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 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 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.

Detection of Escherichia coli O157, Salmonella enterica Serovar Typhimurium, and Staphylococcal Enterotoxin B in a Single Sample Using Enzymatic Bio-Nanotransduction

2007 ◽  
Vol 70 (4) ◽  
pp. 841-850 ◽  
Author(s):  
JOSH R. BRANEN ◽  
MARTHA J. HASS ◽  
ERIN R. DOUTHIT ◽  
WUSI C. MAKI ◽  
A. LARRY BRANEN
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Staphylococcal Enterotoxin B ◽  
Escherichia Coli O157 ◽  
Dna Templates ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Biological Recognition ◽  
Enterotoxin B

Enzymatic bio-nanotransduction is a biological detection scheme based on the production of nucleic acid nano-signals (RNA) in response to specific biological recognition events. In this study, we applied an enzymatic bio-nanotransduction system to the detection of important food-related pathogens and a toxin. Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and staphylococcal enterotoxin B (SEB) were chosen because of the implications of these targets to food safety. Primary antibodies to each of the targets were used to functionalize magnetic beads and produce biological recognition elements (antibodies) conjugated to nano-signal–producing DNA templates. Immunomagnetic capture that was followed by in vitro transcription of DNA templates bound to target molecules produced RNA nano-signals specific for every target in the sample. Discrimination of RNA nano-signals with a standard enzyme-linked oligonucleotide fluorescence assay provided a correlation between nano-signal profiles and target concentrations. The estimated limit of detection was 2.4 × 103 CFU/ml for E. coli O157:H7, 1.9 × 104 CFU/ml for S. enterica serovar Typhimurium, and 0.11 ng/ml for SEB with multianalyte detection in buffer. Low levels of one target were also detected in the presence of interference from high levels of the other targets. Finally, targets were detected in milk, and detection was improved for E. coli O157 by heat treatment of the milk.

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 Salmonella enterica Serovar Typhimurium and Escherichia coli Survival in Estuarine Bank Sediments

2018 ◽  
Vol 15 (11) ◽  
pp. 2597 ◽  
Author(s):  
Mahbubul Siddiqee ◽  
Rebekah Henry ◽  
Rebecca Coulthard ◽  
Christelle Schang ◽  
Richard Williamson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Growth Patterns ◽  
Estuarine Sediments ◽  
Human Pathogens ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
E Coli ◽  
Serovar Typhimurium

Estuarine bank sediments have the potential to support the survival and growth of fecal indicator organisms, including Escherichia coli. However, survival of fecal pathogens in estuarine sediments is not well researched and therefore remains a significant knowledge gap regarding public health risks in estuaries. In this study, simultaneous survival of Escherichia coli and a fecal pathogen, Salmonella enterica serovar Typhimurium, was studied for 21 days in estuarine bank sediment microcosms. Observed growth patterns for both organisms were comparable under four simulated scenarios; for continuous-desiccation, extended-desiccation, periodic-inundation, and continuous-inundation systems, logarithmic decay coefficients were 1.54/day, 1.51/day, 0.14/day, and 0.20/day, respectively, for E. coli, and 1.72/day, 1.64/day, 0.21/day, and 0.24/day for S. Typhimurium. Re-wetting of continuous-desiccated systems resulted in potential re-growth, suggesting survival under moisture-limited conditions. Key findings from this study include: (i) Bank sediments can potentially support human pathogens (S. Typhimurium), (ii) inundation levels influence the survival of fecal bacteria in estuarine bank sediments, and (iii) comparable survival rates of S. Typhimurium and E. coli implies the latter could be a reliable fecal indicator in urban estuaries. The results from this study will help select suitable monitoring and management strategies for safer recreational activities in urban estuaries.

scholarly journals Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Exposed to Microcin-Producing Escherichia coli

2001 ◽  
Vol 67 (8) ◽  
pp. 3763-3766 ◽  
Author(s):  
Steve A. Carlson ◽  
Timothy S. Frana ◽  
Ronald W. Griffith
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Defense Mechanism ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Multidrug Resistant ◽  
E Coli ◽  
Resistant Phenotype ◽  
Serovar Typhimurium

ABSTRACT Microcin 24 is an antimicrobial peptide secreted by uropathogenicEscherichia coli. Secretion of microcin 24 provides an antibacterial defense mechanism for E. coli. In a plasmid-based system using transformed Salmonella enterica, we found that resistance to microcin 24 could be seen in concert with a multiple-antibiotic resistance phenotype. This multidrug-resistant phenotype appeared when Salmonella was exposed to an E. coli strain expressing microcin 24. Therefore, it appears that multidrug-resistant Salmonellacan arise as a result of an insult from other pathogenic bacteria.

scholarly journals Mixed Biofilm Formation by Shiga Toxin–Producing Escherichia coli and Salmonella enterica Serovar Typhimurium Enhanced Bacterial Resistance to Sanitization due to Extracellular Polymeric Substances†

2013 ◽  
Vol 76 (9) ◽  
pp. 1513-1522 ◽  
Author(s):  
RONG WANG ◽  
NORASAK KALCHAYANAND ◽  
JOHN W. SCHMIDT ◽  
DAYNA M. HARHAY
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Bacterial Resistance ◽  
Salmonella Enterica Serovar Typhimurium ◽  
E Coli ◽  
Serovar Typhimurium

Shiga toxin–producing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium are important foodborne pathogens capable of forming single-species biofilms or coexisting in multispecies biofilm communities. Bacterial biofilm cells are usually more resistant to sanitization than their planktonic counterparts, so these foodborne pathogens in biofilms pose a serious food safety concern. We investigated how the coexistence of E. coli O157:H7 and Salmonella Typhimurium strains would affect bacterial planktonic growth competition and mixed biofilm composition. Furthermore, we also investigated how mixed biofilm formation would affect bacterial resistance to common sanitizers. Salmonella Typhimurium strains were able to outcompete E. coli strains in the planktonic growth phase; however, mixed biofilm development was highly dependent upon companion strain properties in terms of the expression of bacterial extracellular polymeric substances (EPS), including curli fimbriae and exopolysaccharide cellulose. The EPS-producing strains with higher biofilm-forming abilities were able to establish themselves in mixed biofilms more efficiently. In comparison to single-strain biofilms, Salmonella or E. coli strains with negative EPS expression obtained significantly enhanced resistance to sanitization by forming mixed biofilms with an EPS-producing companion strain of the other species. These observations indicate that the bacterial EPS components not only enhance the sanitizer resistance of the EPS-producing strains but also render protections to their companion strains, regardless of species, in mixed biofilms. Our study highlights the potential risk of cross-contamination by multispecies biofilms in food safety and the need for increased attention to proper sanitization practices in food processing facilities.

scholarly journals Genome Sequence of Bacteriophage GG32, Which Can Infect both Salmonella enterica Serovar Typhimurium and Escherichia coli O157:H7

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Su-Jin Chae ◽  
Taesoo Kwon ◽  
Sunjin Lee ◽  
Yeon Ho Kang ◽  
Gyung Tae Chung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Control Agent ◽  
Republic Of Korea ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Serovar Typhimurium ◽  
The Republic

We report here a new virulent Salmonella enterica serovar Typhimurium ( S . Typhimurium) bacteriophage, GG32, which was isolated from the Guem River in the Republic of Korea. The strain can infect both S . Typhimurium and Escherichia coli ( E. coli ) O157:H7 and may be a good candidate for a bio-control agent.

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.

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