scholarly journals Facultative Anaerobes Shape Multispecies Biofilms Composed of Meat Processing Surface Bacteria and Escherichia coli O157:H7 or Salmonella enterica Serovar Typhimurium

2019 ◽  
Vol 85 (17) ◽  
Author(s):  
Jeyachchandran Visvalingam ◽  
Hui Wang ◽  
Tim C. Ells ◽  
Xianqin Yang
Keyword(s):  
Food Processing ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Single Species ◽  
Meat Processing ◽  
Content Type ◽  
E Coli ◽  
Facultative Anaerobes ◽  
Serovar Typhimurium ◽  
Multispecies Biofilms

ABSTRACT This study investigated the microbial dynamics in multispecies biofilms of Escherichia coli O157:H7 strain 1934 (O157) or Salmonella enterica serovar Typhimurium ATCC 14028 (ST) and 40 strains of meat processing surface bacteria (MPB). Biofilms of O157 or ST with/without MPB were developed on stainless steel coupons at 15°C for up to 6 days. Bacteria in suspensions (inoculum, days 2 and 6) and biofilms (days 2 and 6) were enumerated by plating. The composition of multispecies cultures was determined by 16S rRNA gene sequencing. In suspensions, levels of O157 and ST were ∼2 log higher in single-species than in multispecies cultures on both sampling days. ST was 3 log higher in single-species than in multispecies biofilms. A similar trend, though to a lesser extent, was observed for O157 in biofilms on day 2 but not on day 6. No difference (P > 0.05) in bacterial counts was noted for the two MPB-pathogen cocultures at any time during incubation. Bacterial diversity in multispecies cultures decreased with incubation time, irrespective of the pathogen or culture type. The changes in the relative abundance of MPB were similar for the two MPB-pathogen cocultures, though different interbacterial interactions were noted. Respective fractions of ST and O157 were 2.1% and 0.97% initially and then 0.10% and 0.07% on day 2, and 0.60% and 0.04% on day 6. The relative proportions of facultative anaerobes in both multispecies cultures were greater in both suspensions and biofilms than in the inoculum. Citrobacter, Hafnia, Aeromonas, and Carnobacterium predominated in biofilms but not always in the planktonic cultures. IMPORTANCE Results of this study demonstrate that Salmonella enterica serovar Typhimurium and E. coli O157:H7 can integrate into biofilms when cocultured with bacteria from meat plant processing surfaces. However, the degree of biofilm formation for both pathogens was substantially reduced in the presence of the competing microbiota, with S. Typhimurium more greatly affected than E. coli O157:H7. The expression of extracellular determinants such as curli and cellulose appears to be less important for biofilm formation of the pathogens in multispecies cultures than in monoculture. In contrast to previous reports regarding food processing surface bacteria, data collected here also demonstrate that facultative anaerobes may have a competitive edge over strict aerobes in establishing multispecies biofilms. It would be important to take into account the presence of background bacteria when evaluating the potential persistence of a pathogen in food processing facilities.

scholarly journals The Acyl Homoserine Lactone Receptor, SdiA, of Escherichia coli and Salmonella enterica Serovar Typhimurium Does Not Respond to Indole

2012 ◽  
Vol 78 (15) ◽  
pp. 5424-5431 ◽  
Author(s):  
Anice Sabag-Daigle ◽  
Jitesh A. Soares ◽  
Jenée N. Smith ◽  
Mohamed E. Elmasry ◽  
Brian M. M. Ahmer
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
High Concentrations

ABSTRACTIn this study, we tested the hypothesis that the SdiA proteins ofEscherichia coliandSalmonella entericaserovar Typhimurium respond to indole. While indole was found to have effects on gene expression and biofilm formation, these effects were notsdiAdependent. However, high concentrations of indole did inhibitN-acyl-l-homoserine lactone (AHL) sensing by SdiA. We conclude that SdiA does not respond to indole but indole can inhibit SdiA activity inE. coliandSalmonella.

scholarly journals Effects of Norspermidine and Spermidine on Biofilm Formation by Potentially Pathogenic Escherichia coli and Salmonella enterica Wild-Type Strains

2015 ◽  
Vol 81 (6) ◽  
pp. 2226-2232 ◽  
Author(s):  
Live L. Nesse ◽  
Kristin Berg ◽  
Lene K. Vestby
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Serovar Typhimurium ◽  
And Control ◽  
Type Strains

ABSTRACTPolyamines are present in all living cells. In bacteria, polyamines are involved in a variety of functions, including biofilm formation, thus indicating that polyamines may have potential in the control of unwanted biofilm. In the present study, the effects of the polyamines norspermidine and spermidine on biofilms of 10 potentially pathogenic wild-type strains ofEscherichia coliserotype O103:H2,Salmonella entericasubsp.entericaserovar Typhimurium, andS. entericaserovar Agona were investigated. We found that exogenously supplied norspermidine and spermidine did not mediate disassembly of preformed biofilm of any of theE. coliandS. entericastrains. However, the polyamines did affect biofilm production. Interestingly, the two species reacted differently to the polyamines. Both polyamines reduced the amount of biofilm formed byE. colibut tended to increase biofilm formation byS. enterica. Whether the effects observed were due to the polyamines specifically targeting biofilm formation, being toxic for the cells, or maybe a combination of the two, is not known. However, there were no indications that the effect was mediated through binding to exopolysaccharides, as earlier suggested forE. coli. Our results indicate that norspermidine and spermidine do not have potential as inhibitors ofS. entericabiofilm. Furthermore, we found that the commercial polyamines used contributed to the higher pH of the test medium. Failure to acknowledge and control this important phenomenon may lead to misinterpretation of the results.

scholarly journals Clarithromycin Exerts an Antibiofilm Effect against Salmonella enterica Serovar Typhimurium rdar Biofilm Formation and Transforms the Physiology towards an Apparent Oxygen-Depleted Energy and Carbon Metabolism

2020 ◽  
Vol 88 (11) ◽  
Author(s):  
Munirah Zafar ◽  
Humera Jahan ◽  
Sulman Shafeeq ◽  
Manfred Nimtz ◽  
Lothar Jänsch ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Antibiofilm Activity ◽  
Bacterial Cells ◽  
Content Type ◽  
Regulatory Pathways ◽  
Heat Shock Stress ◽  
Extracellular Matrix Components ◽  
Serovar Typhimurium

ABSTRACT Upon biofilm formation, production of extracellular matrix components and alteration in physiology and metabolism allows bacteria to build up multicellular communities which can facilitate nutrient acquisition during unfavorable conditions and provide protection toward various forms of environmental stresses to individual cells. Thus, bacterial cells within biofilms become tolerant against antimicrobials and the immune system. In the present study, we evaluated the antibiofilm activity of the macrolides clarithromycin and azithromycin. Clarithromycin showed antibiofilm activity against rdar (red, dry, and rough) biofilm formation of the gastrointestinal pathogen Salmonella enterica serovar Typhimurium ATCC 14028 (Nalr) at a 1.56 μM subinhibitory concentration in standing culture and dissolved cell aggregates at 15 μM in a microaerophilic environment, suggesting that the oxygen level affects the activity of the drug. Treatment with clarithromycin significantly decreased transcription and production of the rdar biofilm activator CsgD, with biofilm genes such as csgB and adrA to be concomitantly downregulated. Although fliA and other flagellar regulon genes were upregulated, apparent motility was downregulated. RNA sequencing showed a holistic cell response upon clarithromycin exposure, whereby not only genes involved in the biofilm-related regulatory pathways but also genes that likely contribute to intrinsic antimicrobial resistance, and the heat shock stress response were differentially regulated. Most significantly, clarithromycin exposure shifted the cells toward an apparent oxygen- and energy-depleted status, whereby the metabolism that channels into oxidative phosphorylation was downregulated, and energy gain by degradation of propane 1,2-diol, ethanolamine and l-arginine catabolism, potentially also to prevent cytosolic acidification, was upregulated. This analysis will allow the subsequent identification of novel intrinsic antimicrobial resistance determinants.

scholarly journals Biofilm Formation by Salmonella enterica Serovar Typhimurium and Escherichia coli on Epithelial Cells following Mixed Inoculations

2005 ◽  
Vol 73 (8) ◽  
pp. 5198-5203 ◽  
Author(s):  
Cristina L. C. Esteves ◽  
Bradley D. Jones ◽  
Steven Clegg
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Salmonella Enterica Serovar Typhimurium ◽  
E Coli ◽  
Serovar Typhimurium

ABSTRACT Biofilms were formed by inoculations of Salmonella enterica serovar Typhimurium and Escherichia coli on HEp-2 cells. Inoculations of S. enterica serovar Typhimurium and E. coli resulted in the formation of an extensive biofilm of S. enterica serovar Typhimurium. In experiments where an E. coli biofilm was first formed followed by challenge with S. enterica serovar Typhimurium, there was significant biofilm formation by S. enterica serovar Typhimurium. The results of this study indicate that S. enterica serovar Typhimurium can outgrow E. coli in heterologous infections and displace E. coli when it forms a biofilm on HEp-2 cells.

scholarly journals Inhibition of Salmonella enterica Biofilm Formation Using Small-Molecule Adenosine Mimetics

2014 ◽  
Vol 59 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Jacob A. Koopman ◽  
Joanna M. Marshall ◽  
Aditi Bhatiya ◽  
Tadesse Eguale ◽  
Jesse J. Kwiek ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Mammalian Cells ◽  
Bacterial Species ◽  
Binding Pocket ◽  
Bacterial Biofilm ◽  
Chronic Infections ◽  
Content Type ◽  
Cellular Processes ◽  
Serovar Typhimurium

ABSTRACTBiofilms have been widely implicated in chronic infections and environmental persistence ofSalmonella enterica, facilitating enhanced colonization of surfaces and increasing the ability of the bacteria to be transmitted to new hosts.Salmonella entericaserovar Typhi biofilm formation on gallstones from humans and mice enhances gallbladder colonization and bacterial shedding, whileSalmonella entericaserovar Typhimurium biofilms facilitate long-term persistence in a number of environments important to food, medical, and farming industries.Salmonellaregulates expression of many virulence- and biofilm-related processes using kinase-driven pathways. Kinases play pivotal roles in phosphorylation and energy transfer in cellular processes and possess an ATP-binding pocket required for their functions. Many other cellular proteins also require ATP for their activity. Here we test the hypothesis that pharmacological interference with ATP-requiring enzymes utilizing adenosine mimetic compounds would decrease or inhibit bacterial biofilm formation. Through the screening of a 3,000-member ATP mimetic library, we identified a single compound (compound 7955004) capable of significantly reducing biofilm formation byS. Typhimurium andS. Typhi. The compound was not bactericidal or bacteriostatic towardS. Typhimurium or cytotoxic to mammalian cells. An ATP-Sepharose affinity matrix technique was used to discover potential protein-binding targets of the compound and identified GroEL and DeoD. Compound 7955004 was screened against other known biofilm-forming bacterial species and was found to potently inhibit biofilms ofAcinetobacter baumanniias well. The identification of a lead compound with biofilm-inhibiting capabilities towardSalmonellaprovides a potential new avenue of therapeutic intervention againstSalmonellabiofilm formation, with applicability to biofilms of other bacterial pathogens.

scholarly journals FimA, FimF, and FimH Are Necessary for Assembly of Type 1 Fimbriae on Salmonella enterica Serovar Typhimurium

2012 ◽  
Vol 80 (9) ◽  
pp. 3289-3296 ◽  
Author(s):  
Sarah A. Zeiner ◽  
Brett E. Dwyer ◽  
Steven Clegg
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Food Poisoning ◽  
Enteric Bacteria ◽  
Transcriptional Unit ◽  
Content Type ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Serovar Typhimurium

ABSTRACTSalmonella entericaserovar Typhimurium is a Gram-negative member of the familyEnterobacteriaceaeand is a common cause of bacterial food poisoning in humans. The fimbrial appendages are found on the surface of many enteric bacteria and enable the bacteria to bind to eukaryotic cells.S. Typhimurium type 1 fimbriae are characterized by mannose-sensitive hemagglutination and are assembled via the chaperone/usher pathway.S. Typhimurium type 1 fimbrial proteins are encoded by thefimgene cluster (fimAICDHFZYW), withfimAICDHFexpressed as a single transcriptional unit. The structural components of the fimbriae are FimA (major subunit), FimI, FimH (adhesin), and FimF (adaptor). In order to determine which components are required for fimbrial formation inS. Typhimurium, mutations infimA,fimI,fimH, andfimFwere constructed and examined for their ability to produce surface-assembled fimbriae.S. Typhimurium SL1344ΔfimA, -ΔfimH, and -ΔfimFmutants were unable to assemble fimbriae, indicating that these genes are necessary for fimbrial production inS. Typhimurium. However, SL1344ΔfimIwas able to assemble fimbriae. InEscherichia colitype 1 and Pap fimbriae, at least two adaptors are expressed in addition to the adhesins. However,E. colitype 1 and Pap fimbriae have been reported to be able to assemble fimbriae in the absence of these proteins. These results suggest differences between theS. Typhimurium type 1 fimbrial system and theE. colitype 1 and Pap fimbrial systems.

scholarly journals Multidrug Resistance Regulators MarA, SoxS, Rob, and RamA Repress Flagellar Gene Expression and Motility in Salmonella enterica Serovar Typhimurium

2019 ◽  
Vol 201 (23) ◽  
Author(s):  
Srinivas S. Thota ◽  
Lon M. Chubiz
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Multidrug Resistance ◽  
Related Species ◽  
Salmonella Enterica ◽  
Mrna Translation ◽  
Flagellar Gene ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium

ABSTRACT Production of flagella is costly and subject to global multilayered regulation, which is reflected in the hierarchical control of flagellar production in many bacterial species. For Salmonella enterica serovar Typhimurium and its relatives, global regulation of flagellar production primarily occurs through the control of flhDC transcription and mRNA translation. In this study, the roles of the homologous multidrug resistance regulators MarA, SoxS, Rob, and RamA (constituting the mar-sox-rob regulon in S. Typhimurium) in regulating flagellar gene expression were explored. Each of these regulators was found to inhibit flagellar gene expression, production of flagella, and motility. To different degrees, repression via these transcription factors occurred through direct interactions with the flhDC promoter, particularly for MarA and Rob. Additionally, SoxS repressed flagellar gene expression via a posttranscriptional pathway, reducing flhDC translation. The roles of these transcription factors in reducing motility in the presence of salicylic acid were also elucidated, adding a genetic regulatory element to the response of S. Typhimurium to this well-characterized chemorepellent. Integration of flagellar gene expression into the mar-sox-rob regulon in S. Typhimurium contrasts with findings for closely related species such as Escherichia coli, providing an example of plasticity in the mar-sox-rob regulon throughout the Enterobacteriaceae family. IMPORTANCE The mar-sox-rob regulon is a large and highly conserved stress response network in the Enterobacteriaceae family. Although it is well characterized in E. coli, the extent of this regulon in related species is unclear. Here, the control of costly flagellar gene expression is connected to the mar-sox-rob regulon of S. Typhimurium, contrasting with the E. coli regulon model. These findings demonstrate the flexibility of the mar-sox-rob regulon to accommodate novel regulatory targets, and they provide evidence for its broader regulatory role within this family of diverse bacteria.

scholarly journals The Stringent Response Regulator DksA Is Required for Salmonella enterica Serovar Typhimurium Growth in Minimal Medium, Motility, Biofilm Formation, and Intestinal Colonization

2015 ◽  
Vol 84 (1) ◽  
pp. 375-384 ◽  
Author(s):  
Shalhevet Azriel ◽  
Alina Goren ◽  
Galia Rahav ◽  
Ohad Gal-Mor
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Early Stage ◽  
Response Regulator ◽  
Stringent Response ◽  
Negative Regulator ◽  
Logarithmic Phase ◽  
Content Type ◽  
Serovar Typhimurium

Salmonella entericaserovar Typhimurium is a facultative intracellular human and animal bacterial pathogen posing a major threat to public health worldwide.Salmonellapathogenicity requires complex coordination of multiple physiological and virulence pathways. DksA is a conserved Gram-negative regulator that belongs to a distinct group of transcription factors that bind directly to the RNA polymerase secondary channel, potentiating the effect of the signaling molecule ppGpp during a stringent response. Here, we established that inS.Typhimurium,dksAis induced during the logarithmic phase and DksA is essential for growth in minimal defined medium and plays an important role in motility and biofilm formation. Furthermore, we determined that DksA positively regulates theSalmonellapathogenicity island 1 and motility-chemotaxis genes and is necessary forS.Typhimurium invasion of human epithelial cells and uptake by macrophages. In contrast, DksA was found to be dispensable forS.Typhimurium host cell adhesion. Finally, using the colitis mouse model, we found thatdksAis spatially induced at the midcecum during the early stage of the infection and required for gastrointestinal colonization and systemic infectionin vivo. Taken together, these data indicate that the ancestral stringent response regulator DksA coordinates various physiological and virulenceS.Typhimurium programs and therefore is a key virulence regulator ofSalmonella.

scholarly journals Identification of Salmonella enterica Serovar Typhimurium Genes Regulated during Biofilm Formation on Cholesterol Gallstone Surfaces

2013 ◽  
Vol 81 (10) ◽  
pp. 3770-3780 ◽  
Author(s):  
Geoffrey Gonzalez-Escobedo ◽  
John S. Gunn
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Cholesterol Gallstone ◽  
Structural Genes ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Coated Surfaces ◽  
Biofilm Development

ABSTRACTSalmonellaspp. are able to form biofilms on abiotic and biotic surfaces.In vivostudies in our laboratory have shown thatSalmonellacan form biofilms on the surfaces of cholesterol gallstones in the gallbladders of mice and human carriers. Biofilm formation on gallstones has been demonstrated to be a mechanism of persistence. The purpose of this work was to identify and evaluateSalmonellasp. cholesterol-dependent biofilm factors. Differential gene expression analysis between biofilms on glass or cholesterol-coated surfaces and subsequent quantitative real-time PCR (qRT-PCR) revealed that type 1 fimbria structural genes and a gene encoding a putative outer membrane protein (ycfR) were specifically upregulated inSalmonella entericaserovar Typhimurium biofilms grown on cholesterol-coated surfaces. Spatiotemporal expression ofycfRand FimA verified their regulation during biofilm development on cholesterol-coated surfaces. Surprisingly, confocal and scanning electron microscopy demonstrated that a mutant of type 1 fimbria structural genes (ΔfimAICDHF) and aycfRmutant showed increased biofilm formation on cholesterol-coated surfaces.In vivoexperiments usingNramp1+/+mice harboring gallstones showed that only the ΔycfRmutant formed extensive biofilms on mouse gallstones at 7 and 21 days postinfection; ΔfimAICDHFwas not observed on gallstone surfaces after the 7-day-postinfection time point. These data suggest that inSalmonellaspp., wild-type type 1 fimbriae are important for attachment to and/or persistence on gallstones at later points of chronic infection, whereas YcfR may represent a specific potential natural inhibitor of initial biofilm formation on gallstones.

scholarly journals SadA, a Trimeric Autotransporter from Salmonella enterica Serovar Typhimurium, Can Promote Biofilm Formation and Provides Limited Protection against Infection

2011 ◽  
Vol 79 (11) ◽  
pp. 4342-4352 ◽  
Author(s):  
Dhaarini Raghunathan ◽  
Timothy J. Wells ◽  
Faye C. Morris ◽  
Robert K. Shaw ◽  
Saeeda Bobat ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Protective Antigen ◽  
Outer Membrane Proteins ◽  
Cell Aggregation ◽  
Sub Saharan Africa ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTSalmonella entericais a major cause of morbidity worldwide and mortality in children and immunocompromised individuals in sub-Saharan Africa. Outer membrane proteins ofSalmonellaare of significance because they are at the interface between the pathogen and the host, they can contribute to adherence, colonization, and virulence, and they are frequently targets of antibody-mediated immunity. In this study, the properties of SadA, a purported trimeric autotransporter adhesin ofSalmonella entericaserovar Typhimurium, were examined. We demonstrated that SadA is exposed on theSalmonellacell surfacein vitroandin vivoduring infection of mice. Expression of SadA resulted in cell aggregation, biofilm formation, and increased adhesion to human intestinal Caco-2 epithelial cells. Immunization of mice with folded, full-length, purified SadA elicited an IgG response which provided limited protection against bacterial challenge. When anti-SadA IgG titers were enhanced by administering alum-precipitated protein, a modest additional protection was afforded. Therefore, despite SadA having pleiotropic functions, it is not a dominant, protective antigen for antibody-mediated protection againstSalmonella.

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