scholarly journals The sentinel role of peptidoglycan recycling in the β-lactam resistance of the Gram-negative Enterobacteriaceae and Pseudomonas aeruginosa

2014 ◽  
Vol 56 ◽  
pp. 41-48 ◽  
Author(s):  
Jed F. Fisher ◽  
Shahriar Mobashery
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gram Negative

scholarly journals MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa

2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Cell Division ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Active Efflux

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Gram Negative Bacteria ◽  
Normal Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

Molybdenum Binding by Pseudomonas aeruginosa

1986 ◽  
Vol 39 (8) ◽  
pp. 1205 ◽  
Author(s):  
S Stojkovski ◽  
RJ Magee ◽  
J Liesegang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Uronic Acid ◽  
Extracellular Polysaccharide ◽  
Uronic Acids ◽  
Negative Bacterium ◽  
Molybdenum Complex ◽  
Gram Negative ◽  
Pseudomonas Aeruginosa Pao1 ◽  
Polysaccharide Layer

The uptake of molybdenum by certain bacteria hinders its role as a trace metal in the micronutrients for plant growth. The binding of molybdenum by the Gram-negative bacterium Pseudomonas aeruginosa, PAO1, has been investigated. A molybdenum complex of uronic acid, which forms in the extracellular polysaccharide layer (slime), was isolated and characterized by a variety of techniques. Comparisons with 'mimic' compounds of uronic acids suggest that Pseudomonas aeruginosa, PAO1, produces a binuclear, di-oxo-bridged magnesium salt MgMo2O4(C6H8O7)2.5H2O; this indicates the important role of uronic acids in metallic uptake by bacteria.

Accumulation of copper and silver onto cell body and its effect on the inactivation of Pseudomonas aeruginosa

2006 ◽  
Vol 54 (3) ◽  
pp. 29-34 ◽  
Author(s):  
M.G. Hwang ◽  
H. Katayama ◽  
S. Ohgaki
Keyword(s):  
Flow Cytometry ◽  
Pseudomonas Aeruginosa ◽  
Drinking Water ◽  
High Tolerance ◽  
Gram Negative ◽  
Syto 9 ◽  
Relationship Of ◽  
The Relationship ◽  
Specific Amount

Pseudomonas aeruginosa, a gram-negative rod bacterium, is a causative agent of waterborne pneumonia and presents high tolerance against conventional disinfectants. The inorganic biocidal reagents, copper and silver, were applied to inactivate P. aeruginosa inoculated in a synthetic drinking water (SDW). Additionally, the relationship of the specific amount of accumulated copper and silver reagents (Cs) on P. aeruginosa with inactivation profile was elucidated in this study. Flow cytometry (FCM) following staining with SYTO 9 and PI was used for detection of bacterial viability and density. Individual copper and silver reagents, and their combination, exhibited excellent biocidal abilities even at the concentration of 0.05 mgCu/L and 0.005 mgAg/L. The critical amounts of accumulated disinfectant (Cs) were calculated at 2.82×10−7 μgCu/cellsi and 5.13×10−8 μgAg/cellsi at an incubation of 70 h. Consequently, the role of disinfectant on the inactivation of P. aeruginosa and the assessment of biocidal ability of copper, silver, and their combination were successfully explained by evaluating the terms Cs and Cc.

scholarly journals Relationship between Biofilm Regulating Operons and Various Β-Lactamase Enzymes: Analysis of the Clinical Features of Infections caused by Non-Fermentative Gram-Negative Bacilli (Nfgnb) from Iran

2020 ◽  
Vol 14 (3) ◽  
pp. 1723-1736
Author(s):  
Mahyar Porbaran ◽  
Reza Habibipour
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acinetobacter Baumannii ◽  
Clinical Features ◽  
Resistance Genes ◽  
Clinical Samples ◽  
Gram Negative ◽  
Pcr Method ◽  
Regulator Genes ◽  
High Doses

Bacteria are capable of evolving high doses of the drug in various infections by forming biofilms. Perhaps, biofilm regulator genes have different frequencies in β-lactam producing non-fermentative Gram-negative Bacilli (NFGNB). In this study, we investigated the role of biofilm operons of Pseudomonas aeruginosa and Acinetobacter baumannii on the prevalence of different β-lactamase enzymes. One-hundred twenty (120) nosocomial NFGNB isolates were collected from different clinical samples of patients. PCR method was used for the amplification of resistance genes. Isolates were collected, including 50 isolates (41.66%) of P. aeruginosa and 70 isolates (58.33%) of A. baumannii. The distribution of ESBL, AmpC, KPC, and MBL β-lactamase enzymes in P. aeruginosa and A. baumannii isolates were 64%, 58%, 38%,44%, and 57.14%, 60%, 32.85%, 34.28%, respectively. The frequency of csuABC, pgaABC operon in A. baumannii were as follows: pgaA (45.71%), pgaB (32.85%), pgaC (42.85%), csuA (34.28%), csuB (32.85%), csuC (41.42%), and ompA (38.57%). Further, the prevalence of pslABC and pelABC operons in P. aeruginosa isolates were as follows: pslA (58%), pslB (58%), pslD (60%), pelA (64%), pelB (38%), pelC (44%), and algD (68%). This study revealed that the abundance of biofilm regulator genes in NFGNB strains is affected by different β-lactamase enzymes.

scholarly journals Inactivation of the Glycoside Hydrolase NagZ Attenuates Antipseudomonal β-Lactam Resistance in Pseudomonas aeruginosa

2009 ◽  
Vol 53 (6) ◽  
pp. 2274-2282 ◽  
Author(s):  
Azizah Asgarali ◽  
Keith A. Stubbs ◽  
Antonio Oliver ◽  
David J. Vocadlo ◽  
Brian L. Mark
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glycoside Hydrolase ◽  
Null Mutant ◽  
Gram Negative ◽  
Molecule Inhibitor ◽  
Clinical Resistance ◽  
Gram Negative Organisms ◽  
Null Mutants ◽  
Selection Of

ABSTRACT The overproduction of chromosomal AmpC β-lactamase poses a serious challenge to the successful treatment of Pseudomonas aeruginosa infections with β-lactam antibiotics. The induction of ampC expression by β-lactams is mediated by the disruption of peptidoglycan (PG) recycling and the accumulation of cytosolic 1,6-anhydro-N-acetylmuramyl peptides, catabolites of PG recycling that are generated by an N-acetyl-β-d-glucosaminidase encoded by nagZ (PA3005). In the absence of β-lactams, ampC expression is repressed by three AmpD amidases encoded by ampD, ampDh2, and ampDh3, which act to degrade these 1,6-anhydro-N-acetylmuramyl peptide inducer molecules. The inactivation of ampD genes results in the stepwise upregulation of ampC expression and clinical resistance to antipseudomonal β-lactams due to the accumulation of the ampC inducer anhydromuropeptides. To examine the role of NagZ on AmpC-mediated β-lactam resistance in P. aeruginosa, we inactivated nagZ in P. aeruginosa PAO1 and in an isogenic triple ampD null mutant. We show that the inactivation of nagZ represses both the intrinsic β-lactam resistance (up to 4-fold) and the high antipseudomonal β-lactam resistance (up to 16-fold) that is associated with the loss of AmpD activity. We also demonstrate that AmpC-mediated resistance to antipseudomonal β-lactams can be attenuated in PAO1 and in a series of ampD null mutants using a selective small-molecule inhibitor of NagZ. Our results suggest that the blockage of NagZ activity could provide a strategy to enhance the efficacies of β-lactams against P. aeruginosa and other gram-negative organisms that encode inducible chromosomal ampC and to counteract the hyperinduction of ampC that occurs from the selection of ampD null mutations during β-lactam therapy.

EVALUATION THE EFFECT OF PRODIGIOSIN ON ALGD EXPRESSION IN CLINICAL ISOLATES OF PSEUDOMONAS AERUGINOSA

2021 ◽  
Vol 74 (9) ◽  
pp. 2265-2276
Author(s):  
Safiya Saad Dhaif ◽  
Nagham Shakir Al-Attar
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Inhibitory Concentration ◽  
Bacterial Isolates ◽  
Quantitative Real Time Pcr ◽  
Biochemical Tests ◽  
Gram Negative ◽  
Vitek 2

The aim of this study is to investigate the role of prodigiosin on P. aeruginosa' s biofilm genes involved in the pathogenicity and persistency of the bacteria; Materials and methods: Gram negative bacterial isolates were taken from burn and wounds specimen obtained from some of Baghdad hospitals. Forty six isolates were identified as Pseudomonas aeruginosa and four isolates as Serratia marcescens by using biochemical tests and VITEK 2 compact system. Susceptibility test was performed for all P. aeruginosa isolates, the results showed that 100% were resistant to Amikacin and 98% were sensitive to Meropenem. Resistant isolates were tested for biofilm formation; the strong and moderate isolates (17) were detected by PCR for AlgD gene presence. From 17 isolates only two had AlgD gene. All serratia isolates were screened for prodigiosin production, which were extracted from the best producer isolate. Minimal inhibitory concentration was assessed for prodigiosin and ciprofloxacin and synergism between them against the two isolates of P. aeruginosa. Results and conclusions: The results showed that the synergistic effect decreased MIC of both prodigiosin and ciprofloxacin by combination, and reduction of biofilm formation was detected. RNA was extracted from the two selected isolates as control in addition to three treatments. The result of quantitative real time PCR showed down regulation in the AlgD gene expression level under some treatments, while there was no gene expression in most treatments with both sub-MICs treatment

scholarly journals Effect of rpoS Mutation on the Stress Response and Expression of Virulence Factors in Pseudomonas aeruginosa

1999 ◽  
Vol 181 (13) ◽  
pp. 3890-3897 ◽  
Author(s):  
Sang-Jin Suh ◽  
Laura Silo-Suh ◽  
Donald E. Woods ◽  
Daniel J. Hassett ◽  
Susan E. H. West ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stress Response ◽  
Parent Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Infection Model ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Gram Negative

ABSTRACT The sigma factor RpoS (ςS) has been described as a general stress response regulator that controls the expression of genes which confer increased resistance to various stresses in some gram-negative bacteria. To elucidate the role of RpoS inPseudomonas aeruginosa physiology and pathogenesis, we constructed rpoS mutants in several strains of P. aeruginosa, including PAO1. The PAO1 rpoS mutant was subjected to various environmental stresses, and we compared the resistance phenotype of the mutant to that of the parent. The PAO1rpoS mutant was slightly more sensitive to carbon starvation than the wild-type strain, but this phenotype was obvious only when the cells were grown in a medium supplemented with glucose as the sole carbon source. In addition, the PAO1 rpoS mutant was hypersensitive to heat shock at 50°C, increased osmolarity, and prolonged exposure to high concentrations of H2O2. In accordance with the hypersensitivity to H2O2, catalase production was 60% lower in the rpoS mutant than in the parent strain. We also assessed the role of RpoS in the production of several exoproducts known to be important for virulence of P. aeruginosa. TherpoS mutant produced 50% less exotoxin A, but it produced only slightly smaller amounts of elastase and LasA protease than the parent strain. The levels of phospholipase C and casein-degrading proteases were unaffected by a mutation in rpoS in PAO1. The rpoS mutation resulted in the increased production of the phenazine antibiotic pyocyanin and the siderophore pyoverdine. This increased pyocyanin production may be responsible for the enhanced virulence of the PAO1 rpoS mutant that was observed in a rat chronic-lung-infection model. In addition, the rpoSmutant displayed an altered twitching-motility phenotype, suggesting that the colonization factors, type IV fimbriae, were affected. Finally, in an alginate-overproducing cystic fibrosis (CF) isolate, FRD1, the rpoS101::aacCI mutation almost completely abolished the production of alginate when the bacterium was grown in a liquid medium. On a solid medium, the FRD1rpoS mutant produced approximately 70% less alginate than did the wild-type strain. Thus, our data indicate that although some of the functions of RpoS in P. aeruginosa physiology are similar to RpoS functions in other gram-negative bacteria, it also has some functions unique to this bacterium.

Role of rhizobia in suppressing the root rot and root knot disease of chili used alone or with Pseudomonas aeruginosa

2019 ◽  
Vol 52 (3) ◽  
Author(s):  
Gulnaz Parveen ◽  
Faizah Urooj ◽  
Hafiza Asma Shafique ◽  
Afshan Rahman ◽  
Syed Ehteshamul Haque
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Root Rot
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