Core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in Escherichia coli

2021 ◽  
Author(s):  
Jianli Wang ◽  
Wenjian Ma ◽  
Yu Fang ◽  
Hao Liang ◽  
Huiting Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Cell Envelope ◽  
Gene Clusters ◽  
Gram Negative Bacteria ◽  
Multiple Antibiotic Resistance ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
The Core ◽  
K 12

Gram-negative bacteria are intrinsically resistant to antibiotics due to the presence of the cell envelope, but mechanisms are still not fully understood. In this study, a series of mutants that lack one or more major components associated with the cell envelope were constructed from Escherichia coli K-12 W3110. WJW02 can only synthesize Kdo 2 -lipid A which lacks the core oligosaccharide portion of lipopolysaccharide. WJW04, WJW07 and WJW08 were constructed from WJW02 by deleting the gene clusters relevant to the biosynthesis of exopolysaccharide, flagella and fimbria, respectively. WJW09, WJW010 and WJW011 cells cannot synthesize exopolysaccharide, flagella and fimbria, respectively. Comparing to the wild type W3110, mutants WJW02, WJW04, WJW07 and WJW08 cells showed decreased resistance to more than 10 different antibacterial drugs, but not the mutants WJW09, WJW010 and WJW011. This indicates that the core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in E. coli and the 1 st heptose in core oligosaccharide portion is critical. Furthermore, the removal of the core oligosaccharide of LPS leads to influences on cell wall morphology, cell phenotypes, porins, efflux systems, and the respond behaviors to antibiotic stimulation. The results demonstrated the important role of lipopolysaccharide on the antibiotic resistance of Gram-negative bacteria.

Extended Spectrum Beta Lactamase (ESBL), bla TEM,bla SHVand bla CTX-M,resistance genes in Community and Healthcare Associated Gram Negative Bacteria from Osun State, Nigeria

2020 ◽  
Vol 20 ◽  
Author(s):  
Ganiyat Shitta ◽  
Olufunmilola Makanjuola ◽  
Olusolabomi Adefioye ◽  
Olugbenga Adekunle Olowe
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Multiple Antibiotic Resistance ◽  
Esbl Production ◽  
Gram Negative ◽  
Extended Spectrum Beta Lactamase ◽  
Healthcare Associated ◽  
Esbl Producers

Background: Extended Spectrum Beta Lactamase (ESBL) production in gram negative bacteria confers multiple antibiotic resistance, adversely affecting antimicrobial therapy in infected individuals. ESBLs result from mutations in β-lactamases encoded mainly by the bla TEM,bla SHVand bla CTX-Mgenes. The prevalence of ESBL producing bacteria has been on the increase globally especially its upsurge among isolates from community-acquired infections. Aim: To determine ESBL prevalence and identify ESBL genes among clinical isolates in Osun State, Nigeria. Material and Methods: A cross-sectional study was carried out from August 2016 –July 2017 in Osun State, Nigeria. Three hundred and sixty Gram negative bacteria recovered from clinical samples obtained from both community and healthcare associated infections were tested. They included147 Escherichia coli(40.8%), 116 Klebsiella spp(32.2%), 44 Pseudomo-nas aeruginosa(12.2%) and23 Proteus vulgaris (6.4%) isolates. Others were Acinetobacter baumannii, Serratia rubidae, Citrobacter spp, Enterobacter spp and Salmonella typhi. Disk diffusion antibiotic susceptibility testing was carried out, isolates were screened for ESBL production and confirmed using standard laboratory procedures. ESBLs resistance genes were identified by Polymerase Chain Reaction (PCR). Results: All isolates demonstrated multiple antibiotic resistance. Resistance to ampicillin, amoxicillin with clavulanate and erythromycin was 100%, whereas resistance to Imipenem was very low (5.0%). : Overall prevalence of ESBL producers was 41.4% with Klebsiellaspp as the highest ESBL producing Enterobacteriacaea. ESBL producers were more prevalent among the hospital pathogens than community pathogens, 58% vs 29.5% (p=0.003). ESBL genes were detected in all ESBL producers with the blaCTX-Mgene predominating (47.0%) followed by blaTEM(30.9%) and blaSHVgene was the least, 22.1%. The blaCTX-Mgene was also the most prevalent in the healthcare pathogens (62%) but it accounted for only 25% in those of community origin. Conclusion: A high prevalence of ESBL producing gram negative organisms occurs both in healthcare and in the community in our environment with the CTX-M variant predominating. Efforts to control spread of these pathogens should be addressed.

scholarly journals Gölbaşı ve Azaplı Göllerinden (Adıyaman) İzole Edilen Bakterilerin Tiplendirilmesi ve Çoklu Antibiyotik Dirençliliklerinin Araştırılması

2017 ◽  
Vol 5 (1) ◽  
pp. 43
Author(s):  
Fikret Büyükkaya Kayış ◽  
Sadık Dinçer ◽  
Fatih Matyar ◽  
Hatice Aysun Mercimek Takcı ◽  
Melis Sümengen Özdenefe ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Seasonal Changes ◽  
Reference Value ◽  
Summer Season ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Multiple Antibiotic Resistance ◽  
Disc Diffusion Method ◽  
Gram Negative

Identification and multiple antibiotic resistances of amphicillin, chloramphenicol, streptomycin and tetracycline resistant gram-negative bacteria that isolated microorganisms from Gölbaşı and Azaplı lakes (Adiyaman) were investigated in this study. Seasonally taken isolates of totally 386 bacteria in 10 different species from 7 genera were scanned against 16 antibiotics [gentamycin, imipenem, kanamycin, chloramphenicol, meropenem, nalidixic acid, nitrofurantoin, penicillin, cephalothin, cefazolin, cefpirome, ceftizoxime, cefuroxime, streptomycin, tetracycline and trimethoprim-sulphamethoxazole (Bioanalyse)] by using the disc diffusion method to determine the prevalence of multiple antibiotic resistance. Multiple antibiotic resistance of stations showed seasonal changes between 0.29 and 0.91. In generally, multiple antibiotic resistance in Golbasi and Azapli lakes were higher than the reference value and highest multiple antibiotic resistance values were obtained at summer season (3th period). When the obtained data are considered, high multiple antibiotic resistance poses a risk in terms of public health and for economically important animals.

scholarly journals Degradation of Components of the Lpt Transenvelope Machinery Reveals LPS-Dependent Lpt Complex Stability in Escherichia coli

2021 ◽  
Vol 8 ◽  
Author(s):  
Alessandra M. Martorana ◽  
Elisabete C. C. M. Moura ◽  
Paola Sperandeo ◽  
Flavia Di Vincenzo ◽  
Xiaofei Liang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Envelope ◽  
Barrier Properties ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Complex Stability ◽  
Gram Negative ◽  
Essential Proteins ◽  
Assembly Result ◽  
The Stability

Lipopolysaccharide (LPS) is a peculiar component of the outer membrane (OM) of many Gram-negative bacteria that renders these bacteria highly impermeable to many toxic molecules, including antibiotics. LPS is assembled at the OM by a dedicated intermembrane transport system, the Lpt (LPS transport) machinery, composed of seven essential proteins located in the inner membrane (IM) (LptB2CFG), periplasm (LptA), and OM (LptDE). Defects in LPS transport compromise LPS insertion and assembly at the OM and result in an overall modification of the cell envelope and its permeability barrier properties. LptA is a key component of the Lpt machine. It connects the IM and OM sub-complexes by interacting with the IM protein LptC and the OM protein LptD, thus enabling the LPS transport across the periplasm. Defects in Lpt system assembly result in LptA degradation whose stability can be considered a marker of an improperly assembled Lpt system. Indeed, LptA recruitment by its IM and OM docking sites requires correct maturation of the LptB2CFG and LptDE sub-complexes, respectively. These quality control checkpoints are crucial to avoid LPS mistargeting. To further dissect the requirements for the complete Lpt transenvelope bridge assembly, we explored the importance of LPS presence by blocking its synthesis using an inhibitor compound. Here, we found that the interruption of LPS synthesis results in the degradation of both LptA and LptD, suggesting that, in the absence of the LPS substrate, the stability of the Lpt complex is compromised. Under these conditions, DegP, a major chaperone–protease in Escherichia coli, is responsible for LptD but not LptA degradation. Importantly, LptD and LptA stability is not affected by stressors disturbing the integrity of LPS or peptidoglycan layers, further supporting the notion that the LPS substrate is fundamental to keeping the Lpt transenvelope complex assembled and that LptA and LptD play a major role in the stability of the Lpt system.

scholarly journals An Essential Membrane Protein Modulates the Proteolysis of LpxC to Control Lipopolysaccharide Synthesis in Escherichia coli

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Elayne M. Fivenson ◽  
Thomas G. Bernhardt
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Outer Membrane ◽  
Unknown Function ◽  
Barrier Function ◽  
Major Determinant ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
Essential Protein

ABSTRACT Gram-negative bacteria are surrounded by a complex cell envelope that includes two membranes. The outer membrane prevents many drugs from entering these cells and is thus a major determinant of their intrinsic antibiotic resistance. This barrier function is imparted by the asymmetric architecture of the membrane with lipopolysaccharide (LPS) in the outer leaflet and phospholipids in the inner leaflet. The LPS and phospholipid synthesis pathways share an intermediate. Proper membrane biogenesis therefore requires that the flux through each pathway be balanced. In Escherichia coli, a major control point in establishing this balance is the committed step of LPS synthesis mediated by LpxC. Levels of this enzyme are controlled through its degradation by the inner membrane protease FtsH and its presumed adapter protein LapB (YciM). How turnover of LpxC is controlled has remained unclear for many years. Here, we demonstrate that the essential protein of unknown function YejM (PbgA) participates in this regulatory pathway. Suppressors of YejM essentiality were identified in lpxC and lapB, and LpxC overproduction was shown to be sufficient to allow survival of ΔyejM mutants. Furthermore, the stability of LpxC was shown to be reduced in cells lacking YejM, and genetic and physical interactions between LapB and YejM were detected. Taken together, our results are consistent with a model in which YejM directly modulates LpxC turnover by FtsH-LapB to regulate LPS synthesis and maintain membrane homeostasis. IMPORTANCE The outer membrane is a major determinant of the intrinsic antibiotic resistance of Gram-negative bacteria. It is composed of both lipopolysaccharide (LPS) and phospholipid, and the synthesis of these lipid species must be balanced for the membrane to maintain its barrier function in blocking drug entry. In this study, we identified an essential protein of unknown function as a key new factor in modulating LPS synthesis in the model bacterium Escherichia coli. Our results provide novel insight into how this organism and most likely other Gram-negative bacteria maintain membrane homeostasis and their intrinsic resistance to antibiotics.

scholarly journals The effect of sucrose-induced osmotic stress on the sensitivity of Escherichia coli to bacteriocins

2019 ◽  
Vol 65 (12) ◽  
pp. 895-903 ◽  
Author(s):  
Tatyana Polyudova ◽  
Daria Eroshenko ◽  
Vladimir Korobov
Keyword(s):  
Escherichia Coli ◽  
Osmotic Stress ◽  
Morphological Changes ◽  
Sucrose Solution ◽  
Gram Negative Bacteria ◽  
Lytic Enzymes ◽  
Gram Negative ◽  
E Coli ◽  
Cell Counts ◽  
K 12

Bacteriocins are antimicrobial peptides, produced by Gram-positive bacteria such as lactococci and staphylococci, that have limited bactericidal action against Gram-negative bacteria. The aim of this paper was to study the sensitivity of three strains of Escherichia coli to bacteriocins: nisin (as Nisaplin®) and two staphylococcal peptides (warnerin and hominin) during sucrose-induced osmotic stress. We found that all peptides in a 0.3 g·mL−1 sucrose solution significantly reduced the number of viable E. coli. The most pronounced antibacterial effect was achieved by nisin against E. coli K-12 (3 log reduction). Slightly less bactericidal effects were observed with warnerin (1 mg·mL−1) and hominin (1 mg·mL−1) in sucrose solution. The lytic activity of staphylococcal peptides was detected by decreased optical density and viable cell counts. Moreover, it was confirmed by the increased amount of DNA and protein in the medium and the morphological changes detected by atomic force microscopy after 20 h of treatment. Zymographic analysis revealed the release of lytic enzymes from E. coli cells after treatment with staphylococcal peptides and sucrose. These results indicated that the antimicrobial action of peptides can be extended to Gram-negative bacteria via combination with high concentrations of sucrose.

scholarly journals Bacterial Metal Resistance: Coping with Copper without Cooperativity?

mBio ◽  
2021 ◽  
Author(s):  
Nicholas P. Greene ◽  
Vassilis Koronakis
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Cell Envelope ◽  
Metal Resistance ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Rnd Transporter ◽  
Entire Cell

In Escherichia coli and other Gram-negative bacteria, tripartite efflux pumps (TEPs) span the entire cell envelope and serve to remove noxious molecules from the cell. CusBCA is a TEP responsible for copper and silver detoxification in E. coli powered by the resistance-nodulation-cell division (RND) transporter, CusA.

scholarly journals Lipopolysaccharide transport involves long-range coupling between cytoplasmic and periplasmic domains of the LptB2FGC extractor

2020 ◽  
Author(s):  
Emily A. Lundstedt ◽  
Brent W. Simpson ◽  
Natividad Ruiz
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Outer Membrane ◽  
Permeability Barrier ◽  
Core Oligosaccharide ◽  
Inner Membrane ◽  
Gram Negative ◽  
The Core ◽  
Directional Coupling ◽  
Binding Cavity

The cell surface of the Gram-negative cell envelope contains lipopolysaccharide (LPS) molecules, which form a permeability barrier against hydrophobic antibiotics. The LPS transport (Lpt) machine composed of LptB2FGCADE forms a proteinaceous trans-envelope bridge that allows for the rapid and specific transport of newly synthesized LPS from the inner membrane (IM) to the outer membrane (OM). This transport is powered from the IM by the ATP-binding cassette transporter LptB2FGC. The ATP-driven cycling between closed- and open-dimer states of the ATPase LptB2 is coupled to the extraction of LPS by the transmembrane domains LptFG. However, the mechanism by which LPS moves from a substrate-binding cavity formed by LptFG at the IM to the first component of the periplasmic bridge, the periplasmic β-jellyroll domain of LptF, is poorly understood. To better understand how LptB2FGC functions in Escherichia coli, we searched for suppressors of a defective LptB variant. We found that defects in LptB2 can be suppressed by both structural modifications to the core oligosaccharide of LPS and changes in various regions of LptFG, including a periplasmic loop in LptF that connects the substrate-binding cavity in LptFG to the periplasmic β-jellyroll domain of LptF. These novel suppressors suggest that interactions between the core oligosaccharide of LPS and periplasmic regions in the transporter influence the rate of LPS extraction by LptB2FGC. Together, our genetic data reveal a path for the bi-directional coupling between LptB2 and LptFG that extends from the cytoplasm to the entrance to the periplasmic bridge of the transporter. IMPORTANCE Gram-negative bacteria are intrinsically resistant to many antibiotics due to the presence of lipopolysaccharide (LPS) at their cell surface. LPS is transported from its site of synthesis at the inner membrane to the outer membrane by the Lpt machine. Lpt proteins form a transporter that spans the entire envelope and is thought to function similarly to a PEZ candy dispenser. This trans-envelope machine is powered by the cytoplasmic LptB ATPase through a poorly understood mechanism. Using genetic analyses in Escherichia coli, we found that LPS transport involves long-ranging bi-directional coupling across cellular compartments between cytoplasmic LptB and periplasmic regions of the Lpt transporter. This knowledge could be exploited in developing antimicrobials that overcome the permeability barrier imposed by LPS.

scholarly journals An essential membrane protein modulates the proteolysis of LpxC to control lipopolysaccharide synthesis in Escherichia coli

2020 ◽  
Author(s):  
Elayne M. Fivenson ◽  
Thomas G. Bernhardt
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Outer Membrane ◽  
Unknown Function ◽  
Barrier Function ◽  
Adaptor Protein ◽  
Major Determinant ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Essential Protein

ABSTRACTGram-negative bacteria are surrounded by a complex cell envelope that includes two membranes. The outer membrane prevents many drugs from entering these cells and is thus a major determinant of their intrinsic antibiotic resistance. This barrier function is imparted by the asymmetric architecture of the membrane with lipopolysaccharide (LPS) in the outer leaflet and phospholipids in the inner leaflet. The LPS and phospholipid synthesis pathways share a common intermediate. Proper membrane biogenesis therefore requires that the flux through each pathway be balanced. In Escherichia coli, a major control point in establishing this balance is the committed step of LPS synthesis mediated by LpxC. Levels of this enzyme are controlled through its degradation by the inner membrane protease FtsH and its presumed adaptor protein LapB(YciM). How turnover of LpxC is controlled has remained unclear for many years. Here, we demonstrate that the essential protein of unknown function YejM(PbgA), which we have renamed ClxD (control of LpxC degradation), participates in this regulatory pathway. Suppressors of ClxD essentiality were identified in lpxC and lapB, and LpxC overproduction was shown to be sufficient to allow survival of ΔclxD mutants. Furthermore, the half-life of LpxC was shown to be reduced in cells lacking ClxD, and genetic and physical interactions between LapB and ClxD were detected. Taken together, our results are consistent with a model in which ClxD directly modulates LpxC turnover by FtsH-LapB to regulate LPS synthesis and maintain membrane homeostasis.SIGNIFICANCEThe outer membrane is a major determinant of the intrinsic antibiotic resistance of Gram-negative bacteria. It is composed of both lipopolysaccharide (LPS) and phospholipid, and the synthesis of these lipid species must be balanced for the membrane to maintain its barrier function in blocking drug entry. In this report, we identify an essential protein of unknown function as a key new factor in maintaining LPS/phospholipid balance in the model bacterium Escherichia coli. Our results provide novel insight into how this organism and most likely other Gram-negative bacteria maintain membrane homeostasis and their intrinsic resistance to antibiotics.

Isolation and characterization of 3-acetamido-3,6-dideoxy-L-glucose from the core oligosaccharides obtained from the aquatic gram-negative bacteria Aeromonas hydrophila and Vibrio anguillarum

1981 ◽  
Vol 59 (11-12) ◽  
pp. 877-879 ◽  
Author(s):  
Joseph H. Banoub ◽  
Derek H. Shaw
Keyword(s):  
Aeromonas Hydrophila ◽  
Vibrio Anguillarum ◽  
Amino Sugar ◽  
Gram Negative Bacteria ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
The Core ◽  
Isolation And Characterization ◽  
Bacterial Lipopolysaccharides

The amino sugar 3-acetamido-3,6-dideoxy-L-glucose has been isolated and characterized from the core oligosaccharide obtained from the bacterial lipopolysaccharides of Aeromonas hydrophila and Vibrio anguillarum. This is the first occasion in which a dideoxyamino sugar has been confirmed as a constituent of the core oligosaccharide rather than the O-polysaccharide.

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