Vancomycin Reduces Cell Wall Stiffness and Slows Swim Speed of the Lyme Disease Bacterium

Decoding the Structural Diversity: A New Horizon in Antimicrobial Prospecting and Mechanistic Investigation

The escalating crisis of antimicrobial resistance (AMR) underscores the urgent need for novel antimicrobials. One promising strategy is the exploration of structural diversity, as diverse structures can lead to diverse biological activities and mechanisms of action. This review delves into the role of structural diversity in antimicrobial discovery, highlighting its influence on factors such as target selectivity, binding affinity, pharmacokinetic properties, and the ability to overcome resistance mechanisms. We discuss various approaches for exploring structural diversity, including combinatorial chemistry, diversity-oriented synthesis, and natural product screening, and provide an overview of the common mechanisms of action of antimicrobials. We also describe techniques for investigating these mechanisms, such as genomics, proteomics, and structural biology. Despite significant progress, several challenges remain, including the synthesis of diverse compound libraries, the identification of active compounds, the elucidation of complex mechanisms of action, the emergence of AMR, and the translation of laboratory discoveries to clinical applications. However, emerging trends and technologies, such as artificial intelligence, high-throughput screening, next-generation sequencing, and open-source drug discovery, offer new avenues to overcome these challenges. Looking ahead, we envisage an exciting future for structural diversity-oriented antimicrobial discovery, with opportunities for expanding the chemical space, harnessing the power of nature, deepening our understanding of mechanisms of action, and moving toward personalized medicine and collaborative drug discovery. As we face the continued challenge of AMR, the exploration of structural diversity will be crucial in our search for new and effective antimicrobials.

Approach to prediction and receiver operating characteristic analysis of a regression model for assessing the severity of the course Lyme borreliosis in children

Introduction

Lyme borreliosis (LB) is a multisystemic zoonotic disease transmitted by the bite of infected tick vectors.The aim of the study is to develop a mathematical model for predicting the risk of severity of Lyme disease by the risk factor of the disseminated form of LB in children who have had a tick attack. To test the effectiveness of the formula for predicting the development of the disseminated stage of LB, we built a receiver operating characteristic (ROC) curve and determined the specificity and sensitivity of our model. The results of the examination of 122 patients with the confirmed local and disseminated stages of LB were taken as a basis.

Material and methods

To build a prognostic model for prediction of the risk of the developing of the stage in LB predicting the risk of severity of course in Lyme borreliosis (PRSCLB), 122 children (aged 13 ±3 years) with LB were examined using multivariate regression analysis, including 52 boys and 70 girls. Groups of patients: 79 children with erythema migrans, 16 with Lyme arthritis, and 27 with nervous system involvement by LB. The quality of the prognostic model was checked by the Nagelkerke R Square (Nagelkerke R2) and the acceptability of this model was assessed using ROC analysis.

Results

The method of multivariate regression analysis for predicting severe course and organ and system damage in LB in children, taking into account the factors and variants of the disease itself, makes it possible to develop a mathematical model for predicting the relative response factors (RRF) of severe forms of Lyme disease and will improve the effectiveness of treatment. This will create all the prerequisites for high-quality preventive measures and reduce the relative response factors rate.The initial data for predicting the severity of LB were 28 factors. According to the results of regression analysis, 24 factors were included in the model for predicting the severity of LB.

Conclusions

The results of the study showed that the multifactorial model predicts the severity and organ and system damage in LB in children with an accuracy of 95%. The ROC curve, which was built on the basis of the results, has an area under the curve of 0.94, which indicates the high efficiency of the model.

Borrelia peptidoglycan interacting Protein (BpiP) contributes to the fitness of Borrelia burgdorferi against host-derived factors and influences virulence in mouse models of Lyme disease

The Peptidoglycan (PG) cell wall of the Lyme disease (LD) spirochete, Borrelia burgdorferi (Bb), contributes to structural and morphological integrity of Bb; is a persistent antigen in LD patients; and has a unique pentapeptide with L-Ornithine as the third amino acid that cross-links its glycan polymers. A borrelial homolog (BB_0167) interacted specifically with borrelilal PG via its peptidoglycan interacting motif (MHELSEKRARAIGNYL); was localized to the protoplasmic cylinder of Bb; and was designated as Borrelia peptidoglycan interacting Protein (BpiP). A bpiP mutant displayed no defect under in vitro growth conditions with similar levels of several virulence-related proteins. However, the burden of bpiP mutant in C3H/HeN mice at day 14, 28 and 62 post-infection was significantly lower compared to control strains. No viable bpiP mutant was re-isolated from any tissues at day 62 post-infection although bpiP mutant was able to colonize immunodeficient SCID at day 28 post-infection. Acquisition or transmission of bpiP mutant by Ixodes scapularis larvae or nymphs respectively, from and to mice, was significantly lower compared to control strains. Further analysis of bpiP mutant revealed increased sensitivity to vancomycin, osmotic stress, lysosomal extracts, human antimicrobial peptide cathelicidin-LL37, complement-dependent killing in the presence of day 14 post-infection mouse serum and increased internalization of CFSC-labeled bpiP mutant by macrophages and dendritic cells compared to control strains. These studies demonstrate the importance of accessory protein/s involved in sustaining integrity of PG and cell envelope during different phases of Bb infection.

The unusual cell wall of the Lyme disease spirochaete Borrelia burgdorferi is shaped by a tick sugar

Peptidoglycan-a mesh sac of glycans that are linked by peptides-is the main component of bacterial cell walls. Peptidoglycan provides structural strength, protects cells from osmotic pressure and contributes to shape. All bacterial glycans are repeating disaccharides of N-acetylglucosamine (GlcNAc) β-(1-4)-linked to N-acetylmuramic acid (MurNAc). Borrelia burgdorferi, the tick-borne Lyme disease pathogen, produces glycan chains in which MurNAc is occasionally replaced with an unknown sugar. Nuclear magnetic resonance, liquid chromatography-mass spectroscopy and genetic analyses show that B. burgdorferi produces glycans that contain GlcNAc-GlcNAc. This unusual disaccharide is chitobiose, a component of its chitinous tick vector. Mutant bacteria that are auxotrophic for chitobiose have altered morphology, reduced motility and cell envelope defects that probably result from producing peptidoglycan that is stiffer than that in wild-type bacteria. We propose that the peptidoglycan of B. burgdorferi probably evolved by adaptation to obligate parasitization of a tick vector, resulting in a biophysical cell-wall alteration to withstand the atypical torque associated with twisting motility.

Adverse reactions of vancomycin in humans: A protocol for meta-analysis

BACKGROUND

Vancomycin is effective against Gram-positive bacteria and considered as a last resort in the case of ineffective use of other antigens. While due to the occurrence of adverse reactions, the application of vancomycin is strictly limited. We will conduct a meta-analysis to summarize adverse reactions of vancomycin in humans.

METHODS

To collect comprehensive randomized controlled trials (RCTs), the following electronic databases will be searched: PubMed, Embase, Web of Science, Cochrane Library, the China National Knowledge Infrastructure, Chinese Biomedical Literature Database, and China Science and Technology Journal Database. The range of publication time will be from the inception of the database to August 2020 without language limitation. Two reviewers will independently conduct selection of studies, data extraction and management, and assessment of risk of bias. Any disagreement will be resolved by discussion with the third reviewer. Review Manager 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration) will be used for meta-analysis. The Cochrane risk of bias tool will be used to assess the risk of bias.

RESULTS

This study will synthesize the data from the present eligible high quality RCTs to explore the incidence of adverse reactions such as hypersensitivity reactions, nephrotoxicity, ototoxicity, phlebitis, and agranulocytosis.

CONCLUSION

This meta-analysis will provide systematic evidence for adverse reactions of vancomycin in humans.

STUDY REGISTRATION NUMBER

INPLASY202080094.

Evaluation of the clinical relevance of vancomycin for the treatment of Lyme disease

Vancomycin is active in vitro and in vivo in mouse systems against Lyme disease borrelia; however, there are no published data on the efficacy of vancomycin in patients with Lyme disease and no convincing theoretical advantages of vancomycin over the currently used and highly effective orally administered antimicrobial agents, including doxycycline, amoxicillin and cefuroxime axetil. In addition, vancomycin may cause a wide variety of potentially serious adverse effects and requires the placement of an intravenous catheter. It is concluded that vancomycin is a much less attractive option for the treatment of patients with early Lyme disease (or any other manifestation of Lyme disease), compared with the antimicrobials currently being used. Based on available evidence, clinical studies to evaluate the safety and efficacy of vancomycin for Lyme disease cannot be recommended.

Identifying Vancomycin as an Effective Antibiotic for Killing Borrelia burgdorferi

Borrelia burgdorferi is the causative agent of Lyme borreliosis. Antibiotic therapy of early acute infection is effective for most patients, but 10 to 20% go on to develop posttreatment Lyme disease syndrome (PTLDS). The nature of PTLDS remains unknown, but currently approved antibiotics for the treatment of Lyme disease do not appear to impact these symptoms after they have developed. We reason that minimizing the time the pathogen interacts with the host will diminish the probability of developing PTLDS, irrespective of its nature. This calls for an efficient eradication of the pathogen during acute infection. In search of a superior killing antibiotic, we examined approved antibiotics for their ability to kill B. burgdorferi Vancomycin proved more effective in killing the pathogen in vitro than ceftriaxone, the standard of care for disseminated B. burgdorferi infection. Both compounds were also the most effective in killing stationary-phase cells. This is surprising, given that inhibitors of cell wall biosynthesis are known to only kill growing bacteria. We found that peptidoglycan synthesis continues in stationary-phase cells of B. burgdorferi, explaining this paradox. A combination of vancomycin and gemifloxacin sterilized a stationary-phase culture of B. burgdorferi Examination of the action of antibiotics in severe combined immunodeficient (SCID) mice showed that doxycycline, a standard of care for uncomplicated acute infection, did not clear the pathogen. In contrast, both ceftriaxone and vancomycin cleared the infection. A trial examining the early use of more potent antibiotics on the development of PTLDS may be warranted.

Surface enhanced fluorescence and nanoscopic cell wall deformation in adhering Staphylococcus aureus upon exposure to cell wall active and non-active antibiotics

In infections, bacteria often adhere to surfaces and become deformed by the forces with which they adhere. Nanoscopic cell wall deformation defines bacterial responses to environmental conditions and is likely influenced by antibiotics. Here, staphylococcal cell wall deformation upon exposure to cell wall active and non-active antibiotics or their combinations is compared for two green-fluorescent (GFP) isogenic Staphylococcus aureus strains adhering to a gold surface, of which one lacks peptidoglycan cross-linking. Exposure to cell wall active antibiotics caused greater cell wall deformation than a buffer control in the GFP parent and in the Δpbp4GFP isogenic mutant, as measured by surface-enhanced-fluorescence. Cell wall non-active antibiotics only yielded greater deformation than a buffer control in the parent strain, while combinations of cell wall active and non-active antibiotics did not cause greater cell wall deformation. 3D-analysis of the impact of adhesion forces and Young's moduli of the cell wall, both measured using atomic force microscopy, led to the conclusion that increased deformation was mainly due to cell wall weakening and not due to the effects of antibiotics on adhesion forces. Interactions between bacteria and antibiotics are mostly studied using planktonic bacteria, while during infection, bacteria are in an adhering state that deforms their cell wall and therewith influences their adaptive responses. We anticipate that the demonstration of cell wall weakening in adhering bacteria under the influence of antibiotics and the role of peptidoglycan herein will aid in the development of new antibiotics. Surface-enhanced-fluorescence may accordingly develop into a new, highly-sensitive method for diagnosing antibiotic-resistant bacteria.