scholarly journals An Overview of Virulence-Associated Factors of Gram-Negative Fish Pathogenic Bacteria

10.5772/29837 ◽  
2012 ◽  
Author(s):  
Jessica Mndez ◽  
Pilar Reimundo ◽  
David Prez-Pascual ◽  
Roberto Navais ◽  
Esther Gmez ◽  
...  
Keyword(s):  
Associated Factors ◽  
Pathogenic Bacteria ◽  
Gram Negative

An outlook for food sterilization technology: targeting the outer membrane of foodborne gram-negative pathogenic bacteria

2021 ◽  
Vol 42 ◽  
pp. 15-22
Author(s):  
Zhaohuan Zhang ◽  
Zhenhua Huang ◽  
Jinrong Tong ◽  
Qian Wu ◽  
Yingjie Pan ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Pathogenic Bacteria ◽  
Gram Negative ◽  
Food Sterilization

Biosynthesis of Silver Nanoparticles by Punica Granatum Peel Extract and their Biological Activity on different Pathogenic Bacteria

2021 ◽  
Vol 19 (9) ◽  
pp. 38-45
Author(s):  
Hussein H. Al-Turnachy ◽  
Fadhilk. alibraheemi ◽  
Ahmed Abd Alreda Madhloom ◽  
Zahraa Yosif Motaweq ◽  
Nibras Yahya Abdulla
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Biological Activity ◽  
Pathogenic Bacteria ◽  
Punica Granatum ◽  
Gram Positive ◽  
Gram Negative ◽  
Inhibition Zones ◽  
Peel Extract

The present study was included the assessment of the antimicrobial activity of AgNPs synthesized by Punica granatum peel extract against pathogenic bacteria by testing warm aqueous P. granatum peel extract and silver nanoparticles. Punica granatum indicated potency for AgNP extracellular nanobiosynthesis after addition of silver nitrate (AgNO3) 4mM to the extract supernatant, in both concentrations (100mg and 50mg). The biogenic AgNPs showed potency to inhibit both gram-negative and gram-positive bacterial growth. Zons of inhibition in (mm) was lesser in gram-positive than gram-negative bacteria. The resulted phytogenic AgNPs gave higher biological activity than warm aqueous Punica granatum peel extract. The inhibition zone of the phytogenic AgNPs on E. coli reached 17.53, 22.35, and 26.06 mm at (0.1, 0.5, and 1) mg/ml respectively. While inhibition zones of Punica warm aqueous extract reached 5.33, 10.63, and 16.08 mm at the same concentrations. phytogenic AgNPs gave smaller inhibition zones in gram-positive than gram- negative. Cytotoxic activity of the phytogenic AgNPs was assayed in vitro agaist human blood erythrocytes (RBCs), spectroscopic results showed absorbance at 540 nm hemolysis was observed. In general, AgNPs showed least RBCs hemolysis percentage, at 1 mg/ml concentration, hemolysis percentage was (4.50%). This study, concluded that the Punica granatum peel extract has the power of synthses of AgNPs characterized by broad spectrum antimicrobial activity with cyto-toxicity proportional to AgNPs concentration.

The penetration of Human Defensin 5 (HD5) through bacterial outer membrane: Simulation studies

2021 ◽  
Author(s):  
Tadsanee Awang ◽  
Prapasiri Pongprayoon
Keyword(s):  
Pathogenic Bacteria ◽  
Lipid A ◽  
Dominant Role ◽  
Membrane Surface ◽  
Innate Immune ◽  
Hydrophobic Core ◽  
Gram Negative ◽  
Head Groups ◽  
Bacterial Outer Membrane ◽  
Human Defensin 5

Abstract Human α-defensin 5 (HD5) is one of cationic antimicrobial peptides which plays a crucial role in an innate immune system in human body. HD5 shows the killing activity against a broad spectrum of pathogenic bacteria by making a pore in a bacterial membrane and penetrating into a cytosol. Nonetheless, its pore-forming mechanisms remain unclear. Thus, in this work, the constant-velocity steered molecular dynamics (SMD) simulation was used to simulate the permeation of a dimeric HD5 into a gram-negative LPS membrane model. Arginine-rich HD5 is found to strongly interact with a LPS surface. Upon arrival, arginines on HD5 interact with lipid A head groups and then drag these charged moieties down into a hydrophobic core resulting in the formation of water-filled pore. Although all arginines are found to interact with a membrane, R13 and R32 appear to play a dominant role in the HD5 adsorption on a gram-negative membrane. Furthermore, one chain of a dimeric HD5 is required for HD5 adhesion. The interactions of arginine-Lipid A head groups play a major role in adhering a cationic HD5 on a membrane surface and retarding a HD5 passage in the meantime.

Effectiveness of Trisodium Phosphate, Acidified Sodium Chlorite, Citric Acid, and Peroxyacids against Pathogenic Bacteria on Poultry during Refrigerated Storage

2007 ◽  
Vol 70 (9) ◽  
pp. 2063-2071 ◽  
Author(s):  
ELENA del RÍO ◽  
REBECA MURIENTE ◽  
MIGUEL PRIETO ◽  
CARLOS ALONSO-CALLEJA ◽  
ROSA CAPITA
Keyword(s):  
Citric Acid ◽  
Salmonella Enteritidis ◽  
Pathogenic Bacteria ◽  
Trisodium Phosphate ◽  
Sodium Chlorite ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Microbial Group ◽  
And Control

The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 ± 1°C. All chemical solutions reduced microbial populations (P < 0.001) as compared with the control (untreated) samples. Similar bacterial loads (P > 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of storage, the pH of legs treated with TSP remained higher and that of legs treated with CA remained lower than normal.

scholarly journals Study of antimicrobial susceptibility of clinically significant microorganisms isolated from selected areas of Dhaka, Bangladesh

2013 ◽  
Vol 12 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Subarna Dutta ◽  
Md Rokibul Hassan ◽  
Farjana Rahman ◽  
Md Shariful Alam Jilani ◽  
Rashed Noor
Keyword(s):  
Pathogenic Bacteria ◽  
Medical Science ◽  
Vaginal Swab ◽  
Antibiotic Prescribing ◽  
Gram Negative ◽  
Methicillin Resistant ◽  
Clinical Specimens ◽  
Baseline Information ◽  
Clinically Significant ◽  
Susceptibility Tests

Objective: Pathogenic resistance against antibiotics is substantially mounting in the developing countries including Bangladesh. Present study thus attempted to obtain the baseline information on such resistance among the community people coming to the local dispensaries around the city of Dhaka for treatment. Materials and Methods: A total of 2,700 clinical specimens were examined for the presence of Gram positive and Gram negative pathogens. Antibiotic susceptibility tests of the isolates were carried out. Extended spectrum b- lactamase (ESBL) activity, and the presence of methicillin resistant Staphylococcus aureus (MRSA) and S. epidermidis (MRSE) were also detected. Results: Escherichia coli were most prevalent (45.5%) among 1044 pathogenic bacteria isolated from 2,700 samples. E. coli predominated urine, pus, wound swab, blood, high vaginal swab (HVS) and sputum specimens, and exhibited the highest frequency of ESBL activity (35%). Prevalence of Klebsiella spp. and S. aureus among the clinical specimens were 11.5% and 9.86%, respectively. Most of the Gram negative bacilli were found resistant against ciprofloxacin (5 mg), tetracycline (30 mg) and cotrimoxazole (25 mg). Majority of Pseudomonas spp. were found resistant against most of the commonly used antibiotics. Interestingly, around half of the S. aureus isolates were observed to be methicillin resistant, but not vancomycin resistant. Conclusion: Overall, such a revelation of increased antibiotic resistance demands for restrictive and appropriate antibiotic usage in accordance with the updated antibiotic prescribing policy in Bangladesh. DOI: http://dx.doi.org/10.3329/bjms.v12i1.13351 Bangladesh Journal of Medical Science Vol. 12 No. 01 January’13 pp.34-42

scholarly journals Autotransporter secretion exploits the bacterial actin-homologue

2018 ◽  
Author(s):  
Mahmoud M. Ashawesh ◽  
Robert Markus ◽  
Christopher N. Penfold ◽  
Kim R. Hardie
Keyword(s):  
Bacterial Infection ◽  
Virulence Factors ◽  
Pathogenic Bacteria ◽  
Super Resolution ◽  
Resistance Mechanisms ◽  
Dynamic Interaction ◽  
Bacterial Toxins ◽  
Gram Negative ◽  
Bacterial Cytoskeleton ◽  
Development Of Resistance

AbstractBacterial infection of humans, animals and plants relies heavily on secreted proteases that degrade host defences or activate bacterial toxins. The largest family of proteins secreted by Gram-negative pathogenic bacteria, the Autotransporters (ATs), includes key proteolytic virulence factors. There remains uncertainty about the mechanistic steps of the pathway ATs share to exit bacteria, and how it is energetically driven. This study set out to shed light on the AT secretion pathway with the ultimate aim of uncovering novel antimicrobial targets that would be unlikely to trigger the development of resistance mechanisms in bacteria. To do this, two AT virulence factors with distinct proteolytic functions, EspC (secreted from EnteropathogenicEscherichia coli) and AaaA (tethered to the extracellular surface ofPseudomonas aeruginosa) were chosen. EspC and AaaA were fluorescently labelled using two separate methods to establish the localization patterns of ATs as they are secreted from a bacterial cell. Super resolution microscopy revealed that localization of ATs occurs via a helical route along the bacterial cytoskeleton. In addition to requiring the conserved C-terminal β-barrel translocator domain of the AT, we present the first evidence that secretion is dependent on a dynamic interaction with a structure reliant upon the actin homologue MreB and the Sec translocon. These findings provide a step forward in the mechanistic understanding of the secretion of this widely distributed family of proteins that have pivotal roles in bacterial pathogenesis and conserved structural properties that could serve as novel broad-range antimicrobial targets.SignificanceSecreted bacterial proteases facilitate the infection of human, animal and plant hosts by degrading host defences or activating bacterial toxins. The autotransporter family is the largest family of proteins secreted from Gram-negative bacteria, and includes proteolytic virulence factors crucial to bacterial infection. Precisely how autotransporters migrate from the inside to the outside of the cell, and how this movement is energetically driven is a mystery. We demonstrate a spiral pathway of autotransporter secretion, presenting evidence that it involves a dynamic interaction with the actin homologue MreB that comprises the bacterial cytoskeleton. Our findings open the way to unravelling the mechanism of autotransporter secretion and offer the possibility to identify novel antimicrobial targets unlikely to trigger the development of antimicrobial resistance.

scholarly journals Antimicrobial Activity of Gardenia jasminoides Callus and Crude Leaf Extracts for some Organic Solvents against some Pathogenic Bacteria and Yeasts

2014 ◽  
Vol 8 (3) ◽  
pp. 40-45
Author(s):  
Zina Hashem Shehab ◽  
Huda Suhail Abid ◽  
Sumaya Fadhil Hamad ◽  
Sara Haitham
Keyword(s):  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Pathogenic Bacteria ◽  
Saccharomyces Boulardii ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Gardenia Jasminoides

The study was conducted to evaluate the inhibitory activity of methanol extract of Gardenia jasminoides leaves compared with leaf crude extracts for some organic solvents namely Methanol, Ethanol, Petroleum ether, Asetone and Chloroform on growth of some pathogenic bacteria and yeast, which included four gram positive isolates Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes and Bacillus cereus and gram negative isolates Escherichia coli, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa and some yeasts Candida albicans and Saccharomyces boulardii, by using well diffusion method. The inhibitory activity of extracts in the tested bacterial strains and yeasts was varied according to the type of extracting solvents and are tested microorganisms. The methanol callus extract which grown on Murashige and Skoog (MS) media by using (Naphthalen acitic acid) NAA and (Benzyle adenine) BA as growth regulator highly effective as compared to the other extracts as for inhibition of three gram positive bacteria and three gram negative bacteria,which include Staphylococcus aureus and, Proteus vulgaris, followed by acetone and ethanolic extracts which include two gram positive bacteria and two gram negative bacteria. All extracts had highly effect in growth of Candida albicans while all crude extracts didn’t show any sensitivity against Saccharomyces boulardii, and when we’d done (High Performance Liquid Chromatography) HPLC test for detection of some active compound we found Quinic acid, Iridiods glycosides and Crocin which its rate in fresh callus was higher than fresh leaves.

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