scholarly journals Immediate Reduction of Salmonella enterica Serotype Typhimurium Viability via Membrane Destabilization following Exposure to Multiple-Hurdle Treatments with Heated, Acidified Organic Acid Salt Solutions

2011 ◽  
Vol 77 (11) ◽  
pp. 3765-3772 ◽  
Author(s):  
S. R. Milillo ◽  
E. Martin ◽  
A. Muthaiyan ◽  
S. C. Ricke
Keyword(s):  
Cell Membrane ◽  
Organic Acid ◽  
Salmonella Enterica ◽  
Sodium Acetate ◽  
Specific Response ◽  
Ion Leakage ◽  
Acid Salt ◽  
Salt Solutions ◽  
Sodium Propionate ◽  
Content Type

ABSTRACTThe antimicrobial activity of organic acids in combination with nonchemical treatments was evaluated for inactivation ofSalmonella entericaserotype Typhimurium within 1 min. It was observed that the effectiveness of the multiple-hurdle treatments was temperature (P≤ 0.05) and pH (P≤ 0.05) dependent and corresponded to the degree of organic acid lipophilicity (sodium acetate being least effective and sodium propionate being the most effective). This led to the hypothesis that the loss in viability was due at least in part to cell membrane disruption. Evaluation of osmotic response, potassium ion leakage, and transmission electron micrographs confirmed treatment effects on the cell membrane. Interestingly, all treatments, even those with no effect on viability, such as with sodium acetate, resulted in measurable cellular stress. Microarray experiments explored the specific response ofS. Typhimurium to sodium acetate and sodium propionate, the most similar of the tested treatments in terms of pKaand ionic strength, and found little difference in the changes in gene expression following exposure to either, despite their very different effects on viability. Taken together, the results reported support our hypothesis that treatment with heated, acidified, organic acid salt solutions for 1 min causes loss ofS. Typhimurium viability at least in part by membrane damage and that the degree of effectiveness can be correlated with lipophilicity of the organic acid. Overall, the data presented here indicate that a combined thermal, acidified sodium propionate treatment can provide an effective antimicrobial treatment againstSalmonella.

Helix-random chain transitions of polyamino acids in organic acid-salt solutions

Biopolymers ◽  
1966 ◽  
Vol 4 (6) ◽  
pp. 637-651 ◽  
Author(s):  
James S. Franzen ◽  
Caroline Bobik ◽  
John B. Harry
Keyword(s):  
Organic Acid ◽  
Acid Salt ◽  
Salt Solutions

Effects of Organic Acid Salt Solutions on Sensory and Other Quality Characteristics of Frankfurters

2005 ◽  
Vol 70 (2) ◽  
pp. S123-S127 ◽  
Author(s):  
Zheng Lu ◽  
Joseph G. Sebranek ◽  
J.S. Dickson ◽  
A.F. Mendonca ◽  
T.B. Bailey
Keyword(s):  
Organic Acid ◽  
Quality Characteristics ◽  
Acid Salt ◽  
Salt Solutions

scholarly journals Efficiency of Conditionally Attenuated Salmonella enterica Serovar Typhimurium in Bacterium-Mediated Tumor Therapy

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Michael Frahm ◽  
Sebastian Felgner ◽  
Dino Kocijancic ◽  
Manfred Rohde ◽  
Michael Hensel ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Tumor Targeting ◽  
Antitumor Effect ◽  
Treatment Options ◽  
Tumor Therapy ◽  
Therapeutic Benefit ◽  
Industrialized Countries ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Therapeutic Molecules

ABSTRACTIncreasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria likeSalmonella entericaserovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenicS. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (ΔrfaL, ΔrfaG, ΔrfaH, ΔrfaD, ΔrfaP, and ΔmsbBmutants) ofSalmonellawere investigated for efficiency in tumor therapy. Of such variants, the ΔrfaDand ΔrfaGdeep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into thearaBADlocus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium.IMPORTANCECancer has become the second most frequent cause of death in industrialized countries. This and the drawbacks of routine therapies generate an urgent need for novel treatment options. Applying appropriately modifiedS. Typhimurium for therapy represents the major challenge of bacterium-mediated tumor therapy. In the present study, we demonstrated thatSalmonellabacteria conditionally modified in their LPS phenotype exhibit a safe tumor-targeting phenotype. Moreover, they could represent a suitable vehicle to shuttle therapeutic compounds directly into cancerous tissue without harming the host.

scholarly journals Occurrence of Antimicrobial-Resistant Escherichia coli and Salmonella enterica in the Beef Cattle Production and Processing Continuum

2014 ◽  
Vol 81 (2) ◽  
pp. 713-725 ◽  
Author(s):  
John W. Schmidt ◽  
Getahun E. Agga ◽  
Joseph M. Bosilevac ◽  
Dayna M. Brichta-Harhay ◽  
Steven D. Shackelford ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Generation Cephalosporin ◽  
Resistant Bacteria ◽  
Processing Plant ◽  
Cattle Production ◽  
Content Type ◽  
E Coli ◽  
Beef Processing ◽  
Tract Infections

ABSTRACTSpecific concerns have been raised that third-generation cephalosporin-resistant (3GCr)Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COTr)E. coli, 3GCrSalmonella enterica, and nalidixic acid-resistant (NALr)S. entericamay be present in cattle production environments, persist through beef processing, and contaminate final products. The prevalences and concentrations of these organisms were determined in feces and hides (at feedlot and processing plant), pre-evisceration carcasses, and final carcasses from three lots of fed cattle (n= 184). The prevalences and concentrations were further determined for strip loins from 103 of the carcasses. 3GCrSalmonellawas detected on 7.6% of hides during processing and was not detected on the final carcasses or strip loins. NALrS. entericawas detected on only one hide. 3GCrE. coliand COTrE. coliwere detected on 100.0% of hides during processing. Concentrations of 3GCrE. coliand COTrE. colion hides were correlated with pre-evisceration carcass contamination. 3GCrE. coliand COTrE. coliwere each detected on only 0.5% of final carcasses and were not detected on strip loins. Five hundred and 42 isolates were screened for extraintestinal pathogenicE. coli(ExPEC) virulence-associated markers. Only two COTrE. coliisolates from hides were ExPEC, indicating that fed cattle products are not a significant source of ExPEC causing human urinary tract infections. The very low prevalences of these organisms on final carcasses and their absence on strip loins demonstrate that current sanitary dressing procedures and processing interventions are effective against antimicrobial-resistant bacteria.

scholarly journals ArmA Methyltransferase in a Monophasic Salmonella enterica Isolate from Food

2011 ◽  
Vol 55 (11) ◽  
pp. 5262-5266 ◽  
Author(s):  
Sophie A. Granier ◽  
Laura Hidalgo ◽  
Alvaro San Millan ◽  
Jose Antonio Escudero ◽  
Belen Gutierrez ◽  
...  
Keyword(s):  
16S Rrna ◽  
Salmonella Enterica ◽  
Multidrug Resistant ◽  
Broad Host Range ◽  
En Bloc ◽  
Content Type ◽  
Route Of Transmission ◽  
Amoxicillin Clavulanate ◽  
High Level ◽  
Level Resistance

ABSTRACTThe 16S rRNA methyltransferase ArmA is a worldwide emerging determinant that confers high-level resistance to most clinically relevant aminoglycosides. We report here the identification and characterization of a multidrug-resistantSalmonella entericasubspecies I.4,12:i:− isolate recovered from chicken meat sampled in a supermarket on February 2009 in La Reunion, a French island in the Indian Ocean. Susceptibility testing showed an unusually high-level resistance to gentamicin, as well as to ampicillin, expanded-spectrum cephalosporins and amoxicillin-clavulanate. Molecular analysis of the 16S rRNA methyltransferases revealed presence of thearmAgene, together withblaTEM-1,blaCMY-2, andblaCTX-M-3. All of these genes could be transferreden blocthrough conjugation intoEscherichia coliat a frequency of 10−5CFU/donor. Replicon typing and S1 pulsed-field gel electrophoresis revealed that thearmAgene was borne on an ∼150-kb broad-host-range IncP plasmid, pB1010. To elucidate howarmAhad integrated in pB1010, a PCR mapping strategy was developed for Tn1548, the genetic platform forarmA.The gene was embedded in a Tn1548-like structure, albeit with a deletion of the macrolide resistance genes, and an IS26was inserted within themelgene. To our knowledge, this is the first report of ArmA methyltransferase in food, showing a novel route of transmission for this resistance determinant. Further surveillance in food-borne bacteria will be crucial to determine the role of food in the spread of 16S rRNA methyltransferase genes worldwide.

scholarly journals OXA-48 Carbapenemase-Producing Salmonella enterica Serovar Kentucky Isolate of Sequence Type 198 in a Patient Transferred from Libya to Switzerland

2014 ◽  
Vol 58 (4) ◽  
pp. 2446-2449 ◽  
Author(s):  
Salome N. Seiffert ◽  
Vincent Perreten ◽  
Sönke Johannes ◽  
Sara Droz ◽  
Thomas Bodmer ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Salmonella Enterica ◽  
Sequence Type ◽  
Content Type ◽  
Screening Strategies

ABSTRACTHere, we report a case of OXA-48-producingSalmonella entericaserovar Kentucky of sequence type 198 (ST198) from perianal screening cultures of a patient transferred from Libya to Switzerland. TheblaOXA-48gene was carried by Tn1999.2and located on an ∼60-kb IncL/M plasmid. ThisSalmonellastrain also possessed theblaVEB-8,aac(6)-Ib,tet(A),sul1, andmphAresistance genes and substitutions in GyrA (Ser83Phe and Asp87Asn) and ParC (Ser80Ile). This finding emphasizes that prompt screening strategies are essential to prevent the dissemination of carbapenemase producers imported from countries where they are endemic.

scholarly journals A Salmonella Virulence Factor Activates the NOD1/NOD2 Signaling Pathway

mBio ◽  
2011 ◽  
Vol 2 (6) ◽  
Author(s):  
A. Marijke Keestra ◽  
Maria G. Winter ◽  
Daisy Klein-Douwel ◽  
Mariana N. Xavier ◽  
Sebastian E. Winter ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Intestinal Inflammation ◽  
Inflammatory Responses ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Content Type ◽  
Type Iii

ABSTRACTThe invasion-associated type III secretion system (T3SS-1) ofSalmonella entericaserotype Typhimurium (S. Typhimurium) activates the transcription factor NF-κB in tissue culture cells and induces inflammatory responses in animal models through unknown mechanisms. Here we show that bacterial delivery or ectopic expression of SipA, a T3SS-1-translocated protein, led to the activation of the NOD1/NOD2 signaling pathway and consequent RIP2-mediated induction of NF-κB-dependent inflammatory responses. SipA-mediated activation of NOD1/NOD2 signaling was independent of bacterial invasionin vitrobut required an intact T3SS-1. In the mouse colitis model, SipA triggered mucosal inflammation in wild-type mice but not in NOD1/NOD2-deficient mice. These findings implicate SipA-driven activation of the NOD1/NOD2 signaling pathway as a mechanism by which the T3SS-1 induces inflammatory responsesin vitroandin vivo.IMPORTANCESalmonella entericaserotype Typhimurium (S. Typhimurium) deploys a type III secretion system (T3SS-1) to induce intestinal inflammation and benefits from the ensuing host response, which enhances growth of the pathogen in the intestinal lumen. However, the mechanisms by which the T3SS-1 triggers inflammatory responses have not been resolved. Here we show that the T3SS-1 effector protein SipA induces NF-κB activation and intestinal inflammation by activating the NOD1/NOD2 signaling pathway. These data suggest that the T3SS-1 escalates innate responses through a SipA-mediated activation of pattern recognition receptors in the host cell cytosol.

scholarly journals Naturally Occurring Motility-Defective Mutants of Salmonella enterica Serovar Enteritidis Isolated Preferentially from Nonhuman Rather than Human Sources

2011 ◽  
Vol 77 (21) ◽  
pp. 7740-7748 ◽  
Author(s):  
Lucía Yim ◽  
Laura Betancor ◽  
Arací Martínez ◽  
Clare Bryant ◽  
Duncan Maskell ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Intestinal Epithelial ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Transcriptional Responses ◽  
Content Type ◽  
Field Isolates ◽  
Specific Pcr ◽  
Human Intestinal Epithelial Cells ◽  
Natural Isolates ◽  
Cell Invasiveness

ABSTRACTSalmonellosis represents a worldwide health problem because it is one of the major causes of food-borne disease. Although motility is postulated as an importantSalmonellavirulence attribute, there is little information about variation in motility in natural isolates. Here we report the identification of a point mutation (T551 → G) inmotA, a gene essential for flagellar rotation, in severalSalmonella entericaserovar Enteritidis field isolates. This mutation results in bacteria that can biosynthesize structurally normal but paralyzed flagella and are impaired in their capacity to invade human intestinal epithelial cells. Introduction of a wild-type copy ofmotAinto one of these isolates restored both motility and cell invasiveness. ThemotAmutant triggered higher proinflammatory transcriptional responses than an aflagellate isolate in differentiated Caco-2 cells, suggesting that the paralyzed flagella are able to signal through pattern recognition receptors. A specific PCR was designed to screen for the T551 → G mutation in a collection of 266S. Enteritidis field isolates from a nationwide epidemic, comprising 194 from humans and 72 from other sources. We found that 72 of the 266 (27%) isolates were nonmotile, including 24.7% (48/194) of human and 33.3% (24/72) of food isolates. Among nonmotile isolates, 15 carried the T551 → G mutation and, significantly, 13 were recovered from food, including 7 from eggs, but only 2 were from human sources. These results suggest that the presence of paralyzed flagella may impair the ability ofS. Enteritidis to cause disease in the human host but does not prevent its ability to colonize chickens and infect eggs.

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