of septic conditions caused by representatives of Enterobacteriaceae family (more than 99% of strains were sensitive). Isolates of P. aeruginosa and A. baumannii arise certain difficulties for the adequate choice of drugs because their sensitivity to antibiotics needs to be determined.В работе представлены результаты микробиологического исследования крови 4133 пациентов ОРИТ стационаров г. Екатеринбурга за 2006-201 Ог.г. Работа выполнена с использованием микробиологических анализаторов Bactec (Becton Dickinson, США) и Walk Away (Siemens,USA). Среди возбудителей сепсиса у взрослых пациентов преобладают штаммы высокорезистентной госпитальной флоры S. aureus (50,44%), Enterococcus spp. (19,77%), коагулазоотрицательные стафилококки (9,25%), К. pneumoniae (7,98%), A. baumannii (7,22%), E.coli (4,69%), P. aeruginosa (3,8%). Ванкомицин и линезолид сохраняют высокую антибактериальную активность в отношении стафилококков и энтерококков (100% чувствительных штаммов). Карбапенемы продолжают оставаться препаратами выбора при терапии сепсиса, вызванного энтеробактериями (более 99% чувствительных штаммов). Наибольшую сложность для клинициста представляют случаи выделения P. aeruginosa, A. baumannii, при которых для подбора адекватной терапии требуется определение антибиотикочувствительности

Investigating hypoxia in aquatic environments: diverse approaches to addressing a complex phenomenon

In this paper we provide an overview of new knowledge on oxygen depletion (hypoxia) and related phenomena in aquatic systems resulting from the EU-FP7 project HYPOX (“In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and landlocked water bodies”, www.hypox.net). In view of the anticipated oxygen loss in aquatic systems due to eutrophication and climate change, HYPOX was set up to improve capacities to monitor hypoxia as well as to understand its causes and consequences. Temporal dynamics and spatial patterns of hypoxia were analyzed in field studies in various aquatic environments, including the Baltic Sea, the Black Sea, Scottish and Scandinavian fjords, Ionian Sea lagoons and embayments, and Swiss lakes. Examples of episodic and rapid (hours) occurrences of hypoxia, as well as seasonal changes in bottom-water oxygenation in stratified systems, are discussed. Geologically driven hypoxia caused by gas seepage is demonstrated. Using novel technologies, temporal and spatial patterns of watercolumn oxygenation, from basin-scale seasonal patterns to meter-scale sub-micromolar oxygen distributions, were resolved. Existing multidecadal monitoring data were used to demonstrate the imprint of climate change and eutrophication on long-term oxygen distributions. Organic and inorganic proxies were used to extend investigations on past oxygen conditions to centennial and even longer timescales that cannot be resolved by monitoring. The effects of hypoxia on faunal communities and biogeochemical processes were also addressed in the project. An investigation of benthic fauna is presented as an example of hypoxia-devastated benthic communities that slowly recover upon a reduction in eutrophication in a system where naturally occurring hypoxia overlaps with anthropogenic hypoxia. Biogeochemical investigations reveal that oxygen intrusions have a strong effect on the microbially mediated redox cycling of elements. Observations and modeling studies of the sediments demonstrate the effect of seasonally changing oxygen conditions on benthic mineralization pathways and fluxes. Data quality and access are crucial in hypoxia research. Technical issues are therefore also addressed, including the availability of suitable sensor technology to resolve the gradual changes in bottom-water oxygen in marine systems that can be expected as a result of climate change. Using cabled observatories as examples, we show how the benefit of continuous oxygen monitoring can be maximized by adopting proper quality control. Finally, we discuss strategies for state-of-the-art data archiving and dissemination in compliance with global standards, and how ocean observations can contribute to global earth observation attempts