Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Comparative analysis of biofilm formation by Bacillus cereus reference strains and undomesticated food isolates and the effect of free iron
Hayrapetyan, H. ; Muller, L.K. ; Tempelaars, M.H. ; Abee, T. ; Nierop Groot, M.N. - \ 2015
International Journal of Food Microbiology 200 (2015). - ISSN 0168-1605 - p. 72 - 79.
pseudomonas-aeruginosa - stainless-steel - processing environments - twitching motility - adhesion - surface - attachment - contamination - typhimurium - sporulation
Biofilm formation of Bacillus cereus reference strains ATCC 14579 and ATCC 10987 and 21 undomesticated food isolates was studied on polystyrene and stainless steel as contact surfaces. For all strains, the biofilm forming capacity was significantly enhanced when in contact with stainless steel (SS) as a surface as compared to polystyrene (PS). For a selection of strains, the total CFU and spore counts in biofilms were determined and showed a good correlation between CFU counts and total biomass of these biofilms. Sporulation was favoured in the biofilm over the planktonic state. To substantiate whether iron availability could affect B. cereus biofilm formation, the free iron availability was varied in BHI by either the addition of FeCl3 or by depletion of iron with the scavenger 2,2-Bipyridine. Addition of iron resulted in increased air-liquid interface biofilm on polystyrene but not on SS for strain ATCC 10987, while the presence of Bipyridine reduced biofilm formation for both materials. Biofilm formation was restored when excess FeCl3 was added in combination with the scavenger. Further validation of the iron effect for all 23 strains in microtiter plate showed that fourteen strains (including ATCC10987) formed a biofilm on PS. For eight of these strains biofilm formation was enhanced in the presence of added iron and for eleven strains it was reduced when free iron was scavenged. Our results show that stainless steel as a contact material provides more favourable conditions for B. cereus biofilm formation and maturation compared to polystyrene. This effect could possibly be linked to iron availability as we show that free iron availability affects B. cereus biofilm formation.
Establishing streptomycin epidemiological cut-off values for Salmonella and Escherichia coli. Microbial Drug Resistance
Garcia-Migura, L. ; Sunde, M. ; Karlsmose, S. ; Veldman, K.T. ; Schroeter, A. ; Guerra, B. ; Granier, S.A. ; Perrin-Guyomard, A. ; Gicquel-Bruneau, M. ; Franco, A. ; Englund, S. ; Teale, C. ; Heiska, H. ; Clemente, L. ; Boerlin, P. ; Moreno, M.A. ; Daignault, D. ; Mevius, D.J. ; Hendriksen, R.S. ; Aarestrup, F.M. - \ 2012
Microbial Drug Resistance-Mechanisms Epidemiology and Disease 18 (2012)1. - ISSN 1076-6294 - p. 88 - 93.
antimicrobial susceptibility - resistance genes - food animals - protein s12 - integrons - bacteria - typhimurium - countries - products - class-1
This study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ECOFF) for Escherichia coli and Salmonella spp. A total of 236 Salmonella enterica and 208 E. coli isolates exhibiting MICs between 4 and 32¿mg/L were selected from 12 countries. Isolates were investigated by polymerase chain reaction for aadA, strA, and strB streptomycin resistance genes. Out of 236 Salmonella isolates, 32 (13.5%) yielded amplicons for aadA (n¿=¿23), strA (n¿=¿9), and strB (n¿=¿11). None of the 60 Salmonella isolates exhibiting MIC 4¿mg/L harbored resistance genes. Of the Salmonella isolates exhibiting MICs 8¿mg/L, 16¿mg/L, and 32¿mg/L, 1.6%, 15%, and 39%, respectively, tested positive for one or more genes. For most monitoring programs, the streptomycin ECOFF for Salmonella is wild type (WT) =32 or =16¿mg/L. A cut-off value of WT =32¿mg/L would have misclassified 13.5% of the strains as belonging to the WT population, since this proportion of strains harbored resistance genes and exhibited MICs =32¿mg/L. Out of 208 E. coli strains, 80 (38.5%) tested positive for aadA (n¿=¿69), strA (n¿=¿18), and strB (n¿=¿31). Of the E. coli isolates exhibiting MICs of 4¿mg/L, 8¿mg/L, 16¿mg/L, and 32¿mg/L, 3.6%, 17.6%, 53%, and 82.3%, respectively, harbored any of the three genes. Based on the European Committee on Antimicrobial Susceptibility Testing guidelines (ECOFF =16¿mg/L), 25% of the E. coli strains presenting MIC =16¿mg/L would have been incorrectly categorized as belonging to the WT population. The authors recommend an ECOFF value of WT =16¿mg/L for Salmonella and WT =8¿mg/L for E. coli.
Evaluation of Eight Different Cephalosporins for Detection of Cephalosporin Resistance in Salmonella enterica and Escherichia coli
Aarestrup, F.M. ; Hasman, H. ; Veldman, K.T. ; Mevius, D.J. - \ 2010
Microbial Drug Resistance-Mechanisms Epidemiology and Disease 16 (2010)4. - ISSN 1076-6294 - p. 253 - 261.
spectrum beta-lactamases - molecular characterization - antimicrobial resistance - klebsiella-pneumoniae - typhimurium - animals - denmark
This study evaluates the efficacy of eight different cephalosporins for detection of cephalosporin resistance mediated by extended spectrum beta-lactamases (ESBL) and plasmidic AmpC beta-lactamases in Salmonella and Escherichia coli. A total of 138 E. coli and 86 Salmonella isolates with known beta-lactamase genes were tested for susceptibility toward cefoperazone, cefotaxime, cefpodoxime, cefquinome, ceftazidime, ceftiofur, ceftriaxone, and cefuroxime using minimum inhibitory concentration determinations and disc diffusion. The collection consisted of 84 ampicillin-susceptible, 57 ampicillin-resistant but cephalosporin-susceptible, 56 ESBL isolates and 19 isolates with plasmidic AmpC, as well as 10 ampC hyper-producing E. coli. The minimum inhibitory concentration distributions and zone inhibitions varied with the tested compound. Ampicillin-resistant isolates showed reduced susceptibility to the cephalosporins compared to ampicillin-susceptible isolates. Cefoperazone, cefquinome, and cefuroxime were not useful in detecting isolates with ESBL or plasmidic AmpC. The best substances for detection were cefotaxime, cefpodoxime, and ceftriaxone, whereas ceftazidime and ceftiofur were not as efficient. Ceftriaxone may be the recommended substance for monitoring because of some ability in separating ampC hyper-producing E. coli from ESBL and plasmidic AmpC isolates
Increased detection of extended spectrum beta-lactamase producing Salmonella enterica and Escherichia coli isolates from poultry
Dierikx, C.M. ; Essen-Zandbergen, A. van; Veldman, K.T. ; Smith, H.E. ; Mevius, D.J. - \ 2010
Veterinary Microbiology 145 (2010)3-4. - ISSN 0378-1135 - p. 273 - 278.
gram-negative bacteria - resistance plasmid - ctx-m - enterobacteriaceae - animals - cephalosporins - identification - typhimurium - strains - genes
To gain more information on the genetic basis of the rapid increase in the number of isolates exhibiting non-wild type Minimum Inhibitory Concentrations (MICs) for cefotaxime observed since 2003, beta-lactamase genes of 22 Salmonella enterica and 22 Escherichia coli isolates from broilers in 2006 showing this phenotype were characterized by miniaturized micro-array, PCR and DNA-sequencing. Presence and size of plasmids were determined by S1-digest pulsed-field gel electrophoresis and further characterized by PCR-based replicon typing. Transfer of resistance plasmids was tested by conjugation and transformation experiments. To link resistance genes and plasmid type, Southern blot hybridization experiments were conducted. In 42 isolates, five (blaCTX-M-1, blaCTX-M-2, blaTEM-20, blaTEM-52, blaSHV-2) different extended spectrum beta-lactamase (ESBL)-genes and two (blaACC-1, blaCMY-2) AmpC-genes were present. Three of the detected ESBL-genes (blaCTX-M-1, blaTEM-52 and blaCTX-M-2) were located on similar types of plasmids (IncI1 and IncHI2/P) in both E. coli and Salmonella. Two other detected ESBL- and AmpC-genes blaSHV-2 and blaCMY-2 respectively (on IncK plasmids), were only found in E. coli, whereas the AmpC-gene blaACC-1 (on non-typable plasmids), and the ESBL-gene blaTEM-20 (on IncI1 plasmids), were only detected in Salmonella. In two isolates, no ESBL- or AmpC-gene could be detected through these methods. The increase in the number of E. coli and S. enterica isolates from the gastro-intestinal tract of broilers exhibiting non-wild type MICs for cefotaxime is mainly due to an increase in IncI1 plasmids containing blaCTX-M-1. The reason for the successful spread of this plasmid type in these species is not yet understood.
Virulotyping and antimicrobial resistance typing of Salmonella enterica serovars relevant to human health in Europe
Huehn, S. ; Ragione, R.M. La; Anjum, F.M. ; Saunders, M. ; Woodward, M. ; Bunge, C. ; Helmuth, R. ; Hauser, E. ; Guerra, B. ; Beutlich, J. ; Brisabois, A. ; Peters, T. ; Svensson, L. ; Madajczak, G. ; Litrup, E. ; Imre, A. ; Herrera-Leon, S. ; Mevius, D.J. ; Newell, D.G. ; Malrony, B. - \ 2010
Foodborne Pathogens and Disease 7 (2010). - ISSN 1535-3141 - p. 523 - 535.
complete genome sequence - quinolone resistance - serotype enteritidis - peyers-patches - typhimurium - identification - expression - integrons - strains - gene
The combination of virulence gene and antimicrobial resistance gene typing using DNA arrays is a recently developed genomics-based approach to bacterial molecular epidemiology. We have now applied this technology to 523 Salmonella enterica subsp. enterica strains collected from various host sources and public health and veterinary institutes across nine European countries. The strain set included the five predominant Salmonella serovars isolated in Europe (Enteritidis, Typhimurium, Infantis, Virchow, and Hadar). Initially, these strains were screened for 10 potential virulence factors (avrA, ssaQ, mgtC, siiD, sopB, gipA, sodC1, sopE1, spvC, and bcfC) by polymerase chain reaction. The results indicated that only 14 profiles comprising these genes (virulotypes) were observed throughout Europe. Moreover, most of these virulotypes were restricted to only one (n = 9) or two (n = 4) serovars. The data also indicated that the virulotype did not vary significantly with host source or geographical location. Subsequently, a representative subset of 77 strains was investigated using a microarray designed to detect 102 virulence and 49 resistance determinants. The results confirmed and extended the previous observations using the virulo-polymerase chain reaction screen. Strains belonging to the same serovar grouped together, indicating that the broader virulence-associated gene complement corresponded with the serovar. There were, however, some differences in the virulence gene profiles between strains belonging to an individual serovar. This variation occurred primarily within those virulence genes that were prophage encoded, in fimbrial clusters or in the virulence plasmid. It seems likely that such changes enable Salmonella to adapt to different environmental conditions, which might be reflected in serovar-specific ecology. In this strain subset a number of resistance genes were detected and were serovar restricted to a varying degree. Once again the profiles of those genes encoding resistance were similar or the same for each serovar in all hosts and countries investigated
Transition of enteropathogenic and saprotrophic bacteria in the cycle: Animals-excrement-soil-plants-animals
Kupriyanov, A.A. ; Semenov, A.M. ; Bruggen, A.H.C. van - \ 2010
Biology Bulletin / Russian Academy of Sciences 37 (2010)3. - ISSN 1062-3590 - p. 263 - 267.
escherichia-coli o157-h7 - cattle - manure - typhimurium
The possibility of transition of saprotrophic and enteropathohenic bacterial populations following the chain of naturally related habitats-fodder-animal gastrointestinal tract (GIT)-animals excrement-soil-plants and again animals with a cyclic formation-has been investigated quantitatively. All bacteria used in the experiments have been shown to successfully overcome all the mechanical, physical-chemical, and biological barriers in the food chain and to come out into the environment with a quite high number. It has been demonstrated that the same bacterial population can pass the whole cycle without additional introduction of similar populations from the outside
Physiological and molecular response of Lactuca sativa to colonization by Salmonella enterica serovar Dublin
Klerks, M.M. ; Gent-Pelzer, M.P.E. van; Franz, E. ; Zijlstra, C. ; Bruggen, A.H.C. van - \ 2007
Applied and Environmental Microbiology 73 (2007)15. - ISSN 0099-2240 - p. 4905 - 4914.
escherichia-coli o157-h7 - arabidopsis-thaliana - contaminated manure - salad vegetables - irrigation water - salicylic-acid - tomato plants - bovine manure - enterica - typhimurium
This paper describes the physiological and molecular interactions between the human-pathogenic organism Salmonella enterica serovar Dublin and the commercially available mini Roman lettuce cv. Tamburo. The association of S. enterica serovar Dublin with lettuce plants was first determined, which indicated the presence of significant populations outside and inside the plants. The latter was evidenced from significant residual concentrations after highly efficient surface disinfection (99.81%) and fluorescence microscopy of S. enterica serovar Dublin in cross sections of lettuce at the root-shoot transition region. The plant biomass was reduced significantly compared to that of noncolonized plants upon colonization with S. enterica serovar Dublin. In addition to the physiological response, transcriptome analysis by cDNA amplified fragment length polymorphism analysis also provided clear differential gene expression profiles between noncolonized and colonized lettuce plants. From these, generally and differentially expressed genes were selected and identified by sequence analysis, followed by reverse transcription-PCR displaying the specific gene expression profiles in time. Functional grouping of the expressed genes indicated a correlation between colonization of the plants and an increase in expressed pathogenicity-related genes. This study indicates that lettuce plants respond to the presence of S. enterica serovar Dublin at physiological and molecular levels, as shown by the reduction in growth and the concurrent expression of pathogenicity-related genes. In addition, it was confirmed that Salmonella spp. can colonize the interior of lettuce plants, thus potentially imposing a human health risk when processed and consumed.
Salmonella induces prominent gene expression in rat colon, which is affected by dietary fructo-oligosaccharides
Rodenburg, G.C.H. ; Keijer, J. ; Kramer, E.H.M. ; Roosing, S. ; Vink, C. ; Katan, M.B. ; Meer, R. van der; Bovee-Oudenhoven, I.M.J. - \ 2007
BMC Microbiology 7 (2007). - ISSN 1471-2180 - 36 p.
inflammatory-bowel-disease - gamma-interferon production - epithelial-cells - intestinal colonization - immune-response - host-resistance - messenger-rna - ifn-gamma - in-vitro - typhimurium
Background Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection. Results Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFN¿ and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes. Conclusion We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression.
Differential interaction of Salmonella enterica serovars with lettuce cultivars and plant-microbe factors influencing the colonization efficiency
Klerks, M.M. ; Franz, E. ; Gent-Pelzer, M.P.E. van; Zijlstra, C. ; Bruggen, A.H.C. van - \ 2007
ISME Journal 1 (2007). - ISSN 1751-7362 - p. 620 - 631.
groenten - endofyten - chemotaxis - salmonella - humane pathogenen - plant-microbe interacties - vegetables - endophytes - human pathogens - plant-microbe interactions - escherichia-coli o157-h7 - irrigation water - arabidopsis-thaliana - contaminated manure - tomato plants - bacteria - typhimurium - rhizosphere - pathogen - survival
The availability of knowledge of the route of infection and critical plant and microbe factors influencing the colonization efficiency of plants by human pathogenic bacteria is essential for the design of preventive strategies to maintain safe food. This research describes the differential interaction of human pathogenic Salmonella enterica with commercially available lettuce cultivars. The prevalence and degree of endophytic colonization of axenically grown lettuce by the S. enterica serovars revealed a significant serovar¿cultivar interaction for the degree of colonization (S. enterica CFUs per g leaf), but not for the prevalence. The evaluated S. enterica serovars were each able to colonize soil-grown lettuce epiphytically, but only S. enterica serovar Dublin was able to colonize the plants also endophytically. The number of S. enterica CFU per g of lettuce was negatively correlated to the species richness of the surface sterilized lettuce cultivars. A negative trend was observed for cultivars Cancan and Nelly, but not for cultivar Tamburo. Chemotaxis experiments revealed that S. enterica serovars actively move toward root exudates of lettuce cultivar Tamburo. Subsequent micro-array analysis identified genes of S. enterica serovar Typhimurium that were activated by the root exudates of cultivar Tamburo. A sugar-like carbon source was correlated with chemotaxis, while also pathogenicity-related genes were induced in presence of the root exudates. The latter revealed that S. enterica is conditioned for host cell attachment during chemotaxis by these root exudates. Finally, a tentative route of infection is described that includes plant-microbe factors, herewith enabling further design of preventive strategies.
Detection of egg yolk antibodies reflecting Salmonella enteritidis infections using a surface plasmon resonance biosensor
Thomas, M.E. ; Bouma, A. ; Eerden, E. van; Landman, W.J.M. ; Knapen, F. van; Stegeman, J.A. ; Bergwerff, A.A. - \ 2006
Journal of Immunological Methods 315 (2006)1-2. - ISSN 0022-1759 - p. 68 - 74.
laying hens - typhimurium - chickens - elisa - assay - immunosensor - netherlands - antigens - serum
A surface plasmon resonance (SPR) biosensor assay was developed on the basis of a lipopolysaccharide antigen of Salmonella enterica serovar enteritidis (S. enterica serovar enteritidis) to detect egg yolk antibodies against S. enterica serovar enteritidis. This biosensor assay was compared to two commercial ELISA kits based on LPS antigen and flagellar antigen. A number of 163 egg yolk and combined egg white and yolk samples from chickens experimentally infected with S. enterica serovar enteritidis and 90 egg yolk and combined egg white and yolk samples from uninfected chickens were analyzed. Receiver operating characteristic analysis of the data calculated a diagnostic sensitivity of 82% and a diagnostic specificity of 100%. The within-day coefficient of variation of a positive internal-control egg yolk was 1%. The SPR biosensor assay was able to detect antibodies in a significantly higher percentage of known positive samples than the commercial ELISA's. The anticipated use of the SPR biosensor assay is to determine the S. enterica serovar enteritidis serostatus of non-vaccinated layer hens
Survival, elongation, and elevated tolerance of Salmonella enterica serovar Enteritidis at reduced water activity
Kieboom, J. ; Kusumaningrum, H.D. ; Tempelaars, M.H. ; Hazeleger, W.C. ; Abee, T. ; Beumer, R.R. - \ 2006
Journal of Food Protection 69 (2006)11. - ISSN 0362-028X - p. 2681 - 2686.
osmotic-stress - cell-division - single-cell - typhimurium - microorganisms - temperatures - bacteria - glycine - heat - acid
Growing microorganisms on dry surfaces, which results in exposure to low water activity (aw), may change their normal morphology and physiological activity. In this study, the morphological changes and cell viability of Salmonella enterica serovar Enteritidis challenged to low aw were analyzed. The results indicated that exposure to reduced aw induced filamentation of the cells. The amount of filamentous cells at aw 0.94 was up to 90% of the total number of cells. Surviving filamentous cells maintained their membrane integrity after exposure to low aw for 21 days. Furthermore, cells prechallenged to low aw, obtained with an ionic humectant, demonstrated higher resistance to sodium hypochlorite than control cells. These resistant cells are able to survive disinfection more efficiently and can therefore cause contamination of foods coming in contact with surfaces. This points to the need for increased attention to cleaning of surfaces in household environments and disinfection procedures in processing plants
Early host gene expression responses to a Salmonella infection in the intestine of chickens with different genetic background
Hemert, S. van; Hoekman, A.J.W. ; Smith, M.A. ; Rebel, J.M.J. - \ 2006
Comparative Biochemistry and Physiology. D, Genomics and Proteomics 1 (2006)3. - ISSN 1744-117X - p. 292 - 299.
actin cytoskeleton - epithelial-cells - typhimurium - enteritidis - protein - lines - induction - family - inflammation - heterophils
So far the responses of chickens to Salmonella have not been studied in vivo on a whole genome-wide scale. Furthermore, the influence of the host genetic background on gene expression responses is unknown. In this study gene expression profiles in the chicken (Gallus gallus) intestine of two genetically different chicken lines were compared, 24 h after a Salmonella enteritidis inoculation in 1-day-old chicks. The two chicken lines differed in the severity of the systemic infection. For gene expression profiles, a whole genome oligonucleotide array and a cDNA microarray were used to compare both platforms. Genes upregulated in both chicken lines after the Salmonella infection had a function in the innate immune system or in wound healing. Genes regulated after the Salmonella infection in one chicken line encoded proteins involved in inflammation, or with unknown functions. In the other chicken line upregulated genes encoded proteins involved in acute phase response, the fibrinogen system, actin polymerisation, or with unknown functions. Some of the host gene responses found in this study are not described before as response to a bacterial infection in the intestine. The two chicken lines reacted with different intestinal gene responses to the Salmonella infection, implying that it is important to use chickens with different genetic background to study gene expression responses
Comparison of Methods of Extracting Salmonella enterica Serovar Enteritidis DNA from Environmental Substrates and Quantification of Organisms by Using a General Internal Procedural Control
Klerks, M.M. ; Bruggen, A.H.C. van; Zijlstra, C. ; Donnikov, M. ; Vos, R. de - \ 2006
Applied and Environmental Microbiology 72 (2006)6. - ISSN 0099-2240 - p. 3879 - 3886.
escherichia-coli o157-h7 - polymerase-chain-reaction - real-time pcr - manure - assay - soil - amplification - typhimurium - outbreak - recovery
This paper compares five commercially available DNA extraction methods with respect to DNA extraction efficiency of Salmonella enterica serovar Enteritidis from soil, manure, and compost and uses an Escherichia coli strain harboring a plasmid expressing green fluorescent protein as a general internal procedural control. Inclusion of this general internal procedural control permitted more accurate quantification of extraction and amplification of S. enterica serovar Enteritidis in these samples and reduced the possibility of false negatives. With this protocol it was found that the optimal extraction method differed for soil (Mobio soil DNA extraction kit), manure (Bio101 soil DNA extraction kit), and compost (Mobio fecal DNA extraction kit). With each method, as little as 1.2 x 103 to 1.8 x 103 CFU of added serovar Enteritidis per 100 mg of substrate could be detected by direct DNA extraction and subsequent S. enterica-specific TaqMan PCR. After bacterial enrichment, as little as 1 CFU/100 mg of original substrate was detected. Finally, the study presents a more accurate molecular analysis for quantification of serovar Enteritidis initially present in soil or manure using DNA extraction and TaqMan PCR
Health and growth of veal calves fed milk replacers with or without probiotics
Timmerman, H.M. ; Mulder, L. ; Everts, H. ; Espen, D.C. van; Wal, E. van der; Klaassen, G. ; Rouwers, S.M.G. ; Hartemink, R. ; Rombouts, F.M. ; Beynen, A.C. - \ 2005
Journal of Dairy Science 88 (2005)6. - ISSN 0022-0302 - p. 2154 - 2165.
antibiotic-associated diarrhea - lactic-acid bacteria - lactobacillus-gg - prevention - infection - stress - supplementation - malabsorption - typhimurium - performance
Four experiments with 1-wk-old veal calves were conducted to assess the influence of probiotics on growth and health indicators. In experiments 1 and 2, the liquid probiotic supplements were administered daily from experimental d 1 to 15. The treatment period in experiments 3 and 4 was extended to 56 d. The probiotics used were a multispecies probiotic (MSPB) containing different probiotic species of human origin, or a calf-specific probiotic (CSPB) containing 6 Lactobacillus species isolated from calf feces and selected on the basis of a combination of characteristics. When the data for the 4 experiments were pooled, the probiotics enhanced growth rate during the first 2 wk. During the 8-wk experimental period, average daily gain and feed efficiency were significantly improved in the probiotic-treated groups. The MSPB-induced increase in weight gain was greater when the control calves were considered less healthy based on a health score (an index of diarrhea and therapeutic treatments). Probiotic treatment tended to diminish mortality. The CSPB treatment reduced the incidence of diarrhea and the fecal counts of coliforms. When therapeutic treatment was intensive in the control calves, the ingestion of probiotics reduced the percentage of calves that required therapy and the amount of treatments needed against digestive or respiratory diseases. There was no clear difference in the efficiency of the MSPB and CSPB preparations. Further research is necessary to identify underlying mechanisms and to evaluate the potential of probiotics to improve respiratory health in veal calf production.
Effect of acidified feed on suscebtibility of broiler chickens to intestinal infection by Campylobacter and Salmonella
Heres, L. ; Engel, B. ; Urlings, H.A.P. ; Wagenaar, J.A. ; Knapen, F. van - \ 2004
Veterinary Microbiology 99 (2004)3-4. - ISSN 0378-1135 - p. 259 - 267.
fermented liquid feed - formic-acid - airborne transmission - propionic-acid - chicks - enteritidis - colonization - typhimurium - performance - netherlands
Consumption of poultry meat is associated with human Campylobacter and Salmonella infections. One way to control the presence of these bacteria in broiler flocks is to make chickens less susceptible for colonisation. Acidification of feed may be a tool to reduce the Campylobacter and Salmonella carriage in broiler chickens. In the present experiments an acidified feed with high levels of organic acid, 5.7% lactic acid and 0.7% acetic acid, was applied. In an in vitro experiment the reduction or growth of Campylobacter and Salmonella was measured after addition of 107 cfu of these bacteria into a conventional broiler feed, acidified feed and fermented feed, whereas the numbers of Salmonella increased in non-acidified feed. The number of Campylobacter decreased 2¿3 10log cfu. In the acidified and fermented feed a complete reduction of Campylobacter was observed within 20 min, and a total Salmonella reduction started after 1 h, and was complete after 2 h. Subsequently, an in vivo experiment with 100 individually housed broiler chickens showed that chickens fed acidified feed were less susceptible to an infection with Campylobacter than were chickens fed conventional feed. The size of reduction was however limited. The susceptibility for Salmonella colonisation was not affected by acidified feed. It is concluded that the role for acidified feed in the control of Campylobacter and Salmonella is limited
Transmission of Salmonella between broiler chickens fed with fermented liquid feed
Heres, L. ; Urlings, B.A.P. ; Wagenaar, J.A. ; Jong, M.C.M. de - \ 2004
Epidemiology and Infection 132 (2004)1. - ISSN 0950-2688 - p. 107 - 116.
typhimurium - prevalence - virus - enteritidis - population - excretion - infection - movement
In the light of food safety and the control of Salmonella at chicken farms, fermented liquid feed (FLF) was studied. This moistened feed reduced the susceptibility of chickens for Salmonella. To assess the effect of the fermented feed on the transmission of Salmonella between chickens, a transmission experiment was performed. Salmonella shedding was followed within groups of two susceptible chickens together with two previously inoculated chickens. The between-chicken transmission was quantified by calculating a reproduction ratio (R0) and a transmission rate parameter ([beta]). R0 and [beta] in the FLF-treated groups were reduced, but a typical infectious chicken fed with FLF, could on average still infect more than one new infectious case. FLF can therefore reduce the transmission of Salmonella in chicken flocks, but it will not prevent the occurrence of major outbreaks.
A state-transition model for the spread of Salmonella in the pork supply chain
Gaag, M.A. van der; Vos, F. ; Saatkamp, H.W. ; Boven, R.M. van; Beek, P. van; Huirne, R.B.M. - \ 2004
European Journal of Operational Research 156 (2004). - ISSN 0377-2217 - p. 782 - 798.
pigs - transmission - typhimurium - swine
A major food safety issue in pork is Salmonella contamination. A stochastic state-transition simulation model was described to simulate the spread of Salmonella from multiplying through slaughter, with special emphasis for critical control points to prevent or reduce Salmonella contamination. Design of experiments and metamodelling were used for a sensitivity analysis. The finishing stage and the slaughterhouse appeared to be the most important stages in the supply chain to reduce the prevalence of Salmonella contaminated carcasses. (C) 2003 Elsevier B.V. All rights reserved.
Dietary fructo-oligosaccharides and inulin decrease resistance of rats to salmonelle: protective role of calcium
Bruggencate, S.J.M. ten; Bovee-Oudenhoven, I.M.J. ; Lettink-Wissink, M.L.G. ; Katan, M.B. ; Meer, R. van der - \ 2004
Gut 53 (2004). - ISSN 0017-5749 - p. 530 - 535.
chain fatty-acids - mucin secretion - listeria-monocytogenes - human colon - bile-acids - typhimurium - translocation - bifidobacteria - oligofructose - colonization
Background: We have shown recently that rapid fermentable fructo-oligosaccharides (FOS) decreased resistance of rats towards salmonella. It is not known whether inulin ( which is fermented more gradually) has similar effects or whether buffering nutrients can counteract the adverse effects of rapid fermentation. Aims: To compare the effects of dietary inulin and FOS on resistance of rats to Salmonella enterica serovar Enteritidis and to determine whether calcium phosphate counteracts the effects of fermentation. Methods: Male Wistar rats (n = 8 per group) were fed a human "Western style diet''. Diets with 60 g/kg cellulose ( control), FOS, or inulin had either a low ( 30 mmol/kg) or high ( 100 mmol/kg) calcium concentration. After an adaptation period of two weeks, animals were orally infected with 26109 colony forming units of Salmonella enterica serovar Enteritidis. Colonisation of salmonella was determined by quantification of salmonella in caecal contents. Translocation of salmonella was quantified by analysis of urinary nitric oxide metabolites in time. Results: Inulin and FOS decreased intestinal pH and increased faecal lactobacilli and enterobacteria. Moreover, both prebiotics increased the cytotoxicity of faecal water and faecal mucin excretion. Both prebiotics increased colonisation of salmonella in caecal contents and enhanced translocation of salmonella. Dietary calcium phosphate counteracted most of the adverse effects of inulin and FOS. Conclusions: Both inulin and FOS impair resistance to intestinal infections in rats. This impairment is partially prevented by dietary calcium phosphate. The results of the present study await verification in other controlled animal and human studies.
Effect of fermented feed on the susceptibility for campylobacter jejuni infection in broilers with and without concurrent infection with Salmonella enteriditis
Heres, L. ; Engel, B. ; Knapen, F. van; Wagenaar, J.A. ; Urlings, B. - \ 2003
International Journal of Food Microbiology 87 (2003)1-2. - ISSN 0168-1605 - p. 75 - 86.
mucosal competitive-exclusion - lactic-acid - bacteria - poultry - typhimurium - infection - flocks - inhibition - tract
Fermented liquid feed (FLF) protects broiler chickens against colonisation with Salmonella. While Campylobacter causes more disease cases in humans than Salmonella, the effect of FLF on Campylobacter was assessed. The fermented liquid feed is a moistened feed with a high number of lactobacilli, a high concentration of lactic acid, and a pH of 4. In three experiments Campylobacter was orally applied to individually housed 9-day-old broiler chickens. A significant reduction of susceptibility, as determined by cloacal swabs, was observed. At any moment where an animal has not started to shed Campylobacter yet, the probability to start shedding Campylobacter in a subsequent small time interval was nine times as high for the control chickens than for the animals that were fed FLF. FLF did not consistently change the Campylobacter colonisation level in the caeca. It was concluded that FLF could reduce the probability of introduction of Campylobacter in broiler flocks. In an experiment where some chickens were simultaneously inoculated with Salmonella enteritidis and Campylobacter, no interaction on susceptibility or caecal colonisation level was observed.
The occurrence and epidemiology of Salmonella in European pig slaughterhouses
Hald, T. ; Wingstrand, A. ; Swanenburg, M. ; Altrock, A. von; Thorberg, B.M. - \ 2003
Epidemiology and Infection 131 (2003)3. - ISSN 0950-2688 - p. 1187 - 1203.
yersinia-enterocolitica - meat inspection - risk-factors - phage types - typhimurium - carcasses - outbreak - identification - swine - pork
This study was part of an international research project entitled SALINPORK (FAIR CT-950400) initiated in 1996. The objectives were to investigate the occurrence of Salmonella in pig slaughterhouses and to identify risk factors associated with the contamination of pig carcasses. Data was collected from 12 slaughterhouses in five European countries. Isolates were characterized by serotyping, phage typing and antimicrobial susceptibility. In one country, no Salmonella was found. Salmonella was isolated from 5·3% of 3485 samples of pork and from 13·8% of 3573 environmental samples from the seven slaughterhouses in the four remaining countries. The statistical analyses (multi-level logistic regression) indicated that the prevalence was significantly higher during the warmer months and that the environmental contamination increased during the day of slaughter. The polishing (OR 3·74, 95% CI 1·43¿9·78) and pluck removal (OR 3·63, 95% CI 1·66¿7·96) processes were found to contribute significantly to the total carcass contamination, the latter especially if the scalding water also was contaminated. To reduce carcass contamination, it is recommended to ensure sufficiently high temperatures of scalding water (62 °C) and appropriate cleaning and disinfection of the polishing equipment at least once a day in order to reduce the level of carcass contamination and consequently the prevalence of Salmonella in pork
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