scholarly journals Capsular Polysaccharide Is a Receptor of a Clostridium perfringens Bacteriophage CPS1

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1002 ◽  
Author(s):  
Eunsu Ha ◽  
Jihwan Chun ◽  
Minsik Kim ◽  
Sangryeol Ryu
Keyword(s):  
Clostridium Perfringens ◽  
Pathogenic Bacteria ◽  
Capsular Polysaccharide ◽  
Capsular Polysaccharides ◽  
Foodborne Illnesses ◽  
Gene Encoding ◽  
Antibiotic Resistant ◽  
Common Causes ◽  
Biochemical Analyses ◽  
Tn5 Mutant

Clostridium perfringens is a Gram-positive, anaerobic, and spore forming bacterium that is widely distributed in the environment and one of the most common causes of foodborne illnesses. Bacteriophages are regarded as one of the most promising alternatives to antibiotics in controlling antibiotic-resistant pathogenic bacteria. Here we isolated a virulent C. perfringens phage, CPS1, and analysis of its whole genome and morphology revealed a small genome (19 kbps) and a short noncontractile tail, suggesting that CPS1 can be classified as a member of Picovirinae, a subfamily of Podoviridae. To determine the host receptor of CPS1, the EZ-Tn5 random transposon mutant library of C. perfringens ATCC 13124 was constructed and screened for resistance to CPS1 infection. Analysis of the CPS1-resistant mutants revealed that the CPF_0486 was disrupted by Tn5. The CPF_0486 was annotated as galE, a gene encoding UDP-glucose 4-epimerase (GalE). However, biochemical analyses demonstrated that the encoded protein possessed dual activities of GalE and UDP-N-acetylglucosamine 4-epimerase (Gne). We found that the CPF_0486::Tn5 mutant produced a reduced amount of capsular polysaccharides (CPS) compared with the wild type. We also discovered that glucosamine and galactosamine could competitively inhibit host adsorption of CPS1. These results suggest that CPS acts as a receptor for this phage.

scholarly journals A Structural Model for the Ligand Binding of Pneumococcal Serotype 3 Capsular Polysaccharide-Specific Protective Antibodies

mBio ◽  
2021 ◽  
Author(s):  
Ahmet Ozdilek ◽  
Jiachen Huang ◽  
Rachelle Babb ◽  
Amy V. Paschall ◽  
Dustin R. Middleton ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Structural Model ◽  
Capsular Polysaccharide ◽  
Capsular Polysaccharides ◽  
Bacterial Diseases ◽  
Major Threat ◽  
Protective Antibodies ◽  
Pneumococcal Serotype ◽  
Glycoconjugate Vaccines ◽  
Main Components

Infectious diseases caused by pathogenic bacteria are a major threat to human health. Capsular polysaccharides (CPSs) of many pathogenic bacteria have been used as the main components of glycoconjugate vaccines against bacterial diseases in clinical practice worldwide, with various degrees of success.

scholarly journals Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

2021 ◽  
Vol 17 ◽  
pp. 2915-2921
Author(s):  
Tanmoy Halder ◽  
Somnath Yadav
Keyword(s):  
Total Synthesis ◽  
Pathogenic Bacteria ◽  
Capsular Polysaccharides ◽  
One Pot ◽  
Antibiotic Resistant ◽  
O Antigen ◽  
The Family ◽  
Providencia Stuartii ◽  
The One ◽  
Tract Infections

Capsular polysaccharides of pathogenic bacteria have been reported to be effective vaccines against diseases caused by them. Providencia stuartii is a class of enterobacteria of the family Providencia that is responsible for several antibiotic resistant infections, particularly urinary tract infections of patients with prolonged catheterization in hospital settings. Towards the goal of development of vaccine candidates against this pathogen, we herein report the total synthesis of a trisaccharide repeating unit of the O-antigen polysaccharide of the P. stuartii O49 serotype containing the →6)-β-ᴅ-Galp-(1→3)-β-ᴅ-GalpNAc(1→4)-α-ᴅ-Galp(1→ linkage. The synthesis of the trisaccharide repeating unit was carried out first by a linear strategy involving the [1 + (1 + 1 = 2)] assembly, followed by a one-pot synthesis involving [1 + 1 + 1] strategy from the corresponding monosaccharides. The one-pot method provided a higher yield of the protected trisaccharide intermediate (73%) compared to the two step synthesis (66%). The protected trisaccharide was then deprotected and N-acetylated to finally afford the desired trisaccharide repeating unit as its α-p-methoxyphenyl glycoside.

scholarly journals Membrane linkage of a Streptococcus pneumoniae Wzy capsular polysaccharide occurs through an acylglycerol

2020 ◽  
Author(s):  
Thomas R. Larson ◽  
Janet Yother
Keyword(s):  
Streptococcus Pneumoniae ◽  
Pathogenic Bacteria ◽  
Capsular Polysaccharide ◽  
Repeat Unit ◽  
Capsular Polysaccharides ◽  
Outer Face ◽  
Gram Positive ◽  
Bacterial Surface ◽  
Gram Positive Bacteria ◽  
Undecaprenyl Phosphate

ABSTRACTCapsular polysaccharides (capsules) protect bacteria from environmental insults and can contribute to virulence in pathogenic bacteria. Their appropriate display on the bacterial surface is critical to their functions. In Gram-positive bacteria, most capsules are synthesized by the Wzy polymerase-dependent pathway, which is also utilized in the synthesis of many capsules and O-antigens of Gram-negative bacteria. Synthesis of capsule repeat units initiates on undecaprenyl-phosphate on the inner face of the cytoplasmic membrane, with polymerization occurring on the outer face of the membrane. In Gram-positive bacteria, the capsule can be transferred to peptidoglycan, as in Streptococcus pneumoniae where a direct glycosidic bond to the peptidoglycan N-acetylglucosamine occurs. In S. pneumoniae, capsule can also be detected on the membrane, and this has generally been assumed to reflect polysaccharide that is linked to undecaprenyl-phosphate and in the process of synthesis. We provide evidence here, however, that final membrane linkage occurs through an acylglycerol, and essentially all of the polysaccharide is transferred from the initial undecaprenyl-phosphate acceptor to an alternate acceptor. This step allows for recycling of undecaprenyl-phosphate and represents an additional terminal step in capsule synthesis. In this regard, capsule synthesis resembles that of the wall- and lipoteichoic acids of S. pneumoniae, wherein a common repeat unit and polymer structure are synthesized by the Wzy pathway with divergence at the terminal step that results in linkages to peptidoglycan and a membrane acylglycerol anchor.IMPORTANCELinkage of capsular polysaccharides to the bacterial cell surface is a critical step in assuring the ability of these polymers to fulfill their functions, such as the resistance to complement-mediated phagocytosis that can be essential for pathogenic organisms to survive in host environments. Knowledge of the mechanisms by which these linkages occur is incomplete. In this study, we provide evidence for linkage of an S. pneumoniae Wzy capsule to an acylglycerol, the most abundant class of lipids in the membrane. This linkage provides a terminal acceptor for capsule that occurs in addition to that of peptidoglycan. Transfer to these terminal receptors is an essential step in CPS synthesis, as failure to do so can be lethal for the cell.

scholarly journals Mutation in the ntrR Gene, a Member of the vap Gene Family, Increases the Symbiotic Efficiency of Sinorhizobium meliloti

2001 ◽  
Vol 14 (7) ◽  
pp. 887-894 ◽  
Author(s):  
Boglárka Oláh ◽  
Erno Kiss ◽  
Zoltán Györgypál ◽  
Judit Borzi ◽  
Gyöngyi Cinege ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Pathogenic Bacteria ◽  
Sinorhizobium Meliloti ◽  
Root Nodules ◽  
Nifh Gene ◽  
Dry Weight ◽  
Nodule Occupancy ◽  
Gene Encoding ◽  
Symbiotic Efficiency ◽  
Host Interactions

In specific plant organs, namely the root nodules of alfalfa, fixed nitrogen (ammonia) produced by the symbiotic partner Sinorhizobium meliloti supports the growth of the host plant in nitrogen-depleted environment. Here, we report that a derivative of S. meliloti carrying a mutation in the chromosomal ntrR gene induced nodules with enhanced nitrogen fixation capacity, resulting in an increased dry weight and nitrogen content of alfalfa. The efficient nitrogen fixation is a result of the higher expression level of the nifH gene, encoding one of the subunits of the nitrogenase enzyme, and nifA, the transcriptional regulator of the nif operon. The ntrR gene, controlled negatively by its own product and positively by the symbiotic regulator syrM, is expressed in the same zone of nodules as the nif genes. As a result of the nitrogen-tolerant phenotype of the strain, the beneficial effect of the mutation on efficiency is not abolished in the presence of the exogenous nitrogen source. The ntrR mutant is highly competitive in nodule occupancy compared with the wild-type strain. Sequence analysis of the mutant region revealed a new cluster of genes, termed the “ntrPR operon,” which is highly homologous to a group of vap-related genes of various pathogenic bacteria that are presumably implicated in bacterium-host interactions. On the basis of its favorable properties, the strain is a good candidate for future agricultural utilization.

scholarly journals Bacteria and Their Antibiotic Resistance Profiles in Ambient Air in Accra, Ghana, February 2020: A Cross-Sectional Study

2021 ◽  
Vol 6 (3) ◽  
pp. 110
Author(s):  
Godfred Saviour Kudjo Azaglo ◽  
Mohammed Khogali ◽  
Katrina Hann ◽  
John Alexis Pwamang ◽  
Emmanuel Appoh ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Pathogenic Bacteria ◽  
Ambient Air ◽  
Cross Sectional Study ◽  
Bacillus Species ◽  
Resistant Bacteria ◽  
Cross Sectional ◽  
Antibiotic Resistant ◽  
Bacterial Counts ◽  
Inappropriate Use

Inappropriate use of antibiotics has led to the presence of antibiotic-resistant bacteria in ambient air. There is no published information about the presence and resistance profiles of bacteria in ambient air in Ghana. We evaluated the presence and antibiotic resistance profiles of selected bacterial, environmental and meteorological characteristics and airborne bacterial counts in 12 active air quality monitoring sites (seven roadside, two industrial and three residential) in Accra in February 2020. Roadside sites had the highest median temperature, relative humidity, wind speed and PM10 concentrations, and median airborne bacterial counts in roadside sites (115,000 CFU/m3) were higher compared with industrial (35,150 CFU/m3) and residential sites (1210 CFU/m3). Bacillus species were isolated in all samples and none were antibiotic resistant. There were, however, Pseudomonas aeruginosa, Escherichia coli, Pseudomonas species, non-hemolytic Streptococci, Coliforms and Staphylococci species, of which six (50%) showed mono-resistance or multidrug resistance to four antibiotics (penicillin, ampicillin, ciprofloxacin and ceftriaxone). There was a positive correlation between PM10 concentrations and airborne bacterial counts (rs = 0.72), but no correlations were found between PM10 concentrations and the pathogenic bacteria nor their antibiotic resistance. We call for the expansion of surveillance of ambient air to other cities of Ghana to obtain nationally representative information.

scholarly journals Effects of Growth Phase and Extracellular Slime on Photodynamic Inactivation of Gram-Positive Pathogenic Bacteria

2004 ◽  
Vol 48 (6) ◽  
pp. 2173-2178 ◽  
Author(s):  
Faten Gad ◽  
Touqir Zahra ◽  
Tayyaba Hasan ◽  
Michael R. Hamblin
Keyword(s):  
Stationary Phase ◽  
Pathogenic Bacteria ◽  
Capsular Polysaccharide ◽  
Photodynamic Inactivation ◽  
Wild Type ◽  
Gram Positive ◽  
Slime Production ◽  
Subsequent Exposure ◽  
Cationic Compounds ◽  
Extracellular Slime

ABSTRACT The emergence of antibiotic resistance among pathogenic bacteria has led to efforts to find alternative antimicrobial therapeutics to which bacteria will not be easily able to develop resistance. One of these may be the combination of nontoxic dyes (photosensitizers [PS]) and visible light, known as photodynamic therapy, and we have reported its use to treat localized infections in animal models. While it is known that gram-positive species are generally susceptible to photodynamic inactivation (PDI), the factors that govern variation in degrees of killing are unknown. We used isogenic pairs of wild-type and transposon mutants deficient in capsular polysaccharide and slime production generated from Staphylococcus epidermidis and Staphylococcus aureus to examine the effects of extracellular slime on susceptibility to PDI mediated by two cationic PS (a polylysine-chlorin e6 conjugate, pL-c e6 , and methylene blue [MB]) and an anionic molecule, free c e6 , and subsequent exposure to 665-nm light at 0 to 40 J/cm2. Free c e6 gave more killing of mutant strains than wild type, despite the latter taking up more PS. Log-phase cultures were killed more than stationary-phase cultures, and this correlated with increased uptake. The cationic pL-c e6 and MB gave similar uptakes and killing despite a 50-fold difference in incubation concentration. Differences in susceptibility between strains and between growth phases observed with free c e6 largely disappeared with the cationic compounds despite significant differences in uptake. These data suggest that slime production and stationary phase can be obstacles against PDI for gram-positive bacteria but that these obstacles can be overcome by using cationic PS.

Antibiotic susceptibility pattern against pathogenic bacteria causing Dental Caries

2011 ◽  
Vol 1 (1) ◽  
pp. 31-35
Author(s):  
Deepak Dwivedi ◽  
Tejram Kushwah ◽  
Mukesh Kushwah ◽  
Vinod Singh
Keyword(s):  
Dental Caries ◽  
Antibiotic Susceptibility ◽  
Pathogenic Bacteria ◽  
Resistant Bacteria ◽  
Susceptibility Pattern ◽  
Antibiotic Resistant ◽  
Antibiotic Susceptibility Pattern ◽  
Penicillin V ◽  
Antibiotics Susceptibility ◽  
Susceptibility Tests

Antibiotics to treat dental caries infection are routinely prescribed which led to the increased resistance against bacteria. The purpose of this investigation was to perform antibiotic susceptibility tests on a panel of pathogenic bacteria isolated from dental caries infection. Bacteria were isolated from caries site of patients and identified at the species level. Each of 150 species of bacteria was tested for antibiotics susceptibility to a five antibiotics using Etest. The antibiotics used were Amoxicillin, Cloxocillin, Erythromycin, Tetracycline and Penicillin‐V. The obtained resistance percentage for each antibiotic were Penicillin V: 72/150 (48%), Tetracycline: 99/150 (66%), Amoxicillin: 135/150 (90%), Cloxocillin: 117/150 (78%), and Erythromycin: 90/150 (60%) (Table 1). In case of combinatorial antibiotic exposure, the resistance percentage of Penicillin V/Amoxicillin and Amoxicillin/ Erythromycin was 39/150 (26%), and 45/150 (30%) respectively. The study has well demonstrated the clinical picture of antibiotic resistance and susceptibility pattern of bacteria causing dental caries. The obtained comprehensive data will allow investigating the spatial distribution of pathogenic, antibiotic resistant bacteria among dental caries patients which further may help into development of novel diagnostic and treatment approaches for the same.

Implant Infections Due to Enterococci: Role of Capsular Polysaccharides and Biofilm

2005 ◽  
Vol 28 (11) ◽  
pp. 1079-1090 ◽  
Author(s):  
F. Fabretti ◽  
J. Huebner
Keyword(s):  
Antimicrobial Agents ◽  
Capsular Polysaccharide ◽  
Female Genital Tract ◽  
Teichoic Acid ◽  
Capsular Polysaccharides ◽  
Human Pathogens ◽  
Artificial Joints ◽  
Artificial Hearts ◽  
Intravascular Catheters ◽  
Enterococcal Infections

Enterococci are natural inhabitants of the gastrointestinal tract and of the female genital tract of humans and many animals. In recent years, enterococci have been increasingly recognized as important human pathogens causing infections associated with medical devices. Their resistance to most antimicrobial agents and their ability to form biofilm has contributed to the increasing incidence of nosocomial enterococcal infections. Enterococci possess a capsular polysaccharide composed of a glycerol-teichoic acid-like molecule consisting of repeating units of 6-α-D-glucose-1-2-glycerol-3-PO4, substituted on carbon 2 with a α-2,1-linked molecule of glucose. Using both immunologic and genetic data E. faecalis can be assigned to specific serotypes based on capsular polysaccharides. Clinical examples of foreign-body infections due to enterococci are described, comprising infections of artificial joints, implanted intravascular catheters, artificial hearts and artificial valves, stents, liquor shunt devices, and intraocular infections. Methods to prevent and/or treat enterococcal infections are presented.

scholarly journals Bacteriophages: the possible solution to treat infections caused by pathogenic bacteria

2017 ◽  
Vol 63 (11) ◽  
pp. 865-879 ◽  
Author(s):  
Ayman El-Shibiny ◽  
Salma El-Sahhar
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Phage Therapy ◽  
Multidrug Resistant ◽  
Clinical Applications ◽  
Western World ◽  
Resistant Bacteria ◽  
Vaccine Production ◽  
Bacterial Populations ◽  
Antibiotic Resistant

Since their discovery in 1915, bacteriophages have been used to treat bacterial infections in animals and humans because of their unique ability to infect their specific bacterial hosts without affecting other bacterial populations. The research carried out in this field throughout the 20th century, largely in Georgia, part of USSR and Poland, led to the establishment of phage therapy protocols. However, the discovery of penicillin and sulfonamide antibiotics in the Western World during the 1930s was a setback in the advancement of phage therapy. The misuse of antibiotics has reduced their efficacy in controlling pathogens and has led to an increase in the number of antibiotic-resistant bacteria. As an alternative to antibiotics, bacteriophages have become a topic of interest with the emergence of multidrug-resistant bacteria, which are a threat to public health. Recent studies have indicated that bacteriophages can be used indirectly to detect pathogenic bacteria or directly as biocontrol agents. Moreover, they can be used to develop new molecules for clinical applications, vaccine production, drug design, and in the nanomedicine field via phage display.

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