scholarly journals Systematic analyses of factors required for adhesion of Salmonella enterica serovar Typhimurium to corn salad (Valerianella locusta)

2019 ◽  
Author(s):  
Laura Elpers ◽  
Juliane Kretzschmar ◽  
Sean-Paul Nuccio ◽  
Andreas J. Bäumler ◽  
Michael Hensel
Keyword(s):  
Salmonella Enterica ◽  
Foodborne Pathogen ◽  
Secretion System ◽  
Animal Origin ◽  
Synthetic Approach ◽  
Surface Binding ◽  
Animal Products ◽  
Food Of Animal Origin ◽  
Serovar Typhimurium

AbstractSalmonella enterica is a foodborne pathogen leading to gastroenteritis and is commonly acquired by consumption of contaminated food of animal origin. However, numbers of outbreaks linked to the consumption of fresh or minimally processed food of non-animal origin are increasing. New infection routes of S. enterica by vegetables, fruits, nuts and herbs have to be considered. This leads to special interest in S. enterica interactions with leafy products, e.g. salads, that are consumed unprocessed. The attachment of S. enterica to salad is a crucial step in contamination, but little is known about the bacterial factors required and mechanisms of adhesion. S. enterica possesses a complex set of adhesive structures whose functions are only partly understood. Potentially, S. enterica may deploy multiple adhesive strategies for adhering to various salad species, and other vegetables. Here, we systematically analyzed the contribution of the complete adhesiome, of LPS, and of flagella-mediated motility of S. enterica serovar Typhimurium (STM) in adhesion to corn salad. We deployed a reductionist, synthetic approach to identify factors involved in the surface binding of STM to leaves of corn salad with particular regard to the expression of all known adhesive structures using the Tet-on system. This work reveals the contribution of Saf fimbriae, type 1 secretion system-secreted BapA, an intact LPS, and flagella-mediated motility of STM in adhesion to corn salad leaves.ImportanceHuman gastrointestinal pathogens are often transmitted by animal products, but recent outbreaks show increasing importance of vegetables as source of infection by pathogenic E. coli or Salmonella enterica. The mechanisms of binding of S. enterica to vegetables such as salad are only poorly understood. We established an experimental model system to systematically investigate the role of adhesive structures of S. enterica serovar Typhimurium in binding to corn salad leaves. The contributions of all members of the complex adhesiome, flagella, and O-antigen were evaluated. We identified that Saf fimbriae, type 1 secretion system-secreted BapA, an intact LPS, and flagella-mediated motility contribute to adhesion of Salmonella to corn salad leaves. These results will enable future investigations on factors contributing to contamination of vegetables under agricultural conditions.

scholarly journals Factors Required for Adhesion of Salmonella enterica Serovar Typhimurium to Corn Salad (Valerianella locusta)

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Laura Elpers ◽  
Juliane Kretzschmar ◽  
Sean-Paul Nuccio ◽  
Andreas J. Bäumler ◽  
Michael Hensel
Keyword(s):  
Salmonella Enterica ◽  
Fresh Produce ◽  
Animal Origin ◽  
Synthetic Approach ◽  
Secretion Systems ◽  
Surface Binding ◽  
Minimally Processed ◽  
Content Type ◽  
Food Of Animal Origin ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica is a foodborne pathogen often leading to gastroenteritis and is commonly acquired by consumption of contaminated food of animal origin. However, frequency of outbreaks linked to the consumption of fresh or minimally processed food of nonanimal origin is increasing. New infection routes of S. enterica by vegetables, fruits, nuts, and herbs have to be considered. This leads to special interest in S. enterica interactions with leafy products, e.g., salads, that are mainly consumed in a minimally processed form. The attachment of S. enterica to salad is a crucial step in contamination, but little is known about the bacterial factors required and mechanisms of adhesion. S. enterica possesses a complex set of adhesive structures whose functions are only partly understood. Potentially, S. enterica may deploy multiple adhesive strategies for adhering to various salad species and other vegetables. In this study, we systematically analyzed the contributions of the complete adhesiome, of lipopolysaccharide (LPS), and of flagellum-mediated motility of S. enterica serovar Typhimurium (STM) in adhesion to Valerianella locusta (corn salad). We deployed a reductionist, synthetic approach to identify factors involved in the surface binding of STM to leaves of corn salad, with particular regard to the expression of all known adhesive structures, using the Tet-on system. This work reveals the contribution of Saf fimbriae, type 1 secretion system-secreted BapA, an intact LPS, and flagellum-mediated motility of STM in adhesion to corn salad leaves. IMPORTANCE Transmission of gastrointestinal pathogens by contaminated fresh produce is of increasing relevance to human health. However, the mechanisms of contamination of, persistence on, and transmission by fresh produce are poorly understood. We investigated the contributions of the various adhesive structures of STM to the initial event in transmission, i.e., binding to the plant surface. A reductionist system was used that allowed experimentally controlled surface expression of individual adhesive structures and analyses of the contribution to binding to leave surfaces of corn salad under laboratory conditions. The model system allowed the determination of the relative contributions of fimbrial and nonfimbrial adhesins, the type 3 secretion systems, the O antigen of lipopolysaccharide, the flagella, and chemotaxis of STM to binding to corn salad leaves. Based on these data, future work could reveal the mechanism of binding and the relevance of interaction under agricultural conditions.

scholarly journals Factors required for adhesion of Salmonella enterica serovar Typhimurium to lettuce (Lactuca sativa)

2020 ◽  
Author(s):  
Laura Elpers ◽  
Michael Hensel
Keyword(s):  
Lactuca Sativa ◽  
Salmonella Enterica ◽  
Fresh Produce ◽  
Animal Origin ◽  
Plant Colonization ◽  
Synthetic Approach ◽  
Surface Binding ◽  
Minimal Processing ◽  
Gastrointestinal Pathogens ◽  
Serovar Typhimurium

AbstractSalmonella enterica serovar Typhimurium (STM) is a major cause of food-borne gastroenteritis. Recent outbreaks of infections by STM are often associated with non-animal related food, i.e. vegetables, fruits, herbs, sprouts and nuts. One main problem related to consumption of fresh produce is the minimal processing, especially for leafy salads such as corn salad, rocket salad, or lettuce. In this study, we focused on lettuce (Lactuca sativa) which is contaminated by STM at higher rates compared to corn salad, resulting in prolonged persistence. We previously described the contribution of Saf fimbriae, type 1 secretion system (T1SS)-secreted BapA, intact LPS, and flagella-mediated motility to adhesion to corn salad leaves. We systematically analyzed factors contributing to adhesion of STM to lettuce leaves. We used the previously established reductionist, synthetic approach to identify factors that contribute to the surface binding of STM to leaves of lettuce by expressing all known adhesive structure by the Tet-on system. The analyses revealed contributions of Lpf fimbriae, Sti fimbriae, autotransported adhesin MisL, T1SS-secreted BapA, intact LPS, and flagella-mediated motility to adhesion of STM to lettuce leaves. In addition, we identified BapA is a potential adhesin involved in binding to corn salad and lettuce leaf surfaces.ImportanceGastrointestinal pathogens can be transmitted by animal products, as well as by fresh produce of non-animal origin. The numbers of outbreaks by fresh produce contaminated with gastrointestinal pathogens are increasing, and underline the relevance to human health. The mechanisms involved in the colonization of, persistence on, and transmission by fresh produce are poorly understood and have to be part of further research. Here, we investigated the contribution of adhesive factors of STM in the initial phase of plant colonization, i.e. the binding to the plant surface. Usage of a reductionist, synthetic approach including the controlled surface expression of specific adhesive structures of STM, one at a time, allowed the determination of relevant fimbrial and non-fimbrial adhesins, the O-antigen of lipopolysaccharide, the flagella, and chemotaxis to binding to lettuce leaves.

scholarly journals Prevalence of Salmonella spp. in layer and broiler farms in Palestine in 2018, with special emphasis on Salmonella enterica serovar Enteritidis

2021 ◽  
Vol 72 (1) ◽  
pp. 2723
Author(s):  
S ABUSEIR ◽  
M ABED AL-DAYM ◽  
G ADWAN ◽  
N KHRAIM
Keyword(s):  
Public Health ◽  
Salmonella Enterica ◽  
Foodborne Pathogen ◽  
Egg Laying ◽  
Poultry Meat ◽  
Animal Origin ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Salmonella Spp ◽  
Palestinian Territories ◽  
Food Of Animal Origin

Salmonella spp. are one of a major public health concerns worldwide, as well as it is the most frequently isolated foodborne pathogen. Human illness with Salmonella spp. is often due to the consumption of contaminated food of animal origin such as eggs or their products and poultry meat. The prevalence of this pathogen in egg-laying poultry farms and in broiler farms is an important public health risk factor. Salmonella enterica serovar Enteritidis has been the major cause of foodborne salmonellosis in humans. Data on the prevalence of Salmonella spp. in the Palestinian territories’ poultry flocks is lacking. The objective of this study was to investigate the prevalence of Salmonella spp. in local layer and broiler flocks, and to find out the rate of S. Enteritidis among the isolated samples. A total of 1180 cloacal swabs were collected from several layer and broiler farms from different locations in the West Bank, Palestine. Identification of Salmonella spp. was carried out using conventional and serological methods. Molecular methods using Polymerase Chain Reaction was used for confirmation of Salmonella spp., and to detect the presence of S. Enteritidis among the isolated Salmonella spp. Results of the current study showed that, the rate of Salmonella spp. in the sample tested from layer and broiler farms was 10.7% (65/608) and 4.7% (27/572), respectively. In addition, the prevalence rate of S. Enteritidis among other Salmonella spp. was 0.0% and 14.8% for layer and broiler farms, respectively. It is highly recommended that further studies should be conducted, including high number of samples with serotyping and molecular characterization of the positive samples.

Identification of Salmonella enterica Serovar Typhimurium Using Specific PCR Primers Obtained by Comparative Genomics in Salmonella Serovars

2006 ◽  
Vol 69 (7) ◽  
pp. 1653-1661 ◽  
Author(s):  
H. J. KIM ◽  
S. H. PARK ◽  
T. H. LEE ◽  
B. H. NAHM ◽  
Y. H. CHUNG ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Salmonella Enterica ◽  
Target Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Foodborne Pathogen ◽  
Pcr Primers ◽  
Genomic Sequences ◽  
Local Alignment ◽  
Serovar Typhimurium ◽  
Salmonella Serovars

Salmonella enterica serovar Typhimurium is a major foodborne pathogen throughout the world. Until now, the specific target genes for the detection and identification of serovar Typhimurium have not been developed. To determine the specific probes for serovar Typhimurium, the genes of serovar Typhimurium LT2 that were expected to be unique were selected with the BLAST (Basic Local Alignment Search Tool) program within GenBank. The selected genes were compared with 11 genomic sequences of various Salmonella serovars by BLAST. Of these selected genes, 10 were expected to be specific to serovar Typhimurium and were not related to virulence factor genes of Salmonella pathogenicity island or to genes of the O and H antigens of Salmonella. Primers for the 10 selected genes were constructed, and PCRs were evaluated with various genomic DNAs of Salmonella and non-Salmonella strains for the specific identification of Salmonella serovar Typhimurium. Among all the primer sets for the 10 genes, STM4497 showed the highest degree of specificity to serovar Typhimurium. In this study, a specific primer set for Salmonella serovar Typhimurium was developed on the basis of the comparison of genomic sequences between Salmonella serovars and was validated with PCR. This method of comparative genomics to select target genes or sequences can be applied to the specific detection of microorganisms.

Responding to the increasing global demand for animal products: implications for the livelihoods of livestock producers in developing countries

2004 ◽  
Vol 33 ◽  
pp. 1-35 ◽  
Author(s):  
D. Thomas ◽  
D. Rangnekar
Keyword(s):  
Developing Countries ◽  
Agricultural Production ◽  
Agricultural Land ◽  
Livestock Production ◽  
Animal Origin ◽  
Forage Crops ◽  
Animal Products ◽  
Food Of Animal Origin ◽  
Global Demand

Livestock production currently accounts for some 40% of the gross value of world agricultural production, and its share is rising (FAO, 2002). Livestock production is the largest user of agricultural land; directly through grazing of pastures and indirectly through the production of forage crops and other feeds. Over the next 20 years, there will be a massive increase in demand for food of animal origin in developing countries, and this increase will be greater than for either the major cereals or roots and tubers (IFPRI, 1995; Delgado et al., 1999).

scholarly journals Citrobacter braakii Yield False-Positive Identification as Salmonella, a Note of Caution

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2177
Author(s):  
Joanna Pławińska-Czarnak ◽  
Karolina Wódz ◽  
Magdalena Kizerwetter-Świda ◽  
Tomasz Nowak ◽  
Janusz Bogdan ◽  
...  
Keyword(s):  
False Positive ◽  
Salmonella Enterica ◽  
Meat Products ◽  
Animal Origin ◽  
Biochemical Tests ◽  
Salmonella Spp ◽  
Isolation And Identification ◽  
False Positive Identification ◽  
Food Of Animal Origin ◽  
Meat Samples

Background: Globally, Salmonella enterica is one of the leading causes of foodborne illness in humans. Food of animal origin is obligatorily tested for the presence of this pathogen. Unfortunately, in meat and meat products, this is often hampered by the presence of background microbiota, which may present as false-positive Salmonella. Methods: For the identification of Salmonella spp. from meat samples of beef, pork, and poultry, the authorized detection method is PN-EN ISO 6579-1:2017-04 with the White–Kauffmann–Le Minor scheme, two biochemical tests: API 20E and VITEK II, and a real-time PCR-based technique. Results: Out of 42 presumptive strains of Salmonella, 83.3% Salmonella enterica spp. enterica, 14.3% Citrobacter braakii, and 12.4% Proteus mirabilis were detected from 180 meat samples. Conclusions: Presumptive strains of Salmonella should be identified based on genotypic properties such as DNA-based methods. The aim of this study was the isolation and identification of Salmonella spp. from miscellaneous meat sorts: beef, pork, and poultry.

scholarly journals The fimYZ Genes Regulate Salmonella enterica Serovar Typhimurium Invasion in Addition to Type 1 Fimbrial Expression and Bacterial Motility

2005 ◽  
Vol 73 (3) ◽  
pp. 1377-1385 ◽  
Author(s):  
M. Aaron Baxter ◽  
Bradley D. Jones
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Protein Interactions ◽  
Salmonella Enterica ◽  
Negative Regulator ◽  
Invasive Phenotype ◽  
Environmental Signals ◽  
Bacterial Physiology ◽  
Serovar Typhimurium

ABSTRACT An important step in Salmonella enterica serovar Typhimurium virulence is the ability to invade the intestinal epithelium. The invasion process requires a large number of genes encoded on Salmonella pathogenicity island 1 (SPI-1) at centisome 63 as well as genes located in other positions throughout the chromosome. Expression of the invasive phenotype is tightly regulated by environmental cues that are processed by a complex regulatory scheme. A central player in the invasion regulatory pathway is the HilA protein, which is transcriptional activator belonging to the OmpR/ToxR family. A number of positive regulators (hilC, hilD, fis, sirA/barA, csrAB, phoBR, fadD, envZ/ompR, and fliZ) and negative regulators (hha, hilE, lon, ams, phoP c and pag) have been identified that are able to alter expression of hilA transcription. Recent work has found that hilA transcription requires the HilD protein for activation. Other work has emphasized the importance of HilE as a negative regulator of hilA. Overexpression of hilE superrepresses hilA transcription, as well as the invasive phenotype. Two-hybrid experiments suggest that HilE exerts its regulatory influence on hilA through protein-protein interactions with HilD as the protein does not bind to the hilA promoter nor does it affect hilD transcription. As it seems likely that hilE plays an important role in translating environmental signals into invasion gene regulation, we have attempted to identify how the hilE gene itself is regulated. Our results indicate that the fimYZ genes, response regulatory proteins involved in type 1 fimbrial gene expression and recently implicated in motility gene regulation, are important activators of hilE expression. These findings indicate that invasion gene expression is coregulated with motility and adherence and provide experimental evidence that the expression of these virulence phenotypes is a subset of the overall regulation of bacterial physiology.

scholarly journals Molecular Epidemiology of Salmonella Enterica Serovar Saintpaul Isolated from Animals, Food, and Humans in 12 European Countries

2012 ◽  
Vol 56 (4) ◽  
pp. 459-466 ◽  
Author(s):  
Dariusz Wasyl ◽  
Magdalena Zając ◽  
Derek J. Brown ◽  
Henry Kuronen ◽  
Kim Van Der Zwaluw ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Pulsed Field Gel Electrophoresis ◽  
European Countries ◽  
Animal Origin ◽  
Potential Threat ◽  
Food Of Animal Origin ◽  
Control Programmes ◽  
High Degree ◽  
Pfge Profiles

Abstract The molecular epidemiological relationship among isolates of Salmonella enterica serovar (S.) Saintpaul, which was identified in animals, food, and humans in several EU countries, was investigated. Pulsed-field gel electrophoresis (PFGE) revealed a high degree of genetic diversity (82 XbaI PFGE profiles with 42.6% similarity) among 159 S. Saintpaul isolates from animals (n=91), food of animal origin (n=29), and humans (n=36) in 12 European countries during 2005 to 2009. Most frequent profiles (n=12) comprised almost 50% of the tested isolates. Profiles obtained in isolates from a single source within a particular geographical region or particular period of time were indistinguishable or closely related. Turkeys were confirmed as the major reservoir for S. Saintpaul. Indistinguishable PFGE profiles were identified in up to 19 isolates from turkey breeding and fattening flocks and food over the study period. Other animals, including food and pets, may also contribute to S. Saintpaul spread. International trade of animals and food, as well as travelling contributes to the spread of a specific clone to different geographical areas. Although control programmes in breeding turkey flocks, together with improved biosecurity, may interrupt the major transmission routes, it was concluded that S. Saintpaul will continue to represent a potential threat to human health.

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