Discovering the Potentials of Four Phage Endolysins to Combat Gram-Negative Infections.

Endolysin-based therapeutics are promising antibacterial agents and can successfully supplement the existing antibacterial drugs array. It is specifically important in the case of Gram-negative pathogens, e.g.

Lipopolysaccharide of the Complex.

Lipopolysaccharide (LPS), localized in the outer leaflet of the outer membrane, serves as the major surface component of the Gram-negative bacterial cell envelope responsible for the activation of the host's innate immune system. Variations of the LPS structure utilized by Gram-negative bacteria promote survival by providing resistance to components of the innate immune system and preventing recognition by TLR4. This review summarizes studies of the biosynthesis of Yersinia pseudotuberculosis complex LPSs, and the roles of their structural components in molecular mechanisms of yersiniae pathogenesis and immunogenesis.

Peculiarities of the ultrastructure of mixed biofilms of the causing agent of diphtheria and conditionally pathogenic microorganisms isolated from the human respiratory tract.

Unlabelled: In the post-epidemic period, the circulation of the causative agent of diphtheria in the population is maintained due to the carrier of bacteria. Entering an organism with a high level of antitoxic immunity, the pathogen enters into intermicrobial interactions with representatives of the opportunistic microflora inhabiting the respiratory tract and forms a biofilm.

Materials And Methods: Modeling of the biofilm formation process was carried out using the strains C.

Characterization and genomic analysis of Exiguobacterium alkaliphilum B-3531D, an efficient crude oil degrading strain.

The aim of the work was to carry out the physiological, biochemical and genetic characterization of the B-3531D strain. This strain is promising for use in the field of environmental biotechnology, since it has a pronounced ability to utilize crude oil and individual hydrocarbons in a wide temperature range. The genome of the strain was sequenced and completely assembled, it consists of a 2,903,369 bp circular chromosome and two circular plasmids, namely, pE73 (73,590 bp) and pE52 (52,125 bp).

Novel Bacteriophage Aristophanes Encoding Structural Polysaccharide Deacetylase.

appears to be one of the most crucial nosocomial pathogens. A possible component of antimicrobial therapy for infections caused by extremely drug-resistant strains may be specific lytic bacteriophages or phage-derived enzymes. In the present study, we observe the biological features, genomic organization, and phage-host interaction strategy of novel virulent bacteriophage Aristophanes isolated on strain having K26 capsular polysaccharide structure.

Is It Possible to Create Antimicrobial Peptides Based on the Amyloidogenic Sequence of Ribosomal S1 Protein of ?

The development and testing of new antimicrobial peptides (AMPs) represent an important milestone toward the development of new antimicrobial drugs that can inhibit the growth of pathogens and multidrug-resistant microorganisms such as Gram-negative bacteria. Most AMPs achieve these goals through mechanisms that disrupt the normal permeability of the cell membrane, which ultimately leads to the death of the pathogenic cell. Here, we developed a unique combination of a membrane penetrating peptide and peptides prone to amyloidogenesis to create hybrid peptide: "cell penetrating peptide + linker + amyloidogenic peptide".

Structure of the K87 capsular polysaccharide and KL87 gene cluster of Acinetobacter baumannii LUH5547 reveals a heptasaccharide repeating unit.

K87 capsular polysaccharide (CPS) was isolated from Acinetobacter baumannii isolate LUH5547 that carries the KL87 capsule biosynthesis gene cluster at the chromosomal K locus. Studies by sugar analysis, selective chemical cleavages, and 1D and 2D H and C NMR spectroscopy showed that the CPS has a branched heptasaccharide repeat (K unit) containing one residue each of d-glucose (d-Glсp), d-glucuronic acid (d-GlсpA), N-acetyl-d-glucosamine (d-GlсpNAc), 6-deoxy-l-talose (l-6dTalp), and three residues of l-rhamnose (l-Rhap). The following structure of the CPS was established: →3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-6dTalp-(1→3)-β-D-GlcpNAc-(1→2↑1β-D-GlcpA-(4←1)-α-D-Glcp(2←1)-α-L-Rhap The position of a minor O-acetyl group present in the CPS was not determined.

Effect of 4-Hexylresorcinol on the Efficiency of Antibiotic Treatment of Experimental Sepsis Caused by Antibiotic-Resistant Klebsiella pneumoniae Strain in Mice.

High efficiency of a combined preparation including synergistic polymyxin B and 4-hexylresorcinol was shown for treatment of experimental sepsis caused by an antibiotic-resistant highly virulent hypermucoid Klebsiella pneumoniae strain KPM9Pm in mice. Complex therapy with polymyxin B (1 mg/kg) and 4-hexylresorcinol (30 mg/kg) led to cure in 80%; in 20% of these mice, no bacterial cells were found. After treatment with polymyxin B alone, only 50% animals survived and all of them contained bacterial cells.

The K26 capsular polysaccharide from Acinetobacter baumannii KZ-1098: Structure and cleavage by a specific phage depolymerase.

The KL26 gene cluster responsible for the synthesis of the K26 capsular polysaccharide (CPS) of Acinetobacter baumannii includes rmlBDAC genes for l-rhamnose (l-Rhap) synthesis, tle to generate 6-deoxy-l-talose (l-6dTalp) from l-Rhap, and a manC gene for D-mannose (D-Manp) that is rare in Acinetobacter CPS. K26 CPS material was isolated from A. baumannii isolate KZ-1098, and studied by sugar analysis, Smith degradation, and one and two-dimensional H and C NMR spectroscopy before and after O-deacetylation with aqueous ammonia.

Multidrug-Resistant Causing Severe Infections in the Neuro-ICU.

The purpose of this study was the identification of genetic lineages and antimicrobial resistance (AMR) and virulence genes in isolates associated with severe infections in the neuro-ICU. Susceptibility to antimicrobials was determined using the Vitek-2 instrument. AMR and virulence genes, sequence types (STs), and capsular types were identified by PCR.

Comparative tests of quality of bacteriological investigation with Corynebacterium diphtheriae isolation.

The results of comparative experimental studies of identification of nontoxigenic C. diphtheriae strain by three different commercial laboratories are presented. A typical nontoxigenic strain of C.

Comparative Study of In Situ Techniques to Enlarge Gold Nanoparticles for Highly Sensitive Lateral Flow Immunoassay of SARS-CoV-2.

Three techniques were compared for lowering the limit of detection (LOD) of the lateral flow immunoassay (LFIA) of the receptor-binding domain of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) based on the post-assay in situ enlargement of Au nanoparticles (Au NPs) on a test strip. Silver enhancement (growth of a silver layer over Au NPs-Au@Ag NPs) and gold enhancement (growth of a gold layer over Au NPs) techniques and the novel technique of galvanic replacement of Ag by Au in Au@Ag NPs causing the formation of Au@Ag-Au NPs were performed. All the enhancements were performed on-site after completion of the conventional LFIA and maintained equipment-free assay.

Identification of Amyloidogenic Regions in Ribosomal S1 Protein.

Bacterial S1 protein is a functionally important ribosomal protein. It is a part of the 30S ribosomal subunit and is also able to interact with mRNA and tmRNA. An important feature of the S1 protein family is a strong tendency towards aggregation.

The sensitivity of planktonic cultures and biofilms of gram-negative bacteria to commercial disinfectant and antiseptic preparations.

The in vitro antibacterial activity of 11 commercial disinfectant preparations and 8 antiseptics against 10 strains of the bacteria Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloaceae and Providencia stuartii obtained from international collections and isolated from neuroresuscitation patients in Moscow in 2018 was studied. The sensitivity of planktonic cultures to the preparations was determined by the method of serial dilutions in broth and the spot method on solid nutrient media, the sensitivity of biofilms by the applicator method. A general pattern was revealed: the level of sensitivity to tested disinfectants in clinical strains was lower than in reference strains.

Possibilities of practical application of different culture mediums for laboratory diagnostic of diphtheria.

The purpose of the work is to evaluate the cultural and morphological properties of colonies of clinically significant corynebacteria on culture mediums for the isolation of corynebacteria. The study used 9 culture mediums for the isolation of corynebacteria: a culture medium for the isolation of corynebacteria (Corynebacagar); Tellurite-containing blood agars on base - Culture medium № 1 GRM, Culture agar for the cultivation of microorganisms (GRM agar), Culture medium for determining the sensitivity of microorganisms to antibacterial preparations - AGV, culture agar for the cultivation of dry microorganisms (SPA), Clauberg medium II, Hoyle Medium agar (Oxoid), Blood agar base (Conda), Columbia Agar Base (Conda). The work used 7 test strains of microorganisms from the State collections of pathogenic microorganisms - C.

[Antibacterial effects of peptides synthesized based on the sequence of ribosome protein S1].

Antibiotic resistance of bacteria is a topical problem on a global scale. Sometimes vigorous human activity leads to an increase in the number of bacteria carrying resistance genes in the environment. Antimicrobial peptides (AMPs) and similar compounds are potential candidates for combating antibiotic-resistant bacteria.

Efficiency of bacteriological transport media quality control.

The aim of the study is to assess the effectiveness of quality control of transport environments in accordance with the requirements of domestic and international standards using aerobic and optional anaerobic microorganisms. The results of a comparative assessment of the survival of 10 strains of aerobic and optional anaerobic microorganisms after storage in the semi-liquid transport environment of Ames for 24 and 48 hours at temperatures (4-8)0 C and (20-25)0 C in accordance with the requirements of domestic and international standards are presented. The methodology described in ICC 4.

K106 and K112: Two Structurally and Genetically Related 6-Deoxy-l-talose-Containing Capsular Polysaccharides.

Whole genome sequences of two clinical isolates, 48-1789 and MAR24, revealed that they carry the KL106 and KL112 capsular polysaccharide (CPS) biosynthesis gene clusters, respectively, at the chromosomal K locus. The KL106 and KL112 gene clusters are related to the previously described KL11 and KL83 gene clusters, sharing genes for the synthesis of l-rhamnose (l-Rha) and 6-deoxy-l-talose (l-6dTal). CPS material isolated from 48-1789 and MAR24 was studied by sugar analysis and Smith degradation along with one- and two-dimensional 1H and 13C NMR spectroscopy.

Novel Myovirus TaPaz Encoding Two Tailspike Depolymerases: Characterization and Host-Recognition Strategy.

, one of the most significant nosocomial pathogens, is capable of producing structurally diverse capsular polysaccharides (CPSs) which are the primary receptors for bacteriophages encoding polysaccharide-degrading enzymes. To date, bacterial viruses specifically infecting strains belonging to more than ten various capsular types (K types) were isolated and characterized. In the present study, we investigate the biological properties, genomic organization, and virus-bacterial host interaction strategy of novel myovirus TaPaz isolated on the bacterial lawn of strain with a K47 capsular polysaccharide structure.

Ag-Doped and Antibiotic-Loaded Hexagonal Boron Nitride Nanoparticles as Promising Carriers to Fight Different Pathogens.

Utilization of antibacterial components-conjugated nanoparticles (NPs) is emerging as an attractive strategy for combating various pathogens. Herein, we demonstrate that Ag/BN NPs and antibiotic-loaded BN and Ag/BN nanoconjugates are promising carriers to fight bacterial and fungal infections. Extensive biological tests included two types of Gram-positive methicillin-resistant strains (B8469 and MW2), two types of Gram-negative strains (ATCC27853 and B1307/17), and 47 types of strains (including 41 multidrug-resistant ones), as well as five types of fungal cultures: (candidiasis-thrush) ATCC90028 and ATCC24433, ATCC90018, CBS109113, and We have demonstrated that, even within a single genus , there are many hospital strains with multi-drug resistance to different antibiotics.

Carriage of Capsular Serotype K1 Klebsiella pneumoniae Sequence Type 23 Strains in Healthy Microbiology Laboratory Staff in Russia.

causes both nosocomial and community-associated infections. Among the hypervirulent (hvKP) isolates, K1 is the most common capsular serotype. Here, we report the draft genome sequences of 3 K1-type (sequence type 23) strains isolated from healthy microbiology laboratory staff in Russia.