Nailya A. Zigangirova

The aim of the study was to evaluate the efficacy of fluorothiazinone in a real-world clinical setting. Material and methods. The paper presents the initial results of clinical application of combination therapy for infectious and inflammatory complications following endourological surgeries using the new antibacterial drug fluorothiazinone in a urology department. Clinical and laboratory data were analyzed, and the results of microbiological examination methods were examined. Results. Analysis of body temperature dynamics revealed a significant decrease in temperature in the fluorothiazinone group, with the average body temperature on day 3 being closer to normal than in the control group. Clinical improvement was observed in 92.3 % of patients on day 3 of therapy, compared to 37 % in the control group. In the fluorothiazinone group, stable positive dynamics in reducing inflammatory markers were observed on day 3 of therapy. Fluorothiazinone has been demonstrated to be effective in suppressing biofilm formation, and significant cytotoxicity suppression of clinical isolates of K. pneumoniae has been demonstrated in vitro. Conclusion: Given the multidrug resistance of hospital-acquired strains, timely initiation of antibacterial therapy based on local microbiological monitoring in combination with the new drug fluorothiazinone has proven effective in treating this complex group of patients.

Introduction. Vibrio cholerae motility plays a key role in the pathogenesis of cholera, so finding ways to suppress it is a promising approach to combating this infection. Objective: to study the effect of Fluorothiazinone on the motility of V. cholerae. Materials and methods. Flagellar motility was determined in 0.3% agar, with the motility zone measured, in 40 strains V. cholerae El Tor of varying epidemiological significance. The ability of these strains to acquire resistance to Fluorothiazinone was also assessed through repeated subcultures on alkaline agar containing Fluorothiazinone (100 mg/L). Results. A significant decrease in the motility of all studied cultures was observed in the presence of Fluorothiazinone, without the development of resistance. Conclusion. The dose-dependent ability of Fluorothiazinone to reduce the motility of V. cholerae was demonstrated for the first time.

Представлены основные этапы разработки фтортиазинона — инновационного антибактериального препарата с уникальным механизмом действия, заключающемся в торможении механизма вирулентности, специфического для Грам(–)-возбудителей. Фтортиазинон не действует на классические мишени бактерий (ферменты синтеза компонентов клеточной стенки, белков, нуклеиновых кислот и проч.) и поэтому не оказывает бактериостатического или бактерицидного действия. Мишенью действия фтортиазинона является система секреции III типа и жгутик, необходимые для распространения возбудителя и ингибирования клеток врожденного иммунитета. Механизм действия фтортиазинона объясняет отсутствие отрицательного действия на нормальную микрофлору и значительный профиль безопасности. Приведены данные о фармакокинетике препарата, показания к применению и перспективы его дальнейшего расширения.

The aim of this study was to investigate the effect of the innovative Russian antibacterial drug Fluorothiazinone, an inhibitor of the type III secretion system and flagellar function, on the virulence properties of urinary tract infection (UTI) pathogens. Materials and methods. Clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa species were obtained from 4 patients with recurrent UTI. Cytotoxicity analysis was performed on HeLa cells using the CytoTox 96 kit. Bacterial flagellar motility was assessed in 0.25% agar by measuring the zone of motility. Biofilms were cultivated in 96-well plates and stained with crystal violet and Congo red. Biofilm structure was assessed by microscopy, and the bacterial biofilm and exopolysaccharide matrix were quantified by measuring the optical density of the dye bound to the biofilm. Intracellular development was studied in PC-3 cells by determining the number of intracellular bacteria using a cell lysate plating method and an immunochemical method involving staining the bacteria with specific antibodies. Results. The Fluorothiazinone antibacterial specifically inhibited the cytotoxicity and motility of E. coli and P. aeruginosa. For K. pneumoniae, susceptibility to Fluorothiazinone was observed, associated with the suppression of cytotoxicity. For all the isolates studied, inhibition of biofilm formation on an abiotic surface was demonstrated. For E. coli and K. pneumoniae, a significant decrease in intracellular replication within human prostate adenocarcinoma cells and suppression of intracellular bacterial community formation were observed. Conclusion. Fluorothiazinone disrupts mechanisms that contribute to pathogen persistence in the formation of chronic UTI, including biofilm formation on abiotic surfaces such as catheters, stents, and drains, and the formation of intracellular bacterial communities and dormant intracellular reservoirs.

Extraintestinal pathogenic Escherichia coli causes community-acquired and nosocomial pneumonia, and poses a risk of infection, especially for patients with impaired lung function, such as patients with cystic fibrosis (CF). When chronic infection develops, eradication of the pathogen is difficult even with aggressive antibacterial therapy and targeted CF treatment. A new compound, Fluorthiazinone (CL-55), an inhibitor of bacterial virulence, was registered in Russia in 2024. The aim of our study was to characterize the genomes of E. coli ST648 isolated from long-term infected CF patients, describe AMR and virulence factors, and investigate the effect of CL-55 on CF isolates in vitro. Comparison of the genomes of hypermucoviscous isolates showed that, in the presence of a large number of core genes, the isolates have adaptive differences both in chromosome and in the composition and genes of the plasmidome. Both isolates formed mature biofilms on an abiotic surface and were able to survive and proliferate inside macrophages. CL-55 in in vitro experiments was effective in suppressing E. coli ST648 in both the aggregate and intracellular states, which allows us to propose the use of Fluorothiazinone as a combinative therapy to facilitate eradication of pathogenic microorganisms in the respiratory tract of patients with CF.

Introduction. Infections of the lower respiratory tract by bacteria of the Pseudomonadota phylum: Pseudomonas aeruginosa, Burkholderia spp., Achromobacter spp. are critical to the quality and life expectancy of patients with cystic fibrosis (CF). When the infection is chronic, eradication of bacteria with existing antibacterial drugs is practically impossible. To explore alternative drugs, trials are needed on bacteria isolated from CF patients and characterized using genomic approaches. The objective of our study was a comparative analysis of virulence factors of 6 isolates of bacteria of the Pseudomonadota phylum and testing the efficacy of the innovative drug Fluorothiazinone (FT) in suppressing the pathogenicity of bacteria in vitro. Materials and methods. Isolates of A. ruhlandii ST36, A. xylosoxidans ST555, B. cepacia ST2140, B. gladioli ST2141, P. aeruginosa ST859 and ST198 were examined using whole-genome sequencing and bioinformatics analysis to search for resistance and virulence determinants. The FT drug was tested for its effect on bacteria in in vitro experiments on cytotoxicity on HeLa cells, motility and biofilm formation. Results. Genomic studies have confirmed the arsenal of resistance determinants, especially the efflux systems of bacteria isolated from patients with CF, and the diversity of virulence factors, among which we identified factors in the categories of motility, signals of quorum-sensing systems, secretion systems, exotoxins, as the most essential for the adaptation of bacteria to conditions of the lower respiratory tract. In vitro tests of the FT drug showed its effectiveness in suppressing cytotoxicity (2.6–4.0 times), motility (2.0–3.6 times) and the process of biofilm formation (2.0–7.7 times). Conclusion. For the first time, the effectiveness of the innovative antibacterial drug Fluorothiazinone has been shown against bacteria of the Pseudomonadota phylum, isolated from chronically infected patients with CF, with the described potential of virulence factors.

В результате исследования была разработана и валидирована ВЭЖХ-МС/МС-методика количественного определения нового антибактериального лекарственного вещества фтортиазинон в плазме крови человека с использованием внутреннего стандарта. В ходе валидационной оценки была подтверждена селективность, правильность и прецизионность метода, отсутствие значительного эффекта переноса и эффекта матрицы, а также влияния разбавления образцов. Градуировочная кривая линейна в диапазоне концентраций 0,1 – 300 нг/мл, коэффициент детерминации r² > 0,9990. Нижний предел количественного определения составил 0,1 нг/мл. Установлено, что исследуемый аналит стабилен при хранении в виде рабочего раствора (в течение 6 ч при комнатной температуре), в образцах плазмы (в течение 6 ч при комнатной температуре, после трех циклов заморозки-разморозки, в течение 30 дней при –70 °C) и после пробоподготовки в автосамплере (при +10 °C в течение 24 ч).