Cell Surface Of Bacteria Research Articles

PlzR regulates type IV pili assembly in Pseudomonas aeruginosa via PilZ binding

Type IV pili (T4P) are thin, flexible filaments exposed on the cell surface of gram-negative bacteria and are involved in pathogenesis-related processes, including cell adsorption, biofilm formation, and twitching motility. Bacteriophages often use these filaments as receptors to infect host cells. Here, we describe the identification of a protein that inhibits T4P assembly in Pseudomonas aeruginosa, discovered during a screen for host factors influencing phage infection. We show that expression of PA2560 (renamed PlzR) in P. aeruginosa inhibits adsorption of T4P-dependent phages. PlzR does this by directly binding the T4P chaperone PilZ, which in turn regulates the ATPase PilB and results in disturbed T4P assembly. As the plzR promoter is induced by cyclic di-GMP, PlzR might play a role in coupling T4P function to levels of this second messenger.

The human gut Bacteroides eggerthii expresses a new galactofuranose-containing lipooligosaccharide with weak immunostimulatory properties

Lipopolysaccharides (LPS) decorating the cell surface of Gram-negative bacteria exhibit nuanced functionalities linked to their precise structural composition. However, despite their critical role in health and disease, information on the structure and function of LPS from members of the human gut microbiota is still limited. Here, we deciphered the complete structure of the LPS isolated from the human gut bacterium Bacteroides eggerthii 1_2_48FAA. We showed that B. eggerthii 1_2_48FAA produces an R-type LPS (or lipooligosaccharide, LOS) composed of a heterogeneous mixture of tetra- and penta-acylated lipid A species with different degree of phosphorylation, and a compact galactofuranose-containing core oligosaccharide. Using in vitro human cell lines, we showed that B. eggerthii 1_2_48FAA LOS acts as a weak activator of TLR4-mediated signaling. Moreover, we observed that expression of maturation markers CD40, CD80 and CD86 on monocytes-derived dendritic cells upon B. eggerthii 1_2_48FAA LOS exposure was significantly lower compared to pro-inflammatory Escherichia coli LPS. Taken together, these data provide new structural and biological insights into LPS from gut bacteria, underscoring the importance of structural features in modulating host immunity.

KpsS1 Mediates the Glycosylation of Pseudaminic Acid in Acinetobacter Baumannii.

Pseudaminic acid (Pse) is found in the polysaccharide structures of the cell surface of various Gram-negative pathogenic bacteria including Acinetobacter baumannii and considered as an important component of cell surface glycans including oligosaccharides and glycoproteins. However, the glycosyltransferase that is responsible for the Pse glycosylation in A. baumannii remains unknown yet. In this study, through comparative genomics analysis of Pse-positive and negative A. baumannii clinical isolates, we identified a potential glycosyltransferase, KpsS1, located right downstream of the Pse biosynthesis genetic locus. Deletion of this gene in an Pse-positive A. baumannii strain, Ab8, impaired the glycosylation of Pse to the surface CPS and proteins, while the gene knockout strain, Ab8ΔkpsS1, could still produce Pse with 2.86 folds higher amount than that of Ab8. Furthermore, impairment of Pse glycosylation affected the morphology and virulence potential of A. baumannii, suggesting the important role of this protein. This study will provide insights into the further understanding of Pse in bacterial physiology and pathogenesis.

Role of Rickettsial Outer Membrane Protein A in the Pathogenesis of Rickettsial Diseases

Diseases caused by Rickettsiales are often overlooked, although they pose important public health concerns. The Rickettsiales family comprises a broad range of intracellular bacteria with distinct evolutionary adaptations, making the development of treatment measures to combat infections, such as vaccines or antibiotics, a challenge. Interestingly, the outer membrane protein A (OmpA) was found to exist in the cell surface of most human pathogenic bacteria in the order Rickettsiales. However, knowledge about OmpA in each species and strain is scattered and ambiguous. In this study, we systematically compiled the existing information on OmpA and its relationship with human pathogenic rickettsiae to serve as a reference for future research. A comprehensive literature search was conducted using specific keywords across five databases. According to the literature, OmpA of spotted fever group rickettsia plays a crucial role as an adhesin and invasin that directly interacts with the surface of mammalian host cells to mediate bacterial localization in host cells. The presence of a premature stop codon in the amino acid sequence resulted in the secretion of non-functional OmpA, which is one of the main reasons for rickettsial strains or species to become avirulent. Similarly, OmpA also functions as an important adhesin in the Anaplasma family when it interacts with the sLex and sLex-like glycan of myeloid and endothelial cells, respectively. However, the OmpA of Anaplasma must be co-functional with the other two adhesins to promote bacterial internalization. Interestingly, certain sites in the amino acid residues of Ehrlichia and Orientia OmpA are predicted to be homologous to the binding domain region of Anaplasma OmpA. It is therefore suggested that OmpA is an important adhesin for bacteria to bind to their specific mammalian host cells.

Inhibitory Effects on Staphylococcus aureus Sortase A by Aesculus sp. Extracts and Their Toxicity Evaluation.

A promising strategy for combating bacterial infections involves the development of agents that disarm the virulence factors of pathogenic bacteria, thereby reducing their pathogenicity without inducing direct lethality. Sortase A, a crucial enzyme responsible for anchoring virulence factors to the cell surface of several pathogenic bacteria, has emerged as a possible target for antivirulence strategies. A series of hippocastanum species (Aesculus pavia, A. parviflora, Aesculus x carnea, and A. hippocastanum) were used to prepare ethanol- and water-based extracts for assessing their effect on Staphylococcus aureus sortase A. The extracts were characterized through HPLC analysis, and their polyphenols content was determined using the Folin-Ciocalteu method. The specific toxicity profile was evaluated in Daphnia magna using the median lethal concentration (LC50) and against the fibroblast MRHF cell line. The half maximal inhibitory concentration (IC50) values on sortase A, determined after 30 min of incubation, ranged from 82.70 to 304.31 µg/mL, with the A. pavia water extract exhibiting the highest inhibitory effect. The assessment of the A. pavia water extract on human fibroblasts revealed no significant signs of toxicity, even at a concentration of 500 µg/mL. This reduced toxicity was further validated through the Daphnia assay. These findings highlight the low toxicity and the potential of this extract as a promising source of future development of bacteria antivirulence solutions.

Influence of Bacteria in Self – Healing Fly Ash Concrete

Traditional concrete is considered brittle, rigid and susceptible to cracks. Synthetic polymers used for the repair of cracks are susceptible to ultraviolet radiations, high cost and emanate toxic gases. This project presents the results of an experimental investigation carried out to evaluate the influence of Bacillus Megaterium bacteria on the compressive strength, split tensile strength, flexural strength and self-healing characteristics of concrete made without and with fly ash. Cement was replaced with four percentages (10, 20, 30 and 40) with fly ash by weight. A cell concentration of 105 cells/ml of bacteria was used in making the concrete mixes. Tests were performed at the age of 28 days. Test results indicated that the inclusion of Bacillus Megaterium in fly ash concrete enhanced the compressive, split tensile and flexural strength. This improvement in strength was due to deposition on the bacteria cell surfaces within the pores. The present work highlights the influence of bacteria on the properties of concrete made with supplementary cementing material such as like fly ash. Usage of bacteria like Bacillus Megaterium improves strength and durability of fly ash concrete through self-healing effect

Europium Ion-Based Magnetic-Trapping and Fluorescence-Sensing Method for Detection of Pathogenic Bacteria.

Europium ions (Eu3+) have been utilized as a fluorescence-sensing probe for a variety of analytes, including tetracycline (TC). When Eu3+ is chelated with TC, its fluorescence can be greatly enhanced. Moreover, Eu3+ possesses 6 unpaired electrons in its f orbital, which makes it paramagnetic. Being a hard acid, Eu3+ can chelate with hard bases, such as oxygen-containing functional groups (e.g., phosphates and carboxylates), present on the cell surface of pathogenic bacteria. Due to these properties, in this study, Eu3+ was explored as a magnetic-trapping and sensing probe against pathogenic bacteria present in complex samples. Eu3+ was used as a magnetic probe to trap bacteria such as Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Acinetobacter baumannii, Bacillus cereus, and Pseudomonas aeruginosa. The addition of TC facilitated the easy detection of magnetic Eu3+-bacterium conjugates through fluorescence spectroscopy, with a detection limit of approximately ∼104 CFU mL-1. Additionally, matrix-assisted laser desorption/ionization mass spectrometry was employed to differentiate bacteria tapped by our magnetic probes.

Recent Advances in the Development of Polymyxin Antibiotics: 2010-2023.

The polymyxins are nonribosomal lipopeptides produced by Paenibacillus polymyxa and are potent antibiotics with activity specifically directed against Gram-negative bacteria. While the clinical use of polymyxins has historically been limited due to their toxicity, their use is on the rise given the lack of alternative treatment options for infections due to multidrug resistant Gram-negative pathogens. The Gram-negative specificity of the polymyxins is due to their ability to target lipid A, the membrane embedded LPS anchor that decorates the cell surface of Gram-negative bacteria. Notably, the mechanisms responsible for polymyxin toxicity, and in particular their nephrotoxicity, are only partially understood with most insights coming from studies carried out in the past decade. In parallel, many synthetic and semisynthetic polymyxin analogues have been developed in recent years in an attempt to mitigate the nephrotoxicity of the natural products. Despite these efforts, to date, no polymyxin analogues have gained clinical approval. This may soon change, however, as at the moment there are three novel polymyxin analogues in clinical trials. In this context, this review provides an update of the most recent insights with regard to the structure-activity relationships and nephrotoxicity of new polymyxin variants reported since 2010. We also discuss advances in the synthetic methods used to generate new polymyxin analogues, both via total synthesis and semisynthesis.

An idea to explore: Engaging high school students in structure-function studies of bacterial sortase enzymes and inhibitors - A comprehensive computational experimental pipeline.

High school science fairs provide an exceptional opportunity for students to gain experience with scientific research, and participation has positive outcomes with respect to chosen careers in the sciences. However, it can be challenging to engage high school students in university-level research outside of formal internship programs. Here, we describe an experimental pipeline for a computational structural biology project that engages high school students. Students are involved at every step of the investigation and utilize freely available software to dock inhibitors onto protein homologues, and then analyze the resulting complexes. Bacterial sortases are transpeptidases on the cell surface of Gram-positive bacteria and are a potential target for the development of antibiotics. Students modeled inhibitors bound to sortases from several organisms, asking questions about affinity and selectivity. Their project was ranked in the top 10% at both regional and state science fairs. This project design is easily adaptable to countless other protein systems and provides a pipeline for collaborative high school student/university professor inquiry.

Adaptation of the binding domain of Lactobacillus acidophilus S-layer protein as a molecular tag for affinity chromatography development.

The S-layer proteins are a class of self-assembling proteins that form bi-dimensional lattices named S-Layer on the cell surface of bacteria and archaea. The protein SlpA, which is the major constituent of the Lactobacillus acidophilus S-layer, contains in its C-terminus region (SlpA284 - 444), a protein domain (named here as SLAPTAG) responsible for the association of SlpA to the bacterial surface. SLAPTAG was adapted for the development of a novel affinity chromatography method: the SLAPTAG-based affinity chromatography (SAC). Proteins with different molecular weights or biochemical functions were fused in-frame to the SLAPTAG and efficiently purified by a Bacillus subtilis-derived affinity matrix (named Bio-Matrix or BM). Different binding and elution conditions were evaluated to establish an optimized protocol. The binding equilibrium between SLAPTAG and BM was reached after a few minutes of incubation at 4°C, with an apparent dissociation constant (KD) of 4.3μM. A reporter protein (H6-GFP-SLAPTAG) was used to compare SAC protein purification efficiency against commercial immobilized metal affinity chromatography. No differences in protein purification performance were observed between the two methods. The stability and reusability of the BM were evaluated, and it was found that the matrix remained stable for more than a year. BM could be reused up to five times without a significant loss in performance. Additionally, the recovery of bound SLAP-tagged proteins was explored using proteolysis with a SLAP-tagged version of the HRV-3c protease (SLAPASE). This released the untagged GFP while the cut SLAPTAG and the SLAPASE were retained in the BM. As an alternative, iron nanoparticles were linked to the BM, resulting in BMmag. The BMmag was successfully adapted for a magnetic SAC, a technique with potential applications in high-throughput protein production and purification. The SAC protocol can be adapted as a universal tool for the purification of recombinant proteins. Furthermore, the SAC protocol utilizes simple and low-cost reagents, making it suitable for in-house protein purification systems in laboratories worldwide. This enables the production of pure recombinant proteins for research, diagnosis, and the food industry.

Blackstrap molasses as a source of bioactive compounds for the green synthesis of nanoparticles

By-products from the sugar industry (e.g., blackstrap molasses) can be a source of bioactive compounds (e.g., phenolics) known to have antimicrobial, antioxidant, anticancer, and anti-inflammatory properties. These bioactive molecules can be used in the green synthesis of metal nanoparticles. Metal nanoparticles have gathered attention because of their novel physico-chemical properties and potential biological applications (e.g., biocides, fungicides, pesticides, targeted drug and gene delivery, biosensing, medical implants, and plant biostimulants). Gold, silver, iron, and copper nanoparticles are of particular interest as they can be easy to operate and are cost effective, and biocompatible, and their biological activities can be enhanced by surface modifications. In this study, the reducing potential of the phenolic compounds in molasses was investigated for the synthesis of silver nanoparticles without the external addition of reducing agents. The reddish color formation and peak appearance at 420 nm were indications of the successful synthesis of the silver nanoparticles. The synthesized nanoparticles and reducing biomolecules were further characterized by microscopy (SEM, TEM, EDS) and spectroscopy (FTIR) techniques indicating nanoparticles of spherical shape and with particle sizes ranging from 15 nm–45 nm. Their antimicrobial activity was evaluated against several Gram-positive and Gram-negative bacteria. The synthesized nanoparticles showed a biocidal effect, further confirmed by microscopy techniques. It appears that the nanoparticles are interacting with the cell surface of bacteria, penetrating the cell and also causing the disruption of intracellular organelles.

Extraction, Purification, and Chemical Degradation of LPS from Gut Microbiota Strains.

It is estimated that more than 500 different bacterial species colonize the human gut, and they are collectively known as the gut microbiota. Such a massive bacterial presence is now considered an additional organ of the human body, thus becoming the object of an intense and daily growing research activity. Gram-negative bacteria represent a large percentage of the gut microbiota strains. The main constituent of the outer membrane of Gram-negatives is the lipopolysaccharide (LPS). Since its first discovery, LPS has been extensively studied for its structure-dependent capability to elicit a potent immune inflammatory reaction when perceived by specific immune receptors present in our body. Therefore, traditionally, LPS, due to its peculiar chemistry, has been associated with pathogenic bacteria, and it has been extensively studied for its dangerous effects on human health. However, LPS is also expressed on the cell surface of harmless and beneficial bacteria that colonize our intestines. This necessarily implies that the LPS from harmless gut microbes is "chemically different" from that owned by pathogenic ones, hence enabling successful colonization of the intestinal tract without creating a threat to the host immune system. Deciphering the structural features of LPS from these gut bacteria is essential to improve our still scarce knowledge of how the human host lives in a harmonious relationship with its own microbiota. To this end, LPS extraction and purification are essential steps in this field of research. Yet working with gut bacteria is extremely complex for a number of reasons, one being related to the fact that they produce an array of other glycans and glycoconjugates, such as capsular polysaccharides and/or exopolysaccharides, which render the isolation and characterization of the sole LPS not at all trivial. Here, we provide a protocol that might help when dealing with LPS from gut microbial species. We describe the preliminary manipulations and checks, extraction, and purification approaches, as well as the necessary chemical manipulations that should be performed to enable the characterization of the structure of an LPS by means of techniques like nuclear magnetic resonance spectroscopy and mass spectrometry.

Deciphering Molecular Factors That Affect Electron Transfer at the Cell Surface of Electroactive Bacteria: The Case of OmcA from Shewanella oneidensis MR-1

Multiheme cytochromes play a central role in extracellular electron transfer, a process that allows microorganisms to sustain their metabolism with external electron acceptors or donors. In Shewanella oneidensis MR-1, the decaheme cytochromes OmcA and MtrC show functional specificity for interaction with soluble and insoluble redox partners. In this work, the capacity of extracellular electron transfer by mutant variants of S. oneidensis MR-1 OmcA was investigated. The results show that amino acid mutations can affect protein stability and alter the redox properties of the protein, without affecting the ability to perform extracellular electron transfer to methyl orange dye or a poised electrode. The results also show that there is a good correlation between the reduction of the dye and the current generated at the electrode for most but not all mutants. This observation opens the door for investigations of the molecular mechanisms of interaction with different electron acceptors to tailor these surface exposed cytochromes towards specific bio-based applications.

Bioinformatic analysis of WxL domain proteins

The WxL domain is found on the cell surface of many bacteria, most of which are commensal gut bacteria. Its functions are generally identified as being related to virulence and/or peptidoglycan attachment, but there is so far no clear function or structure for this domain. Here, a range of bioinformatics tools were used to clarify the structure and function. These indicate that WxL domains occur in cell surface-associated gene clusters that always contain a small WxL, large WxL and DUF916 domain; and that the small and large WxL proteins have distinct structure despite sharing two conserved WxL motifs. The two WxL motifs form a hydrophobic surface buried inside the protein. The likely function of the WxL domain is to attach to bacterial peptidoglycan, forming a platform to allow associated domains in the cluster to interact with host proteins.

ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF CUTTLEBONE CHITOSAN AGAINST Escherichia coli, Staphylococcus aureus AND Candida albicans

The discovery of new antibiotics for infectious diseases has become challenging due to the rise of antimicrobial resistance.Meanwhile, chitosan has been considerably used in many branches of research. It has been discovered to have some good benefitsin medicals, pharmaceuticals, and food technologies. In this study, chitosan was prepared from the cuttlebone of Sepia sp. bychemical method and analyzed by using FT-IR spectrophotometer for the confirmed presence of its functional groups. Thereare three types of reactive functional groups in the chitosan which are the amino group and primary and secondary hydroxylgroup attached to the C-2, C-3, and C-6 positions respectively. Chitosan has a high cationic property due to the presence of itsamino group. The bacteriostatic activity of chitosan occurs due to its positive charge in acidic concentration that interacts withthe negatively charged residue of carbohydrates, lipids, and proteins located on the cell surface of bacteria. The antioxidantactivity was conducted using DPPH radical scavenging assay with a chitosan concentration ranging from 0.1 to 10 mg/mL anda hydrogen peroxide scavenging assay with a chitosan concentration ranging from 0.1 to 1.6 mg/mL. The antimicrobial activityof chitosan from cuttlebone was analyzed against two different bacterial strains (Escherichia coli & Staphylococcus aureus)and a fungal strain, Candida albicans by disc diffusion and minimum inhibitory concentration (MIC) method. The results showthat through the DPPH radical assay, the scavenging activity was 59.7% at the concentration of chitosan at 10mg/mL, whilethrough the hydrogen peroxide assay the scavenging activity was 56% at the concentration of chitosan at 1.6 mg/mL. Besides,this chitosan from Sepia sp. has concentration-dependent antimicrobial activity with higher antifungal activity compared toantibacterial activity against all tested organisms and may become a potential agent for antibiotic discovery

Effects of genes required for exopolysaccharides biosynthesis in Lacticaseibacillus paracasei S-NB on cell surface characteristics and probiotic properties

The cell surface of lactic acid bacteria (LAB) plays an essential role in cell-cell and cell-host interactions. Exopolysaccharides (EPSs) are produced on the cell surface of LAB or in the surrounding medium and are considered to be in favor of the strain- specific probiotic surface characteristics. In this work, the structure features of EPS from Lacticaseibacillus paracasei S-NB were analyzed preliminarily, and the genes involved in EPS biosynthesis of S-NB strain were hypothesized and annotated, and their role in phenotypic characteristics were demonstrated by gene deletion analysis. Four mutant strains with deletion of crucial genes involved in EPS synthesis were analyzed for strain characteristics that are closely related to their ability to interact with the host intestinal epithelium cells, including strain surface characteristics and viability under the gastrointestinal stress conditions (both acid and bile stress). Furthermore, the adherence and immunomodulatory properties of wild-type S-NB and its mutant strains were compared using Caco-2 and RAW 264.7 cell lines, respectively. Taken together, the results indicated the importance of genes associated with EPS biosynthesis in L. paracasei S-NB as a determinant in strain surface characteristics and cell-host interaction, especially for S-NB_2176 (responsible for EPS polymerization) and S-NB_2175 (responsible for CpsD/CapB family tyrosine-protein kinase).

Influence of electrode surface charge on current production by Geobacter sulfurreducens microbial anodes

Positively charged electrode surfaces are thought to enhance electrostatic interaction with mostly negatively charged bacteria cell surface, thereby improving microbial fuel cell performance. In this work, electrostatic self-assembly of charged polymers was used to systematically modify the surface of indium tin coated electrodes. Evaluation was based on start-up time, maximum current, biofilm thickness and coulombic efficiency of microbial Geobacter sulfurreducens anodes. Coated electrodes were polarized to +0.1 V vs. SHE as biological duplicates. The thickest biofilms and in turn highest current density and shortest start-up time was achieved for negatively charged electrode surfaces like non-coated ITO or polystyrol sulfonate coated electrodes, while positively charged chitosan, negatively charged alginate and positively charged polyethylene imine, in the particular order, produced thinner biofilms, with less current and longer start-up time. This finding contradicted the initial hypothesis. Most experiments on electrode surface modifications are accompanied by an increase in available electrode surface which makes it difficult to extract solely the effect caused by the surface modification. Our study showed the importance of considering also factors other than the surface charge, e.g. potential interactions of the surface modification with the conditioning film and the medium, namely the attraction of cations by a negatively charged surface.

Boron nutrition affects growth, adaptation to stressful environments, and exopolysaccharide synthesis of Ensifer meliloti

Boron (B) is a micronutrient required for the development of symbiotic legume nodules but is apparently not essential for rhizobia, although it has been related to bacteria cell surface formation and adaptation to stress responses. In this paper, we explore whether B nutrition can influence the growth of several strains of Ensifer meliloti (formerly Sinorhizobium meliloti), including mutants defective in exopolysaccharide (EPS) production. All the strains were able to grow in B-deficient (-B) media, except for the non-nodulating Sm11605 mutant, which was unable to produce EPS. The addition of boric acid before the exponential phase of growth (in all strains, including Sm11605) showed that 50 μM H3BO3 (50 B) resulted in the highest growth rate. Moreover, the addition of B increased the tolerance of E. meliloti to salinity (up to 0.5 mM NaCl), to the cell surface stressor SDS (up to 100 μg mL−1 SDS), and to 0.5 mM H2O2. Furthermore, 50 B increased survival rate after 90 min of exposure to 1 mM H2O2, which can be crucial to overcoming transient oxidative burst due to ROS production by root legumes during the initial phases of infection. Given that rhizobia exopolysaccharides (EPSs) are involved in the responses to stress and in the adaptation to and endophytic environment, we hypothesized that B affects EPS production and it can be crucial for growth and survival under stressful environments. Indeed, the amount of EPS extracted from –B cultures was 4–5 times reduced. Gene expression analysis by using qRT-PCR revealed that the genes mucR (a positive regulator of EPS-I but negative regulator of EPS-II synthesis), and emmA (a negative regulator of EPS-I), were overexpressed in –B cells. Meanwhile, expG (a positive regulator of EPS-II), and the genes exoY and expA1 (involved in the synthesis of EPS-I and EPS-II, respectively) were downregulated. These results are consistent with a reduction of both EPS-I and EPS-II synthesis under B deficiency supporting our hypothesis.

Comparative phylogenetic analysis of the Pyruvyltransferase family

Pyruvylation of sugars is a fairly common sugar modification, yet an extensive search of literature reveals little on successful isolations of the enzyme responsible for this sugar modification. Very recently a family of genes have been identified that appear to be involved in pyruvate transfer reactions in prokaryotes. Pyruvate moieties have been identified as one of the important modifications present on cell surfaces of bacteria. These can be utilized in in silico development of antibiotics that are able to target these moieties, and interfere with their biosynthesis, eventually leading to the arrested growth of the bacteria and death in some cases. For this, an in‐depth functional and structural characterization studies is required on the various members of the pyruvyltransferases. In this study we have performed phylogenetic analysis on the pyruvyltransferase family to trace its origin. We have been able to identify three subclasses, and surprisingly this modification is predominantly present in pathogenic bacteria, which can utilized developing a highly targeted antibacterial therapy. Various tools like MEGA and MESQUITE have been used for the analysis.

TP0586532, a non-hydroxamate LpxC inhibitor, reduces LPS release and IL-6 production both in vitro and in vivo.

UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) is an essential enzyme in the biosynthesis of Lipid A, an active component of lipopolysaccharide (LPS), from UDP-3-O-acyl-N-acetylglicosamine. LPS is a major component of the cell surface of Gram-negative bacteria. LPS is known to be one of causative factors of sepsis and has been associated with high mortality in septic shock. TP0586532 is a novel non-hydroxamate LpxC enzyme inhibitor. In this study, we examined the inhibitory effect of TP0586532 on the LPS release from Klebsiella pneumoniae both in vitro and in vivo. Our results confirmed the inhibitory effect of TP0586532 on LPS release from the pathogenic bacterial species. On the other hand, meropenem and ciprofloxacin increase the level of LPS release. Furthermore, the effects of TP0586532 on LPS release and interleukin (IL)-6 production in the lung were determined using a murine model of pneumonia caused by K. pneumoniae. As observed in the in vitro study, TP0586532 showed the marked inhibitory effect on LPS release in the lungs, whereas meropenem- and ciprofloxacin-treated mice showed higher levels of LPS release and IL-6 production in the lungs as compared to those in the lungs of vehicle-treated mice. Moreover, TP0586532 used in combination with meropenem and ciprofloxacin attenuated the LPS release and IL-6 production induced by meropenem and ciprofloxacin in the lung. These results indicate that the inhibitory effect of TP0586532 on LPS release from pathogenic bacteria might be of benefit in patients with sepsis.