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Sample records for salmonella typhimurium causing

  1. Dissemination of clonal Salmonella enterica serovar Typhimurium isolates causing salmonellosis in Mauritius

    DEFF Research Database (Denmark)

    Issack, M. I.; Migura, Lourdes Garcia; Ramsamy, Veemala D.

    2013-01-01

    Salmonella enterica serotype Typhimurium is one of the leading causes of salmonellosis in Mauritius, where it has also been associated with outbreaks of foodborne illness. However, little is known about its molecular epidemiology in the country. This study was therefore undertaken to investigate...

  2. Dissemination of clonal Salmonella enterica serovar Typhimurium isolates causing salmonellosis in Mauritius.

    Science.gov (United States)

    Issack, Mohammad I; Garcia-Migura, Lourdes; Ramsamy, Veemala D; Svendsen, Christina A; Pornruangwong, Srirat; Pulsrikarn, Chaiwat; Hendriksen, Rene S

    2013-07-01

    Salmonella enterica serotype Typhimurium is one of the leading causes of salmonellosis in Mauritius, where it has also been associated with outbreaks of foodborne illness. However, little is known about its molecular epidemiology in the country. This study was therefore undertaken to investigate the clonality and source of Salmonella Typhimurium in Mauritius by studying human, food, and poultry isolates by pulsed-field gel electrophoresis (PFGE) and antibiotic minimum inhibitory concentration determination. Forty-nine isolates collected between 2008 and 2011 were analyzed, including 25 stool isolates from foodborne illness outbreaks and sporadic gastroenteritis cases, four blood isolates, one postmortem colon isolate, 14 food isolates, and five poultry isolates. All isolates were pansusceptible to the 16 antibiotics tested, except for two isolates that were resistant to sulfamethoxazole and trimethoprim. Overall characterization of the isolates by PFGE digested with XbaI and BlnI resulted in eight different patterns. The largest of the clusters in the composite dataset consisted of 20 isolates, including two raw chicken isolates, four poultry isolates, and nine human stool isolates from two outbreaks. A second cluster consisted of 18 isolates, of which 12 originated from human blood and stool samples from both sporadic and outbreak cases. Six food isolates were also found in this cluster, including isolates from raw and grilled chicken, marlin mousse, and cooked pork. One poultry isolate had a closely related PFGE pattern. The results indicate that one clone of Salmonella Typhimurium found in poultry has been causing outbreaks of foodborne illness in Mauritius and another clone that has caused many cases of gastrointestinal illness and bacteremia in humans could also be linked to poultry. Thus, poultry appears to be a major reservoir for Salmonella Typhimurium in Mauritius. Initiating on-farm control strategies and measures against future dissemination may

  3. Salmonella enterica serovars Typhimurium and Enteritidis causing mixed infections in febrile children in Mozambique

    Directory of Open Access Journals (Sweden)

    García V

    2018-01-01

    Full Text Available Vanesa García,1 Inácio Mandomando,2,3 Joaquim Ruiz,4 Silvia Herrera-León,5 Pedro L Alonso,3,4 M Rosario Rodicio1 1Departamento de Biología Funcional, Área de Microbiología, Universidad de Oviedo, Oviedo, Spain; 2Centro de Investigação em Saúde de Manhiça, 3Instituto Nacional de Saúde, Ministério da Saúde, Maputo, Mozambique; 4ISGlobal, Barcelona Centre for International Health Research, Hospital Clínic, Universitat de Barcelona, Barcelona, 5Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain Background and purpose: Invasive nontyphoidal salmonellosis, mostly caused by serovars Typhimurium and Enteritidis of Salmonella enterica, has emerged as a major public health problem in sub-Saharan Africa. The aim of this study was the clinical and microbiological characterization of nontyphoidal salmonellosis episodes affecting febrile children in Mozambique. Patients and methods: The clinical records of the patients were evaluated, and S. enterica isolates were characterized with regard to serovar, phage type, antimicrobial resistance (phenotype/responsible genes, plasmid content, pulsed-field gel electrophoresis, and multilocus sequence typing. Results: Fifteen S. Typhimurium and 21 S. Enteritidis isolates were recovered from blood samples of 25 children, the majority with underlying risk factors. With regard to phage typing, most isolates were either untypeable or reacted but did not conform, revealing that a number of previously unrecognized patterns are circulating in Mozambique. Most isolates were multidrug-resistant, with nearly all of the responsible genes located on derivatives of serovar-specific virulence plasmids. ST313 and ST11 were the predominant sequence types associated with S. Typhimurium and S. Enteritidis, respectively, and the uncommon ST1479 was also detected in S. Enteritidis. A distinct XbaI fragment of ~350 kb was associated with pulsed-field gel electrophoresis patterns of

  4. Outbreak of Salmonella typhimurium infection traced to contaminated chocolate and caused by a strain lacking the 60-megadalton virulence plasmid.

    OpenAIRE

    Kapperud, G; Gustavsen, S; Hellesnes, I; Hansen, A. H.; Lassen, J; Hirn, J.; Jahkola, M; Montenegro, M A; Helmuth, R

    1990-01-01

    We describe an outbreak of Salmonella typhimurium infection, caused by contaminated chocolate produced by one Norwegian company, which occurred in Norway and Finland in 1987. A total of 349 bacteriologically verified cases were recorded in Norway, and 12 cases were recorded in Finland. There was a predominance of young children among the patients (median age, 6 years), many of whom developed acute hemorrhagic diarrhea. The outbreak strain exhibited a rare phage lysis pattern and a characteris...

  5. Aptasensors for quantitative detection of Salmonella Typhimurium.

    Science.gov (United States)

    Ansari, Najmeh; Yazdian-Robati, Rezvan; Shahdordizadeh, Mahin; Wang, Zhouping; Ghazvini, Kiarash

    2017-09-15

    Salmonella is one of the most frequent causes of food borne infectious disease. Among nearly 2500 documented serotypes are reported, Salmonella Typhimurium is the number one serotype associated with salmonellosis worldwide. Many different methods have been developed for the detection and quantification of S. typhimurium. Most of these assays are usually expensive, time consuming and require difficult sample preparation steps. Therefore, it is necessary to develop rapid, robust, cost-effective and sensitive alternative detection methods. In the last years, aptasensors, used for detection of S. typhimurium in different samples. In this review, recent advances and applications of aptasensors for the detection and quantification of S. typhimurium in details have been summarized. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Outbreak of Salmonella typhimurium infection traced to contaminated chocolate and caused by a strain lacking the 60-megadalton virulence plasmid.

    Science.gov (United States)

    Kapperud, G; Gustavsen, S; Hellesnes, I; Hansen, A H; Lassen, J; Hirn, J; Jahkola, M; Montenegro, M A; Helmuth, R

    1990-12-01

    We describe an outbreak of Salmonella typhimurium infection, caused by contaminated chocolate produced by one Norwegian company, which occurred in Norway and Finland in 1987. A total of 349 bacteriologically verified cases were recorded in Norway, and 12 cases were recorded in Finland. There was a predominance of young children among the patients (median age, 6 years), many of whom developed acute hemorrhagic diarrhea. The outbreak strain exhibited a rare phage lysis pattern and a characteristic plasmid profile lacking the 60-MDa virulence-associated plasmid. DNA hybridization failed to demonstrate any DNA sequence homology between the outbreak strain and the virulence plasmid. The outbreak strain was nonlethal for orally infected mice. The finding of only less than or equal to 10 S. typhimurium cells per 100 g of chocolate in about 90% of the positive samples obtained from retail outlets suggested that an inoculum of fewer than 10 organisms may have been sufficient to cause symptomatic disease.

  7. 9 CFR 113.120 - Salmonella Typhimurium Bacterin.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Salmonella Typhimurium Bacterin. 113... REQUIREMENTS Inactivated Bacterial Products § 113.120 Salmonella Typhimurium Bacterin. Salmonella Typhimurium Bacterin shall be prepared from a culture of Salmonella typhimurium which has been inactivated and is...

  8. Prevalence, antibiogram, molecular characterization and reduction trial of Salmonella typhimurium isolated from different fish species

    OpenAIRE

    Bayomi, Rasha M. El; Darwish, Wageh S.; El-Moaty, Amany M. Abd; Gad, Tamer M.

    2016-01-01

    Salmonella is a major cause of food-borne outbreaks and infections in many countries worldwide. The present work aimed to investigate the prevalence, antibiotic sensitivity and detection of virulence-associated genes in Salmonella typhimurium isolated from fish samples (tilapia, mullet and catfish) collected from Zagazig city markets, Egypt. Salmonella typhimurium was isolated only from tilapia with a percentage of 13.3%. Antibiotic susceptibility testing of Salmonella typhimurium revealed ma...

  9. Epidemic multiple drug resistant Salmonella Typhimurium causing invasive disease in sub-Saharan Africa have a distinct genotype.

    Science.gov (United States)

    Kingsley, Robert A; Msefula, Chisomo L; Thomson, Nicholas R; Kariuki, Samuel; Holt, Kathryn E; Gordon, Melita A; Harris, David; Clarke, Louise; Whitehead, Sally; Sangal, Vartul; Marsh, Kevin; Achtman, Mark; Molyneux, Malcolm E; Cormican, Martin; Parkhill, Julian; MacLennan, Calman A; Heyderman, Robert S; Dougan, Gordon

    2009-12-01

    Whereas most nontyphoidal Salmonella (NTS) are associated with gastroenteritis, there has been a dramatic increase in reports of NTS-associated invasive disease in sub-Saharan Africa. Salmonella enterica serovar Typhimurium isolates are responsible for a significant proportion of the reported invasive NTS in this region. Multilocus sequence analysis of invasive S. Typhimurium from Malawi and Kenya identified a dominant type, designated ST313, which currently is rarely reported outside of Africa. Whole-genome sequencing of a multiple drug resistant (MDR) ST313 NTS isolate, D23580, identified a distinct prophage repertoire and a composite genetic element encoding MDR genes located on a virulence-associated plasmid. Further, there was evidence of genome degradation, including pseudogene formation and chromosomal deletions, when compared with other S. Typhimurium genome sequences. Some of this genome degradation involved genes previously implicated in virulence of S. Typhimurium or genes for which the orthologs in S. Typhi are either pseudogenes or are absent. Genome analysis of other epidemic ST313 isolates from Malawi and Kenya provided evidence for microevolution and clonal replacement in the field.

  10. Sublethal amounts of Origanum vulgare L. essential oil and carvacrol cause injury and changes in membrane fatty acid of Salmonella Typhimurium cultivated in a meat broth.

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    Luz, Isabelle da Silva; de Melo, Adma Nadja Ferreira; Bezerra, Taliana Kênia Alves; Madruga, Marta Suely; Magnani, Marciane; de Souza, Evandro Leite

    2014-05-01

    This study aimed to evaluate whether sublethal concentrations of the essential oil of Origanum vulgare L. (OVEO) and its major compound carvacrol (CAR) cause injury to the cell membrane and outer membrane of Salmonella enterica serovar Typhimurium ATCC 14028 grown in a meat broth and to assess the effect of these substances on membrane fatty acid (FA) composition. Exposure of Salmonella Typhimurium ATCC 14028 to sublethal concentrations of OVEO or CAR caused damage to the cytoplasmic membrane and outer membrane. OVEO- and CAR-treated cells showed lower amounts of saturated FA than nontreated cells. Changes in membrane FA composition were mainly related to an increase of C16:1ω7c, C16:1ω7t, and C18:2ω6c, and to a decrease of C16:0, C17:0 cyclo, and C19:0 cyclo. These results indicate that exposure to sublethal concentrations of OVEO or CAR caused sublethal injury Salmonella Typhimurium ATCC 14028 and suggest that an adaptive response to these stresses is related to increased synthesis of unsaturated FA and cis-trans isomerization.

  11. The effect on the virulence and infectivity of Salmonella typhimurium and Salmonella gallinarum of acquiring antibiotic resistance plasmids from organisms that had caused serious outbreaks of disease.

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    Smith, H W; Tucker, J F

    1979-10-01

    Antibiotic resistance plasmids from organisms that had caused serious epidemics, including those responsible for epidemics of chloramphenicol-resistant typhoid fever and dysentery in Central America, were transferred to a strain of Salmonella typhimurium and of Salmonella gallinarum. The virulence and infectivity of these R(+) forms were then compared with the R(-) parent forms in orally inoculated chickens.None of the R(+) forms were more virulent than their R(-) parent forms. The mortality rates they produced were either the same as or less than that of their R(-) parent forms. The mortality rates were not increased by feeding the chickens on diets containing antibiotics against which the plasmids provided resistance.The removal of the plasmids from some R(+) forms of decreased virulence was not accompanied by any alteration in virulence, indicating that they were less virulent mutants of the parent strain that had conjugated preferentially. In other cases their virulence was increased, indicating that the very possession of the plasmid was involved in their decreased virulence. Of four forms of the S. gallinarum strain harbouring the plasmid that had been incriminated in the Central American dysentery outbreak, one was as virulent as the parent R(-) form and the other three were less virulent. Preferential conjugation by an avirulent mutant was responsible for the lack of virulence of one of them but the very possession of the plasmid appeared responsible for the decreased virulence of the other two. The decreased virulence of de-repressed F(+) and I(+) forms of the S. typhimurium strain was increased to that of repressed F(+) form and of the parent form by plasmid removal.Organisms of the R(+) forms of the S. typhimurium strain were not excreted in larger amounts or for longer periods of time by infected chickens than organisms of the R(-) parent form were. Neither did organisms of the R(+) forms of this strain or the S. gallinarum strain spread more rapidly or

  12. Poor biofilm-forming ability and long-term survival of invasive Salmonella Typhimurium ST313.

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    Ramachandran, Girish; Aheto, Komi; Shirtliff, Mark E; Tennant, Sharon M

    2016-07-01

    Salmonella enterica serovar Typhimurium, an enteric pathogen that causes a self-limiting gastroenteritis, forms biofilms on different surfaces. In sub-Saharan Africa, Salmonella Typhimurium of a novel sequence type (ST) 313 was identified and produces septicemia in the absence of gastroenteritis. No animal reservoir has been identified, and it is hypothesized that transmission occurs via human to human. In this study, we show that invasive Salmonella Typhimurium ST313 strains from Mali are poor biofilm producers compared to Salmonella Typhimurium ST19 strains, which are found worldwide and are known to be associated with gastroenteritis. We evaluated biofilms using crystal violet staining, examination of the red, dry and rough morphotype, pellicle formation and a continuous flow system. One month-old Salmonella Typhimurium ST19 colonies survived in the absence of exogenous nutrients and were highly resistant to sodium hypochlorite treatment compared to Salmonella Typhimurium ST313. This study for the first time demonstrates the comparative biofilm-forming ability and long-term survival of clinical Salmonella Typhimurium ST19 and ST313 isolates. Salmonella Typhimurium ST19 strains are strong biofilm producers and can survive desiccation compared to Salmonella Typhimurium ST313 that form weak biofilms and survive poorly following desiccation. Our data suggest that like Salmonella Typhi, Salmonella Typhimurium ST313 lack mechanisms that allow it to persist in the environment. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Comparison of epidemiological marker methods for identification of Salmonella typhimurium isolates from an outbreak caused by contaminated chocolate.

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    Kapperud, G; Lassen, J; Dommarsnes, K; Kristiansen, B E; Caugant, D A; Ask, E; Jahkola, M

    1989-09-01

    Plasmid profile analysis, restriction endonuclease analysis, and multilocus enzyme electrophoresis were used in conjunction with serotyping, bacteriophage typing, and biochemical fingerprinting to trace epidemiologically related isolates of Salmonella typhimurium from an outbreak caused by contaminated chocolate products in Norway and Finland. To evaluate the efficiency of the epidemiological marker methods, isolates from the outbreak were compared with five groups of control isolates not known to be associated with the outbreak. Both plasmid profile analysis and phage typing provided further discrimination over that produced by serotyping and biochemical fingerprinting. Plasmid profile analysis and phage typing were equally reliable in differentiating the outbreak isolates from the epidemiologically unrelated controls and were significantly more effective than multilocus enzyme electrophoresis and restriction enzyme analysis of total DNA. The greatest differentiation was achieved when plasmid profile analysis and phage typing were combined to complement serotyping and biochemical fingerprinting. However, none of the methods employed, including restriction enzyme analysis of plasmid DNA, were able to distinguish the outbreak isolates from five isolates recovered in Norway and Finland over a period of years from dead passerine birds and a calf.

  14. Anti-Diarrheal Effects of a Combination of Korean Traditional Herbal Extracts and Dioctahedral Smectite on Piglet Diarrhea Caused by Escherichia coli and Salmonella typhimurium

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    Won-Chul Jung§, Chun-Nam Cha§1, Yeo-Eun Lee2, Chang-Yeol Yoo2, 3, Eun-Kee Park4, Suk Kim and Hu-Jang Lee*

    2011-10-01

    Full Text Available The present study evaluated anti-diarrheal effects of a mixture of Coptidis rhizoma, Lonicerae flos, and Paeonia japonica (1:1:1, v/v/v methanol extracts and dioctahedral smectite (CLPD on piglet diarrhea caused by Escherichia coli (E. coli and Salmonella typhimurium (S. typhimurium. Diarrhea index of group 1 administered by 0.5% CLPD mixed with feed, decreased with the passage of time and was insignificantly differed compared to that of control. In group 2 administered by 1.0% CLPD mixed with feed, diarrhea index was significantly decreased compared to that of control and group I during overall experimental periods (P<0.05. After administration of CLPD mixed with feed, the number of E. coli and S. typhimurium in piglet feces of group 1 except for the 1st day was significantly decreased compared to that of the control group (P<0.05, and the number of E. coli and S. typhimurium in piglet feces of group 2 except for the 1st day was significantly decreased compared to that of the control group and group I (P<0.05. This study showed that CLPD had anti-diarrheal effect on E. coli and S. typhimurium causing diarrhea in piglets. CLPD could be an effective candidate for the treatment of enteric bacterial infections in piglets.

  15. Salmonella Typhimurium infection in the porcine intestine

    DEFF Research Database (Denmark)

    Schauser, Kirsten; Olsen, John Elmerdahl; Larsson, Lars-Inge

    2005-01-01

    The normal intestinal epithelium is renewed with a turnover rate of 3-5 days. During Salmonella infection increased cell loss is observed, possibly as a result of programmed cell death (PCD). We have, therefore, studied the effects of Salmonella Typhimurium infection on three elements involved...... in scattered epithelial cells and the number of positive cells increased with increasing times of exposure to Salmonella (P

  16. Experimental Salmonella typhimurium infections in rats. I

    DEFF Research Database (Denmark)

    Hougen, H P; Jensen, E T; Klausen, B

    1989-01-01

    The course of experimentally induced Salmonella typhimurium infection was studied in three groups of inbred LEW rats: homozygous +/+, athymic rnu/rnu and isogeneic thymus-grafted rnu/rnu rats. In the first experiment the animals were inoculated intraperitoneally with 10(8) bacteria and all animals...

  17. Interaction of Salmonella typhimurium and Salmonella enteritidis ...

    African Journals Online (AJOL)

    GRACE

    2006-06-02

    Jun 2, 2006 ... significantly less biofilm on polystyrene when cultured in a starvation medium for 24 h. Adherence to polystyrene. An insignificant difference was observed between S. typhimurium and S. enteritidis in their extent of adherence to polystyrene (Figure 7). Chick mortality and oral median lethal dose (LD50).

  18. Interaction of Salmonella typhimurium and Salmonella enteritidis ...

    African Journals Online (AJOL)

    Biofilms formed by S. enteritidis following growth in sugar-supplemented medium were not significantly different from that following growth in non-supplemented medium; but significant (P <0.05) reduction in amounts of biofilm formed by S. typhimurium were produced by only mannitol (P =0.0008) and xylose (P = 0.00004).

  19. An epidemic of salmonellosis caused by Salmonella Typhimurium DT160 in wild birds and humans in New Zealand.

    Science.gov (United States)

    Alley, M R; Connolly, J H; Fenwick, S G; Mackereth, G F; Leyland, M J; Rogers, L E; Haycock, M; Nicol, C; Reed, C E M

    2002-10-01

    This study reports an outbreak of salmonellosis due to S. Typhimurium DT160 which caused extensive mortality in wild birds and enteric disease in humans in New Zealand during the winter and spring months of the year 2000. Necropsies were performed and microbiological examinations undertaken on wild birds from populations in which mass mortality was reported, and on captive indigenous birds which died suddenly during the winter and spring of 2000. Affected tissues were examined histologically and isolates of S. Typhimurium were phage typed and examined using pulsedfield gel electrophoresis (PFGE). Isolates of S. Typhimurium obtained from cases of human enteric disease which occurred during these months were phage typed, examined using PFGE and compared with the bird isolates. Central and northern areas of the South Island and the southern North Island were worst affected with die-offs of several hundreds of sparrows and other birds reported in rural areas. Mortalities reached a peak in winter (July-August) 2000 and decreased to small numbers during the spring and early summer. The birds usually died of an acute septicaemia with multifocal necrotising lesions in the liver and spleen. Human cases throughout the country increased gradually over the same period. Isolates from birds, livestock and humans examined using PFGE were indistinguishable from one another. This strain of Salmonellahas emerged as a major cause of septicaemia in wild birds in New Zealand. Because of the close association between house sparrows (Passer domesticus) and humans, the organism also poses a serious zoonotic risk. The possibility that the infection may spread to involve indigenous species needs investigation.

  20. Removal of the phage-shock protein PspB causes reduction of virulence in Salmonella enterica serovar Typhimurium independently of NRAMP1

    DEFF Research Database (Denmark)

    Wallrodt, Inke; Jelsbak, Lotte; Thomsen, Line E.

    2014-01-01

    . In Salmonella enterica serovar Typhimurium (S. Typhimurium), it has recently been reported that PspA is essential for systemic infection of mice, but only in NRAMP1(+) mice, signifying that attenuation is related to coping with divalent cation starvation in the intracellular environment. In the present study......IV-induced secretin stress. In conclusion, our results demonstrate that removal of PspB reduces virulence in S. Typhimurium independently of host NRAMP1 expression, demonstrating that PspB has roles in intra-host survival distinct from the reported contributions of PspA....

  1. Isolation of QseC-regulated genes in Salmonella enterica serovar Typhimurium by transposon mutgagenesis

    Science.gov (United States)

    Non-typhoidal Salmonella, a leading cause of U.S. foodborne disease and food-related deaths, often asymptomatically colonizes food-producing animals. In fact, >50% of U.S. swine production facilities test positive for Salmonella. The multidrug-resistant (MDR) Salmonella Typhimurium DT104 NCTC13348 c...

  2. Hydrophobic peptide auxotrophy in Salmonella typhimurium.

    OpenAIRE

    Brãnes, L V; Somers, J M; Kay, W W

    1981-01-01

    The growth of a pleiotropic membrane mutant of Salmonella typhimurium with modified lipopolysaccharide composition was found to be strictly dependent on the peptone component of complex media. Nutritional Shiftdown into minimal media allowed growth for three to four generations. Of 20 commercial peptones, only enzymatic digests supported growth to varying degrees. Neither trace cations, amino acids, vitamins, carbohydrates, lipids, glutathione, polyamines, carbodimides, nor synthetic peptides...

  3. Stress induced Salmonella Typhimurium recrudescence in pigs coincides with cortisol induced increased intracellular proliferation in macrophages

    Science.gov (United States)

    2011-01-01

    Salmonella Typhimurium infections in pigs often result in the development of carriers that intermittently excrete Salmonella in very low numbers. During periods of stress, for example transport to the slaughterhouse, recrudescence of Salmonella may occur, but the mechanism of this stress related recrudescence is poorly understood. Therefore, the aim of the present study was to determine the role of the stress hormone cortisol in Salmonella recrudescence by pigs. We showed that a 24 h feed withdrawal increases the intestinal Salmonella Typhimurium load in pigs, which is correlated with increased serum cortisol levels. A second in vivo trial demonstrated that stress related recrudescence of Salmonella Typhimurium in pigs can be induced by intramuscular injection of dexamethasone. Furthermore, we found that cortisol, but not epinephrine, norepinephrine and dopamine, promotes intracellular proliferation of Salmonella Typhimurium in primary porcine alveolar macrophages, but not in intestinal epithelial cells and a transformed cell line of porcine alveolar macrophages. A microarray based transcriptomic analysis revealed that cortisol did not directly affect the growth or the gene expression or Salmonella Typhimurium in a rich medium, which implies that the enhanced intracellular proliferation of the bacterium is probably caused by an indirect effect through the cell. These results highlight the role of cortisol in the recrudescence of Salmonella Typhimurium by pigs and they provide new evidence for the role of microbial endocrinology in host-pathogen interactions. PMID:22151081

  4. Stress induced Salmonella Typhimurium recrudescence in pigs coincides with cortisol induced increased intracellular proliferation in macrophages

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    Verbrugghe Elin

    2011-12-01

    Full Text Available Abstract Salmonella Typhimurium infections in pigs often result in the development of carriers that intermittently excrete Salmonella in very low numbers. During periods of stress, for example transport to the slaughterhouse, recrudescence of Salmonella may occur, but the mechanism of this stress related recrudescence is poorly understood. Therefore, the aim of the present study was to determine the role of the stress hormone cortisol in Salmonella recrudescence by pigs. We showed that a 24 h feed withdrawal increases the intestinal Salmonella Typhimurium load in pigs, which is correlated with increased serum cortisol levels. A second in vivo trial demonstrated that stress related recrudescence of Salmonella Typhimurium in pigs can be induced by intramuscular injection of dexamethasone. Furthermore, we found that cortisol, but not epinephrine, norepinephrine and dopamine, promotes intracellular proliferation of Salmonella Typhimurium in primary porcine alveolar macrophages, but not in intestinal epithelial cells and a transformed cell line of porcine alveolar macrophages. A microarray based transcriptomic analysis revealed that cortisol did not directly affect the growth or the gene expression or Salmonella Typhimurium in a rich medium, which implies that the enhanced intracellular proliferation of the bacterium is probably caused by an indirect effect through the cell. These results highlight the role of cortisol in the recrudescence of Salmonella Typhimurium by pigs and they provide new evidence for the role of microbial endocrinology in host-pathogen interactions.

  5. Survival of Salmonella east bourne and Salmonella typhimurium in chocolate.

    Science.gov (United States)

    Tamminga, S K; Beumer, R R; Kampelmacher, E H; van Leusden, F M

    1976-02-01

    Experiments were carried out to assess the reduction rate of two salmonella strains (S. eastbourne and S. typhimurium) in chocolate bars. After artificial contamination of chocolate, after 'conching', with about 10(6) S. eastbourne/g. this organism was still recovered after 9 months storage. The strain of S. typhimurium was less resistant. Both serotypes died off more rapidly in bitter chocolate than in milk chocolate. After contamination with a smaller dose (about 10(3)/g.) with these two serotypes, similar differences were observed.

  6. Immune reaction and survivability of salmonella typhimurium and salmonella infantis after infection of primary avian macrophages.

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    Maria Braukmann

    Full Text Available Salmonella serovars are differentially able to infect chickens. The underlying causes are not yet fully understood. Aim of the present study was to elucidate the importance of Salmonella Pathogenicity Island 1 and 2 (SPI-1 and -2 for the virulence of two non-host-specific, but in-vivo differently invasive, Salmonella serovars in conjunction with the immune reaction of the host. Primary avian splenic macrophages were inoculated with Salmonella enterica sub-species enterica serovar (S. Typhimurium and S. Infantis. The number and viability of intracellular bacteria and transcription of SPI-1 and -2 genes by the pathogens, as well as transcription of immune-related proteins, surface antigen expression and nitric oxide production by the macrophages, were compared at different times post inoculation. After infection, both of the Salmonella serovars were found inside the primary macrophages. Invasion-associated SPI-1 genes were significantly higher transcribed in S. Infantis- than S. Typhimurium-infected macrophages. The macrophages counteracted the S. Infantis and S. Typhimurium infection with elevated mRNA expression of inducible nitric oxide synthase (iNOS, interleukin (IL-12, IL-18 and lipopolysaccharide-induced tumor necrosis factor alpha factor (LITAF as well as with an increased synthesis of nitric oxide. Despite these host cell attacks, S. Typhimurium was better able than S. Infantis to survive within the macrophages and transcribed higher rates of the SPI-2 genes spiC, ssaV, sifA, and sseA. The results showed similar immune reactions of primary macrophages after infection with both of the Salmonella strains. The more rapid and stronger transcription of SPI-2-related genes by intracellular S. Typhimurium compared to S. Infantis might be responsible for its better survival in avian primary macrophages.

  7. Intracontinental spread of human invasive Salmonella Typhimurium pathovariants in sub-Saharan Africa.

    Science.gov (United States)

    Okoro, Chinyere K; Kingsley, Robert A; Connor, Thomas R; Harris, Simon R; Parry, Christopher M; Al-Mashhadani, Manar N; Kariuki, Samuel; Msefula, Chisomo L; Gordon, Melita A; de Pinna, Elizabeth; Wain, John; Heyderman, Robert S; Obaro, Stephen; Alonso, Pedro L; Mandomando, Inacio; MacLennan, Calman A; Tapia, Milagritos D; Levine, Myron M; Tennant, Sharon M; Parkhill, Julian; Dougan, Gordon

    2012-11-01

    A highly invasive form of non-typhoidal Salmonella (iNTS) disease has recently been documented in many countries in sub-Saharan Africa. The most common Salmonella enterica serovar causing this disease is Typhimurium (Salmonella Typhimurium). We applied whole-genome sequence-based phylogenetic methods to define the population structure of sub-Saharan African invasive Salmonella Typhimurium isolates and compared these to global Salmonella Typhimurium populations. Notably, the vast majority of sub-Saharan invasive Salmonella Typhimurium isolates fell within two closely related, highly clustered phylogenetic lineages that we estimate emerged independently ∼52 and ∼35 years ago in close temporal association with the current HIV pandemic. Clonal replacement of isolates from lineage I by those from lineage II was potentially influenced by the use of chloramphenicol for the treatment of iNTS disease. Our analysis suggests that iNTS disease is in part an epidemic in sub-Saharan Africa caused by highly related Salmonella Typhimurium lineages that may have occupied new niches associated with a compromised human population and antibiotic treatment.

  8. A Descriptive Study of Human Salmonella Serotype Typhimurium Infections Reported in Ontario from 1990 to 1997

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    Michael W Ford

    2003-01-01

    Full Text Available BACKGROUND: Salmonella infections cause gastrointestinal and systemic diseases worldwide and are the leading causes of food-borne illnesses in North America (1-4. Salmonella serotype typhimurium (ST, in particular, is increasingly becoming a major public health concern because of its ability to acquire multiple resistant genes (5,6.

  9. Study of Salmonella Typhimurium Infection in Laying Hens

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    Pande, Vivek V.; Devon, Rebecca L.; Sharma, Pardeep; McWhorter, Andrea R.; Chousalkar, Kapil K.

    2016-01-01

    Members of Salmonella enterica are frequently involved in egg and egg product related human food poisoning outbreaks worldwide. In Australia, Salmonella Typhimurium is frequently involved in egg and egg product related foodborne illness and Salmonella Mbandaka has also been found to be a contaminant of the layer farm environment. The ability possessed by Salmonella Enteritidis to colonize reproductive organs and contaminate developing eggs has been well-described. However, there are few studies investigating this ability for Salmonella Typhimurium. The hypothesis of this study was that the Salmonella Typhimurium can colonize the gut for a prolonged period of time and that horizontal infection through feces is the main route of egg contamination. At 14 weeks of age hens were orally infected with either S. Typhimurium PT 9 or S. Typhimurium PT 9 and Salmonella Mbandaka. Salmonella shedding in feces and eggs was monitored for 15 weeks post-infection. Egg shell surface and internal contents of eggs laid by infected hens were cultured independently for detection of Salmonella spp. The mean Salmonella load in feces ranged from 1.54 to 63.35 and 0.31 to 98.38 most probable number/g (MPN/g) in the S. Typhimurium and S. Typhimurium + S. Mbandaka group, respectively. No correlation was found between mean fecal Salmonella load and frequency of egg shell contamination. Egg shell contamination was higher in S. Typhimurium + S. Mbandaka infected group (7.2% S. Typhimurium, 14.1% S. Mbandaka) compared to birds infected with S. Typhimurium (5.66%) however, co-infection had no significant impact on egg contamination by S. Typhimurium. Throughout the study Salmonella was not recovered from internal contents of eggs laid by hens. Salmonella was isolated from different segments of oviduct of hens from both the groups, however pathology was not observed on microscopic examination. This study investigated Salmonella shedding for up to 15 weeks p.i which is a longer period of time

  10. Factors affecting the excretion of GFP Salmonella enterica serovar typhimurium by adult house flies (Diptera: Muscidae; Musca domestica L.)

    Science.gov (United States)

    House flies harbor and disseminate food-borne pathogens. Salmonella Typhimurium (S. Typhimurium) is a zoonotic pathogen shed by livestock that causes gastroenteritis in humans. We previously demonstrated that GFP-S. Typhimurium fed to house flies persist in the digestive for 24h. The excretion dynam...

  11. Study of Salmonella Typhimurium infection in laying hens

    Directory of Open Access Journals (Sweden)

    Kapil eChousalkar

    2016-02-01

    Full Text Available Members of Salmonella enterica are frequently involved in egg and egg product related human food poisoning outbreaks worldwide. In Australia, Salmonella Typhimurium is frequently involved in egg and egg product related foodborne illness and Salmonella Mbandaka has also been found to be a contaminant of the layer farm environment. The ability possessed by Salmonella Enteritidis to colonise reproductive organs and contaminate developing eggs has been well described. However, there are few studies investigating this ability for Salmonella Typhimurium. The hypothesis of this study was that the Salmonella Typhimurium can colonise the gut for a prolonged period of time and that horizontal infection through feces is the main route of egg contamination. At 14 weeks of age hens were orally infected with either S. Typhimurium PT 9 or S. Typhimurium PT 9 and Salmonella Mbandaka. Salmonella shedding in feces and eggs was monitored for 15 weeks post infection. Egg shell surface and internal contents of eggs laid by infected hens were cultured independently for detection of Salmonella spp. The mean Salmonella load in feces ranged from 1.54 to 63.35 and 0.31 to 98.38 most probable number/g (MPN/g in the S. Typhimurium and S. Typhimurium + S. Mbandaka group respectively. No correlation was found between mean fecal Salmonella load and frequency of egg shell contamination. Egg shell contamination was higher in S. Typhimurium + S. Mbandaka infected group (7.2% Typhimurium, 14.1% Mbandaka compared to birds infected with S. Typhimurium (5.66% however, co-infection had no significant impact on egg contamination by S. Typhimurium. Throughout the study Salmonella was not recovered from internal contents of eggs laid by hens. Salmonella was isolated from different segments of oviduct of hens from both the groups, however pathology was not observed on microscopic examination. This study investigated Salmonella shedding for up to 15 weeks p.i which is a longer period of

  12. Studies on the pathogenesis of Salmonella typhimurium and Salmonella choleraesuis var kunzendorf infection in weanling pigs.

    Science.gov (United States)

    Reed, W M; Olander, H J; Thacker, H L

    1986-01-01

    Twenty-six 4-week-old pigs were randomly allotted to 4 groups: group 1--orally inoculated with Salmonella typhimurium; group 2--orally dosed with S choleraesuis; and groups 3 and 4, with surgically constructed intestinal loops--loops inoculated with either S typhimurium or S choleraesuis. One pig each from groups 1 and 2 was killed at 8, 12, 24, 48, 72, 96, and 120 hours after inoculation. One pig each from groups 3 and 4 was killed at 2, 4, 6, 8, 12, and 24 hours after intestinal loop inoculation. Inoculation of S typhimurium resulted in acute enterocolitis of variable severity, whereas inoculation of S choleraesuis resulted initially in septicemia followed by formation of large necrotic and ulcerative lesions in the colonic mucosa. The most consistent systemic lesion of S choleraesuis infection was interstitial pneumonia and multifocal hepatic necrosis. Salmonella typhimurium and S choleraesuis were ultrastructurally within enterocytes of ligated ileal loops. Intracellular bacteria were morphologically intact, occurred free in the cytoplasm and membrane bound, and caused no detectable cytotoxic effect to the cell. Both S typhimurium and S choleraesuis penetrated the intestinal mucosa and were isolated from mesenteric lymph nodes at 2 hours after inoculation.

  13. Recognition of nomenclatural standing of Salmonella typhi (Approved Lists 1980), Salmonella enteritidis (Approved Lists 1980) and Salmonella typhimurium (Approved Lists 1980), and conservation of the specific epithets enteritidis and typhimurium. Request for an opinion.

    Science.gov (United States)

    Ezaki, T; Kawamura, Y; Yabuuchi, E

    2000-03-01

    In 1994, the Judicial Commission of the ICSB announced that Le Minor and Popoff's Request for an Opinion in 1987 to designate Salmonella enterica sp. nov., nom. rev. as the type and only species of the genus Salmonella was denied. Thus, the current species of the genus Salmonella are Salmonella typhimurium, Salmonella enteritidis, Salmonella typhi, Salmonella choleraesuis (including six subspecies) and Salmonella bongori, with the type species, S. choleraesuis (Smith 1894) Weldin 1927 (Approved Lists 1980). Because the decision of the Judicial Commission about the request by Le Minor in 1987 was suspended for 7 years, the non-validated name 'S. enterica' has been used among microbiologists and has caused confusion in the nomenclature of Salmonella. In order to overcome such confusion, and because of their importance as human pathogens, we herein propose to recognize the nomenclatural status of S. typhi, S. enteritidis and S. typhimurium as species and request to issue an Opinion to conserve the specific epithets enteritidis and typhimurium in the species names Salmonella enteritidis and Salmonella typhimurium.

  14. T-2 toxin induced Salmonella Typhimurium intoxication results in decreased Salmonella numbers in the cecum contents of pigs, despite marked effects on Salmonella-host cell interactions

    Science.gov (United States)

    2012-01-01

    The mycotoxin T-2 toxin and Salmonella Typhimurium infections pose a significant threat to human and animal health. Interactions between both agents may result in a different outcome of the infection. Therefore, the aim of the presented study was to investigate the effects of low and relevant concentrations of T-2 toxin on the course of a Salmonella Typhimurium infection in pigs. We showed that the presence of 15 and 83 μg T-2 toxin per kg feed significantly decreased the amount of Salmonella Typhimurium bacteria present in the cecum contents, and a tendency to a reduced colonization of the jejunum, ileum, cecum, colon and colon contents was noticed. In vitro, proteomic analysis of porcine enterocytes revealed that a very low concentration of T-2 toxin (5 ng/mL) affects the protein expression of mitochondrial, endoplasmatic reticulum and cytoskeleton associated proteins, proteins involved in protein synthesis and folding, RNA synthesis, mitogen-activated protein kinase signaling and regulatory processes. Similarly low concentrations (1-100 ng/mL) promoted the susceptibility of porcine macrophages and intestinal epithelial cells to Salmonella Typhimurium invasion, in a SPI-1 independent manner. Furthermore, T-2 toxin (1-5 ng/mL) promoted the translocation of Salmonella Typhimurium over an intestinal porcine epithelial cell monolayer. Although these findings may seem in favour of Salmonella Typhimurium, microarray analysis showed that T-2 toxin (5 ng/mL) causes an intoxication of Salmonella Typhimurium, represented by a reduced motility and a downregulation of metabolic and Salmonella Pathogenicity Island 1 genes. This study demonstrates marked interactions of T-2 toxin with Salmonella Typhimurium pathogenesis, resulting in bacterial intoxication. PMID:22440148

  15. Salmonella typhimurium phage typing for pathogens.

    Science.gov (United States)

    Rabsch, Wolfgang

    2007-01-01

    Phage typing provides a rapid, accurate, and cheap method of investigating Salmonella strains for epidemiological use. Salmonella strains within a particular serovar may be differentiated into a number of phage types by their pattern of susceptibility to lysis by a set of phages with different specificity. Characterization based on the pattern of phage lysis of wild strains isolated from different patients, carriers, or other sources is valuable in epidemiological study. The phages must have well-defined propagation strains that allow reproducible discrimination between different Salmonella Typhimurium strains. Different schemes have been developed for this serovar in different countries. The Felix/Callow (England) and Lilleengen typing systems (Sweden) used for laboratory-based epidemiological analysis were helpful for control of salmonellosis. More recently, the extended phage-typing system of Anderson (England) that distinguishes more than 300 definitive phage types (DTs) has been used worldwide in Europe, the United States, and Australia. The use of this method for decades show us that some phage types (DT204 in the 1970s and DT104 in the 1990s) have a broad host range and are distributed worldwide, other phage types such as DT2 or DT99 are frequently associated with disease in pigeons, indicative of a narrow host range.

  16. Study of Salmonella typhimurium mutagenicity assay of (E ...

    African Journals Online (AJOL)

    Study of Salmonella typhimurium mutagenicity assay of (E)-piplartine by the Ames test. AA Morandim-Giannetti, F Cotinguiba, LO Regasini, MC Frigieri, EA Varanda, A Coqueiro, MJ Kato, VS Bolzani, M Furlan ...

  17. Salmonella typhimurium Infection Reduces Schistosoma japonicum Worm Burden in Mice

    OpenAIRE

    Xiaoyang Zhu; Lu Chen; Junfang Wu; Huiru Tang; Yulan Wang

    2017-01-01

    Coinfection of microorganisms is a common phenomenon in humans and animals. In order to further our understanding of the progress of coinfection and the possible interaction between different pathogens, we have built a coinfection mouse model with Schistosoma japonicum and Salmonella typhimurium, and used this model to investigate the systemic metabolic and immune responses using NMR-based metabonomics and immunological techniques. Our results show that Salmonella typhimurium (ATCC14028) infe...

  18. Intra-continental spread of human invasive Salmonella Typhimurium pathovariants in sub-Saharan Africa

    Science.gov (United States)

    Okoro, Chinyere K.; Kingsley, Robert A.; Connor, Thomas R.; Harris, Simon R.; Parry, Christopher M.; Al-Mashhadani, Manar N; Kariuki, Samuel; Msefula, Chisomo L.; Gordon, Melita A.; de Pinna, Elizabeth; Wain, John; Heyderman, Robert S.; Obaro, Stephen; Alonso, Pedro L.; Mandomando, Inacio; MacLennan, Calman A.; Tapia, Milagritos D.; Levine, Myron M.; Tennant, Sharon M; Parkhill, Julian; Dougan, Gordon

    2012-01-01

    A highly invasive form of non-typhoidal Salmonella (iNTS) disease has been recently documented in many countries in sub-Saharan Africa. The most common Salmonella enterica serovar causing this disease is Typhimurium. We applied whole-genome sequence-based phylogenetic methods to define the population structure of sub-Saharan African invasive Salmonella Typhimurium and compared these to global Salmonella Typhimurium isolates. Notably, the vast majority of sub-Saharan invasive Salmonella Typhimurium fell within two closely-related, highly-clustered phylogenetic lineages that we estimate emerged independently ~52 and ~35 years ago, in close temporal association with the current HIV pandemic. Clonal replacement of isolates of lineage I by lineage II was potentially influenced by the use of chloramphenicol for the treatment of iNTS disease. Our analysis suggests that iNTS disease is in part an epidemic in sub-Saharan Africa caused by highly related Salmonella Typhimurium lineages that may have occupied new niches associated with a compromised human population and antibiotic treatment. PMID:23023330

  19. Salmonella identification from foods in eight hours: A prototype study with Salmonella Typhimurium.

    Science.gov (United States)

    Koluman, A; Celik, G; Unlu, T

    2012-03-01

    The significant rise in food borne infections is mainly caused by Campylobacter spp., Salmonella serovars and Verotoxigenic Escherichia coli. As the emerging food borne pathogens cause disease, more studies have been conducted for rapid detection of these pathogens. The combination of immunomagnetic separation and polymerase chain reaction (IMS-PCR) is the most accurate and rapid test preferred by almost every researcher. Fourier Transform Infrared Spectroscopy (FTIR) is preferred for being a new, user friendly and rapid technique in microbiological analyses. The main aim of this study is to detect application of IMS-FTIR for Salmonella identification from foods in a short time with a higher sensitivity. Conventional Culture Technique (CC), IMS-CC, IMS-PCR and IMS-FTIR techniques were compared with each other for rapid detection in artificially contaminated minced beef with Salmonella Typhimurium, as of the 2(nd), 4(th) and 8(th) hours of contamination. The method was evaluated in different food matrices and sensitivity, specifity and overall recovery was calculated. The results indicate that IMS-FTIR can detect S. Typhimurium as of the 8(th) hour with sensitivity of 95.6667, accuracy of 91.69329, false positive ratio of 0.04333 and overall recovery of 95.66%. It can be suggested that the IMS-FTIR method is capable of detecting S.Typhimurium in a short time with lower cost.

  20. Detection of Salmonella spp, Salmonella Enteritidis and Typhimurium in naturally infected broiler chickens by a multiplex PCR-based assay

    Directory of Open Access Journals (Sweden)

    F.G. Paião

    2013-01-01

    Full Text Available The presence of Salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible by the introduction of this microorganism in the slaughterhouses. A rapid method to identify and monitor Salmonella and their sorovars in farm is becoming necessary. A pre-enriched multiplex polymerase chain reaction (m-PCR assay employing specific primers was developed and used to detect Salmonella at the genus level and to identify the Salmonella enterica serovar Enteritidis (S. Enteritidis and Salmonella enterica serovar Typhimurium (S. Typhimurium in broiler chicken swab samples. The method was validated by testing DNA extract from 90 fresh culture cloacal swab samples from poultry chicken cultured in phosphate buffer peptone water at 37 ºC for 18 h. The final results showed the presence of Salmonella spp. in 25% of samples, S. Enteritidis was present in 12% of the Salmonella-positive samples and S. Typhimurium in 3% of the samples. The m-PCR assay developed in this study is a specific and rapid alternative method for the identification of Salmonella spp. and allowed the observation of specific serovar contamination in the field conditions within the locations where these chickens are typically raised.

  1. Detection of Salmonella spp, Salmonella Enteritidis and Typhimurium in naturally infected broiler chickens by a multiplex PCR-based assay.

    Science.gov (United States)

    Paião, F G; Arisitides, L G A; Murate, L S; Vilas-Bôas, G T; Vilas-Boas, L A; Shimokomaki, M

    2013-01-01

    The presence of Salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible by the introduction of this microorganism in the slaughterhouses. A rapid method to identify and monitor Salmonella and their sorovars in farm is becoming necessary. A pre-enriched multiplex polymerase chain reaction (m-PCR) assay employing specific primers was developed and used to detect Salmonella at the genus level and to identify the Salmonella enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterica serovar Typhimurium (S. Typhimurium) in broiler chicken swab samples. The method was validated by testing DNA extract from 90 fresh culture cloacal swab samples from poultry chicken cultured in phosphate buffer peptone water at 37 °C for 18 h. The final results showed the presence of Salmonella spp. in 25% of samples, S. Enteritidis was present in 12% of the Salmonella-positive samples and S. Typhimurium in 3% of the samples. The m-PCR assay developed in this study is a specific and rapid alternative method for the identification of Salmonella spp. and allowed the observation of specific serovar contamination in the field conditions within the locations where these chickens are typically raised.

  2. House Sparrows Do Not Constitute a Significant Salmonella Typhimurium Reservoir across Urban Gradients in Flanders, Belgium.

    Directory of Open Access Journals (Sweden)

    Lieze Oscar Rouffaer

    Full Text Available In recent decades major declines in urban house sparrow (Passer domesticus populations have been observed in north-western European cities, whereas suburban and rural house sparrow populations have remained relatively stable or are recovering from previous declines. Differential exposure to avian pathogens known to cause epidemics in house sparrows may in part explain this spatial pattern of declines. Here we investigate the potential effect of urbanization on the development of a bacterial pathogen reservoir in free-ranging house sparrows. This was achieved by comparing the prevalence of Salmonella enterica subspecies enterica serotype Typhimurium in 364 apparently healthy house sparrows captured in urban, suburban and rural regions across Flanders, Belgium between September 2013 and March 2014. In addition 12 dead birds, received from bird rescue centers, were necropsied. The apparent absence of Salmonella Typhimurium in fecal samples of healthy birds, and the identification of only one house sparrow seropositive for Salmonella spp., suggests that during the winter of 2013-2014 these birds did not represent any considerable Salmonella Typhimurium reservoir in Belgium and thus may be considered naïve hosts, susceptible to clinical infection. This susceptibility is demonstrated by the isolation of two different Salmonella Typhimurium strains from two of the deceased house sparrows: one DT99, typically associated with disease in pigeons, and one DT195, previously associated with a passerine decline. The apparent absence (prevalence: <1.3% of a reservoir in healthy house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmonella Typhimurium strains. However, no inference could be made on a causal relationship between Salmonella infection and the observed house sparrow population declines.

  3. House Sparrows Do Not Constitute a Significant Salmonella Typhimurium Reservoir across Urban Gradients in Flanders, Belgium.

    Science.gov (United States)

    Rouffaer, Lieze Oscar; Lens, Luc; Haesendonck, Roel; Teyssier, Aimeric; Hudin, Noraine Salleh; Strubbe, Diederik; Haesebrouck, Freddy; Pasmans, Frank; Martel, An

    2016-01-01

    In recent decades major declines in urban house sparrow (Passer domesticus) populations have been observed in north-western European cities, whereas suburban and rural house sparrow populations have remained relatively stable or are recovering from previous declines. Differential exposure to avian pathogens known to cause epidemics in house sparrows may in part explain this spatial pattern of declines. Here we investigate the potential effect of urbanization on the development of a bacterial pathogen reservoir in free-ranging house sparrows. This was achieved by comparing the prevalence of Salmonella enterica subspecies enterica serotype Typhimurium in 364 apparently healthy house sparrows captured in urban, suburban and rural regions across Flanders, Belgium between September 2013 and March 2014. In addition 12 dead birds, received from bird rescue centers, were necropsied. The apparent absence of Salmonella Typhimurium in fecal samples of healthy birds, and the identification of only one house sparrow seropositive for Salmonella spp., suggests that during the winter of 2013-2014 these birds did not represent any considerable Salmonella Typhimurium reservoir in Belgium and thus may be considered naïve hosts, susceptible to clinical infection. This susceptibility is demonstrated by the isolation of two different Salmonella Typhimurium strains from two of the deceased house sparrows: one DT99, typically associated with disease in pigeons, and one DT195, previously associated with a passerine decline. The apparent absence (prevalence: house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmonella Typhimurium strains. However, no inference could be made on a causal relationship between Salmonella infection and the observed house sparrow population declines.

  4. Multilocus Sequence Typing of the Clinical Isolates of Salmonella Enterica Serovar Typhimurium in Tehran Hospitals

    Directory of Open Access Journals (Sweden)

    Reza Ranjbar

    2017-09-01

    Full Text Available Background: Salmonella enterica serovar Typhimurium is one of the most important serovars of Salmonella enterica and is associated with human salmonellosis worldwide. Many epidemiological studies have focused on the characteristics of Salmonella Typhimurium in many countries as well as in Asia. This study was conducted to investigate the genetic characteristics of Salmonella Typhimurium using multilocus sequence typing (MLST. Methods: Clinical samples (urine, blood, and stool were collected from patients, who were admitted to 2 hospitals in Tehran between April and September, 2015. Salmonella Typhimurium strains were identified by conventional standard biochemical and serological testing. The antibiotic susceptibility patterns of the Salmonella Typhimurium isolates against 16 antibiotics was determined using the disk diffusion assay. The clonal relationship between the strains of Salmonella Typhimurium was analyzed using MLST. Results: Among the 68 Salmonella isolates, 31% (n=21 were Salmonella Typhimurium. Of the total 21 Salmonella Typhimurium isolates, 76% (n=16 were multidrug-resistant and showed resistance to 3 or more antibiotic families. The Salmonella Typhimurium isolates were assigned to 2 sequence types: ST19 and ST328. ST19 was more common (86%. Both sequence types were further assigned to 1 eBURST group. Conclusion: This is the first study of its kind in Iran to determine the sequence types of the clinical isolates of Salmonella Typhimurium in Tehran hospitals using MLST. ST19 was detected as the major sequence type of Salmonella Typhimurium.

  5. Infection of chickens with antimicrobial-resistant Salmonella enterica Typhimurium DT193 and monophasic Salmonella Typhimurium-like variants: an emerging risk to the poultry industry?

    Science.gov (United States)

    Parsons, B N; Crayford, G; Humphrey, T J; Wigley, P

    2013-01-01

    Antimicrobial-resistant Salmonella enterica poses a particular risk to public health, and in particular isolates belonging to clonal lineages such as Salmonella Typhimurium DT104 cause epidemics across species including poultry. In recent years, antimicrobial-resistant S. Typhimurium DT193 and specifically the monophasic S. Typhimurium-like variants of this phage type, serotypes 4,12:i:- and 4,5,12:i:-, have become an increasing risk to public health in Europe and the USA and now account for nearly one-half of human S. Typhimurium infections in the UK. Unlike S. Typhimurium that possesses two forms of flagella which can vary between phase 1 and phase 2 during infection, monophasic variants possess only phase 1 flagella. These monophasic antimicrobial-resistant variants have become a major problem in pig production but human cases have also been associated with poultry consumption and have been found in UK flocks through surveillance schemes since 2010. In this study we determined the ability of antimicrobial-resistant DT193 serotype 4,12:i:- and 4,5,12:i:- isolates from pigs to infect chickens. All isolates were found to colonize the caeca and liver. All but one isolate of serotype 4,5,12:i:- also infected the spleen. Levels of infection and pathology were comparable with those found with the virulent S. Typhimurium isolate 4/74. These findings indicate that both S. Typhimurium DT193 and monophasic variants of this phage type usually associated with pigs are capable of colonizing the chicken. This shows that both S. Typhimurium DT193 and monophasic variants represent a significant and potential emerging threat to poultry production from "spill-over" of these isolates from the pig industry or other sources.

  6. Plasma-treated polyethylene film: A smart material applied for Salmonella Typhimurium detection

    Energy Technology Data Exchange (ETDEWEB)

    Peng-Ubol, Triranat [Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Phinyocheep, Pranee, E-mail: scppo@mahidol.ac.th [Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Daniel, Philippe [Laboratoire de Physique de l' Etat Condense (LPEC-UMR CNRS 6087), Universite du Maine, Avenue Olivier Messiaen, 72085, Le Mans Cedex 9 (France); Panbangred, Watanalai [Department of Biotechnology and Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology (MU-OU: CRC), Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Pilard, Jean-Francois [Unite de Chimie Organique Moleculaire et Macromoleculaire (UCO2M-UMR CNRS 6011), Universite du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Thouand, Gerald; Durand-Thouand, Marie-Jose [Genie des Procedes Environnement et Agroalimentaire (GEPEA UMR CNRS 6144), Departement Genie Biologique, IUT de la Roche/Yon, Universite de Nantes, 18 Bd G. Defferre, 85035 La Roche sur Yon (France)

    2012-12-01

    Salmonella is a major cause of foodborne illness worldwide and is not allowed to be present in any food in all countries. The purpose of this study is to develop a simple alternative method for the detection of Salmonella based on functionalized polyethylene (PE) surfaces. Salmonella Typhimurium was used as a model bacterium. PE film was treated using dielectric plasma in order to alter the wettability of the PE surface and consequently introduce functionality on the surface. The PE film characterized by ATR-FTIR spectroscopy revealed the presence of C=O stretching of ketones, aldehydes and carboxylic acids. The antibodies against O or H antigens of Salmonella and S. Typhimurium were then respectively immobilized on the PE surface after activation of the carboxylic group using NHS/EDC followed by protein A. The evidences from ATR-FTIR, scanning electron microscopy and optical microscopy showed the presence of S. Typhimurium attached to the plasma treated PE surfaces via the two types of anti-Salmonella antibody. The plasma treated PE film developed is simple and allows efficient association of bacterial cells on the treated surfaces without the necessity of time-consuming centrifugation and washing steps for isolation of the cells. This material is considered to be a smart material applicable for S. Typhimurium detection. Highlights: Black-Right-Pointing-Pointer We developed a functionalized polyethylene film for bacterial detection. Black-Right-Pointing-Pointer We modified the surface of polyethylene film by plasma treatment. Black-Right-Pointing-Pointer ATR-FTIR spectroscopy was used to analyze the functionality on the PE surface. Black-Right-Pointing-Pointer We introduced Salmonella Typhimurium on the modified PE film. Black-Right-Pointing-Pointer SEM revealed the presence of S. Typhimurium on the plasma treated PE film.

  7. Label-free SERS detection of Salmonella Typhimurium on DNA aptamer modified AgNR substrates

    Science.gov (United States)

    Salmonella Typhimurium is an important foodborne pathogen which causes gastroenteritis in both humans and animals. Currently available rapid methods have relied on antibodies to offer specific recognition of the pathogen from the background. As a substitute of antibodies, nucleic acid aptamers offer...

  8. Ultraviolet (UV-C) inactivation of Enterococcus faecium, Salmonella choleraesuis and Salmonella typhimurium in porcine plasma

    OpenAIRE

    Bl?zquez, Elena; Rodr?guez, Carmen; R?denas, Jes?s; P?rez de Rozas, Ana; Segal?s, Joaquim; Pujols, Joan; Polo, Javier

    2017-01-01

    The objective of this study was to assess the effectiveness of an ultraviolet (UV-C, 254 nm) irradiation system on reducing the load of Salmonella typhimurium (S. typhimurium), Salmonella choleraesuis (S. choleraesuis) resistant to streptomycin and Enterococcus faecium (E. faecium) inoculated in sterile porcine plasma and then subjected to different UV-C irradiation doses (750, 1500, 3000, 6000 and 9000 J/L) using a pilot plant UV-C device working under turbulent flow. Results indicated that ...

  9. Immunogenic potential of a Salmonella Typhimurium live vaccine for pigs against monophasic Salmonella Typhimurium DT 193.

    Science.gov (United States)

    Theuß, Tobias; Ueberham, Elke; Lehmann, Jörg; Lindner, Thomas; Springer, Sven

    2017-11-17

    Monophasic Salmonella Typhimurium (mSTM) strains account for up to 8.6% of all human Salmonellosis cases. They have an increasing prevalence during recent years and several human cases with hospitalisation were reported. These strains are often isolated from pigs and pork - one primary source of human infection. A Salmonella Typhimurium (STM) live vaccine has been proven successful in controlling of STM infections in pigs for many years. The aim of this study was to test the immunogenicity of the vaccine in weaners during oral challenge with a virulent mSTM strain and to examine the kinetics of STM-specific IgA, IgM and IgG antibodies induced by vaccination and infection. Despite clinical signs being present in both groups, the vaccination led to a significant reduction of diarrhoea, overall clinical symptoms and a milder elevation of the body temperature. Necropsy revealed fewer pathological lesions in the gastrointestinal tract of vaccinated compared to control animals. Moreover, in the ileal and caecal mucosa and in the ileocaecal lymph nodes the challenge strain burden was significantly reduced by vaccination. Significant differences in the antibody responses of both groups were present during the vaccination period and after infection. In vaccinated animals Salmonella-specific IgA and IgG antibody levels increased significantly after vaccination and were even more pronounced in response to challenge. In contrast, similarly low levels of IgM antibodies were detected during the vaccination period in both vaccinated and non-vaccinated animals. However, after challenge IgM antibody levels increased significantly in control pigs while neither IgA nor IgG antibodies were detectable. The data demonstrate that mSTM can evoke clinical signs in weaners. Due to the vaccination their incidence and magnitude were significantly milder. Vaccination also led to a significantly reduced challenge strain burden in the intestine and the lymph nodes which is comparable to previous

  10. O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections.

    Science.gov (United States)

    Li, Pei; Liu, Qing; Luo, Hongyan; Liang, Kang; Yi, Jie; Luo, Ying; Hu, Yunlong; Han, Yue; Kong, Qingke

    2017-01-01

    Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1, and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S. Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S. Typhimurium was converted into O9, O7, and O8 serotypes through unmarked chromosomal deletion-insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion mutations were successfully introduced into the live attenuated S. Typhimurium vaccine S738 (Δcrp Δcya) to evaluate their immunogenicity in mice model. The vaccine candidates induced high amounts of heterologous O-polysaccharide-specific functional IgG responses. Vaccinated mice survived a challenge of 100 times the 50% lethality dose (LD50) of wild-type S. Typhimurium. Protective efficacy against heterologous virulent Salmonella challenges was highly O-serotype related. Furthermore, broad-spectrum protection against S. Typhimurium, S. Enteritidis, and S. Choleraesuis was observed by co-vaccination of O9 and O7 O-serotype-converted vaccine candidates. This study highlights the strategy of expressing heterologous O-polysaccharides via genetic engineering in developing live attenuated S. Typhimurium vaccines against NTS infections.

  11. O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections

    Directory of Open Access Journals (Sweden)

    Pei Li

    2017-12-01

    Full Text Available Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1, and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S. Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S. Typhimurium was converted into O9, O7, and O8 serotypes through unmarked chromosomal deletion–insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion mutations were successfully introduced into the live attenuated S. Typhimurium vaccine S738 (Δcrp Δcya to evaluate their immunogenicity in mice model. The vaccine candidates induced high amounts of heterologous O-polysaccharide-specific functional IgG responses. Vaccinated mice survived a challenge of 100 times the 50% lethality dose (LD50 of wild-type S. Typhimurium. Protective efficacy against heterologous virulent Salmonella challenges was highly O-serotype related. Furthermore, broad-spectrum protection against S. Typhimurium, S. Enteritidis, and S. Choleraesuis was observed by co-vaccination of O9 and O7 O-serotype-converted vaccine candidates. This study highlights the strategy of expressing heterologous O-polysaccharides via genetic engineering in developing live attenuated S. Typhimurium vaccines against NTS infections.

  12. Efficacy of myrtle oil against Salmonella Typhimurium on fresh produce.

    Science.gov (United States)

    Gündüz, Gülten Tiryaki; Gönül, Sahika Aktuğ; Karapinar, Mehmet

    2009-03-31

    The antimicrobial activity of myrtle leaves (Myrtus communis) oil was tested against the nalidixic acid resistant strain of Salmonella Typhimurium ATCC 13311. An inoculum (100 microl, ca.10(8) cfu/ml) was deposited on the skin of whole tomatoes and 10 g of shredded iceberg lettuce, dried for 2 h at 22 degrees C and held for 22 h at 4 degrees C before treatments. Inoculated iceberg lettuce (3.51-3.99 log cfu/g) and tomatoes (3.47-4.86 log cfu/tomato) were treated with three different washing procedures for 5, 10, 15 and 20 min; washing with sterile distilled water (control), washing with three different concentrations of myrtle leaves oil and the last treatment was a combination of washing with myrtle leaves oil and then rinsing in sterile distilled water for 1 min. Washing with myrtle leaves oil with or without rinsing procedures caused significant reduction in S. Typhimurium population compared with the control after treatment for four different times (p0.05). The maximum logarithmic reductions of 1.66 cfu/g-1.89 cfu/tomato were respectively obtained on iceberg lettuce and tomatoes treated with 1000 ppm myrtle leaves oil without any rinsing treatment. The results suggest that the use of myrtle leaves oil is an innovative and useful tool as an alternative to the use of chlorine or other synthetic disinfectants in fruits and vegetables, especially for organic products.

  13. Stress response and virulence in Salmonella Typhimurium: a genomics approach

    NARCIS (Netherlands)

    Hermans, A.P.H.M.

    2007-01-01

    Since 1995 the number of human infections with Salmonella serovar Typhimurium DT104 increased in The Netherlands and abroad. The multi antibiotic resistance of this strain has been often proposed as plausible reason for this increase. Within his PhD research, Armand Hermans found novel DT104

  14. Large outbreaks of Salmonella Typhimurium infection in Denmark in 2008

    DEFF Research Database (Denmark)

    Ethelberg, S.; Wingstrand, Anne; Jensen, T.

    2008-01-01

    An outbreak of Salmonella Typhimurium phage type U292 has been ongoing in Denmark since 1 April, with 1,054 cases registered until 23 October 2008. Extensive investigations including hypothesis-generating interviews, matched case-control studies, cohort studies in embedded outbreaks, shopping list...

  15. Karakterisering van de zuurgevoeligheid van Salmonella typhimurium faagtype DT104

    NARCIS (Netherlands)

    de Jonge R; van Leusden FM; Dufrenne JB; Ritmeester WS; Delfgou-van Asch EHM; van Pelt W; LBG

    1999-01-01

    Het aantal gevallen van salmonellosis in Nederland veroorzaakt door Salmonella typhimurium faagtype DT104 is toegenomen van 10 in 1985 tot 163 in 1997 (10% van alle gevallen van salmonellosis). De stam lijkt zijn oorsprong te hebben in het Verenigd Koninkrijk. Daar wordt inmiddels 20% van alle

  16. Molecular Characterization of Salmonella Typhimurium Highly Successful Outbreak Strains

    DEFF Research Database (Denmark)

    Petersen, Randi Føns; Litrup, Eva; Larsson, Jonas T.

    2011-01-01

    Three large clusters of Salmonella Typhimurium infections in Denmark in 2008 and 2009 were defined by multilocus variable number of tandem repeat analysis (MLVA). One of these proved to be the hereto largest Danish cluster of salmonellosis with 1446 cases. Two smaller clusters with a total of 197...

  17. Eggshell membrane structure and penetration by Salmonella typhimurium.

    Science.gov (United States)

    Berrang, M E; Frank, J F; Buhr, R J; Bailey, J S; Cox, N A

    1999-01-01

    Eggshell membrane was removed from 10 broiler hatching eggs at approximately monthly intervals through the productive life of a commercial flock. A piece of membrane (2 by 2 cm) was used to cover an opening in an apparatus designed to test penetration by Salmonella Typhimurium. The membrane was placed between two chambers as the only means of liquid transfer. The chamber above the membrane was filled with a suspension of Salmonella Typhimurium cells. Sampling of the bottom chamber provided cultural evidence of the penetration by a marker strain of Salmonella Typhimurium. Samples were drawn at 15 min and at 1, 3, 5, 7, 12, 24, and 48 h. Following the cultural penetration experiment, the same pieces of membrane were removed and stained for microscopic examination. Membrane structure was examined with the use of a confocal laser scanning microscope. Each image consisted of a composite of eight 1-microm optical slices showing the fibers making up the outer surface of the membrane. These images were transferred to an image analysis software package that allowed the measurement of the interfiber area. No clear correlation could be made between the average size of all interfiber areas or the total interfiber area measured in the outer 8 microm of the outer membrane and the ability of Salmonella Typhimurium to penetrate the same piece of eggshell membrane.

  18. Antimicrobial Resistance Profiles of the Two Porcine Salmonella Typhimurium Isolates

    Directory of Open Access Journals (Sweden)

    Kemal METİNER

    2016-07-01

    Full Text Available The aim of the study is to detect the presence of the Salmonella species in swine with diarrhea, and to investigate their antimicrobial resistance and extended spectrum beta lactamase (ESBL and/or AmpC β-lactamase production. For this purpose, stool samples from three commercial pig farms in Istanbul and Tekirdag were collected and processed for Salmonella isolation by culture and isolates were identified by biochemical activity tests. Salmonella isolates were confirmed by PCR then serotyped. Antimicrobial resistance and ESBL and AmpC production of the isolates were determined according to the Clinical and Laboratory Standards Institute (CLSI standard. In the study, two hundred and thirty eight stool samples were examined. Salmonella spp. were obtained from 2 samples, and the isolation rate was determined as 0.8%. Both of the isolates were defined as Salmonella enterica subsp. enterica serovar Typhimurium (serotype 1, 4, [5], 12: I: 1, 2 by serotyping. Both of them were resistant to cefaclor, cloxacillin and lincomycin (100%. Multidrug resistance (resistance ≥3 antimicrobials observed in all isolates. ESBL and AmpC production were not detected in any of the isolates. To our knowledge, this is the first report of the isolation of S. Typhimurium in pigs with diarrhea in Turkey. This study also represents the first report of multi-drug resistant S. Typhimurium isolates from pig stools in Turkey.

  19. Pharmacokinetics and tissue distribution of amoxicillin in healthy and Salmonella Typhimurium-inoculated pigs

    DEFF Research Database (Denmark)

    Agerso, H.; Friis, C.; Nielsen, Jens

    2000-01-01

    Objective--To determine pharmacokinetics and tissue distribution of amoxicillin in healthy and Salmonella Typhimurium-inoculated pigs. Animals--12 healthy pigs and 12 S Typhimurium-inoculated pigs. Procedure-Concentration of amoxicillin in tissue was measured by use of high-performance liquid...... chromatography 4, 8, 12, and 24 hours after IM administration. Pharmacokinetic values of amoxicillin in plasma were assessed by use of a l-compartment model with first-order absorption. Results--Inoculation caused diarrhea and increased rectal temperature and WBC count. Absorption half-life was shorter...... pigs and from 0.22 to 0.36 in inoculated pigs. Conclusions and Clinical Relevance-Salmonella Typhimurium inoculation altered absorption of amoxicillin from the injection sire and prolonged elimination half-life. However, distribution of amoxicillin to intestinal tract tissue was only affected...

  20. The elimination of Salmonella typhimurium in coastal waters with various levels of microbiologically hygienic contamination.

    Science.gov (United States)

    Glaus, H; Heinemeyer, E A

    1994-12-01

    The biotic elimination of Salmonella typhimurium in coastal sea water is primarily caused by protozoa. The elimination is usually faster in summer than in winter and in the vicinity of waste water outlets partially faster than in coastal areas with less contamination. When the rate of elimination is measured twice in succession in the same sample (primary/secondary culture) the second reduction is considerably faster. This activation is attributed to the multiplication of protozoa (predator-prey-effect). The activation is also possible through E. coli in concentrations such as those found in waste from sewage treatment plants or by Salmonella typhimurium themselves and vice versa. After 12 hours incubation the number of E. coli in the primary culture was still about 58% of the original quantity and 12 hours after a renewed inoculation in the secondary culture only 1%. When salmonella were added to the primary culture it was already impossible to detect E. coli after 12 hours in the secondary culture. Salmonella showed comparable tendencies, although the elimination of salmonella was clearly slower than the elimination of E. coli even after activation with salmonella. In the primary culture E. coli is already recultivatable in a smaller quantity than salmonella. Furthermore the addition of Cycloheximide to the secondary culture provides a considerably better protection for salmonella than for E. coli, so that it can be assumed that other or additional factors are involved in the elimination of E. coli.

  1. Virulence of invasive Salmonella Typhimurium ST313 in animal models of infection.

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    Girish Ramachandran

    2017-08-01

    Full Text Available Salmonella Typhimurium sequence type (ST 313 produces septicemia in infants in sub-Saharan Africa. Although there are known genetic and phenotypic differences between ST313 strains and gastroenteritis-associated ST19 strains, conflicting data about the in vivo virulence of ST313 strains have been reported. To resolve these differences, we tested clinical Salmonella Typhimurium ST313 and ST19 strains in murine and rhesus macaque infection models. The 50% lethal dose (LD50 was determined for three Salmonella Typhimurium ST19 and ST313 strains in mice. For dissemination studies, bacterial burden in organs was determined at various time-points post-challenge. Indian rhesus macaques were infected with one ST19 and one ST313 strain. Animals were monitored for clinical signs and bacterial burden and pathology were determined. The LD50 values for ST19 and ST313 infected mice were not significantly different. However, ST313-infected BALB/c mice had significantly higher bacterial numbers in blood at 24 h than ST19-infected mice. ST19-infected rhesus macaques exhibited moderate-to-severe diarrhea while ST313-infected monkeys showed no-to-mild diarrhea. ST19-infected monkeys had higher bacterial burden and increased inflammation in tissues. Our data suggest that Salmonella Typhimurium ST313 invasiveness may be investigated using mice. The non-human primate results are consistent with clinical data, suggesting that ST313 strains do not cause diarrhea.

  2. Inhibitory Effects of Several Essential Oils towards Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B

    Directory of Open Access Journals (Sweden)

    S.F. Mazhar

    2014-09-01

    Full Text Available Plant essential oils are natural products extracted from plants and because of their antimicrobial properties can be used as natural additives in foods. They are also useful for decontamination of food-borne pathogens and can be a safe additive in foods. The antimicrobial activities of essential oils belonging to Saturiea hortensis, Thymus vulgaris, Mentha polegium, Cuminum cyminum, Lavandula officinalis and Mentha viridis L. (spearmint were investigated at different concentrations (0.1, 0.3, 0.5, 1, 2, 5 and 10%v/v against Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B by using the agar well diffusion method. Essential oils showed inhibitory effect on Salmonella spp. in the agar well diffusion assay. In addition, the capability of essential oils for decontamination of minced row beef, ground beef, minced raw chicken and minced raw fish inoculated with Salmonella spp. at 0.1 and 0.5%v/v were assessed. Reduction of the Salmonella spp. population was observed following the inoculation of the cultures with 0.1 and 0.5%v/v essential oils.

  3. Ingress of Salmonella enterica Typhimurium into tomato leaves through hydathodes.

    Directory of Open Access Journals (Sweden)

    Ganyu Gu

    Full Text Available Internal contamination of Salmonella in plants is attracting increasing attention for food safety reasons. In this study, three different tomato cultivars "Florida Lanai", "Crown Jewel", "Ailsa Craig" and the transgenic line Sp5 of "Ailsa Craig" were inoculated with 1 µl GFP-labeled Salmonella Typhimurium through guttation droplets at concentrations of 10(9 or 10(7 CFU/ml. Survival of Salmonella on/in tomato leaves was detected by both direct plating and enrichment methods. Salmonella cells survived best on/in the inoculated leaves of cultivar "Ailsa Craig" and decreased fastest on/in "Florida Lanai" leaves. Increased guttation in the abscisic acid over-expressing Sp5 plants may have facilitated the entrance of Salmonella into leaves and the colonization on the surface of tomato leaves. Internalization of Salmonella Typhimurium in tomato leaves through guttation drop inoculation was confirmed by confocal laser microscopy. For the first time, convincing evidence is presented that S. enterica can enter tomato leaves through hydathodes and move into the vascular system, which may result in the internal translocation of the bacteria inside plants.

  4. Distribution of Salmonella typhimurium in romaine lettuce leaves.

    Science.gov (United States)

    Kroupitski, Yulia; Pinto, Riky; Belausov, Eduard; Sela, Shlomo

    2011-08-01

    Leafy greens are occasionally involved in outbreaks of enteric pathogens. In order to control the plant contamination it is necessary to understand the factors that influence enteric pathogen-plant interactions. Attachment of Salmonella enterica serovar typhimurium to lettuce leaves has been demonstrated before; however, only limited information is available regarding the localization and distribution of immigrant Salmonella on the leaf surface. To extend our knowledge regarding initial pathogen-leaf interactions, the distribution of green-fluorescent protein-labeled Salmonella typhimurium on artificially contaminated romaine lettuce leaves was analyzed. We demonstrate that attachment of Salmonella to different leaf regions is highly variable; yet a higher attachment level was observed on leaf regions localized close to the petiole (7.7 log CFU g(-1)) compared to surfaces at the far-end region of the leaf blade (6.2 log CFU g(-1)). Attachment to surfaces located at a central leaf region demonstrated intermediate attachment level (7.0 log CFU g(-1)). Salmonella displayed higher affinity toward the abaxial side compared to the adaxial side of the same leaf region. Rarely, Salmonella cells were also visualized underneath stomata within the parenchymal tissue, supporting the notion that this pathogen can also internalize romaine lettuce leaves. Comparison of attachment to leaves of different ages showed that Salmonella displayed higher affinity to older compared to younger leaves (1.5 log). Scanning electron microscopy revealed a more complex topography on the surface of older leaves, as well as on the abaxial side of the examined leaf tissue supporting the notion that a higher attachment level might be correlated with a more composite leaf landscape. Our findings indicate that initial attachment of Salmonella to romaine lettuce leaf depends on multiple plant factors pertaining to the specific localization on the leaf tissue and to the developmental stage of the leaf

  5. Salmonella typhimurium activates virulence gene transcription within acidified macrophage phagosomes.

    Science.gov (United States)

    Alpuche Aranda, C M; Swanson, J A; Loomis, W P; Miller, S I

    1992-01-01

    Survival of Salmonella typhimurium within macrophage phagosomes requires the coordinate expression of bacterial gene products. This report examines the contribution of phagosomal pH as a signal for expression of genes positively regulated by the S. typhimurium virulence regulators PhoP and PhoQ. Several hours after bacterial phagocytosis by murine bone marrow-derived macrophages, PhoP-activated gene transcription increased 50- to 77-fold. In contrast, no difference in PhoP-activated gene expression was observed after infection of cultured epithelial cells, suggesting that the membrane sensor PhoQ recognized signals unique to macrophage phagosomes. The increase in PhoP-regulated gene expression was abolished when macrophage culture medium contained NH4Cl or chloroquine, weak bases that raise the pH of acidic compartments. Measurements of pH documented that S. typhimurium delayed and attenuated acidification of its intracellular compartment. Phagosomes containing S. typhimurium required 4-5 hr to reach pH < 5.0. In contrast, within 1 hr vacuoles containing heat-killed bacteria were measured at pH < 4.5. The eventual acidification of phagosomes to pH < 5.0 correlated with the period of maximal PhoP-dependent gene expression. These observations implicate phagosome acidification as an intracellular inducer of PhoP-regulated gene expression and suggest that Salmonella survival is dependent on its ability to attenuate phagosome acidification. Images PMID:1438196

  6. Phage-Coupled Piezoelectric Biodetector for Salmonella Typhimurium

    Science.gov (United States)

    2005-08-01

    urethritis, cervicitis, and rarely carditis (Tauxe, 1992). Antimicrobial resistance to Salmonella is associated with increased antibiotic use to promote the... growth of feed animals and poultry (Hamer and Gill, 2002). S. typhimurium Definitive Type 104 is the worst emerging pathogenic strain, being resistant...From the farm to the kitchen table: the negative impact of antimicrobial use in animals on humans. Nutr. Rev. 60, 261-264. Hartman, N.F., Wyvill, J.C

  7. Heat Survival and Phenotype Microarray Profiling of Salmonella Typhimurium Mutants.

    Science.gov (United States)

    Dawoud, Turki M; Khatiwara, Anita; Park, Si Hong; Davis, Morgan L; Baker, Christopher A; Ricke, Steven C; Kwon, Young Min

    2017-02-01

    Contamination of food products by pathogenic microorganisms continues to be a major public health and food industry concern. Non-typhoidal Salmonella species have led to numerous outbreaks associated with various foods. A wide variety of methods have been applied and introduced for treatment of fresh foods to eliminate pathogenic as well as spoilage microorganisms. Salmonella can become exposed to elevated temperatures while associated with hosts such as poultry. In addition, heat treatment is also applied at various stages of processing to retain the shelf life of food products. Despite this, these microorganisms may overcome exposure to such treatments through the efficient expression of stress response mechanisms and result in illness following consumption. Thermal stress induces a range of destructive exposures to bacterial cells such as protein damage and DNA damage caused by reactive oxygen species. In this study, we chose three genes (∆recD, ∆STM14_5307, and ∆aroD) associated with conditionally essential genes required for different aspects of optimal growth at 42 °C and evaluated the responses of wild type and mutant Salmonella Typhimurium strains to uncover potential mechanisms that may enable survival and resistance under thermal stress. The RecBCD complex that initiates repair of double-stranded DNA breaks through homologous recombination. STM14_5307 is a transcriptional regulator involved in stationary phase growth and inositol metabolism. The gene aroD is involved in metabolism and stationary phase growth. These strains were characterized via high throughput phenotypic profiling in response to two different growth temperatures (37 °C (human host temperature) and 42 °C (poultry host temperature)). The ∆aroD strain exhibited the highest sensitivity to the various temperatures followed by the ∆recD and ∆STM14_5307 strains, respectively. Achieving more understanding of the molecular mechanisms of heat survival may lead to the development

  8. Salmonella Typhimurium exploits inflammation to its own advantage in piglets

    Directory of Open Access Journals (Sweden)

    Barbara eChirullo

    2015-09-01

    Full Text Available Salmonella Typhimurium (S. Typhimurium is responsible for foodborne zoonotic infections that, in humans, induce self-limiting gastroenteritis. The aim of this study was to evaluate whether the wild-type strain S. Typhimurium (STM14028 is able to exploit inflammation fostering an active infection.Due to the similarity between human and porcine diseases induced by S. Typhimurium, we used piglets as a model for salmonellosis and gastrointestinal research. This study showed that STM14028 is able to efficiently colonize in vitro porcine mono-macrophages and intestinal columnar epithelial (IPEC-J2 cells, and that the colonization significantly increases with LPS pre-treatment. This increase was then reversed by inhibiting the LPS stimulation through LPS antagonist, confirming an active role of LPS stimulation in the STM14028-intracellular colonization. Moreover, LPS in vivo treatment induces increased cytokines blood level and body temperature at 4 hours post infection, which is consistent with an acute inflammatory stimulus, capable to influence the colonization of STM14028 in different organs and tissues. The present study proves for the first time that in acute enteric salmonellosis, S.Typhimurium exploits inflammation for its benefit in piglets.

  9. Salmonella Typhimurium and multidirectional communication in the gut

    Directory of Open Access Journals (Sweden)

    Elena V. Gart

    2016-11-01

    Full Text Available The mammalian digestive tract is home to trillions of microbes, including bacteria, archaea, protozoa, fungi and viruses. In monogastric mammals the stomach and small intestine harbor diverse bacterial populations but are typically less populated than the colon. The gut bacterial community (microbiota hereafter varies widely among different host species and individuals within a species. It is influenced by season of the year, age of the host, stress and disease. Ideally, the host and microbiota benefit each other. The host provides nutrients to the microbiota and the microbiota assists the host with digestion and nutrient metabolism. The resident microbiota competes with pathogens for space and nutrients and, through this competition, protects the host in a phenomenon called colonization resistance. The microbiota participates in development of the host immune system, particularly regulation of autoimmunity and mucosal immune response. The microbiota also shapes gut-brain communication and host responses to stress; and, indeed, the microbiota is a newly recognized endocrine organ within mammalian hosts.Salmonella enterica serovar Typhimurium (S. Typhimurium hereafter is a food-borne pathogen which adapts to and alters the gastrointestinal (GI environment. In the GI tract, S. Typhimurium competes with the microbiota for nutrients and overcomes colonization resistance to establish infection. To do this, S. Typhimurium uses multiple defense mechanisms to resist environmental stressors, like the acidic pH of the stomach, and virulence mechanisms which allow it to invade the intestinal epithelium and disseminate throughout the host. To coordinate gene expression and disrupt signaling within the microbiota and between host and microbiota, S. Typhimurium employs its own chemical signaling and may regulate host hormone metabolism.This review will discuss the multidirectional interaction between S. Typhimurium, host and microbiota as well as mechanisms

  10. An outbreak of multidrug-resistant, quinolone-resistant Salmonella enterica serotype typhimurium DT104

    DEFF Research Database (Denmark)

    Molbak, K.; Baggesen, Dorte Lau; Aarestrup, Frank Møller

    1999-01-01

    Background Food-borne salmonella infections have become a major problem in industrialized countries. The strain of Salmonella enterica serotype typhimurium known as definitive phage type 104 (DT104) is usually resistant to five drugs: ampicillin, chloramphenicol, streptomycin, sulfonamides...

  11. Hydrogen-Stimulated Gene Expression by Salmonella enterica serovar Typhimurium in a Carbon Limited Environment

    Science.gov (United States)

    Background: Salmonella enterica serovar Typhimurium can utilize molecular hydrogen for growth and amino acid transport during anaerobic growth in a carbon limited environment. In this study we identified hydrogen-stimulated gene expression changes contributing to Salmonella survival. Methods: Micr...

  12. Constraint-based analysis of metabolic capacity of Salmonella typhimurium during host-pathogen interaction

    Directory of Open Access Journals (Sweden)

    Palsson Bernhard

    2009-04-01

    Full Text Available Abstract Background Infections with Salmonella cause significant morbidity and mortality worldwide. Replication of Salmonella typhimurium inside its host cell is a model system for studying the pathogenesis of intracellular bacterial infections. Genome-scale modeling of bacterial metabolic networks provides a powerful tool to identify and analyze pathways required for successful intracellular replication during host-pathogen interaction. Results We have developed and validated a genome-scale metabolic network of Salmonella typhimurium LT2 (iRR1083. This model accounts for 1,083 genes that encode proteins catalyzing 1,087 unique metabolic and transport reactions in the bacterium. We employed flux balance analysis and in silico gene essentiality analysis to investigate growth under a wide range of conditions that mimic in vitro and host cell environments. Gene expression profiling of S. typhimurium isolated from macrophage cell lines was used to constrain the model to predict metabolic pathways that are likely to be operational during infection. Conclusion Our analysis suggests that there is a robust minimal set of metabolic pathways that is required for successful replication of Salmonella inside the host cell. This model also serves as platform for the integration of high-throughput data. Its computational power allows identification of networked metabolic pathways and generation of hypotheses about metabolism during infection, which might be used for the rational design of novel antibiotics or vaccine strains.

  13. InduciblespyTranscription Acts as a Sensor for Envelope Stress ofSalmonella typhimurium.

    Science.gov (United States)

    Jeong, Seon Mi; Lee, Hwa Jeong; Park, Yoon Mee; Kim, Jin Seok; Lee, Sang Dae; Bang, Iel Soo

    2017-01-01

    Salmonella enterica infects a broad range of host animals, and zoonostic infection threatens both public health and the livestock and meat processing industries. Many antimicrobials have been developed to target Salmonella envelope that performs essential bacterial functions; however, there are very few analytical methods that can be used to validate the efficacy of these antimicrobials. In this study, to develop a potential biosensor for Salmonella envelope stress, we examined the transcription of the S. enterica serovar typhimurium spy gene, the ortholog of which in Escherichia coli encodes Spy (spheroplast protein y). Spy is a chaperone protein expressed and localized in the periplasm of E. coli during spheroplast formation, or by exposure to protein denaturing conditions. spy expression in S. typhimurium was examined by constructing a spy-gfp transcriptional fusion. S. typhimurium spy transcription was strongly induced during spheroplast formation, and also when exposed to membrane-disrupting agents, including ethanol and the antimicrobial peptide polymyxin B. Moreover, spy induction required the activity of regulator proteins BaeR and CpxR, which are part of the major envelope stress response systems BaeS/BaeR and CpxA/CpxR, respectively. Results suggest that monitoring spy transcription may be useful to determine whether a molecule particularly cause envelope stress in Salmonella .

  14. Persistence of salmonella Typhimurium in Nopal

    Science.gov (United States)

    Having documented information available on the capability of Salmonella to remain in the cladode tissue it is important to understand the role of nopal on the lifecycle of enteropathogenic bacteria in humans, as well as for management and control programs of theses pathogens in plants. Because of th...

  15. Persistence of salmonella typhimurium in nopal cladodes

    Science.gov (United States)

    Fresh produce associated outbreaks have increased in the last few years. E.coli O157:H7 and Salmonella have been causative agents of infection in these outbreaks. Fresh produce is consumed raw, and in the absence of terminal kill treatment, it is imperative to understand sources of contamination o...

  16. Outbreak of Salmonella Typhimurium 44 related to egg consumption.

    Science.gov (United States)

    Dyda, Amalie; Hundy, Rebecca; Moffatt, Cameron R M; Cameron, Scott

    2009-12-01

    ACT Health investigated an outbreak of gastroenteritis associated with a local restaurant in December 2008. The infecting agent was Salmonella serotype Typhimurium phage type 44. A case control study was conducted to identify the source of infection. A total of 22 cases and 9 controls were recruited to take part in the study. Both poached eggs (odds ratio [OR] 42.00) and hollandaise sauce (OR 19.00) had elevated odds ratios that were statistically significant. The major limitation of the study was the small sample size and small number of controls. Despite this, a strong association with illness and consumption of eggs and hollandaise sauce was detected and this was further supported by environmental evidence. The investigation concluded that the cause of the outbreak was putatively contaminated eggs, either on their own or as an ingredient used in hollandaise sauce. The investigation and control measures led to an improvement in hygiene practices at the restaurant and contributed to the voluntary recall of the contaminated batch of eggs from the Australian Capital Territory. The results of the study also build upon other evidence that egg-related salmonellosis is now common in Australia and attention to commercial practices at production and processing is overdue.

  17. Whole-Genome Sequencing Identifies In Vivo Acquisition of a blaCTX-M-27-Carrying IncFII Transmissible Plasmid as the Cause of Ceftriaxone Treatment Failure for an Invasive Salmonella enterica Serovar Typhimurium Infection

    Science.gov (United States)

    McCollister, Bruce; Kotter, Cassandra V.; Frank, Daniel N.; Washburn, Taylor

    2016-01-01

    We report a case of ceftriaxone treatment failure for bacteremia caused by Salmonella enterica subsp. enterica serovar Typhimurium, due to the in vivo acquisition of a blaCTX-M-27-encoding IncFII group transmissible plasmid. The original β-lactamase-susceptible isolate ST882S was replaced by the resistant isolate ST931R during ceftriaxone treatment. After relapse, treatment was changed to ciprofloxacin, and the patient recovered. Isolate ST931R could transfer resistance to Escherichia coli at 37°C. We used whole-genome sequencing of ST882S and ST931R, the E. coli transconjugant, and isolated plasmid DNA to unequivocally show that ST882S and ST931R had identical chromosomes, both having 206 identical single-nucleotide polymorphisms (SNPs) versus S. Typhimurium 14028s. We assembled a complete circular genome for ST931R, to which ST882S reads mapped with no SNPs. ST882S and ST931R were isogenic except for the presence of three additional plasmids in ST931R. ST931R and the E. coli transconjugant were ceftriaxone resistant due to the presence of a 60.5-kb IS26-flanked, blaCTX-M-27-encoding IncFII plasmid. Compared to 14082s, ST931R has almost identical Gifsy-1, Gifsy-2, and ST64B prophages, lacks Gifsy-3, and instead carries a unique Fels-2 prophage related to that found in LT2. ST882S and ST931R both had a 94-kb virulence plasmid showing >99% identity with pSLT14028s and a cryptic 3,904-bp replicon; ST931R also has cryptic 93-kb IncI1 and 62-kb IncI2 group plasmids. To the best of our knowledge, in vivo acquisition of extended-spectrum β-lactamase resistance by S. Typhimurium and blaCTX-M-27 genes in U.S. isolates of Salmonella have not previously been reported. PMID:27671066

  18. Importance of sigma factor mutations in increased triclosan resistance in Salmonella Typhimurium

    DEFF Research Database (Denmark)

    Gantzhorn, Mette Rørbæk; Olsen, John Elmerdahl; Thomsen, Line Elnif

    2015-01-01

    BACKGROUND: Salmonella enterica is the second most common foodborne pathogen. The use of biocides is crucial to prevent spread of foodborne pathogens, and it would be devastating for food safety if Salmonella would become resistant to the disinfectants used. Another concern is that exposure...... to disinfectants might lead to decreased susceptibility to antibiotics. The current study aimed to identify genetic changes causing high level triclosan resistance in S. enterica serovar Typhimurium and evaluate how these affected antibiotic resistance and efflux pump activity. RESULTS: Wild type strains S....... Typhimurium 4/74 and DTU3 were adapted to increasing concentrations of the biocide triclosan by serial passage. High level triclosan resistant isolates (MIC > 1000 μg/ml) were obtained. Strains were genome sequenced, and SNPs in fabI, rpoS and rpoD were found to be associated with high level resistance...

  19. Salmonella enterica serovar Typhimurium ΔmsbB Triggers Exacerbated Inflammation in Nod2 Deficient Mice

    Science.gov (United States)

    Claes, Anne-Kathrin; Steck, Natalie; Schultz, Dorothee; Zähringer, Ulrich; Lipinski, Simone; Rosenstiel, Philip; Geddes, Kaoru; Philpott, Dana J.; Heine, Holger; Grassl, Guntram A.

    2014-01-01

    The intracellular pathogen Salmonella enterica serovar Typhimurium causes intestinal inflammation characterized by edema, neutrophil influx and increased pro-inflammatory cytokine expression. A major bacterial factor inducing pro-inflammatory host responses is lipopolysaccharide (LPS). S. Typhimurium ΔmsbB possesses a modified lipid A, has reduced virulence in mice, and is being considered as a potential anti-cancer vaccine strain. The lack of a late myristoyl transferase, encoded by MsbB leads to attenuated TLR4 stimulation. However, whether other host receptor pathways are also altered remains unclear. Nod1 and Nod2 are cytosolic pattern recognition receptors recognizing bacterial peptidoglycan. They play important roles in the host's immune response to enteric pathogens and in immune homeostasis. Here, we investigated how deletion of msbB affects Salmonella's interaction with Nod1 and Nod2. S. Typhimurium Δ msbB-induced inflammation was significantly exacerbated in Nod2−/− mice compared to C57Bl/6 mice. In addition, S. Typhimurium ΔmsbB maintained robust intestinal colonization in Nod2−/− mice from day 2 to day 7 p.i., whereas colonization levels significantly decreased in C57Bl/6 mice during this time. Similarly, infection of Nod1−/− and Nod1/Nod2 double-knockout mice revealed that both Nod1 and Nod2 play a protective role in S. Typhimurium ΔmsbB-induced colitis. To elucidate why S. Typhimurium ΔmsbB, but not wild-type S. Typhimurium, induced an exacerbated inflammatory response in Nod2−/− mice, we used HEK293 cells which were transiently transfected with pathogen recognition receptors. Stimulation of TLR2-transfected cells with S. Typhimurium ΔmsbB resulted in increased IL-8 production compared to wild-type S. Typhimurium. Our results indicate that S. Typhimurium ΔmsbB triggers exacerbated colitis in the absence of Nod1 and/or Nod2, which is likely due to increased TLR2 stimulation. How bacteria with “genetically detoxified” LPS

  20. Rapid detection of Salmonella typhimurium on fresh spinach leaves using phage-immobilized magnetoelastic biosensors

    Science.gov (United States)

    Horikawa, Shin; Li, Suiqiong; Chai, Yating; Park, Mi-Kyung; Shen, Wen; Barbaree, James M.; Vodyanoy, Vitaly J.; Chin, Bryan A.

    2011-06-01

    This paper presents an investigation into the use of magnetoelastic biosensors for the rapid detection of Salmonella typhimurium on fresh spinach leaves. The biosensors used in this investigation were comprised of a strip-shaped, goldcoated sensor platform (2 mm-long) diced from a ferromagnetic, amorphous alloy and a filamentous fd-tet phage which specifically binds with S. typhimurium. After surface blocking with bovine serum albumin, these biosensors were, without any preceding sample preparation, directly placed on wet spinach leaves inoculated with various concentrations of S. typhimurium. Upon contact with cells, the phage binds S. typhimurium to the sensor thereby increasing the total mass of the sensor. This change in mass causes a corresponding decrease in the sensor's resonant frequency. After 25 min, the sensors were collected from the leaf surface and measurements of the resonant frequency were performed immediately. The total assay time was less than 30 min. The frequency changes for measurement sensors (i.e., phageimmobilized) were found to be statistically different from those for control sensors (sensors without phage), down to 5 × 106 cells/ml. The detection limit may be improved by using smaller, micron-sized sensors that will have a higher probability of contacting Salmonella on the rough surfaces of spinach leaves.

  1. Comparative genome analysis of the high pathogenicity Salmonella Typhimurium strain UK-1.

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    Yingqin Luo

    Full Text Available Salmonella enterica serovar Typhimurium, a gram-negative facultative rod-shaped bacterium causing salmonellosis and foodborne disease, is one of the most common isolated Salmonella serovars in both developed and developing nations. Several S. Typhimurium genomes have been completed and many more genome-sequencing projects are underway. Comparative genome analysis of the multiple strains leads to a better understanding of the evolution of S. Typhimurium and its pathogenesis. S. Typhimurium strain UK-1 (belongs to phage type 1 is highly virulent when orally administered to mice and chickens and efficiently colonizes lymphoid tissues of these species. These characteristics make this strain a good choice for use in vaccine development. In fact, UK-1 has been used as the parent strain for a number of nonrecombinant and recombinant vaccine strains, including several commercial vaccines for poultry. In this study, we conducted a thorough comparative genome analysis of the UK-1 strain with other S. Typhimurium strains and examined the phenotypic impact of several genomic differences. Whole genomic comparison highlights an extremely close relationship between the UK-1 strain and other S. Typhimurium strains; however, many interesting genetic and genomic variations specific to UK-1 were explored. In particular, the deletion of a UK-1-specific gene that is highly similar to the gene encoding the T3SS effector protein NleC exhibited a significant decrease in oral virulence in BALB/c mice. The complete genetic complements in UK-1, especially those elements that contribute to virulence or aid in determining the diversity within bacterial species, provide key information in evaluating the functional characterization of important genetic determinants and for development of vaccines.

  2. Salmonella enterica Serovar Typhimurium Strategies for Host Adaptation

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    Christopher J. Anderson

    2017-10-01

    Full Text Available Bacterial pathogens must sense and respond to newly encountered host environments to regulate the expression of critical virulence factors that allow for niche adaptation and successful colonization. Among bacterial pathogens, non-typhoidal serovars of Salmonella enterica, such as serovar Typhimurium (S. Tm, are a primary cause of foodborne illnesses that lead to hospitalizations and deaths worldwide. S. Tm causes acute inflammatory diarrhea that can progress to invasive systemic disease in susceptible patients. The gastrointestinal tract and intramacrophage environments are two critically important niches during S. Tm infection, and each presents unique challenges to limit S. Tm growth. The intestinal tract is home to billions of commensal microbes, termed the microbiota, which limits the amount of available nutrients for invading pathogens such as S. Tm. Therefore, S. Tm encodes strategies to manipulate the commensal population and side-step this nutritional competition. During subsequent stages of disease, S. Tm resists host immune cell mechanisms of killing. Host cells use antimicrobial peptides, acidification of vacuoles, and nutrient limitation to kill phagocytosed microbes, and yet S. Tm is able to subvert these defense systems. In this review, we discuss recently described molecular mechanisms that S. Tm uses to outcompete the resident microbiota within the gastrointestinal tract. S. Tm directly eliminates close competitors via bacterial cell-to-cell contact as well as by stimulating a host immune response to eliminate specific members of the microbiota. Additionally, S. Tm tightly regulates the expression of key virulence factors that enable S. Tm to withstand host immune defenses within macrophages. Additionally, we highlight the chemical and physical signals that S. Tm senses as cues to adapt to each of these environments. These strategies ultimately allow S. Tm to successfully adapt to these two disparate host environments. It is

  3. The engineered Salmonella typhimurium inhibits tumorigenesis in advanced glioma

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    Chen JQ

    2015-09-01

    Full Text Available Jian-qiang Chen,1 Yue-fu Zhan,2 Wei Wang,1 Sheng-nan Jiang,2,3 Xiang-ying Li21Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China; 2Department of Radiology, Affiliated to Haikou Hospital Xiangya School of Medicine, Central South University, Haikou, People’s Republic of China; 3Department of Nuclear Medicine, Central South University Xiangya School of Medicine Affiliated HaiKou Hospital, Haikou, Hainan, People’s Republic of ChinaObjective: To explore the antitumor role of the attenuated Salmonella typhimurium ΔppGpp with inducible cytolysin A (ClyA in advanced stage of glioma.Materials and methods: The C6 rat glioma cells were orthotopically implanted by surgery into the caudate nucleus of rat brains. The rats were then randomly divided into the treatment group (SL + ClyA (n=12, negative control group (SL (n=12, and control group (phosphate-buffered saline [PBS] (n=12. In the treatment group, the attenuated S. typhimurium were transformed with the plasmid-encoded antitumor gene ClyA. The expression of ClyA was controlled by the TetR-regulated promoter in response to extracellular doxycycline. The plasmid also contained an imaging gene lux to allow illumination of the tumor infected by the bacteria. The rat glioma C6 cells were implanted into the caudate nucleus of all rats. The engineered S. typhimurium and respective controls were injected intravenously into the rats 21 days after initial tumor implantation. The pathological analysis of the glioma tumor was performed at 21 days and 28 days (7 days after doxycycline treatment postimplantation. All rats underwent MRI (magnetic resonance imaging and bioluminescence study at 21 days and 28 days postimplantation to detect tumor volume. The differences between the three groups in tumor volume and survival time were analyzed.Results: Advanced stage glioma  was detected at 21 days postimplantation. Bioluminescence showed that the

  4. Gamma irradiation or CD4+-T-cell depletion causes reactivation of latent Salmonella enterica serovar Typhimurium infection in C3H/HeN mice.

    NARCIS (Netherlands)

    Diepen, A. van; Gevel, J.S. van de; Koudijs, M.; Ossendorp, F.; Beekhuizen, H.; Janssen, R.; Dissel, J.T. van

    2005-01-01

    Upon infection with Salmonella, a host develops an immune response to limit bacterial growth and kill and eliminate the pathogen. Salmonella has evolved mechanisms to remain dormant within the body, only to reappear (reactivate) at a later time when the immune system is abated. We have developed an

  5. [Salmonella enterica serovar typhimurium infection presenting as a retrocecal mass in an 8-year-old child].

    Science.gov (United States)

    Belle Mbou, V; Vu Thien, H; Thuilleux, G; Ducou Le Pointe, H; Grand d'Esnon, A; Coulomb, A

    2010-11-01

    Minor salmonellosis is due to Gram-negative bacilli, which usually cause enterocolitis with potentially severe complications. We report on a case of a clinically uncommon presentation of Salmonella enterica serovar typhimurium infection in an 8-year-old child who presented with acute abdominal pain. We discuss clinically uncommon presentations of salmonella disease in children, as well as its pathology and radiology. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  6. Ecology and modelling of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in cattle manure and soil

    NARCIS (Netherlands)

    Semenov, A.V.

    2008-01-01

    The number of food poisoning cases caused by enteropathogens has increased in recent years. A significant part of the outbreaks associated with the consumption of raw vegetables has been attributed to Escherichia coli O157:H7 and Salmonella enterica subsp. enterica serovar Typhimurium. Bovine manure

  7. Phage types of Salmonella enterica ssp. enterica serovar Typhimurium isolated from production animals and humans in Denmark

    DEFF Research Database (Denmark)

    Baggesen, Dorte Lau; Wegener, Henrik Caspar

    1994-01-01

    S. Typhimurium is one of the 2 most common salmonella serotypes causing human salmonellosis in Denmark. In order to illustrate the significance of different production animals as a source of infection, 1461 isolates were characterized by phage typing. The isolates originated from human patients...

  8. Social stress increases fecal shedding of Salmonella typhimurium by early weaned piglets.

    Science.gov (United States)

    Callaway, T R; Morrow, J L; Edrington, T S; Genovese, K J; Dowd, S; Carroll, J; Dailey, J W; Harvey, R B; Poole, T L; Anderson, R C; Nisbet, D J

    2006-09-01

    "Segregated early weaning" (SEW) of pigs reduces exposure to pathogenic bacteria, but upon arrival at grower facilities pigs may be co-mingled regardless of farm of origin. The present study was designed to examine the effect of mixing (social) stress on populations of Salmonella enterica Typhimurium in SEW pigs. Piglets (7 days old; n = 28 in each of 2 replicates) were separated into 2 treatments (control and mixed groups) of 2 pens per treatment (7 piglets/pen). One (n = 1) "seeder" pig/pen was inoculated with 10(9) CFU of S. Typhimurium. Each seeder was placed with non-inoculated "contact" piglets (n = 6). A"contact" piglet was swapped each day between the "mixed" pens for 5 days; pigs in control pens were not exchanged. On day 5, the incidence of fecal Salmonella shedding was higher in the mixed contact pigs (P weaned pigs may increase susceptibility to and/or fecal shedding of Salmonella. Food-borne Salmonella infections in the United States are estimated to cost the economy dollar 2.4 billion annually (ERS/USDA, 2001). Approximately 6-9% of human salmonellosis is associated with the consumption of pork products (Frenzen et al., 1999). Salmonella is relatively common on swine farms and has been isolated from all stages of the pork production chain (Davies et al., 1999; Fedorka-Cray et al., 1997b; Rostagno et al., 2003). Salmonella is a threat to the pork industry not only from a food-safety perspective as a public health concern, but some Salmonella serotypes can cause clinical illnesses in swine, negatively impacting production efficiency and profitability (Schwartz, 1991).

  9. Salmonella enterica serovar Typhimurium lacking hfq gene confers protective immunity against murine typhoid.

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    Uday Shankar Allam

    Full Text Available Salmonella enterica is an important enteric pathogen and its various serovars are involved in causing both systemic and intestinal diseases in humans and domestic animals. The emergence of multidrug-resistant strains of Salmonella leading to increased morbidity and mortality has further complicated its management. Live attenuated vaccines have been proven superior over killed or subunit vaccines due to their ability to induce protective immunity. Of the various strategies used for the generation of live attenuated vaccine strains, focus has gradually shifted towards manipulation of virulence regulator genes. Hfq is a RNA chaperon which mediates the binding of small RNAs to the mRNA and assists in post-transcriptional gene regulation in bacteria. In this study, we evaluated the efficacy of the Salmonella Typhimurium Δhfq strain as a candidate for live oral vaccine in murine model of typhoid fever. Salmonella hfq deletion mutant is highly attenuated in cell culture and animal model implying a significant role of Hfq in bacterial virulence. Oral immunization with the Salmonella hfq deletion mutant efficiently protects mice against subsequent oral challenge with virulent strain of Salmonella Typhimurium. Moreover, protection was induced upon both multiple as well as single dose of immunizations. The vaccine strain appears to be safe for use in pregnant mice and the protection is mediated by the increase in the number of CD4(+ T lymphocytes upon vaccination. The levels of serum IgG and secretory-IgA in intestinal washes specific to lipopolysaccharide and outer membrane protein were significantly increased upon vaccination. Furthermore, hfq deletion mutant showed enhanced antigen presentation by dendritic cells compared to the wild type strain. Taken together, the studies in murine immunization model suggest that the Salmonella hfq deletion mutant can be a novel live oral vaccine candidate.

  10. Innate secretory antibodies protect against natural Salmonella typhimurium infection.

    Science.gov (United States)

    Wijburg, Odilia L C; Uren, Tania K; Simpfendorfer, Kim; Johansen, Finn-Eirik; Brandtzaeg, Per; Strugnell, Richard A

    2006-01-23

    The production of IgA is induced in an antigen-unspecific manner by commensal flora. These secretory antibodies (SAbs) may bind multiple antigens and are thought to eliminate commensal bacteria and self-antigens to avoid systemic recognition. In this study, we addressed the role of "innate" SAbs, i.e., those that are continuously produced in normal individuals, in protection against infection of the gastrointestinal tract. We used polymeric immunoglobulin receptor (pIgR-/-) knock-out mice, which are unable to bind and actively transport dimeric IgA and pentameric IgM to the mucosae, and examined the role of innate SAbs in protection against the invasive pathogen Salmonella typhimurium. In vitro experiments suggested that innate IgA in pIgR-/- serum bound S. typhimurium in a cross-reactive manner which inhibited epithelial cell invasion. Using a "natural" infection model, we demonstrated that pIgR-/- mice are profoundly sensitive to infection with S. typhimurium via the fecal-oral route and, moreover, shed more bacteria that readily infected other animals. These results imply an important evolutionary role for innate SAbs in protecting both the individual and the herd against infections, and suggest that the major role of SAbs may be to prevent the spread of microbial pathogens throughout the population, rather than protection of local mucosal surfaces.

  11. Factors influencing phagocytosis of Salmonella typhimurium by macrophages in murine schistosomiasis

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    Muniz-Junqueira Maria Imaculada

    1997-01-01

    Full Text Available We investigated the influence of Salmonella typhimurium load and specific antibodies on phagocytosis in schistosomiasis. Macrophages from Schistosoma mansoni-infected mice showed depressed capacity to increase the phagocytosis in the presence of a high bacterial load, due to a reduced involvement of these cells in phagocytosis and to a deficient ability to increase the number of phagocytosed bacteria. Normal and Salmonella-infected mice increased their phagocytic capacity when exposed to a high bacterial load. Antibody to Salmonella increased the phagocytic capacity of macrophages from Schistosoma-infected mice due to an increase in the number of bacteria phagocytosed but caused no modification in the number of macrophages engaged in phagocytosis. Our data indicate that macrophages from Schistosoma-infected mice work close to their functional limit, since no increase in phagocytosis was observed after increasing the bacterial load. Specific antibodies can improve their phagocytic capacity and, therefore, could help clearing concurrent infection.

  12. Rectal stenosis in pigs associated with Salmonella Typhimurium and porcine circovirus type 2 (PCV2 infection

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    Tatiane Terumi Negrão Watanabe

    2011-06-01

    Full Text Available Rectal stricture is an acquired annular fibrous constriction of the rectum that results from a variety of chronic necrotizing enteric diseases. In pigs, it is in most cases a sequel of Salmonella infection. Porcine circovirus type 2 (PCV2 is a known pathogen causing immunosuppression in pigs worldwide. PCV2 infected pigs may be predisposed to salmonellosis. In this report, rectal stenosis was observed in 160 pigs from a herd that experienced an outbreak of enteric salmonellosis over a 4-month period. Distension of the abdominal wall and diarrhea were the main clinical signs observed. Five animals were analyzed showing annular cicatrization of the rectal wall 5.0-7.0 cm anterior to the anorectal junction and Salmonella-positive immunostaining in the large intestine. Salmonella Typhimurium was isolated from fragments of the large intestine. Porcine circovirus type 2 antigen was observed in the mesenteric lymph-node in 4 pigs and in the large intestine in 3 pigs.

  13. Salmonella typhimurium infection in total knee arthroplasty: A case report with review of literature

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    Sujeesh Sebastian

    2017-01-01

    Full Text Available Salmonella enterica serotype Typhimurium is a rare cause of prosthetic joint infection (PJI. The recognized predisposing risk factors for Salmonella septic arthritis include diabetes mellitus, renal failure, human immunodeficiency virus infection and chronic corticosteroid use. We describe a case of PJI of the knee in a 74-year-old lady who was on antitubercular treatment. The patient presented with discharging sinus and raised inflammatory markers. She was successfully treated by the removal of prosthesis and debridement followed by ciprofloxacin therapy for 6 weeks. This case report highlights the potential virulence of Salmonella in immunocompromised patient with a joint prosthesis. Continuous monitoring and close collaboration of microbiologists and orthopedicians helped obtain the resolution of infection in our patient.

  14. Control of Salmonella enterica Typhimurium in chicken breast meat by irradiation combined with modified atmosphere packaging.

    Science.gov (United States)

    Kudra, L L; Sebranek, J G; Dickson, J S; Mendonca, A F; Zhang, Q; Jackson-Davis, A; Prusa, K J

    2011-11-01

    Salmonella is one of the leading causes of human foodborne illnesses originating from meat and poultry products. Cross-contamination of Salmonella from raw to cooked products continues to be problematic in the food industry. Therefore, new intervention strategies are needed for meat and poultry products. Vacuum or modified atmosphere packaging (MAP) are common packaging techniques used to extend the shelf life of meat products. Irradiation has been well established as an antibacterial treatment to reduce pathogens on meat and poultry. Combining irradiation with high-CO(2)+CO MAP was investigated in this study for improving the control of Salmonella enterica Typhimurium on chicken breast meat. The radiation sensitivities (D10-values) of this pathogen in chicken breast meat were found to be similar in vacuum and in high-CO(2)+CO MAP (0.55 ± 0.03 kGy and 0.54 ± 0.03 kGy, respectively). Irradiation at 1.5 kGy reduced the Salmonella population by an average of 3 log. Some Salmonella cells survived in both vacuum and high-CO(2) + CO MAP through 6 weeks of refrigerated storage following irradiation. This pathogen also grew in both vacuum and MAP when the product was held at 25°C. This study demonstrated that irradiation is an effective means of reducing Salmonella on meat or poultry, but packaging in either vacuum or MAP had little impact during subsequent refrigerated storage.

  15. Protective immunity conferred by a DNA adenine methylase deficient Salmonella enterica serovar Typhimurium vaccine when delivered in-water to sheep challenged with Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Mohler, V L; Heithoff, D M; Mahan, M J; Walker, K H; Hornitzky, M A; Gabor, L; Thomson, P C; Thompson, A; House, J K

    2011-04-27

    Stimulation of acquired immunity to Salmonella in livestock is not feasible in neonates (which can be infected within 24h of birth) and is challenging in feedlots, which typically source animals from diverse locations and vendors. Induction of innate immune mechanisms through mass vaccination of animals upon arrival to feedlots is an alternative approach. Transport, environmental conditions, changes in social grouping, and further handling during feedlot assembly are significant stressors. These factors, as well as concurrent exposure to a diversity of pathogens, contribute to the risk of disease. We have shown that oral immunization of calves with a modified live Salmonella enterica serovar Typhimurium vaccine strain, which lacks the DNA adenine methylase gene (S. Typhimurium dam), attenuates the severity of clinical disease, reduces fecal shedding, and promotes clearance of salmonellae following virulent homologous and heterologous challenge. This study examines the safety and efficacy of a S. Typhimurium dam vaccine in sheep via oral delivery in drinking water (ad libitum), as a means to effectively vaccinate large groups of animals. Adult merino sheep were vaccinated in drinking water -28 days, -7 days and 24h pre and 24h post-virulent Salmonella Typhimurium challenge which was administered via the oral route. Significant attenuation of clinical disease (temperature, appetite, and attitude) and reduction in mortality and virulent Salmonella Typhimurium fecal shedding and tissue colonization was observed in animals that received the vaccine 28 and 7 days pre-challenge. Further, vaccination did not pose a risk to stock previously infected with virulent salmonellae as mortalities and clinical disease in sheep vaccinated prior to or following virulent challenge did not differ significantly from the non-vaccinated controls. The capacity of S. Typhimurium dam vaccines delivered in drinking water to protect livestock from virulent Salmonella challenge offers an

  16. Global regulation by CsrA in Salmonella typhimurium.

    Science.gov (United States)

    Lawhon, Sara D; Frye, Jonathan G; Suyemoto, Mitsu; Porwollik, Steffen; McClelland, Michael; Altier, Craig

    2003-06-01

    CsrA is a regulator of invasion genes in Salmonella enterica serovar Typhimurium. To investigate the wider role of CsrA in gene regulation, we compared the expression of Salmonella genes in a csrA mutant with those in the wild type using a DNA microarray. As expected, we found that expression of Salmonella pathogenicity island 1 (SPI-1) invasion genes was greatly reduced in the csrA mutant, as were genes outside the island that encode proteins translocated into eukaryotic cells by the SPI-1 type III secretion apparatus. The flagellar synthesis operons, flg and fli, were also poorly expressed, and the csrA mutant was aflagellate and non-motile. The genes of two metabolic pathways likely to be used by Salmonella in the intestinal milieu also showed reduced expression: the pdu operon for utilization of 1,2-propanediol and the eut operon for ethanolamine catabolism. Reduced expression of reporter fusions in these two operons confirmed the microarray data. Moreover, csrA was found to regulate co-ordinately the cob operon for synthesis of vitamin B12, required for the metabolism of either 1,2-propanediol or ethanolamine. Additionally, the csrA mutant poorly expressed the genes of the mal operon, required for transport and use of maltose and maltodextrins, and had reduced amounts of maltoporin, normally a dominant protein of the outer membrane. These results show that csrA controls a number of gene classes in addition to those required for invasion, some of them unique to Salmonella, and suggests a co-ordinated bacterial response to conditions that exist at the site of bacterial invasion, the intestinal tract of a host animal.

  17. Survival of Salmonella eastbourne and Salmonella typhimurium in milk chocolate prepared with artificially contaminated milk powder.

    Science.gov (United States)

    Tamminga, S K; Beumer, R R; Kampelmacher, E H; van Leusden, F M

    1977-12-01

    Milk chocolate mass containing salmonellas was prepared by mixing artificially contaminated milk powder with the other ingredients at a temperature of about 40 degrees C. From this mass bars were made. Two series were prepared, with S. eastbourne and S. typhimurium respectively. The number of surviving salmonellas was counted after various periods of storage, up to 19 months. S. eastbourne was reduced in numbers during 19 months from an initial count of ca. 3 x 10(4) to ca. 3 x 10(2) per 100 g of chocolate. S. typhimurium died off more rapidly, and was not detectable in about 55 g after 15 months, in spite of an initial count of ca. 10(5) per 100 g.In these experiments the salmonellas in the milk powder had had to survive the spraying procedure and the adverse conditions in the dried powder. This may be the reason why S. eastbourne showed a distinctly better survival on storage than the same serotype showed in previous experiments in which the organism was added as a broth culture to the chocolate mix. With S. typhimurium, however, such a difference was hardly detectable.Possible explanations of these results are discussed.

  18. Production of Diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011

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    Shiva Kumar Vasanth V

    2002-03-01

    Full Text Available Abstract Background Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP. DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP. Results S. typhimurium PU011, a non-virulent bacterial strain isolated in our lab, was found to produce DAP ammonia lyase enzyme when grown in minimal medium containing DAP. There was a direct correlation between biomass yield and enzyme activity, until 16 h post inoculation in minimal medium containing DAP. Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained. The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C. The Km value for the substrate was found to be 0.685mM, calculated from a Line Weaver Burk plot. Conclusion A new bacterial strain, S.typhimurium PU 011, which is capable of producing DAP ammonia lyase, was isolated.

  19. Effect of egg washing and correlation between eggshell characteristics and egg penetration by various Salmonella Typhimurium strains.

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    Vaibhav C Gole

    Full Text Available Salmonella is an important foodborne pathogen, causing an estimated 11,992 cases of infection in Australia per year. Egg or egg product related salmonellosis is a major concern for the egg industry. Worldwide, S. Typhimurium is one of the most common serovars identified in Salmonella food poisoning cases. The current study investigated the ability of five S. Typhimurium strains to penetrate washed and unwashed eggs using whole egg and agar egg penetration methods. All S. Typhimurium strains were able to penetrate eggshells and survive in egg albumen (at 20°C according to whole egg penetration results. Polymerase Chain Reaction results demonstrated that S. Typhimurium strain 2 (10(3 and 10(5 CFU/mL, and strain 5 (10(3 and 10(5 CFU/mL egg penetration was significantly higher (p<0.05 in washed eggs when compared to unwashed eggs. Statistical analysis of the agar penetration experiment indicated that S. Typhimurium was able to penetrate washed eggs at a significantly higher rate when compared to unwashed eggs (p<0.05. When compared to unwashed eggs, washed eggs also had significantly damaged cuticles. Statistical analysis also indicated that eggshell penetration by S. Typhimurium was related to various eggshell ultrastructural features such as cap quality, alignment, erosion, confluence, Type B bodies and cuticle cover.

  20. Lactobacillus bulgaricus, Lactobacillus rhamnosus and Lactobacillus paracasei Attenuate Salmonella Enteritidis, Salmonella Heidelberg and Salmonella Typhimurium Colonization and Virulence Gene Expression In Vitro

    OpenAIRE

    Muyyarikkandy, Muhammed Shafeekh; Amalaradjou, Mary Anne

    2017-01-01

    Salmonella Enteritidis (SE), Salmonella Typhimurium (ST), and Salmonella Heidelberg (SH) have been responsible for numerous outbreaks associated with the consumption of poultry meat and eggs. Salmonella colonization in chicken is characterized by initial attachment to the cecal epithelial cells (CEC) followed by dissemination to the liver, spleen, and oviduct. Since cecal colonization is critical to Salmonella transmission along the food chain continuum, reducing this intestinal association c...

  1. Establishment of a pathogenicity index in Salmonella Enteritidis and Salmonella Typhimurium strains inoculated in one-day-old broiler chicks

    Directory of Open Access Journals (Sweden)

    D.A. Lima

    2016-04-01

    Full Text Available Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and presence of lesions such as aerosaculitis (A, perihepatitis (Ph, pericarditis (Pc, peritonitis (Pt, onfalitis (O and cellulitis (C were registered daily for seven days. From the second to the seventh day there was a proportional decrease in the punctuation of the time of death (TD for each day that the bird had survived. The pathogenicity index was calculated using the following formula: PI = (TD x 5 + A + Ph + Pc + Pt + O + C. The obtainment of the PI of each bacterial sample was achieved by calculating the rate of the ten inoculated birds. Based on the obtained results, it was possible to attribute the pathogenicity value for each strain, which enabled us to classify them in groups of low (27/200, intermediate (95/200 and high (78/200 pathogenicity. The utilization of standards like time of death and presence of septicemic lesions made it possible to determine the pathogenicity rate for each strain. Besides that, the proposed model has presented dramatic differences between the high, intermediate and low pathogenicity groups, which makes this mechanism useful for further classification of strains isolated in poultry farms.

  2. Affinity-Selected Filamentous Bacteriophage as a Probe for Acoustic Wave Biodetectors of Salmonella typhimurium

    National Research Council Canada - National Science Library

    Olsen, Eric V; Sorokulova, Iryna B; Petrenko, Valery A; Chen, I-Hsuan; Barbaree, James M; Vodyanoy, Vitaly J

    2005-01-01

    Proof-in-concept biosensors were prepared for the rapid detection of Salmonella typhimurium in solution, based on affinity-selected filamentous phage prepared as probes physically adsorbed to piezoelectric transducers...

  3. Competitive Survival of Escherichia coli, Vibrio cholerae, Salmonella typhimurium and Shigella dysenteriae in Riverbed Sediments

    CSIR Research Space (South Africa)

    Abia, AL

    2016-11-01

    Full Text Available investigated the survival of Escherichia coli, Salmonella enterica ser. Typhimurium, Vibrio cholerae and Shigella dysenteriae in riverbed sediments of the Apies River. Experiments were performed in flow chambers containing three sediment types and connected...

  4. Fate of Salmonella Typhimurium in laboratory-scale drinking water biofilms

    CSIR Research Space (South Africa)

    Schaefer, Lisa M

    2013-08-01

    Full Text Available Investigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein...

  5. Survival and transmission of Salmonella enterica serovar Typhimurium in an outdoor organic pig farming environment

    OpenAIRE

    Jensen, A.N.; Dalsgaard, A.; Stockmarr, A.; Nielsen, E.M.; Baggesen, D.L.

    2006-01-01

    It was investigated how organic rearing conditions influence the Salmonella enterica infection dynamics in pigs and whether Salmonella persists in the paddock environment. Pigs inoculated with S. enterica serovar Typhimurium were grouped with Salmonella-negative tracer pigs. Bacteriological and serological testing indicated that organic pigs were susceptible to Salmonella infections, as 26 of 46 (56%) tracer pigs turned culture positive. An intermittent and mainly low-level excretion of Sa...

  6. Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes

    Science.gov (United States)

    The objectives of the present study were to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three mutants on the smoo...

  7. A mixture containing galactooligosaccharide, produced by the enzymic activity of Bifidobacterium bifidum, reduces Salmonella enterica serovar Typhimurium infection in mice.

    Science.gov (United States)

    Searle, Laura E J; Best, Angus; Nunez, Alejandro; Salguero, Francisco J; Johnson, Linda; Weyer, Ute; Dugdale, Alexandra H; Cooley, William A; Carter, Ben; Jones, Gareth; Tzortzis, George; Woodward, Martin J; La Ragione, Roberto M

    2009-01-01

    The prebiotic Bimuno is a mixture containing galactooligosaccharide, produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 41171 in the presence of lactose. Previous studies have implicated prebiotics in reducing infections by enteric pathogens, thus it was hypothesized that Bimuno may confer some protection in the murine host from Salmonella enterica serovar Typhimurium (S. Typhimurium) infection. In this study, infection caused by S. Typhimurium SL1344nal(r) in the presence or absence of Bimuno was assessed using tissue culture assays, a murine ligated ileal gut loop model and a murine oral challenge model. In tissue culture adherence and invasion assays with HT-29-16E cells, the presence of approximately 2 mM Bimuno significantly reduced the invasion of S. Typhimurium SL1344nal(r) (PBimuno prevented colonization and the associated pathology of S. Typhimurium. In the BALB/c mouse model, the oral delivery of Bimuno prior to challenge with S. Typhimurium resulted in significant reductions in colonization in the five organs sampled, with highly significant reductions being observed in the spleen at 72 and 96 h post-challenge (P=0.0002, Bimuno significantly reduced the colonization and pathology associated with S. Typhimurium infection in a murine model system, possibly by reducing the invasion of the pathogen into host cells.

  8. Impact of Hfq on the intrinsic drug resistance of Salmonella enterica serovar Typhimurium

    Directory of Open Access Journals (Sweden)

    Mitsuko eHayashi-Nishino

    2012-06-01

    Full Text Available Salmonella enterica is an important enteric pathogen, and its various serovars cause both systemic and intestinal diseases in humans and domestic animals. The emergence of multidrug-resistant strains of Salmonella, leading to increased morbidity and mortality, has further complicated its management. Hfq is an RNA chaperon that mediates the binding of small RNAs to mRNA and assists in post-transcriptional gene regulation in bacteria. Although Hfq is related to important phenotypes including virulence in Salmonella, its role in the drug resistance of this organism is unknown. The aim of this study was to investigate the role of Hfq in intrinsic drug resistance of S. enterica serovar Typhimurium. hfq mutant was susceptible to acriflavine. Although there is a relationship between the production of the AcrB multidrug efflux pump and Hfq in Escherichia coli, the deletion of the drug efflux acrB did not impair the effect of hfq deletion on Salmonella susceptibility. In contrast, the deletion of another drug efflux gene, smvA, impaired the effect of hfq deletion on acriflavine susceptibility. These results indicate that Hfq regulates the intrinsic drug resistance, and it may influence drug susceptibility by regulating SmvA in Salmonella.

  9. Chlorine inactivation of nonresistant and antibiotic-resistant strains of salmonella typhimurium isolated from chicken carcasses.

    Science.gov (United States)

    Oscar, T P; Tasmin, R; Parveen, S

    2013-06-01

    A study was conducted to test the hypothesis that strains of Salmonella Typhimurium that are resistant to antibiotics are more resistant to chlorine in chilled water than strains of Salmonella Typhimurium that are not resistant to antibiotics. To test this hypothesis, strains (n = 16) of Salmonella Typhimurium with four antibiotic resistance profiles were tested for their inactivation kinetics in chlorinated (30 ppm, pH 6) water at 4°C. The four antibiotic resistance profiles were (i) none; (ii) tetracycline-sulfisoxazole (T-Su); (iii) tetracycline-ampicillin-amoxicillin-cefoxitin-ceftiofur-sulfisoxazole (T-A-Am-C-Ce-Su); and (iv) tetracycline-ampicillin-amoxicillin-cefoxitin-ceftiofur-sulfisoxazole-kanamycin (T-A-Am-C-Ce-Su-K). Inactivation of Salmonella Typhimurium in chlorinated water displayed nonlinear kinetics with a concave downward curve that fit well (R(2) = 0.964) to the power law model, with a shape parameter of 1.37. The time for a single log reduction (D-value) of Salmonella Typhimurium from an initial concentration of 5.36 log/ml did not differ (P > 0.05) among the four antibiotic resistance groups and ranged from 3.8 to 4.3 min for n = 4 strains per group. Thus, the hypothesis was rejected, and it was concluded that expression of an antibiotic resistance phenotype does not confer cross-protection in Salmonella Typhimurium to chlorine inactivation in chilled water.

  10. A comparison between longitudinal shedding patterns of Salmonella Typhimurium and Salmonella Dublin on dairy farms.

    Science.gov (United States)

    Kirchner, M; McLaren, I; Clifton-Hadley, F A; Liebana, E; Wales, A D; Davies, R H

    2012-08-25

    Salmonella in cattle herds may behave as epidemic or endemic infections. An intensive longitudinal sampling study across all management groups and ages on six dairy farms in the UK was used to examine patterns of Salmonella shedding, following the prior identification of either Salmonella Dublin (SD) (three farms) or Salmonella Typhimurium (ST) (three farms) on the premises in the context of clinical salmonellosis. Individual faeces, pooled faeces and environmental samples (total 5711 samples), taken approximately every six weeks for 15-24 weeks, were cultured for Salmonella. SD was detected at low frequency (on any visit, 0.5-18.3 per cent of samples positive) and most consistently in calves. By contrast, ST was isolated at higher frequency (on any visit, 6.8-75 per cent of samples positive), and in higher numbers, up to 10(7) cfu/g faeces. Significantly more samples from calves were positive for ST than were positive for SD (50.6 per cent v 3.1 per cent; P < 0.001), which was also true for milking cows (46.3 per cent v 4.4 per cent; P < 0.001). The differences could help to explain the different patterns of bovine infection classically associated with these two serovars in the UK. No consistent effect upon shedding was seen among the ST-infected herds following vaccination.

  11. Molecular characterization of "inconsistent" variants of Salmonella Typhimurium isolated in Italy

    DEFF Research Database (Denmark)

    Barco, Lisa; Longo, Alessandra; Lettini, Antonia Anna

    2014-01-01

    Salmonella 4,[5],12:i:- is a variant of Salmonella Typhimurium, which lacks the expression of phase-2 flagellar antigen, generally associated with the deletion of the fljB gene. Additional mechanisms involving the fljAB operon ( fljA, fljB, and hin genes) lead to the lack of expression of phase-2...

  12. Multistate Outbreak of Human Salmonella Typhimurium Infections Linked to Pet Hedgehogs - United States, 2011-2013.

    Science.gov (United States)

    Anderson, T C; Marsden-Haug, N; Morris, J F; Culpepper, W; Bessette, N; Adams, J K; Bidol, S; Meyer, S; Schmitz, J; Erdman, M M; Gomez, T M; Barton Behravesh, C

    2017-06-01

    Zoonotic Salmonella infections cause approximately 130 000 illnesses annually in the United States. Of 72.9 million US households owning at least one pet, five million own small mammals; 3000 hedgehogs were documented by USDA in USDA-licensed breeding facilities and pet stores in 2012. State health department collaborators and PulseNet, the national bacterial subtyping network, identified human infections of a Salmonella Typhimurium outbreak strain, which were investigated by CDC, USDA-APHIS and state public and animal health officials. A case was defined as an illness in a person infected with the outbreak strain identified between 1 December 2011 and 3 June 2013. Investigators collected information on patient exposures, cultured animal and environmental specimens for Salmonella, and conducted traceback investigations of USDA-licensed hedgehog facilities. There were 26 cases in 12 states. Illness onset dates ranged from 26 December 2011 to 8 April 2013. The median patient age was 15 years (range = pet hedgehog contact in the week before illness onset. The outbreak strain was isolated from animal and environmental samples collected from three ill persons' homes in three states. Hedgehogs were purchased in geographically distant states from USDA-licensed breeders (10/17, 59%); a USDA-licensed pet store (1/17, 6%); unlicensed or unknown status breeders (3/17, 18%); and private individuals (3/17, 18%). Traceback investigations of USDA-licensed facilities did not reveal a single source of infection. Public and animal health collaboration linked pet hedgehog contact to human infections of Salmonella Typhimurium, highlighting the importance of a One Health investigative approach to zoonotic salmonellosis outbreaks. More efforts are needed to increase awareness among multiple stakeholders on the risk of illness associated with pet hedgehogs. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  13. Inactivation of Salmonella Senftenberg, Salmonella Typhimurium and Salmonella Tennessee in peanut butter by 915 MHz microwave heating.

    Science.gov (United States)

    Song, Won-Jae; Kang, Dong-Hyun

    2016-02-01

    This study evaluated the efficacy of a 915 MHz microwave with 3 different levels to inactivate 3 serovars of Salmonella in peanut butter. Peanut butter inoculated with Salmonella enterica serovar Senftenberg, S. enterica serovar Typhimurium and S. enterica serovar Tennessee were treated with a 915 MHz microwave with 2, 4 and 6 kW and acid and peroxide values and color changes were determined after 5 min of microwave heating. Salmonella populations were reduced with increasing treatment time and treatment power. Six kW 915 MHz microwave treatment for 5 min reduced these three Salmonella serovars by 3.24-4.26 log CFU/g. Four and two kW 915 MHz microwave processing for 5 min reduced these Salmonella serovars by 1.14-1.48 and 0.15-0.42 log CFU/g, respectively. Microwave treatment did not affect acid, peroxide, or color values of peanut butter. These results demonstrate that 915 MHz microwave processing can be used as a control method for reducing Salmonella in peanut butter without producing quality deterioration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Salmonella enterica serovar Typhimurium in Mauritius linked to consumption of marlin mousse.

    Science.gov (United States)

    Issack, Mohammad I; Hendriksen, Rene S; Lun, Phimy Lan Keng; Lutchun, Ram K S; Aarestrup, Frank M

    2009-01-01

    We report the first outbreak of salmonellosis caused by consumption of contaminated marlin mousse. Between 29 October and 5 November 2008, at least 53 persons developed diarrheal illness, all with a history of eating marlin mousse. Salmonella spp. that did not produce gas from glucose was isolated from stools of 26 affected patients and blood culture from one patient. Salmonella sp. isolates with the same phenotype were isolated in three samples of marlin mousse manufactured on 27 October 2008. The constituents of the mousse were smoked marlin, raw eggs, bovine gelatin, oil, and cream. A laboratory investigation of one sample of marlin mousse manufactured 3 days later, and the individual ingredients sampled a week after production of the contaminated batch were all negative for Salmonella. Serotyping and minimum inhibitory concentration determination were performed on 12 patient isolates related to the outbreak and two mousse isolates. All isolates belonged to Salmonella serovar Typhimurium and were pansusceptible to all antimicrobials tested. Pulsed-field gel electrophoresis revealed that all the isolates were indistinguishable, thus implicating the mousse as the vehicle of the outbreak.

  15. Evaluating Chemical Mitigation of Salmonella Typhimurium ATCC 14028 in Animal Feed Ingredients.

    Science.gov (United States)

    Cochrane, Roger A; Huss, Anne R; Aldrich, Gregory C; Stark, Charles R; Jones, Cassandra K

    2016-04-01

    Salmonella Typhimurium is a potential feed safety hazard in animal feed ingredients. Thermal mitigation of Salmonella spp. during rendering is effective but does not eliminate the potential for cross-contamination. Therefore, the objective of this experiment was to evaluate the effectiveness of chemicals to mitigate postrendering Salmonella Typhimurium ATCC 14028 contamination in rendered proteins over time. Treatments were arranged in a 6 × 4 factorial with six chemical treatments and four rendered protein meals. The chemical treatments included (i) control without chemical treatment, (ii) 0.3% commercial formaldehyde product, (iii) 2% essential oil blend, (iv) 2% medium chain fatty acid blend, (v) 3% organic acid blend, and (vi) 1% sodium bisulfate. The four rendered protein meals included (i) feather meal, (ii) blood meal, (iii) meat and bone meal, and (iv) poultry by-product meal. After matrices were chemically treated, they were inoculated with Salmonella Typhimurium ATCC 14028, stored at room temperature, and enumerated via plate counts on days 0, 1, 3, 7, 14, 21, and 42 postinoculation. The Salmonella concentration in ingredients treated with medium chain fatty acid and commercial formaldehyde were similar to one another (P = 0.23) but were 2 log lower than the control (P Salmonella concentrations than the control (P Salmonella mitigation, because all days except days 14 and 21 (P = 0.92) differed from one another. Rendered protein matrix also affected Salmonella stability, because concentrations in meat and bone meal and blood meal were similar to one another (P = 0.36) but were greater than levels in feather meal and poultry by-product meal (P Salmonella Typhimurium ATCC 14028, but their effectiveness was matrix dependent. Time and chemical treatment with medium chain fatty acids or a commercial formaldehyde product were most effective at mitigating Salmonella Typhimurium ATCC 14028 in rendered protein meals.

  16. Probiotic Bacteria Reduce Salmonella Typhimurium Intestinal Colonization by Competing for Iron

    Science.gov (United States)

    Deriu, Elisa; Liu, Janet Z.; Pezeshki, Milad; Edwards, Robert A.; Ochoa, Roxanna J.; Contreras, Heidi; Libby, Stephen J.; Fang, Ferric C.; Raffatellu, Manuela

    2013-01-01

    Summary Host inflammation alters the availability of nutrients such as iron to limit microbial growth. However, Salmonella enterica serovar Typhimurium thrives in the inflamed gut by scavenging for iron with siderophores. By administering Escherichia coli strain Nissle 1917, which assimilates iron by similar mechanisms, we show that this non-pathogenic bacterium can outcompete and reduce S. Typhimurium colonization in mouse models of acute colitis and chronic persistent infection. This probiotic activity depends on E. coli Nissle iron acquisition as mutants deficient in iron uptake colonize the intestine but do not reduce S. Typhimurium colonization. Additionally, the ability of E. coli Nissle to overcome iron restriction by the host protein lipocalin-2, which counteracts some siderophores, is essential as S. Typhimurium is unaffected by E. coli Nissle in lipocalin-2-deficient mice. Thus, iron availability impacts S. Typhimurium growth and E. coli Nissle reduces S. Typhimurium intestinal colonization by competing for this limiting nutrient. PMID:23870311

  17. Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium.

    Science.gov (United States)

    Yun, Ou; Zeng, Xin-An; Brennan, Charles S; Han, Zhong

    2016-08-22

    Salmonella typhimurium cells were subjected to pulsed electric field (PEF) treatment at 25 kV/cm for 0-4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi), possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression), which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids). In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC) indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms.

  18. Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium

    Directory of Open Access Journals (Sweden)

    Ou Yun

    2016-08-01

    Full Text Available Salmonella typhimurium cells were subjected to pulsed electric field (PEF treatment at 25 kV/cm for 0–4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi, possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression, which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids. In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms.

  19. Identification of Potential Therapeutics to Conquer Drug Resistance in Salmonella typhimurium: Drug Repurposing Strategy.

    Science.gov (United States)

    Preethi, Balasundaram; Shanthi, Veerappapillai; Ramanathan, Karuppasamy

    2016-12-01

    Salmonella typhimurium is the main cause of gastrointestinal illness in humans, and treatment options are decreasing because drug-resistant strains have emerged. The objective of this study was to use computational drug repurposing to identify a novel candidate with an effective mechanism of action to circumvent the drug resistance. We used the Mantra 2.0 database to initially screen drug candidates that share similar gene expression profiles to those of quinolones. Data were further reduced using pharmacophore mapping theory. Finally, we employed molecular-simulation studies to calculate the binding affinity of the screened candidates with DNA gyrase, alongside an analysis of side effects. A total of 16 drug candidates from the Mantra 2.0 database were screened. The pharmacophoric features of the screened candidates were examined and nalidixic acid features compared using the PharamGist program. A total of 11 compounds with the highest pharmacophore score were considered for binding energy calculation. Finally, we analysed the side effects of the eight drug candidates that showed significant binding affinity in the simulation study. Overall, flufenamic acid and sulconazole may be potential drug candidates that could be studied in vitro to assess their resistance profile against Salmonella enterica Typhimurium.

  20. Branched-chain amino acid supplementation promotes aerobic growth of Salmonella Typhimurium under nitrosative stress conditions.

    Science.gov (United States)

    Park, Yoon Mee; Lee, Hwa Jeong; Jeong, Jae-Ho; Kook, Joong-Ki; Choy, Hyon E; Hahn, Tae-Wook; Bang, Iel Soo

    2015-12-01

    Nitric oxide (NO) inactivates iron-sulfur enzymes in bacterial amino acid biosynthetic pathways, causing amino acid auxotrophy. We demonstrate that exogenous supplementation with branched-chain amino acids (BCAA) can restore the NO resistance of hmp mutant Salmonella Typhimurium lacking principal NO-metabolizing enzyme flavohemoglobin, and of mutants further lacking iron-sulfur enzymes dihydroxy-acid dehydratase (IlvD) and isopropylmalate isomerase (LeuCD) that are essential for BCAA biosynthesis, in an oxygen-dependent manner. BCAA supplementation did not affect the NO consumption rate of S. Typhimurium, suggesting the BCAA-promoted NO resistance independent of NO metabolism. BCAA supplementation also induced intracellular survival of ilvD and leuCD mutants at wild-type levels inside RAW 264.7 macrophages that produce constant amounts of NO regardless of varied supplemental BCAA concentrations. Our results suggest that the NO-induced BCAA auxotrophy of Salmonella, due to inactivation of iron-sulfur enzymes for BCAA biosynthesis, could be rescued by bacterial taking up exogenous BCAA available in oxic environments.

  1. A comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice

    Directory of Open Access Journals (Sweden)

    Bogomolnaya Lydia M

    2008-10-01

    Full Text Available Abstract Background Salmonellosis is one of the most important bacterial food borne illnesses worldwide. A major source of infection for humans is consumption of chicken or egg products that have been contaminated with Salmonella enterica serotype Typhimurium, however our knowledge regarding colonization and persistence factors in the chicken is small. Results We compared intestinal and systemic colonization of 1-week-old White Leghorn chicks and Salmonella-resistant CBA/J mice during infection with Salmonella enterica serotype Typhimurium ATCC14028, one of the most commonly studied isolates. We also studied the distribution of wild type serotype Typhimurium ATCC14028 and an isogenic invA mutant during competitive infection in the cecum of 1-week-old White Leghorn chicks and 8-week-old CBA/J mice. We found that although the systemic levels of serotype Typhimurium in both infected animal models are low, infected mice have significant splenomegaly beginning at 15 days post infection. In the intestinal tract itself, the cecal contents are the major site for recovery of serotype Typhimurium in the cecum of 1-week-old chicks and Salmonella-resistant mice. Additionally we show that only a small minority of Salmonellae are intracellular in the cecal epithelium of both infected animal models, and while SPI-1 is important for successful infection in the murine model, it is important for association with the cecal epithelium of 1-week-old chicks. Finally, we show that in chicks infected with serotype Typhimurium at 1 week of age, the level of fecal shedding of this organism does not reflect the level of cecal colonization as it does in murine models. Conclusion In our study, we highlight important differences in systemic and intestinal colonization levels between chick and murine serotype Typhimurium infections, and provide evidence that suggests that the role of SPI-1 may not be the same during colonization of both animal models.

  2. Ultraviolet (UV-C inactivation of Enterococcus faecium, Salmonella choleraesuis and Salmonella typhimurium in porcine plasma.

    Directory of Open Access Journals (Sweden)

    Elena Blázquez

    Full Text Available The objective of this study was to assess the effectiveness of an ultraviolet (UV-C, 254 nm irradiation system on reducing the load of Salmonella typhimurium (S. typhimurium, Salmonella choleraesuis (S. choleraesuis resistant to streptomycin and Enterococcus faecium (E. faecium inoculated in sterile porcine plasma and then subjected to different UV-C irradiation doses (750, 1500, 3000, 6000 and 9000 J/L using a pilot plant UV-C device working under turbulent flow. Results indicated that UV-C treatment induced a viability reduction of 0.38, 1.18, 3.59, 4.72 and 5.06 log10 S. typhimurium when irradiated at 750, 1500, 3000, 6000 and 9000 J/L, respectively. The observed log10 reduction of S. choleraesuis was 1.44, 2.68, 5.55, 7.07 and 7.97 at 750, 1500, 3000, 6000 and 9000 J/L, respectively. The best-fit inactivation for S. choleraesuis was the Weibull distribution curve, while the best-fit curve for S. typhimurium was the Weibull plus tail model, indicating that around 102 cfu/mL resistant S. typhimurium was detected when the liquid plasma was UV-C irradiated at doses up to 9000 J/L. Viability reduction for E. faecium was 0.44, 1.01, 3.70, 5.61 and 6.22 log10 when irradiated at 750, 1500, 3000, 6000 and 9000 J/L, respectively, with no bacterial resistance observed with UV-C doses of 6000 J/L or higher. The biphasic model was the best fit model for the inactivation curve for E. faecium. For the three microorganisms tested, about a 4 log-unit reduction was achieved when the liquid plasma was irradiated at 3000J/L. Overall results demonstrate the usefulness of the UV-C system to inactivate bacteria in liquid plasma before spray-drying. We conclude that the UV-C system can provide an additional biosafety feature that can be incorporated into the manufacturing process for spray-dried animal plasma.

  3. Ultraviolet (UV-C) inactivation of Enterococcus faecium, Salmonella choleraesuis and Salmonella typhimurium in porcine plasma.

    Science.gov (United States)

    Blázquez, Elena; Rodríguez, Carmen; Ródenas, Jesús; Pérez de Rozas, Ana; Segalés, Joaquim; Pujols, Joan; Polo, Javier

    2017-01-01

    The objective of this study was to assess the effectiveness of an ultraviolet (UV-C, 254 nm) irradiation system on reducing the load of Salmonella typhimurium (S. typhimurium), Salmonella choleraesuis (S. choleraesuis) resistant to streptomycin and Enterococcus faecium (E. faecium) inoculated in sterile porcine plasma and then subjected to different UV-C irradiation doses (750, 1500, 3000, 6000 and 9000 J/L) using a pilot plant UV-C device working under turbulent flow. Results indicated that UV-C treatment induced a viability reduction of 0.38, 1.18, 3.59, 4.72 and 5.06 log10 S. typhimurium when irradiated at 750, 1500, 3000, 6000 and 9000 J/L, respectively. The observed log10 reduction of S. choleraesuis was 1.44, 2.68, 5.55, 7.07 and 7.97 at 750, 1500, 3000, 6000 and 9000 J/L, respectively. The best-fit inactivation for S. choleraesuis was the Weibull distribution curve, while the best-fit curve for S. typhimurium was the Weibull plus tail model, indicating that around 102 cfu/mL resistant S. typhimurium was detected when the liquid plasma was UV-C irradiated at doses up to 9000 J/L. Viability reduction for E. faecium was 0.44, 1.01, 3.70, 5.61 and 6.22 log10 when irradiated at 750, 1500, 3000, 6000 and 9000 J/L, respectively, with no bacterial resistance observed with UV-C doses of 6000 J/L or higher. The biphasic model was the best fit model for the inactivation curve for E. faecium. For the three microorganisms tested, about a 4 log-unit reduction was achieved when the liquid plasma was irradiated at 3000J/L. Overall results demonstrate the usefulness of the UV-C system to inactivate bacteria in liquid plasma before spray-drying. We conclude that the UV-C system can provide an additional biosafety feature that can be incorporated into the manufacturing process for spray-dried animal plasma.

  4. Nitroreductase from Salmonella typhimurium: characterization and catalytic activity.

    Science.gov (United States)

    Yanto, Yanto; Hall, Mélanie; Bommarius, Andreas S

    2010-04-21

    The biocatalytic activity of nitroreductase from Salmonella typhimurium (NRSal) was investigated for the reduction of alpha,beta-unsaturated carbonyl compounds, nitroalkenes, and nitroaromatics. The synthesized gene was subcloned into a pET28 overexpression system in E.coli BL21 strain, and the corresponding expressed protein was purified to homogeneity with 15% protein mass yield and 41% of total activity recovery. NRSal showed broad substrate acceptance for various nitro compounds such as 1-nitrocyclohexene and aliphatic nitroalkenes (alkene reductase activity), as well as nitrobenzene (nitroreductase activity), with substrate conversion efficiency of > 95%. However, the reduction of enones was generally low, proceeding albeit with high stereoselectivity. The efficient biocatalytic reduction of substituted nitroalkenes provides a route for the preparation of the corresponding nitroalkanes. NRSal also demonstrated the first single isolated enzyme-catalyzed reduction of nitrobenzene to aniline through the formation of nitrosobenzene and phenylhydroxylamine as intermediates. However, chemical condensation of the two intermediates to produce azoxybenzene currently limits the yield of aniline.

  5. Survival and transmission of Salmonella enterica serovar typhimurium in an outdoor organic pig farming environment

    DEFF Research Database (Denmark)

    Jensen, Annette Nygaard; Dalsgaard, Anders; Stockmarr, Anders

    2006-01-01

    showed that pigs reared under organic conditions were susceptible to Salmonella infections (just like conventional pigs) and that Salmonella persisting in the paddock environment could pose an infection risk. A driving force for these infections seemed to be pigs with a high Salmonella excretion level......It was investigated how organic rearing conditions influence the Salmonella enterica infection dynamics in pigs and whether Salmonella persists in the paddock environment. Pigs inoculated with S. enterica serovar Typhimurium were grouped with Salmonella-negative tracer pigs. Bacteriological...... and serological testing indicated that organic pigs were susceptible to Salmonella infections, as 26 of 46 (56%) tracer pigs turned culture positive. An intermittent and mainly low-level excretion of Salmonella (

  6. Growth and destruction of Salmonella typhimurium in egg white foam products cooked by microwaves.

    Science.gov (United States)

    Baldwin, R E; Cloninger, M; Fields, M L

    1968-12-01

    Currently, in both home and institutional food preparation, attempts are being made to produce high quality foods with a minimum of time and effort. Research is being carried out to develop equipment capable of cooking foods in a fraction of the time required by conventional methods; as a result, the problem arises as to the bacteriological safety of these products. We investigated the microbiological aspects of lemon and chocolate foam pies before and after cooking by microwaves for less than 2 min. Pies prepared with sterile equipment under sanitary conditions were inoculated with washed cells from a 24-hr broth culture of Salmonella typhimurium and were incubated for 24, 48, and 72 hr at 33 C. The same procedures were followed in model systems to determine the effects of various sugar and pH levels on the survival of S. typhimurium. No S. typhimurium was detected in inoculated cooked or uncooked lemon pies by the plating method; with the Lactose Broth pre-enrichment method, survivors were detected in lemon pies immediately after preparation. After electronic cooking, no survivors were detected in lemon pies by plate counts, whereas cells were recovered from chocolate pies by the Lactose Broth method. Both chocolate and lemon pies had lower counts throughout the 72-hr incubation period than the model systems compared to them. With the model systems, at pH 7.3, media containing sugar inhibited the growth of S. typhimurium but did not cause a significant reduction in counts during the incubation times studied. At pH 3.7, media without sugar yielded no cells with the Lactose Broth pre-enrichment method after 48 hr of incubation, whereas media with sugar were not sterile until after 72 hr of incubation. Apparently, the presence of sugar in the medium had a protective influence which made the lethal effect of the low pH less severe.

  7. Performance of broilers experimentally inoculated with Salmonella Typhimurium and fed diets with addition of lactulosis

    Directory of Open Access Journals (Sweden)

    Eliete Souza Santana

    2012-08-01

    Full Text Available The objective of this experiment was to evaluate the influence of lactulose on performance as well as its ability to prevent colonization by Salmonella Typhimurium in broilers orally inoculated with this pathogen. The design adopted was completely randomized, with 630 one-day-old male chicks distributed into six treatments, with seven replications and 15 birds per experimental unit. The treatments comprised the following procedures: T1 (control group - no S. Typhimurium inoculation or supply of lactulosis; T2 - only inoculation of S. Typhimurium; T3 - only lactulosis supply; T4 supply of lactulosis and S. Typhimurium inoculation on the first day of life; T5 - supply of lactulosis 48 hours before S. Typhimurium inoculation; and T6 - supply of lactulosis 48 hours after inoculation of S. Typhimurium. Performance variables were evaluated on the seventh, 14th, 21st and 28th days of age; fragments of the duodenum and jejunum were collected and sent to histomorphometric assessment at 14 days of age, and S. Typhimurium excretion was verified in cloacal swabs on the 10th, 24th and 35th days of age. Performance data were analyzed by ANOVA and Tukey's test (5% and fecal excretion data were assessed by non-parametric chi-square test. Better weight gain and feed conversion were observed in groups fed lactulosis with or without challenge of S. Typhimurium up to 21 days of age. Reduced duodenum villous height was verified on the 14th day in groups challenged with the pathogen. Reduction of S. Typhimurium fecal excretion was verified in broilers fed lactulosis from the first day of life on and 48 hours before receiving S. Typhimurium directly into the crop. Lactulosis increases broiler performance up to one week after its inoculation, influences duodenum villous height and reduces the fecal excretion of Salmonella Typhimurium.

  8. Comparison of sporadic cases of Salmonella Typhimurium with other Salmonella serotypes in Castellon (Spain): case-case study.

    Science.gov (United States)

    Arnedo-Pena, Alberto; Vivas-Fornas, Iraya; Meseguer-Ferrer, Noemi; Tirado-Balaguer, María Dolores; Yagüe-Muñoz, Alberto; Herrera-León, Silvia; Sabater-Vidal, Susana; Romeu-García, María Ángeles; Vizcaino Batllés, Ana; Bellido-Blasco, Juan Bautista; Moreno-Muñoz, Rosario

    2017-10-07

    Salmonella infections (SI) are common in Spain. The aim of this study was to appraise risk factors and the clinical characteristics of sporadic Salmonella Typhimurium infections compared with other sporadic salmonella serotype infections (OSI). From September 2014 to August 2015, a case-case study was carried out by the Epidemiology Division of the Public Health Centre of Castellon. Case 1 consisted of patients with sporadic S. Typhimurium infections, while case 2 comprised OSI patients, assessed according to the stool cultures analyzed by the Microbiology Laboratories of Hospital General de Castellon and Hospital de La Plana in Vila-real. Patients from detected outbreaks were not included. The salmonella serotype was identified by the National Centre of Microbiology (Madrid). The total number of SI patients reported was 327, 242 of whom were studied (74.0%). 148 patients had sporadic S. Typhimurium infection and 64 had OSI, with median ages of 4 and 8.5 years, respectively. Sporadic S. Typhimurium infection patients presented more blood in feces and diarrhea episodes. Consumption of pork meat (OR=2.22; 95% CI 1.12-4.43), cold pork meats (OR=2.49; 95% CI 1.32-4.68) and playing in the dirt (OR=3.02; 95% CI 1.55-5.88), were associated with sporadic S. Typhimurium infection. In the 0-4 year-old group, the associated factors were consumption of cold pork meats, omelets and female gender. In the 5-year-old and over group, only playing in soil was associated with sporadic S. Typhimurium infection. The consumption of pork and omelets, as well as playing in the dirt, were the main factors associated with infection. Children were most affected by sporadic S. Typhimurium infection. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  9. Salmonella enterica serovars Typhimurium and Typhi as model organisms

    Science.gov (United States)

    Garai, Preeti; Gnanadhas, Divya Prakash; Chakravortty, Dipshikha

    2012-01-01

    The lifestyle of intracellular pathogens has always questioned the skill of a microbiologist in the context of finding the permanent cure to the diseases caused by them. The best tool utilized by these pathogens is their ability to reside inside the host cell, which enables them to easily bypass the humoral immunity of the host, such as the complement system. They further escape from the intracellular immunity, such as lysosome and inflammasome, mostly by forming a protective vacuole-bound niche derived from the host itself. Some of the most dreadful diseases are caused by these vacuolar pathogens, for example, tuberculosis by Mycobacterium or typhoid fever by Salmonella. To deal with such successful pathogens therapeutically, the knowledge of a host-pathogen interaction system becomes primarily essential, which further depends on the use of a model system. A well characterized pathogen, namely Salmonella, suits the role of a model for this purpose, which can infect a wide array of hosts causing a variety of diseases. This review focuses on various such aspects of research on Salmonella which are useful for studying the pathogenesis of other intracellular pathogens. PMID:22722237

  10. Experimental Salmonella typhimurium infections in rats. III. Transfer of immunity with primed lymphocyte subpopulations

    DEFF Research Database (Denmark)

    Hougen, H P; Jensen, E T

    1990-01-01

    The protective effect of primed lymphocytes against a lethal dose of Salmonella typhimurium was studied in athymic and euthymic LEW rats. Primed lymphocytes were obtained by inoculating euthymic and thymus-grafted animals with a non-lethal dose of Salmonella typhimurium. Four weeks after...... as low as 10(4) cells from both euthymic or thymus-grafted animals were effective, and athymic and euthymic recipients survived equally well. Four weeks after the infection both athymic and euthymic animals housed very few bacteria and had high antibacterial antibody titres. The percentages of splenic...... and lymph node CD4+ cells in the athymic rats were comparable to those found in the euthymic animals. The study shows that primed CD4+ lymphocytes even in very low doses are able to induce immunity against a Salmonella typhimurium infection....

  11. Investigation and management of an outbreak of Salmonella Typhimurium DT8 associated with duck eggs, Ireland 2009 to 2011.

    LENUS (Irish Health Repository)

    Garvey, P

    2013-01-01

    Salmonella Typhimurium DT8 was a very rare cause of human illness in Ireland between 2000 and 2008, with only four human isolates from three patients being identified. Over a 19-month period between August 2009 and February 2011, 34 confirmed cases and one probable case of Salmonella Typhimurium DT8 were detected, all of which had an MLVA pattern 2-10-NA-12-212 or a closely related pattern. The epidemiological investigations strongly supported a linkbetween illness and exposure to duck eggs. Moreover, S. Typhimurium with an MLVA pattern indistinguishable (or closely related) to the isolates from human cases, was identified in 22 commercial and backyard duck flocks, twelve of which were linked with known human cases. A range of control measures were taken at farm level, and advice was provided to consumers on the hygienic handling and cooking of duck eggs. Although no definitive link was established with a concurrent duck egg-related outbreak of S. Typhimurium DT8 in the United Kingdom, it seems likely that the two events were related. It may be appropriate for other countries with a tradition of consuming duck eggs to consider the need for measures to reduce the risk of similar outbreaks.

  12. Therapeutic efficacy of tumor-targeting Salmonella typhimurium A1-R on human colorectal cancer liver metastasis in orthotopic nude-mouse models.

    Science.gov (United States)

    Murakami, Takashi; Hiroshima, Yukihiko; Zhao, Ming; Zhang, Yong; Chishima, Takashi; Tanaka, Kuniya; Bouvet, Michael; Endo, Itaru; Hoffman, Robert M

    2015-10-13

    Liver metastasis is the most frequent cause of death from colon and other cancers. Generally, liver metastasis is recalcitrant to treatment. The aim of this study is to determine the efficacy of tumor-targeting Salmonella typhimurium A1-R on liver metastasis in orthotopic mouse models. HT-29 human colon cancer cells expressing red fluorescent protein (RFP) were used in the present study. S. typhimurium A1-R infected HT-29 cells in a time-dependent manner, inhibiting cancer-cell proliferation in vitro. S. typhimurium A1-R promoted tumor necrosis and inhibited tumor growth in a subcutaneous tumor mouse model of HT-29-RFP. In orthotopic mouse models, S. typhimurium A1-R targeted liver metastases and significantly reduced their growth. The results of this study demonstrate the future clinical potential of S. typhimurium A1-R targeting of liver metastasis.

  13. Iron acquisition pathways and colonization of the inflamed intestine by Salmonella enterica serovar Typhimurium

    OpenAIRE

    Costa, Luciana F.; Mol, Juliana P. S.; Silva, Ana Patricia C.; Macêdo,Auricélio A.; Silva, Teane M. A.; Alves, Geraldo E.S.; Winter, Sebastian; Winter, Maria G.; Velazquez, Eric M; Byndloss, Mariana X.; Bäumler, Andreas J.; Tsolis, Renée M.; Paixão, Tatiane A.; Renato L Santos

    2016-01-01

    Salmonella enterica serotype Typhimurium is able to expand in the lumen of the inflamed intestine through mechanisms that have not been fully resolved. Here we utilized streptomycin-pretreated mice and dextran sodium sulfate (DSS)-treated mice to investigate how pathways for S. Typhimurium iron acquisition contribute to pathogen expansion in the inflamed intestine. Competitive infection with an iron uptake-proficient S. Typhimurium strain and mutant strains lacking tonB feoB, feoB, tonB or ir...

  14. Phytogenic feed additives in piglets challenged with Salmonella Typhimurium

    Directory of Open Access Journals (Sweden)

    Daniel Gonçalves Bruno

    2013-02-01

    Full Text Available The effects of phytogenic feed additives on piglet performance and fecal score (FDD, as well as on lipid oxidation of pork meat were evaluated. One hundred and twenty crossbred weaned piglets were randomly assigned to six treatments according to a 2 × 3 factorial design with five replicates per treatment. Factors were: challenge with Salmonella Typhimurium at 35 days of age or no challenge, and three different additives (control (CTR, basal diet; phytogenic feed additives (PHY, basal diet plus 2000 ppm of phytogenic feed additives - Rosmarinus officinalis, Mentha piperita, Lippia sidoides and Porophyllum ruderale; and antimicrobial agent (ATB, basal diet plus 100 ppm of tylosin, 2000 ppm of zinc and colistin sulfate, 30 ppm in the pre-starter basal diet, 10 ppm in the starter basal diet I and II, and 5 ppm in growth and finishing basal diet. Body weight (BW of the piglets of ATB was greater throughout the experimental period, without any differences detected between CTR and PHY. Nevertheless, from 96 to 106 days of age, the BW of the CTR group was greater than PHY. From 21 to 34 days of age, feed conversion of ATB was lower than CTR; however, PHY showed an intermediate result, which did not differ from either ATB or CTR. Challenged animals reduced feed intake from day 35 to 48 compared with unchallenged animals. Piglet performance and fecal score from 21 to 48 days of age were lower in piglets that received ATB compared with the other treatments. However, from 35 to 48 days of age, the FDD of PHY was lower than CTR. Lipid oxidation was not reduced in treated animals. Antimicrobial agent improved the growth performance of piglets until 63 days of age, and no difference was observed between the treatments from 64 to 131 days of age. Antimicrobial agent reduced FDD; the FDD of PHY was similar to that of ATB after 48 days. None of the treatments affected lipid oxidation of pork meat.

  15. Experimental infection of broiler chicks with Salmonella Typhimurium from pigeon (Columba livia

    Directory of Open Access Journals (Sweden)

    Átilla Holanda de Albuquerque

    2016-08-01

    Full Text Available Several cases of animal and human salmonellosis caused by the Salmonella serotype Typhimurium have been reported. In animals, subclinical infection favors pathogen dissemination through feces. In this context, the domestic pigeon (Columba livia with an asymptomatic condition may play an important role in the transmission of salmonellosis, through the elimination of contaminated feces in commercial aviaries or in poultry feed facilities, causing economic losses to the poultry industry and presenting a risk to public health. This study aimed to evaluate the mortality, clinical signs and the presence of Salmonella Typhimurium in the feces and organs of chicks previously inoculated with bacteria isolated from a pigeon. One-day-old chicks were distributed in two experimental groups (G1 and G2 of 32 birds each, and a control group of six birds. Two inocula of 0.4 and 0.7 mL with 105 and 106 colony forming units were used in G1 and G2 birds, respectively. At 1, 4, 7 and 14 days post-inoculation (dpi fecal samples were pooled from each cage and individual cloacal swabs were collected. At 14 dpi, all chicks were euthanized and samples were collected from the liver, spleen, lung, cecum and intestine for microbiological analysis. Mortality was only observed among G2 birds (6.25%. Most birds presented clinical signs of diarrhea at 4 dpi and no symptom as observed at 14 dpi. The results from cloacal swabs demonstrated bacterial elimination in 68.8% and 53.1% of G2 and G1 birds, respectively at 1 dpi. Additionally, fecal samples had elevated bacterial shedding in all four periods of observation , with a higher excretion at 4 dpi (62.5% for both groups. Among G2 birds, 74.2% were positive for the pathogen in the intestine; G1 birds presented the lowest rate of lung infection (29%, and both groups had more than 50% positivity for liver and caeca. The results revealed that infected chicks with a Salmonella Typhimurium strains isolated from pigeons may host the

  16. The transcriptional programme of Salmonella enterica serovar Typhimurium reveals a key role for tryptophan metabolism in biofilms.

    LENUS (Irish Health Repository)

    Hamilton, Shea

    2009-12-11

    Abstract Background Biofilm formation enhances the capacity of pathogenic Salmonella bacteria to survive stresses that are commonly encountered within food processing and during host infection. The persistence of Salmonella within the food chain has become a major health concern, as biofilms can serve as a reservoir for the contamination of food products. While the molecular mechanisms required for the survival of bacteria on surfaces are not fully understood, transcriptional studies of other bacteria have demonstrated that biofilm growth triggers the expression of specific sets of genes, compared with planktonic cells. Until now, most gene expression studies of Salmonella have focused on the effect of infection-relevant stressors on virulence or the comparison of mutant and wild-type bacteria. However little is known about the physiological responses taking place inside a Salmonella biofilm. Results We have determined the transcriptomic and proteomic profiles of biofilms of Salmonella enterica serovar Typhimurium. We discovered that 124 detectable proteins were differentially expressed in the biofilm compared with planktonic cells, and that 10% of the S. Typhimurium genome (433 genes) showed a 2-fold or more change in the biofilm compared with planktonic cells. The genes that were significantly up-regulated implicated certain cellular processes in biofilm development including amino acid metabolism, cell motility, global regulation and tolerance to stress. We found that the most highly down-regulated genes in the biofilm were located on Salmonella Pathogenicity Island 2 (SPI2), and that a functional SPI2 secretion system regulator (ssrA) was required for S. Typhimurium biofilm formation. We identified STM0341 as a gene of unknown function that was needed for biofilm growth. Genes involved in tryptophan (trp) biosynthesis and transport were up-regulated in the biofilm. Deletion of trpE led to decreased bacterial attachment and this biofilm defect was restored by

  17. Global Screening ofSalmonella entericaSerovar Typhimurium Genes for Desiccation Survival.

    Science.gov (United States)

    Mandal, Rabindra K; Kwon, Young M

    2017-01-01

    Salmonella spp., one of the most common foodborne bacterial pathogens, has the ability to survive under desiccation conditions in foods and food processing facilities for years. This raises the concerns of Salmonella infection in humans associated with low water activity foods. Salmonella responds to desiccation stress via complex pathways involving immediate physiological actions as well as coordinated genetic responses. However, the exact mechanisms of Salmonella to resist desiccation stress remain to be fully elucidated. In this study, we screened a genome-saturating transposon (Tn5) library of Salmonella Typhimurium ( S . Typhimurium) 14028s under the in vitro desiccation stress using transposon sequencing (Tn-seq). We identified 61 genes and 6 intergenic regions required to overcome desiccation stress. Salmonella desiccation resistance genes were mostly related to energy production and conversion; cell wall/membrane/envelope biogenesis; inorganic ion transport and metabolism; regulation of biological process; DNA metabolic process; ABC transporters; and two component system. More than 20% of the Salmonella desiccation resistance genes encode either putative or hypothetical proteins. Phenotypic evaluation of 12 single gene knockout mutants showed 3 mutants ( atpH, atpG , and corA ) had significantly ( p survival as compared to the wild type during desiccation survival. Thus, our study provided new insights into the molecular mechanisms utilized by Salmonella for survival against desiccation stress. The findings might be further exploited to develop effective control strategies against Salmonella contamination in low water activity foods and food processing facilities.

  18. Structure Prediction of Outer Membrane Protease Protein of Salmonella typhimurium Using Computational Techniques

    Directory of Open Access Journals (Sweden)

    Rozina Tabassum

    2016-03-01

    Full Text Available Salmonella typhimurium, a facultative gram-negative intracellular pathogen belonging to family Enterobacteriaceae, is the most frequent cause of human gastroenteritis worldwide. PgtE gene product, outer membrane protease emerges important in the intracellular phases of salmonellosis. The pgtE gene product of S. typhimurium was predicted to be capable of proteolyzing T7 RNA polymerase and localize in the outer membrane of these gram negative bacteria. PgtE product of S. enterica and OmpT of E. coli, having high sequence similarity have been revealed to degrade macrophages, causing salmonellosis and other diseases. The three-dimensional structure of the protein was not available through Protein Data Bank (PDB creating lack of structural information about E protein. In our study, by performing Comparative model building, the three dimensional structure of outer membrane protease protein was generated using the backbone of the crystal structure of Pla of Yersinia pestis, retrieved from PDB, with MODELLER (9v8. Quality of the model was assessed by validation tool PROCHECK, web servers like ERRAT and ProSA are used to certify the reliability of the predicted model. This information might offer clues for better understanding of E protein and consequently for developmet of better therapeutic treatment against pathogenic role of this protein in salmonellosis and other diseases.

  19. Coordinated regulation of virulence during systemic infection of Salmonella enterica serovar Typhimurium.

    Directory of Open Access Journals (Sweden)

    Hyunjin Yoon

    2009-02-01

    Full Text Available To cause a systemic infection, Salmonella must respond to many environmental cues during mouse infection and express specific subsets of genes in a temporal and spatial manner, but the regulatory pathways are poorly established. To unravel how micro-environmental signals are processed and integrated into coordinated action, we constructed in-frame non-polar deletions of 83 regulators inferred to play a role in Salmonella enteriditis Typhimurium (STM virulence and tested them in three virulence assays (intraperitoneal [i.p.], and intragastric [i.g.] infection in BALB/c mice, and persistence in 129X1/SvJ mice. Overall, 35 regulators were identified whose absence attenuated virulence in at least one assay, and of those, 14 regulators were required for systemic mouse infection, the most stringent virulence assay. As a first step towards understanding the interplay between a pathogen and its host from a systems biology standpoint, we focused on these 14 genes. Transcriptional profiles were obtained for deletions of each of these 14 regulators grown under four different environmental conditions. These results, as well as publicly available transcriptional profiles, were analyzed using both network inference and cluster analysis algorithms. The analysis predicts a regulatory network in which all 14 regulators control the same set of genes necessary for Salmonella to cause systemic infection. We tested the regulatory model by expressing a subset of the regulators in trans and monitoring transcription of 7 known virulence factors located within Salmonella pathogenicity island 2 (SPI-2. These experiments validated the regulatory model and showed that the response regulator SsrB and the MarR type regulator, SlyA, are the terminal regulators in a cascade that integrates multiple signals. Furthermore, experiments to demonstrate epistatic relationships showed that SsrB can replace SlyA and, in some cases, SlyA can replace SsrB for expression of SPI-2 encoded

  20. Survivability of Salmonella typhimurium L1388 and Salmonella enteritidis L1225 under stressful growth conditions

    Directory of Open Access Journals (Sweden)

    Ngwai YB

    2007-11-01

    Full Text Available In an earlier study with Salmonella typhimurium L1388 (ST and Salmonella enteritidis L1225 (SE isolated from diseased chickens, we found that SE formed more biofilm than ST on abiotic surfaces in a time-dependent manner. Since the ability of salmonellae to survive extreme environment is related to their virulence, the present study examined the survival of Salmonella typhimurium L1388 and Salmonella nteritidis L1225 under the usual stresses that salmonellae encounter during their life cycle. This is with a view to understanding the strains’ stress tolerance that could be used to explain their virulence. Incubation at 37oC for various time periods was done for: i stationary phase (SP cells at pH 2.6; ii log-phase (LP cells at pH 4.0; log-phase or stationary phase cells in broth containing iii hydrogen peroxide, iv sodium chloride and v ethanol; vi stationary phase cells in Hank’s balanced salt solution (single strength containing 10% human serum; and vii prolong stationary phase cells. Stationary phase cells were also incubated at 52oC for 15 min. Surviving cells at the various incubation times were counted on trypticase soy agar (TSA after appropriate dilution in saline and overnight incubation at 37oC. Growth iron-poor medium was determined by growing a single bacterial colony in Medium A with shaking at 37oC or 40oC for 24 h. Statistics was done by one-way analysis-of-variance (ANOVA at P = 0.05. Differences in the survival of ST and SE were insignificant (p>0.05 in acid pH at both pH 4.0 (p = 0.3783 and pH 2.6 (p = 0.4711; at high salinity for log-phase (p = 0.1416 and stationary phase (p = 0.1816 cells; in ethanol (p = 0.5984, human serum (p = 0.8139, prolonged stationary phase (p = 0.3506; and under heat (p = 0.5766. SE was significantly (p<0.05; p = 0.0031 more tolerant to oxidative-killing by hydrogen peroxide. Culturable growth of the ST and SE in an iron-poor medium A revealed insignificant differences at 37oC (p = 0.8381 but

  1. Characterisation of Salmonella enterica serotype Typhimurium isolates from wild birds in northern England from 2005 – 2006

    Directory of Open Access Journals (Sweden)

    de Pinna Elizabeth

    2008-01-01

    Full Text Available Abstract Background Several studies have shown that a number of serovars of Salmonella enterica may be isolated from wild birds, and it has been suggested that wild birds may play a role in the epidemiology of human and livestock salmonellosis. However, little is known about the relationship between wild bird S. enterica strains and human- and livestock- associated strains in the United Kingdom. Given the zoonotic potential of salmonellosis, the main aim of this study was to investigate the molecular epidemiology of S. enterica infections in wild birds in the north of England and, in particular, to determine if wild bird isolates were similar to those associated with disease in livestock or humans. Results Thirty two Salmonella enterica isolates were collected from wild birds in northern England between February 2005 and October 2006, of which 29 were S. enterica serovar Typhimurium (S. Typhimurium; one S. Newport, one S. Senftenberg, and one isolate could not be classified by serotyping. Further analysis through phage typing and macro-restriction pulsed-field gel electrophoresis indicated that wild passerine deaths associated with salmonellosis were caused by closely-related S. Typhimurium isolates, some of which were clonal. These isolates were susceptible to all antimicrobials tested, capable of invading and persisting within avian macrophage-like HD11 cells in vitro, and contained a range of virulence factors associated with both systemic and enteric infections of birds and mammals. However, all the isolates lacked the sopE gene associated with some human and livestock disease outbreaks caused by S. Typhimurium. Conclusion The wild bird isolates of S. enterica characterised in this investigation may not represent a large zoonotic risk. Molecular characterisation of isolates suggested that S. Typhimurium infection in wild passerines is maintained within wild bird populations and the causative strains may be host-adapted.

  2. Interleukin-10 Production by T and B Cells Is a Key Factor to Promote Systemic Salmonella enterica Serovar Typhimurium Infection in Mice

    Directory of Open Access Journals (Sweden)

    Geraldyne A. Salazar

    2017-08-01

    Full Text Available Salmonella enterica serovar Typhimurium (S. Typhimurium is a Gram-negative bacterium that produces disease in numerous hosts. In mice, oral inoculation is followed by intestinal colonization and subsequent systemic dissemination, which leads to severe pathogenesis without the activation of an efficient anti-Salmonella immune response. This feature suggests that the infection caused by S. Typhimurium may promote the production of anti-inflammatory molecules by the host that prevent efficient T cell activation and bacterial clearance. In this study, we describe the contribution of immune cells producing the anti-inflammatory cytokine interleukin-10 (IL-10 to the systemic infection caused by S. Typhimurium in mice. We observed that the production of IL-10 was required by S. Typhimurium to cause a systemic disease, since mice lacking IL-10 (IL-10−/− were significantly more resistant to die after an infection as compared to wild-type (WT mice. IL-10−/− mice had reduced bacterial loads in internal organs and increased levels of pro-inflammatory cytokines in serum at 5 days of infection. Importantly, WT mice showed high bacterial loads in tissues and no increase of cytokines in serum after 5 days of S. Typhimurium infection, except for IL-10. In WT mice, we observed a peak of il-10 messenger RNA production in ileum, spleen, and liver after 5 days of infection. Importantly, the adoptive transfer of T or B cells from WT mice restored the susceptibility of IL-10−/− mice to systemic S. Typhimurium infection, suggesting that the generation of regulatory cells in vivo is required to sustain a systemic infection by S. Typhimurium. These findings support the notion that IL-10 production from lymphoid cells is a key process in the infective cycle of S. Typhimurium in mice due to generation of a tolerogenic immune response that prevents bacterial clearance and supports systemic dissemination.

  3. 2D proteome analysis initiates new Insights on the Salmonella Typhimurium LuxS protein

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    Vanderleyden Jos

    2009-09-01

    Full Text Available Abstract Background Quorum sensing is a term describing a bacterial communication system mediated by the production and recognition of small signaling molecules. The LuxS enzyme, catalyzing the synthesis of AI-2, is conserved in a wide diversity of bacteria. AI-2 has therefore been suggested as an interspecies quorum sensing signal. To investigate the role of endogenous AI-2 in protein expression of the Gram-negative pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium, we performed a 2D-DIGE proteomics experiment comparing total protein extract of wildtype S. Typhimurium with that of a luxS mutant, unable to produce AI-2. Results Differential proteome analysis of wildtype S. Typhimurium versus a luxS mutant revealed relatively few changes beyond the known effect on phase 2 flagellin. However, two highly differentially expressed protein spots with similar molecular weight but differing isoelectric point, were identified as LuxS whereas the S. Typhimurium genome contains only one luxS gene. This observation was further explored and we show that the S. Typhimurium LuxS protein can undergo posttranslational modification at a catalytic cysteine residue. Additionally, by constructing LuxS-βla and LuxS-PhoA fusion proteins, we demonstrate that S. Typhimurium LuxS can substitute the cognate signal peptide sequences of β-lactamase and alkaline phosphatase for translocation across the cytoplasmic membrane in S. Typhimurium. This was further confirmed by fractionation of S. Typhimurium protein extracts, followed by Western blot analysis. Conclusion 2D-DIGE analysis of a luxS mutant vs. wildtype Salmonella Typhimurium did not reveal new insights into the role of AI-2/LuxS in Salmonella as only a small amount of proteins were differentially expressed. However, subsequent in depth analysis of the LuxS protein itself revealed two interesting features: posttranslational modification and potential translocation across the cytoplasmic membrane. As

  4. Modification of Salmonella Typhimurium motility by the probiotic yeast strain Saccharomyces boulardii.

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    Rodolphe Pontier-Bres

    Full Text Available BACKGROUND: Motility is an important component of Salmonella enterica serovar Typhimurium (ST pathogenesis allowing the bacteria to move into appropriate niches, across the mucus layer and invade the intestinal epithelium. In vitro, flagellum-associated motility is closely related to the invasive properties of ST. The probiotic yeast Saccharomyces boulardii BIOCODEX (S.b-B is widely prescribed for the prophylaxis and treatment of diarrheal diseases caused by bacteria or antibiotics. In case of Salmonella infection, S.b-B has been shown to decrease ST invasion of T84 colon cell line. The present study was designed to investigate the impact of S.b-B on ST motility. METHODOLOGY/PRINCIPAL FINDINGS: Experiments were performed on human colonic T84 cells infected by the Salmonella strain 1344 alone or in the presence of S.b-B. The motility of Salmonella was recorded by time-lapse video microscopy. Next, a manual tracking was performed to analyze bacteria dynamics (MTrackJ plugin, NIH image J software. This revealed that the speed of bacterial movement was modified in the presence of S.b-B. The median curvilinear velocity (CLV of Salmonella incubated alone with T84 decreased from 43.3 µm/sec to 31.2 µm/sec in the presence of S.b-B. Measurement of track linearity (TL showed similar trends: S.b-B decreased by 15% the number of bacteria with linear tract (LT and increased by 22% the number of bacteria with rotator tract (RT. Correlation between ST motility and invasion was further established by studying a non-motile flagella-deficient ST strain. Indeed this strain that moved with a CLV of 0.5 µm/sec, presented a majority of RT and a significant decrease in invasion properties. Importantly, we show that S.b-B modified the motility of the pathogenic strain SL1344 and significantly decreased invasion of T84 cells by this strain. CONCLUSIONS: This study reveals that S.b-B modifies Salmonella's motility and trajectory which may account for the modification

  5. Coordinated Regulation of Virulence during Systemic Infection of Salmonella enterica serovar Typhimurium

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    Yoon, Hyunjin; McDermott, Jason E.; Porwollik, Steffen; Mcclelland, Michael; Heffron, Fred

    2009-02-20

    Salmonella must respond to a myriad of environmental cues during infection of a mouse and express specific subsets of genes in a temporal and spatial manner to subvert the host defense mechanisms but these regulatory pathways are poorly established. To unravel how micro-environmental signals are processed and integrated into coordinated action, we constructed in-frame non-polar deletions of 84 regulators inferred to play a role in Salmonella typhimurium virulence and tested them in three virulence assays (intraperitoneal (i.p.), and intragastric (i.g.) infection in BALB/c mice, and persistence in SvJ129 mice). Overall 36 regulators were identified that were less virulent in at least one assay, and of those, 15 regulators were required for systemic mouse infection in an acute infection model. As a first step towards understanding the interplay between a pathogen and its host from a systems biology standpoint we focused on these 15 genes. Transcriptional profiles were obtained for each of these 15 regulators from strains grown under four different environmental conditions. These results as well as publicly available transcriptional profiles were analyzed using both network inference and cluster analysis algorithms. The analysis predicts a regulatory network in which all 15 regulators control a specific set of genes necessary for Salmonella to cause systemic infection. We tested the regulatory model by expressing a subset of the regulators in trans and monitoring transcription of 7 known virulence factors located within Salmonella pathogenicity island 2 (SPI-2). These experiments validated the regulatory model and showed that, for these 7 genes, the response regulator SsrB and the marR type regulator SlyA co-regulate in a regulatory cascade by integrating multiple signals.

  6. Subversion of innate and adaptive immune activation induced by structurally modified lipopolysaccharide from Salmonella typhimurium

    Science.gov (United States)

    Pastelin-Palacios, Rodolfo; Gil-Cruz, Cristina; Pérez-Shibayama, Christian I; Moreno-Eutimio, Mario A; Cervantes-Barragán, Luisa; Arriaga-Pizano, Lourdes; Ludewig, Burkhard; Cunningham, Adam F; García-Zepeda, Eduardo A; Becker, Ingeborg; Alpuche-Aranda, Celia; Bonifaz, Laura; Gunn, John S; Isibasi, Armando; López-Macías, Constantino

    2011-01-01

    Salmonella are successful pathogens that infect millions of people every year. During infection, Salmonella typhimurium changes the structure of its lipopolysaccharide (LPS) in response to the host environment, rendering bacteria resistant to cationic peptide lysis in vitro. However, the role of these structural changes in LPS as in vivo virulence factors and their effects on immune responses and the generation of immunity are largely unknown. We report that modified LPS are less efficient than wild-type LPS at inducing pro-inflammatory responses. The impact of this LPS-mediated subversion of innate immune responses was demonstrated by increased mortality in mice infected with a non-lethal dose of an attenuated S. typhimurium strain mixed with the modified LPS moieties. Up-regulation of co-stimulatory molecules on antigen-presenting cells and CD4+ T-cell activation were affected by these modified LPS. Strains of S. typhimurium carrying structurally modified LPS are markedly less efficient at inducing specific antibody responses. Immunization with modified LPS moiety preparations combined with experimental antigens, induced an impaired Toll-like receptor 4-mediated adjuvant effect. Strains of S. typhimurium carrying structurally modified LPS are markedly less efficient at inducing immunity against challenge with virulent S. typhimurium. Hence, changes in S. typhimurium LPS structure impact not only on innate immune responses but also on both humoral and cellular adaptive immune responses. PMID:21631497

  7. Acid resistance variability among isolates of Salmonella enterica serovar Typhimurium DT104

    NARCIS (Netherlands)

    Berk, P.A.; Jonge, de R.; Zwietering, M.H.; Abee, T.; Kieboom, J.

    2005-01-01

    Aims: Acid resistance could be an indicator of virulence since acid resistant strains are able to better survive the human stomach passage and in macrophages. We studied the acid resistance of several Salmonella Typhimurium DT104 strains isolated from food and humans and identified cellular

  8. Comparison between digital PCR and real-time PCR in detection of Salmonella typhimurium in milk.

    Science.gov (United States)

    Wang, Meng; Yang, Junjie; Gai, Zhongtao; Huo, Shengnan; Zhu, Jianhua; Li, Jun; Wang, Ranran; Xing, Sheng; Shi, Guosheng; Shi, Feng; Zhang, Lei

    2018-02-02

    As a kind of zero-tolerance foodborne pathogens, Salmonella typhimurium poses a great threat to quality of food products and public health. Hence, rapid and efficient approaches to identify Salmonella typhimurium are urgently needed. Combined with PCR and fluorescence technique, real-time PCR (qPCR) and digital PCR (ddPCR) are regarded as suitable tools for detecting foodborne pathogens. To compare the effect between qPCR and ddPCR in detecting Salmonella typhimurium, a series of nucleic acid, pure strain culture and spiking milk samples were applied and the resistance to inhibitors referred in this article as well. Compared with qPCR, ddPCR exhibited more sensitive (10 -4 ng/μl or 10 2 cfu/ml) and less pre-culturing time (saving 2h). Moreover, ddPCR had stronger resistance to inhibitors than qPCR, yet absolute quantification hardly performed when target's concentration over 1ng/μl or 10 6 cfu/ml. This study provides an alternative strategy in detecting foodborne Salmonella typhimurium. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. LeuO is a global regulator of gene expression in Salmonella enterica serovar Typhimurium

    DEFF Research Database (Denmark)

    Dillon, Shane C.; Espinosa, Elena; Hokamp, Karsten

    2012-01-01

    We report the first investigation of the binding of the Salmonella enterica LeuO LysR‐type transcription regulator to its genomic targets in vivo. Chromatin‐immunoprecipitation‐on‐chip identified 178 LeuO binding sites on the chromosome of S. enterica serovar Typhimurium strain SL1344. These site...

  10. Polisakarida Mengandung Mannan dari Bungkil Inti Sawit Sebagai Antimikroba Salmonella typhimurium pada Ayam

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    M. Tafsin

    2007-08-01

    Full Text Available Mannan containing polysaccharides could be used as an alternative to replace antibiotics due to their capacity to block the colonization of pathogenic bacteria in the intestine of poultry. The aim of this study was to investigate mannan containing polysaccharides from palm kernel meal (PKM and its inhibitory effect against Salmonella typhimurium. Hot water extractions were used to isolate mannan containing polysaccharides from cell wall of PKM. In vivo studies were conducted using broiler and layer chicks that were challenged orally with 104 cfu Salmonella typhimurium on third day. Split plot design was used as experimental design with strain as main plot and level of mannan polysaccharides as sub plot. The levels of mannan containing polysaccharides that were used consisted of 0 (R0; 1000 (R1; 2000 (R2; 3000 (R3; 4000 (R4 ppm, in term of total sugar. The results indicated that compared to the control group, feeding PKM containing mannan 4000 ppm decreased (P<0.01 Salmonella typhimurium incidence. The addition of mannan did not affect feed consumption. On the contrary, the addition of 4000 ppm mannan gave significantly higher feed/weight gain ratio of the chicks (P<0.05. The administration of feed supplemented with mannan from PKM did not influence weight gain of poultry. It is concluded that mannan from PKM can prevent the colonization of Salmonella typhimurium in poultry.

  11. Structure of Salmonella typhimurium OMP Synthase in a Complete Substrate Complex

    DEFF Research Database (Denmark)

    Grubmeyer, Charles; Hansen, Michael Riis; Fedorov, Alexander A.

    2012-01-01

    Dimeric Salmonella typhimurium orotate phosphoribosyltransferase (OMP synthase, EC 2.4.2.10), a key enzyme in de novo pyrimidine nucleotide synthesis, has been cocrystallized in a complete substrate E·MgPRPP·orotate complex and the structure determined to 2.2 Å resolution. This structure resem...

  12. Risk factors for clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on Dutch dairy farms

    NARCIS (Netherlands)

    Veling, J.; Wilpshaar, H.; Frankena, K.; Bartels, C.; Barkema, H.W.

    2002-01-01

    Risk factors for outbreaks in 1999 of clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on dairy farms were studied in a matched case–control study with 47 case farms and 47 control farms. All 47 case farms experienced a clinical outbreak of salmonellosis which was confirmed

  13. Rice hull smoke extract inactivates Salmonella Typhimurium in laboratory media and protects infected mice against mortality

    Science.gov (United States)

    A recently discovered and characterized rice hull liquid smoke extract was tested for bactericidal activity against Salmonella Typhimurium using the disc-agar method. The Minimum Inhibitory Concentration (MIC) value of rice hull smoke extract was found to be 0.822% (v/v). The in vivo antibacterial a...

  14. Regulation of Salmonella typhimurium pyr Gene Expression: Effect of Changing Both Purine and Pyrimidine Nucleotide Pools

    DEFF Research Database (Denmark)

    Jensen, Kaj Frank

    1989-01-01

    The synthesis of the pyrimidine biosynthetic enzymes is repressed by the pyrimidine nucleotide end-products of the pathway. However, purine nucleotides also play a role. In this study, I have measured expression of the pyr genes (pyrA-E) in Salmonella typhimurium strains harbouring mutations...... of each pyr gene is discussed in relation to present knowledge on gene structure and regulatory mechanism....

  15. Molecular characterization of antibiotic resistant Salmonella Typhimurium and Salmonella Kentucky isolated from pre- and post-chill whole broilers carcasses.

    Science.gov (United States)

    Mohamed, Tagelsir; Zhao, Shaohua; White, David G; Parveen, Salina

    2014-04-01

    There is conflicting data regarding whether commercial chilling has any effect on persistence of Salmonella serovars, including antibiotic resistant variants, on chicken carcasses. A total of 309 Salmonella Typhimurium and Salmonella Kentucky isolates recovered from pre- and post-chill whole broiler carcasses were characterized for genetic relatedness using Pulsed Field Gel Electrophoresis (PFGE) and for the presence of virulence factors (invA, pagC, spvC) by PCR and for aerobactin and colicin production by bioassays. A subset of these isolates (n = 218) displaying resistance to either sulfisoxazole and/or ceftiofur [S. Typhimurium (n = 66) and S. Kentucky (n = 152)] were further tested for the presence of associated antibiotic resistance elements (class-I integrons and blaCMY genes) by PCR. All 145 ceftiofur resistant S. Kentucky and S. Typhimurium isolates possessed blaCMY genes. Class-I integrons were only detected in 6.1% (n = 4/66) of sulfisoxazole resistant S. Typhimurium isolates. The PFGE analysis revealed the presence of genetically diverse populations within the recovered isolates but clusters were generally concordant with serotypes and antimicrobial resistance profiles. At a 100% pattern similarity index, thirty-six percent of the undistinguishable S. Typhimurium and 22% of the undistinguishable S. Kentucky isolates were recovered from the same chilling step. All isolates possessed the invA and pagC genes, but only 1.4%possessed spvC. Irrespective of the chilling step, there was a significant difference (P Salmonella clonal groups but had no effect on the presence of class-I integrons, blaCMY genes, and tested virulence factors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Detection of Salmonella typhimurium in retail chicken meat and chicken giblets.

    Science.gov (United States)

    El-Aziz, Doaa M Abd

    2013-09-01

    To detect Salmonella typhimurium (S. typhimurium), one of the most frequently isolated serovars from food borne outbreaks throughout the world, in retail raw chicken meat and giblets. One hundred samples of retail raw chicken meat and giblets (Liver, heart and gizzard) which were collected from Assiut city markets for detection of the organism and by using Duplex PCR amplification of DNA using rfbJ and fliC genes. S. typhimurium was detected at rate of 44%, 40% and 48% in chicken meat, liver and heart, respectively, but not detected in gizzard. The results showed high incidence of S. typhimurium in the examined samples and greater emphasis should be applied on prevention and control of contamination during processing for reducing food-borne risks to consumers.

  17. Inactivation of Salmonella enterica serovar Typhimurium on fresh produce by cold atmospheric gas plasma technology.

    Science.gov (United States)

    Fernández, A; Noriega, E; Thompson, A

    2013-02-01

    Cold atmospheric gas plasma treatment (CAP) is an alternative approach for the decontamination of fresh and minimally processed food. In this study, the effects of growth phase, growth temperature and chemical treatment regime on the inactivation of Salmonella enterica serovar Typhimurium (S. Typhimurium) by Nitrogen CAP were examined. Furthermore, the efficacy of CAP treatment for decontaminating lettuce and strawberry surfaces and potato tissue inoculated with S. Typhimurium was evaluated. It was found that the rate of inactivation of S. Typhimurium was independent of the growth phase, growth temperature and chemical treatment regime. Under optimal conditions, a 2 min treatment resulted in a 2.71 log-reduction of S. Typhimurium viability on membrane filters whereas a 15 min treatment was necessary to achieve 2.72, 1.76 and 0.94 log-reductions of viability on lettuce, strawberry and potato, respectively. We suggest that the differing efficiency of CAP treatment on the inactivation of S. Typhimurium on these different types of fresh foods is a consequence of their surface features. Scanning electron microscopy of the surface structures of contaminated samples of lettuce, strawberry and potato revealed topographical features whereby S. Typhimurium cells could be protected from the active species generated by plasma. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Isolation and Characterization of Salmonella Enterica Serovar Typhimurium Circulating Among Healthy Chickens of Bangladesh

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    Md. Shafiullah Parvej

    2016-07-01

    Full Text Available Salmonella is considered as a global problem ranking first among food borne diseases. All motile Salmonella of poultry origin are zoonotic and readily transmit to human via meat and eggs but reports on non - typhoidal Salmonella serovars circulating in layer chickens is very limited in South-East Asian countries including Bangladesh. Salmonella serovars isolated from apparently healthy chickens were characterized in the present study. Of 170 samples (cloacal swab 150 and feed 20 collected from commercial layer farms, motile Salmonella was isolated 4% (6/150 and 50% (10/20 respectively by cultural, biochemical, motility test and by detection of hisJ gene. About 5% (8/170 samples possessed serovar-specific gene fimA, suggesting that isolates were Salmonella enterica serovar Typhimurium. Antimicrobial susceptibility testing demonstrated that the isolated serovars were multidrug resistant. Therefore apparently healthy layer chickens harbour and transmit S. Typhimurium to the environment, although little is alarming since it has zoonotic significance and the isolates were resistant to commonly used first line of antibiotic in Salmonella infection.

  19. Killed but metabolically active Salmonella typhimurium: application of a new technology to an old vector.

    Science.gov (United States)

    Lankowski, Alexander J; Hohmann, Elizabeth L

    2007-04-15

    Previous studies have shown that attenuated salmonellae utilized as vaccine vectors engender strong immune responses; however, balancing immunogenicity with reactogenicity remains problematic. Recent work in other bacteria has shown that photochemical treatment of DNA excision repair mutants ( Delta uvrAB) renders organisms "killed but metabolically active" (KBMA). Here, we extend this concept to Salmonella typhimurium. A strain of attenuated S. typhimurium previously evaluated in human volunteers was further deleted for uvrAB genes and designated CKS362. Photochemical treatment of CKS362 resulted in significant inactivation. These KBMA organisms were metabolically active as shown by radioactive methionine incorporation and lactate dehydrogenase activity. In mice inoculated intraperitoneally, KBMA CKS362 was markedly less reactogenic and stimulated a humoral immune equivalent to its live counterpart. Because the parental strain has previously been found to elicit strong immune responses to Salmonella antigens, we propose CKS362 as a prototype strain to test the immunogenicity of KBMA organisms in humans.

  20. Inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in black pepper and red pepper by gamma irradiation.

    Science.gov (United States)

    Song, Won-Jae; Sung, Hye-Jung; Kim, Sung-Youn; Kim, Kwang-Pyo; Ryu, Sangryeol; Kang, Dong-Hyun

    2014-02-17

    This study evaluated the efficacy of gamma irradiation to inactivate foodborne pathogens in black pepper (Piper nigrum) and red pepper (dried Capsicum annuum). Black pepper and red pepper inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium were subjected to gamma irradiation in the range of 0, 1, 2, 3 and 5 kGy, and color change was evaluated after treatment. Pathogen populations decreased with increasing treatment doses. A gamma irradiation dose of 5 kGy decreased E. coli O157:H7 and S. Typhimurium populations >4.4 to >5.2 log CFU/g in black pepper without causing color change. Similarly, 5 kGy of gamma irradiation yielded reduction of 3.8 to >5.2 log CFU/g for E. coli O157:H7 and S. Typhimurium in red pepper. During gamma irradiation treatment, L*, a* and b* values of red pepper were not significantly changed except for 297 μm to 420 μm size red pepper treated with 5 kGy of gamma irradiation. Based on the D-value of pathogens in black pepper and red pepper, S. Typhimurium showed more resistant to gamma irradiation than did E. coli O157:H7. These results show that gamma irradiation has potential as a non-thermal process for inactivating foodborne pathogens in spices with minimal color changes. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. A community effort towards a knowledge-base and mathematical model of the human pathogen Salmonella Typhimurium LT2

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    Shin Sook-Il

    2011-01-01

    Full Text Available Abstract Background Metabolic reconstructions (MRs are common denominators in systems biology and represent biochemical, genetic, and genomic (BiGG knowledge-bases for target organisms by capturing currently available information in a consistent, structured manner. Salmonella enterica subspecies I serovar Typhimurium is a human pathogen, causes various diseases and its increasing antibiotic resistance poses a public health problem. Results Here, we describe a community-driven effort, in which more than 20 experts in S. Typhimurium biology and systems biology collaborated to reconcile and expand the S. Typhimurium BiGG knowledge-base. The consensus MR was obtained starting from two independently developed MRs for S. Typhimurium. Key results of this reconstruction jamboree include i development and implementation of a community-based workflow for MR annotation and reconciliation; ii incorporation of thermodynamic information; and iii use of the consensus MR to identify potential multi-target drug therapy approaches. Conclusion Taken together, with the growing number of parallel MRs a structured, community-driven approach will be necessary to maximize quality while increasing adoption of MRs in experimental design and interpretation.

  2. Isolation and identification of Salmonella typhimurium from raw cow, sheep and goat milk in Chahamaha Va Bakhteyari Province

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    F Tajbakhsh

    2014-05-01

    Full Text Available Salmonella typhimurium and S. enteritidisare known as the major causes of food-borne infection throughout the world. The present study was carried out to investigate the prevalence of S. typhimurium in raw milks of Chahamaha Va Bakhteyari province. For this reason, a total of 550 raw milks (consisting of 200 cow, 175 sheep and 175 goat milk samples were collected through October 2011 to March 2012 from dairy herds around Shahrekord. The samples were cultured and the isolated colonies were confirmed by PCR using species-specific ST11 and ST15 primers. According to the results, a total of 20 samples (3.63% were found positive for Salmonellaspp.Amongst, 14 (2.54% of cow milk, 2 (0.36% of sheep milk and 4 (0.72% of goat milk samples were contaminated. Using PCR, 9 (1.63% samples were contaminated with S. typhimurium. The results indicated a relatively high occurrence of S. typhimurium in raw milks. Therefore, it is essential to maintain hygienic measures during milking and handling. Besides, it is recommended not to use raw milk for the manufacturing of dairy products such as cheese and ice-cream.

  3. Salmonella enterica serovar Typhimurium exploits inflammation to modify swine intestinal microbiota.

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    Rosanna eDrumo

    2016-01-01

    Full Text Available Salmonella enterica serovar Typhimurium is an important zoonotic gastrointestinal pathogen responsible for foodborne disease worldwide. It is a successful enteric pathogen because it has developed virulence strategies allowing it to survive in a highly inflamed intestinal environment exploiting inflammation to overcome colonization resistance provided by intestinal microbiota. In this study, we used piglets featuring an intact microbiota, which naturally develop gastroenteritis, as model for salmonellosis. We compared the effects on the intestinal microbiota induced by a wild type and an attenuated S. Typhimurium in order to evaluate whether the modifications are correlated with the virulence of the strain. This study showed that Salmonella alters microbiota in a virulence-dependent manner. We found that the wild type S. Typhimurium induced inflammation and a reduction of specific protecting microbiota species (SCFA-producing bacteria normally involved in providing a barrier against pathogens. Both these effects could contribute to impair colonization resistance, increasing the host susceptibility to wild type S. Typhimurium colonization. In contrast, the attenuated S. Typhimurium, which is characterized by a reduced ability to colonize the intestine, and by a very mild inflammatory response, was unable to successfully sustain competition with the microbiota.

  4. Involvement of MicroRNAs in Probiotics-Induced Reduction of the Cecal Inflammation by Salmonella Typhimurium

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    Qiaoling Chen

    2017-06-01

    Full Text Available The microRNAs (miRNAs have been shown to play important roles in the development of the immune system and in regulation of host inflammation responses. Probiotics can effectively alleviate the inflammation caused by Salmonella in chickens. However, whether and how miRNAs are involved in modulation of the inflammation response in the gut of chickens have not been reported. In this study, the impact of a probiotics, Lactobacillus plantarum Z01 (LPZ01, was investigated on the cecal miRNAs and cytokine secretions in Salmonella Typhimurium (S. Typhimurium-infected chickens at the age of 3 days. Newly hatched chicks were assigned to four groups (1: NC (basal diet (2: S (basal diet + S. Typhimurium challenged (3: SP (basal diet + S. Typhimurium challenged + LPZ01 (4: P (basal diet + LPZ01. In comparison with the S group, chicks in the SP group reduced the number of S. Typhimurium and had lower levels of interferon-γ and lipopolysaccharide-induced tumor necrosis factor alpha factor (LITAF in ceca post challenge. Expression of 14 miRNAs was significantly affected by the presence of S. Typhimurium and/or lactobacillus. Five differential expression miRNAs (gga-miR-215-5p, gga-miR-3525, gga-miR-193a-5p, gga-miR-122-5p, and gga-miR-375 were randomly selected for confirmation by the RT-PCR. Predicted target genes of differentially expressed miRNAs were enriched in regulation of cAMP-dependent protein kinase activity, stress-activated MAPK cascade, immune system development and regulation of immune system process as well as in immune related pathways such as MAPK and Wnt signaling pathways. The relationship between changes of miRNAs and changes of cytokines was explored. Finally, 119 novel miRNAs were identified in 36 libraries totally. Identification of novel miRNAs significantly expanded the repertoire of chicken miRNAs and provided the basis for understanding the function of miRNAs in the host. Our results suggest that the probiotics

  5. A questionnaire-based, retrospective field study of persistence of Salmonella Enteritidis and Salmonella Typhimurium in Danish broiler houses

    DEFF Research Database (Denmark)

    Gradel, K.O.; Rattenborg, Erik

    2003-01-01

    A questionnaire-based, retrospective field study was conducted in 78 Danish broiler houses (analytical units) on 42 farms. In spring 1997, all these broiler houses had been infected with Salmonella Enteritidis, phage type 8, and/or Salmonella Typhimurium, definitive-type 66, by day-old chicks del...... soap and water for washing hands in the anteroom, hygiene barriers when removing dead broilers, gravel alongside the broiler house, systematic checks of indoor rodent-bait depots, and combined surface and pulse-fogging disinfection....

  6. Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium.

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    Rui Figueiredo

    Full Text Available Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. Typhimurium in two clusters. Atypical microarray results lead to whole genome sequencing (WGS of S. Infantis Sal147, which identified deletion of thirty-eight SPI-1 genes. Sal147 was unable to invade HeLa cells and showed reduced mortality in Galleria mellonella infection model, in comparison to a SPI-1 harbouring S. Infantis. Microarray and WGS of S. Typhimurium Sal199, established for the first time in S. Typhimurium presence of cdtB and other Typhi-related genes. Characterization of Sal199 showed cdtB genes were upstream of transposase IS911, and co-expressed with other Typhi-related genes. Cell cycle arrest, cytoplasmic distension, and nuclear enlargement were detected in HeLa cells infected by Sal199, but not with S. Typhimurium LT2. Increased mortality of Galleria was detected on infection with Sal199 compared to LT2. Thus, Salmonella isolates were rapidly characterized using a high through-put microarray; helping to identify unusual virulence features which were corroborated by further characterisation. This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans. Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

  7. Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium.

    Science.gov (United States)

    Figueiredo, Rui; Card, Roderick; Nunes, Carla; AbuOun, Manal; Bagnall, Mary C; Nunez, Javier; Mendonça, Nuno; Anjum, Muna F; da Silva, Gabriela Jorge

    2015-01-01

    Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI) and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. Typhimurium in two clusters. Atypical microarray results lead to whole genome sequencing (WGS) of S. Infantis Sal147, which identified deletion of thirty-eight SPI-1 genes. Sal147 was unable to invade HeLa cells and showed reduced mortality in Galleria mellonella infection model, in comparison to a SPI-1 harbouring S. Infantis. Microarray and WGS of S. Typhimurium Sal199, established for the first time in S. Typhimurium presence of cdtB and other Typhi-related genes. Characterization of Sal199 showed cdtB genes were upstream of transposase IS911, and co-expressed with other Typhi-related genes. Cell cycle arrest, cytoplasmic distension, and nuclear enlargement were detected in HeLa cells infected by Sal199, but not with S. Typhimurium LT2. Increased mortality of Galleria was detected on infection with Sal199 compared to LT2. Thus, Salmonella isolates were rapidly characterized using a high through-put microarray; helping to identify unusual virulence features which were corroborated by further characterisation. This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans. Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

  8. Evaluation of the respiratory route as a viable portal of entry for Salmonella in poultry via intratracheal challenge of Salmonella Enteritidis and Salmonella Typhimurium.

    Science.gov (United States)

    Kallapura, G; Morgan, M J; Pumford, N R; Bielke, L R; Wolfenden, A D; Faulkner, O B; Latorre, J D; Menconi, A; Hernandez-Velasco, X; Kuttappan, V A; Hargis, B M; Tellez, G

    2014-02-01

    Experimental and epidemiological evidence suggests that primary infection of Salmonella is by the oral-fecal route for poultry. However, the airborne transmission of Salmonella and similar enteric zoonotic pathogens has been historically neglected. Increasing evidence of Salmonella bioaerosol generation in production facilities and studies suggesting the vulnerabilities of the avian respiratory architecture together have indicated the possibility of the respiratory system being a potential portal of entry for Salmonella in poultry. Presently, we evaluated this hypothesis through intratracheal (IT) administration of Salmonella Enteritidis and Salmonella Typhimurium, as separate challenges, in a total of 4 independent trials, followed by enumeration of cfu recovery in ceca-cecal tonsils and recovery incidence in liver and spleen. In all trials, both Salmonella Enteritidis and Salmonella Typhimurium, challenged IT colonized cecae to a similar or greater extent than oral administration at identical challenge levels. In most trials, chickens cultured for cfu enumeration from IT-challenged chicks at same dose as orally challenged, resulted in an increase of 1.5 log higher Salmonella Enteritidis from ceca-cecal tonsils and a much lower dose IT of Salmonella Enteritidis could colonize ceca to the same extent than a higher oral challenge. This trend of increased cecal colonization due to IT challenge was observed with all trails involving week-old birds (experiment 2 and 3), which are widely considered to be more difficult to infect via the oral route. Liver-spleen incidence data showed 33% of liver and spleen samples to be positive for Salmonella Enteritidis administered IT (10(6) cfu/chick), compared with 0% when administered orally (experiment 2, trial 1). Collectively, these data suggest that the respiratory tract may be a largely overlooked portal of entry for Salmonella infections in chickens.

  9. Saccharomyces boulardii modifies Salmonella typhimurium traffic and host immune responses along the intestinal tract.

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    Rodolphe Pontier-Bres

    Full Text Available Salmonella enterica serovar Typhimurium (ST is an enteropathogenic Gram-negative bacterium that causes infection following oral ingestion. ST spreads rapidly along the gastrointestinal tract (GIT and invades the intestinal epithelium to ultimately reach internal body organs. The probiotic yeast Saccharomyces boulardii BIOCODEX (S.b-B is prescribed for prophylaxis of diarrheal infectious diseases. We previously showed that S.b-B prevents weight loss in ST-infected mice and significantly decreases bacterial translocation to the spleen and liver. This study was designed to investigate the effect of S.b-B on ST migration along the GIT and the impact of the yeast on the host's early innate immune responses. Bioluminescent imaging (BLI was used to evaluate the effect of S.b-B on the progression of luminescent Salmonella Typhimurium (ST-lux in the GIT of mice pretreated with streptomycin. Photonic emission (PE was measured in GIT extracts (stomach, small intestine, cecum and colon at various time periods post-infection (PI. PE analysis revealed that, 45 min PI, ST-lux had migrated slightly faster in the mice treated with S.b-B than in the untreated infected animals. At 90 min PI, ST-lux had reached the cecum in both groups of mice. Adhesion of ST to S.b-B was visualized in the intestines of the mice and probably accounts for (1 the faster elimination of ST-lux in the feces, and (2 reduced translocation of ST to the spleen and liver. In the early phase of infection, S.b-B also modifies the host's immune responses by (1 increasing IFN-γ gene expression and decreasing IL-10 gene expression in the small intestine, and (2 elevating both IFN-γ, and IL-10 mRNA levels in the cecum. BLI revealed that S.b-B modifies ST migration and the host immune response along the GIT. Study findings shed new light on the protective mechanisms of S.b-B during the early phase of Salmonella pathogenesis.

  10. Salmonella identification from foods in eight hours: A prototype study with Salmonella Typhimurium

    OpenAIRE

    A Koluman; Celik, G.; Unlu, T

    2012-01-01

    Background and Objectives: The significant rise in food borne infections is mainly caused by Campylobacter spp., Salmonella serovars and Verotoxigenic Escherichia coli. As the emerging food borne pathogens cause disease, more studies have been conducted for rapid detection of these pathogens. The combination of immunomagnetic separation and polymerase chain reaction (IMS-PCR) is the most accurate and rapid test preferred by almost every researcher. Fourier Transform Infrared Spectroscopy (FTI...

  11. Acetylation regulates protein stability and DNA-binding ability of HilD to modulate Salmonella Typhimurium virulence.

    Science.gov (United States)

    Sang, Yu; Ren, Jie; Qin, Ran; Liu, Shuting; Cui, Zhongli; Cheng, Sen; Liu, Xiaoyun; Lu, Jie; Tao, Jing; Yao, Yu-Feng

    2017-02-24

    HilD, a dominant regulator of Salmonella pathogenicity island 1 (SPI-1), can be acetylated by acetyltransferase Pat in Salmonella Typhimurium, and the acetylation is beneficial to its stability. However, the underlying mechanism of HilD stability regulated by acetylation is not clear. We show here that lysine 297 (K297) located in the helix-turn-helix motif, can be acetylated by Pat. Acetylation of K297 increases HilD stability, but reduces its DNA-binding affinity. In turn, the deacetylated K297 enhances the DNA-binding ability, but decreases HilD stability. Under SPI-1 inducing condition, the acetylation level of K297 is down-regulated. The acetylated K297 (mimicked by glutamine substitution) causes attenuated invasion in HeLa cells as well as impaired virulence in mouse model compared with the deacetylated K297 (mimicked by arginine substitution), suggesting that deacetylation of K297 is essential for Salmonella virulence. These findings demonstrate that the acetylation of K297 can regulate both protein stability and DNA-binding ability. This regulation mediated by acetylation not only degrades redundant HilD to keep a moderate protein level to facilitate S. Typhimurium growth but also maintains an appropriate DNA-binding activity of HilD to ensure bacterial pathogenicity. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  12. Genotoxicity of 2-nitropropane and 1-nitropropane in Salmonella typhimurium and human lymphocytes.

    Science.gov (United States)

    Göggelmann, W; Bauchinger, M; Kulka, U; Schmid, E

    1988-03-01

    A 10- and 12-fold increase of revertant numbers could be demonstrated for 2-nitropropane (2-NP of greater than 99% purity) tested in the preincubation assay with Salmonella typhimurium strains TA 100 and TA 98 in the presence and absence of S9 mix. In the nitroreductase-deficient strains TA 100NR and TA 98NR, 2-NP was less mutagenic than in the parent strains. In human lymphocytes the induction of a weak clastogenic effect and of sister chromatid exchanges required exogenous metabolic activation. No significant mutagenic or cytogenetic response was found with 1-nitropropane of 97% purity in S. typhimurium or human lymphocytes.

  13. Persistence of Salmonella Typhimurium LT2 in Soil Enhanced after Growth in Lettuce Medium

    Directory of Open Access Journals (Sweden)

    Kornelia Smalla

    2017-04-01

    Full Text Available The persistence of Salmonella in the environment is influenced by a multitude of biotic and abiotic factors. In addition, its persistence can be influenced by preadaptation before the introduction into the environment. In order to study how preadaptation changes the survival of Salmonella in soil and therefore its potential to colonize the phytosphere, we developed a new medium based on lettuce material [lettuce medium (LM]. Salmonella enterica serovar Typhimurium strain LT2 was used as a model for Salmonella in this study. LT2 was inoculated into soil microcosms after pregrowth in Luria Bertani (LB broth or in LM. Survival of LT2 in soil was monitored over 56 days by plate counts and quantification of the Typhimurium-specific gene STM4497 using qPCR in total community DNA for which primers and TaqMan probe were designed in this study. Significantly enhanced persistence was observed for LT2 pregrown in LM compared to LT2 pregrown in LB, indicating a preadaptation effect. Surprisingly, no improved survival could be observed for S. Typhimurium strain 14028s and S. enterica serovar Senftenberg after pregrowth on LM. This indicates a high strain specificity of preadaptation. Results from previous studies suggested that biofilm formation could enhance the survival of human pathogens in various environments and might contribute to enhanced survival on plants. In vitro biofilm assays with several Salmonella strains revealed a strain-specific effect of LM on the biofilm formation. While LM significantly improved the biofilm formation of S. Senftenberg, the biofilm formation of LT2 was better in LB. This indicates that the better survival of LM-pregrown LT2 in soil was not linked to an improved ability to form biofilms but was likely due to other factors. Most importantly, this study showed that the medium used to pregrow Salmonella can influence its survival in soil and its biofilm formation which might influence the fate of Salmonella in soil.

  14. Persistence of Salmonella Typhimurium LT2 in Soil Enhanced after Growth in Lettuce Medium.

    Science.gov (United States)

    Fornefeld, Eva; Schierstaedt, Jasper; Jechalke, Sven; Grosch, Rita; Schikora, Adam; Smalla, Kornelia

    2017-01-01

    The persistence of Salmonella in the environment is influenced by a multitude of biotic and abiotic factors. In addition, its persistence can be influenced by preadaptation before the introduction into the environment. In order to study how preadaptation changes the survival of Salmonella in soil and therefore its potential to colonize the phytosphere, we developed a new medium based on lettuce material [lettuce medium (LM)]. Salmonella enterica serovar Typhimurium strain LT2 was used as a model for Salmonella in this study. LT2 was inoculated into soil microcosms after pregrowth in Luria Bertani (LB) broth or in LM. Survival of LT2 in soil was monitored over 56 days by plate counts and quantification of the Typhimurium-specific gene STM4497 using qPCR in total community DNA for which primers and TaqMan probe were designed in this study. Significantly enhanced persistence was observed for LT2 pregrown in LM compared to LT2 pregrown in LB, indicating a preadaptation effect. Surprisingly, no improved survival could be observed for S. Typhimurium strain 14028s and S. enterica serovar Senftenberg after pregrowth on LM. This indicates a high strain specificity of preadaptation. Results from previous studies suggested that biofilm formation could enhance the survival of human pathogens in various environments and might contribute to enhanced survival on plants. In vitro biofilm assays with several Salmonella strains revealed a strain-specific effect of LM on the biofilm formation. While LM significantly improved the biofilm formation of S. Senftenberg, the biofilm formation of LT2 was better in LB. This indicates that the better survival of LM-pregrown LT2 in soil was not linked to an improved ability to form biofilms but was likely due to other factors. Most importantly, this study showed that the medium used to pregrow Salmonella can influence its survival in soil and its biofilm formation which might influence the fate of Salmonella in soil.

  15. Quantification of contamination of lettuce by GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

    NARCIS (Netherlands)

    Franz, E.; Visser, A.A.; Diepeningen, van A.D.; Klerks, M.M.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2007-01-01

    The primary objective of this study was to determine the possibility of internalization of GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. Typhimurium) strains MAE 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (Lactuca

  16. Quantification of contamination of lettuce by GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

    NARCIS (Netherlands)

    Franz, Eelco; Visser, Anna A; Van Diepeningen, Anne D; Klerks, Michel M; Termorshuizen, Aad J; van Bruggen, Ariena H C

    The primary objective of this study was to determine the possibility of internalization of GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. Typhimurium) strains MAE 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (Lactuca

  17. Distribution of prophages and SGI-1 antibiotic-resistance genes among different Salmonella enterica serovar Typhimurium isolates

    NARCIS (Netherlands)

    Hermans, A.P.H.M.; Beuling, A.M.; Hoek, van A.H.A.M.; Aarts, H.J.M.; Abee, T.; Zwietering, M.H.

    2006-01-01

    Recently, the authors identified Salmonella enterica serovar Typhimurium (S. Typhimurium) definitive type (DT)104-specific sequences of mainly prophage origin by genomic subtractive hybridization. In the present study, the distribution of the prophages identified, ST104 and ST64B, and the novel

  18. Salmonella Typhimurium, Infantis, Derby, and Enteritidis survival in pasty dulce de leche Sobrevivência de Salmonella Typhimurium, Infantis, Derby e Enteritidis em doce de leite pastoso

    Directory of Open Access Journals (Sweden)

    Débora Rodrigues da Silveira

    2012-12-01

    Full Text Available Dulce de leche is a food obtained by concentration and heating of milk with the addition of sucrose. The common practice of opening the dulce de leche containers in retail markets can lead to food contamination by Salmonella. The objective of this study was to evaluate the survivability of Salmonellaenterica subsp. enterica serotypes Typhimurium, Enteritidis, Infantis and Derby in pasty dulce de leche. Aliquots of this sweet were experimentally contaminated with these microorganisms and later analyzed to evaluate microorganism viability after storage for 0, 1, 2, 3, 5, 10, and 20 days. Salmonella was recovered up to the 20th day. These results are a warning about the need to adopt proper sanitary-hygienic measures for handling and packaging this food aiming at food safety.O doce de leite é um alimento obtido por concentração pelo aquecimento do leite com adição de sacarose. O fracionamento do produto no mercado varejista pode levar à contaminação do alimento por Salmonella. O trabalho teve como objetivo testar a capacidade de sobrevivência de Salmonellaenterica subsp. enterica sorotipos Typhimurium, Infantis, Derby e Enteritidis em doce de leite pastoso. Alíquotas de doce de leite foram contaminadas experimentalmente com diferentes cepas de Salmonella e analisadas após 0, 1, 2, 3, 5, 10 e 20 dias de estocagem para verificar a viabilidade do microrganismo. Salmonella pode permanecer viável no doce de leite por 20 dias. Estes resultados são um alerta quanto à necessidade de adoção de medidas higiênico-sanitárias adequadas durante o manuseio e acondicionamento deste alimento com vistas à segurança alimentar.

  19. Comparison of Subtyping Methods for Differentiating Salmonella enterica Serovar Typhimurium Isolates Obtained from Food Animal Sources

    Science.gov (United States)

    Foley, Steven L.; White, David G.; McDermott, Patrick F.; Walker, Robert D.; Rhodes, Bobbie; Fedorka-Cray, Paula J.; Simjee, Shabbir; Zhao, Shaohua

    2006-01-01

    Molecular characterization (e.g., DNA-based typing methods) of Salmonella isolates is frequently employed to compare and distinguish clinical isolates recovered from animals and from patients with food-borne disease and nosocomial infections. In this study, we compared the abilities of different phenotyping and genotyping methods to distinguish isolates of Salmonella enterica serovar Typhimurium from different food animal sources. One hundred twenty-eight S. enterica serovar Typhimurium strains isolated from cattle, pigs, chickens, and turkeys or derived food products were characterized using pulsed-field gel electrophoresis (PFGE), repetitive element PCR (Rep-PCR), multilocus sequence typing (MLST), plasmid profiling, and antimicrobial susceptibility testing. Among the 128 Salmonella isolates tested, we observed 84 Rep-PCR profiles, 86 PFGE patterns, 89 MLST patterns, 36 plasmid profiles, and 38 susceptibility profiles. The molecular typing methods, i.e., PFGE, MLST, and Rep-PCR, demonstrated the best discriminatory power among Salmonella isolates. However, no apparent correlation was evident between the results of one molecular typing method and those of the others, suggesting that a combination of multiple methods is needed to differentiate S. enterica serovar Typhimurium isolates that genetically cluster according to one particular typing method. PMID:17021084

  20. Specific Monoclonal Antibody Overcomes the Salmonella enterica Serovar Typhimurium's Adaptive Mechanisms of Intramacrophage Survival and Replication.

    Directory of Open Access Journals (Sweden)

    Swarmistha Devi Aribam

    Full Text Available Salmonella-specific antibodies play an important role in host immunity; however, the mechanisms of Salmonella clearance by pathogen-specific antibodies remain to be completely elucidated since previous studies on antibody-mediated protection have yielded inconsistent results. These inconsistencies are at least partially attributable to the use of polyclonal antibodies against Salmonella antigens. Here, we developed a new monoclonal antibody (mAb-449 and identified its related immunogen that protected BALB/c mice from infection with Salmonella enterica serovar Typhimurium. In addition, these data indicate that the mAb-449 immunogen is likely a major protective antigen. Using in vitro infection studies, we also analyzed the mechanism by which mAb-449 conferred host protection. Notably, macrophages infected with mAb-449-treated S. Typhimurium showed enhanced pathogen uptake compared to counterparts infected with control IgG-treated bacteria. Moreover, these macrophages produced elevated levels of pro-inflammatory cytokine TNFα and nitric oxide, indicating that mAb-449 enhanced macrophage activation. Finally, the number of intracellular bacteria in mAb-449-activated macrophages decreased considerably, while the opposite was found in IgG-treated controls. Based on these findings, we suggest that, although S. Typhimurium has the potential to survive and replicate within macrophages, host production of a specific antibody can effectively mediate macrophage activation for clearance of intracellular bacteria.

  1. Specific Monoclonal Antibody Overcomes the Salmonella enterica Serovar Typhimurium's Adaptive Mechanisms of Intramacrophage Survival and Replication.

    Science.gov (United States)

    Aribam, Swarmistha Devi; Harada, Tomoyuki; Elsheimer-Matulova, Marta; Iwata, Taketoshi; Kanehira, Katsushi; Hikono, Hirokazu; Matsui, Hidenori; Ogawa, Yohsuke; Shimoji, Yoshihiro; Eguchi, Masahiro

    2016-01-01

    Salmonella-specific antibodies play an important role in host immunity; however, the mechanisms of Salmonella clearance by pathogen-specific antibodies remain to be completely elucidated since previous studies on antibody-mediated protection have yielded inconsistent results. These inconsistencies are at least partially attributable to the use of polyclonal antibodies against Salmonella antigens. Here, we developed a new monoclonal antibody (mAb)-449 and identified its related immunogen that protected BALB/c mice from infection with Salmonella enterica serovar Typhimurium. In addition, these data indicate that the mAb-449 immunogen is likely a major protective antigen. Using in vitro infection studies, we also analyzed the mechanism by which mAb-449 conferred host protection. Notably, macrophages infected with mAb-449-treated S. Typhimurium showed enhanced pathogen uptake compared to counterparts infected with control IgG-treated bacteria. Moreover, these macrophages produced elevated levels of pro-inflammatory cytokine TNFα and nitric oxide, indicating that mAb-449 enhanced macrophage activation. Finally, the number of intracellular bacteria in mAb-449-activated macrophages decreased considerably, while the opposite was found in IgG-treated controls. Based on these findings, we suggest that, although S. Typhimurium has the potential to survive and replicate within macrophages, host production of a specific antibody can effectively mediate macrophage activation for clearance of intracellular bacteria.

  2. PHYSICAL AND MICROBIOLOGICALQUALITYOFOPAQUE, SANITIZED, AND CHILLED QUAIL EGGS EXPERIMENTALLY CONTAMINATED WITH Salmonella enteric SER. TYPHIMURIUM

    Directory of Open Access Journals (Sweden)

    Maria Juliana Ribeiro Lacerda

    2016-01-01

    Full Text Available The objective of this study was to verify the physical, chemical and microbiological quality of Japanese quail eggs artificially contaminated with Salmonella enterica ser. Typhimurium. The eggs were sanitized and stored at different temperatures (between 5 and 25 ºC for 27 days. We used 768 eggs with opaque shells, typical pigments of the species, and average weight of 11 g. The experimental design was completely randomized in a 2x2x2 factorial arrangement (contamination x sanitation x cooling with six replications and one egg per experimental unit. The eggs were contaminated by handling with 1.5 x 105 colony forming unit (CFU of Salmonella. Typhimurium / mL and sanitized according to the treatments with a 5 ppm Cl solution. The data were subjected to analysis of variance and t test. Bacterial contamination has damaged the egg weight, Haugh unit, yolk index and albumen, and pH of yolk and albumen, from 18 days of storage. The egg storage time and storage temperature affected the internal quality of quail eggs in all variables. The worst internal quality was observed in eggs stored at 25 ºC. The sanitation and cooling reduced the growth of Salmonella in contaminated eggs. Eggs in opaque shell, when not refrigerated, should be consumed within 18 days after laying. Keywords: opaque shell; quail eggs; Salmonella Typhimurium; sanitization; storage.

  3. DETERMINACIÓN DE Salmonella Typhimurium EN COMPOST INOCULADO ARTIFICIALMENTE EMPLEADO EN UN CULTIVO DE LECHUGA Salmonella Typhimurium determination in compost artificially inoculated in a lettuce crop

    Directory of Open Access Journals (Sweden)

    DIANA MARCELA RODRÍGUEZ

    Full Text Available Salmonella enterica serovariedad Typhimurium, se ha asociado a brotes por el consumo de frutas y vegetales contaminadas a partir de agua de riego, manipuladores, bioabono y suelo. En esta investigación se inoculó artificialmente un bioabono aplicado a un cultivo de lechuga para determinar la capacidad de transferencia a las plantas, así como establecer el efecto del uso de cubiertas de polietileno en la protección del cultivo frente a este patógeno. Para ello, se utilizaron plántulas de lechuga de ocho semanas y se establecieron cuatro tratamientos y dos controles: T1 y T2, con y sin cubierta de polietileno respectivamente, contenían una concentración de Salmonella enterica Serovariedad Typhimurium ATCC 13176 inoculada en el compost en concentración de 0,04 mo/g, T3 y T4 con y sin cubierta de polietileno respectivamente con 100 mo/g de compost y finalmente C1 y C2 con y sin cubierta pero sin inoculación. El seguimiento del microorganismo en suelo se realizó durante las ocho semanas del cultivo, mediante la técnica de NMP/4 g (EPA, 2006 al cabo de este tiempo se evaluó el total de plantas cultivadas mediante la misma técnica. Se determinó que Salmonella enterica serovariedad Typhimurium ATCC 13176 se transmite a la lechuga, a partir del bioabono contaminado (OR=2,53 sin importar la concentración inicial del microorganismo en el bioabono; así mismo se encontró que existe asociación entre la contaminación y la condición de cubierta del cultivo (p=0,002. Por otra parte, al analizar las raíces no se encontró asociación de transmisión.Salmonella enterica serovariedad Typhimurium, has been associated with outbreaks because of the ingestion of fruits and vegetables and those outbreaks have been related due to contamination sources like irrigation water, farm workers influence and the soil itself. In this investigation it was artificially inoculated in a compost and later applied to a lettuce crop, in order to determine the

  4. The anti-infective activity of punicalagin against Salmonella enterica subsp. enterica serovar typhimurium in mice.

    Science.gov (United States)

    Li, Guanghui; Feng, Yuqing; Xu, Yunfeng; Wu, Qian; Han, Qi'an; Liang, Xiujun; Yang, Baowei; Wang, Xin; Xia, Xiaodong

    2015-07-01

    Punicalagin, a major bioactive component of pomegranate peel, has been proven to have antioxidant, antiviral, anti-apoptosis, and hepatoprotective properties. The aim of this study was to investigate the anti-infective activity of punicalagin in a mouse model. C57BL/6 mice were initially challenged with Salmonella enterica subsp. enterica serovar typhimurium (S. typhimurium) and then treated with punicalagin. Food and water consumption and body weight were recorded daily. On day 8 post infection, the mice were sacrificed to examine pathogen counts in tissues, hematological parameters, cytokine levels, and histological changes. Compared to mice only infected with S. typhimurium, punicalagin-treated mice had more food consumption and less weight loss. A higher survival rate and lower counts of viable S. typhimurium in feces, liver, spleen, and kidney were found in the punicalagin-treated mice. The enzyme linked immunosorbent assay showed that the levels of IL-6, IL-10, and IFN-γ in serum and the spleen and TNF-α in serum, the spleen and the liver were reduced by punicalagin. Moreover, more neutrophils and higher neutrophil-to-mononuclear cell ratios in the punicalagin-treated mice were observed. Histological examination showed that punicalagin protected cells in the liver and spleen from hemorrhagic necrosis. It is concluded that punicalagin has a beneficial effect against S. typhimurium infection in mice. The anti-infective properties, together with other nutritionally beneficial effects, make punicalagin a promising supplement in human food or animal feeds to prevent disease associated with S. typhimurium.

  5. Behaviour of Salmonella Typhimurium during production and storage of artisan water buffalo mozzarella cheese

    Directory of Open Access Journals (Sweden)

    Roberto Rosmini

    2012-07-01

    Full Text Available Water buffalo mozzarella cheese (WBMC is a fresh pasta filata cheese produced from whole chilled buffalo milk. Although pasteurization of milk and the use of defined starter cultures are recommended, traditional technology involving the use of unpasteurized milk and natural whey cultures is still employed for WBMC production in Italy. The aim of this study were to assess the behaviour of Salmonella Typhimurium during the production of artisan water buffalo mozzarella cheese and during its shelf life under different temperature conditions. Raw milk was inoculated with S. Typhimurium and the evolution of S. Typhimurium count during production and shelf life was monitored. In artisan WBMC production technology S. Typhimurium multiplied in the curd during ripening, but its growth rate expressed in log CFU/g/h was lower than the growth rate reported by theoretical predictions. Stretching proved to be a process with good repeatability and able to reduce S. Typhimurium contamination by 5.5 Log CFU/g. The intrinsic characteristics of traditional WBMC proved to be unable to obstacolate the growth of S. Typhimurium during storage in the case of thermal abuse. Control of raw milk contamination and a proper refrigeration temperature are key factors in reducing the risk for consumers.

  6. Immunochromatographic strip assay for the rapid and sensitive detection of Salmonella Typhimurium in artificially contaminated tomato samples.

    Science.gov (United States)

    Shukla, Shruti; Leem, Hyerim; Lee, Jong-Suk; Kim, Myunghee

    2014-06-01

    This study was designed to confirm the applicability of a liposome-based immunochromatographic assay for the rapid detection of Salmonella enterica subsp. enterica serovar Typhimurium (Salmonella Typhimurium) in artificially contaminated tomato samples. To determine the detection limit and pre-enrichment incubation time (10, 12, and 18 h pre-enrichment in 1% buffered peptone water), the tests were performed with different cell numbers of Salmonella Typhimurium (3 × 10(0), 3 × 10(1), 3 × 10(2), and 3 × 10(3) CFU·mL(-1)) inoculated into 25 g of crushed tomato samples. The assay was able to detect as few as 30 Salmonella Typhimurium cells per 25 g of tomato samples (1.2 cells·g(-1)) after 12 h pre-enrichment incubation. Moreover, when the developed assay was compared with traditional morphological and biochemical culture-based methods as well as colloidal gold nanoparticle-based commercial test strips, the developed assay yielded positive results for the detection of Salmonella Typhimurium within a shorter period time. These findings confirm that the developed assay may have practical application for the sensitive detection of Salmonella Typhimurium in various food samples, including raw vegetables, with a relatively low detection limit and shorter analysis time.

  7. Effect of the oyster contaminated in Salmonella typhimurium and Escherichia coli; Efecto del ostion contaminado en Salmonella typhimurium y Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Brena V, M

    1992-08-15

    In this work the effect of the oyster contaminated in the species of bacteria better studied by its genetic composition these are the Salmonella typhimurium and the Escherichia coli and that its have been starting point for later radiobiological studies in superior organisms. Of this its have arisen two general lines. The research about the genotoxic effect of substances or mixtures in bacteria with the collaboration of the groups of Drosophila and X-ray Fluorescence analysis and on the other hand the study of the low doses of radiation also in bacteria. It is also treated the topic about the genetic effect of aromatic hydrocarbons in different biological systems. (Author)

  8. Loss of Multicellular Behavior in Epidemic African Nontyphoidal Salmonella enterica Serovar Typhimurium ST313 Strain D23580.

    Science.gov (United States)

    Singletary, Larissa A; Karlinsey, Joyce E; Libby, Stephen J; Mooney, Jason P; Lokken, Kristen L; Tsolis, Renée M; Byndloss, Mariana X; Hirao, Lauren A; Gaulke, Christopher A; Crawford, Robert W; Dandekar, Satya; Kingsley, Robert A; Msefula, Chisomo L; Heyderman, Robert S; Fang, Ferric C

    2016-03-01

    Nontyphoidal Salmonella enterica serovar Typhimurium is a frequent cause of bloodstream infections in children and HIV-infected adults in sub-Saharan Africa. Most isolates from African patients with bacteremia belong to a single sequence type, ST313, which is genetically distinct from gastroenteritis-associated ST19 strains, such as 14028s and SL1344. Some studies suggest that the rapid spread of ST313 across sub-Saharan Africa has been facilitated by anthroponotic (person-to-person) transmission, eliminating the need for Salmonella survival outside the host. While these studies have not ruled out zoonotic or other means of transmission, the anthroponotic hypothesis is supported by evidence of extensive genomic decay, a hallmark of host adaptation, in the sequenced ST313 strain D23580. We have identified and demonstrated 2 loss-of-function mutations in D23580, not present in the ST19 strain 14028s, that impair multicellular stress resistance associated with survival outside the host. These mutations result in inactivation of the KatE stationary-phase catalase that protects high-density bacterial communities from oxidative stress and the BcsG cellulose biosynthetic enzyme required for the RDAR (red, dry, and rough) colonial phenotype. However, we found that like 14028s, D23580 is able to elicit an acute inflammatory response and cause enteritis in mice and rhesus macaque monkeys. Collectively, these observations suggest that African S. Typhimurium ST313 strain D23580 is becoming adapted to an anthroponotic mode of transmission while retaining the ability to infect and cause enteritis in multiple host species. The last 3 decades have witnessed an epidemic of invasive nontyphoidal Salmonella infections in sub-Saharan Africa. Genomic analysis and clinical observations suggest that the Salmonella strains responsible for these infections are evolving to become more typhoid-like with regard to patterns of transmission and virulence. This study shows that a prototypical

  9. Iron acquisition pathways and colonization of the inflamed intestine by Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Costa, Luciana F; Mol, Juliana P S; Silva, Ana Patricia C; Macêdo, Auricélio A; Silva, Teane M A; Alves, Geraldo E S; Winter, Sebastian; Winter, Maria G; Velazquez, Eric M; Byndloss, Mariana X; Bäumler, Andreas J; Tsolis, Renée M; Paixão, Tatiane A; Santos, Renato L

    2016-12-01

    Salmonella enterica serotype Typhimurium is able to expand in the lumen of the inflamed intestine through mechanisms that have not been fully resolved. Here we utilized streptomycin-pretreated mice and dextran sodium sulfate (DSS)-treated mice to investigate how pathways for S. Typhimurium iron acquisition contribute to pathogen expansion in the inflamed intestine. Competitive infection with an iron uptake-proficient S. Typhimurium strain and mutant strains lacking tonB feoB, feoB, tonB or iroN in streptomycin pretreated mice demonstrated that ferric iron uptake requiring IroN and TonB conferred a fitness advantage during growth in the inflamed intestine. However, the fitness advantage conferred by ferrous iron uptake mechanisms was independent of inflammation and was only apparent in models where the normal microbiota composition had been disrupted by antibiotic treatment. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Tetracycline consumption and occurrence of tetracycline resistance in Salmonella typhimurium phage types from Danish pigs

    DEFF Research Database (Denmark)

    Emborg, Hanne-Dorthe; Vigre, Håkan; Jensen, Vibeke Frøkjær

    2007-01-01

    The aims of the present study were to investigate at the farm-owner level the effect of prescribed tetracycline consumption in pigs and different Salmonella Typhimurium phage types on the probability that the S. Typhimurium was resistant to tetracycline. In this study, 1,307 isolates were included......, originating from 877 farm owners, and data were analyzed using logistic regression. The analysis showed that both the S. Typhimurium phage type (p resistance. In particular, the phage type...... was strongly associated with tetracycline resistance. A further analysis of data from the Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP) indicates that the tetracycline-susceptible phage types only slowly become tetracycline resistant, although tetracycline consumption...

  11. Microevolution of Monophasic Salmonella Typhimurium during Epidemic, United Kingdom, 2005-2010.

    Science.gov (United States)

    Petrovska, Liljana; Mather, Alison E; AbuOun, Manal; Branchu, Priscilla; Harris, Simon R; Connor, Thomas; Hopkins, K L; Underwood, A; Lettini, Antonia A; Page, Andrew; Bagnall, Mary; Wain, John; Parkhill, Julian; Dougan, Gordon; Davies, Robert; Kingsley, Robert A

    2016-04-01

    Microevolution associated with emergence and expansion of new epidemic clones of bacterial pathogens holds the key to epidemiologic success. To determine microevolution associated with monophasic Salmonella Typhimurium during an epidemic, we performed comparative whole-genome sequencing and phylogenomic analysis of isolates from the United Kingdom and Italy during 2005-2012. These isolates formed a single clade distinct from recent monophasic epidemic clones previously described from North America and Spain. The UK monophasic epidemic clones showed a novel genomic island encoding resistance to heavy metals and a composite transposon encoding antimicrobial drug resistance genes not present in other Salmonella Typhimurium isolates, which may have contributed to epidemiologic success. A remarkable amount of genotypic variation accumulated during clonal expansion that occurred during the epidemic, including multiple independent acquisitions of a novel prophage carrying the sopE gene and multiple deletion events affecting the phase II flagellin locus. This high level of microevolution may affect antigenicity, pathogenicity, and transmission.

  12. Microevolution of Monophasic Salmonella Typhimurium during Epidemic, United Kingdom, 2005–2010

    Science.gov (United States)

    Petrovska, Liljana; Mather, Alison E.; AbuOun, Manal; Branchu, Priscilla; Harris, Simon R.; Connor, Thomas; Hopkins, K.L.; Underwood, A.; Lettini, Antonia A.; Page, Andrew; Bagnall, Mary; Wain, John; Parkhill, Julian; Dougan, Gordon; Davies, Robert

    2016-01-01

    Microevolution associated with emergence and expansion of new epidemic clones of bacterial pathogens holds the key to epidemiologic success. To determine microevolution associated with monophasic Salmonella Typhimurium during an epidemic, we performed comparative whole-genome sequencing and phylogenomic analysis of isolates from the United Kingdom and Italy during 2005–2012. These isolates formed a single clade distinct from recent monophasic epidemic clones previously described from North America and Spain. The UK monophasic epidemic clones showed a novel genomic island encoding resistance to heavy metals and a composite transposon encoding antimicrobial drug resistance genes not present in other Salmonella Typhimurium isolates, which may have contributed to epidemiologic success. A remarkable amount of genotypic variation accumulated during clonal expansion that occurred during the epidemic, including multiple independent acquisitions of a novel prophage carrying the sopE gene and multiple deletion events affecting the phase II flagellin locus. This high level of microevolution may affect antigenicity, pathogenicity, and transmission. PMID:26982594

  13. The transcriptional landscape and small RNAs of Salmonella enterica serovar Typhimurium

    DEFF Research Database (Denmark)

    Kröger, Carsten; Dillon, Shane C.; Cameron, Andrew D. S.

    2012-01-01

    for Salmonella infection, but basic genetic information such as the global locations of transcription start sites (TSSs) has been lacking. We combined three RNA-sequencing techniques and two sequencing platforms to generate a robust picture of transcription in S. Typhimurium. Differential RNA sequencing...... expresses 140 small regulatory RNAs (sRNAs) at early stationary phase, including 60 newly identified sRNAs. Almost half of the experimentally verified sRNAs were found to be unique to the Salmonella genus, and...... identified 1,873 TSSs on the chromosome of S. Typhimurium SL1344 and 13% of these TSSs initiated antisense transcripts. Unique findings include the TSSs of the virulence regulators phoP, slyA, and invF. Chromatin immunoprecipitation revealed that RNA polymerase was bound to 70% of the TSSs, and two...

  14. Structure of the ribosomal interacting GTPase YjeQ from the enterobacterial species Salmonella typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, C. E. [Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Johnson, C.; Lamb, H. K. [Institute of Cell and Molecular Biosciences, Catherine Cookson Building, Medical School, Framlington Place, Newcastle University, Newcastle-upon-Tyne NE2 4HH (United Kingdom); Lockyer, M. [Arrow Therapeutics Ltd, Britannia House, Trinity Street, Borough, London SE1 1DA (United Kingdom); Charles, I. G. [The Wolfson Institute for Biomedical Research, The Cruciform Building, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hawkins, A. R. [Institute of Cell and Molecular Biosciences, Catherine Cookson Building, Medical School, Framlington Place, Newcastle University, Newcastle-upon-Tyne NE2 4HH (United Kingdom); Stammers, D. K., E-mail: daves@strubi.ox.ac.uk [Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom)

    2007-11-01

    The X-ray crystal structure of the GTPase YjeQ from S. typhimurium is presented and compared with those of orthologues from T. maritima and B. subtilis. The YjeQ class of P-loop GTPases assist in ribosome biogenesis and also bind to the 30S subunit of mature ribosomes. YjeQ ribosomal binding is GTP-dependent and thought to specifically direct protein synthesis, although the nature of the upstream signal causing this event in vivo is as yet unknown. The attenuating effect of YjeQ mutants on bacterial growth in Escherichia coli makes it a potential target for novel antimicrobial agents. In order to further explore the structure and function of YjeQ, the isolation, crystallization and structure determination of YjeQ from the enterobacterial species Salmonella typhimurium (StYjeQ) is reported. Whilst the overall StYjeQ fold is similar to those of the previously reported Thematoga maritima and Bacillus subtilis orthologues, particularly the GTPase domain, there are larger differences in the three OB folds. Although the zinc-finger secondary structure is conserved, significant sequence differences alter the nature of the external surface in each case and may reflect varying signalling pathways. Therefore, it may be easier to develop YjeQ-specific inhibitors that target the N- and C-terminal regions, disrupting the metabolic connectivity rather than the GTPase activity. The availability of coordinates for StYjeQ will provide a significantly improved basis for threading Gram-negative orthologue sequences and in silico compound-screening studies, with the potential for the development of species-selective drugs.

  15. Thioridazine protects the mouse from a virulent infection by Salmonella enterica serovar Typhimurium 74

    DEFF Research Database (Denmark)

    Dasgupta, Asish; Mukherjee, Sayanti; Chaki, Shaswati

    2010-01-01

    When administered to mice at doses of 100microg/mouse and 200microg/mouse, thioridazine (TDZ) significantly protected animals from the lethality produced by a virulent strain of Salmonella enterica serovar Typhimurium and reduced the number of bacteria retrieved from the spleen, liver and heart...... blood. The protection conferred by TDZ against a virulent Salmonella infection is hypothesised to be due to a reduction in the 55kDa virulence protein of the outer membrane of the organism, as this protein is almost totally absent when the organism is exposed to the phenothiazine. It is further...

  16. Disruption of type III secretion in Salmonella enterica serovar Typhimurium by external guide sequences

    OpenAIRE

    McKinney, Jeffrey S.; Zhang, Haifeng; Kubori, Tomoko; Galán, Jorge E.; Altman, Sidney

    2004-01-01

    The type III secretion system involved in Salmonella enterica serovar Typhimurium invasion of host cells has been disrupted using inducibly expressed oligonucleotide external guide sequences (EGSs) complementary to invB or invC mRNA. These EGSs direct single site cleavage in these mRNAs by endogenous RNase P, and their expression in Salmonella results in invC mRNA and InvC protein depletion, decreased type III secretion and interference with host cell invasion. Comparison of these effects wit...

  17. Biocontrol of Salmonella Typhimurium in RTE foods with the virulent bacteriophage FO1-E2.

    Science.gov (United States)

    Guenther, Susanne; Herzig, Oliver; Fieseler, Lars; Klumpp, Jochen; Loessner, Martin J

    2012-03-01

    Foodborne Salmonella infections are a major public health concern worldwide. Bacteriophages offer highly specific and effective biocontrol of such pathogens. We evaluated the broad host range, virulent phage FO1-E2 for reduction of Salmonella Typhimurium in different RTE foods. Samples were spiked with 1×10³ Salmonella cells and treated with 3×10⁸ pfu/g phage, and incubated for 6 days at 8 °C or 15 °C. At 8 °C, no viable cells remained following FO1-E2 application, corresponding to a more than 3 log₁₀ unit reduction. At 15 °C, application of phage lowered S. Typhimurium counts by 5 log units on turkey deli meat and in chocolate milk, and by 3 logs on hot dogs and in seafood. In egg yolk, an effect was observed only after 2 days, but not after 6 days. Phage particles retained their infectivity, although they were readily immobilized by the food matrix, resulting in loss of their ability to diffuse and infect target cells. At the end of the incubation period, phage-resistant Salmonella strains appeared which, however, were not able to compensate for the initial killing effect. Altogether, our data show that virulent phages such as FO1-E2 offer an effective biocontrol measure for Salmonella in foods. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. COORDINATED VIRULENCE FACTORS OF ZOONOTIC PATHOGEN Salmonella Typhimurium ASSOCIATED WITH SYSTEMIC DISEASE

    Directory of Open Access Journals (Sweden)

    Ermin Schadich

    2013-08-01

    Full Text Available  The pivotal virulence factors of foodborne zoonotic pathogen Salmonella enterica serotype Typhimurium associated with pathogenesis of systemic disease of humans and mice are the effectors of type three secretion systems. They are encoded by genes located on two different gene clusters named Salmonella pathogenicity island 1 and 2 (SPI-1 and SPI-2 and Salmonella plasmid virulence locus whose expressions are coordinated by regulatory networks in spatial and temporal manners. Secretion of the SPI-1 effectors required for bacterial internalization into specific compartments called Salmonella- containing vacuole (SCV of infected intestinal epithelial cells, is induced by environmental conditions via Hil transcription factors network. Secretion of SPI-2 and plasmid effectors required for bacterial survival inside of the SCVs of these cells and subsequently infected phagocytic cells, systemic spread, immunosuppression and cytotoxicity, is coordinated by broader regulatory network with the two response regulators, SsrB and SlyA, as the terminal regulators that integrate multiple environmental signals. Key words: Salmonella Typhimurium, effectors, virulence, systemic disease

  19. Molecular detection assay of five Salmonella serotypes of public interest: Typhimurium, Enteritidis, Newport, Heidelberg, and Hadar.

    Science.gov (United States)

    Bugarel, M; Tudor, A; Loneragan, G H; Nightingale, K K

    2017-03-01

    Foodborne illnesses due to Salmonella represent an important public-health concern worldwide. In the United States, a majority of Salmonella infections are associated with a small number of serotypes. Furthermore, some serotypes that are overrepresented among human disease are also associated with multi-drug resistance phenotypes. Rapid detection of serotypes of public-health concern might help reduce the burden of salmonellosis cases and limit exposure to multi-drug resistant Salmonella. We developed a two-step real-time PCR-based rapid method for the identification and detection of five Salmonella serotypes that are either overrepresented in human disease or frequently associated with multi-drug resistance, including serotypes Enteritidis, Typhimurium, Newport, Hadar, and Heidelberg. Two sets of four markers were developed to detect and differentiate the five serotypes. The first set of markers was developed as a screening step to detect the five serotypes; whereas, the second set was used to further distinguish serotypes Heidelberg, Newport and Hadar. The utilization of these markers on a two-step investigation strategy provides a diagnostic specificity of 97% for the detection of Typhimurium, Enteritidis, Heidelberg, Infantis, Newport and Hadar. The diagnostic sensitivity of the detection makers is >96%. The availability of this two-step rapid method will facilitate specific detection of Salmonella serotypes that contribute to a significant proportion of human disease and carry antimicrobial resistance. Published by Elsevier B.V.

  20. Use of acetic and citric acids to control Salmonella Typhimurium in tahini (sesame paste).

    Science.gov (United States)

    Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Shaker, Reyad R; Zein Elabedeen, Noor; Jaradat, Ziad W; Abushelaibi, Aisha; Holley, Richard A

    2014-09-01

    Since tahini and its products have been linked to Salmonella illness outbreaks and product recalls in recent years, this study assessed the ability of Salmonella Typhimurium to survive or grow in commercial tahini and when hydrated (10% w/v in water), treated with 0.1%-0.5% acetic or citric acids, and stored at 37, 21 and 10 °C for 28 d. S. Typhimurium survived in commercial tahini up to 28 d but was reduced in numbers from 1.7 to 3.3 log10 CFU/ml. However, in the moist or hydrated tahini, significant growth of S. Typhimurium occurred at the tested temperatures. Acetic and citric acids at ≤0.5% reduced S. Typhimurium by 2.7-4.8 log10 CFU/ml and 2.5-3.8 log10 CFU/ml, respectively, in commercial tahini at 28 d. In hydrated tahini the organic acids were more effective. S. Typhimurium cells were not detected in the presence of 0.5% acetic acid after 7 d or with 0.5% citric acid after 21 d at the tested temperatures. The ability of S. Typhimurium to grow or survive in commercial tahini and products containing hydrated tahini may contribute to salmonellosis outbreaks; however, use of acetic and citric acids in ready-to-eat foods prepared from tahini can significantly minimize the risk associated with this pathogen. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Epidemiology of a Salmonella enterica subsp. Enterica serovar Typhimurium strain associated with a songbird outbreak.

    Science.gov (United States)

    Blehert, David S.; Hernandez, Sonia M.; Keel, Kevin; Sanchez, Susan; Trees, Eija; ,

    2012-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

  2. Impact of phytopathogen infection and extreme weather stress on internalization of Salmonella Typhimurium in lettuce.

    Science.gov (United States)

    Ge, Chongtao; Lee, Cheonghoon; Nangle, Ed; Li, Jianrong; Gardner, David; Kleinhenz, Matthew; Lee, Jiyoung

    2014-01-03

    Internalization of human pathogens, common in many types of fresh produce, is a threat to human health since the internalized pathogens cannot be fully inactivated/removed by washing with water or sanitizers. Given that pathogen internalization can be affected by many environmental factors, this study was conducted to investigate the influence of two types of plant stress on the internalization of Salmonella Typhimurium in iceberg lettuce during pre-harvest. The stresses were: abiotic (water stress induced by extreme weather events) and biotic (phytopathogen infection by lettuce mosaic virus [LMV]). Lettuce with and without LMV infection were purposefully contaminated with green fluorescence protein-labeled S. Typhimurium on the leaf surfaces. Lettuce was also subjected to water stress conditions (drought and storm) which were simulated by irrigating with different amounts of water. The internalized S. Typhimurium in the different parts of the lettuce were quantified by plate count and real-time quantitative PCR and confirmed with a laser scanning confocal microscope. Salmonella internalization occurred under the conditions outlined above; however internalization levels were not significantly affected by water stress alone. In contrast, the extent of culturable S. Typhimurium internalized in the leafy part of the lettuce decreased when infected with LMV under water stress conditions and contaminated with high levels of S. Typhimurium. On the other hand, LMV-infected lettuce showed a significant increase in the levels of culturable bacteria in the roots. In conclusion, internalization was observed under all experimental conditions when the lettuce surface was contaminated with S. Typhimurium. However, the extent of internalization was only affected by water stress when lettuce was infected with LMV. © 2013.

  3. Mass mortality of Eurasian Tree Sparrows (Passer montanus) from Salmonella Typhimurium dt40 in Japan, winter 2008-09.

    Science.gov (United States)

    Fukui, Daisuke; Takahashi, Katsumi; Kubo, Midori; Une, Yumi; Kato, Yukio; Izumiya, Hidemasa; Teraoka, Hiroki; Asakawa, Mitsuhiko; Yanagida, Kazumi; Bando, Gen

    2014-07-01

    An outbreak of salmonellosis in wild passerines caused mass mortality of Eurasian Tree Sparrows (Passer montanus) in Hokkaido, Japan, 2005-06; however, the etiology was poorly understood. In winter 2008-09, sparrow mortality again occurred in Hokkaido, and 202 deaths in 100 incidents at 94 sites were reported. We conducted a comprehensive investigation to evaluate the cause and impact on sparrow populations. We collected 26 carcasses at 13 sites, including a zoological park. In addition, Salmonella screening of zoo animals was conducted as a biosecurity measure. Salmonella Typhimurium was isolated from multiple organs in all examined sparrows; they were diagnosed with septicemic salmonellosis. Eleven sites (85%) were related to wild bird feeding and six of eight sparrow fecal samples, including from the zoo, were S. Typhimurium-positive. No infection was detected in zoo animals. Isolates belonged to three phage types: DT40 (88%), DT110 (8%), and DT120 (4%). Pulsed-field gel electrophoresis patterns were the same in all isolates, regardless of phage type. Biochemical characteristics and antibiotic-resistance profiles of DT40 were similar in all isolates, indicating a single origin. The mortality was likely associated with that in 2005-06 because the isolates had the same profiles. Tissue levels of sodium, calcium, and magnesium (the main components of chemical deicer suspected to be the major cause of poisoning deaths in 2005-06 mortality) were not higher in the affected sparrows. We conclude that an emerging epidemic infection with S. Typhimurium DT40 related to bird feeding was the cause of sparrow mortality in 2008-09 and suggest that this causative strain is host-adapted to sparrows in Japan. The mortality might have had some impact on the local population, but its influence was limited.

  4. Oral administration of a probiotic Lactobacillus modulates cytokine production and TLR expression improving the immune response against Salmonella enterica serovar Typhimurium infection in mice

    Directory of Open Access Journals (Sweden)

    Perdigón Gabriela

    2011-08-01

    Full Text Available Abstract Background Diarrheal infections caused by Salmonella, are one of the major causes of childhood morbidity and mortality in developing countries. Salmonella causes various diseases that range from mild gastroenteritis to enteric fever, depending on the serovar involved, infective dose, species, age and immune status of the host. Probiotics are proposed as an attractive alternative possibility in the prevention against this pathogen infection. Previously we demonstrated that continuous Lactobacillus casei CRL 431 administration to BALB/c mice before and after challenge with Salmonella enterica serovar Typhimurium (S. Typhimurium decreased the severity of Salmonella infection. The aim of the present work was to deep into the knowledge about how this probiotic bacterium exerts its effect, by assessing its impact on the expression and secretion of pro-inflammatory (TNFα, IFNγ and anti-inflammatory (IL-10 cytokines in the inductor and effector sites of the gut immune response, and analyzing toll-like receptor (TLR2, TLR4, TLR5 and TLR9 expressions in both healthy and infected mice. Results Probiotic administration to healthy mice increased the expression of TLR2, TLR4 and TLR9 and improved the production and secretion of TNFα, IFNγ and IL-10 in the inductor sites of the gut immune response (Peyer's patches. Post infection, the continuous probiotic administration, before and after Salmonella challenge, protected the host by modulating the inflammatory response, mainly in the immune effector site of the gut, decreasing TNFα and increasing IFNγ, IL-6 and IL-10 production in the lamina propria of the small intestine. Conclusions The oral administration of L. casei CRL 431 induces variations in the cytokine profile and in the TLRs expression previous and also after the challenge with S. Typhimurium. These changes show some of the immune mechanisms implicated in the protective effect of this probiotic strain against S. Typhimurium, providing

  5. Efficacy of solar disinfection of Escherichia coli, Shigella flexneri, Salmonella Typhimurium and Vibrio cholerae.

    Science.gov (United States)

    Berney, M; Weilenmann, H-U; Simonetti, A; Egli, T

    2006-10-01

    To determine the efficacy of solar disinfection (SODIS) for enteric pathogens and to test applicability of the reciprocity law. Resistance to sunlight at 37 degrees C based on F99 values was in the following order: Salmonella Typhimurium>Escherichia coli>Shigella flexneri>Vibrio cholerae. While F90 values of Salm. Typhimurium and E. coli were similar, F99 values differed by 60% due to different inactivation curve shapes. Efficacy seemed not to be dependent on fluence rate for E. coli stationary cells. Sensitivity to mild heat was observed above a temperature of 45 degrees C for E. coli, Salm. Typhimurium and Sh. flexneri, while V. cholerae was already susceptible above 40 degrees C. Salmonella Typhimurium was the most resistant and V. cholerae the least resistant enteric strain. The reciprocity law is applicable for stationary E. coli cells irradiated with sunlight or artificial sunlight. Escherichia coli might not be the appropriate indicator bacterium to test the efficacy of SODIS on enteric bacteria and the physiological response to SODIS might be different among enteric bacteria. The applicability of the reciprocity law indicates that fluence rate plays a secondary role in SODIS efficacy. Stating inactivation efficacy with T90 or F90 values without showing original data is inadequate for SODIS studies.

  6. Elimination of Salmonella enterica serovar Typhimurium in artificially contaminated eggs through correct cooking and frying procedures

    Directory of Open Access Journals (Sweden)

    Geovana Dagostim Savi

    2011-06-01

    Full Text Available Salmonellosis is a serious foodborne disease associated with the presence of bacteria in eggs or foods containing raw eggs. However, the use of appropriate procedures of cooking and frying can eliminate this contamination. There are few studies on the elimination of contamination of Salmonella in hens' eggs through typical frying procedures, especially for Salmonella enterica serovar Typhimurium (or S. typhimurium. The aim of this study was to determine the appropriate conditions for cooking and frying hens' eggs artificially contaminated with S. typhimurium, making them free of bacterial contamination. Hens' eggs were artificially contaminated with S. typhimurium and subjected to various processes of cooking, frying and food preparation. It was observed that the minimum time necessary to eliminate contamination through cooking procedures is 5 minutes after the water starts boiling, and also that, cooking in the microwave oven complete eliminates the bacterial contamination. When the eggs were fried on both sides, keeping the yolk hard, a complete bacterial elimination was observed. Mayonnaise prepared with vinegar presented a decrease in bacterial colonies when compared mayonese prepared with lemon.

  7. Salmonella Typhimurium, Infantis, Derby, and Enteritidis survival in pasty dulce de leche

    OpenAIRE

    Silveira,Débora Rodrigues da; Lopes,Nathalie Almeida; Gonzalez,Helenice de Lima; Timm,Cláudio Dias

    2012-01-01

    Dulce de leche is a food obtained by concentration and heating of milk with the addition of sucrose. The common practice of opening the dulce de leche containers in retail markets can lead to food contamination by Salmonella. The objective of this study was to evaluate the survivability of Salmonellaenterica subsp. enterica serotypes Typhimurium, Enteritidis, Infantis and Derby in pasty dulce de leche. Aliquots of this sweet were experimentally contaminated with these microorganisms and later...

  8. An Outbreak of Salmonella Typhimurium infections in Denmark, Norway and Sweden, 2008

    DEFF Research Database (Denmark)

    Bruun, T; Sørensen, Gitte; Forshell, L P

    2009-01-01

    In November-December 2008, Norway and Denmark independently identified outbreaks of Salmonella Typhimurium infections characterised in the multiple-locus variable number of tandem repeats analysis (MLVA) by a distinct profile. Outbreak investigations were initiated independently in the two countr......-border outbreaks. Differences in legal requirements for food safety in neighbouring countries may be a challenge in terms of communication with consumers in areas where cross-border shopping is common....

  9. The plasmid pattern as an epidemiologic tool for Salmonella typhimurium epidemics: comparison with the lysotype.

    Science.gov (United States)

    Brunner, F; Margadant, A; Peduzzi, R; Piffaretti, J C

    1983-07-01

    In the study of a limited epidemic of Salmonella typhimurium infections, the plasmid content (pattern) of bacteria was used as an epidemiologic tool outside the hospital environment. Comparisons were made with lysotyping, resistance pattern determination (14 antibiotics), and biotyping. Plasmid pattern determination was found to be as useful and accurate as lysotyping, whereas resistance pattern determination was of more limited interest. However, in this report biotyping was of no use.

  10. Evaluation of alternariol and alternariol methyl ether for mutagenic activity in Salmonella typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    Davis, V.M.; Stack, M.E. (Food and Drug Administration, Washington, DC (United States))

    1994-10-01

    Alternariol and alternariol methyl ether were tested in the Ames Salmonella typhimurium assay, and both were shown, with and without metabolic activation, to be nonmutagenic to strains TA98 and TA100. The finding of other investigators that alternariol methyl ether is weakly mutagenic to Ta98 without metabolic activation could have resulted from the presence of a small amount of one of the highly mutagenic altertoxins in the alternariol methyl ether originally tested. 9 refs., 3 figs., 1 tab.

  11. An outbreak of Salmonella Typhimurium traced back to salami, Denmark, April to June 2010

    OpenAIRE

    Kuhn, K. G.; Torpdahl, M.; Frank, Christina; Sigsgaard, K.; Ethelberg, Steen

    2011-01-01

    Between April and June 2010, a small national outbreak of Salmonella Typhimurium with a particular multilocus variable-number tandem repeat analysis (MLVA) type was identified in Denmark through laboratory-based surveillance. The outbreak involved twenty cases, primarily living within the greater Copenhagen area. Half of the cases were children aged ten years or younger and 12 were male; three cases were hospitalised. A matched case-control study showed a strong link between illness and eatin...

  12. Microevolution during the emergence of a monophasic Salmonella Typhimurium epidemic in the United Kingdom

    OpenAIRE

    Petrovska, Liljana; Mather, Alison E.; AbuOun, Manal; Branchu, Priscilla; Harris, Simon R.; Connor, Thomas; K. L. Hopkins; Underwood, A.; Lettini, Antonia A.; Page, Andrew; Bagnall, Mary; Wain, John; Parkhill, Julian; Dougan, Gordon; Davies, Robert

    2016-01-01

    Microevolution associated with emergence and expansion of new epidemic clones of bacterial pathogens holds the key to epidemiologic success. To determine microevolution associated with monophasic Salmonella Typhimurium during an epidemic, we performed comparative whole-genome sequencing and phylogenomic analysis of isolates from the United Kingdom and Italy during 2005?2012. These isolates formed a single clade distinct from recent monophasic epidemic clones previously described from North Am...

  13. Epidemiological characteristics of Salmonella Typhimurium isolated from animals and feed in Poland

    DEFF Research Database (Denmark)

    Wasyl, D.; Sandvang, D.; Skov, M. N.

    2006-01-01

    Fifty-seven Salmonella Typhimurium strains isolated from poultry, swine and animal feed in Poland during the years 1979-1998 and 2000-2002 were analysed with conventional and molecular techniques. Antimicrobial resistance as well as multiresistance was found, respectively, in 80.1 % and 56......-mediated antimicrobial resistance in Poland. These findings are significant for public and animal health risks and document the dissemination of DT104 epidemic strains into new geographical regions....

  14. A Salmonella Typhimurium outbreak linked to Vietnamese bread rolls in South Western Sydney, Australia, 2015

    OpenAIRE

    Meena Chandra; Heidi Lord; Stephanie Fletcher-Lartey; Kate Alexander; Nilva Egana; Stephen Conaty

    2017-01-01

    Introduction: In September 2015, the South Western Sydney (SWS) Public Health Unit was notified of a cluster of Salmonella Typhimurium (STm) cases with a common multiple-locus variable-number tandem repeats analysis (MLVA) pattern. An investigation was conducted to identify a source and contain the outbreak. Methods: The cluster was initially identified through routine geographic information system cluster scanning applied to the New South Wales Notifiable Conditions Management System. Ad...

  15. An image classification approach to analyze the suppression of plant immunity by the human pathogen Salmonella Typhimurium.

    Science.gov (United States)

    Schikora, Marek; Neupane, Balram; Madhogaria, Satish; Koch, Wolfgang; Cremers, Daniel; Hirt, Heribert; Kogel, Karl-Heinz; Schikora, Adam

    2012-07-19

    The enteric pathogen Salmonella is the causative agent of the majority of food-borne bacterial poisonings. Resent research revealed that colonization of plants by Salmonella is an active infection process. Salmonella changes the metabolism and adjust the plant host by suppressing the defense mechanisms. In this report we developed an automatic algorithm to quantify the symptoms caused by Salmonella infection on Arabidopsis. The algorithm is designed to attribute image pixels into one of the two classes: healthy and unhealthy. The task is solved in three steps. First, we perform segmentation to divide the image into foreground and background. In the second step, a support vector machine (SVM) is applied to predict the class of each pixel belonging to the foreground. And finally, we do refinement by a neighborhood-check in order to omit all falsely classified pixels from the second step. The developed algorithm was tested on infection with the non-pathogenic E. coli and the plant pathogen Pseudomonas syringae and used to study the interaction between plants and Salmonella wild type and T3SS mutants. We proved that T3SS mutants of Salmonella are unable to suppress the plant defenses. Results obtained through the automatic analyses were further verified on biochemical and transcriptome levels. This report presents an automatic pixel-based classification method for detecting "unhealthy" regions in leaf images. The proposed method was compared to existing method and showed a higher accuracy. We used this algorithm to study the impact of the human pathogenic bacterium Salmonella Typhimurium on plants immune system. The comparison between wild type bacteria and T3SS mutants showed similarity in the infection process in animals and in plants. Plant epidemiology is only one possible application of the proposed algorithm, it can be easily extended to other detection tasks, which also rely on color information, or even extended to other features.

  16. An image classification approach to analyze the suppression of plant immunity by the human pathogen Salmonella Typhimurium

    Directory of Open Access Journals (Sweden)

    Schikora Marek

    2012-07-01

    Full Text Available Abstract Background The enteric pathogen Salmonella is the causative agent of the majority of food-borne bacterial poisonings. Resent research revealed that colonization of plants by Salmonella is an active infection process. Salmonella changes the metabolism and adjust the plant host by suppressing the defense mechanisms. In this report we developed an automatic algorithm to quantify the symptoms caused by Salmonella infection on Arabidopsis. Results The algorithm is designed to attribute image pixels into one of the two classes: healthy and unhealthy. The task is solved in three steps. First, we perform segmentation to divide the image into foreground and background. In the second step, a support vector machine (SVM is applied to predict the class of each pixel belonging to the foreground. And finally, we do refinement by a neighborhood-check in order to omit all falsely classified pixels from the second step. The developed algorithm was tested on infection with the non-pathogenic E. coli and the plant pathogen Pseudomonas syringae and used to study the interaction between plants and Salmonella wild type and T3SS mutants. We proved that T3SS mutants of Salmonella are unable to suppress the plant defenses. Results obtained through the automatic analyses were further verified on biochemical and transcriptome levels. Conclusion This report presents an automatic pixel-based classification method for detecting “unhealthy” regions in leaf images. The proposed method was compared to existing method and showed a higher accuracy. We used this algorithm to study the impact of the human pathogenic bacterium Salmonella Typhimurium on plants immune system. The comparison between wild type bacteria and T3SS mutants showed similarity in the infection process in animals and in plants. Plant epidemiology is only one possible application of the proposed algorithm, it can be easily extended to other detection tasks, which also rely on color information, or

  17. Proteins from latex of Calotropis procera prevent septic shock due to lethal infection by Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Lima-Filho, José V; Patriota, Joyce M; Silva, Ayrles F B; Filho, Nicodemos T; Oliveira, Raquel S B; Alencar, Nylane M N; Ramos, Márcio V

    2010-06-16

    The latex of Calotropis procera has been used in traditional medicine to treat different inflammatory diseases. The anti-inflammatory activity of latex proteins (LP) has been well documented using different inflammatory models. In this work the anti-inflammatory protein fraction was evaluated in a true inflammatory process by inducing a lethal experimental infection in the murine model caused by Salmonella enterica Subsp. enterica serovar Typhimurium. Experimental Swiss mice were given 0.2 ml of LP (30 or 60 mg/kg) by the intraperitoneal route 24 h before or after lethal challenge (0.2 ml) containing 10(6) CFU/ml of Salmonella Typhimurium using the same route of administration. All the control animals succumbed to infection within 6 days. When given before bacterial inoculums LP prevented the death of mice, which remained in observation until day 28. Even, LP-treated animals exhibited only discrete signs of infection which disappeared latter. LP fraction was also protective when given orally or by subcutaneous route. Histopathological examination revealed that necrosis and inflammatory infiltrates were similar in both the experimental and control groups on days 1 and 5 after infection. LP activity did not clear Salmonella Typhimurium, which was still present in the spleen at approximately 10(4) cells/g of organ 28 days after challenge. However, no bacteria were detected in the liver at this stage. LP did not inhibit bacterial growth in culture medium at all. In the early stages of infection bacteria population was similar in organs and in the peritoneal fluid but drastically reduced in blood. Titration of TNF-alpha in serum revealed no differences between experimental and control groups on days 1 and 5 days after infection while IL-12 was only discretely diminished in serum of experimental animals on day 5. Moreover, cultured macrophages treated with LP and stimulated by LPS released significantly less IL-1beta. LP-treated mice did not succumb to septic shock when

  18. Curcumin increases the pathogenicity of Salmonella enterica serovar Typhimurium in murine model.

    Directory of Open Access Journals (Sweden)

    Sandhya A Marathe

    Full Text Available Curcumin has gained immense importance for its vast therapeutic and prophylactic applications. Contrary to this, our study reveals that it regulates the defense pathways of Salmonella enterica serovar Typhimurium (S. Typhimurium to enhance its pathogenicity. In a murine model of typhoid fever, we observed higher bacterial load in Peyer's patches, mesenteric lymph node, spleen and liver, when infected with curcumin-treated Salmonella. Curcumin increased the resistance of S. Typhimurium against antimicrobial agents like antimicrobial peptides, reactive oxygen and nitrogen species. This increased tolerance might be attributed to the up-regulation of genes involved in resistance against antimicrobial peptides--pmrD and pmrHFIJKLM and genes with antioxidant function--mntH, sodA and sitA. We implicate that iron chelation property of curcumin have a role in regulating mntH and sitA. Interestingly, we see that the curcumin-mediated modulation of pmr genes is through the PhoPQ regulatory system. Curcumin downregulates SPI1 genes, required for entry into epithelial cells and upregulates SPI2 genes required to intracellular survival. Since it is known that the SPI1 and SPI2 system can be regulated by the PhoPQ system, this common regulator could explain curcumin's mode of action. This data urges us to rethink the indiscriminate use of curcumin especially during Salmonella outbreaks.

  19. Three New Lactobacillus plantarum Strains in the Probiotic Toolbox against Gut Pathogen Salmonella enterica Serotype Typhimurium

    Directory of Open Access Journals (Sweden)

    Mia Potočnjak

    2017-01-01

    Full Text Available The benefits of probiotic bacteria have been widely explored. However, fermented foods and digestive system of humans and animals are an inexhaustible source of new potentially probiotic microorganisms. In this study we present three new Lactobacillus plantarum strains isolated from different dairy products: cow′s cheese, sheep′s cheese and whey. In order to determine the antibacterial activity of yet unexplored L. plantarum strains against Salmonella enterica serotype Typhimurium, in vitro competition and co-culture tests were done. Furthermore, adhesion of these strains to Caco-2 cells and their influence on the adhesion of Salmonella were tested. Results showed the potential probiotic activity of isolated strains. L. plantarum strains survived in the presence of 1 % bile salts, they possessed acidification ability, antibacterial activity and significantly attenuated the growth of S. Typhimurium in brain heart infusion broth. All tested L. plantarum strains were able to adhere to Caco-2 cells and significantly impair the adhesion of S. Typhimurium. All three L. plantarum strains exhibited signifi cant probiotic potential and anti-Salmonella activity; therefore, further testing on in vivo models should follow.

  20. Characterization and differential gene expression between two phenotypic phase variants in Salmonella enterica serovar Typhimurium.

    Directory of Open Access Journals (Sweden)

    Sheila K Patterson

    Full Text Available Salmonella enterica serovar Typhimurium strain 798 has previously been shown to undergo phenotypic phase variation. One of the phenotypes expresses virulence traits such as adhesion, while the other phenotype does not. Phenotypic phase variation appears to correlate with the ability of this strain to cause persistent, asymptomatic infections of swine. A new method to detect cells in either phenotypic phase was developed using Evans Blue-Uranine agar plates. Using this new assay, rates of phenotypic phase variation were obtained. The rate of phase variation from non-adhesive to adhesive phenotype was approximately 10(-4 per cell per generation while phase variation from the adhesive to the non-adhesive phenotype was approximately 10(-6 per cell per generation. Two highly virulent S. Typhimurium strains, SL1344 and ATCC 14028, were also shown to undergo phase variation. However, while the rate from adhesive to non-adhesive phenotype was approximately the same as for strain 798, the non-adhesive to adhesive phenotype shift was 37-fold higher. Differential gene expression was measured using RNA-Seq. Eighty-three genes were more highly expressed by 798 cells in the adhesive phenotype compared to the non-adhesive cells. Most of the up-regulated genes were in virulence genes and in particular all genes in the Salmonella pathogenicity island 1 were up-regulated. When compared to the virulent strain SL1344, expression of the virulence genes was approximately equal to those up-regulated in the adhesive phenotype of strain 798. A comparison of invasive ability demonstrated that strain SL1344 was the most invasive followed by the adhesive phenotype of strain 798, then the non-adhesive phenotype of strain 798. The least invasive strain was ATCC 14028. The genome of strain 798 was sequenced and compared to SL1344. Both strains had very similar genome sequences and gene deletions could not readily explain differences in the rates of phase variation from non

  1. Multiple roles of putrescine and spermidine in stress resistance and virulence of Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Espinel, Irene Cartas; Guerra, Priscila Regina; Jelsbak, Lotte

    2016-06-01

    Polyamines (putrescine and spermidine) are small-cationic amines ubiquitous in nature and present in most living cells. In recent years they have been linked to virulence of several human pathogens including Shigella spp and Salmonella enterica serovar Typhimurium (S. Typhimurium). Central to S. Typhimurium virulence is the ability to survive and replicate inside macrophages and resisting the antimicrobial attacks in the form of oxidative and nitrosative stress elicited from these cells. In the present study, we have investigated the role of polyamines in intracellular survival and systemic infections of mice. Using a S. Typhimurium mutant defective for putrescine and spermidine biosynthesis, we show that polyamines are essential for coping with reactive nitrogen species, possibly linking polyamines to increased intracellular stress resistance. However, using a mouse model defective for nitric oxide production, we find that polyamines are required for systemic infections independently of host-produced reactive nitrogen species. To distinguish between the physiological roles of putrescine and spermidine, we constructed a strain deficient for spermidine biosynthesis and uptake, but with retained ability to produce and import putrescine. Interestingly, in this mutant we observe a strong attenuation of virulence during infection of mice proficient and deficient for nitric oxide production suggesting that spermidine, specifically, is essential for virulence of S. Typhimurium. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. A new wireless detection device for the in-situ identification of Salmonella Typhimurium

    Science.gov (United States)

    Chai, Yating; Wikle, Howard C.; Park, Mi-kyung; Horikawa, Shin; Hong, Xie; Chin, Bryan A.

    2013-05-01

    This paper presents a new device and method for the in-situ detection of Salmonella Typhimurium on tomato surfaces. This real-time in-situ detection was accomplished with phage-based magnetoelastic (ME) biosensors on fresh food surfaces. The E2 phage from a landscape phage library serves as the bio-recognition element that has the capability of binding specifically with S. Typhimurium. This mass-sensitive ME biosensor is wirelessly actuated into mechanical resonance by an externally applied time-varying magnetic field. When the biosensor binds with S. Typhimurium, the mass of the sensor increases, resulting in a decrease in the sensor's resonant frequency. Until now, ME sensors had to be collected from the tomato surface where they are exposed to S. Typhimurium and inserted into a measurement coil for the detection of the bacterium. In contrast, the newly designed test device allows the whole detection process to take place directly on the tomato. Changes in resonant frequency over time due to the accumulation of S. Typhimurium on the sensor were measured and are presented. Real-time in-situ detection of 20 minutes was achieved. In addition, this new methodology effectively decreases the measurement error and enables the simultaneous detection of multiple pathogens.

  3. Salmonella typhimurium and Escherichia coli dissimilarity: Closely related bacteria with distinct metabolic profiles.

    Science.gov (United States)

    Sargo, Cintia R; Campani, Gilson; Silva, Gabriel G; Giordano, Roberto C; Da Silva, Adilson J; Zangirolami, Teresa C; Correia, Daniela M; Ferreira, Eugénio C; Rocha, Isabel

    2015-01-01

    Live attenuated strains of Salmonella typhimurium have been extensively investigated as vaccines for a number of infectious diseases. However, there is still little information available concerning aspects of their metabolism. S. typhimurium and Escherichia coli show a high degree of similarity in terms of their genome contents and metabolic networks. However, this work presents experimental evidence showing that significant differences exist in their abilities to direct carbon fluxes to biomass and energy production. It is important to study the metabolism of Salmonella to elucidate the formation of acetate and other metabolites involved in optimizing the production of biomass, essential for the development of recombinant vaccines. The metabolism of Salmonella under aerobic conditions was assessed using continuous cultures performed at dilution rates ranging from 0.1 to 0.67 h(-1), with glucose as main substrate. Acetate assimilation and glucose metabolism under anaerobic conditions were also investigated using batch cultures. Chemostat cultivations showed deviation of carbon towards acetate formation, starting at dilution rates above 0.1 h(-1). This differed from previous findings for E. coli, where acetate accumulation was only detected at dilution rates exceeding 0.4 h(-1), and was due to the lower rate of acetate assimilation by S. typhimurium under aerobic conditions. Under anaerobic conditions, both microorganisms mainly produced ethanol, acetate, and formate. A genome-scale metabolic model, reconstructed for Salmonella based on an E. coli model, provided a poor description of the mixed fermentation pattern observed during Salmonella cultures, reinforcing the different patterns of carbon utilization exhibited by these closely related bacteria. © 2015 American Institute of Chemical Engineers.

  4. Modelling transfer of Salmonella Typhimurium DT104 during simulation of grinding of pork.

    Science.gov (United States)

    Møller, C O A; Nauta, M J; Christensen, B B; Dalgaard, P; Hansen, T B

    2012-01-01

    The aim of this study was to develop a model to predict cross-contamination of Salmonella during grinding of pork. Transfer rates of Salmonella were measured in three experiments, where between 10 and 20 kg meat was ground into 200-g portions. In each experiment, five pork slices of about 200 g per slice were inoculated with 8-9 log-units of Salmonella Typhimurium DT104 and used for building up the contamination in the grinder. Subsequently, Salmonella-free slices were ground and collected as samples of c. 200 g minced pork. Throughout the process, representative samples were quantitatively analysed for Salmonella. A model suggested by Nauta et al. (2005) predicting cross-contamination of Campylobacter in poultry processing and two modified versions of this model were tested. The present study observed a tailing phenomenon of transfer of Salmonella during a small-scale grinding process. It was, therefore, hypothesized that transfer occurred from two environmental matrices inside the grinder and a model was developed. The developed model satisfactorily predicted the observed concentrations of Salmonella during its cross-contamination in the grinding of up to 110 pork slices. The proposed model provides an important tool to examine the effect of cross-contamination in quantitative microbial risk assessments and might also be applied to various other food processes where cross-contamination is involved. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  5. Dietary rice bran promotes resistance to Salmonella enterica serovar Typhimurium colonization in mice

    Directory of Open Access Journals (Sweden)

    Kumar Ajay

    2012-07-01

    Full Text Available Abstract Background Dietary rice bran consists of many bioactive components with disease fighting properties; including the capacity to modulate the gut microbiota. Studies point to the important roles of the gut microbiota and the mucosal epithelium in the establishment of protection against enteric pathogens, such as Salmonella. The ability of rice bran to reduce the susceptibility of mice to a Salmonella infection has not been previously investigated. Therefore, we hypothesized that the incorporation of rice bran into the diet would inhibit the colonization of Salmonella in mice through the induction of protective mucosal responses. Results Mice were fed diets containing 0%, 10% and 20% rice bran for one week prior to being orally infected with Salmonella enterica serovar Typhimurium. We found that mice consuming the 10 and 20% rice bran diets exhibited a reduction in Salmonella fecal shedding for up to nine days post-infection as compared to control diet fed animals (p Lactobacillus spp. in rice bran fed mice (p Salmonella entry into mouse small intestinal epithelial cells. Conclusions Increasing rice bran consumption represents a novel dietary means for reducing susceptibility to enteric infection with Salmonella and potentially via induction of native Lactobacillus spp.

  6. Mortality and translocation assay to study the protective capacity of Bifidobacterium lactis INL1 against Salmonella Typhimurium infection in mice.

    Science.gov (United States)

    Zacarías, M F; Reinheimer, J; Forzani, L; Grangette, C; Vinderola, G

    2014-12-01

    The mouse has been largely used for the study of the protective capacity of probiotics against intestinal infections caused by Salmonella. In this work we aimed at comparing the mortality and translocation assay for the study of the protective capacity of the human breast milk-derived strain Bifidobacterium animalis subsp. lactis INL1 on a model of gut infection by Salmonella enterica subsp. enterica serovar Typhimurium. Different doses of S. Typhimurium FUNED and B. animalis subsp. lactis INL 1 were administered to Balb/c mice in a mortality or a translocation assay. The survival of the control group in the mortality assay resulted to be variable along experiments, and then we preferred to use a translocation assay where the preventive administration of 109 cfu of bifidobacteria/mouse for 10 consecutive days significantly reduced the number of infected animals and the levels of translocation to liver and spleen, with enhanced secretory immunoglobulin A and interleukin 10 production in the small and large intestine, respectively. Ten days of B. animalis subsp. lactis strain INL1 administration to mice significantly reduced both the incidence and the severity of Salmonella infection in a mouse model of translocation. This work provided the first evidence that a translocation assay, compared to a mortality assay, could be more useful to study the protective capacity of probiotics against Salmonella infection, as more information can be obtained from mice and less suffering is conferred to animals due to the fact that the mortality assay is shorter than the latter. These facts are in line with the guidelines of animal research recently established by the National Centre for the Replacement, Refinement & Reduction of Animals in Research.

  7. Salmonella Typhimurium strain ATCC14028 requires H2-hydrogenases for growth in the gut, but not at systemic sites.

    Directory of Open Access Journals (Sweden)

    Lisa Maier

    Full Text Available Salmonella enterica is a common cause of diarrhea. For eliciting disease, the pathogen has to colonize the gut lumen, a site colonized by the microbiota. This process/initial stage is incompletely understood. Recent work established that one particular strain, Salmonella enterica subspecies 1 serovar Typhimurium strain SL1344, employs the hyb H2-hydrogenase for consuming microbiota-derived H2 to support gut luminal pathogen growth: Protons from the H2-splitting reaction contribute to the proton gradient across the outer bacterial membrane which can be harvested for ATP production or for import of carbon sources. However, it remained unclear, if other Salmonella strains would use the same strategy. In particular, earlier work had left unanswered if strain ATCC14028 might use H2 for growth at systemic sites. To clarify the role of the hydrogenases, it seems important to establish if H2 is used at systemic sites or in the gut and if Salmonella strains may differ with respect to the host sites where they require H2 in vivo. In order to resolve this, we constructed a strain lacking all three H2-hydrogenases of ATCC14028 (14028hyd3 and performed competitive infection experiments. Upon intragastric inoculation, 14028hyd3 was present at 100-fold lower numbers than 14028WT in the stool and at systemic sites. In contrast, i.v. inoculation led to equivalent systemic loads of 14028hyd3 and the wild type strain. However, the pathogen population spreading to the gut lumen featured again up to 100-fold attenuation of 14028hyd3. Therefore, ATCC14028 requires H2-hydrogenases for growth in the gut lumen and not at systemic sites. This extends previous work on ATCC14028 and supports the notion that H2-utilization might be a general feature of S. Typhimurium gut colonization.

  8. Some putative prebiotics increase the severity of Salmonella enterica serovar Typhimurium infection in mice

    Directory of Open Access Journals (Sweden)

    Lahtinen Sampo

    2009-01-01

    Full Text Available Abstract Background Prebiotics are non-digestible food ingredients believed to beneficially affect host health by selectively stimulating the growth of the beneficial bacteria residing in the gut. Such beneficial bacteria have been reported to protect against pathogenic infections. However, contradicting results on prevention of Salmonella infections with prebiotics have been published. The aim of the present study was to examine whether S. Typhimurium SL1344 infection in mice could be prevented by administration of dietary carbohydrates with different structures and digestibility profiles. BALB/c mice were fed a diet containing 10% of either of the following carbohydrates: inulin, fructo-oligosaccharide, xylo-oligosaccharide, galacto-oligosaccharide, apple pectin, polydextrose or beta-glucan for three weeks prior to oral Salmonella challenge (107 CFU and compared to mice fed a cornstarch-based control diet. Results The mice fed with diets containing fructo-oligosaccharide (FOS or xylo-oligosaccharide (XOS had significantly higher (P < 0.01 and P < 0.05 numbers of S. Typhimurium SL1344 in liver, spleen and mesenteric lymph nodes when compared to the mice fed with the cornstarch-based control diet. Significantly increased amounts (P < 0.01 of Salmonella were detected in ileal and fecal contents of mice fed with diets supplemented with apple pectin, however these mice did not show significantly higher numbers of S. Typhimyrium in liver, spleen and lymph nodes than animals from the control group (P < 0.20. The acute-phase protein haptoglobin was a good marker for translocation of S. Typhimurium in mice. In accordance with the increased counts of Salmonella in the organs, serum concentrations of haptoglobin were significantly increased in the mice fed with FOS or XOS (P < 0.001. Caecum weight was increased in the mice fed with FOS (P < 0.01, XOS (P < 0.01, or polydextrose (P < 0.001, and caecal pH was reduced in the mice fed with polydextrose (P < 0

  9. In vitro and in vivo virulence of Salmonella Typhimurium DT104: a parallelogram approach

    NARCIS (Netherlands)

    Berk, P.A.

    2008-01-01

    Salmonella is present in different food products. In this research it is concluded that Salmonella, which can survive the stomach of humans better (acid resistant bacteria), have a higher probability of causing an infection than Salmonella strains that are less able to survive the stomach (acid

  10. Polyamines Are Required for Virulence in Salmonella enterica Serovar Typhimurium

    DEFF Research Database (Denmark)

    Jelsbak, Lotte; Thomsen, Line Elnif; Wallrodt, Inke

    2012-01-01

    and intracellular survival could, as well, be complemented by the addition of exogenous putrescine and spermidine to the bacterial cultures prior to infection. Interestingly, intracellular survival of the polyamine mutant was significantly enhanced above the wild type level by the addition of exogenous putrescine...... from both of the major virulence loci SPI1 and SPI2 responded to exogenous polyamines and was reduced in the polyamine mutant. Together our data demonstrate that putrescine and spermidine play a critical role in controlling virulence in S. Typhimurium most likely through stimulation of expression...

  11. Novel inducers of the envelope stress response BaeSR in Salmonella Typhimurium: BaeR is critically required for tungstate waste disposal.

    Directory of Open Access Journals (Sweden)

    Corinne Appia-Ayme

    Full Text Available The RpoE and CpxR regulated envelope stress responses are extremely important for Salmonella Typhimurium to cause infection in a range of hosts. Until now the role for BaeSR in both the Salmonella Typhimurium response to stress and its contribution to infection have not been fully elucidated. Here we demonstrate stationary phase growth, iron and sodium tungstate as novel inducers of the BaeRregulon, with BaeR critically required for Salmonella resistance to sodium tungstate. We show that functional overlap between the resistance nodulation-cell division (RND multidrug transporters, MdtA, AcrD and AcrB exists for the waste disposal of tungstate from the cell. We also point to a role for enterobactinsiderophores in the protection of enteric organisms from tungstate, akin to the scenario in nitrogen fixing bacteria. Surprisingly, BaeR is the first envelope stress response pathway investigated in S. Typhimurium that is not required for murine typhoid in either ity(S or ity(R mouse backgrounds. BaeR is therefore either required for survival in larger mammals such as pigs or calves, an avian host such as chickens, or survival out with the host altogether where Salmonella and related enterics must survive in soil and water.

  12. O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections

    OpenAIRE

    Li, Pei; Liu, Qing; Luo, Hongyan; Liang, Kang; Yi, Jie; Luo, Ying; Hu, Yunlong; Han, Yue; Kong, Qingke

    2017-01-01

    Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C...

  13. Immuno-capture and in situ detection of Salmonella typhimurium on a novel microfluidic chip

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Renjie, E-mail: 1058464972@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Ni, Yanan, E-mail: 468885029@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Xu, Yi, E-mail: xuyibbd@sina.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); National Center for International Research of Micro/Nano-System and New Material Technology, No. 174, St. Shazhengjie, Shapingba District, Chongqing (China); Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology for National Defense, Chongqing (China); Jiang, Yan, E-mail: 919865356@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Dong, Chunyan, E-mail: 774176325@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Chuan, Na, E-mail: 814859441@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China)

    2015-01-01

    Highlights: • A novel microfluidic chip and a LIF microsystem were designed and fabricated. • Salmonella typhimurium was captured and labeled by specific immuno-capture on chip. • CdSe/ZnS quantum dots-labeled bacteria were detected by in situ analysis using LIF microsystem. • The proposed method has potential application in practice. - Abstract: The new method presented in this article achieved the goal of capturing Salmonella typhimurium via immunoreaction and rapid in situ detection of the CdSe/ZnS quantum dots (QDs) labeled S. typhimurium by self-assembly light-emitting diode-induced fluorescence detection (LIF) microsystem on a specially designed multichannel microfluidic chip. CdSe/ZnS QDs were used as fluorescent markers improving detection sensitivity. The microfluidic chip developed in this study was composed of 12 sample channels, 3 mixing zones, and 6 immune reaction zones, which also acted as fluorescence detection zones. QDs–IgG–primary antibody complexes were generated by mixing CdSe/ZnS QDs conjugated secondary antibody (QDs–IgG) and S. typhimurium antibody (primary antibody) in mixing zones. Then, the complexes went into immune reaction zones to label previously captured S. typhimurium in the sandwich mode. The capture rate of S. typhimurium in each detection zone was up to 70%. The enriched QDs-labeled S. typhimurium was detected using a self-assembly LIF microsystem. A good linear relationship was obtained in the range from 3.7 × 10 to 3.7 × 10{sup 5} cfu mL{sup −1} using the equation I = 0.1739 log (C) − 0.1889 with R{sup 2} = 0.9907, and the detection limit was down to 37 cfu mL{sup −1}. The proposed method of online immunolabeling with QDs for in situ fluorescence detection on the designed multichannel microfluidic chip had been successfully used to detect S. typhimurium in pork sample, and it has shown potential advantages in practice.

  14. Analysis of the ArcA regulon in anaerobically grown Salmonella enterica sv. Typhimurium

    Directory of Open Access Journals (Sweden)

    Porwollik Steffen

    2011-03-01

    Full Text Available Abstract Background Salmonella enterica serovar Typhimurium (S. Typhimurium is a Gram-negative pathogen that must successfully adapt to the broad fluctuations in the concentration of dissolved dioxygen encountered in the host. In Escherichia coli, ArcA (Aerobic Respiratory Control helps the cells to sense and respond to the presence of dioxygen. The global role of ArcA in E. coli is well characterized; however, little is known about its role in anaerobically grown S. Typhimurium. Results We compared the transcriptional profiles of the virulent wild-type (WT strain (ATCC 14028s and its isogenic arcA mutant grown under anaerobic conditions. We found that ArcA directly or indirectly regulates 392 genes (8.5% of the genome; of these, 138 genes are poorly characterized. Regulation by ArcA in S. Typhimurium is similar, but distinct from that in E. coli. Thus, genes/operons involved in core metabolic pathways (e.g., succinyl-CoA, fatty acid degradation, cytochrome oxidase complexes, flagellar biosynthesis, motility, and chemotaxis were regulated similarly in the two organisms. However, genes/operons present in both organisms, but regulated differently by ArcA in S. Typhimurium included those coding for ethanolamine utilization, lactate transport and metabolism, and succinate dehydrogenases. Salmonella-specific genes/operons regulated by ArcA included those required for propanediol utilization, flagellar genes (mcpAC, cheV, Gifsy-1 prophage genes, and three SPI-3 genes (mgtBC, slsA, STM3784. In agreement with our microarray data, the arcA mutant was non-motile, lacked flagella, and was as virulent in mice as the WT. Additionally, we identified a set of 120 genes whose regulation was shared with the anaerobic redox regulator, Fnr. Conclusion(s We have identified the ArcA regulon in anaerobically grown S. Typhimurium. Our results demonstrated that in S. Typhimurium, ArcA serves as a transcriptional regulator coordinating cellular metabolism, flagella

  15. Attachment behaviour of Escherichia coli K12 and Salmonella Typhimurium P6 on food contact surfaces for food transportation.

    Science.gov (United States)

    Abban, Stephen; Jakobsen, Mogens; Jespersen, Lene

    2012-09-01

    The role of cargo container lining materials aluminium, a fibre reinforced plastic (FRP) and stainless steel in bacterial cross contamination during transport was assessed. For this, attachment and detachment of Escherichia coli K12 and Salmonella Typhimurium P6 on the three surfaces in the absence or presence of residues were evaluated. Observations were correlated with water contact angles of the materials (hydrophobicity) and roughness profile (R(a)). Attachment of the organisms was negatively correlated to the hydrophobicity of the three materials with r = -0.869 and -0.861 for E. coli K12 and S. Typhimurium P6 respectively. Correlation with roughness average was poor; r = -0.425 and -0.413 respectively for E. coli K12 and S. Typhimurium P6. Presence of residue caused significant reduction (p food residue and soils affect the extent and amount of bacteria attaching to abiotic surfaces by altering the surface contact properties for the bacteria. Physicochemical properties like hydrophobicity appear to be a better basis for material selection for hygienic design of containers, than the traditional use of R(a). Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Detection of Salmonella Typhimurium on Spinach Using Phage-Based Magnetoelastic Biosensors

    Directory of Open Access Journals (Sweden)

    Fengen Wang

    2017-02-01

    Full Text Available Phage-based magnetoelastic (ME biosensors have been studied as an in-situ, real-time, wireless, direct detection method of foodborne pathogens in recent years. This paper investigates an ME biosensor method for the detection of Salmonella Typhimurium on fresh spinach leaves. A procedure to obtain a concentrated suspension of Salmonella from contaminated spinach leaves is described that is based on methods outlined in the U.S. FDA Bacteriological Analytical Manual for the detection of Salmonella on leafy green vegetables. The effects of an alternative pre-enrichment broth (LB broth vs. lactose broth, incubation time on the detection performance and negative control were investigated. In addition, different blocking agents (BSA, Casein, and Superblock were evaluated to minimize the effect of nonspecific binding. None of the blocking agents was found to be superior to the others, or even better than none. Unblocked ME biosensors were placed directly in a concentrated suspension and allowed to bind with Salmonella cells for 30 min before measuring the resonant frequency using a surface-scanning coil detector. It was found that 7 h incubation at 37 °C in LB broth was necessary to detect an initial spike of 100 cfu/25 g S. Typhimurium on spinach leaves with a confidence level of difference greater than 95% (p < 0.05. Thus, the ME biosensor method, on both partly and fully detection, was demonstrated to be a robust and competitive method for foodborne pathogens on fresh products.

  17. Pathologic and microbiologic aspects of pet psittacine infected by Escherichia coli and Salmonella Typhimurium

    Directory of Open Access Journals (Sweden)

    Raul A.S. Siqueira

    Full Text Available ABSTRACT: The role of Escherichia coli in healthy microbiota of psittacine is controversial, and the presence of Salmonella sp. indicates possible disease. Therefore, this study aimed to identify the presence of E. coli and Salmonella spp. in a psittacine pet that died in Fortaleza, Brazil, correlating pathogenicity aspects of the isolates through the evaluation of lesions and antimicrobial susceptibility. Psittacine pets sent to the Laboratory of Ornithological Studies, State University of Ceará, that died in 2014 and 2015 were necropsied. Fragments of liver, kidneys, intestine, lung, heart, spleen and brain were collected for microbiological and histopathological analyses. Scores were attributed to lesions and isolated strains submitted to antimicrobial susceptibility test. From the seventy necropsied birds, nineteen were positive for E. coli and one for Salmonella Typhimurium. Congestive lesions and lymphoplasmocitic inflammatory infiltrate were observed varying from light to moderate and were the main findings. In the analyzed strains, multidrug resistance against different groups of antibiotics was observed. In conclusion, according to the results, E. coli strains and the Salmonella Typhimurium isolate produced significant lesions in the psittacine pets, and multidrug resistance may hinder treatments with antibiotics used in avian pet medicine.

  18. Rapid DNA transformation in Salmonella Typhimurium by the hydrogel exposure method.

    Science.gov (United States)

    Elabed, Hamouda; Hamza, Rim; Bakhrouf, Amina; Gaddour, Kamel

    2016-07-01

    Even with advances in molecular cloning and DNA transformation, new or alternative methods that permit DNA penetration in Salmonella enterica subspecies enterica serovar Typhimurium are required in order to use this pathogen in biotechnological or medical applications. In this work, an adapted protocol of bacterial transformation with plasmid DNA based on the "Yoshida effect" was applied and optimized on Salmonella enterica serovar Typhimurium LT2 reference strain. The plasmid transference based on the use of sepiolite as acicular materials to promote cell piercing via friction forces produced by spreading on the surface of a hydrogel. The transforming mixture containing sepiolite nanofibers, bacterial cells to be transformed and plasmid DNA were plated directly on selective medium containing 2% agar. In order to improve the procedure, three variables were tested and the transformation of Salmonella cells was accomplished using plasmids pUC19 and pBR322. Using the optimized protocol on Salmonella LT2 strain, the efficiency was about 10(5) transformed cells per 10(9) subjected to transformation with 0.2μg plasmid DNA. In summary, the procedure is fast, offers opportune efficiency and promises to become one of the widely used transformation methods in laboratories. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Lactobacillus bulgaricus, Lactobacillus rhamnosus and Lactobacillus paracasei Attenuate Salmonella Enteritidis, Salmonella Heidelberg and Salmonella Typhimurium Colonization and Virulence Gene Expression In Vitro

    Directory of Open Access Journals (Sweden)

    Muhammed Shafeekh Muyyarikkandy

    2017-11-01

    Full Text Available Salmonella Enteritidis (SE, Salmonella Typhimurium (ST, and Salmonella Heidelberg (SH have been responsible for numerous outbreaks associated with the consumption of poultry meat and eggs. Salmonella colonization in chicken is characterized by initial attachment to the cecal epithelial cells (CEC followed by dissemination to the liver, spleen, and oviduct. Since cecal colonization is critical to Salmonella transmission along the food chain continuum, reducing this intestinal association could potentially decrease poultry meat and egg contamination. Hence, this study investigated the efficacy of Lactobacillus delbreuckii sub species bulgaricus (NRRL B548; LD, Lactobacillus paracasei (DUP-13076; LP, and Lactobacillus rhamnosus (NRRL B442; LR in reducing SE, ST, and SH colonization in CEC and survival in chicken macrophages. Additionally, their effect on expression of Salmonella virulence genes essential for cecal colonization and survival in macrophages was evaluated. All three probiotics significantly reduced Salmonella adhesion and invasion in CEC and survival in chicken macrophages (p < 0.05. Further, the probiotic treatment led to a significant reduction in Salmonella virulence gene expression (p < 0.05. Results of the study indicate that LD, LP, and LR could potentially be used to control SE, ST, and SH colonization in chicken. However, these observations warrant further in vivo validation.

  20. Natural surface coating to inactivate Salmonella enterica serovar Typhimurium and maintain quality of cherry tomatoes.

    Science.gov (United States)

    Yun, Juan; Fan, Xuetong; Li, Xihong; Jin, Tony Z; Jia, Xiaoyu; Mattheis, James P

    2015-01-16

    The objective of the present study was to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three attenuated strains on the smooth skin surface and stem scar area. The zein-based coatings with and without cinnamon (up to 20%) and mustard essential oil or a commercial wax formulation were applied onto tomatoes and the treated fruits were stored at 10 °C for up to 3 weeks. Populations of S. Typhimurium decreased with increased essential oil concentration and storage duration. S. Typhimurium populations on the smooth skin surface were reduced by 4.6 and 2.8 log colony forming units(CFU)/g by the zein coatings with 20% cinnamon and 20% mustard oil, respectively, 5h after coating. The same coating reduced populations of S. Typhimurium to levels below detection limit (1.0 log CFU/g) on the stem scar area of tomato during 7 days of storage at 10 °C. Salmonella populations were not reduced on fruit coated with the commercial wax. All of the coatings resulted in reduced weight loss compared with uncoated control. Compared with the control, loss of firmness and ascorbic acid during storage was prevented by all of the coatings except the zein coating with 20% mustard oil which enhanced softening. Color was not consistently affected by any of the coating treatments during 21 days of storage at 10°C. The results suggest that the zein-based coating containing cinnamon oil might be used to enhance microbial safety and quality of tomato. Published by Elsevier B.V.

  1. Inhibition and inactivation of Salmonella typhimurium biofilms from polystyrene and stainless steel surfaces by essential oils and phenolic constituent carvacrol.

    Science.gov (United States)

    Soni, Kamlesh A; Oladunjoye, Ademola; Nannapaneni, Ramakrishna; Schilling, M Wes; Silva, Juan L; Mikel, Benjy; Bailey, R Hartford

    2013-02-01

    Persistence of Salmonella biofilms within food processing environments is an important source of Salmonella contamination in the food chain. In this study, essential oils of thyme and oregano and their antimicrobial phenolic constituent carvacrol were evaluated for their ability to inhibit biofilm formation and inactivate preformed Salmonella biofilms. A crystal violet staining assay and CFU measurements were utilized to quantify biofilm cell mass, with evaluating factors such as strain variation, essential oil type, their concentrations, exposure time, as well as biofilm formation surface. Of the three Salmonella strains, Salmonella Typhimurium ATCC 23564 and Salmonella Typhimurium ATCC 19585 produced stronger biofilms than Salmonella Typhimurium ATCC 14028. Biofilm formation by different Salmonella strains was 1.5- to 2-fold higher at 22°C than at 30 or 37°C. The presence of nonbiocidal concentrations of thyme oil, oregano oil, and phenolic carvacrol at 0.006 to 0.012% suppressed Salmonella spp. biofilm formation 2- to 4-fold, but could not completely eliminate biofilm formation. There was high correlation in terms of biofilm inactivation, as determined by the crystal violet-stained optical density (at a 562-nm wavelength) readings and the viable CFU counts. Reduction of biofilm cell mass was dependent on antimicrobial concentration. A minimum concentration of 0.05 to 0.1% of these antimicrobial agents was needed to reduce a 7-log CFU biofilm mass to a nondetectable level on both polystyrene and stainless steel surfaces within 1 h of exposure time.

  2. Radiation survival of two nalidixic acid resistant strains of Salmonella typhimurium in various media

    Science.gov (United States)

    Shamsuzzaman, Kazi; Goodwin, Marlene; George, Ian; Singh, Harwant

    Radiation doses required for 90% inactivation, the D10 values, have been determined for two nalidixic acid-resistant strains of Salmonella typhimurium, Nal R ATCC 13311 and K1-2B, in different media. The D10 values were 0.20, 0.57 and 0.53 kGy for the ATCC 13311 strain, and were 0.21, 0.4 and 0.32 kGy for the K1-2B strain, in phosphate buffer, in nutrient broth and on chicken drumsticks, respectively. Since these two strains have radiation sensitivity similar to several Salmonella serotypes reported in the literature, they are good indicator organisms for use in studies on the effect of irradiation on Salmonella in foods that might frequently be contaminated with such organisms.

  3. Growth potential of exponential- and stationary-phase Salmonella Typhimurium during sausage fermentation

    DEFF Research Database (Denmark)

    Birk, Tina; Henriksen, Sidsel; Müller, K.

    2016-01-01

    Raw meat for sausage production can be contaminated with Salmonella. For technical reasons, meat is often frozen prior to mincing but it is unknown how growth of Salmonella in meat prior to freezing affects its growth potential during sausage fermentation. We investigated survival of exponential......- and stationary-phase Salmonella Typhimurium (DT12 and DTU292) during freezing at − 18 °C and their subsequent growth potential during 72 h sausage fermentation at 25 °C. After 0, 7 and > 35 d of frozen storage, sausage batters were prepared with NaCl (3%) and NaNO2 (0, 100 ppm) and fermented with and without...

  4. An outbreak of Salmonella Typhimurium DT191a associated with reptile feeder mice.

    Science.gov (United States)

    Harker, K S; Lane, C; De Pinna, E; Adak, G K

    2011-08-01

    In December 2008 an increase of tetracycline-resistant Salmonella Typhimurium definitive phage-type 191a (DT191a) was identified in England and Wales by the reference laboratory. This was confirmed to have a phage-typing pattern that had not previously been seen. Strong statistical evidence for an association between illness and keeping reptiles was demonstrated by a matched case-case study (mOR 16·82, 95% CI 2·78-∞). Questionnaires revealed an association with frozen reptile feeder mice, and mice representing 80% of the UK supply lines were tested for the presence of Salmonella. DT191a was found in three pools of sampled mice, which were traced back to a single supplier in the USA. Imports from this supplier were halted, and tighter regulations are now in place. A leaflet detailing how to prevent contracting Salmonella from pet reptiles has been published as well as updated advice on the Health Protection Agency's website.

  5. Disruption of type III secretion in Salmonella enterica serovar Typhimurium by external guide sequences.

    Science.gov (United States)

    McKinney, Jeffrey S; Zhang, Haifeng; Kubori, Tomoko; Galán, Jorge E; Altman, Sidney

    2004-01-01

    The type III secretion system involved in Salmonella enterica serovar Typhimurium invasion of host cells has been disrupted using inducibly expressed oligonucleotide external guide sequences (EGSs) complementary to invB or invC mRNA. These EGSs direct single site cleavage in these mRNAs by endogenous RNase P, and their expression in Salmonella results in invC mRNA and InvC protein depletion, decreased type III secretion and interference with host cell invasion. Comparison of these effects with those from studies of Salmonella invB and invC mutants suggests that invB EGSs have polar effects on invC mRNA.

  6. Modelling transfer of Salmonella Typhimurium DT104 during simulation of grinding of pork

    DEFF Research Database (Denmark)

    Møller, Cleide; Nauta, Maarten; Christensen, B. B.

    2012-01-01

    of up to 110 pork slices. Significance and Impact of the Study: The proposed model provides an important tool to examine the effect of cross‐contamination in quantitative microbial risk assessments and might also be applied to various other food processes where cross‐contamination is involved.......Aims: The aim of this study was to develop a model to predict cross‐contamination of Salmonella during grinding of pork. Methods and Results: Transfer rates of Salmonella were measured in three experiments, where between 10 and 20 kg meat was ground into 200‐g portions. In each experiment, five...... pork slices of about 200 g per slice were inoculated with 8–9 log‐units of Salmonella Typhimurium DT104 and used for building up the contamination in the grinder. Subsequently, Salmonella‐free slices were ground and collected as samples of c. 200 g minced pork. Throughout the process, representative...

  7. Recombinant Salmonella enterica Serovar Typhimurium as a Vaccine Vector for HIV-1 Gag

    Directory of Open Access Journals (Sweden)

    Nyasha Chin'ombe

    2013-08-01

    Full Text Available The HIV/AIDS epidemic remains a global health problem, especially in Sub-Saharan Africa. An effective HIV-1 vaccine is therefore badly required to mitigate this ever-expanding problem. Since HIV-1 infects its host through the mucosal surface, a vaccine for the virus needs to trigger mucosal as well as systemic immune responses. Oral, attenuated recombinant Salmonella vaccines offer this potential of delivering HIV-1 antigens to both the mucosal and systemic compartments of the immune system. So far, a number of pre-clinical studies have been performed, in which HIV-1 Gag, a highly conserved viral antigen possessing both T- and B-cell epitopes, was successfully delivered by recombinant Salmonella vaccines and, in most cases, induced HIV-specific immune responses. In this review, the potential use of Salmonella enterica serovar Typhimurium as a live vaccine vector for HIV-1 Gag is explored.

  8. Role of T3SS-1 SipD Protein in Protecting Mice against Non-typhoidal Salmonella Typhimurium.

    Directory of Open Access Journals (Sweden)

    Bakhos Jneid

    2016-12-01

    Full Text Available Salmonella enterica species are enteric pathogens that cause severe diseases ranging from self-limiting gastroenteritis to enteric fever and sepsis in humans. These infectious diseases are still the major cause of morbidity and mortality in low-income countries, especially in children younger than 5 years and immunocompromised adults. Vaccines targeting typhoidal diseases are already marketed, but none protect against non-typhoidal Salmonella. The existence of multiple non-typhoidal Salmonella serotypes as well as emerging antibiotic resistance highlight the need for development of a broad-spectrum protective vaccine. All Salmonella spp. utilize two type III Secretion Systems (T3SS 1 and 2 to initiate infection, allow replication in phagocytic cells and induce systemic disease. T3SS-1, which is essential to invade epithelial cells and cross the barrier, forms an extracellular needle and syringe necessary to inject effector proteins into the host cell. PrgI and SipD form, respectively, the T3SS-1 needle and the tip complex at the top of the needle. Because they are common and highly conserved in all virulent Salmonella spp., they might be ideal candidate antigens for a subunit-based, broad-spectrum vaccine.We investigated the immunogenicity and protective efficacy of PrgI and SipD administered by subcutaneous, intranasal and oral routes, alone or combined, in a mouse model of Salmonella intestinal challenge. Robust IgG (in all immunization routes and IgA (in intranasal and oral immunization routes antibody responses were induced against both proteins, particularly SipD. Mice orally immunized with SipD alone or SipD combined with PrgI were protected against lethal intestinal challenge with Salmonella Typhimurium (100 Lethal Dose 50% depending on antigen, route and adjuvant.Salmonella T3SS SipD is a promising antigen for the development of a protective Salmonella vaccine, and could be developed for vaccination in tropical endemic areas to control

  9. Effects of dietary clays on performance and intestinal mucus barrier of broiler chicks challenged with Salmonella enterica serovar Typhimurium and on goblet cell function in vitro.

    Science.gov (United States)

    Almeida, J A S; Ponnuraj, N P; Lee, J J; Utterback, P; Gaskins, H R; Dilger, R N; Pettigrew, J E

    2014-04-01

    In vivo and in vitro experiments were conducted to test for beneficial effects of dietary clays on broiler chicks challenged with Salmonella enterica serovar Typhimurium and to explore potential mechanisms. First, two hundred forty 1-d-old male broilers (initial BW: 41.6 ± 0.4 g) were allotted in a 2 × 4 factorial arrangement in a randomized complete block design. There were 2 infection treatments (with or without Salmonella) and 4 diets: basal (BAS), 0.3% smectite A (SMA), 0.3% smectite B, and 0.3% zeolite. The Salmonella reduced (P clay largely restored it (challenge × diet interaction, P clays (P clays restored the growth depression caused by Salmonella, and changes in goblet cell function may contribute to the benefits of one of the clays, specifically SMA.

  10. Elucidation of the outer membrane proteome of Salmonella enterica serovar Typhimurium utilising a lipid-based protein immobilization technique

    Directory of Open Access Journals (Sweden)

    Appleton Hazel

    2010-02-01

    Full Text Available Abstract Background Salmonella enterica serovar Typhimurium (S. Typhimurium is a major cause of human gastroenteritis worldwide. The outer membrane proteins expressed by S. Typhimurium mediate the process of adhesion and internalisation within the intestinal epithelium of the host thus influencing the progression of disease. Since the outer membrane proteins are surface-exposed, they provide attractive targets for the development of improved antimicrobial agents and vaccines. Various techniques have been developed for their characterisation, but issues such as carryover of cytosolic proteins still remain a problem. In this study we attempted to characterise the surface proteome of S. Typhimurium using Lipid-based Protein Immobilisation technology in the form of LPI™ FlowCells. No detergents are required and no sample clean up is needed prior to downstream analysis. The immobilised proteins can be digested with proteases in multiple steps to increase sequence coverage, and the peptides eluted can be characterised directly by liquid chromatography - tandem mass spectrometry (LC-MS/MS and identified from mass spectral database searches. Results In this study, 54 outer membrane proteins, were identified with two or more peptide hits using a multi-step digest approach. Out of these 28 were lipoproteins, nine were involved in transport and three with enzyme activity These included the transporters BtuB which is responsible for the uptake of vitamin B12, LamB which is involved in the uptake of maltose and maltodextrins and LolB which is involved in the incorporation of lipoproteins in the outer membrane. Other proteins identified included the enzymes MltC which may play a role in cell elongation and division and NlpD which is involved in catabolic processes in cell wall formation as well as proteins involved in virulence such as Lpp1, Lpp2 and OmpX. Conclusion Using a multi-step digest approach the LPI™ technique enables the incorporation of a

  11. Public health surveillance in the UK revolutionises our understanding of the invasive Salmonella Typhimurium epidemic in Africa.

    Science.gov (United States)

    Ashton, Philip M; Owen, Siân V; Kaindama, Lukeki; Rowe, Will P M; Lane, Chris R; Larkin, Lesley; Nair, Satheesh; Jenkins, Claire; de Pinna, Elizabeth M; Feasey, Nicholas A; Hinton, Jay C D; Dallman, Timothy J

    2017-10-31

    The ST313 sequence type of Salmonella Typhimurium causes invasive non-typhoidal salmonellosis and was thought to be confined to sub-Saharan Africa. Two distinct phylogenetic lineages of African ST313 have been identified. We analysed the whole genome sequences of S. Typhimurium isolates from UK patients that were generated following the introduction of routine whole-genome sequencing (WGS) of Salmonella enterica by Public Health England in 2014. We found that 2.7% (84/3147) of S. Typhimurium from patients in England and Wales were ST313 and were associated with gastrointestinal infection. Phylogenetic analysis revealed novel diversity of ST313 that distinguished UK-linked gastrointestinal isolates from African-associated extra-intestinal isolates. The majority of genome degradation of African ST313 lineage 2 was conserved in the UK-ST313, but the African lineages carried a characteristic prophage and antibiotic resistance gene repertoire. These findings suggest that a strong selection pressure exists for certain horizontally acquired genetic elements in the African setting. One UK-isolated lineage 2 strain that probably originated in Kenya carried a chromosomally located bla CTX-M-15, demonstrating the continual evolution of this sequence type in Africa in response to widespread antibiotic usage. The discovery of ST313 isolates responsible for gastroenteritis in the UK reveals new diversity in this important sequence type. This study highlights the power of routine WGS by public health agencies to make epidemiologically significant deductions that would be missed by conventional microbiological methods. We speculate that the niche specialisation of sub-Saharan African ST313 lineages is driven in part by the acquisition of accessory genome elements.

  12. Public health surveillance in the UK revolutionises our understanding of the invasive Salmonella Typhimurium epidemic in Africa

    Directory of Open Access Journals (Sweden)

    Philip M. Ashton

    2017-10-01

    Full Text Available Abstract Background The ST313 sequence type of Salmonella Typhimurium causes invasive non-typhoidal salmonellosis and was thought to be confined to sub-Saharan Africa. Two distinct phylogenetic lineages of African ST313 have been identified. Methods We analysed the whole genome sequences of S. Typhimurium isolates from UK patients that were generated following the introduction of routine whole-genome sequencing (WGS of Salmonella enterica by Public Health England in 2014. Results We found that 2.7% (84/3147 of S. Typhimurium from patients in England and Wales were ST313 and were associated with gastrointestinal infection. Phylogenetic analysis revealed novel diversity of ST313 that distinguished UK-linked gastrointestinal isolates from African-associated extra-intestinal isolates. The majority of genome degradation of African ST313 lineage 2 was conserved in the UK-ST313, but the African lineages carried a characteristic prophage and antibiotic resistance gene repertoire. These findings suggest that a strong selection pressure exists for certain horizontally acquired genetic elements in the African setting. One UK-isolated lineage 2 strain that probably originated in Kenya carried a chromosomally located bla CTX-M-15, demonstrating the continual evolution of this sequence type in Africa in response to widespread antibiotic usage. Conclusions The discovery of ST313 isolates responsible for gastroenteritis in the UK reveals new diversity in this important sequence type. This study highlights the power of routine WGS by public health agencies to make epidemiologically significant deductions that would be missed by conventional microbiological methods. We speculate that the niche specialisation of sub-Saharan African ST313 lineages is driven in part by the acquisition of accessory genome elements.

  13. Biofilm formation by multidrug-resistant Salmonella enterica serotype typhimurium phage type DT104 and other pathogens.

    Science.gov (United States)

    Kim, Shin-Hee; Wei, Cheng-i

    2007-01-01

    The biofilm-forming capability of Salmonella enterica serotypes Typhimurium and Heidelberg, Pseudomonas aeruginosa, Listeria monocytogenes, Escherichia coli O157:H7, Klebsiella pneumoniae, and Acinetobacter baumannii isolated from humans, animal farms, and retail meat products was evaluated by using a microplate assay. The tested bacterial species showed interstrain variation in their capabilities to form biofilms. Strong biofilm-forming strains of S. enterica serotypes, E. coli O157: H7, P. aeruginosa, K. pneumoniae, and A. baumannii were resistant to at least four of the tested antibiotics. To understand their potential in forming biofilms in food-processing environments, the strong biofilm formers grown in beef, turkey, and lettuce broths were further investigated on stainless steel and glass surfaces. Among the tested strains, Salmonella Typhimurium phage type DT104 (Salmonella Typhimurium DT104) isolated from retail beef formed the strongest biofilm on stainless steel and glass in beef and turkey broths. K. pneumoniae, L. monocytogenes, and P. aeruginosa were also able to form strong biofilms on the tested surface materials. Salmonella Typhimurium DT104 developed a biofilm on stainless steel in beef and turkey broths through (i) initial attachment to the surface, (ii) formation of microcolonies, and (iii) biofilm maturation. These findings indicated that Salmonella Typhimurium DT104 alongwith other bacterial pathogens could be a source of cross-contamination during handling and processing of food.

  14. Development of multiplex PCR assay for simultaneous detection of Salmonella genus, Salmonella subspecies I, Salm. Enteritidis, Salm. Heidelberg and Salm. Typhimurium.

    Science.gov (United States)

    Park, S H; Ricke, S C

    2015-01-01

    The aim of this research was to develop multiplex PCR assay that could simultaneously detect Salmonella genus, Salmonella subsp. I, Salm. Enteritidis, Heidelberg and Typhimurium because these Salmonella serovars are the most common isolates associated with poultry products. Five primers were utilized to establish multiplex PCR and applied to Salmonella isolates from chickens and farm environments. These isolates were identified as Salmonella subsp. I and 16 of 66 isolates were classified as Salm. Enteritidis, while Heidelberg or Typhimurium was not detected. We also spiked three Salmonella strains on chicken breast meat to evaluate the specificity and sensitivity of multiplex PCR as well as qPCR to optimize quantification of Salmonella in these samples. The optimized multiplex PCR and qPCR could detect approx. 2·2 CFU of Salmonella per gram after 18 h enrichment. The multiplex PCR and qPCR would provide rapid and consistent results. Also, these techniques would be useful for the detection and quantification of Salmonella in contaminated poultry, foods and environmental samples. The strategy for the rapid detection of Salmonella serovars in poultry is needed to further reduce the incidence of salmonellosis in humans. The optimized multiplex PCR will be useful to detect prevalent Salmonella serovars in poultry products. © 2014 The Society for Applied Microbiology.

  15. Salmonella typhimurium and Listeria monocytogenes Growth Inhibition by Zataria multiflora Essential Oil in Ground Meat

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    Asma Afshari

    2017-09-01

    Full Text Available Background: Zataria multiflora boiss is a member of Lamiaceae family with antibacterial, antifungal, and antioxidant activity. The aim of this study was to evaluate chemical composition and antibacterial effect of Zataria multiflora essential oil against two foodborne pathogens in meat. Methods: The inhibitory effect of Zataria multiflora essential oil (Minimum inhibitory concentration and Minimum bactericidal concentration was evaluated against Salmonella typhimurium and Listeria monocytogenes, inoculated in ground beef meat after 3, 5, 7 and 9 days of storage. Results: Result revealed 26 various compounds, representing 96.27% of total oil. Thymol was the most abundant compound among all constituents (29.2%. A significant reduction was observed in Salmonella typhimurium when adding 1 and 2% Zataria multiflora (p<0.05 compared with 0.5% and 1% concentrations during 9 days of storage. Listeria monocytogenes significantly decreased in treatments with 0.5%, 1 and 2% of Zataria multiflora essential oil. Conclusion: Zataria multiflora has an inhibitory effect on the growth of L. monocytogenes and in higher concentrations on the growth of S. typhimurium and can be used as a natural preservative in order to retard the growth of food-borne pathogens.

  16. Rapid and sensitive magnetoelastic biosensors for the detection of Salmonella typhimurium in a mixed microbial population.

    Science.gov (United States)

    Guntupalli, R; Lakshmanan, R S; Hu, J; Huang, T S; Barbaree, J M; Vodyanoy, V; Chin, B A

    2007-07-01

    In this article, we report the results of an investigation into the performance of a wireless, magnetoelastic biosensor designed to selectively detect Salmonella typhimurium in a mixed microbial population. The Langmuir-Blodgett (LB) monolayer technique was employed for antibody (specific to Salmonella sp.) immobilization on rectangular shaped strip magnetoelastic sensors (2 x 0.4 x 0.015 mm). Bacterial binding to the antibody on the sensor surface changes the resonance parameters, and these changes were quantified as a shift in the sensor's resonance frequency. Response of the sensors to increasing concentrations (5 x 10(1) to 5 x 10(8) cfu/ml) of S. typhimurium in a mixture of extraneous foodborne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes) was studied. A detection limit of 5 x 10(3) cfu/ml and a sensitivity of 139 Hz/decade were observed for the 2 x 0.4 x 0.015 mm sensors. Binding kinetics studies have shown that the dissociation constant (K(d)) and the binding valencies for water samples spiked with S. typhimurium was 435 cfu/ml and 2.33 respectively. The presence of extraneous microorganisms in the mixture did not produce an appreciable change in the biosensor's dose response behavior.

  17. Macroporous silicon based simple and efficient trapping platform for electrical detection of Salmonella typhimurium pathogens.

    Science.gov (United States)

    Das, R Dev; RoyChaudhuri, C; Maji, S; Das, S; Saha, H

    2009-07-15

    A thermally oxidized macroporous silicon substrate with simple electrode structure without interdigitated electrode configuration has been reported for the detection of Salmonella typhimurium pathogens by electrical impedance measurement using antibody-antigen binding method. Macroporous silicon which has been fabricated by anodizing silicon in HF and DMF solution is a regular network of pores of 1-2 microm diameters. This has been thermally oxidized to yield the surface hydrophilic for antibody immobilization as well as provide suitable electrical insulation of the metal contacts from the underlying conducting silicon substrate. The macroporous silicon surface has been immobilized by Salmonella specific antibody and has been tested with different concentration of S. typhimurium pathogens in phosphate buffer solution (PBS). It has been found that such macroporous silicon substrates is capable of detecting down to 10(3)CFU/ml in pure culture using a 3 mm x 1 mm electrode structure with a wide spacing of 1mm. The selectivity of the macroporous silicon substrates with reference to S. typhimurium has been tested to be satisfactory by carrying out controlled experiments with Escherichia coli O157:H7.

  18. EVALUATION OF AN O-ANTIGEN ELISA FOR SCREENING CATTLE HERDS FOR SALMONELLA-TYPHIMURIUM

    DEFF Research Database (Denmark)

    Hoorfar, Jeffrey; Bitsch, V.

    1995-01-01

    A total of 2585 serum samples from 62 dairy herds located in four different regions of Denmark were tested in an O-antigen (0:1,4,5,12)-based ELISA for the detection of antibodies against Salmonella typhimurium. Ten closed herds from an island with no reported occurrence of salmonellosis...... the salmonellosis-free island were ELISA-negative, and all but one of the 12 S typhimurium-infected herds were ELISA-positive, which resulted in a herd test sensitivity of 0.92 and herd test specificity of 1.0. Eleven of the 12 S typhimurium-infected herds were negative in a blocking ELISA based on a monoclonal...... antibody to the 0:9 antigen of the serogroup D salmonellas, indicating the possibility of rapid serogroup-specific screening of herds by means of these two tests. Ten other randomly selected herds with clinical outbreaks of S dublin were all, to a large extent, positive in the 0:1,4,5,12-ELISA, whereas a S...

  19. 15-Deoxy-Δ12,14-prostaglandin J2 inhibits macrophage colonization by Salmonella enterica serovar Typhimurium.

    Directory of Open Access Journals (Sweden)

    Michelle M C Buckner

    Full Text Available 15-deoxy-Δ(12,14-prostaglandin J2 (15d-PGJ2 is an anti-inflammatory downstream product of the cyclooxygenase enzymes. It has been implicated to play a protective role in a variety of inflammatory mediated diseases, including rheumatoid arthritis, neural damage, and myocardial infarctions. Here we show that 15d-PGJ2 also plays a role in Salmonella infection. Salmonella enterica Typhimurium is a Gram-negative facultative intracellular pathogen that is able to survive and replicate inside phagocytic immune cells, allowing for bacterial dissemination to systemic sites. Salmonella species cause a wide range of morbidity and mortality due to gastroenteritis and typhoid fever. Previously we have shown that in mouse models of typhoid fever, Salmonella infection causes a major perturbation in the prostaglandin pathway. Specifically, we saw that 15d-PGJ2 production was significantly increased in both liver and feces. In this work we show that 15d-PGJ2 production is also significantly increased in macrophages infected with Salmonella. Furthermore, we show that the addition of 15d-PGJ2 to Salmonella infected RAW264.7, J774, and bone marrow derived macrophages is sufficient to significantly reduce bacterial colonization. We also show evidence that 15d-PGJ2 is reducing bacterial uptake by macrophages. 15d-PGJ2 reduces the inflammatory response of these infected macrophages, as evidenced by a reduction in the production of cytokines and reactive nitrogen species. The inflammatory response of the macrophage is important for full Salmonella virulence, as it can give the bacteria cues for virulence. The reduction in bacterial colonization is independent of the expression of Salmonella virulence genes SPI1 and SPI2, and is independent of the 15d-PGJ2 ligand PPAR-γ. 15d-PGJ2 also causes an increase in ERK1/2 phosphorylation in infected macrophages. In conclusion, we show here that 15d-PGJ2 mediates the outcome of bacterial infection, a previously unidentified

  20. Phage-based magnetoelastic sensor for the detection of Salmonella typhimurium

    Science.gov (United States)

    Lakshmanan, Ramji S.

    In recent years, food-borne illness have garnered the attention of mainstream America with calls now coming from the media for more inspections to ensure the safety of our food supply. Food borne illness from the ingestion of S. typhimurium has been of great concern due to its common occurrence in food products of daily consumption. Annually approximately 80 million cases of food poisoning are reported in the United States alone. The ever growing need for rapid detection of pathogenic microorganisms present in food, environmental and clinical samples has invoked an increased interest in research efforts towards the development of novel diagnostic methodologies. Currently, the detection of bacteria in contaminated food relies on conventional microbiological methods that are time consuming and manpower intensive. This study presents the results of the characterization of a phage-based magnetoelastic biosensor for the detection of Salmonella typhimurium . This affinity-based biosensensor is comprised of a magnetoelastic material as the transducer and filamentous phage as the bio-recognition element. Magnetoelastic materials are ferromagnetic amorphous alloys that change dimensions in the presence of a magnetic field. This effect in combination with the reverse effect (inverse magnetostriction) is utilized in a typical sensor application. A time varying magnetic field causes these sensors to oscillate at a characteristic resonance frequency. The characteristic resonance frequency is dependent on the initial dimensions and physical properties of the material. These materials are of particular interest owing to their unique capability to perform remote (without direct wire contacts to the sensor) sensing, making in-vivo detection and detection in closed containers possible. The phage-immobilized magnetoelastic biosensor was characterized for specificity; dose response in water, spiked apple juice and in spiked milk; selectivity; and longevity. The sensor's sensitivity is

  1. L-asparaginase II produced by Salmonella typhimurium inhibits T cell responses and mediates virulence.

    Science.gov (United States)

    Kullas, Amy L; McClelland, Michael; Yang, Hee-Jeong; Tam, Jason W; Torres, AnnMarie; Porwollik, Steffen; Mena, Patricio; McPhee, Joseph B; Bogomolnaya, Lydia; Andrews-Polymenis, Helene; van der Velden, Adrianus W M

    2012-12-13

    Salmonella enterica serovar Typhimurium avoids clearance by the host immune system by suppressing T cell responses; however, the mechanisms that mediate this immunosuppression remain unknown. We show that S. Typhimurium inhibit T cell responses by producing L-Asparaginase II, which catalyzes the hydrolysis of L-asparagine to aspartic acid and ammonia. L-Asparaginase II is necessary and sufficient to suppress T cell blastogenesis, cytokine production, and proliferation and to downmodulate expression of the T cell receptor. Furthermore, S. Typhimurium-induced inhibition of T cells in vitro is prevented upon addition of L-asparagine. S. Typhimurium lacking the L-Asparaginase II gene (STM3106) are unable to inhibit T cell responses and exhibit attenuated virulence in vivo. L-Asparaginases are used to treat acute lymphoblastic leukemia through mechanisms that likely involve amino acid starvation of leukemic cells, and these findings indicate that pathogens similarly use L-asparagine deprivation to limit T cell responses. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Antibiotic Resistance Pattern and Biofilm Formation Ability of Clinically Isolates of Salmonella enterica Serotype typhimurium

    Directory of Open Access Journals (Sweden)

    Hadi Ghasemmahdi

    2015-05-01

    Full Text Available Background: The emergence of antimicrobial-resistant bacteria with biofilm formation ability may be a major threat to public health and food safety and sanitation. Objectives: The aim of this study was to determine antibiotic resistance patterns and biofilm production characteristics of Salmonella typhimurium isolated from different species of birds. Materials and Methods: The antibiotic resistance patterns of 38 pre-identified isolates were screened by standard Kirby-Bauer disc-diffusion method performed on Mueller–Hinton agar to a panel of 17 antibiotics. The extent of biofilm formation was measured by Microtiter plate (MTP-based systems. Results: The highest antimicrobial resistance was detected against nalidixic acid (97%, followed by doxycycline (86%, colistin (84%, streptomycin (84% and tetracycline (84%. All isolates were sensitive to amikacin (100% and 97% and 95% of the isolates were sensitive to ceftazidime and ceftriaxone, respectively. Twenty one different antibiotic resistance patterns were observed among S. typhimurium isolates. According to the results of the microtitre plate biofilm assay, there was a wide variation in biofilm forming ability among S. typhimurium isolates. Most of the isolates (60.52% were not capable of producing biofilm, while 26.31%, 7.89%, and 5.26% isolates were weak, strong and moderate biofilm producers, respectively. Conclusions: It was concluded that nearly all S. typhimurium isolates revealed a high multiple antibiotic resistant with low biofilm forming capabilities which proposed low association between biofilm formation and antibiotic resistance of a major food important pathogen.

  3. Epidemiology of Salmonella typhimurium O:4-12 infection in Norway: evidence of transmission from an avian wildlife reservoir.

    Science.gov (United States)

    Kapperud, G; Stenwig, H; Lassen, J

    1998-04-15

    In 1987, a nationwide outbreak of Salmonella typhimurium O:4-12 infection traced to contaminated chocolate bars occurred in Norway. In the 5 years after the outbreak, elevated numbers of sporadic cases caused by the epidemic strain of Salmonella were detected, followed by a decline in subsequent years. To characterize the epidemiology of this infection, the authors analyzed information concerning all sporadic cases reported in Norway from 1966 to 1996. Of the 153 patients infected by the outbreak strain, 43% were less than 5 years of age, and only three persons had acquired the infection abroad. In contrast, 46% of the cases attributable to other S. typhimurium O:4-12 variants and 90% of the total number of Salmonella infections were related to foreign travel. A distinct seasonality was observed: 76% of the cases appeared between January and April. At the same time of year, the epidemic strain was regularly encountered as the etiologic agent of fatal salmonellosis among wild passerine birds, suggesting an epidemiologic link between the avian and human cases. The strain was rarely isolated from other sources. From 1990 to 1992, the authors conducted a prospective case-control study of sporadic indigenous infections to identify risk factors and obtain guidance for preventive efforts. Forty-one case-patients, each matched by age, sex, and geographic area with two population controls, were enrolled. In conditional logistic regression analysis, the following environmental factors were independently related to an increased risk of infection: drinking untreated water, having direct contact with wild birds or their droppings, and eating snow, sand, or soil. Cases were also more likely than controls to report having antecedent or concurrent medical disorders. Forty-six percent of the study patients were hospitalized for their salmonellosis.

  4. Tackling the issue of environmental survival of live Salmonella Typhimurium vaccines: deletion of the lon gene.

    Science.gov (United States)

    Leyman, Bregje; Boyen, Filip; Van Parys, Alexander; Verbrugghe, Elin; Haesebrouck, Freddy; Pasmans, Frank

    2012-12-01

    Vaccination is an important measure to control Salmonella contamination in the meat production chain. A previous study showed that both the ΔrfaJ and ΔrfaL strains are suitable markers and allow serological differentiation of infected and vaccinated animals. The aim of this study was to verify whether deletion of the lon gene in a Salmonella Typhimurium ΔrfaJ marker strain resulted in decreased environmental survival. Our results indicate that deletion of the lon gene in the ΔrfaJ strain did not affect invasiveness in IPEC-J2 cells and resulted in an increased susceptibility to UV, disinfectants (such as hydrogen peroxide and tosylchloramide sodium) and citric acid. Immunization of pigs with inactivated ΔrfaJ or ΔlonΔrfaJ vaccines allowed differentiation of infected and vaccinated pigs. Furthermore, deletion of the lon gene did not reduce the protection conferred by live wild type or ΔrfaJ vaccines against subsequent challenge with a virulent Salmonella Typhimurium strain in BALB/c mice. Based on our results in mice, we conclude that deletion of lon in ΔrfaJ contributes to environmental safety of the ΔrfaJ DIVA strain. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Photonic plasmid stability of transformed Salmonella Typhimurium: A comparison of three unique plasmids

    Directory of Open Access Journals (Sweden)

    Lay Donald

    2009-07-01

    Full Text Available Abstract Background Acquiring a highly stable photonic plasmid in transformed Salmonella Typhimurium for use in biophotonic studies of bacterial tracking in vivo is critical to experimental paradigm development. The objective of this study was to determine stability of transformed Salmonella Typhimurium (S. typh-lux using three different plasmids and characterize their respective photonic properties. Results In presence of ampicillin (AMP, S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 plasmids exhibited 100% photon-emitting colonies over a 10-d study period. Photon emitters of S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 without AMP selection decreased over time (P 7 to 1 × 109 CFU, P 0.05; although photonic emissions across a range of bacterial concentrations were not different (1 × 104 to 1 × 106 CFU, P > 0.05. For very low density bacterial concentrations imaged in 96 well plates photonic emissions were positively correlated with bacterial concentration (P 3 to 1 × 105 CFU low to high were different in the 96-well plate format (P Conclusion These data characterize photon stability properties for S. typh-lux transformed with three different photon generating plasmids that may facilitate real-time Salmonella tracking using in vivo or in situ biophotonic paradigms.

  6. Type VI secretion system-associated gene clusters contribute to pathogenesis of Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Mulder, David T; Cooper, Colin A; Coombes, Brian K

    2012-06-01

    The enteropathogen Salmonella enterica serovar Typhimurium employs a suite of tightly regulated virulence factors within the intracellular compartment of phagocytic host cells resulting in systemic dissemination in mice. A type VI secretion system (T6SS) within Salmonella pathogenicity island 6 (SPI-6) has been implicated in this process; however, the regulatory inputs and the roles of noncore genes in this system are not well understood. Here we describe four clusters of noncore T6SS genes in SPI-6 based on a comparative relationship with the T6SS-3 of Burkholderia mallei and report that the disruption of these genes results in defects in intracellular replication and systemic dissemination in mice. In addition, we show that the expression of the SPI-6-encoded Hcp and VgrG orthologs is enhanced during late stages of macrophage infection. We identify six regions that are transcriptionally active during cell infections and that have regulatory contributions from the regulators of virulence SsrB, PhoP, and SlyA. We show that levels of protein expression are very weak under in vitro conditions and that expression is not enhanced upon the deletion of ssrB, phoP, slyA, qseC, ompR, or hfq, suggesting an unknown activating factor. These data suggest that the SPI-6 T6SS has been integrated into the Salmonella Typhimurium virulence network and customized for host-pathogen interactions through the action of noncore genes.

  7. Emergence of pulsed electric fields resistance in Salmonella enterica serovar Typhimurium SL1344.

    Science.gov (United States)

    Sagarzazu, N; Cebrián, G; Pagán, R; Condón, S; Mañas, P

    2013-09-02

    In this investigation we selected and isolated a culture derived from Salmonella enterica serovar Typhimurium SL1344 with stable increased resistance to pulsed electric fields (PEF) after repeated rounds of PEF treatment and outgrowth of survivors. The resulting culture showed a higher resistance to PEF treatments under different treatment conditions. The acquisition of PEF resistance was only observed in stationary phase cells. The cytoplasmic membrane of the resistant variant showed a higher resilience against PEF treatments, since a lower permeabilization degree was observed after PEF treatments, in comparison to the parental strain. Resistance to PEF was also accompanied by a higher tolerance to acidic pH, hydrogen peroxide and ethanol, but not to heat. The occurrence of a PEF resistant variant in S. enterica serovar Typhimurium SL1344 emphasizes the need to further study the mechanisms of inactivation and resistance by PEF for an adequate design of safe treatments. © 2013.

  8. Experimental annotation of post-translational features and translated coding regions in the pathogen Salmonella Typhimurium

    Science.gov (United States)

    2011-01-01

    Background Complete and accurate genome annotation is crucial for comprehensive and systematic studies of biological systems. However, determining protein-coding genes for most new genomes is almost completely performed by inference using computational predictions with significant documented error rates (> 15%). Furthermore, gene prediction programs provide no information on biologically important post-translational processing events critical for protein function. Results We experimentally annotated the bacterial pathogen Salmonella Typhimurium 14028, using "shotgun" proteomics to accurately uncover the translational landscape and post-translational features. The data provide protein-level experimental validation for approximately half of the predicted protein-coding genes in Salmonella and suggest revisions to several genes that appear to have incorrectly assigned translational start sites, including a potential novel alternate start codon. Additionally, we uncovered 12 non-annotated genes missed by gene prediction programs, as well as evidence suggesting a role for one of these novel ORFs in Salmonella pathogenesis. We also characterized post-translational features in the Salmonella genome, including chemical modifications and proteolytic cleavages. We find that bacteria have a much larger and more complex repertoire of chemical modifications than previously thought including several novel modifications. Our in vivo proteolysis data identified more than 130 signal peptide and N-terminal methionine cleavage events critical for protein function. Conclusion This work highlights several ways in which application of proteomics data can improve the quality of genome annotations to facilitate novel biological insights and provides a comprehensive proteome map of Salmonella as a resource for systems analysis. PMID:21867535

  9. Influence of the treatment of Listeria monocytogenes and Salmonella enterica serovar Typhimurium with citral on the efficacy of various antibiotics.

    Science.gov (United States)

    Zanini, Surama F; Silva-Angulo, Angela B; Rosenthal, Amauri; Aliaga, Dolores Rodrigo; Martínez, Antonio

    2014-04-01

    The main goal of this work was to study the bacterial adaptive responses to antibiotics induced by sublethal concentration of citral on first-and second-generation cells of Listeria monocytogenes serovar 4b (CECT 4032) and Salmonella enterica serovar Typhimurium (CECT 443). The first-generation cells were not pretreated with citral, while the second-generation cells were obtained from cells previously exposed to citral during 5 h. The trials were conducted at 37°C. The presence of citral in the culture medium and the antibiotic strips resulted in a reduced minimum inhibitory concentration (MIC) for the first-generation cells of Listeria monocytogenes serovar 4b and Salmonella Typhimurium. This result was observed for almost all the antibiotics, compared with the same microorganisms of the control group (without citral), which could represent an additive effect. For Listeria serovar 4b, the second-generation cells of the test group maintained the same susceptibility to antibiotics compared with cells in the control group and in the test group of the first generation. The second-generation cells of the control group indicated that the Salmonella Typhimurium maintained the same sensitivity to the antibiotics tested compared with the first generation of this group, except in the case of erythromycin, which exhibited an increased MIC value. With respect to the second-generation cells of Salmonella Typhimurium, the presence of citral determined a decrease in the antibiotic susceptibility for almost all of the antibiotics, except colistin, compared with the first-generation of the test group, which can be seen by increase of MIC values. In conclusion, the presence of citral in the culture medium of Listeria 4b and Salmonella Typhimurium increased the antibiotic susceptibility of the first generations, while we observed an increase in antibiotic resistance in the second generation of Salmonella Typhimurium.

  10. Simultaneous oral administration of Salmonella Infantis and S. Typhimurium in chicks.

    Science.gov (United States)

    Murakami, Koichi; Maeda-Mitani, Eriko; Onozuka, Daisuke; Noda, Tamie; Sera, Nobuyuki; Kimura, Hirokazu; Fujimoto, Shuji; Murakami, Satoshi

    2017-01-01

    To confirm the hypothesis that Salmonella enterica subspecies enterica serovar (S.) Infantis has higher basic reproductive rates in chicks compared with other Salmonella serovars, 1-day-old specific-pathogen-free chicks (n = 8) were challenged simultaneously with S. Infantis and S. Typhimurium per os. Challenged chicks (Group A) were then housed with non-infected chicks (Group B, n = 4) for 6 days (from 2 to 8 days of age). Group B birds were then housed with other non-infected birds (Group C, n = 4), which were then transferred to cages containing a further group of untreated chicks (Group D, n = 2). A control group consisting of four non-infected chicks was used for comparison. All chickens were humanely sacrificed at 18 days of age, and Salmonella from bowel and liver samples were enumerated. Both serovars were isolated from all groups except the control group. S. Typhimurium was isolated at a greater frequency than S. Infantis from the bowel samples of chicks from Groups B, C and D, while no differences in colonisation rates were observed between the two serovars in liver samples from Groups B, C and D. S. Typhimurium, but not S. Infantis, was immunohistochemically detected in the lamina propria of the cecum and rectum in five birds of Group A. Despite the competitive administration, neither of the two serovars completely excluded the other, and no differences were observed in basic reproductive rates between the two serovars. These findings, together with data from previous studies, suggest that the initial quantitative domination of S. Infantis in chicken flocks may explain why this serovar is predominant in broiler chickens.

  11. Identification of novel factors involved in modulating motility of Salmonella enterica serotype typhimurium.

    Directory of Open Access Journals (Sweden)

    Lydia M Bogomolnaya

    Full Text Available Salmonella enterica serotype Typhimurium can move through liquid using swimming motility, and across a surface by swarming motility. We generated a library of targeted deletion mutants in Salmonella Typhimurium strain ATCC14028, primarily in genes specific to Salmonella, that we have previously described. In the work presented here, we screened each individual mutant from this library for the ability to move away from the site of inoculation on swimming and swarming motility agar. Mutants in genes previously described as important for motility, such as flgF, motA, cheY are do not move away from the site of inoculation on plates in our screens, validating our approach. Mutants in 130 genes, not previously known to be involved in motility, had altered movement of at least one type, 9 mutants were severely impaired for both types of motility, while 33 mutants appeared defective on swimming motility plates but not swarming motility plates, and 49 mutants had reduced ability to move on swarming agar but not swimming agar. Finally, 39 mutants were determined to be hypermotile in at least one of the types of motility tested. Both mutants that appeared non-motile and hypermotile on plates were assayed for expression levels of FliC and FljB on the bacterial surface and many of them had altered levels of these proteins. The phenotypes we report are the first phenotypes ever assigned to 74 of these open reading frames, as they are annotated as 'hypothetical genes' in the Typhimurium genome.

  12. Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, George; Brown, Roslyn N.; Gustin, Jean K.; Stufkens, Afke; Shaikh-Kidwai, Afshan S.; Li, Jie; McDermott, Jason E.; Brewer, Heather M.; Schepmoes, Athena A.; Smith, Richard D.; Adkins, Joshua N.; Heffron, Fred

    2011-01-01

    The intracellular pathogen Salmonella enterica serovar Typhimurium is a leading cause of acute gastroenteritis in the world. This pathogen has two type-III secretion systems (TTSS) necessary for virulence that are encoded in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) and are expressed during extracellular or intracellular infectious states, respectively, to deliver virulence factors (effectors) to the host cell cytoplasm. While many have been identified and at least partially characterized, the full repertoire of effectors has not been catalogued. In this mass spectrometry-based proteomics study, we identified effector proteins secreted under minimal acidic medium growth conditions that induced the SPI-2 TTSS and its effectors, and compared the secretome from the parent strain to the secretome from strains missing either essential (SsaK) or regulatory components (SsaL) of the SPI-2 secretion apparatus. We identified 75% of the known TTSS effector repertoire. Excluding translocon components, 95% of the known effectors were biased for identification in the ssaL mutant background, which demonstrated that SsaL regulates SPI-2 type III secretion. To confirm secretion to animal cells, we made translational fusions of several of the best candidates to the calmodulin-dependent adenylate cyclase of Bordetella pertussis and assayed cAMP levels of infected J774 macrophage-like cells. From these infected cells we identified six new TTSS effectors and two others that are secreted independent of TTSS. Our results substantiate reports of additional secretion systems encoded by Salmonella other than TTSS.

  13. Survival of Escherichia coli and Salmonella Typhimurium in slurry applied to clay soil on a Danish swine farm

    DEFF Research Database (Denmark)

    Boes, J.; Alban, L.; Bagger, J.

    2005-01-01

    the survival times of E. coli and Salmonella in the soil surface following deposition of naturally contaminated pig slurry; and (3) simulate survival of Salmonella in different infection levels using E. coli data as input estimates. Slurry was deposited by four different methods: (1) hose applicator on black......A pilot study was carried out on a Danish swine farm infected with multi-resistant Salmonella Typhimurium DT104 (MRDT104). We aimed to (1) investigate to which degree the decline of Escherichia coli and Salmonella in swine slurry applied to farmland depended on the application method; (2) estimate...... and Salmonella could not be detected at all in soil following treatment 1. Following the other treatments, E. coli was not detected in soil samples after day 21 and Salmonella was no longer detected after day 7. Simulation results showed that clinical (4 log CFU g(-1)) and sub-clinical Salmonella levels (2500...

  14. Characterisation of streptomycin resistance determinants in Danish isolates of Salmonella typhimurium

    DEFF Research Database (Denmark)

    Madsen, Lissi; Aarestrup, Frank Møller; Olsen, John Elmerdahl

    2000-01-01

    Fifty six Danish streptomycin (Sm) resistant isolates of Salmonella enterica serotype Typhimurium from pigs (n=34), calves (n=3) and humans (n=19) were characterised with respect to co-resistances (14 drugs), transferability of Sm-resistance by conjugation, genetic determinants encoding Sm-resistance...... and diversity with respect to localisation of genes in the genome and DNA-sequences. Forty-six strains carried resistance(s) other than Sm-resistance. Nineteen different coresistance patterns were observed and tetracycline was the most commonly observed resistance in these patterns. In 22 of the strains, Sm-resistance...

  15. [A ruptured mycotic aneurysm of the femoral artery due to Salmonella typhimurium].

    Science.gov (United States)

    Calvo Cascallo, J; Mundi Salvadó, N; Cardona Fontanet, M

    1993-01-01

    Mycotic aneurysms of the femoral artery is rare. We report a new case with a mycotic aneurysm of the femoral artery by "Salmonella typhimurium". The surgical operation was performed as surgical emergence for ruptured aneurysm. We did not know the aneurysm infection origin. The treatment of lesions was resection and femoro-femoral bypass with PTFE. The microbiological examination discovered infection material. A posterior bypass infection required a exeresis bypass and new revascularization with iliofemoral saphenous vein bypass by obturator foramen, and antibiotic treatment prolonged.

  16. Effect of lipopolysaccharide mutations on recipient ability of Salmonella typhimurium for incompatibility group H plasmids.

    OpenAIRE

    Sherburne, C; Taylor, D E

    1997-01-01

    Previous investigations of the incompatibility group F, P, and I plasmid systems revealed the important role of the outer membrane components in the conjugal transfer of these plasmids. We have observed variability in transfer frequency of three incompatibility group H plasmids (IncHI1 plasmid R27, IncHI2 plasmid R478, and a Tn7 derivative of R27, pDT2454) upon transfer into various Salmonella typhimurium lipopolysaccharide (LPS) mutants derived from a common parental strain, SL1027. Recipien...

  17. Development of an Immunomagnetic Separation Method for Viable Salmonella Typhimurium Detected by Flow Cytometry

    DEFF Research Database (Denmark)

    Ahmed, Shakil; Rubahn, Horst-Günter; Erdmann, Helmut

    2016-01-01

    for detection of food-related bacteria. In this study, a flow cytometry based immunomagnetic separation (IMS) method for the isolation and enrichment of Salmonella Typhimurium from liquid samples was developed and optimized. Both polyclonal and monoclonal antibodies have been used to couple with 1 micron sized...... paramagnetic particles for the preparation of immunomagnetic beads (IMBs). The most suitable antibody was chosen by applying an enzyme linked immunosorbent assay (ELISA), whereas living bacteria were detected by flow cytometry. The parameters for both IMS and flow cytometry e.g., concentration of bead...

  18. A comparative study of thermal and acid inactivation kinetics in fruit juices of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Senftenberg grown at acidic conditions.

    Science.gov (United States)

    Alvarez-Ordóñez, Avelino; Fernández, Ana; Bernardo, Ana; López, Mercedes

    2009-11-01

    Acid and heat inactivation in orange and apple juices of Salmonella enterica serovar Typhimurium Colección Española de Cultivos Tipo (i.e., Spanish Type Culture Collection) 443 (CECT 443) (Salmonella Typhimurium) and S. enterica serovar Senftenberg CECT 4384 (Salmonella Senftenberg) grown in buffered brain heart infusion (pH 7.0) and acidified brain heart infusion up to pH 4.5 with acetic, citric, lactic, and hydrochloric acids was evaluated. Acid adaptation induced an adaptive response that increased the subsequent resistance to extreme pH conditions (pH 2.5) and to heat, although the magnitude of these responses differed between the two isolates and fruit juices. The acid resistance in orange juice for acid-adapted cells (D-values of 28.3-34.5 min for Salmonella Senftenberg and 30.0-39.2 min for Salmonella Typhimurium) resulted to be about two to three times higher than that corresponding to non-acid-adapted cells. In apple juice, acid-adapted Salmonella Senftenberg cells survived better than those of Salmonella Typhimurium, obtaining mean D-values of 114.8 +/- 12.3 and 41.9 +/- 2.5 min, respectively. The thermotolerance of non-acid-adapted Salmonella Typhimurium in orange (D(58)-value: 0.028 min) and apple juices (D(58)-value: 0.10 min) was approximately double for acid-adapted cells. This cross-protection to heat was more strongly expressed in Salmonella Senftenberg. D(58)-values obtained for non-acid-adapted cells in orange (0.11 min) and apple juices (0.19 min) increased approximately 10 and 5 times, respectively, after their growth in acidified media. The conditions prevailing during bacterial growth and heat treatment did not significantly influence the z-values observed (6.0 +/- 0.3 degrees C for Salmonella Typhimurium and 7.0 +/- 0.3 degrees C for Salmonella Senftenberg). The enhanced acid resistance found for both isolates could enable them to survive for prolonged time periods in the gastrointestinal tract, increasing the risk of illness. Further, it

  19. Construction and screening of attenuated ΔphoP/Q Salmonella typhimurium vectored plague vaccine candidates.

    Science.gov (United States)

    Sizemore, Donata R; Warner, Elizabeth A; Lawrence, Julie A; Thomas, Lawrence J; Roland, Kenneth L; Killeen, Kevin P

    2012-03-01

    Preclinical studies evaluating plague vaccine candidates have demonstrated that the F1 and V protein antigens of Yersinia pestis confer protection against challenge from virulent strains. Live-attenuated ΔphoP/Q Salmonella typhimurium recombinants were constructed expressing either F1, V antigens, F1 and V antigens, or a F1-V fusion from Asd (+) balanced-lethal plasmids. To improve antigen delivery, genes encoding plague antigens were modified in order to localize antigens to specific bacterial cellular compartments which include cytoplasmic, outer membrane, or secreted. Candidate vaccine strains were evaluated for growth characteristics, full-length lipopolysaccharide (LPS), plasmid stability, and antigen expression in vitro. Plague vaccine candidate strains with favorable in vitro profiles were evaluated in murine or rabbit preclinical oral immunogenicity studies. Attenuated S. typhimurium strains expressing cytoplasmically localized F1-V and V antigen antigens were more immunogenic than strains that secreted or localized plague antigens to the outer membrane. In particular, S. typhimurium M020 and M023, which express Asd(+)-plasmid derived soluble F1-V and soluble V antigen, respectively, at high levels in the bacterial cell cytoplasm were found to induce the highest levels of plague-specific serum antibodies. To further evaluate balanced-lethal plasmid retention capacity, ΔphoP/Q S. typhimurium PurB(+) and GlnA(+) balanced-lethal plasmid systems harboring F1-V were compared with M020 in vitro and in BALB/c mice in a immunogenicity study. Although there was no detectable difference in plague antigen expression in vitro, S. typhimurium M020 was the most immunogenic plague antigen vector strain evaluated, inducing high-titer serum IgG antibodies specific against F1, V and F1-V.

  20. Growth and virulence properties of biofilm-forming Salmonella enterica serovar typhimurium under different acidic conditions.

    Science.gov (United States)

    Xu, Hua; Lee, Hyeon-Yong; Ahn, Juhee

    2010-12-01

    This study was designed to characterize the viability and potential virulence of bofilm-forming Salmonella enterica serovar Typhimurium under different pH levels, ranging from 5 to 7. The plate count method and real-time reverse transcription-PCR (RT-PCR) were used to evaluate the survival of S. Typhimurium grown in Trypticase soy broth (TSB) adjusted to pH 5, 6, and 7 (TSB-5, TSB-6, and TSB-7, respectively) at 37°C for 10 days. In TSB-5 and TSB-6, the numbers of viable cells estimated by using the real-time RT-PCR were greater than the culturable counts enumerated by the plate count method. Reflectance micro-Fourier transform infrared (micro-FTIR) spectroscopy was used to evaluate the biochemical changes in biofilm cells. Considerable changes in chemical components were observed in the biofilm cells grown in TSB-5 and TSB-6 when compared to the cells grown in TSB-7. The enterotoxin production and invasive ability of planktonic and biofilm S. Typhimurium cells were inferred by the relative levels of expression of stn and invA. The levels of expression of stn and invA were significantly increased in biofilm S. Typhimurium cells grown in TSB-5 (1.9-fold and 3.2-fold) and TSB-6 (2.1-fold and 22.3-fold) after 10 days of incubation. These results suggest that the biofilm-forming S. Typhimurium under different pH levels might change the virulence production and stress response mechanisms.

  1. EL FACTOR TRANSCRIPCIONAL SLYA REGULA LA RESPUESTA A ESPECIES REACTIVAS DE OXIGENO EN SALMONELLA ENTERICA SEROVAR TYPHIMURIUM

    OpenAIRE

    COLLAO ABARCA, BERNARDO GABRIEL

    2014-01-01

    Salmonella Typhimurium (S. Typhimurium) es un patógeno de amplio rango de hospedero capaz de generar fiebre tifoidea en murinos y gastroenteritis en humanos. En el modelo murino, una vez ingerido debe penetrar el intestino donde es fagocitada por células especializadas que incluyen macrófagos, células dendríticas y neutrófilos. Dentro de estas células, la bacteria es intemalizada en un compartimiento denominado vacuola contenedora de Salmonella. Durante esta etapa es sometida a condi...

  2. Investigation of Medium Chain Fatty Acid Feed Supplementation for Reducing Salmonella Typhimurium Colonization in Turkey Poults.

    Science.gov (United States)

    Evans, Nicholas P; Collins, David A; Pierson, Frank William; Mahsoub, Hassan M; Sriranganathan, Nammalwar; Persia, Mike E; Karnezos, Theodore Peter; Sims, Michael D; Dalloul, Rami A

    2017-09-01

    Studies indicate that persistent Salmonella colonization occurs in poultry that are infected early in life, leading to both food safety and public health concerns. Development of improved preharvest Salmonella management strategies is needed to reduce poultry product contamination. The objective of this study was to evaluate the efficacy of a product containing medium chain fatty acids (MCFA) for reducing early Salmonella colonization in turkey poults. Day-of-hatch turkeys were provided a standard starter diet supplemented with MCFA at 0 (negative and positive controls), 1.5, 3, 4.5, or 6 lbs/ton of feed. Positive control and MCFA treated birds were also crop-gavaged with 108 colony forming units (CFU) of bioluminescent Salmonella Typhimurium. Gastrointestinal tissue samples were collected at 3 days postinoculation for bioluminescence imaging (Meckel's diverticulum to the cloaca) and selective enumeration (cecal contents). Quantification of bioluminescence indicated that the 4.5 and 6 lbs/ton MCFA groups had significantly less colonization than the positive control group (p = 0.0412 and p < 0.0001, respectively). Similarly, significantly lower numbers (1-log10 CFU/g reduction) of Salmonella were observed in the ceca of the 6 lbs/ton MCFA group compared to the positive control group (p = 0.0153). These findings indicate that incorporation of MCFA in turkey diets can significantly reduce early Salmonella colonization. In addition, this study highlights the utility of bioluminescence imaging as a screening methodology for assessing the efficacy of treatments that may reduce Salmonella in poultry.

  3. Loss of Multicellular Behavior in Epidemic African Nontyphoidal Salmonella enterica Serovar Typhimurium ST313 Strain D23580

    Directory of Open Access Journals (Sweden)

    Larissa A. Singletary

    2016-03-01

    Full Text Available Nontyphoidal Salmonella enterica serovar Typhimurium is a frequent cause of bloodstream infections in children and HIV-infected adults in sub-Saharan Africa. Most isolates from African patients with bacteremia belong to a single sequence type, ST313, which is genetically distinct from gastroenteritis-associated ST19 strains, such as 14028s and SL1344. Some studies suggest that the rapid spread of ST313 across sub-Saharan Africa has been facilitated by anthroponotic (person-to-person transmission, eliminating the need for Salmonella survival outside the host. While these studies have not ruled out zoonotic or other means of transmission, the anthroponotic hypothesis is supported by evidence of extensive genomic decay, a hallmark of host adaptation, in the sequenced ST313 strain D23580. We have identified and demonstrated 2 loss-of-function mutations in D23580, not present in the ST19 strain 14028s, that impair multicellular stress resistance associated with survival outside the host. These mutations result in inactivation of the KatE stationary-phase catalase that protects high-density bacterial communities from oxidative stress and the BcsG cellulose biosynthetic enzyme required for the RDAR (red, dry, and rough colonial phenotype. However, we found that like 14028s, D23580 is able to elicit an acute inflammatory response and cause enteritis in mice and rhesus macaque monkeys. Collectively, these observations suggest that African S. Typhimurium ST313 strain D23580 is becoming adapted to an anthroponotic mode of transmission while retaining the ability to infect and cause enteritis in multiple host species.

  4. Salmonella Typhimurium, Infantis, Derby, and Enteritidis survival in pasty dulce de leche

    Directory of Open Access Journals (Sweden)

    Débora Rodrigues da Silveira

    2012-12-01

    Full Text Available Dulce de leche is a food obtained by concentration and heating of milk with the addition of sucrose. The common practice of opening the dulce de leche containers in retail markets can lead to food contamination by Salmonella. The objective of this study was to evaluate the survivability of Salmonellaenterica subsp. enterica serotypes Typhimurium, Enteritidis, Infantis and Derby in pasty dulce de leche. Aliquots of this sweet were experimentally contaminated with these microorganisms and later analyzed to evaluate microorganism viability after storage for 0, 1, 2, 3, 5, 10, and 20 days. Salmonella was recovered up to the 20th day. These results are a warning about the need to adopt proper sanitary-hygienic measures for handling and packaging this food aiming at food safety.

  5. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    DEFF Research Database (Denmark)

    Leekitcharoenphon, Pimlapas; Hendriksen, Rene S.; Le Hello, Simon

    2016-01-01

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally...... initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed...... by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes...

  6. Acid tolerance in Salmonella typhimurium induced by culturing in the presence of organic acids at different growth temperatures.

    Science.gov (United States)

    Alvarez-Ordóñez, Avelino; Fernández, Ana; Bernardo, Ana; López, Mercedes

    2010-02-01

    The influence of growth temperature and acidification of the culture medium up to pH 4.25 with acetic, citric, lactic and hydrochloric acids on the growth and subsequent acid resistance at pH 3.0 of Salmonella typhimurium CECT 443 was studied. The minimum pH value which allowed for S. typhimurium growth within the temperature range of 25-37 degrees C was 4.5 when the pH was reduced using citric and hydrochloric acids, and 5.4 and 6.4 when lactic acid and acetic acid were used, respectively. At high (45 degrees C) or low (10 degrees C) temperatures, the growth pH boundary was increased about 1 pH unit. The growth temperature markedly modified the acid resistance of the resulting cells. In all cases, D-values were lower for cells grown at 10 degrees C and significantly increased with increasing growth temperature up to 37 degrees C, at which D-values obtained were up to 10 times higher. Cells grown at 45 degrees C showed D-values similar to those found for cells grown at 25 degrees C. The growth of cells in acidified media, regardless of the pH value, caused an increase in their acid resistance at the four incubation temperatures, although the magnitude of the Acid Tolerance Response (ATR) observed depended on the growth temperature. Acid adapted cultures at 10 degrees C showed D-values ranging from 5.75 to 6.91 min, which turned out to be about 2 times higher than those corresponding to non-acid adapted cultures, while higher temperatures induced an increase in D-values of at least 3.5 times. Another finding was that, while at 10 and 45 degrees C no significant differences among the effect of the different acids tested in inducing an ATR were observed, when cells were grown at 25 and 37 degrees C citric acid generally turned out to be the acid which induced the strongest ATR. Results obtained in this study show that growth temperature is an important factor affecting S. typhimurium acid resistance and could contribute to find new strategies based on intelligent

  7. Mapping the Regulatory Network for Salmonella enterica Serovar Typhimurium Invasion

    Directory of Open Access Journals (Sweden)

    Carol Smith

    2016-09-01

    Full Text Available Salmonella enterica pathogenicity island 1 (SPI-1 encodes proteins required for invasion of gut epithelial cells. The timing of invasion is tightly controlled by a complex regulatory network. The transcription factor (TF HilD is the master regulator of this process and senses environmental signals associated with invasion. HilD activates transcription of genes within and outside SPI-1, including six other TFs. Thus, the transcriptional program associated with host cell invasion is controlled by at least 7 TFs. However, very few of the regulatory targets are known for these TFs, and the extent of the regulatory network is unclear. In this study, we used complementary genomic approaches to map the direct regulatory targets of all 7 TFs. Our data reveal a highly complex and interconnected network that includes many previously undescribed regulatory targets. Moreover, the network extends well beyond the 7 TFs, due to the inclusion of many additional TFs and noncoding RNAs. By comparing gene expression profiles of regulatory targets for the 7 TFs, we identified many uncharacterized genes that are likely to play direct roles in invasion. We also uncovered cross talk between SPI-1 regulation and other regulatory pathways, which, in turn, identified gene clusters that likely share related functions. Our data are freely available through an intuitive online browser and represent a valuable resource for the bacterial research community.

  8. Mutagenicity of rubber vulcanization gases in Salmonella typhimurium.

    Science.gov (United States)

    Hedenstedt, A; Ramel, C; Wachtmeister, C A

    1981-01-01

    Gases formed by rubber and rubber additives in the vulcanization process were collected with a laboratory-scale glass apparatus. Mutagenicity testing of the vulcanization gases by the Salmonella/microsome test was conducted with strains TA1535, TA1538, TA98, and TA100 in the absence and presence of a metabolizing system from rat liver homogenates. The mutagenicity of gases derived by heating chloroprene rubber and ethylene propylene rubber was established with both base substitution- and frameshift-sensitive strains and that of a styrene-butadiene rubber was established with the base substitution-sensitive stain TA100. Tests on pyrolysis gases from a butadiene acrylonitrile rubber revealed only toxic effects. Curing systems, additives, and filling materials from various sources were represented in the material. Gases were collected at temperature levels corresponding to both mixing and curing of these particular rubbers in the industrial operations. Attempts were made to correlate the mutagenicity of the gases to the presence of mutagenic components in the rubber mixtures.

  9. The dark side of the salad: Salmonella typhimurium overcomes the innate immune response of Arabidopsis thaliana and shows an endopathogenic lifestyle.

    Science.gov (United States)

    Schikora, Adam; Carreri, Alessandro; Charpentier, Emmanuelle; Hirt, Heribert

    2008-05-28

    Salmonella enterica serovar typhimurium contaminated vegetables and fruits are considerable sources of human infections. Bacteria present in raw plant-derived nutrients cause salmonellosis, the world wide most spread food poisoning. This facultative endopathogen enters and replicates in host cells and actively suppresses host immune responses. Although Salmonella survives on plants, the underlying bacterial infection mechanisms are only poorly understood. In this report we investigated the possibility to use Arabidopsis thaliana as a genetically tractable host system to study Salmonella-plant interactions. Using green fluorescent protein (GFP) marked bacteria, we show here that Salmonella can infect various Arabidopsis tissues and proliferate in intracellular cellular compartments. Salmonella infection of Arabidopsis cells can occur via intact shoot or root tissues resulting in wilting, chlorosis and eventually death of the infected organs. Arabidopsis reacts to Salmonella by inducing the activation of mitogen-activated protein kinase (MAPK) cascades and enhanced expression of pathogenesis related (PR) genes. The induction of defense responses fails in plants that are compromised in ethylene or jasmonic acid signaling or in the MKK3-MPK6 MAPK pathway. These findings demonstrate that Arabidopsis represents a true host system for Salmonella, offering unique possibilities to study the interaction of this human pathogen with plants at the molecular level for developing novel drug targets and addressing current safety issues in human nutrition.

  10. The dark side of the salad: Salmonella typhimurium overcomes the innate immune response of Arabidopsis thaliana and shows an endopathogenic lifestyle.

    Directory of Open Access Journals (Sweden)

    Adam Schikora

    2008-05-01

    Full Text Available Salmonella enterica serovar typhimurium contaminated vegetables and fruits are considerable sources of human infections. Bacteria present in raw plant-derived nutrients cause salmonellosis, the world wide most spread food poisoning. This facultative endopathogen enters and replicates in host cells and actively suppresses host immune responses. Although Salmonella survives on plants, the underlying bacterial infection mechanisms are only poorly understood. In this report we investigated the possibility to use Arabidopsis thaliana as a genetically tractable host system to study Salmonella-plant interactions. Using green fluorescent protein (GFP marked bacteria, we show here that Salmonella can infect various Arabidopsis tissues and proliferate in intracellular cellular compartments. Salmonella infection of Arabidopsis cells can occur via intact shoot or root tissues resulting in wilting, chlorosis and eventually death of the infected organs. Arabidopsis reacts to Salmonella by inducing the activation of mitogen-activated protein kinase (MAPK cascades and enhanced expression of pathogenesis related (PR genes. The induction of defense responses fails in plants that are compromised in ethylene or jasmonic acid signaling or in the MKK3-MPK6 MAPK pathway. These findings demonstrate that Arabidopsis represents a true host system for Salmonella, offering unique possibilities to study the interaction of this human pathogen with plants at the molecular level for developing novel drug targets and addressing current safety issues in human nutrition.

  11. Comparison of methods for quantitating Salmonella enterica Typhimurium and Heidelberg strain attachment to reusable plastic shipping container coupons and preliminary assessment of sanitizer efficacy.

    Science.gov (United States)

    Shi, Zhaohao; Baker, Christopher A; Lee, Sang In; Park, Si Hong; Kim, Sun Ae; Ricke, Steven C

    2016-09-01

    Salmonella serovars, one of the leading contributors to foodborne illness and are especially problematic for foods that are not cooked before consumption, such as fresh produce. The shipping containers that are used to transport and store fresh produce may play a role in cross contamination and subsequent illnesses. However, methods for quantitatively attached cells are somewhat variable. The overall goal of this study was to compare conventional plating with molecular methods for quantitating attached representative strains for Salmonella Typhimurium and Heidelberg on reusable plastic containers (RPC) coupons, respectively. We attached Salmonella enterica serovar Typhimurium ATCC 14028 and serovar Heidelberg SL486 (parent and an antibiotic resistant marker strain) to plastic coupons (2.54 cm(2)) derived from previously used shipping containers by growing for 72 h in tryptic soy broth. The impact of the concentration of sanitizer on log reductions between unsanitized and sanitized coupons was evaluated by exposing attached S. Typhimurium cells to 200 ppm and 200,000 ppm sodium hypochlorite (NaClO). Differences in sanitizer effectiveness between serovars were also evaluated with attached S. Typhimurium compared to attached S. Heidelberg populations after being exposed to 200 ppm peracetic acid (PAA). Treatment with NaClO caused an average of 2.73 ± 0.23 log CFU of S. Typhimurium per coupon removed with treatment at 200 ppm while 3.36 ± 0.54 log CFU were removed at 200,000 ppm. Treatment with PAA caused an average of 2.62 ± 0.15 log CFU removed for S. Typhimurium and 1.41 ± 0.17 log CFU for S. Heidelberg (parent) and 1.61 ± 0.08 log CFU (marker). Lastly, scanning electron microscopy (SEM) was used to visualize cell attachment and coupon surface topography. SEM images showed that remaining attached cell populations were visible even after sanitizer application. Conventional plating and qPCR yielded similar levels of enumerated bacterial populations

  12. A Portable Impedance Immunosensing System for Rapid Detection of Salmonella Typhimurium.

    Science.gov (United States)

    Wen, Tao; Wang, Ronghui; Sotero, America; Li, Yanbin

    2017-08-28

    SalmonellaTyphimurium is one of the most dangerous foodborne pathogens and poses a significant threat to human health. The objective of this study was to develop a portable impedance immunosensing system for rapid and sensitive detection of S. Typhimurium in poultry. The developed portable impedance immunosensing system consisted of a gold interdigitated array microelectrode (IDAM), a signal acquisitive interface and a laptop computer with LabVIEW software. The IDAM was first functionalized with 16-Mercaptohexadecanoic acid, and streptavidin was immobilized onto the electrode surface through covalent bonding. Then, biotin-labelled S. Typhimurium-antibody was immobilized onto the IDAM surface. Samples were dropped on the surface of the IDAM and the S. Typhimurium cells in the samples were captured by the antibody on the IDAM. This resulted in impedance changes that were measured and displayed with the LabVIEW software. An equivalent circuit of the immunosensor demonstrated that the largest change in impedance was due to the electron-transfer resistance. The equivalent circuit showed an increase of 35% for the electron-transfer resistance value compared to the negative control. The calibration result indicated that the portable impedance immunosensing system could be used to measure the standard impedance elements, and it had a maximum error of measurement of approximately 13%. For pure culture detection, the system had a linear relationship between the impedance change and the logarithmic value of S. Typhimurium cells ranging from 76 to 7.6 × 10⁶ CFU (colony-forming unit) (50 μL)(-1). The immunosensor also had a correlation coefficient of 0.98, and a high specificity for detection of S. Typhimurium cells with a limit of detection (LOD) of 10² CFU (50 μL)(-1). The detection time from the moment a sample was introduced to the display of the results was 1 h. To conclude, the portable impedance immunosensing system for detection of S. Typhimurium achieved an LOD

  13. A Portable Impedance Immunosensing System for Rapid Detection of Salmonella Typhimurium

    Directory of Open Access Journals (Sweden)

    Tao Wen

    2017-08-01

    Full Text Available Salmonella Typhimurium is one of the most dangerous foodborne pathogens and poses a significant threat to human health. The objective of this study was to develop a portable impedance immunosensing system for rapid and sensitive detection of S. Typhimurium in poultry. The developed portable impedance immunosensing system consisted of a gold interdigitated array microelectrode (IDAM, a signal acquisitive interface and a laptop computer with LabVIEW software. The IDAM was first functionalized with 16-Mercaptohexadecanoic acid, and streptavidin was immobilized onto the electrode surface through covalent bonding. Then, biotin-labelled S. Typhimurium-antibody was immobilized onto the IDAM surface. Samples were dropped on the surface of the IDAM and the S. Typhimurium cells in the samples were captured by the antibody on the IDAM. This resulted in impedance changes that were measured and displayed with the LabVIEW software. An equivalent circuit of the immunosensor demonstrated that the largest change in impedance was due to the electron-transfer resistance. The equivalent circuit showed an increase of 35% for the electron-transfer resistance value compared to the negative control. The calibration result indicated that the portable impedance immunosensing system could be used to measure the standard impedance elements, and it had a maximum error of measurement of approximately 13%. For pure culture detection, the system had a linear relationship between the impedance change and the logarithmic value of S. Typhimurium cells ranging from 76 to 7.6 × 106 CFU (colony-forming unit (50 μL−1. The immunosensor also had a correlation coefficient of 0.98, and a high specificity for detection of S. Typhimurium cells with a limit of detection (LOD of 102 CFU (50 μL−1. The detection time from the moment a sample was introduced to the display of the results was 1 h. To conclude, the portable impedance immunosensing system for detection of S. Typhimurium

  14. Selection of small-colony variants of Salmonella enterica serovar typhimurium in nonphagocytic eucaryotic cells.

    Science.gov (United States)

    Cano, David A; Pucciarelli, M Graciela; Martínez-Moya, Marina; Casadesús, Josep; García-del Portillo, Francisco

    2003-07-01

    Salmonella enterica strains are enteropathogenic bacteria that survive and proliferate within vacuolar compartments of epithelial and phagocytic cells. Recently, it has been reported that fibroblast cells are capable of restricting S. enterica serovar Typhimurium intracellular growth. Here, we show that prolonged residence of bacteria in the intracellular environment of fibroblasts results in the appearance of genetically stable small-colony variants (SCV). A total of 103 SCV isolates, obtained from four independent infections, were subjected to phenotypic analysis. The following phenotypes were observed: (i) delta-aminolevulinic acid auxotrophy; (ii) requirement for acetate or succinate for growth in glucose minimal medium; (iii) auxotrophy for aromatic amino acids; and (iv) reduced growth rate under aerobic conditions not linked to nutrient auxotrophy. The exact mutations responsible for the SCV phenotype in three representative isolates were mapped in the lpd, hemL, and aroD genes, which code for dihydrolipoamide dehydrogenase, glutamate-1-semyaldehyde aminotransferase, and 3-dehydroquinate dehydratase, respectively. The lpd, hemL, and aroD mutants had intracellular persistence rates in fibroblasts that were 3 to 4 logs higher than that of the parental strain and decreased susceptibility to aminoglycoside antibiotics. All three of these SCV isolates were attenuated in the BALB/c murine typhoid model. Complementation with lpd(+), hem(+), and aroD(+) genes restored the levels of intracellular persistence and antibiotic susceptibility to levels of the wild-type strain. However, virulence was not exhibited by any of the complemented strains. Altogether, our data demonstrate that similar to what it has been reported for SCV isolates of other pathogens, S. enterica SCV display enhanced intracellular persistence in eucaryotic cells and are impaired in the ability to cause overt disease. In addition, they also suggest that S. enterica SCV may be favored in vivo.

  15. Detection of Salmonella spp, Salmonella Enteritidis and Typhimurium in naturally infected broiler chickens by a multiplex PCR-based assay

    National Research Council Canada - National Science Library

    Paião, F G; Arisitides, L G A; Murate, L S; Vilas-Bôas, G T; Vilas-Boas, L A; Shimokomaki, M

    2013-01-01

    The presence of Salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible...

  16. Persistence of a Salmonella enterica serovar typhimurium DT12 clone in a piggery and in agricultural soil amended with Salmonella-contaminated slurry

    DEFF Research Database (Denmark)

    Baloda, Suraj B.; Christensen, Lise; Trajcevska, Silvija

    2001-01-01

    ) and subclinical isolates from the same farm (collected in 1996 and later) showed identical patterns, indicating long-term persistence of the Salmonella enterica serovar Typhimurium DT12 clone in the herd environment. Furthermore, when Salmonella-contaminated slurry was disposed of on the agricultural soil (a...... common waste disposal practice), the pathogen was isolated up to 14 days after the spread, indicating potentially high risks of transmission of the pathogen in the environment, animals, and humans....

  17. Salmonella enterica Serovar Typhimurium Skills To Succeed in the Host: Virulence and Regulation

    Science.gov (United States)

    Fàbrega, Anna

    2013-01-01

    SUMMARY Salmonella enterica serovar Typhimurium is a primary enteric pathogen infecting both humans and animals. Infection begins with the ingestion of contaminated food or water so that salmonellae reach the intestinal epithelium and trigger gastrointestinal disease. In some patients the infection spreads upon invasion of the intestinal epithelium, internalization within phagocytes, and subsequent dissemination. In that case, antimicrobial therapy, based on fluoroquinolones and expanded-spectrum cephalosporins as the current drugs of choice, is indicated. To accomplish the pathogenic process, the Salmonella chromosome comprises several virulence mechanisms. The most important virulence genes are those located within the so-called Salmonella pathogenicity islands (SPIs). Thus far, five SPIs have been reported to have a major contribution to pathogenesis. Nonetheless, further virulence traits, such as the pSLT virulence plasmid, adhesins, flagella, and biofilm-related proteins, also contribute to success within the host. Several regulatory mechanisms which synchronize all these elements in order to guarantee bacterial survival have been described. These mechanisms govern the transitions from the different pathogenic stages and drive the pathogen to achieve maximal efficiency inside the host. This review focuses primarily on the virulence armamentarium of this pathogen and the extremely complicated regulatory network controlling its success. PMID:23554419

  18. Biofilm formation ability of Salmonella enterica serovar Typhimurium acrAB mutants.

    Science.gov (United States)

    Schlisselberg, Dov B; Kler, Edna; Kisluk, Guy; Shachar, Dina; Yaron, Sima

    2015-10-01

    Recent studies offer contradictory findings about the role of multidrug efflux pumps in bacterial biofilm development. Thus, the aim of this study was to investigate the involvement of the AcrAB efflux pump in biofilm formation by investigating the ability of AcrB and AcrAB null mutants of Salmonella enterica serovar Typhimurium to produce biofilms. Three models were used to compare the ability of S. Typhimurium wild-type and its mutants to form biofilms: formation of biofilm on polystyrene surfaces; production of biofilm (mat model) on the air/liquid interface; and expression of curli and cellulose on Congo red-supplemented agar plates. All three investigated genotypes formed biofilms with similar characteristics. However, upon exposure to chloramphenicol, formation of biofilms on solid surfaces as well as the production of curli were either reduced or were delayed more significantly in both mutants, whilst there was no visible effect on pellicle formation. It can be concluded that when no selective pressure is applied, S. Typhimurium is able to produce biofilms even when the AcrAB efflux pumps are inactivated, implying that the use of efflux pump inhibitors to prevent biofilm formation is not a general solution and that combined treatments might be more efficient. Other factors that affect the ability to produce biofilms depending on efflux pump activity are yet to be identified. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  19. Salmonella enterica serovar Typhimurium adhesion and cytotoxicity during epithelial cell stress is reduced by Lactobacillus rhamnosus GG

    Directory of Open Access Journals (Sweden)

    Burkholder Kristin M

    2009-07-01

    Full Text Available Abstract Background Physiological stressors may alter susceptibility of the host intestinal epithelium to infection by enteric pathogens. In the current study, cytotoxic effect, adhesion and invasion of Salmonella enterica serovar Typhimurium (S. Typhimurium to Caco-2 cells exposed to thermal stress (41°C, 1 h was investigated. Probiotic bacteria have been shown to reduce interaction of pathogens with the epithelium under non-stress conditions and may have a significant effect on epithelial viability during infection; however, probiotic effect on pathogen interaction with epithelial cells under physiological stress is not known. Therefore, we investigated the influence of Lactobacillus rhamnosus GG and Lactobacillus gasseri on Salmonella adhesion and Salmonella-induced cytotoxicity of Caco-2 cells subjected to thermal stress. Results Thermal stress increased the cytotoxic effect of both S. Typhimurium (P = 0.0001 and nonpathogenic E. coli K12 (P = 0.004 to Caco-2 cells, and resulted in greater susceptibility of cell monolayers to S. Typhimurium adhesion (P = 0.001. Thermal stress had no significant impact on inflammatory cytokines released by Caco-2 cells, although exposure to S. Typhimurium resulted in greater than 80% increase in production of IL-6 and IL-8. Blocking S. Typhimurium with anti-ShdA antibody prior to exposure of Salmonella decreased adhesion (P = 0.01 to non-stressed and thermal-stressed Caco-2 cells. Pre-exposure of Caco-2 cells to L. rhamnosus GG significantly reduced Salmonella-induced cytotoxicity (P = 0.001 and Salmonella adhesion (P = 0.001 to Caco-2 cells during thermal stress, while L. gasseri had no effect. Conclusion Results suggest that thermal stress increases susceptibility of intestinal epithelial Caco-2 cells to Salmonella adhesion, and increases the cytotoxic effect of Salmonella during infection. Use of L. rhamnosus GG as a probiotic may reduce the severity of infection during epithelial cell stress. Mechanisms

  20. Resveratrol induces membrane and DNA disruption via pro-oxidant activity against Salmonella typhimurium.

    Science.gov (United States)

    Lee, Wonjong; Lee, Dong Gun

    2017-07-22

    Resveratrol is a flavonoid found in various plants including grapes, which has been reported to be active against various pathogenic bacteria. However, antibacterial effects and mechanisms via pro-oxidant property of resveratrol remain unknown and speculative. This research investigated antibacterial mechanism of resveratrol against a food-borne human pathogen Salmonella typhimurium, and confirmed the cell death associated oxidative damage. Resveratrol increased outer membrane permeability and membrane depolarization. It also was observed DNA injury responses such as DNA fragmentation, increasing DNA contents and cell division inhibition. Intracellular ROS accumulation, GSH depletion and significant increased malondialdehyde levels were confirmed, which indicated pro-oxidant activity of resveratrol and oxidative stress. Furthermore, the observed lethal damages were reduced by antioxidant N-acetylcysteine treatment supported the view that resveratrol-induced oxidative stress stimulated S. typhimurium cell death. In conclusion, this study expands understanding on role of pro-oxidant property and insight into previously unrecognized oxygen-dependent anti-Salmonella mechanism on resveratrol. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. In-Vitro Adhesion and Invasion Properties of Salmonella Typhimurium Competing with Bacteriophage in Epithelial Cells and Chicken Macrophages

    Directory of Open Access Journals (Sweden)

    HY Lee

    2015-12-01

    Full Text Available ABSTRACT This study was designed to assess the role of bacteriophage P22 in the adhesion, invasion, intracellular survival of, and cellular immune response to Salmonella Typhimurium in intestinal epithelial INT-407 and chicken macrophage-like HD11 cells. The ability of S. Typhimurium to adhere, invade, and survive to INT-407 and HD11cells was evaluated under Salmonella infection alone (control, phage treatment followed by Salmonella infection (PS, Salmonella infection followed by phage treatment (SP, and a combination treatment with Salmonella and phage (S+P. The number of S. Typhimurium associated on INT-407 cells was reduced from 4.2 to 2.7 log cfu/cm2 by phage treatment (SP. The number of intracellular S. Typhimurium within INT-407 cells was significantly reduced to below the detection limit (0.7 log cfu/cm2 compared with the control (3.4 log cfu/cm2. S. Typhimurium remained inside HD11 cells at 49% and 17% levels in the absence and presence of phages, respectively, at 24 h post-infection (hpi. The expression levels of IFN-g, IL-10, IL-1b, IL-6, IL-8, iNOS, and IL-12 increased in HD11 cells regardless the absence and presence of phages, while those of IL-16, TLR2-1, TLR3, and TLR7 were decreased at 0 and 24 hpi. This study sheds new light on our understanding of the role of phages in Salmonella adhesion, invasion, survival, and cellular immune responses.

  2. 40 CFR 79.68 - Salmonella typhimurium reverse mutation assay.

    Science.gov (United States)

    2010-07-01

    ... mutagen means an agent which causes a base change in DNA. In a reversion assay, this change may occur at... agent which causes the addition or deletion of single or multiple base pairs in the DNA molecule... nitrated organic compounds, i.e., nitroarenes, contribute to the overall mutagenic activity of a test...

  3. The Base Excision Repair system of Salmonella enterica serovar typhimurium counteracts DNA damage by host nitric oxide.

    Directory of Open Access Journals (Sweden)

    Anthony R Richardson

    2009-05-01

    Full Text Available Intracellular pathogens must withstand nitric oxide (NO. generated by host phagocytes. Salmonella enterica serovar Typhimurium interferes with intracellular trafficking of inducible nitric oxide synthase (iNOS and possesses multiple systems to detoxify NO.. Consequently, the level of NO. stress encountered by S. Typhimurium during infection in vivo has been unknown. The Base Excision Repair (BER system recognizes and repairs damaged DNA bases including cytosine and guanine residues modified by reactive nitrogen species. Apurinic/apyrimidinic (AP sites generated by BER glycosylases require subsequent processing by AP endonucleases. S. Typhimurium xth nfo mutants lacking AP endonuclease activity exhibit increased NO. sensitivity resulting from chromosomal fragmentation at unprocessed AP sites. BER mutant strains were thus used to probe the nature and extent of nitrosative damage sustained by intracellular bacteria during infection. Here we show that an xth nfo S. Typhimurium mutant is attenuated for virulence in C3H/HeN mice, and virulence can be completely restored by the iNOS inhibitor L-NIL. Inactivation of the ung or fpg glycosylase genes partially restores virulence to xth nfo mutant S. Typhimurium, demonstrating that NO. fluxes in vivo are sufficient to modify cytosine and guanine bases, respectively. Mutants lacking ung or fpg exhibit NO.-dependent hypermutability during infection, underscoring the importance of BER in protecting Salmonella from the genotoxic effects of host NO.. These observations demonstrate that host-derived NO. damages Salmonella DNA in vivo, and the BER system is required to maintain bacterial genomic integrity.

  4. Solar disinfection (SODIS) and subsequent dark storage of Salmonella typhimurium and Shigella flexneri monitored by flow cytometry.

    Science.gov (United States)

    Bosshard, Franziska; Berney, Michael; Scheifele, Michael; Weilenmann, Hans-Ulrich; Egli, Thomas

    2009-04-01

    Pathogenic enteric bacteria are a major cause of drinking water related morbidity and mortality in developing countries. Solar disinfection (SODIS) is an effective means to fight this problem. In the present study, SODIS of two important enteric pathogens, Shigella flexneri and Salmonella typhimurium, was investigated with a variety of viability indicators including cellular ATP levels, efflux pump activity, glucose uptake ability, and polarization and integrity of the cytoplasmic membrane. The respiratory chain of enteric bacteria was identified to be a likely target of sunlight and UVA irradiation. Furthermore, during dark storage after irradiation, the physiological state of the bacterial cells continued to deteriorate even in the absence of irradiation: apparently the cells were unable to repair damage. This strongly suggests that for S. typhimurium and Sh. flexneri, a relatively small light dose is enough to irreversibly damage the cells and that storage of bottles after irradiation does not allow regrowth of inactivated bacterial cells. In addition, we show that light dose reciprocity is an important issue when using simulated sunlight. At high irradiation intensities (>700 W m(-2)) light dose reciprocity failed and resulted in an overestimation of the effect, whereas reciprocity applied well around natural sunlight intensity (<400 W m(-2)).

  5. Inactivation of internalized Salmonella Typhimurium in lettuce and green onion using ultraviolet C irradiation and chemical sanitizers.

    Science.gov (United States)

    Ge, C; Bohrerova, Z; Lee, J

    2013-05-01

    The internalized human pathogens in fresh produce are not effectively removed during conventional washing, and therefore, it may cause foodborne illness when the produce is consumed raw. Thus, effective nonthermal processes are needed to prevent this risk. Green fluorescence protein-tagged Salmonella Typhimurium was either sprayed on the surface of iceberg lettuce or injected into the bottom part (bulb) of green onions to induce bacterial internalization. The contaminated vegetables were collected after 2 days and subjected to surface disinfection. Different fluencies of UV-C radiation (75-900 mJ cm(-2)) and two fluencies of UV-C (450, 900 mJ cm(-2)) combined with chlorine and peracetic acid (PAA) were applied to the produce to examine the inactivation efficiency of internalized bacteria. A range of 1·96-2·52 log reduction in the internalized Salmonella was achieved when the lettuce was treated with higher UV-C fluency (150, 450, 900 mJ cm(-2)) or UV-C combined with chemical disinfectants. Significant reduction (1·00-1·49 log CFU g(-1)) in internalized Salmonella was observed in green onion treated with UV-C with the fluency of 150 or 900 mJ cm(-2) or UV-C-chlorine/PAA. No significant reduction was observed in either lettuce or green onion treatments when chlorine or PAA was used alone. The food quality measured with firmness was not changed during any treatments. However, a slight colour change was observed in lettuce only when UV-C was used at 900 mJ cm(-2). High fluency UV-C can significantly inactivate the internalized Salmonella in lettuce and green onion while maintaining the food quality. This research provides applicable research outcomes for developing nonthermal methods to inactivate internalized pathogens in fresh produce. © 2013 The Society for Applied Microbiology.

  6. Survival of Salmonella Typhimurium in poultry-based meat preparations during grilling, frying and baking.

    Science.gov (United States)

    Roccato, Anna; Uyttendaele, Mieke; Cibin, Veronica; Barrucci, Federica; Cappa, Veronica; Zavagnin, Paola; Longo, Alessandra; Ricci, Antonia

    2015-03-16

    The burden of food-borne diseases still represents a threat to public health; in 2012, the domestic setting accounted for 57.6% of strong-evidence EU food-borne Salmonella outbreaks. Next to cross-contamination, inadequate cooking procedure is considered as one of the most important factors contributing to food-borne illness. The few studies which have assessed the effect of domestic cooking on the presence and numbers of pathogens in different types of meat have shown that consumer-style cooking methods can allow bacteria to survive and that the probability of eating home-cooked poultry meat that still contains surviving bacteria after heating is higher than previously assumed. Thus, the main purpose of this study was to reproduce and assess the effect of several types of cooking treatments (according to label instructions and not following label instructions) on the presence and numbers of Salmonella Typhimurium DT 104 artificially inoculated in five types of poultry-based meat preparations (burgers, sausages, ready-to-cook-kebabs, quail roulades and extruded roulades) that are likely to be contaminated by Salmonella. Three contamination levels (10 cfu/g; 100 cfu/g and 1000 cfu/g) and three cooking techniques (grilling, frying and baking) were applied. Cooking treatments performed according to label instructions eliminated Salmonella Typhimurium (absence per 25g) for contamination levels of 10 and 100 cfu/g but not for contamination levels of 1000 cfu/g. After improper cooking, 26 out of 78 samples were Salmonella-positive, and 23 out of these 26 samples were artificially contaminated with bacterial loads between 100 and 1000 cfu/g. Nine out of 26 samples provided quantifiable results with a minimum level of 1.4MPN/g in kebabs (initial inoculum level: 100 cfu/g) after grilling and a maximum level of 170MPN/g recorded in sausages (initial inoculum level: 1000 cfu/g) after grilling. Kebabs were the most common Salmonella-positive meat product after cooking

  7. Contaminated Larval and Adult Lesser Mealworms, Alphitobius diaperinus (Coleoptera: Tenebrionidae)can Transmit Salmonella Typhimurium in a Broiler Flock

    Science.gov (United States)

    The ability of the lesser mealworm, Alphitobius diaperinus (Panzer), commonly known as the darkling beetle, to transmit a marker strain Salmonella Typhimurium to day-of-hatch broiler chicks was evaluated, as well as the spread to non-challenged pen mates. Day-of-hatch chicks were orally gavaged wit...

  8. Survival of Salmonella Typhimurium on soybean sprouts after treatment with gaseous chlorine dioxide and biocontrol Pseudomonas bacteria

    Science.gov (United States)

    Control of Salmonella Typhimurium on sprouts and minimally processed produce is crucial for food and consumer safety. The aim of this research was to assess natural microflora populations on soybean and evaluate the effects of gaseous chlorine dioxide (ClO2) and biocontrol Pseudomonas on the surviva...

  9. Identification of potential drug targets in Salmonella enterica sv. Typhimurium using metabolic modelling and experimental validation

    DEFF Research Database (Denmark)

    Hartman, Hassan B.; Fell, David A.; Rossell, Sergio

    2014-01-01

    Salmonella enterica sv. Typhimurium is an established model organism for Gram-negative, intracellular pathogens. Owing to the rapid spread of resistance to antibiotics among this group of pathogens, new approaches to identify suitable target proteins are required. Based on the genome sequence of ...

  10. Inactivation of Salmonella Typhimurium and quality preservation of cherry tomatoes by in-package aerosolization of antimicrobials

    Science.gov (United States)

    The purpose of the present study was to investigate the efficacy of in-package aerosolized aqueous sanitizers in reducing populations of attenuated Salmonella enterica serovar Typhimurium inoculated on tomato fruit and in maintaining fruit quality. Cherry tomatoes were inoculated with a cocktail of ...

  11. Influence of temperature fluctuations on Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in manure.

    NARCIS (Netherlands)

    Semenov, A.V.; Bruggen, van A.H.C.; Overbeek, van L.S.; Termorshuizen, A.J.; Semenov, A.M.

    2007-01-01

    The effects of four average temperatures (7, 16, 23 and 33°C) and daily oscillations with three amplitudes (0, ±4, ±7°C) on the survival of the enteropathogens Escherichia coli O157:H7 and Salmonella serovar Typhimurium were investigated in small microcosms. Manure was inoculated with a green

  12. Inactivation of Salmonella enterica serovar Typhimurium and quality maintenance of cherry tomatoes treated with gaseous essential oils

    Science.gov (United States)

    The antimicrobial activity of the essential oils (EOs) from cinnamon bark, oregano, mustard and of their major components cinnamaldehyde, carvacrol, and allyl isothiocyanate (AIT) were evaluated as a gaseous treatment to reduce Salmonella enterica serovar Typhimurium in vitro and on tomatoes. In dif...

  13. Molecular profiling: Catecholamine modulation of gene expression in Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

    Science.gov (United States)

    Investigations of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium have demonstrated that these bacterial pathogens can respond to the presence of catecholamines including norepinephrine and/or epinephrine in their environment by modulating gene expression and exhibiting various ...

  14. Functional and crystallographic characterization of Salmonella typhimurium Cu,Zn superoxide dismutase coded by the sodCI virulence gene

    NARCIS (Netherlands)

    Pesce, A; Battistoni, A; Stroppolo, ME; Polizio, F; Nardini, M; Kroll, JS; Langford, PR; O'Neill, P; Sette, M; Desideri, A; Bolognesi, M

    2000-01-01

    The functional and three-dimensional structural features of Cu,Zn superoxide dismutase coded by the Salmonella typhimurium sodCI gene, have been characterized. Measurements of the catalytic rate indicate that this enzyme is the most efficient superoxide dismutase analyzed so far, a feature that may

  15. Use of Glycerol as an Optical Clearing Agent for Enhancing Photonic Transference and Detection of Salmonella typhimurium through Porcine Skin

    Science.gov (United States)

    The objective of this study was to evaluate glycerol (GLY) and GLY + dimethyl sulfoxide (DMSO) to increase photonic detection of transformed Salmonella typhimurium (S. typh-lux) through porcine skin. Skin was placed on 96-well plates containing S. typh-lux, imaged (5 min) using a CCD camera, and the...

  16. Inactivation of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium with compounds available in households.

    Science.gov (United States)

    Yang, Hua; Kendall, Patricia A; Medeiros, Lydia; Sofos, John N

    2009-06-01

    Solutions of selected household products were tested for their effectiveness against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. Hydrogen peroxide (1.5 and 3%), vinegar (2.5 and 5% acetic acid), baking soda (11, 33, and 50% sodium bicarbonate), household bleach (0.0314, 0.0933, and 0.670% sodium hypochlorite), 5% acetic acid (prepared from glacial acetic acid), and 5% citric acid solutions were tested against the three pathogens individually (five-strain composites of each, 10(8) CFU/ml) by using a modified AOAC International suspension test at initial temperatures of 25 and 55degrees C for 1 and 10 min. All bleach solutions (pH 8.36 to 10.14) produced a >5-log reduction of all pathogens tested after 1 min at 25 degrees C, whereas all baking soda solutions (pH 7.32 to 7.55) were ineffective (5-log reduction of both Salmonella Typhimurium and E. coli O157:H7, whereas undiluted vinegar (pH 2.58) had a similar effect only against Salmonella Typhimurium. Compared with 1 min at 25 degrees C, greater reductions of L. monocytogenes (P 3% hydrogen peroxide > undiluted vinegar and 5% acetic acid > 5% citric acid > baking soda (50% sodium bicarbonate). The sensitivity of the tested pathogens to all tested household compounds followed the sequence of Salmonella Typhimurium > E. coli O157: H7 > L. monocytogenes.

  17. Inactivation of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium with Compounds Available in Households

    National Research Council Canada - National Science Library

    Yang, Hua; Kendall, Patricia A; Medeiros, Lydia; Sofos, John N

    2009-01-01

    ...:H7, and Salmonella Typhimurium. Hydrogen peroxide (1.5 and 3%), vinegar (2.5 and 5% acetic acid), baking soda (11, 33, and 50% sodium bicarbonate), household bleach (0.0314, 0.0933, and 0.670% sodium hypochlorite...

  18. [GENETIC EVALUATION OF CONTROL VARIANTS OF STRAINS SALMONELLA TYPHIMURIUM, USED IN THE TEST SALMONELLA/MICROSOME (Ames test)].

    Science.gov (United States)

    Akhaltseva, L V; Zhurkov, V S; Sychova, L P; Krivtsova, E K

    2015-01-01

    There were analyzed data of controls with solvents (DMSO and distilled water) of experiments performed in the laboratory of genetic monitoring in 2004-2014 on Salmonella typhimurium TA 100, TA 98 and TA 97 strains in the versions without and in the presence of metabolic activation. For all strains there was no revealed effect of the either solvent or system of metabolic activation on the average number of colonies of revertants in control. Generalized parameters (historical control) of the average number of colonies of revertants per plate: TA 100--number of experi- ments--317, average--118; 95% intervals of 71-165; TA 98--number of experiments--389, mean--22; 95% intervals 9-36; TA 97--the number of experiments--217, average--142; 95% intervals of 94-191.

  19. Immunogenicity and Cross-Protective Efficacy Induced by Outer Membrane Proteins from Salmonella Typhimurium Mutants with Truncated LPS in Mice

    Directory of Open Access Journals (Sweden)

    Qiong Liu

    2016-03-01

    Full Text Available Lipopolysaccharide (LPS is a major virulence factor present in the outer membrane of Salmonella enterica serovar Typhimurium (S. Typhimurium. Outer membrane proteins (OMPs from Salmonella show high immunogenicity and provide protection against Salmonella infection, and truncated LPS alters the outer membrane composition of the cell wall. In our previous study, we demonstrated that Salmonella mutants carrying truncated LPS failed to induce strong immune responses and cross-reaction to other enteric bacteria, due to their high attenuation and low colonization in the host. Therefore, we plan to investigate whether outer membrane proteins from Salmonella mutants with truncated LPS resulting from a series of nonpolar mutations, including ∆waaC12, ∆waaF15, ∆waaG42, ∆rfaH49, ∆waaI43, ∆waaJ44, ∆waaL46, ∆wbaP45 and ∆wzy-48, affect immunogenicity and provide protection against diverse Salmonella challenge. In this study, the immunogenicity and cross-protection efficiency of purified OMPs from all mutants were investigated to explore a potential OMP vaccine to protect against homologous or heterologous serotype Salmonella challenge. The results demonstrated that OMPs from three Salmonella mutants (∆waaC12, ∆waaJ44 and ∆waaL46 induced higher immune responses and provided good protection against homologous S. Typhimurium. The OMPs from these three mutants were also selected to determine the cross-protective efficacy against homologous and heterologous serotype Salmonella. Our results indicated that the mutant ∆waaC12 can elicit higher cross-reactivity and can provide good protection against S. Choleraesuis and S. Enteritidis infection and that the cross-reactivity may be ascribed to an antigen of approximately 18.4–30 kDa.

  20. Swarm motility of Salmonella enterica serovar Typhimurium is inhibited by compounds from fruit peel extracts.

    Science.gov (United States)

    Mahadwar, G; Chauhan, K R; Bhagavathy, G V; Murphy, C; Smith, A D; Bhagwat, A A

    2015-04-01

    Controlling spread of human pathogens on fresh produce is a top priority for public health reasons. Isolation of compounds from agricultural waste that would control spread of human pathogens was explored using Salmonella enterica serovar Typhimurium as a model organism. In the environment, micro-organisms migrate as a 'community' especially when they move on moist surfaces. This type of motility is characterized as swarming motility. We examined extracts from agricultural waste such as soya bean husk, peels of orange, pineapple, avocado and pomegranate for antiswarming activity. Avocado and pineapple peels showed moderate (~40%) inhibition of swarming motility while pomegranate peel extract had high antiswarming activity (~85% inhibition) and was examined in further detail. Although the pomegranate peel extract was acidic, swarm-inhibitory activity was not due to low pH and the peel extract did not inhibit growth of Salmonella. Among the key swarm motility regulatory genes, class II (fliF, fliA, fliT and fliZ) and class III (fliC and fliM) regulators were downregulated upon exposure to pomegranate peel extract. Pomegranate peels offer great potential as a bioactive repellent for pathogenic micro-organisms on moist surfaces. Controlling the spread of food-borne pathogens in moist environments is an important microbial food safety issue. Isolation of compounds from agricultural waste (such as fruit peels) that would control spread of human pathogens was explored using Salmonella enterica serovar Typhimurium as a model organism. Pomegranate peels offer great potential as a bioactive repellent for pathogenic micro-organisms. © 2014 The Society for Applied Microbiology.

  1. Complete Proteome of a Quinolone-Resistant Salmonella Typhimurium Phage Type DT104B Clinical Strain

    Directory of Open Access Journals (Sweden)

    Susana Correia

    2014-08-01

    Full Text Available Salmonellosis is one of the most common and widely distributed foodborne diseases. The emergence of Salmonella strains that are resistant to a variety of antimicrobials is a serious global public health concern. Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104 is one of these emerging epidemic multidrug resistant strains. Here we collate information from the diverse and comprehensive range of experiments on Salmonella proteomes that have been published. We then present a new study of the proteome of the quinolone-resistant Se20 strain (phage type DT104B, recovered after ciprofloxacin treatment and compared it to the proteome of reference strain SL1344. A total of 186 and 219 protein spots were recovered from Se20 and SL1344 protein extracts, respectively, after two-dimensional gel electrophoresis. The signatures of 94% of the protein spots were successfully identified through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS. Three antimicrobial resistance related proteins, whose genes were previously detected by polymerase chain reaction (PCR, were identified in the clinical strain. The presence of these proteins, dihydropteroate synthase type-2 (sul2 gene, aminoglycoside resistance protein A (strA gene and aminoglycoside 6'-N-acetyltransferase type Ib-cr4 (aac(6'-Ib-cr4 gene, was confirmed in the DT104B clinical strain. The aac(6'-Ib-cr4 gene is responsible for plasmid-mediated aminoglycoside and quinolone resistance. This is a preliminary analysis of the proteome of these two S. Typhimurium strains and further work is being developed to better understand how antimicrobial resistance is developing in this pathogen.

  2. Complete Proteome of a Quinolone-Resistant Salmonella Typhimurium Phage Type DT104B Clinical Strain

    Science.gov (United States)

    Correia, Susana; Nunes-Miranda, Júlio D.; Pinto, Luís; Santos, Hugo M.; de Toro, María; Sáenz, Yolanda; Torres, Carmen; Capelo, José Luis; Poeta, Patrícia; Igrejas, Gilberto

    2014-01-01

    Salmonellosis is one of the most common and widely distributed foodborne diseases. The emergence of Salmonella strains that are resistant to a variety of antimicrobials is a serious global public health concern. Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) is one of these emerging epidemic multidrug resistant strains. Here we collate information from the diverse and comprehensive range of experiments on Salmonella proteomes that have been published. We then present a new study of the proteome of the quinolone-resistant Se20 strain (phage type DT104B), recovered after ciprofloxacin treatment and compared it to the proteome of reference strain SL1344. A total of 186 and 219 protein spots were recovered from Se20 and SL1344 protein extracts, respectively, after two-dimensional gel electrophoresis. The signatures of 94% of the protein spots were successfully identified through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). Three antimicrobial resistance related proteins, whose genes were previously detected by polymerase chain reaction (PCR), were identified in the clinical strain. The presence of these proteins, dihydropteroate synthase type-2 (sul2 gene), aminoglycoside resistance protein A (strA gene) and aminoglycoside 6'-N-acetyltransferase type Ib-cr4 (aac(6')-Ib-cr4 gene), was confirmed in the DT104B clinical strain. The aac(6')-Ib-cr4 gene is responsible for plasmid-mediated aminoglycoside and quinolone resistance. This is a preliminary analysis of the proteome of these two S. Typhimurium strains and further work is being developed to better understand how antimicrobial resistance is developing in this pathogen. PMID:25196519

  3. Acid environments affect biofilm formation and gene expression in isolates of Salmonella enterica Typhimurium DT104.

    Science.gov (United States)

    O'Leary, Denis; McCabe, Evonne M; McCusker, Matthew P; Martins, Marta; Fanning, Séamus; Duffy, Geraldine

    2015-08-03

    The aim of this study was to examine the survival and potential virulence of biofilm-forming Salmonella Typhimurium DT104 under mild acid conditions. Salmonella Typhimurium DT104 employs an acid tolerance response (ATR) allowing it to adapt to acidic environments. The threat that these acid adapted cells pose to food safety could be enhanced if they also produce biofilms in acidic conditions. The cells were acid-adapted by culturing them in 1% glucose and their ability to form biofilms on stainless steel and on the surface of Luria Bertani (LB) broth at pH7 and pH5 was examined. Plate counts were performed to examine cell survival. RNA was isolated from cells to examine changes in the expression of genes associated with virulence, invasion, biofilm formation and global gene regulation in response to acid stress. Of the 4 isolates that were examined only one (1481) that produced a rigid biofilm in LB broth at pH7 also formed this same structure at pH5. This indicated that the lactic acid severely impeded the biofilm producing capabilities of the other isolates examined under these conditions. Isolate 1481 also had higher expression of genes associated with virulence (hilA) and invasion (invA) with a 24.34-fold and 13.68-fold increase in relative gene expression respectively at pH5 compared to pH7. Although genes associated with biofilm formation had increased expression in response to acid stress for all the isolates this only resulted in the formation of a biofilm by isolate 1481. This suggests that in addition to the range of genes associated with biofilm production at neutral pH, there are genes whose protein products specifically aid in biofilm production in acidic environments. Furthermore, it highlights the potential for the use of lactic acid for the inhibition of Salmonella biofilms. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. An incomplete TCA cycle increases survival of Salmonella Typhimurium during infection of resting and activated murine macrophages.

    Science.gov (United States)

    Bowden, Steven D; Ramachandran, Vinoy K; Knudsen, Gitte M; Hinton, Jay C D; Thompson, Arthur

    2010-11-08

    In comparison to the comprehensive analyses performed on virulence gene expression, regulation and action, the intracellular metabolism of Salmonella during infection is a relatively under-studied area. We investigated the role of the tricarboxylic acid (TCA) cycle in the intracellular replication of Salmonella Typhimurium in resting and activated macrophages, epithelial cells, and during infection of mice. We constructed deletion mutations of 5 TCA cycle genes in S. Typhimurium including gltA, mdh, sdhCDAB, sucAB, and sucCD. We found that the mutants exhibited increased net intracellular replication in resting and activated murine macrophages compared to the wild-type. In contrast, an epithelial cell infection model showed that the S. Typhimurium ΔsucCD and ΔgltA strains had reduced net intracellular replication compared to the wild-type. The glyoxylate shunt was not responsible for the net increased replication of the TCA cycle mutants within resting macrophages. We also confirmed that, in a murine infection model, the S. Typhimurium ΔsucAB and ΔsucCD strains are attenuated for virulence. Our results suggest that disruption of the TCA cycle increases the ability of S. Typhimurium to survive within resting and activated murine macrophages. In contrast, epithelial cells are non-phagocytic cells and unlike macrophages cannot mount an oxidative and nitrosative defence response against pathogens; our results show that in HeLa cells the S. Typhimurium TCA cycle mutant strains show reduced or no change in intracellular levels compared to the wild-type. The attenuation of the S. Typhimurium ΔsucAB and ΔsucCD mutants in mice, compared to their increased net intracellular replication in resting and activated macrophages suggest that Salmonella may encounter environments within the host where a complete TCA cycle is advantageous.

  5. Factores Gre de Salmonella enterica serovar Typhimurium, su papel en el control de la filosofía y patogenicidad

    OpenAIRE

    Gaviria Cantín, Tania Cristina

    2016-01-01

    [spa] El género Salmonella, está compuesto de bacterias Gram-negativas, no esporuladas, en forma de bacilo. Salmonella tiene importante relevancia a nivel de salud pública ya que es uno de los principales patógenos entéricos tanto en países desarrollados como en vías de desarrollo. En los casos de gastroenteritis notificados en España, Salmonella se posiciona en segundo lugar, después de Campylobacter. En este trabajo se utilizó como organismo modelo de estudio S. enterica serovar Typhimurium...

  6. Experimental annotation of post-translational features and translated coding regions in the pathogen Salmonella Typhimurium

    Directory of Open Access Journals (Sweden)

    Smith Richard D

    2011-08-01

    Full Text Available Abstract Background Complete and accurate genome annotation is crucial for comprehensive and systematic studies of biological systems. However, determining protein-coding genes for most new genomes is almost completely performed by inference using computational predictions with significant documented error rates (> 15%. Furthermore, gene prediction programs provide no information on biologically important post-translational processing events critical for protein function. Results We experimentally annotated the bacterial pathogen Salmonella Typhimurium 14028, using "shotgun" proteomics to accurately uncover the translational landscape and post-translational features. The data provide protein-level experimental validation for approximately half of the predicted protein-coding genes in Salmonella and suggest revisions to several genes that appear to have incorrectly assigned translational start sites, including a potential novel alternate start codon. Additionally, we uncovered 12 non-annotated genes missed by gene prediction programs, as well as evidence suggesting a role for one of these novel ORFs in Salmonella pathogenesis. We also characterized post-translational features in the Salmonella genome, including chemical modifications and proteolytic cleavages. We find that bacteria have a much larger and more complex repertoire of chemical modifications than previously thought including several novel modifications. Our in vivo proteolysis data identified more than 130 signal peptide and N-terminal methionine cleavage events critical for protein function. Conclusion This work highlights several ways in which application of proteomics data can improve the quality of genome annotations to facilitate novel biological insights and provides a comprehensive proteome map of Salmonella as a resource for systems analysis.

  7. Effects of a challenge dose of Salmonella Typhimurium or Salmonella Yoruba on the patterns of excretion and antibody responses of pigs.

    Science.gov (United States)

    Osterberg, J; Wallgren, P

    2008-05-03

    The epidemiology of a feed-associated Salmonella serotype (Salmonella Yoruba) was compared with that of a 'classical' serotype (Salmonella Typhimurium) by inoculating pigs aged 10 weeks with 0.65 x 10(3), 0.65 x 10(6) or 0.65 x 10(9) colony-forming units (cfu) of either serotype. The pigs were then monitored for eight weeks with respect to the faecal excretion of Salmonella species and the presence of serum antibodies. Only minor differences were observed between the two serotypes but the dose inoculated had significant effects. The pigs inoculated with 0.65 x 10(9) cfu shed Salmonella species in faeces constantly for four weeks, and intermittently during the subsequent four weeks; the pigs inoculated with 0.65 x 10(6) cfu shed Salmonella species intermittently for four weeks, but not for longer, and the pigs inoculated with 0.65 x 10(3) cfu generally did not excrete Salmonella species. The pigs inoculated with 0.65 x 10(9) cfu S Typhimurium seroconverted at a high titre within two weeks, the pigs inoculated with 0.65 x 10(6) cfu seroconverted later and with lower titres of antibodies, and the pigs inoculated with 0.65 x 10(3) cfu did not seroconvert. A similar pattern was observed with S Yoruba, but the responses were slower and at lower titres.

  8. Liver function and bacteriology of organs in broiler inoculated with nalidixic acid-resistant Salmonella Typhimurium and treated with organic acids

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    Tatiane M. Rocha

    2013-07-01

    Full Text Available AbAns etxrpaecritment was carried out with 630 one-day-old chicks to evaluate the effects of organic acids when birds were experimentally inoculated with Salmonella Typhimurium. Liver damage and the persistence of the bacterium in the organs were evaluated as well. Broilers were distributed in a completely randomised experimental design in a 3×2 factorial arrangement of six treatments with seven replicates of 15 birds each. Birds were inoculated with saline solution or the bacterium via gavage at 1 day of age, or were offered a feed containing or not the organic acid blend for the period of 7 to 14 days of age. A dose of 5.0x102 colony-forming units (CFU/0.5 mL of Salmonella Typhimurium was used for inoculation both via gavage and feed. The parameters evaluated are weight, liver histopathology, liver and serum biochemistry, and bacteriological analyses of the caeca, crop, spleen, and liver and heart pool. At 21 and 28 days of age, the liver of the non-inoculated groups was significantly lighter as compared to the other treatments. Birds fed organic acids presented lower bacterial isolation rates in all organs tested. Birds inoculated in the crop and treated with organic acids presented lower E. coli CFU counts (P<0.05. Birds inoculated with Salmonella presented significant changes (P<0.05 in liver enzymes, as detected by serum biochemistry, and in liver histopathology. It was concluded that organic acids effectively controlled Salmonella Typhimurium and did not cause any liver damage.

  9. Effectiveness of superheated steam for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type 30, and Listeria monocytogenes on almonds and pistachios.

    Science.gov (United States)

    Ban, Ga-Hee; Kang, Dong-Hyun

    2016-03-02

    This study was undertaken to evaluate the effectiveness of superheated steam (SHS) on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type (PT) 30 and Listeria monocytogenes on almonds and in-shell pistachios and to determine the effect of superheated steam heating on quality by measuring color and texture changes. Almonds and in-shell pistachios inoculated with four foodborne pathogens were treated with saturated steam (SS) at 100 °C and SHS at 125, 150, 175, and 200 °C for various times. Exposure of almonds and pistachios to SHS for 15 or 30s at 200 °C achieved >5l og reductions among all tested pathogens without causing significant changes in color values or texture parameters (P>0.05). For both almonds and pistachios, acid and peroxide values (PV) following SS and SHS treatment for up to 15s and 30s, respectively, were within the acceptable range (PVnuts industry by improving inactivation of foodborne pathogens on almonds and pistachios while simultaneously reducing processing time. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. A novel contribution of spvB to pathogenesis of Salmonella Typhimurium by inhibiting autophagy in host cells.

    Science.gov (United States)

    Chu, Yuanyuan; Gao, Song; Wang, Ting; Yan, Jing; Xu, Guangmei; Li, Yuanyuan; Niu, Hua; Huang, Rui; Wu, Shuyan

    2016-02-16

    Salmonella plasmid virulence genes (spv) are highly conserved in strains of clinically important Salmonella serovars. It is essential for Salmonella plasmid-correlated virulence, although the exact mechanism remains to be elucidated. Autophagy has been reported to play an important role in host immune responses limiting Salmonella infection. Our previous studies demonstrated that Salmonella conjugative plasmid harboring spv genes could enhance bacterial cytotoxicity by inhibiting autophagy. In the present study, we investigated whether spvB, which is one of the most important constituents of spv ORF could intervene in autophagy pathway. Murine macrophage-like cells J774A.1, human epithelial HeLa cells, and BALB/c mice infected with Salmonella Typhimurium wild type, mutant and complementary strains (carrying or free spvB or complemented only with ADP-ribosyltransferase activity of SpvB) were used in vitro and in vivo assay, respectively. To further explore the molecular mechanisms, both SpvB ectopic eukaryotic expression system and cells deficient in essential autophagy components by siRNA were generated. Results indicated that spvB could suppress autophagosome formation through its function in depolymerizing actin, and aggravate inflammatory injury of the host in response to S. Typhimurium infection. Our studies demonstrated virulence of spvB involving in inhibition of autophagic flux for the first time, which could provide novel insights into Salmonella pathogenesis, and have potential application to develop new antibacterial strategies for Salmonellosis.

  11. Immune effect of heat-killed multistrain of Lactobacillus acidophilus against Salmonella typhimurium invasion to mice.

    Science.gov (United States)

    Lin, W-H; Yu, B; Lin, C-K; Hwang, W-Z; Tsen, H-Y

    2007-01-01

    This study attempted to determine whether lactic acid bacteria (LAB) could have a better probiotic function when used as a multistrain mixture, i.e. Mix-LAB, than when used as a monostrain. To this end, three strains of Lactobacillus acidophilus, specifically strain LAP5, LAF1 and LAH7, were heat-killed and mixed. This heat-killed Mix-LAB was used to evaluate the effectiveness of multistrain in inhibiting Salmonella invasion into cultured cells and into organs (spleen and liver) of live mice. BALB/c mice were orally administered with heat-killed Mix-LAB or sterile normal saline (control) for seven consecutive days and then challenged with orally administered Salmonella typhimurium on day 8. Results showed that, at day 6 after the challenge, the mice which had received Mix-LAB exhibited lower rates (P 0.05) between these two groups of mice. After the challenge, however, the serum TNF-alpha level was significantly elevated (P nitric oxide release, and increased phagocytic activity in macrophages. Our findings suggest that heat-killed Mix-LAB can inhibit Salmonella invasion of mouse organs through the immunomodulating role of activated macrophage. The ability of heat-killed Mix-LAB to prevent bacterial infection in mice was found to be more significant than that of viable monostrain. This effect may be due to the activation of the immune system rather than to the adherence of LAB to the intestine epithelium.

  12. Practical considerations of surveillance of Salmonella serovars other than Enteritidis and Typhimurium.

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    Wagenaar, J A; Hendriksen, R S; Carrique-Mas, J

    2013-08-01

    Non-typhoid Salmonella serovars other than Salmonella enterica serovars S. Enteritidis (SE) and S.Typhimurium (ST) are isolated throughout the world with huge variations in prevalence. Besides the more generally occurring serovars, such as S. Infantis and S. Hadar, there are many examples of serovars that are principally reported from the regions and are most probably associated with local reservoirs. In most countries of the world, no formal surveillance systems for human salmonellosis are in place and data are limited to ad hoc studies. Data on animals, food and animal feed are even more scarce. The identification of non-SE/ST serovars may be hampered by a lack of experience in serotyping and the availability of quality-assured antisera. Subtyping Salmonella remains important to identify sources of human infections and to target interventions and control measurements. However, in the future, there will be an increasing use of culture-independent diagnostic assays, with the consequence that epidemiological subtyping and antimicrobial susceptibility data will no longer be generated. The validation of these assays for all serovars, particularly the rare ones, needs attention. Although current subtyping based on the Kauffmann-White scheme is well established, and has been shown to be robust, a new generation of subtyping methods will replace it in the near future.

  13. An outbreak of Salmonella typhimurium PTI35 gastroenteritis associated with a minimally cooked dessert containing raw eggs.

    Science.gov (United States)

    Sarna, Mohinder; Dowse, Gary; Evans, Greg; Guest, Charles

    2002-01-01

    In April 2000, we investigated an outbreak of gastroenteritis amongst attendees of a local community dinner in a Perth suburb. Of the 98 people interviewed (response rate 98%), 53 reported gastrointestinal symptoms (attack rate 54%). Faecal cultures from 11 cases, 2 food preparers, 1 waitress and leftover mock ice-cream dessert grew Salmonella Typhimurium PT135. Of the 3 food handlers, one was asymptomatic, another gave an unclear history of onset of illness and the waitress claimed illness onset 9 days after the dinner. A cohort study implicated fruit salad (RR 1.64 [95% CI: 1.05-2.58], p=0.017) and/or mock ice-cream dessert (RR 1.78 [95% CI: 0.91-3.52], p=0.045). Eggs used to make the mock ice-cream dessert were supplied directly from the producer who used inappropriate shell cleaning methods. The method of preparation of the dessert encouraged contamination. Salmonella species were not isolated in poultry faecal samples collected from the implicated egg farm. The cause of this outbreak was almost certainly the ice-cream dessert with contamination most likely resulting either from the eggs used to make the dessert or one or both of the food preparers, coupled with inadequate cooking of the dessert. Eggs used in preparing food for mass consumption should be sourced from distributors with approved cleaning procedures. Furthermore, pasteurised egg products or egg pulp should be used in the preparation of uncooked or minimally cooked dishes.

  14. The common structural architecture of Shigella flexneri and Salmonella typhimurium type three secretion needles.

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    Jean-Philippe Demers

    2013-03-01

    Full Text Available The Type Three Secretion System (T3SS, or injectisome, is a macromolecular infection machinery present in many pathogenic Gram-negative bacteria. It consists of a basal body, anchored in both bacterial membranes, and a hollow needle through which effector proteins are delivered into the target host cell. Two different architectures of the T3SS needle have been previously proposed. First, an atomic model of the Salmonella typhimurium needle was generated from solid-state NMR data. The needle subunit protein, PrgI, comprises a rigid-extended N-terminal segment and a helix-loop-helix motif with the N-terminus located on the outside face of the needle. Second, a model of the Shigella flexneri needle was generated from a high-resolution 7.7-Å cryo-electron microscopy density map. The subunit protein, MxiH, contains an N-terminal α-helix, a loop, another α-helix, a 14-residue-long β-hairpin (Q51-Q64 and a C-terminal α-helix, with the N-terminus facing inward to the lumen of the needle. In the current study, we carried out solid-state NMR measurements of wild-type Shigella flexneri needles polymerized in vitro and identified the following secondary structure elements for MxiH: a rigid-extended N-terminal segment (S2-T11, an α-helix (L12-A38, a loop (E39-P44 and a C-terminal α-helix (Q45-R83. Using immunogold labeling in vitro and in vivo on functional needles, we located the N-terminus of MxiH subunits on the exterior of the assembly, consistent with evolutionary sequence conservation patterns and mutagenesis data. We generated a homology model of Shigella flexneri needles compatible with both experimental data: the MxiH solid-state NMR chemical shifts and the state-of-the-art cryoEM density map. These results corroborate the solid-state NMR structure previously solved for Salmonella typhimurium PrgI needles and establish that Shigella flexneri and Salmonella typhimurium subunit proteins adopt a conserved structure and orientation in their

  15. Fermented Beetroot Juice as a Factor Limiting Chemical Mutations Induced by MNNG in Salmonella typhimurium TA98 and TA100 Strains

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    Elżbieta Klewicka

    2010-01-01

    Full Text Available The ability of fresh and fermented beetroot juice to limit chemical mutations has been studied using the Ames test and the strains of Salmonella typhimurium TA98 and TA100. Beetroot juice was fermented in either spontaneous or controlled fermentation, with the use of selected cultures of lactic acid bacteria, three Lactobacillus paracasei strains designated as 0916, 0920, 0923, and one Lactobacillus brevis strain 0944. N-methyl-N’-nitro-N-nitrosoguanidine (MNNG was used as a standard mutagen for the induction of His+ revertants in mutations of Salmonella typhimurium TA98 and TA100. The ability to reduce mutations was studied using the Ames test and the doses of beetroot juice of 0.5, 1.0, 2.0, 5.0 and 10.0 mL per plate. The study showed that the fermented beetroot juice (10 µL/plate reduced the level of MNNG-induced mutations by 64 % in Salmonella typhimurium TA98 and by 65 % in Salmonella typhimurium TA100. The beetroot juice obtained by spontaneous fermentation retained only 24–25 % of initial antimutagenic activity (in Salmonella strain and at the highest tested dose of the juice, i.e. 10 µL/plate. The doses of 10 µL/plate of the beetroot juice fermented by three L. paracasei cultures (0916, 0920 and 0923 decreased the intensity of mutations induced by MNNG by 61, 50 and 56 % in Salmonella typhimurium TA98 and by 65, 56 and 49 % in Salmonella typhimurium TA100, respectively. The juice (10 µL/plate fermented by L. brevis 0944 strain reduced the number of mutations by 58 % in Salmonella typhimurium TA98 and by 55 % in Salmonella typhimurium TA100. Thus, the controlled lactic acid fermentation of beetroot juice conducted by selected Lactobacillus strains maintains its antimutagenic activity.

  16. Frequency and Duration of Fecal Shedding of Salmonella Serovars Heidelberg and Typhimurium by Experimentally Infected Laying Hens Housed in Enriched Colony Cages at Different Stocking Densities.

    Science.gov (United States)

    Gast, Richard K; Guraya, Rupa; Jones, Deana R; Guard, Jean; Anderson, Kenneth E; Karcher, Darrin M

    2017-09-01

    Eggs contaminated with Salmonella Enteritidis are leading sources of human salmonellosis, but Salmonella Heidelberg and Salmonella Typhimurium are also egg-associated pathogens. The management practices and housing facilities characterizing different systems for housing commercial egg flocks can influence Salmonella persistence and transmission. Animal welfare aspects of poultry housing have been widely debated, but their food safety ramifications are not thoroughly understood. The present study assessed the effects of two different bird stocking densities on the frequency and duration of fecal shedding of strains of Salmonella Heidelberg and Salmonella Typhimurium in groups of experimentally infected laying hens housed in colony cages enriched with perching and nesting areas. In separate trials, laying hens were distributed into two groups housed in enriched colony cages at stocking densities of 648 and 973 cm(2)/bird, and a third group was housed in conventional cages at 648 cm(2)/bird. All hens were orally inoculated with doses of 10(8) colony-forming units (CFU) of either Salmonella Heidelberg or Salmonella Typhimurium. At eight weekly postinoculation intervals, samples of voided feces were collected from beneath each cage and cultured to detect Salmonella. Fecal shedding of Salmonella Heidelberg continued for 8 wk in all housing groups, but Salmonella Typhimurium shedding ceased after as little as 5 wk in enriched colony cages at low stocking density. After Salmonella Heidelberg infection, the overall frequency of positive fecal cultures for all sampling dates combined was significantly (P < 0.05) greater from either conventional cages (51.0%) or enriched colony cages (46.5%) at high stocking density than from enriched colony cages at low stocking density (33.3%). No significant differences in Salmonella Typhimurium fecal isolation were identified between housing groups. These results demonstrate that stocking density can affect intestinal colonization and

  17. Quantification of contamination of lettuce by GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Franz, Eelco; Visser, Anna A; Van Diepeningen, Anne D; Klerks, Michel M; Termorshuizen, Aad J; van Bruggen, Ariena H C

    2007-02-01

    The primary objective of this study was to determine the possibility of internalization of GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. Typhimurium) strains MAE 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (Lactuca sativa cv. Tamburo) grown in an inoculated hydroponic and soil system. The second aim was to quantify the level of contamination with the use of a proper surface sterilization method. Silver nitrate was superior in reducing the number of viable bacteria on leave surfaces compared to sodium hypochlorite and ethanol. With the hydroponic system internal colonization of lettuce only occurred at high densities with S. Typhimurium MAE 119. With the soil system E. coli O157:H7, S. Typhimurium 110 and S. Typhimurium 119 were found at considerable densities in sterilized leaf samples (respectively, 3.95, 2.57 and 2.37 log cfu/g on average) with prevalences of 0.29, 0.23 and 0.15, respectively. No statistical differences were observed between the Salmonella strains. A negative correlation was observed between shoot weight and leaf contamination. The observed presence of the pathogens in lettuce, after thorough surface sterilization, demonstrates the possible presence of human pathogens in locations were they are unlikely to be removed by the actions of consumer washing and therefore pose a serious threat when occurring in field situations.

  18. Antimicrobial effect of Thai spices against Listeria monocytogenes and Salmonella typhimurium DT104.

    Science.gov (United States)

    Thongson, Chitsiri; Davidson, P Michael; Mahakarnchanakul, Warapa; Vibulsresth, Preeya

    2005-10-01

    The objective of this study was to determine the potential antimicrobial activity of extracts and essential oils of spices from Thailand against foodborne pathogenic bacteria. The antimicrobial efficacy of ginger (Zingiber officinale), fingerroot (Boesenbergia pandurata), and turmeric (Curcuma longa) was evaluated against five strains of Listeria monocytogenes and four strains of Salmonella enterica ssp. enterica serovar Typhimurium DT104. Antimicrobial activity was investigated in microbiological media by using an agar dilution assay and enumeration over time and a model food system, apple juice, by monitoring growth over time. In the agar dilution assay, water extracts of the three spices had no effect on L. monocytogenes. Similarly, 50% ethanol extracts of ginger or turmeric had no effect. In contrast, ethanolic fingerroot extracts at 5 to 10% (vol/ vol) inhibited most L. monocytogenes strains for 24 h in the agar dilution assay. Commercial essential oils (EO) of ginger or turmeric inhibited all L. monocytogenes at pathogens in food systems.

  19. Topology and organization of the Salmonella typhimurium type III secretion needle complex components.

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    Oliver Schraidt

    2010-04-01

    Full Text Available The correct organization of single subunits of multi-protein machines in a three dimensional context is critical for their functionality. Type III secretion systems (T3SS are molecular machines with the capacity to deliver bacterial effector proteins into host cells and are fundamental for the biology of many pathogenic or symbiotic bacteria. A central component of T3SSs is the needle complex, a multiprotein structure that mediates the passage of effector proteins through the bacterial envelope. We have used cryo electron microscopy combined with bacterial genetics, site-specific labeling, mutational analysis, chemical derivatization and high-resolution mass spectrometry to generate an experimentally validated topographic map of a Salmonella typhimurium T3SS needle complex. This study provides insights into the organization of this evolutionary highly conserved nanomachinery and is the basis for further functional analysis.

  20. Distinguishable Epidemics Within Different Hosts of the Multidrug Resistant Zoonotic Pathogen Salmonella Typhimurium DT104

    Science.gov (United States)

    Mather, A.E.; Reid, S.W.J.; Maskell, D.J.; Parkhill, J.; Fookes, M.C.; Harris, S.R.; Brown, D.J.; Coia, J.E.; Mulvey, M.R.; Gilmour, M.W.; Petrovska, L.; de Pinna, E.; Kuroda, M.; Akiba, M.; Izumiya, H.; Connor, T.R.; Suchard, M.A.; Lemey, P.; Mellor, D.J.; Haydon, D.T.; Thomson, N.R.

    2014-01-01

    The global epidemic of multidrug resistant Salmonella Typhimurium DT104 provides an important example, both in terms of the agent and its resistance, of a widely disseminated zoonotic pathogen. Here, with an unprecedented national collection of isolates collected contemporaneously from humans and animals, and including a sample of internationally derived isolates, we have used whole genome sequencing to dissect the phylogenetic relationships of the bacterium and its antimicrobial resistance genes through the course of an epidemic. Contrary to current tenets supporting a single homogeneous epidemic, we demonstrate that the bacterium and its resistance genes were largely maintained within animal and human populations separately, and that there was limited transmission, in either direction. We also show considerable variation in the resistance profiles, in contrast to the largely stable bacterial core genome, further emphasizing the critical importance of integrated genotypic datasets in understanding the ecology of bacterial zoonoses and antimicrobial resistance. PMID:24030491

  1. Distinguishable epidemics of multidrug-resistant Salmonella Typhimurium DT104 in different hosts.

    Science.gov (United States)

    Mather, A E; Reid, S W J; Maskell, D J; Parkhill, J; Fookes, M C; Harris, S R; Brown, D J; Coia, J E; Mulvey, M R; Gilmour, M W; Petrovska, L; de Pinna, E; Kuroda, M; Akiba, M; Izumiya, H; Connor, T R; Suchard, M A; Lemey, P; Mellor, D J; Haydon, D T; Thomson, N R

    2013-09-27

    The global epidemic of multidrug-resistant Salmonella Typhimurium DT104 provides an important example, both in terms of the agent and its resistance, of a widely disseminated zoonotic pathogen. Here, with an unprecedented national collection of isolates collected contemporaneously from humans and animals and including a sample of internationally derived isolates, we have used whole-genome sequencing to dissect the phylogenetic associations of the bacterium and its antimicrobial resistance genes through the course of an epidemic. Contrary to current tenets supporting a single homogeneous epidemic, we demonstrate that the bacterium and its resistance genes were largely maintained within animal and human populations separately and that there was limited transmission, in either direction. We also show considerable variation in the resistance profiles, in contrast to the largely stable bacterial core genome, which emphasizes the critical importance of integrated genotypic data sets in understanding the ecology of bacterial zoonoses and antimicrobial resistance.

  2. Outbreak of food poisoning due to Salmonella typhimurium DT4 in mayonnaise.

    Science.gov (United States)

    Ortega-Benito, J M; Langridge, P

    1992-05-01

    In July 1989 a large outbreak of food poisoning (68 cases) occurred at a private club in Teddington (London Borough of Richmond-upon-Thames). Initial enquiries indicated that the peak of the outbreak occurred between 20th and 26th July. An epidemiological investigation (using self-completed questionnaires) was set up to determine the probable source of infection. Two groups among those exposed were selected: club staff (129), and cricket teams playing in a club tournament (105). Response rates were 89% and 64% respectively. Overall 50% (89) had gastrointestinal symptoms, including two hospital admissions. A highly significant association was found between illness and eating sandwiches containing mayonnaise. Microbiological investigations found Salmonella typhimurium DT4 in 36 of 68 faecal samples taken. This organism is not usually associated with food poisoning outbreaks. The probable source was identified as a flock of one of the egg suppliers.

  3. Carbon and nitrogen substrate utilization by archival Salmonella typhimurium LT2 cells

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    Edwards Kelly K

    2002-09-01

    Full Text Available Abstract Background A collection of over 20,000 Salmonella typhimurium LT2 mutants, sealed for four decades in agar stabs, is a unique resource for study of genetic and evolutionary changes. Previously, we reported extensive diversity among descendants including diversity in RpoS and catalase synthesis, diversity in genome size, protein content, and reversion from auxotrophy to prototrophy. Results Extensive and variable losses and a few gains of catabolic functions were observed by this standardized method. Thus, 95 catabolic reactions were scored in each of three plates in wells containing specific carbon and nitrogen substrates. Conclusion While the phenotype microarray did not reveal a distinct pattern of mutation among the archival isolates, the data did confirm that various isolates have used multiple strategies to survive in the archival environment. Data from the MacConkey plates verified the changes in carbohydrate metabolism observed in the Biolog™ system.

  4. Frequency and duration of fecal shedding of Salmonella serovars Heidelberg and Typhimurium by experimentally infected laying hens housed in enriched colony cages at different stocking densities

    Science.gov (United States)

    Eggs contaminated with Salmonella Enteritidis are leading sources of human salmonellosis, but S. Heidelberg and S. Typhimurium are also egg-associated pathogens. The management practices and housing facilities characterizing different systems for housing commercial egg flocks can influence Salmonell...

  5. Involvement of SPI-2-encoded SpiC in flagellum synthesis in Salmonella enterica serovar Typhimurium

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    Sugita Asami

    2009-08-01

    Full Text Available Abstract Background SpiC encoded within Salmonella pathogenicity island 2 on the Salmonella enterica serovar Typhimurium chromosome is required for survival within macrophages and systemic infection in mice. Additionally, SpiC contributes to Salmonella-induced activation of the signal transduction pathways in macrophages by affecting the expression of FliC, a component of flagella filaments. Here, we show the contribution of SpiC in flagellum synthesis. Results Quantitative RT-PCR shows that the expression levels of the class 3 fliD and motA genes that encode for the flagella cap and motor torque proteins, respectively, were lower for a spiC mutant strain than for the wild-type Salmonella. Further, this mutant had lower expression levels of the class 2 genes including the fliA gene encoding the flagellar-specific alternative sigma factor. We also found differences in flagella assembly between the wild-type strain and the spiC mutant. Many flagella filaments were observed on the bacterial surface of the wild-type strain, whereas the spiC mutant had only few flagella. The absence of spiC led to reduced expression of the FlhD protein, which functions as the master regulator in flagella gene expression, although no significant difference at the transcription level of the flhDC operon was observed between the wild-type strain and the spiC mutant. Conclusion The data show that SpiC is involved in flagella assembly by affecting the post-transcription expression of flhDC.

  6. Experimental annotation of post-translational features and translated coding regions in the pathogen Salmonella Typhimurium

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    Ansong, Charles; Tolic, Nikola; Purvine, Samuel O.; Porwollik, Steffen; Jones, Marcus B.; Yoon, Hyunjin; Payne, Samuel H.; Martin, Jessica L.; Burnet, Meagan C.; Monroe, Matthew E.; Venepally, Pratap; Smith, Richard D.; Peterson, Scott; Heffron, Fred; Mcclelland, Michael; Adkins, Joshua N.

    2011-08-25

    Complete and accurate genome annotation is crucial for comprehensive and systematic studies of biological systems. For example systems biology-oriented genome scale modeling efforts greatly benefit from accurate annotation of protein-coding genes to develop proper functioning models. However, determining protein-coding genes for most new genomes is almost completely performed by inference, using computational predictions with significant documented error rates (> 15%). Furthermore, gene prediction programs provide no information on biologically important post-translational processing events critical for protein function. With the ability to directly measure peptides arising from expressed proteins, mass spectrometry-based proteomics approaches can be used to augment and verify coding regions of a genomic sequence and importantly detect post-translational processing events. In this study we utilized “shotgun” proteomics to guide accurate primary genome annotation of the bacterial pathogen Salmonella Typhimurium 14028 to facilitate a systems-level understanding of Salmonella biology. The data provides protein-level experimental confirmation for 44% of predicted protein-coding genes, suggests revisions to 48 genes assigned incorrect translational start sites, and uncovers 13 non-annotated genes missed by gene prediction programs. We also present a comprehensive analysis of post-translational processing events in Salmonella, revealing a wide range of complex chemical modifications (70 distinct modifications) and confirming more than 130 signal peptide and N-terminal methionine cleavage events in Salmonella. This study highlights several ways in which proteomics data applied during the primary stages of annotation can improve the quality of genome annotations, especially with regards to the annotation of mature protein products.

  7. Rice hull smoke extract inactivates Salmonella Typhimurium in laboratory media and protects infected mice against mortality.

    Science.gov (United States)

    Kim, Sung Phil; Kang, Mi Young; Park, Jun Cheol; Nam, Seok Hyun; Friedman, Mendel

    2012-01-01

    A previously characterized rice hull smoke extract (RHSE) was tested for bactericidal activity against Salmonella Typhimurium using the disc-diffusion method. The minimum inhibitory concentration (MIC) value of RHSE was 0.822% (v/v). The in vivo antibacterial activity of RHSE (1.0%, v/v) was also examined in a Salmonella-infected Balb/c mouse model. Mice infected with a sublethal dose of the pathogens were administered intraperitoneally a 1.0% solution of RHSE at four 12-h intervals during the 48-h experimental period. The results showed that RHSE inhibited bacterial growth by 59.4%, 51.4%, 39.6%, and 28.3% compared to 78.7%, 64.6%, 59.2%, and 43.2% inhibition with the medicinal antibiotic vancomycin (20 mg/mL). By contrast, 4 consecutive administrations at 12-h intervals elicited the most effective antibacterial effect of 75.0% and 85.5% growth reduction of the bacteria by RHSE and vancomycin, respectively. The combination of RHSE and vancomycin acted synergistically against the pathogen. The inclusion of RHSE (1.0% v/w) as part of a standard mouse diet fed for 2 wk decreased mortality of 10 mice infected with lethal doses of the Salmonella. Photomicrographs of histological changes in liver tissues show that RHSE also protected the liver against Salmonella-induced pathological necrosis lesions. These beneficial results suggest that the RHSE has the potential to complement wood-derived smokes as antimicrobial flavor formulations for application to human foods and animal feeds. The new antimicrobial and anti-inflammatory rice hull derived liquid smoke has the potential to complement widely used wood-derived liquid smokes as an antimicrobial flavor and health-promoting formulation for application to foods. Journal of Food Science © 2011 Institute of Food Technologists® No claim to US original government works.

  8. Molecular characterization of the Na+/H+-antiporter NhaA from Salmonella Typhimurium.

    Science.gov (United States)

    Lentes, Christopher J; Mir, Syed H; Boehm, Marc; Ganea, Constanta; Fendler, Klaus; Hunte, Carola

    2014-01-01

    Na+/H+ antiporters are integral membrane proteins that are present in almost every cell and in every kingdom of life. They are essential for the regulation of intracellular pH-value, Na+-concentration and cell volume. These secondary active transporters exchange sodium ions against protons via an alternating access mechanism, which is not understood in full detail. Na+/H+ antiporters show distinct species-specific transport characteristics and regulatory properties that correlate with respective physiological functions. Here we present the characterization of the Na+/H+ antiporter NhaA from Salmonella enterica serovar Thyphimurium LT2, the causing agent of food-born human gastroenteritis and typhoid like infections. The recombinant antiporter was functional in vivo and in vitro. Expression of its gene complemented the Na+-sensitive phenotype of an E. coli strain that lacks the main Na+/H+ antiporters. Purified to homogeneity, the antiporter was a dimer in solution as accurately determined by size-exclusion chromatography combined with multi-angle laser-light scattering and refractive index monitoring. The purified antiporter was fully capable of electrogenic Na+(Li+)/H+-antiport when reconstituted in proteoliposomes and assayed by solid-supported membrane-based electrophysiological measurements. Transport activity was inhibited by 2-aminoperimidine. The recorded negative currents were in agreement with a 1Na+(Li+)/2H+ stoichiometry. Transport activity was low at pH 7 and up-regulation above this pH value was accompanied by a nearly 10-fold decrease of KmNa (16 mM at pH 8.5) supporting a competitive substrate binding mechanism. K+ does not affect Na+ affinity or transport of substrate cations, indicating that selectivity of the antiport arises from the substrate binding step. In contrast to homologous E. coli NhaA, transport activity remains high at pH values above 8.5. The antiporter from S. Typhimurium is a promising candidate for combined structural and

  9. Molecular characterization of the Na+/H+-antiporter NhaA from Salmonella Typhimurium.

    Directory of Open Access Journals (Sweden)

    Christopher J Lentes

    Full Text Available Na+/H+ antiporters are integral membrane proteins that are present in almost every cell and in every kingdom of life. They are essential for the regulation of intracellular pH-value, Na+-concentration and cell volume. These secondary active transporters exchange sodium ions against protons via an alternating access mechanism, which is not understood in full detail. Na+/H+ antiporters show distinct species-specific transport characteristics and regulatory properties that correlate with respective physiological functions. Here we present the characterization of the Na+/H+ antiporter NhaA from Salmonella enterica serovar Thyphimurium LT2, the causing agent of food-born human gastroenteritis and typhoid like infections. The recombinant antiporter was functional in vivo and in vitro. Expression of its gene complemented the Na+-sensitive phenotype of an E. coli strain that lacks the main Na+/H+ antiporters. Purified to homogeneity, the antiporter was a dimer in solution as accurately determined by size-exclusion chromatography combined with multi-angle laser-light scattering and refractive index monitoring. The purified antiporter was fully capable of electrogenic Na+(Li+/H+-antiport when reconstituted in proteoliposomes and assayed by solid-supported membrane-based electrophysiological measurements. Transport activity was inhibited by 2-aminoperimidine. The recorded negative currents were in agreement with a 1Na+(Li+/2H+ stoichiometry. Transport activity was low at pH 7 and up-regulation above this pH value was accompanied by a nearly 10-fold decrease of KmNa (16 mM at pH 8.5 supporting a competitive substrate binding mechanism. K+ does not affect Na+ affinity or transport of substrate cations, indicating that selectivity of the antiport arises from the substrate binding step. In contrast to homologous E. coli NhaA, transport activity remains high at pH values above 8.5. The antiporter from S. Typhimurium is a promising candidate for combined

  10. Transcriptomic Responses of Salmonella enterica Serovars Enteritidis and Typhimurium to Chlorine-Based Oxidative Stress▿ †

    Science.gov (United States)

    Wang, Siyun; Phillippy, Adam M.; Deng, Kaiping; Rui, Xiaoqian; Li, Zengxin; Tortorello, Mary Lou; Zhang, Wei

    2010-01-01

    Salmonella enterica serovars Enteritidis and Typhimurium are the leading causative agents of salmonellosis in the United States. S. Enteritidis is predominantly associated with contamination of shell eggs and egg products, whereas S. Typhimurium is frequently linked to tainted poultry meats, fresh produce, and recently, peanut-based products. Chlorine is an oxidative disinfectant commonly used in the food industry to sanitize the surfaces of foods and food processing facilities (e.g., shell eggs and poultry meats). However, chlorine disinfection is not always effective, as some S. enterica strains may resist and survive the disinfection process. To date, little is known about the underlying mechanisms of how S. enterica responds to chlorine-based oxidative stress. In this study, we designed a custom bigenome microarray that consists of 385,000 60-mer oligonucleotide probes and targets 4,793 unique gene features in the genomes of S. Enteritidis strain PT4 and S. Typhimurium strain LT2. We explored the transcriptomic responses of both strains to two different chlorine treatments (130 ppm of chlorine for 30 min and 390 ppm of chlorine for 10 min) in brain heart infusion broth. We identified 209 S. enterica core genes associated with Fe-S cluster assembly, cysteine biosynthesis, stress response, ribosome formation, biofilm formation, and energy metabolism that were differentially expressed (>1.5-fold; P chlorine stress. Findings from this study suggest that the oxidative-stress response may render S. enterica resistant or susceptible to certain types of environmental stresses, which in turn promotes the development of more effective hurdle interventions to reduce the risk of S. enterica contamination in the food supply. PMID:20562293

  11. Beta-Defensin-2 and Beta-Defensin-3 Reduce Intestinal Damage Caused by Salmonella typhimurium Modulating the Expression of Cytokines and Enhancing the Probiotic Activity of Enterococcus faecium

    Directory of Open Access Journals (Sweden)

    Alessandra Fusco

    2017-01-01

    Full Text Available The intestinal microbiota is a major factor in human health and disease. This microbial community includes autochthonous (permanent inhabitants and allochthonous (transient inhabitants microorganisms that contribute to maintaining the integrity of the intestinal wall, modulating responses to pathogenic noxae and representing a key factor in the maturation of the immune system. If this healthy microbiota is disrupted by antibiotics, chemotherapy, or a change in diet, intestinal colonization by pathogenic bacteria or viruses may occur, leading to disease. To manage substantial microbial exposure, epithelial surfaces of the intestinal tract produce a diverse arsenal of antimicrobial peptides (AMPs, including, of considerable importance, the β-defensins, which directly kill or inhibit the growth of microorganisms. Based on the literature data, the purpose of this work was to create a line of intestinal epithelial cells able to stably express gene encoding human β-defensin-2 (hBD-2 and human β-defensin-3 (hBD-3, in order to test their role in S. typhimurium infections and their interaction with the bacteria of the gut microbiota.

  12. Survival of Salmonella Tennessee, Salmonella Typhimurium DT104, and Enterococcus faecium in peanut paste formulations at two different levels of water activity and fat.

    Science.gov (United States)

    Kataoka, Ai; Enache, Elena; Black, D Glenn; Elliott, Philip H; Napier, Carla D; Podolak, Richard; Hayman, Melinda M

    2014-08-01

    Long-term survival of heat-stressed Salmonella Tennessee, Salmonella Typhimurium DT104, and Enterococcus faecium was evaluated in four model peanut paste formulations with a combination of two water activity (aw) levels (0.3 and 0.6) and two fat levels (47 and 56%) over 12 months at 20 ± 1°C. Prior to storage, the inoculated peanut paste formulations were heat treated at 75°C for up to 50 min to obtain an approximately 1.0-log reduction of each organism. The cell population of each organism in each formulation was monitored with tryptic soy agar plate counts, immediately after heat treatment, at 2 weeks for the first month, and then monthly for up to 1 year. The log reductions (log CFU per gram) following 12 months of storage were between 1.3 and 2.4 for Salmonella Tennessee, 1.8 and 2.8 for Salmonella Typhimurium, and 1.1 and 2.1 for E. faecium in four types of model peanut paste formulations. Enhanced survivability was observed in pastes with lower aw for all organisms, compared with those with higher aw (P survival of all organisms was not statistically significant (P > 0.05). Whereas survivability of Salmonella Tennessee and Typhimurium DT104 did not differ significantly (P > 0.05), E. faecium demonstrated higher survivability than Salmonella (P Salmonella survived in the model peanut pastes well over 12 months, which is longer than the expected shelf life for peanut butter products. The information from this study can be used to design safer food processing and food safety plans for peanut butter processing.

  13. Inactivation of Salmonella typhimurium DT 104 in UHT whole milk by high hydrostatic pressure.

    Science.gov (United States)

    Guan, Dongsheng; Chen, Haiqiang; Hoover, Dallas G

    2005-10-15

    Cell suspensions of Salmonella typhimurium DT 104 in ultra-high temperature (UHT) whole milk were exposed to high hydrostatic pressure at 350, 400, 450, 500, 550, and 600 MPa at ambient temperature (ca. 21 degrees C). Tailing was observed in all survival curves, and sigmoidal survival curves were observed at relatively high pressure (500-600 MPa). Four modeling methods (linear and nonlinear including Weibull, modified Gompertz, and log-logistic models) were fitted to these data at 500, 550, and 600 MPa. Performances of the modeling methods were compared using mean square error (MSE). The linear regression model at these three pressure levels had a mean square error (MSE) of 1.260-2.263. Nonlinear regressions using Weibull, modified Gompertz, and log-logistic models had MSE values in the range of 0.334-0.764, 0.601-1.479, and 0.359-0.523, respectively. Modeling results indicated that first-order kinetics could not accurately describe pressure inactivation of S. typhimurium DT 104 in UHT milk; the log-logistic model produced the best fit to data.

  14. Silver Nanoparticles Against Salmonella enterica Serotype Typhimurium: Role of Inner Membrane Dysfunction.

    Science.gov (United States)

    Seong, Minju; Lee, Dong Gun

    2017-06-01

    The evolution of antibiotics-resistant bacteria is considered a major concern. To explore promising antibacterial materials and clarify their unknown mechanisms, the mode of action of silver nanoparticles (AgNPs) against Salmonella enterica serotype typhimurium was investigated. We investigated the effect of AgNPs on the bacterial membrane. The N-phenyl-1-naphthylamine assay showed that the permeability of the outer membrane was not changed by treatment with AgNPs. The O-nitrophenyl-β-D-galactopyranoside assay showed that the inner membrane permeability increased as AgNPs concentration increased. Our results showed that AgNPs affected the inner membrane without outer membrane damage. Generally, antibiotic-induced reactive oxygen species (ROS) and changes in the Ca 2+ gradient are known to contribute to bacterial cell death. Likewise, we detected that AgNPs induced the accumulation of ROS and intracellular Ca 2+ depending on its concentration, using 2',7'-dichlorodihydrofluorescein and Fura-2AM, respectively. At higher concentrations, no relationship between oxidative stress and bactericidal effects of AgNPs was confirmed through a cell viability assay and intracellular Ca 2+ assay with antioxidant N-acetylcysteine. In this study, the inner membrane disruption followed by membrane dysfunction played a key role in the antibacterial activity of AgNPs against S. typhimurium. Contrary to the expected results, ROS do not influence growth inhibition of AgNPs.

  15. Probiotics association in the suckling and nursery in piglets challenged with Salmonella typhimurium

    Directory of Open Access Journals (Sweden)

    Esther Ramalho Afonso

    2013-04-01

    Full Text Available This work aimed to study the probiotics association in 144 piglets from birth to 62 days old. In lactation, the design was completely randomized with two treatments, CTL, 1 mL of distilled water and ProbA, 5g in 15 ml of distilled water, both orally, and in the nursery in randomized block design, with 2x3 factorial arrangement of treatments, ProbA ProbB: 30g/ton of ProbB in the ration; CTL ProbB: 30g/ton of ProbB in the ration; ProbA ProbA, CTL CTL; ProbA CHA (challenged; CTL CHA. At 35 days of age the animal of the nursery were inoculated with Salmonella typhimurium orally. There was no effect of the parameters evaluated during the maternity. In nursery, the feed conversion was favorable to the ProbA. In the evaluation of fecal score, the challenged group had more diarrhea and increased elimination of S. typhimurium. Results showed the positive action of probiotics when applied at birth by the direct influence on the formation of the intestinal microbiota.

  16. Cinnamaldehyde induces changes in the protein profile of Salmonella Typhimurium biofilm.

    Science.gov (United States)

    Silva, Alex Fiori; Dos Santos, Adriele Rodrigues; Coelho Trevisan, Daliah Alves; Ribeiro, Alessandra Braga; Zanetti Campanerut-Sá, Paula Aline; Kukolj, Caroline; de Souza, Emanuel Maltempi; Cardoso, Rosilene Fressatti; Estivalet Svidzinski, Terezinha Inez; de Abreu Filho, Benicio Alves; Junior, Miguel Machinski; Graton Mikcha, Jane Martha

    2017-09-30

    The effect of cinnamaldehyde against biofilm cells of Salmonella Typhimurium ATCC 14028 was evaluated. We also assessed differential protein patterns that were expressed by biofilms compared with planktonic cells and protein expression by cinnamaldehyde-treated biofilms cells. This compound decreased biofilm biomass and metabolic activity of biofilms at both concentrations tested. Cinnamaldehyde treatment reduced the number of attached cells in polypropylene, reflected by colony count and scanning electron microscopy. The proteomic analysis of biofilms compared with planktonic cells indicated that several proteins were upregulated or downregulated, especially proteins that are involved in energy metabolism. Peroxiredoxin, ATP synthase alpha chain protein, conjugal transfer nickase/helicase TraI and elongation factor G were upregulated in untreated-biofilm cells, and their expression decreased as a function of cinnamaldehyde treatment. Cinnamaldehyde had antibiofilm activity, and several differentially expressed proteins identified provide potential and interesting targets to explore new control strategies for S. Typhimurium biofilms. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  17. The effects of stainless steel finish on Salmonella Typhimurium attachment, biofilm formation and sensitivity to chlorine.

    Science.gov (United States)

    Schlisselberg, Dov B; Yaron, Sima

    2013-08-01

    Bacterial colonization and biofilm formation on stainless steel (SS) surfaces can be sources for cross contamination in food processing facilities, possessing a great threat to public health and food quality. Here the aim was to demonstrate the influence of surface finish of AISI 316 SS on colonization, biofilm formation and susceptibility of Salmonella Typhimurium to disinfection. Initial attachment of S. Typhimurium on surfaces of SS was four times lower, when surface was polished by Bright-Alum (BA) or Electropolishing (EP), as compared to Mechanical Sanded (MS) or the untreated surface (NT). The correlation between roughness and initial bacterial attachment couldn't account on its own to explain differences seen. Biofilms with similar thickness (15-18 μm) were developed on all surfaces 1-day post inoculation, whereas EP was the least covered surface (23%). Following 5-days, biofilm thickness was lowest on EP and MS (30 μm) and highest on NT (62 μm) surfaces. An analysis of surface composition suggested a link between surface chemistry and biofilm development, where the higher concentrations of metal ions in EP and MS surfaces correlated with limited biofilm formation. Interestingly, disinfection of biofilms with chlorine was up to 130 times more effective on the EP surface (0.005% surviving) than on the other surfaces. Overall these results suggest that surface finish should be considered carefully in a food processing plant. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Comprehensive identification of Salmonella enterica serovar typhimurium genes required for infection of BALB/c mice.

    Directory of Open Access Journals (Sweden)

    Roy R Chaudhuri

    2009-07-01

    Full Text Available Genes required for infection of mice by Salmonella Typhimurium can be identified by the interrogation of random transposon mutant libraries for mutants that cannot survive in vivo. Inactivation of such genes produces attenuated S. Typhimurium strains that have potential for use as live attenuated vaccines. A quantitative screen, Transposon Mediated Differential Hybridisation (TMDH, has been developed that identifies those members of a large library of transposon mutants that are attenuated. TMDH employs custom transposons with outward-facing T7 and SP6 promoters. Fluorescently-labelled transcripts from the promoters are hybridised to whole-genome tiling microarrays, to allow the position of the transposon insertions to be determined. Comparison of microarray data from the mutant library grown in vitro (input with equivalent data produced after passage of the library through mice (output enables an attenuation score to be determined for each transposon mutant. These scores are significantly correlated with bacterial counts obtained during infection of mice using mutants with individual defined deletions of the same genes. Defined deletion mutants of several novel targets identified in the TMDH screen are effective live vaccines.

  19. Complex regulatory network encompassing the Csr, c-di-GMP and motility systems of Salmonella Typhimurium.

    Science.gov (United States)

    Jonas, Kristina; Edwards, Adrianne N; Ahmad, Irfan; Romeo, Tony; Römling, Ute; Melefors, Ojar

    2010-02-01

    Bacterial survival depends on the ability to switch between sessile and motile lifestyles in response to changing environmental conditions. In many species, this switch is governed by (3'-5')-cyclic-diguanosine monophosphate (c-di-GMP), a signalling molecule, which is metabolized by proteins containing GGDEF and/or EAL domains. Salmonella Typhimurium contains 20 such proteins. Here, we show that the RNA-binding protein CsrA regulates the expression of eight genes encoding GGDEF, GGDEF-EAL and EAL domain proteins. CsrA bound directly to the mRNA leaders of five of these genes, suggesting that it may regulate these genes post-transcriptionally. The c-di-GMP-specific phosphodiesterase STM3611, which reciprocally controls flagella function and production of biofilm matrix components, was regulated by CsrA binding to the mRNA, but was also indirectly regulated by CsrA through the FlhDC/FliA flagella cascade and STM1344. STM1344 is an unconventional (c-di-GMP-inactive) EAL domain protein, recently identified as a negative regulator of flagella gene expression. Here, we demonstrate that CsrA directly downregulates expression of STM1344, which in turn regulates STM3611 through fliA and thus reciprocally controls motility and biofilm factors. Altogether, our data reveal that the concerted and complex regulation of several genes encoding GGDEF/EAL domain proteins allows CsrA to control the motility-sessility switch in S. Typhimurium at multiple levels.

  20. [Survival of Salmonella typhimurium in the solid fraction from a farm waste water treatment plant].

    Science.gov (United States)

    Plachá, I; Venglovský, J; Lasanda, V; Plachý, P

    1997-05-01

    Survival of Salmonella typhimurium pathogens was followed in the slurry solid fraction from a pig farm waste water treatment plant. The tested S. typhimurium pathogens have survived for 117 days. The solid fraction was kept in the laboratory at 20-23 degrees C. Indicatory microorganisms at the beginning of the experiment numbered 10(8)-10(9) CFU in 1 ml sample. This number decreased by 4-5 series throughout the experiment, except for faecal coliform bacteria, which were not detected after 43 days of cultivation. Enterobacteria showed a decreasing tendency until day 83, however, on the final sampling (day 117) their count was almost double. Of physico-chemical parameters, pH showed the most striking variations. Its initial value of 6.9 increased to 8.1 at day 30, then decreased to 7.2 at day 43, and increased to 7.7 at the end of the experiment. Ammoniacal nitrogen in solid fraction was almost twice as high as the initial level. Other physico-chemical parameters were not changed significantly throughout the experiment. On the results of this experiment, decimal reduction times T90 were determined for indicatory microorganisms during the storage of solid fraction under constant conditions: psychrophilic bacteria 31.25; mesophilic bacteria 38.12; coliform bacteria 27.49; faecal streptococci 24.57 and enterobacteria 30.46 days. These data suggest a relatively long time of survival for indicatory microorganisms in the solid fraction from agricultural waste water treatment plants.

  1. Competitive Survival of Escherichia coli, Vibrio cholerae, Salmonella typhimurium and Shigella dysenteriae in Riverbed Sediments.

    Science.gov (United States)

    Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Momba, Maggy Ndombo Benteke

    2016-11-01

    Studies on the survival of bacterial enteric pathogens in riverbed sediments have mostly focused on individual organisms. Reports on the competitive survival of these pathogens in riverbed sediments under the same experimental setup are limited. We investigated the survival of Escherichia coli, Salmonella enterica ser. Typhimurium, Vibrio cholerae and Shigella dysenteriae in riverbed sediments of the Apies River. Experiments were performed in flow chambers containing three sediment types and connected to aquarium pumps immersed in river water to maintain continuous water circulation. Each chamber was inoculated with ~10 7  CFU/mL (final concentration) of each microorganism and kept at 4, 20 and 30 °C. Chambers were sampled on days 0, 1, 2, 7, 14 and 28. At 4 °C, only E. coli and S. typhimurium survived throughout the 28 experimental days. V. cholerae had the shortest survival time at this temperature and was not detected in any of the sediment chambers 24 h after inoculation. S. dysenteriae only survived until day 7. At an increased temperature of 20 °C, only S. dysenteriae was not detected on day 28 of the experiment. At 30 °C, V. cholerae and Salmonella survived longer (28 days) than E. coli (14 days) and S. dysenteriae (4 days). Vibrio cholerae was shown to have the highest T 90 values (32 days) in all sediment types at 20 and 30 °C. We conclude that the sediments of the Apies River present a favourable environment for the survival of indicator and pathogenic bacteria depending on the prevailing temperature.

  2. Protective Effect of Moderate Exercise for BALB/c Mice with Salmonella Typhimurium Infection.

    Science.gov (United States)

    Campos-Rodríguez, R; Godínez-Victoria, M; Arciniega-Martínez, I M; Reséndiz-Albor, A A; Reyna-Garfias, H; Cruz-Hernández, T R; Drago-Serrano, M E

    2016-01-01

    Moderate exercise enhances resistance to pathogen-associated infections. However, its influence on intestinal IgA levels and resistance to Salmonella typhimurium in mice has not been reported. The aim of this study was to assess the impact of moderate exercise on bacterial resistance and the intestinal-IgA response in a murine typhoid model. Sedentary and exercised (under a protocol of moderate swimming) BALB/c mice were orally infected with Salmonella typhimurium and sacrificed on days 7 or 14 post-infection (n=5 per group). Compared with infected sedentary mice, infected exercised animals had i) lower intestinal and systemic bacterial loads; ii) higher total and specific intestinal-IgA levels, iii) a higher percentage of IgA plasma cells in lamina propria; iv) a higher level on day 7 and lower level on day 14 of intestinal α- and J-chain mRNA and plasma corticosterone, v) unchanged mRNA expression of intestinal pIgR, and vi) a higher mRNA expression of liver pIgR, α-chain and J-chain on day 7. Hence, it is likely that an increase in corticosterone levels (stress response) induced by moderate exercise increased intestinal IgA levels by enabling greater liver expression of pIgR mRNA, leading to a rise in IgA transcytosis from the liver to intestine. The overall effect of these changes is an enhanced resistance to infection. © Georg Thieme Verlag KG Stuttgart · New York.

  3. A critical appraisal of the phene-plate biochemical fingerprinting system for epidemiological subtyping of Salmonella typhimurium

    DEFF Research Database (Denmark)

    On, S.L.W.; Baggesen, Dorte Lau

    1996-01-01

    The efficacy and reproducibility of the Phene-Plate (PhP) system (Biosys Inova, Stockholm, Sweden) for biochemical fingerprinting of Salmonella typhimurium was investigated. Duplicate and replicate assays on 40 epidemiologically related and unrelated strains were performed in two batches of PhP-48......P-types which are epidemiologically unjustified, (ii) tests currently recommended for PhP-typing S. typhimurium may be somewhat unstable and not satisfactory for fingerprinting purposes, (iii) caution must be exercised when comparing data from different batches of PhP-48 plates, and (iv) best results...

  4. The apeE Gene of Salmonella typhimurium Encodes an Outer Membrane Esterase Not Present in Escherichia coli

    OpenAIRE

    Carinato, Maria E.; Collin-Osdoby, Patricia; Yang, Xioming; Knox, Tina M.; Conlin, Christopher A.; Miller, Charles G.

    1998-01-01

    Salmonella typhimurium apeR mutations lead to overproduction of an outer membrane-associated N-acetyl phenylalanine β-naphthyl ester-cleaving esterase that is encoded by the apeE gene (P. Collin-Osdoby and C. G. Miller, Mol. Gen. Genet. 243:674–680, 1994). This paper reports the cloning and nucleotide sequencing of the S. typhimurium apeE gene as well as some properties of the esterase that it encodes. The predicted product of apeE is a 69.9-kDa protein which is processed to a 67-kDa species ...

  5. Impact of relative humidity, inoculum carrier and size, and native microbiota on Salmonella ser. Typhimurium survival in baby lettuce.

    Science.gov (United States)

    López-Gálvez, Francisco; Gil, Maria Isabel; Allende, Ana

    2018-04-01

    The effects of relative humidity (RH), fluctuating climate conditions, inoculum size and carrier on the survival of Salmonella enterica serovar Typhimurium on baby lettuce in environmental test chambers were studied. Buffered peptone water (BPW), distilled water (DW), and irrigation water (IW) were compared as inoculum carriers. Additionally, survival of Salmonella in suspensions prepared using filtered and unfiltered IW was assessed. Salmonella Typhimurium survived better on baby lettuce plants at high RH independently of the inoculum size. When lettuce plants were grown under fluctuating environmental conditions, Salmonella survival was similar under both RH conditions. Regarding the inoculum carrier, the inoculated microorganism survived better on lettuce plants when BPW was used as carrier both at high and low RH. Survival rate of Salmonella in IW was affected by the presence of native microbiota. Native microbiota present in IW did not affect survival of Salmonella or the levels of mesophilic bacteria on the baby lettuce leaves. The information obtained in the present study contributes to the knowledge on the effect of environmental conditions on pathogenic bacteria survival on growing edible plants. These results are useful when selecting the methodology to carry out experimental studies on the survival of microbial pathogens under different pre-harvest conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Influence of antibiotic-supplemented feed on occurrence and persistence of Salmonella typhimurium in experimentally infected swine.

    Science.gov (United States)

    Gutzmann, F; Layton, H; Simkins, K; Jarolmen, H

    1976-06-01

    The effect of chlortetracycline given at a concentration of 220.5 g/metric ton of feed and of a combination product which supplies chlortetracycline (110.2 g/metric ton), sulfamethazine (110.2 g/metric ton), and penicilin G (55.1 g/metric ton) on the occurrence and persistence of Salmonella typhimurium in experimentally infected swine was studied. Weanling pigs (av weight, 8.2 kg) were inoculated via the feed with 10(11) colony-forming units of S typhimurium 298-1NA. An equal number of nonexposed swine given identical treatment were used as controls. Infected pigs had increased temperatures (maximal av, 41 C) for the first 4 days after infection and severe diarrhea during the first 21 days. The use of chlortetracycline and a combination product at subtherapeutic concentrations in feed did not increase the Salmonella pool or prolong the carrier state in swine. A decrease in number of Salmonella shed from swine given chlortetracycline at the concentration of 220.5 g/metric ton was observed. Significant differences did not occur in Salmonella-related deaths or in emergence of multiple antibiotic-resistant Salmonella by antibiotic selection or R factor transfer. Zoonotic transmission of the infecting Salmonella to animal caretakers was not detected.

  7. Genomic relationships between selected phage types of Salmonella enterica subsp. enterica serotype typhimurium defined by ribotyping, IS200 typing and PFGE

    DEFF Research Database (Denmark)

    Olsen, J. E.; Skov, M. N.; Angen, Øystein

    1997-01-01

    The genomic relationship between isolates representing 17 definitive phage types (DTs) of Salmonella enterica subsp. enterica serotype typhimurium (S. typhimurium) were analysed using three different typing methods: IS200 typing using the restriction enzymes EcoRI and Pvull, ribotyping using Smal...

  8. Phenotypic and genotypic resistance profile of Salmonella Typhimurium to antimicrobials commonly used in poultry

    Directory of Open Access Journals (Sweden)

    CP Biffi

    2014-06-01

    Full Text Available Isolates of Salmonella sp (104 from poultry samples were isolated and serotyped where eleven were identified as Salmonella Typhimurium (ST. ST isolates were phenotypically tested by disk diffusion and minimum inhibitory concentration (MIC. Four genes related to enrofloxacin (GyrA, GyrB, ParC and ParE, two to gentamicin (AadA and AadB and two to ceftiofur (BlaCMY-2 and AmpC resistance were searched by PCR. Our results showed ST resistance to all three antibiotics tested (18.1% for ceftiofur, 45.4% for gentamicin, and 18.1% for enrofloxacin according to the diffusion test. In the MIC test, the ST isolates showed higher levels of resistance (27.2% for ceftiofur, 54.5% for gentamicin, and 18.2% for enrofloxacin. Three resistance genes out of four searched genes for enrofloxacin were found in the ST isolates. Regarding gentamicin and ceftiofur, resistance genes were found mainly in samples with resistant phenotypic profile. Interestingly, some phenotypically-resistant strains did not present the resistance gene, which suggests an alternative route of resistance. Also, sensitive strains had the presence of the gene. It is possible to conclude that the ST isolates evaluated in this study have a multidrug resistance profile to the antibiotics routinely used in poultry production, and potential of greater levels of resistance in the near future.

  9. Cloning and sequencing of hfq (host factor required for synthesis of bacteriophage Q beta RNA gene of Salmonella Typhimurium isolated from poultry

    Directory of Open Access Journals (Sweden)

    Parthasarathi Behera

    2015-05-01

    Full Text Available Aim: The aim was to clone and sequence hfq gene of Salmonella Typhimurium strain PM-45 and compare its sequence with hfq gene of other serovar of Salmonella. Materials and Methods: Salmonella Typhimurium strain PM-45 was procured from the G. B. Pant University of Agriculture and Technology, Pantnagar, India. The genomic DNA was isolated from Salmonella Typhimurium. Hfq gene was polymerase chain reaction (PCR amplified from the DNA using specific primers, which was subsequently cloned into pET32a vector and transformed into Escherichia coli BL21 pLys cells. The recombinant plasmid was isolated and subjected to restriction enzyme digestion as well as PCR. The clone was then sequenced. The sequence was analyzed and submitted in GenBank. Results: PCR produced an amplicon of 309 bp. Restriction digestion of the recombinant plasmid released the desired insert. The hfq sequence shows 100% homology with similar sequences from other Salmonella Typhimurium isolates. Both nucleotide and amino acid sequences are highly conserved. The submitted sequence is having Genbank accession no KM998764. Conclusion: Hfq, the hexameric RNA binding protein is one of the most important post-transcriptional regulator of bacteria. The sequence of hfq gene of Salmonella Typhimurium is highly conserved within and between Salmonella enterica serovars. This gene sequence is probably under heavy selection pressure to maintain the conformational integrity of its product in spite of its being not a survival gene.

  10. Transfer of primed CD4+OX40- T lymphocytes induces increased immunity to experimental Salmonella typhimurium infections in rats

    DEFF Research Database (Denmark)

    Thygesen, P; Christensen, H B; Hougen, H P

    1997-01-01

    The protective effect of primed CD4 T cells against a lethal dose of Salmonella typhimurium was studied in Lewis rats. Primed CD4 T cells were obtained by inoculating Lewis rats with a non-lethal dose of S. typhimurium. Four weeks after the infection, spleen non-adherent mononuclear cells were......4+ T cells sorted into OX40- or OX40- subpopulations significantly increased animal survival compared to controls. Animals receiving OX40+CD4+ T cells did not differ significantly in survival probability from those receiving unsorted CD+ T cells. However, animals receiving OX40-CD4+ T cells had...... a significantly better survival compared to animals given unsorted CD4+ T cells. It is concluded that OX40-CD4+ T cells can induce significant protection against S. typhimurium infections in rats. This is most likely due to the fact that the OX40-CD4+ T-cell population contains a significant number of antigen...

  11. Analysis of the contribution of bacteriophage ST64B to in vitro virulence traits of Salmonella enterica serovar Typhimurium

    DEFF Research Database (Denmark)

    Fresno, Ana Herrero; Leekitcharoenphon, Pimlapas; Hendriksen, Rene S.

    2014-01-01

    Comparison of the publicly available genomes of the virulent Salmonella enterica serovar Typhimurium (S. Typhimurium) strains SL1344, 14028s and D23580 to that of the virulence-attenuated isolate LT2 revealed the absence of a full sequence of bacteriophage ST64B in the latter. Four selected ST64B...... in in vitro assays used to predict virulence association. No difference in invasion of the Int407 human cell line was observed between the wild-type and mutated strains, but the isolate carrying the whole ST64B prophage was found to have a slightly better survival in blood. The study showed a high prevalence...... and a strong association between the prophage ST64B and isolates of S. Typhimurium collected from blood, and may indicate that such strains constitute a selected subpopulation within this serovar. Further studies are indicated to determine whether the slight increase in blood survival observed in the strain...

  12. Effects of irradiation and fumaric acid treatment on the inactivation of Listeria monocytogenes and Salmonella typhimurium inoculated on sliced ham

    Science.gov (United States)

    Song, Hyeon-Jeong; Lee, Ji-Hye; Song, Kyung Bin

    2011-11-01

    To examine the effects of fumaric acid and electron beam irradiation on the inactivation of foodborne pathogens in ready-to-eat meat products, sliced ham was inoculated with Listeria monocytogenes and Salmonella typhimurium. The inoculated ham slices were treated with 0.5% fumaric acid or electron beam irradiation at 2 kGy. Fumaric acid treatment reduced the populations of L. monocytogenes and S. typhimurium by approximately 1 log CFU/g compared to control populations. In contrast, electron beam irradiation decreased the populations of S. typhimurium and L. monocytogenes by 3.78 and 2.42 log CFU/g, respectively. These results suggest that electron beam irradiation is a better and appropriate technique for improving the microbial safety of sliced ham.

  13. A new chloramphenicol and florfenicol resistance gene flanked by two integron structures in Salmonella typhimurium DT104.

    Science.gov (United States)

    Arcangioli, M A; Leroy-Sétrin, S; Martel, J L; Chaslus-Dancla, E

    1999-05-15

    A new chloramphenicol resistance gene from Salmonella typhimurium DT104, designated floR, also conferring resistance to florfenicol, was characterized. Sequence analysis of the deduced FloR protein suggested that it belongs to the 12-TMS (transmembrane segments) multidrug efflux pumps family. The floR gene, and the downstream sequenced tetR and tetA tetracycline resistance genes, were surrounded by two class 1 integrons. The first one contained the resistance gene aadA2 and a deleted sulI resistance gene. The second one contained the beta-lactamase gene pse1 and a complete sulI gene. Thus, the floR gene is included in a multiresistance locus of at least 12.5 kb. Its particular organization and chromosomal location could be involved in the antibioresistance pattern stability of the DT104 Salmonella typhimurium strains.

  14. Transmission routes of Salmonella Typhimurium DT 104 between 14 cattle and pig herds in Denmark demonstrated by molecular fingerprinting

    DEFF Research Database (Denmark)

    Langvad, B.; Skov, M.N.; Rattenborg, E.

    2006-01-01

    and pig herds located in a geographically narrow area in Denmark was investigated. Epidemiological information and disease history of the herds was obtained through interviews. Based on this, the hypothesis for horizontal spread was proposed, and these were confirmed by comparison of the pulsed field gel...... and Impact of the Study: Salmonella Typhimurium DT 104 infected herd might pose a significant risk to herds located within the same geographic area. In advising on how to avoid the spread of this bacterium, factors like person contacts, sharing of equipment and contaminated slurry should be focussed......Aims: Salmonella Typhimurium DT 104 is generally assumed to be spread by contact between live animals, e.g. by trading. The aim of the present study was to assess the importance of other routes of transmission in the dissemination of this bacterium. Methods and Results: An outbreak among 14 cattle...

  15. Grapefruit juice and its constituents augment the effect of low pH on inhibition of survival and adherence to intestinal epithelial cells of Salmonella enterica serovar Typhimurium PT193.

    Science.gov (United States)

    Yin, Xianhua; Gyles, Carlton L; Gong, Joshua

    2012-09-03

    The present study examined the survival of Salmonella Typhimurium and its adherence to intestinal epithelial cells following inoculation into grapefruit juice and apple cider. Both liquids significantly inactivated S. Typhimurium (0.8-2.2 log reduction compared to the control); surviving Salmonella in grapefruit juice was 1.0-1.4 log lower than in apple cider at 24h incubation. Grapefruit juice contains the antimicrobial substances naringin (NAR) and naringenin (NGE); however, the effect of grapefruit juice on growth and adherence of S. Typhimurium appeared not to be related to NAR. NGE at 100-200 μg/mL reduced the adherence of Salmonella to epithelial cells by 57% and 73% compared to the control (TSB at pH 7.4) after 24 h treatment, but stimulated rather than inhibited growth of Salmonella. However, when NGE at 200 μg/mL was added to TSB at pH 3.5 Salmonella survival and adherence to intestinal epithelial cells were reduced by 2.5 log and 79%, respectively, compared to the control (TSB at pH 3.5). Addition of NGE to apple cider also caused a slight reduction in the survival of S. Typhimurium, but did not enhance the inhibitory effect on adherence due to apple cider. These data showed that low pH augmented the inhibitory effect of NGE on growth and adherence of Salmonella to intestinal epithelial cells, but the mechanism of the observed augmentative effect is not clear. Understanding the mechanism of the interaction between low pH and NGE and its inhibitory effect on growth and adherence of enteric pathogens may lead to the development of new antibacterial agents. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  16. Reduction of Salmonella enterica serovar typhimurium DT104 infection in experimentally challenged weaned pigs fed a lactobacillus-fermented feed.

    Science.gov (United States)

    Yin, Fugui; Farzan, Abdolvahab; Wang, Qi Chuck; Yu, Hai; Yin, Yulong; Hou, Yongqing; Friendship, Robert; Gong, Joshua

    2014-08-01

    Salmonella Typhimurium is a foodborne pathogen and commonly present on pig farms. Probiotics have shown potential as a means of reducing Salmonella shedding in pigs. Three experimental challenge trials were conducted to investigate the potential application of newly isolated Lactobacillus isolates for controlling Salmonella infection in pigs. In each trial, 16 Yorkshire piglets (28-d old) were randomly allocated to 1 of 4 dietary treatments: (1) basal diet (BD), (2) naturally fermented (NF) feed, (3) Lactobacillus zeae-fermented (LZ-F) feed, and 4) Lactobacillus casei-fermented (LC-F) feed. All pigs consumed their assigned diets for 3 d prior to the challenge of Salmonella Typhimurium DT104 (approximately 6 log colony-forming units/pig) through gavage. Pediococcus pentosaceus, L. zeae, and L. casei were most abundant in NF, LZ-F, and LC-F feed, respectively. After the challenge, pigs on fermented feed had lower rectal temperature, diarrhea scores, serum haptoglobin concentrations, and intestinal Salmonella counts than the control group (BD) (p ≤ 0.01). Salmonella spp. were detected in both ileocecal lymph nodes (ICLN) and spleens from all pigs on BD, NF, and LC-F, but only 50% of spleens from pigs on LZ-F. Pigs had a dynamic spatial and temporal immune response to Salmonella infection and dietary treatments, as indicated by up- and downregulation in gene expression of inflammatory cytokines (interleukin (IL)-1β, IL-6, IL-10, interferon-γ, and tumor necrosis factor) in the ileum, ICLN, and spleen. The alternation in cytokine expression by fermented feed, particularly LZ-F, appeared to benefit pigs in combating Salmonella infection.

  17. The architecture and ppGpp-dependent expression of the primary transcriptome of Salmonella Typhimurium during invasion gene expression

    Directory of Open Access Journals (Sweden)

    Ramachandran Vinoy K

    2012-01-01

    Full Text Available Abstract Background Invasion of intestinal epithelial cells by Salmonella enterica serovar Typhimurium (S. Typhimurium requires expression of the extracellular virulence gene expression programme (STEX, activation of which is dependent on the signalling molecule guanosine tetraphosphate (ppGpp. Recently, next-generation transcriptomics (RNA-seq has revealed the unexpected complexity of bacterial transcriptomes and in this report we use differential RNA sequencing (dRNA-seq to define the high-resolution transcriptomic architecture of wild-type S. Typhimurium and a ppGpp null strain under growth conditions which model STEX. In doing so we show that ppGpp plays a much wider role in regulating the S. Typhimurium STEX primary transcriptome than previously recognised. Results Here we report the precise mapping of transcriptional start sites (TSSs for 78% of the S. Typhimurium open reading frames (ORFs. The TSS mapping enabled a genome-wide promoter analysis resulting in the prediction of 169 alternative sigma factor binding sites, and the prediction of the structure of 625 operons. We also report the discovery of 55 new candidate small RNAs (sRNAs and 302 candidate antisense RNAs (asRNAs. We discovered 32 ppGpp-dependent alternative TSSs and determined the extent and level of ppGpp-dependent coding and non-coding transcription. We found that 34% and 20% of coding and non-coding RNA transcription respectively was ppGpp-dependent under these growth conditions, adding a further dimension to the role of this remarkable small regulatory molecule in enabling rapid adaptation to the infective environment. Conclusions The transcriptional architecture of S. Typhimurium and finer definition of the key role ppGpp plays in regulating Salmonella coding and non-coding transcription should promote the understanding of gene regulation in this important food borne pathogen and act as a resource for future research.

  18. QUANTIFICATION OF Salmonella Typhimurium REDUCTION DURING COLD STORAGE OF RAW SHRIMPS IN THE PRESENCE OF SODIUM METABISULFITE [Kuantifikasi Reduksi Salmonella Typhimurium pada Udang Segar selama Penyimpanan Dingin dengan Penambahan Natrium Metabisulfit

    Directory of Open Access Journals (Sweden)

    Andiarto Yanuardi3

    2012-12-01

    Full Text Available Prediction of bacterial growth, survival or reduction in food matrices is needed for microbiological risk assessment. The survival of Salmonella Typhimurium on surfaces of raw shrimps at low temperature was studied, in the presence of sodium metabisulfite which is often used to prevent melanosis. The growth and/or reduction rates were quantified using DMFit software with Baranyi model and or linear model. The result showed that without sodium metabisulfite (control, when the initial level was high (105 CFU/ml, S. Typhimurium grew with a lag phase of 51.99±7.46 h and a growth rate of 0.01±0.002 log CFU.ml-1.h-1 on raw shrimps during storage at 8±2°C. When 1.5% (w/w sodium metabisulfite, a maximum level that often used to prevent melanosis, was added under the same condition, the number of S. Typhimurium was reduced for 5 log CFU/ml after 5 days, with a reduction rate of -0.03±0.001 log CFU.ml-1.h-1. This study indicated that Baranyi model can be used to predict the growth of S. Typhimurium on raw shrimp at low temperature, when sodium metabisulfite is absent. However, when sodium metabisulfite is present, at least 0.4% as found in this study, the reduction of S. Typhimurium can be predicted using a simple linear model.

  19. Tumor-targeting Salmonella typhimurium A1-R prevents experimental human breast cancer bone metastasis in nude mice

    OpenAIRE

    Miwa, Shinji; Yano, Shuya; Zhang, Yong; Matsumoto,Yasunori; Uehara, Fuminari; Yamamoto, Mako; Hiroshima, Yukihiko; Kimura, Hiroaki; Hayashi, Katsuhiro; Yamamoto, Norio; Bouvet, Michael; Tsuchiya, Hiroyuki; Hoffman, Robert M.; Zhao, Ming

    2014-01-01

    Bone metastasis is a lethal and morbid late stage of breast cancer that is currently treatment resistant. More effective mouse models and treatment are necessary. High bone-metastatic variants of human breast cancer cells were selected in nude mice by cardiac injection. After cardiac injection of a high bone-metastatic variant of breast cancer, all untreated mice had bone metastases compared to only 20% with parental cells. Treatment with tumor-targeting Salmonella typhimurium A1-R completely...

  20. A functional cra gene is required for Salmonella enterica serovar typhimurium virulence in BALB/c mice

    DEFF Research Database (Denmark)

    Allen, J. H.; Utley, M.; Van den Bosch, H.

    2000-01-01

    A minitransposon mutant of Salmonella enterica serovar Typhimurium SR-11, SR-11 Fad(-), is unable to utilize gluconeogenic substrates as carbon sources and is avirulent and immunogenic when administered perorally to BALB/c mice (M. J. Utley et al., FEMS Microbiol. Lett., 163:129-134, 1998). Here......, evidence is presented that the mutation in SR-11 Fad(-) that renders the strain avirulent is in the cra gene, which encodes the Cra protein, a regulator of central carbon metabolism....

  1. Mutagenicity of ptaquiloside, the carcinogen in bracken, and its related illudane-type sesquiterpenes. I. Mutagenicity in Salmonella typhimurium.

    Science.gov (United States)

    Nagao, T; Saito, K; Hirayama, E; Uchikoshi, K; Koyama, K; Natori, S; Morisaki, N; Iwasaki, S; Matsushima, T

    1989-12-01

    Ptaquiloside, a potent carcinogen of an illudane-type sesquiterpene glycoside isolated from Pteridium aquilinum, and its related compounds, hypolosides having the same nucleus isolated from the Pteridaceae, exhibited marked mutagenicity in the modified Ames test with Salmonella typhimurium TA98 and TA100 using a preincubation at pH 8.5. Illudins M and S, sesquiterpenes of the same illudane type from basidiomycetes, also exhibited mutagenicity. The structural requirements for mutagenicity are discussed.

  2. Interaction between Food-borne Pathogens (Campylobacter jejuni, Salmonella Typhimurium and Listeria monocytogenes) and a Common Soil Flagellate (Cercomonas sp.)

    DEFF Research Database (Denmark)

    Bui, Thanh Xuan; Wolff, Anders; Madsen, Mogens

    2012-01-01

    understood. In this study, we investigated the interactions between a common soil flagellate, Cercomonas sp., and three different bacterial pathogens (Campylobacter jejuni, Salmonella Typhimurium, and Listeria monocytogenes). Rapid growth of flagellates was observed in co-culture with C. jejuni and S....... The results of this study suggest that Cercomonas sp. and perhaps other soil flagellates may play a role for the survival of food-borne pathogens on plant surfaces and in soil....

  3. Effect of grinding intensity and feed physical form on in vitro adhesion of Salmonella Typhimurium and mannose residues in intestinal mucus receptors for salmonellae.

    Science.gov (United States)

    Callies, A; Sander, S J; Verspohl, J; Beineke, A; Kamphues, J

    2012-12-01

    The hypothesis of this study was that feeding a fine, pelleted diet (FP) compared to a coarse meal diet (CM) results in a higher mannose content in the intestinal mucus of pigs and therefore an increased in vitro adhesion of Salmonella Typhimurium DT104 L to the mucus. The 2 diets were fed to a total of 24 weaned pigs for 6 wk after which mannose content in the mucus was evaluated histochemically using the α1-3-d-mannose-specific lectin Galanthus nivalis agglutinin. The crypt width was determined as an indirect measure for the amount of secreted mucus. Ileal and cecal tissue samples were incubated with approximately 7.77 × 10(7) cfu Salmonella Typhimurium and numbers of salmonellae adhering to the mucus and/or mucosa were determined by culture techniques. There was no effect of feed physical form on the in vitro adhesion of S. Typhimurium either in the ileum (7.1 ± 0.19 log(10) cfu/g tissue) or in the cecum (6.8 ± 0.26 log(10) cfu/g). The mannose content of the mucus also did not differ between the treatment groups. The crypts of the duodenum, jejunum, and cecum were wider (P feeding the CM diet. This might be an indication for a higher mucus production in these pigs.

  4. Immunity to experimental Salmonella typhimurium infections in rats. Transfer of immunity with primed CD45RC+ and CD45RC- CD4 T-cell subpopulations

    DEFF Research Database (Denmark)

    Thygesen, P; Christensen, H B; Hougen, H P

    1996-01-01

    The protective effect of primed CD4 T cells against a lethal dose of Salmonella typhimurium was studied in Lewis rats. Primed CD4 T cells were obtained by inoculating Lewis rats with a non-lethal dose of S. typhimurium. Four weeks after the infection, spleen CD4 T cells were separated by antibody....... typhimurium. Transfer of CD45RC+ and CD45RC- CD4 T cells induced a significant survival, p = 0.022 and p = 0.023 respectively, following inoculation with S. typhimurium compared to animals with no cells transferred. The infection induced an increase in CD4 T cells expressing the CD45RC isoform compared...

  5. Feed gas effect on plasma inactivation mechanism of Salmonella Typhimurium in onion and quality assessment of the treated sample.

    Science.gov (United States)

    Khan, Muhammad Saiful Islam; Lee, Eun-Jung; Hong, Suk-In; Kim, Yun-Ji

    2017-12-18

    A submerged dielectric barrier discharge (DBD) plasma reactor was used to inactivate artificially inoculated reference strains of Salmonella Typhimurium ATCC 14028 on sliced onion (3 cm × 3 cm). Salmonella Typhimurium reductions obtained after 10 min of treatment were 3.96 log CFU/slice and 1.64 log CFU/slice for clean dry air and N2 feed gas, respectively. Variations observed in Optical Emission Spectra (OES) for different feed gases are responsible for the inactivation level variations of Salmonella Typhimurium. The physiochemical properties of the onion slices, such as quercetin content, ascorbic acid content and color parameters, were monitored before and after treatment and the changes that occurred were measured to be in the acceptable range. Quercetin content was reduced only 3.74-5.07% for 10 min treatment, higher reduction was obtained for the use of clean dry air than that of N2 feed gas. Ascorbic acid loss was measured to be 11.82% and 7.98% for a 10 min treatment with clean dry air and N2 feed gas, respectively. The color parameters did not show significant changes upon treatment (p > 0.05) of the same duration for the uses of different feed gases.

  6. A Salmonella Typhimurium-Typhi genomic chimera: a model to study Vi polysaccharide capsule function in vivo.

    Directory of Open Access Journals (Sweden)

    Angela M Jansen

    2011-07-01

    Full Text Available The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi(+, harbouring the Salmonella pathogenicity island (SPI-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi(+ colonised and persisted in mice at similar levels compared to the parent strain, S. Typhimurium C5. However, the innate immune response to infection with C5.507 Vi(+ and SGB1, an isogenic derivative not expressing Vi, differed markedly. Infection with C5.507 Vi(+ resulted in a significant reduction in cellular trafficking of innate immune cells, including PMN and NK cells, compared to SGB1 Vi(- infected animals. C5.507 Vi(+ infection stimulated reduced numbers of TNF-α, MIP-2 and perforin producing cells compared to SGB1 Vi(-. The modulating effect associated with Vi was not observed in MyD88(-/- and was reduced in TLR4(-/- mice. The presence of the Vi capsule also correlated with induction of the anti-inflammatory cytokine IL-10 in vivo, a factor that impacted on chemotaxis and the activation of immune cells in vitro.

  7. Advanced high-power pulsed light device to decontaminate food from pathogens: effects on Salmonella typhimurium viability in vitro.

    Science.gov (United States)

    Luksiene, Z; Gudelis, V; Buchovec, I; Raudeliuniene, J

    2007-11-01

    The aim of this study was to construct an advanced high-power pulsed light device for decontamination of food matrix and to evaluate its antibacterial efficiency. Key parameters of constructed device-emitted light spectrum, pulse duration, pulse power density, frequency of pulses, dependence of emitted spectrum on input voltage, irradiation homogenicity, possible thermal effects as well as antimicrobial efficiency were evaluated. Antimicrobial efficiency of high-power pulsed light technique was demonstrated and evaluated by two independent methods - spread plate and Miles-Misra method. Viability of Salmonella typhimurium as function of a given light dose (number of pulses) and pulse frequency was examined. According to the data obtained, viability of Salmonella typhimurium reduced by 7 log order after 100 light pulses with power density 133 W cm(-2). In addition, data indicate, that the pulse frequency did not influence the outcome of pathogen inactivation in the region 1-5 Hz. Moreover, no hyperthermic effect was detected during irradiation even after 500 pulses on all shelves with different distance from light source and subsequently different pulse power density (0-252 W cm(-2)). Newly constructed high-power pulsed light technique is effective nonthermal tool for inactivation of Salmonella typhimurium even by 7 log order in vitro. Novel advanced high-power pulsed light device can be a useful tool for development of nonthermal food decontamination technologies.

  8. Epithelial entry rather than the ensuing systemic immune response determines the pathogenicity of two Salmonella enterica serovar Typhimurium strains in a mouse model

    DEFF Research Database (Denmark)

    Sørensen, Rikke Brandt; Petersen, Anne; Pedersen, Susanne Brix

    2013-01-01

    Most studies of Salmonella enterica serovar Typhimurium infection focus only on the pathogenicity of one strain. We investigated whether differences in pathogenicity of two wild-type S. Typhimurium strains; DT120 and SL1344, were related to gut invasion or the resulting immune response.Oral admin......Most studies of Salmonella enterica serovar Typhimurium infection focus only on the pathogenicity of one strain. We investigated whether differences in pathogenicity of two wild-type S. Typhimurium strains; DT120 and SL1344, were related to gut invasion or the resulting immune response...... in neutrophil apoptosis was observed and all mice survived until Day 8. This study reveals that two wild-type S. Typhimurium strains, despite evoking highly comparable immune responses upon intravenous injection, exhibit diverse pathogenicity in mice and thus suggests that differences in their invasiveness...... and survival during gut passage determines the success of the ensuing immune response....

  9. Genomic Analysis of Salmonella enterica Serovar Typhimurium Characterizes Strain Diversity for Recent U.S. Salmonellosis Cases and Identifies Mutations Linked to Loss of Fitness under Nitrosative and Oxidative Stress.

    Science.gov (United States)

    Hayden, Hillary S; Matamouros, Susana; Hager, Kyle R; Brittnacher, Mitchell J; Rohmer, Laurence; Radey, Matthew C; Weiss, Eli J; Kim, Katie B; Jacobs, Michael A; Sims-Day, Elizabeth H; Yue, Min; Zaidi, Mussaret B; Schifferli, Dieter M; Manning, Shannon D; Walson, Judd L; Miller, Samuel I

    2016-03-08

    Salmonella enterica serovar Typhimurium is one of the most common S. enterica serovars associated with U.S. foodborne outbreaks. S. Typhimurium bacteria isolated from humans exhibit wide-ranging virulence phenotypes in inbred mice, leading to speculation that some strains are more virulent in nature. However, it is unclear whether increased virulence in humans is related to organism characteristics or initial treatment failure due to antibiotic resistance. Strain diversity and genetic factors contributing to differential human pathogenicity remain poorly understood. We reconstructed phylogeny, resolved genetic population structure, determined gene content and nucleotide variants, and conducted targeted phenotyping assays for S. Typhimurium strains collected between 1946 and 2012 from humans and animals in the United States and abroad. Strains from recent U.S. salmonellosis cases were associated with five S. Typhimurium lineages distributed within three phylogenetic clades, which are not restricted by geography, year of acquisition, or host. Notably, two U.S. strains and four Mexican strains are more closely related to strains associated with human immunodeficiency virus (HIV)-infected individuals in sub-Saharan Africa than to other North American strains. Phenotyping studies linked variants specific to these strains in hmpA and katE to loss of fitness under nitrosative and oxidative stress, respectively. These results suggest that U.S. salmonellosis is caused by diverse S. Typhimurium strains circulating worldwide. One lineage has mutations in genes affecting fitness related to innate immune system strategies for fighting pathogens and may be adapting to immunocompromised humans by a reduction in virulence capability, possibly due to a lack of selection for its maintenance as a result of the worldwide HIV epidemic. Nontyphoidal Salmonella bacteria cause an estimated 1.2 million illnesses annually in the United States, 80 million globally, due to ingestion of

  10. Evaluation of the addition of charcoals to broiler diets on the recovery of Salmonella Typhimurium during grow-out and processing

    Science.gov (United States)

    Two experiments evaluated prebiotics added to feed on the recovery of Salmonella in broilers during grow-out and processing. In experiment 1, "seeder" chicks were inoculated with Salmonella Typhimurium and placed with penmates. Treatments were: basal control, 0.3% bamboo charcoal, 0.6% bamboo charco...

  11. Effects of P22 bacteriophage on salmonella Enterica subsp. enterica serovar Typhimurium DMC4 strain biofilm formation and eradication

    Directory of Open Access Journals (Sweden)

    Karaca Basar

    2015-01-01

    Full Text Available Over the last decades, several antimicrobial agents have been made available. Due to increasing antimicrobial resistance, bacteriophages were rediscovered for their potential applications against bacterial infections. In the present study, biofilm inhibition and eradication of Salmonella enterica subsp. enterica serovar Typhimurium DMC4 strain (S. Typhimurium was evaluated with respect to different incubation periods at different P22 phage titrations. The efficacy of P22 phage on biofilm formation and eradication of S. Typhimurium DMC4 strain was screened in vitro on polystyrene and stainless steel surfaces. The biofilm forming capacity of S. Typhimurium was significantly reduced at higher phage titrations (106 pfu/mL ≤. All phage titers (104-108 pfu/mL were found to be effective at the end of the 24 h-incubation period whereas higher phage titrations were found to be effective at the end of the 48 h and 72 h of incubation. P22 phage has less efficacy on already formed, especially mature biofilms (72 h-old biofilm. Notable results of P22 phage treatment on S. Typhimurium biofilm suggest that P22 phage has potential uses in food systems.

  12. DNA methylation-dependent regulation of pef expression in Salmonella typhimurium.

    Science.gov (United States)

    Nicholson, B; Low, D

    2000-02-01

    Plasmid-encoded fimbriae (Pef) expressed by Salmonella typhimurium mediate adhesion to mouse intestinal epithelium. The pef operon shares features with the Escherichia coli pyelonephritis-associated pilus (pap) operon, which is under methylation-dependent transcriptional regulation. These features include conserved DNA GATC box sites in the upstream regulatory region as well as homologues of the PapI and PapB regulatory proteins. Unlike Pap fimbriae, which are expressed in a variety of laboratory media, Pef fimbriae were expressed only in acidic, rich broth under standing culture conditions. Analysis of S. typhimurium grown under these conditions indicated that Pef production was regulated by a phase variation mechanism, in which the bacterial population was skewed between fimbrial expression (phase ON) and non-expression (phase OFF) states. Leucine-responsive regulatory protein (Lrp) and DNA adenine methylase (Dam) were required for pef transcription. In contrast, the histone-like protein (H-NS) and the stationary-phase sigma factor (RpoS) repressed pef transcription. Methylation of the pef GATC II site appeared to be required for pef fimbrial expression based on analysis of a GCTC II mutant that did not express Pef fimbriae. Analysis of the DNA methylation states of pef GATC sites indicated that, under acidic growth conditions, which induced Pef production, most GATC I sites were non-methylated, whereas GATC II and GATC X were predominantly methylated. The methylation protection at GATC I and GATC II was dependent upon Lrp and was modulated by PefI. Together, these results indicate that Pef production is regulated by DNA methylation, which is the first example of methylation-dependent gene regulation outside of E. coli.

  13. Sub-inhibitory fosmidomycin exposures elicits oxidative stress in Salmonella enterica serovar Typhimurium LT2.

    Directory of Open Access Journals (Sweden)

    David T Fox

    Full Text Available Fosmidomycin is a time-dependent nanomolar inhibitor of methylerythritol phosphate (MEP synthase, which is the enzyme that catalyzes the first committed step in the MEP pathway to isoprenoids. Importantly, fosmidomycin is one of only a few MEP pathway-specific inhibitors that exhibits antimicrobial activity. Most inhibitors identified to date only exhibit activity against isolated pathway enzymes. The MEP pathway is the sole route to isoprenoids in many bacteria, yet has no human homologs. The development of inhibitors of this pathway holds promise as novel antimicrobial agents. Similarly, analyses of the bacterial response toward MEP pathway inhibitors provides valuable information toward the understanding of how emergent resistance may ultimately develop to this class of antibiotics. We have examined the transcriptional response of Salmonella enterica serovar typhimurium LT2 to sub-inhibitory concentrations of fosmidomycin via cDNA microarray and RT-PCR. Within the regulated genes identified by microarray were a number of genes encoding enzymes associated with the mediation of reactive oxygen species (ROS. Regulation of a panel of genes implicated in the response of cells to oxidative stress (including genes for catalases, superoxide dismutases, and alkylhydrogen peroxide reductases was investigated and mild upregulation in some members was observed as a function of fosmidomycin exposure over time. The extent of regulation of these genes was similar to that observed for comparable exposures to kanamycin, but differed significantly from tetracycline. Furthermore, S. typhimurium exposed to sub-inhibitory concentrations of fosmidomycin displayed an increased sensitivity to exogenous H2O2 relative to either untreated controls or kanamycin-treated cells. Our results suggest that endogenous oxidative stress is one consequence of exposures to fosmidomycin, likely through the temporal depletion of intracellular isoprenoids themselves, rather than

  14. Radiosensitivity of E.coli O157: H7 and Salmonella typhimurium on swiss chard

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marco A.S.; Mastro, Nelida L. del [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: masperei@ipen.br; nlmastro@ipen.br

    2007-07-01

    Swiss Chard is a beet (Beta vulgaris cicla) producing large yellowish green leaves with thick succulent stalks and often cooked as a potherb, called also seakale beet or chard. It is a nutritive vegetable rich in potassium, calcium, magnesium, sodium, phosphorus and vitamin C. Ionising radiation is an effective method to reduce pathogens. Radiation sensitivity of bacteria, however, depends on several factors. Particularly, few data are available on the ability of low-dose ionizing radiation to inactivate pathogenic bacteria on ready to eat vegetables. The aim of this study was the evaluation of the radiation sensitivity of pathogens experimentally contaminating the mentioned vegetable. Swiss chard leaves minimally processed were inoculated separately either with E. coli O157:H7 or Salmonella typhimurium by immersion to contain 6 log CFU/g and 1h later gamma-irradiated with 0.25 kGy, 0.5 kGy, 1 kGy and 1.5 kGy, dose rate of 2.94 kGy/h. The assay of pathogen survivors was made by direct plating. After applying a radiation dose of 0.5 kGy reductions of at least 3 log were achieved for both bacteria. The average D10 values, the radiation dose needed to inactivate 1 log of pathogen were 0.12 and 0.10 for E.coli O157:H7 and S.typhimurium respectively. These results indicate that irradiation may be an effective means for inactivating common foodborne pathogens that can eventually contaminate ready to eat vegetables. (author)

  15. Antimutagenic Properties of Basil (Ocimum basilicum L. in Salmonella typhimurium TA100

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    Olivera Stajković

    2007-01-01

    Full Text Available The use of dietary antimutagens and anticarcinogens has been seen as a promising approach to the protection of human health. Basil (Ocimum basilicum L. is a well-known medicinal and aromatic plant, with a range of newly discovered biological activities possibly important for chemoprevention. In the preliminary experiments, toxic and mutagenic potential of essential oil (EO from basil and pure substances: linalool, ß-myrcene and 1,8-cineole were tested using Salmonella typhimurium TA98, TA100 and TA102, with and without S9 mix (microsomal fraction of rat liver. No mutagenic effect of basil derivatives was detected in any tested strain. Antimutagenic effects of essential oil from basil and its pure constituents were further evaluated in the Ames test using S. typhimurium TA100. UVC irradiation and three chemical mutagens, 4-nitroquinoline-N-oxide (4NQO, 2-nitropropane (2-NP and benzo(apyrene (B(aP were used to induce mutagenesis. All tested basil derivatives significantly reduced UV-induced mutations. The maximum inhibition was in the range of 64–77 %. Inhibitory potential against direct acting model mutagen/carcinogen 4NQO was similar to UV (52–67 %. In the presence of S9, EO and 1,8-cineole showed moderate inhibition of 2-NP induced mutagenesis, while the remaining two substances had no effect. Linalool exhibited high co-mutagenic effect with B(aP, 1,8-cineole showed moderate inhibitory effect against B(aP-induced mutations, while EO and ß-myrcene were ineffective.

  16. AKTIVITAS REACTIVE OXYGEN SPECIES MAKROFAG AKIBAT STIMULASI GEL LIDAH BUAYA PADA INFEKSI Salmonella typhimurium

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    R. Susanti

    2012-09-01

    Full Text Available Reactive Oxygen Species (ROS merupakan salah satu lethal chemical yang dapatmembunuh dan mengeliminasi bakteri pada sel fagosit. Lidah Buaya (Aloevera banyak dipakai sebagai pengobatan tradisional, tetapi belum ada buktiilmiah sampai tingkat seluler apalagi subseluler dalam hal efek imunostimulanpada penyakit infeksi. Tujuan penelitian ini adalah untuk mengetahui aktivitasimunostimulan dari gel lidah buaya yang ditunjukkan oleh aktivitas ROS makrofagsecara in vivo terhadap infeksi bakteri patogen Salmonella typhimurium. Sebanyak24 ekor mencit BABL/c betina umur 8-10 minggu berat 20-30 gram dikelompokkansecara acak menjadi empat kelompok, masing-masing kelompok enam ekor.Kelompok kontrol tidak diberi gel Aloe vera, sementara kelompok P1, P2, dan P3berturut-turut diberi gel Aloe vera 0,5 ml/ekor/hari; 1,0 ml/ekor/hari, dan 1,5ml/ekor/hari. Pemberian gel Aloe vera dilakukan selama sembilan hari. Pada harike-6, mencit diinfeksi bakteri patogen Salmonella typhimurium intraperitoneal105 CFU. Selanjutnya pada hari ke-10 mencit didislokasi dan dibedah, diambilmakrofag dari peritoneum untuk dianalisis produksi ROS-nya. Hasil penelitianmenunjukkan bahwa pemberian gel Aloe vera berpengaruh signi..ikan terhadappeningkatan produksi ROS makrofag mencit BALB/c yang diinfeksi Salmonellatyphimurium. Terdapat perbedaan secara signi..ikan antara kelompok kontroldengan kelompok P1, P2, dan P3, tetapi tidak terdapat perbedaan signi..ikan antarkelompok P1, P2, dan P3. Pemberian gel Aloe vera dosis 0,5 ml/ekor/hari sudahmampu meningkatkan produksi ROS makrofag. Reactive Oxygen Species (ROS is one of lethal chemicals that can kill and eliminatebacteria in phagocytic cells. Aloe vera is widely used as traditional medicine, but thereis no scienti..ic evidence to prove the effect of immunostimulatory of the Aloe vera gel oninfectious disease in the cellular or subcellular level. This research aims to determinethe immunostimulatory activity of Aloe vera gel showed by

  17. LPS structure and PhoQ activity are important for Salmonella Typhimurium virulence in the Galleria mellonella infection model [corrected].

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    Jennifer K Bender

    Full Text Available The larvae of the wax moth, Galleria mellonella, have been used experimentally to host a range of bacterial and fungal pathogens. In this study we evaluated the suitability of G. mellonella as an alternative animal model of Salmonella infection. Using a range of inoculum doses we established that the LD₅₀ of SalmonellaTyphimurium strain NCTC 12023 was 3.6 × 10³ bacteria per larva. Further, a set of isogenic mutant strains depleted of known virulence factors was tested to identify determinants essential for S. Typhimurium pathogenesis. Mutants depleted of one or both of the type III secretion systems encoded by Salmonella Pathogenicity Islands 1 and 2 showed no virulence defect. In contrast, we observed reduced pathogenic potential of a phoQ mutant indicating an important role for the PhoPQ two-component signal transduction system. Lipopolysaccharide (LPS structure was also shown to influence Salmonella virulence in G. mellonella. A waaL(rfaL mutant, which lacks the entire O-antigen (OAg, was virtually avirulent, while a wzz(ST/wzz(fepE double mutant expressing only a very short OAg was highly attenuated for virulence. Furthermore, shortly after infection both LPS mutant strains showed decreased replication when compared to the wild type in a flow cytometry-based competitive index assay. In this study we successfully established a G. mellonella model of S. Typhimurium infection. By identifying PhoQ and LPS OAg length as key determinants of virulence in the wax moth larvae we proved that there is an overlap between this and other animal model systems, thus confirming that the G. mellonella infection model is suitable for assessing aspects of Salmonella virulence function.

  18. LPS Structure and PhoQ Activity Are Important for Salmonella Typhimurium Virulence in the Gallleria mellonella Infection Model

    Science.gov (United States)

    Bender, Jennifer K.; Wille, Thorsten; Blank, Kathrin; Lange, Anna; Gerlach, Roman G.

    2013-01-01

    The larvae of the wax moth, Galleria mellonella, have been used experimentally to host a range of bacterial and fungal pathogens. In this study we evaluated the suitability of G. mellonella as an alternative animal model of Salmonella infection. Using a range of inoculum doses we established that the LD50 of Salmonella Typhimurium strain NCTC 12023 was 3.6 × 103 bacteria per larva. Further, a set of isogenic mutant strains depleted of known virulence factors was tested to identify determinants essential for S. Typhimurium pathogenesis. Mutants depleted of one or both of the type III secretion systems encoded by Salmonella Pathogenicity Islands 1 and 2 showed no virulence defect. In contrast, we observed reduced pathogenic potential of a phoQ mutant indicating an important role for the PhoPQ two-component signal transduction system. Lipopolysaccharide (LPS) structure was also shown to influence Salmonella virulence in G. mellonella. A waaL (rfaL) mutant, which lacks the entire O-antigen (OAg), was virtually avirulent, while a wzzST/wzzfepE double mutant expressing only a very short OAg was highly attenuated for virulence. Furthermore, shortly after infection both LPS mutant strains showed decreased replication when compared to the wild type in a flow cytometry-based competitive index assay. In this study we successfully established a G. mellonella model of S. Typhimurium infection. By identifying PhoQ and LPS OAg length as key determinants of virulence in the wax moth larvae we proved that there is an overlap between this and other animal model systems, thus confirming that the G. mellonella infection model is suitable for assessing aspects of Salmonella virulence function. PMID:23951347

  19. Movement of Salmonella serovar Typhimurium and E. coli O157:H7 to Ripe Tomato Fruit Following Various Routes of Contamination.

    Science.gov (United States)

    Deering, Amanda J; Jack, Dan R; Pruitt, Robert E; Mauer, Lisa J

    2015-11-05

    Salmonella serovars have been associated with the majority of foodborne illness outbreaks involving tomatoes, and E. coli O157:H7 has caused outbreaks involving other fresh produce. Contamination by both pathogens has been thought to originate from all points of the growing and distribution process. To determine if Salmonella serovar Typhimurium and E. coli O157:H7 could move to the mature tomato fruit of different tomato cultivars following contamination, three different contamination scenarios (seed, leaf, and soil) were examined. Following contamination, each cultivar appeared to respond differently to the presence of the pathogens, with most producing few fruit and having overall poor health. The Micro-Tom cultivar, however, produced relatively more fruit and E. coli O157:H7 was detected in the ripe tomatoes for both the seed- and leaf- contaminated plants, but not following soil contamination. The Roma cultivar produced fewer fruit, but was the only cultivar in which E. coli O157:H7 was detected via all three routes of contamination. Only two of the five cultivars produced tomatoes following seed-, leaf-, and soil- contamination with Salmonella Typhimurium, and no Salmonella was found in any of the tomatoes. Together these results show that different tomato cultivars respond differently to the presence of a human pathogen, and for E. coli O157:H7, in particular, tomato plants that are either contaminated as seeds or have a natural opening or a wound, that allows bacteria to enter the leaves can result in plants that have the potential to produce tomatoes that harbor internalized pathogenic bacteria.

  20. Oral delivery of the Sj23LHD-GST antigen by Salmonella typhimurium type III secretion system protects against Schistosoma japonicum infection in mice.

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    Guo Chen

    2011-09-01

    Full Text Available BACKGROUND: Schistosomiasis japonica is a zoonotic parasitic disease and oral vaccine delivery system would be benefit for prevention of this disease. Although attenuated salmonella has been used as an antigen expression vector for oral vaccine development, the membrane-bound vacuoles in which bacteria reside hinders the presentation of expressed heterologous antigens to the major histocompatibility complex (MHC molecules. The present work used an attenuated Salmonella typhimurium strain VNP20009 to secretory expression of Sj23LHDGST bivalent antigen from Schistosoma japonicum and tested the protective efficacy against S. japonicum infection in orally immunized mice. METHODOLOGY/PRINCIPAL FINDINGS: Promoters (nirB or pagC were used to express the antigen (Sj23LHDGST and the Salmonella type III or α-hemolysin secretion system was employed to secrete it. The immunoblotting analysis and fluorescent microscopy revealed that the antigen was effectively expressed and delivered to the cytosol of macrophages in vitro. Among recombinant vaccine strains, an engineered VNP20009 which expressed the antigen by nirB promoter and secreted it through type III secretion system (nirB-sopE(1-104-Sj23LHD-GST efficiently protected against S. japonicum infection in a mouse model. This strain elicited a predominantly IgG(2a antibody response and a markedly increase in the production of IL-12 and IFN-γ. The flow cytometric analysis demonstrated that this strain caused T cell activation as evidenced by significantly increased expression of CD44 and CD69. CONCLUSION/SIGNIFICANCE: Oral delivery of antigen by nirB-driven Salmonella typhimurium type III secretion system is a novel, safe, inexpensive, efficient and convenient approach for schistosome vaccine development.

  1. Salmonella enterica Serovar Typhimurium in Mauritius Linked to Consumption of Marlin Mousse

    DEFF Research Database (Denmark)

    Issack, M. I.; Hendriksen, Rene S.; Lun, P. L. K.

    2009-01-01

    We report the first outbreak of salmonellosis caused by consumption of contaminated marlin mousse. Between 29 October and 5 November 2008, at least 53 persons developed diarrheal illness, all with a history of eating marlin mousse. Salmonella spp. that did not produce gas from glucose was isolated...

  2. Estudio de un brote intrahospitalario por Salmonella typhimurium productora de beta-lactamasa de espectro extendido SHV-5

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    Liliana Del Pozo

    2006-10-01

    Full Text Available Antecedentes: Presencia de un brote intrahospitalario de Salmonella typhimurium productora de beta-lactamasas de espectro extendido ocurrido en el Hospital San Bartolome, entre el 17 de febrero y el 6 de marzo del año 2001. Objetivo: Identificar los mecanismos implicados en la transmisión de Salmonella typhimurium y caracterización de los genes asociados a la resistencia en beta-lactámicos. Diseño: Estudio clínico-bacteriológico retrospectivo. Lugar: Hospital Nacional Docente Madre Niño (Honadomani San Bartolomé. Materiales biológicos: Aislamientos bacterianos provenientes de pacientes lactantes. Intervenciones: Se determinó la diversidad genética de cinco aislamientos bacterianos provenientes de pacientes lactantes hospitalizados en la Unidad pediátrica del hospital, utilizando REP-PCR y fingerprint plasmídico. Previamente, se caracterizó la resistencia antimicrobiana, determinando la presencia de beta-lactamasa de espectro extendido mediante la prueba de sinergia de doble disco; la variante fue identificada por PCR-secuenciamiento del gen bla shv . Principales medidas de resultados: Presencia de genotipos, plásmidos y beta-lactamasa de Salmonella typhimurium. Resultados: Se determinó la presencia de dos genotipos en los aislamientos de Salmonella typhimurium; el caso índice (sensible presentó un genotipo diferente al de otros aislamientos resistentes pertenecientes a pacientes hospitalizados. Se determinó la presencia en S. typhimurium de un plásmido de peso molecular elevado de tamaño distinto a los de K. pneumoniae, pero probablemente relacionado con una cepa de E. coli intrahospitalaria. Se encontró la beta-lactamasa de espectro extendido SHV-5 en los aislamientos de S. typhimurium y E. coli. Conclusiones: El estudio sugiere que la diseminación de estas bacterias en los lactantes puede haber sido favorecida por varios factores que habrían intervenido en la transferencia de elementos genéticos responsables de la

  3. Tigecycline challenge triggers sRNA production in Salmonella enterica serovar Typhimurium

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    Yu Jing

    2012-09-01

    Full Text Available Abstract Background Bacteria employ complex transcriptional networks involving multiple genes in response to stress, which is not limited to gene and protein networks but now includes small RNAs (sRNAs. These regulatory RNA molecules are increasingly shown to be able to initiate regulatory cascades and modulate the expression of multiple genes that are involved in or required for survival under environmental challenge. Despite mounting evidence for the importance of sRNAs in stress response, their role upon antibiotic exposure remains unknown. In this study, we sought to determine firstly, whether differential expression of sRNAs occurs upon antibiotic exposure and secondly, whether these sRNAs could be attributed to microbial tolerance to antibiotics. Results A small scale sRNA cloning strategy of Salmonella enterica serovar Typhimurium SL1344 challenged with half the minimal inhibitory concentration of tigecycline identified four sRNAs (sYJ5, sYJ20, sYJ75 and sYJ118 which were reproducibly upregulated in the presence of either tigecycline or tetracycline. The coding sequences of the four sRNAs were found to be conserved across a number of species. Genome analysis found that sYJ5 and sYJ118 mapped between the 16S and 23S rRNA encoding genes. sYJ20 (also known as SroA is encoded upstream of the tbpAyabKyabJ operon and is classed as a riboswitch, whilst its role in antibiotic stress-response appears independent of its riboswitch function. sYJ75 is encoded between genes that are involved in enterobactin transport and metabolism. Additionally we find that the genetic deletion of sYJ20 rendered a reduced viability phenotype in the presence of tigecycline, which was recovered when complemented. The upregulation of some of these sRNAs were also observed when S. Typhimurium was challenged by ampicillin (sYJ5, 75 and 118; or when Klebsiella pneumoniae was challenged by tigecycline (sYJ20 and 118. Conclusions Small RNAs are overexpressed as a result of

  4. Production of IgY by layers injected with Salmonella typhimurium

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    Hee, H. L.

    2017-06-01

    Full Text Available In the present study, production of IgY and performance of layers immunised with Salmonella typhimurium were evaluated. Thirty 23-wk old layers (Lohmann Brown with average body weight of 1.6 � 0.03 kg. were randomly and equally divided into two groups. Both groups were placed in a specific pathogen free room equipped with an exhaust fan. The layers were placed in single battery cages with slightly tilted floor which allowed eggs to roll straight into the collecting tray. Lyophilized, attenuated whole cells of S. typhimurium strain [serotype: Somatic (O, antigen 1, 4, (5, 12, flagella (H N12 phase I: 1; phase II: 1, 2 (Group B] that were emulsified with Freund�s complete adjuvant were used to immunise the layers intramuscularly 3 times at 2-wk interval (treatment group. Layers in the control group were injected with a solution of sterilized phosphate-buffered saline (PBS emulsified with an equal volume of Freund�s complete adjuvant. The experimental period lasted for 14 wks. Specific antibodies were detected by enzyme-linked immunosorbent assay. The results showed that the birds lost weight during the injection period, but the weights slowly increased in the following weeks. However, the weight of layers in the treated group remained lower (P<0.05 when compared to the period before injection. The loss in body weight of layers was the result of reduced feed intake, in particular during the injection weeks. Layers in the control group had a higher egg production, by about 10.1% than layers in the treatment group throughout the experimental period. The egg production for layers in treatment group showed a significant decrease (P<0.05 during the immunization period by 28.8%. The egg production significantly increased (P<0.05 to 71.9% after this period, but the production did not reach the level before immunisation. The weight of eggs of treated layers were significantly lower (P<0.05 than the control layers during the injection weeks. The egg

  5. A mutation in the poxA gene of Salmonella enterica serovar Typhimurium alters protein production, elevates susceptibility to environmental challenges, and decreases swine colonization.

    Science.gov (United States)

    Bearson, Shawn M D; Bearson, Bradley L; Brunelle, Brian W; Sharma, Vijay K; Lee, In Soo

    2011-06-01

    Control of foodborne Salmonella within the farm-retail continuum is a complex issue since over 2500 serovars of Salmonella exist, the host range of Salmonella spp. varies greatly, and Salmonella is environmentally ubiquitous. To identify Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) genes important for pathogen survival, our research group previously screened a signature-tagged mutagenesis bank in an ex vivo swine stomach content assay. A mutation in the poxA gene, a member of the gene family encoding class-II aminoacyl-tRNA synthetases, decreased survival of Salmonella Typhimurium in the ex vivo swine stomach content assay. In the current study, complementation with a plasmid-encoded poxA gene restored survival of the poxA mutant to the level of the parental, wild-type strain. In vivo analysis of the poxA mutant in the natural porcine host revealed significantly reduced fecal shedding of Salmonella, decreased colonization of the tonsils, and decreased detection of the mutant strain in the cecal contents of the pigs at 7 days postinoculation (p < 0.05). Body temperature (fever) of the pigs inoculated with wild-type Salmonella Typhimurium was significantly higher than that of pigs inoculated with the poxA mutant (p < 0.05). Two-dimensional gel electrophoresis revealed characteristic differences in the protein profile of the poxA mutant relative to the wild-type strain, indicating that deletion of poxA in Salmonella Typhimurium exerts selective effects on translation and/or posttranslational modifications of mRNA species that are necessary for stress survival and colonization of the natural swine host.

  6. wksl3, a New Biocontrol Agent for Salmonella enterica Serovars Enteritidis and Typhimurium in Foods: Characterization, Application, Sequence Analysis, and Oral Acute Toxicity Study

    OpenAIRE

    Kang, Hyun-Wol; Kim, Jae-Won; Jung, Tae-Sung; Woo, Gun-Jo

    2013-01-01

    Of the Salmonella enterica serovars, S. Enteritidis and S. Typhimurium are responsible for most of the Salmonella outbreaks implicated in the consumption of contaminated foods in the Republic of Korea. Because of the widespread occurrence of antimicrobial-resistant Salmonella in foods and food processing environments, bacteriophages have recently surfaced as an alternative biocontrol tool. In this study, we isolated a virulent bacteriophage (wksl3) that could specifically infect S. Enteritidi...

  7. Inactivation of Salmonella enterica serovar Typhimurium and quality maintenance of cherry tomatoes treated with gaseous essential oils.

    Science.gov (United States)

    Yun, Juan; Fan, Xuetong; Li, Xihong

    2013-03-01

    The antimicrobial activity of the essential oils (EOs) from cinnamon bark, oregano, mustard, and of their major components cinnamaldehyde, carvacrol, and allyl isothiocyanate (AIT) was evaluated as a gaseous treatment to reduce Salmonella enterica serovar Typhimurium in vitro and on tomatoes. In vitro tests showed that mustard EO and AIT had the greatest inhibition of Salmonella, followed by cinnamon EO and cinnamaldehyde, while oregano and carvacrol showed the least inhibition. Scanning electron microscopy images of S. Typhimurium on tomatoes suggest that the EOs and their major components damaged the bacteria, and the damage was more obvious after posttreatment storage at 10 °C for 4 and 7 d. Salmonella on inoculated tomatoes was reduced by more than 5 log colony forming units (CFU)/g by mustard EO and AIT, by 4.56 and 3.79 log CFU/g following cinnamon EO and cinnamaldehyde treatments, respectively, and 1.54 and 3.37 log CFU/g after oregano EO and carvacrol treatments, respectively. Mustard EO and AIT induced discoloration, softening, and loss of the vitamin C and lycopene during 21 d of storage at 10 °C, while treatment with cinnamon EO and cinnamaldehyde did not result in significant changes in tomato quality. Tomatoes treated with oregano EO had better quality than nontreated samples after storage. Therefore, treatment with cinnamon and oregano EO and their major components appeared to be feasible for inactivation of Salmonella on tomatoes and maintaining quality. © 2013 Institute of Food Technologists®

  8. Determination of Viable Salmonella Typhimurium Cells in Heat Treated Milk By PMA/Real-Time PCR Method

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    Zülal Kesmen

    2017-06-01

    Full Text Available Applying different technological processes during the production of food has a lethal effect on the bacteria but DNA of these bacterial strains may cause false positive results when detected by real time PCR technique because they preserve their existence for a certain period of time. To overcome this shortcoming of the real time PCR technique, a new method has been developed in recent years, based on the removal of dead cell DNA from the medium by treatment with Propodium Monoazide (PMA before DNA extraction. In this study, real-time PCR method was combined with PMA application for the detection of live cells of Salmonella Typhimurium in heat treated milk samples. For this purpose, milk samples inoculated with S. Tyhimurium were heat treated at different temperatures (60, 65, 70 and 75°C and times (15, 60, 300, 900 sec and number of live bacteria was determined comparatively by direct real-time PCR, PMA/real-time PCR and conventional cultural method. As a result, unlike the direct real time PCR technique, PMA/real-time PCR method prevents to a certain extent of false positive results from dead cells at all tested temperatures and times but higher results were obtained from PMA/real-time PCR method when compared to conventional cultural results. Therefore, further studies should be carried out to optimize the conditions of the PMA application in order to eliminate the high positive results detected by the PMA / real-time PCR method

  9. Salmonella Typhimurium induces SPI-1 and SPI-2 regulated and strain dependent downregulation of MHC II expression on porcine alveolar macrophages

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    Van Parys Alexander

    2012-06-01

    Full Text Available Abstract Foodborne salmonellosis is one of the most important bacterial zoonotic diseases worldwide. Salmonella Typhimurium is the serovar most frequently isolated from persistently infected slaughter pigs in Europe. Circumvention of the host’s immune system by Salmonella might contribute to persistent infection of pigs. In the present study, we found that Salmonella Typhimurium strain 112910a specifically downregulated MHC II, but not MHC I, expression on porcine alveolar macrophages in a Salmonella pathogenicity island (SPI-1 and SPI-2 dependent way. Salmonella induced downregulation of MHC II expression and intracellular proliferation of Salmonella in macrophages were significantly impaired after opsonization with Salmonella specific antibodies prior to inoculation. Furthermore, the capacity to downregulate MHC II expression on macrophages differed significantly among Salmonella strains, independently of strain specific differences in invasion capacity, Salmonella induced cytotoxicity and altered macrophage activation status. The fact that strain specific differences in MHC II downregulation did not correlate with the extent of in vitro SPI-1 or SPI-2 gene expression indicates that other factors are involved in MHC II downregulation as well. Since Salmonella strain dependent interference with the pig’s immune response through downregulation of MHC II expression might indicate that certain Salmonella strains are more likely to escape serological detection, our findings are of major interest for Salmonella monitoring programs primarily based on serology.

  10. Isolation of Salmonella enterica subsp. enterica (O:4,5:i and Salmonella enterica subsp. Typhimurium from free-living domestic pigeons (Columba livia

    Directory of Open Access Journals (Sweden)

    R.C. Rocha-e-Silva

    2014-10-01

    Full Text Available The present study reports the isolation of Salmonella enterica in organs of free-living domestic pigeons. In the clinic examination, the presence of feces in the peri-cloacal and abdominal regions were observed, as well as symptoms such as cachexy, incoordination and opisthotonos. Before any therapeutic protocol was applied the bird died and a necropsy was then performed for the removal of spleen, liver, kidney and intestine for bacteriological examination and antibiotic sensitivity test. Salmonella enterica subsp.enterica (O:4,5:i- and Salmonella enterica subsp. enterica serovar Typhimurium were isolated from the liver and intestine and the sensitivity test demonstrated that these strains are sensitive to several antibiotics.

  11. BcsZ inhibits biofilm phenotypes and promotes virulence by blocking cellulose production in Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Ahmad, Irfan; Rouf, Syed Fazle; Sun, Lei; Cimdins, Annika; Shafeeq, Sulman; Le Guyon, Soazig; Schottkowski, Marco; Rhen, Mikael; Römling, Ute

    2016-10-19

    Cellulose, a 1,4 beta-glucan polysaccharide, is produced by a variety of organisms including bacteria. Although the production of cellulose has a high biological, ecological and economical impact, regulatory mechanisms of cellulose biosynthesis are mostly unknown. Family eight cellulases are regularly associated with cellulose biosynthesis operons in bacteria; however, their function is poorly characterized. In this study, we analysed the role of the cellulase BcsZ encoded by the bcsABZC cellulose biosynthesis operon of Salmonella enterica serovar Typhimurium (S. Typhimurium) in biofilm related behavior. We also investigated the involvement of BcsZ in pathogenesis of S. Typhimurium including a murine typhoid fever infection model. In S. Typhimurium, cellulase BcsZ with a putative periplasmic location negatively regulates cellulose biosynthesis. Moreover, as assessed with a non-polar mutant, BcsZ affects cellulose-associated phenotypes such as the rdar biofilm morphotype, cell clumping, biofilm formation, pellicle formation and flagella-dependent motility. Strikingly, although upregulation of cellulose biosynthesis was not observed on agar plate medium at 37 °C, BcsZ is required for efficient pathogen-host interaction. Key virulence phenotypes of S. Typhimurium such as invasion of epithelial cells and proliferation in macrophages were positively regulated by BcsZ. Further on, a bcsZ mutant was outcompeted by the wild type in organ colonization in the murine typhoid fever infection model. Selected phenotypes were relieved upon deletion of the cellulose synthase BcsA and/or the central biofilm activator CsgD. Although the protein scaffold has an additional physiological role, our findings indicate that the catalytic activity of BcsZ effectively downregulates CsgD activated cellulose biosynthesis. Repression of cellulose production by BcsZ subsequently enables Salmonella to efficiently colonize the host.

  12. Salmonella Enterica Serovar Typhimurium BipA Exhibits Two Distinct Ribosome Binding Modes

    Energy Technology Data Exchange (ETDEWEB)

    deLivron, M.; Robinson, V

    2008-01-01

    BipA is a highly conserved prokaryotic GTPase that functions to influence numerous cellular processes in bacteria. In Escherichia coli and Salmonella enterica serovar Typhimurium, BipA has been implicated in controlling bacterial motility, modulating attachment and effacement processes, and upregulating the expression of virulence genes and is also responsible for avoidance of host defense mechanisms. In addition, BipA is thought to be involved in bacterial stress responses, such as those associated with virulence, temperature, and symbiosis. Thus, BipA is necessary for securing bacterial survival and successful invasion of the host. Steady-state kinetic analysis and pelleting assays were used to assess the GTPase and ribosome-binding properties of S. enterica BipA. Under normal bacterial growth, BipA associates with the ribosome in the GTP-bound state. However, using sucrose density gradients, we demonstrate that the association of BipA and the ribosome is altered under stress conditions in bacteria similar to those experienced during virulence. The data show that this differential binding is brought about by the presence of ppGpp, an alarmone that signals the onset of stress-related events in bacteria.

  13. Characterization of the Salmonella typhimurium pagC/pagD chromosomal region.

    Science.gov (United States)

    Gunn, J S; Alpuche-Aranda, C M; Loomis, W P; Belden, W J; Miller, S I

    1995-01-01

    The PhoP/PhoQ two-component system regulates Salmonella typhimurium genes that are essential to bacterial virulence and survival within macrophages. The best characterized of these PhoP-activated genes (pag) is pagC, which encodes a 188-amino-acid envelope protein (W. S. Pulkkinen and S. I. Miller, J. Bacteriol. 173:86-93, 1991). We here report the identification of four genes (pagD, envE, msgA, and envF) located 5' to pagC. Each gene is transcribed from its own promoter, two of which (msgA and pagD) were defined by primer extension analysis. Three of these genes (pagD, envE, and envF) are predicted to encode envelope proteins. The pagD gene is transcribed in a direction opposite from that of and adjacent to pagC and is positively regulated by PhoP/PhoQ. Transposon insertions within pagD and msgA attenuate bacterial virulence and survival within macrophages; however, deletion of pagD has no effect on virulence. The product of the envF gene is predicted to be a lipoprotein on the basis of the presence of a consensus lipid attachment site. The low G + C content of these genes and the homology of msgA to Shigella plasmid DNA suggest that this region may have been acquired by horizontal transmission. PMID:7665482

  14. An outbreak of Salmonella Typhimurium traced back to salami, Denmark, April to June 2010.

    Science.gov (United States)

    Kuhn, Kg; Torpdahl, M; Frank, C; Sigsgaard, K; Ethelberg, S

    2011-05-12

    Between April and June 2010, a small national outbreak of Salmonella Typhimurium with a particular multilocus variable-number tandem repeat analysis (MLVA) type was identified in Denmark through laboratory-based surveillance. The outbreak involved twenty cases, primarily living within the greater Copenhagen area. Half of the cases were children aged ten years or younger and 12 were male; three cases were hospitalised.A matched case-control study showed a strong link between illness and eating a particular salami product containing pork and venison, matched odds ratio(mOR):150, confidence interval (CI): 19–1,600. The salami had been produced in Germany. Microbiological confirmation in food samples was sought but not obtained. Danish consumers were notified that they should return or dispose of any packages from the suspected salami batch. Because the salami product had potentially been sold in other European countries, the European Centre for Disease Prevention and Control urgent enquiry and Rapid Alert System for Food and Feed systems were used to highlight the possibility of outbreaks in these countries. Case-control studies area strong tool in some outbreak investigations and evidence from such studies may give sufficient information to recall a food product.

  15. A Salmonella Typhimurium outbreak linked to Vietnamese bread rolls in South Western Sydney, Australia, 2015

    Science.gov (United States)

    Lord, Heidi; Fletcher-Lartey, Stephanie; Alexander, Kate; Egana, Nilva; Conaty, Stephen

    2017-01-01

    Introduction In September 2015, the South Western Sydney (SWS) Public Health Unit was notified of a cluster of Salmonella Typhimurium (STm) cases with a common multiple-locus variable-number tandem repeats analysis (MLVA) pattern. An investigation was conducted to identify a source and contain the outbreak. Methods The cluster was initially identified through routine geographic information system cluster scanning applied to the New South Wales Notifiable Conditions Management System. Additional cases were identified through a complaint to local council about a bakery. The bakery was inspected and 48 environmental and food swabs were collected for analysis. Results A total of 26 suspected cases were identified, of which 14 were interviewed. STm MLVA type 3–16–9-11–523 was identified in 19 of 26 case stool specimens. Most cases (12/14) consumed bread rolls containing pork or chicken with chicken liver pâté and raw egg mayonnaise filling. Five cases identified a common bakery exposure. Environmental and food samples from the bakery isolated STm with an identical MLVA pattern. Discussion An STm cluster in SWS was investigated and found to be linked to Vietnamese bread rolls containing pork or chicken with chicken liver pâté and raw egg mayonnaise filling. Confirmation of a distinct MLVA pattern among STm isolates from clinical, food and environmental samples provided evidence to establish an epidemiological link between the cases and the implicated premises and informed public health action to contain the outbreak. PMID:28736650

  16. Salmonella-Typhimurium phage types from human salmonellosis in denmark 1988 to 1993

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar; Baggesen, Dorte Lau; Gaarslev, K.

    1994-01-01

    A total of 989 isolates of Salmonella enterica ssp. enterica serovar Typhimurium from cases of human salmonellosis were investigated by phage typing, The isolates comprised all isolates recovered during the month of August in each of the years from 1988 to 1993. Phage typing assigned 82.......6% of the strains to 36 different definitive types, 11.9% of the strains belonged to types of unknown lysis pattern (RDNC), and 5.5% could not be typed by the phages used (NT). Three phage types (12, 66 and 110) made up approximately 50% of the isolates in each of the years investigated. During the period...... in question these types showed major changes in prevalence: phage type 12 increased from 4.0% in 1988 to a maximum of 55.2% in 1992, and phage type 66 and phage type 110 were reduced from 40.1% and 27.8% to a minimum of 3.9% and 4.8% in 1993 and 1992, respectively. The increasing prevalence of phage type 12...

  17. Antioxidant oils and Salmonella enterica Typhimurium reduce tumor in an experimental model of hepatic metastasis

    Directory of Open Access Journals (Sweden)

    Sorenson BS

    2011-05-01

    Full Text Available Brent S Sorenson, Kaysie L Banton, Lance B Augustin, Arnold S Leonard, Daniel A SaltzmanDepartment of Surgery, University of Minnesota Medical School, Minneapolis, MN, USAAbstract: Fruit seeds high in antioxidants have been shown to have anticancer properties and enhance host protection against microbial infection. Recently we showed that a single oral dose of Salmonella enterica serovar Typhimurium expressing a truncated human interleukin-2 gene (SalpIL2 is avirulent, immunogenic, and reduces hepatic metastases through increased natural killer cell populations in mice. To determine whether antioxidant compounds enhance the antitumor effect seen in SalpIL2-treated animals, we assayed black cumin (BC, black raspberry (BR, and milk thistle (MT seed oils for the ability to reduce experimental hepatic metastases in mice. In animals without tumor, BC and BR oil diets altered the kinetics of the splenic lymphocyte response to SalpIL2. Consistent with previous reports, BR and BC seed oils demonstrated independent antitumor properties and moderate adjuvant potential with SalpIL2. MT oil, however, inhibited the efficacy of SalpIL2 in our model. Based on these data, we conclude that a diet high in antioxidant oils promoted a more robust immune response to SalpIL2, thus enhancing its antitumor efficacy.Keywords: antioxidants, colorectal cancer, tumor models, metastasis

  18. A Salmonella Typhimurium outbreak linked to Vietnamese bread rolls in South Western Sydney, Australia, 2015.

    Science.gov (United States)

    Chandra, Meena; Lord, Heidi; Fletcher-Lartey, Stephanie; Alexander, Kate; Egana, Nilva; Conaty, Stephen

    2017-01-01

    In September 2015, the South Western Sydney (SWS) Public Health Unit was notified of a cluster of Salmonella Typhimurium (STm) cases with a common multiple-locus variable-number tandem repeats analysis (MLVA) pattern. An investigation was conducted to identify a source and contain the outbreak. The cluster was initially identified through routine geographic information system cluster scanning applied to the New South Wales Notifiable Conditions Management System. Additional cases were identified through a complaint to local council about a bakery. The bakery was inspected and 48 environmental and food swabs were collected for analysis. A total of 26 suspected cases were identified, of which 14 were interviewed. STm MLVA type 3-16-9-11-523 was identified in 19 of 26 case stool specimens. Most cases (12/14) consumed bread rolls containing pork or chicken with chicken liver pâté and raw egg mayonnaise filling. Five cases identified a common bakery exposure. Environmental and food samples from the bakery isolated STm with an identical MLVA pattern. An STm cluster in SWS was investigated and found to be linked to Vietnamese bread rolls containing pork or chicken with chicken liver pâté and raw egg mayonnaise filling. Confirmation of a distinct MLVA pattern among STm isolates from clinical, food and environmental samples provided evidence to establish an epidemiological link between the cases and the implicated premises and informed public health action to contain the outbreak.

  19. A Salmonella Typhimurium outbreak linked to Vietnamese bread rolls in South Western Sydney, Australia, 2015

    Directory of Open Access Journals (Sweden)

    Meena Chandra

    2017-06-01

    Full Text Available Introduction: In September 2015, the South Western Sydney (SWS Public Health Unit was notified of a cluster of Salmonella Typhimurium (STm cases with a common multiple-locus variable-number tandem repeats analysis (MLVA pattern. An investigation was conducted to identify a source and contain the outbreak. Methods: The cluster was initially identified through routine geographic information system cluster scanning applied to the New South Wales Notifiable Conditions Management System. Additional cases were identified through a complaint to local council about a bakery. The bakery was inspected and 48 environmental and food swabs were collected for analysis. Results: A total of 26 suspected cases were identified, of which 14 were interviewed. STm MLVA type 3-16-9-11-523 was identified in 19 of 26 case stool specimens. Most cases (12/14 consumed bread rolls containing pork or chicken with chicken liver pâté and raw egg mayonnaise filling. Five cases identified a common bakery exposure. Environmental and food samples from the bakery isolated STm with an identical MLVA pattern. Discussion: An STm cluster in SWS was investigated and found to be linked to Vietnamese bread rolls containing pork or chicken with chicken liver pâté and raw egg mayonnaise filling. Confirmation of a distinct MLVA pattern among STm isolates from clinical, food and environmental samples provided evidence to establish an epidemiological link between the cases and the implicated premises and informed public health action to contain the outbreak.

  20. Increasing Incidence of Salmonella in Australia, 2000-2013

    Science.gov (United States)

    Glass, Kathryn; Veitch, Mark; Wardell, Rebecca; Polkinghorne, Ben; Dobbins, Timothy; Lal, Aparna; Kirk, Martyn D.

    2016-01-01

    Salmonella is a key cause of foodborne gastroenteritis in Australia and case numbers are increasing. We used negative binomial regression to analyze national surveillance data for 2000–2013, for Salmonella Typhimurium and non-Typhimurium Salmonella serovars. We estimated incidence rate ratios adjusted for sex and age to show trends over time. Almost all states and territories had significantly increasing trends of reported infection for S. Typhimurium, with states and territories reporting annual increases as high as 12% (95% confidence interval 10–14%) for S. Typhimurium in the Australian Capital Territory and 6% (95% CI 5–7%) for non-Typhimurium Salmonella in Victoria. S. Typhimurium notification rates were higher than non-Typhimurium Salmonella rates in most age groups in the south eastern states of Australia, while non-Typhimurium rates were higher in most age groups elsewhere. The S. Typhimurium notification rate peaked at 12–23 months of age and the non-Typhimurium Salmonella notification rate peaked at 0–11 months of age. The age-specific pattern of S. Typhimurium cases suggests a foodborne origin, while the age and geographic pattern for non-Typhimurium may indicate that other transmission routes play a key role for these serovars. PMID:27732615

  1. Avaliação clínica da infecção experimental de bezerros com Salmonella Typhimurium

    Directory of Open Access Journals (Sweden)

    L.G. Ávila

    2011-12-01

    Full Text Available The clinical conditions of healthy calves infected with 10(9 CFU of Salmonella Typhimurium were evaluated and the viability of the experimental model in disease induction was verified. Twelve male Holstein calves, 10 to 15-days old, were examined. They were allocated into two groups, control and experimentally infected. Animals were submitted to clinical examination after inoculation and at every 24 hours, during six days after infection. Samples of rectal swabs were collected for Salmonella Typhimurium isolation. Results showed that all animals had different degrees of diarrhea, with mucus and bleeding, 24 to 72 hours after experimental infection with Salmonella Typhimurium, accompanied by fever, but no signs of sepsis. The isolation of Salmonella Typhimurium from rectal swabs occurred 24 hours after the infection and there were no deaths during the experiment, which means that this sorovar has an epidemiological importance related to the intermitent or continuous elimination of the bacterium. Results also showed that the oral administration of 10(9 CFU of Salmonella Typhimurium induces clinical signs of salmonellosis in 10 to 15-day-old calves.

  2. Increased efficacy of inactivated vaccine candidates prepared with Salmonella enterica serovar Typhimurium strains of predominant genotypes in ducks.

    Science.gov (United States)

    Youn, S Y; Kwon, Y K; Song, C S; Lee, H J; Jeong, O M; Choi, B K; Jung, S C; Kang, M S

    2016-08-01

    Salmonella enterica serovar Typhimurium has been a major causative agent of food-borne human disease, mainly due to consumption of contaminated food animal products. In particular, ducks serve as a reservoir of serovar Typhimurium, and are one of the common sources of human infection. To prevent infection of ducks, and therefore minimize human infection, it is critical to control the persistent epidemic strains in ducks. Here, we analyzed the genetic diversity and virulence of serovar Typhimurium isolates from ducks in Korea to identify the predominant strains that might be used as efficient vaccine candidates for ducks. Among the isolates, 2 representative isolates (ST26 and ST76) of predominant genotypes were selected as vaccine strains on the basis of genotypic analysis by pulsed-field gel electrophoresis and DNA microarrays. Two-week-old ducks were then injected intramuscularly with inactivated vaccine candidates prepared using ST26 or ST76 (10(8) cfu/0.5 mL/duck or 10(9) cfu/0.5 mL/duck), and oral challenge with a highly virulent serovar Typhimurium strain (10(9) cfu/0.5 mL/duck) was carried out 2 wk later. Shedding of the challenge strain was significantly decreased in group 2 after vaccination. The antibody levels by enzyme-linked immunosorbent assay in all vaccinated groups were enhanced significantly (P < 0.05) compared to the unvaccinated control group. Overall, vaccination with ST26 or ST76 reduced bacterial shedding and colonization in internal organs, and induced elevated antibody response. In particular, serovar Typhimurium ST26 (10(8) cfu/0.5 mL/duck) was the most effective vaccine candidate, which can provide efficient protection against serovar Typhimurium in ducks with higher effectiveness compared to a commercial vaccine currently used worldwide. © 2016 Poultry Science Association Inc.

  3. Drying parameters greatly affect the destruction of Cronobacter sakazakii and Salmonella Typhimurium in standard buffer and milk.

    Science.gov (United States)

    Lang, Emilie; Iaconelli, Cyril; Zoz, Fiona; Guyot, Stéphane; Alvarez-Martin, Pablo; Beney, Laurent; Perrier-Cornet, Jean-Marie; Gervais, Patrick

    2017-04-01

    Salmonella Typhimurium and Cronobacter sakazakii are two foodborne pathogens involved in neonatal infections from milk powder and infant formula. Their ability to survive in low-moisture food and during processing from the decontamination to the dried state is a major issue in food protection. In this work, we studied the effects of the drying process on Salmonella Typhimurium and Cronobacter sakazakii, with the aim of identifying the drying parameters that could promote greater inactivation of these two foodborne pathogens. These two bacteria were dried under different atmospheric relative humidities in milk and phosphate-buffered saline, and the delays in growth recovery and cultivability were followed. We found that water activity was related to microorganism resistance. C. sakazakii was more resistant to drying than was S. Typhimurium, and milk increased the cultivability and recovery of these two species. High drying rates and low final water activity levels (0.11-0.58) had a strong negative effect on the growth recovery and cultivability of these species. In conclusion, we suggest that effective use of drying processes may provide a complementary tool for food decontamination and food safety during the production of low-moisture foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Comparing TiO2 photocatalysis and UV-C radiation for inactivation and mutant formation of Salmonella typhimurium TA102.

    Science.gov (United States)

    Fiorentino, Antonino; Rizzo, Luigi; Guilloteau, Hélène; Bellanger, Xavier; Merlin, Christophe

    2017-01-01

    Salmonellosis is one of the most common causes of foodborne bacterial human disease worldwide, and the emergence of multidrug-resistant (MDR) strains of Salmonella enterica serovar Typhimurium (S. typhimurium) was associated to the incidence of invasive salmonellosis. The objective of the present work was to investigate the effects of the TiO2 photocatalysis process in terms of both bacteria inactivation and the emergence of mutants, on S. typhimurium TA102 water suspensions. The TiO2 photocatalysis was compared with a conventional disinfection process such as UV-C radiation. In spite of the faster bacterial inactivation obtained in UV-C disinfection experiments (45, 15, and 10 min for total inactivation for initial cell density 109, 108, and 107 CFU mL-1, respectively), photocatalytic disinfection (60, 30, and 15 min) was more energy efficient because of a lower energy requirement (2-20 mWs cm-2) compared to the UV-C disinfection process (5-30 mWs cm-2). During the photocatalytic experiments, the mutation frequency increased up to 1648-fold compared to background level for a 108 CFU mL-1 initial bacterial density, and mutants were inactivated after 1-10-min treatment, depending on initial bacterial cell density. In UV-C disinfection experiments, the mutation frequency increased up to 2181-fold for a 108 CFU mL-1 initial bacterial cell density, and UV-C doses in the range of 0.5-4.8 mWs cm-2 were necessary to decrease mutation frequency. In conclusion, both disinfection processes were effective in the inactivation of S. typhimurium cells, and mutants released into the environment can be avoided if cells are effectively inactivated.

  5. The addition of charcoals to broiler diets did not alter the recovery of Salmonella Typhimurium during grow-out.

    Science.gov (United States)

    Wilson, K M; Bourassa, D V; Davis, A J; Freeman, M E; Buhr, R J

    2016-03-01

    Two experiments evaluated prebiotics added to feed on the recovery of Salmonella in broilers during grow-out and processing. In Experiment 1, "seeder" chicks were inoculated with Salmonella Typhimurium and placed with penmates. Treatments were: basal control diet, added 0.3% bamboo charcoal, 0.6% bamboo charcoal, or 0.12% Aromabiotic (medium chain fatty acids). The ceca from seeders and penmates were sampled to confirm Salmonella colonization at 3, 4, and 6 wk, and pen litter was sampled weekly. At 3 wk, charcoal fed chicks had significantly lower cecal recovery (37% lower) of Salmonella via direct plating but no differences at wk 4 or 6. At 6 wk, broilers fed Aromabiotic had no recovery of Salmonella from ceca with direct plating and significantly, 18%, lower recovery with enrichment. In Experiment 2, the treatments were: basal control diet, added 0.3% bamboo charcoal, 0.3% activated bamboo charcoal, or 0.3% pine charcoal. At placement, 2 seeders were challenged with Salmonella and commingled with penmates and ceca sampled at 1 and 2 wk, and ceca from 5 penmates/pen at 3 to 6 wk. Weekly, the pH of the crop and duodenum was measured from 1 penmate/pen and the litter surface sampled. At the end of grow-out broilers were processed. Results showed that penmates had colonized at 1 and 2 wk. Cecal Salmonella showed no differences except at 4 wk, when activated bamboo charcoal had a 18% lower recovery of Salmonella (enrichment) compared to the control (88%). Similar to Experiment 1, the recovery of Salmonella from the litter was not significantly different among treatments, however an overall decrease in recovery by 4 wk with direct plating reoccurred. The pH of the duodenum and the crop were not different among treatments. Crop pH (6.0) for all treatments were significantly higher at wk 1 compared to wk 2 to 6. Charcoals had minimal effect on Salmonella recovery in the ceca, but following defeathering, broilers fed charcoals had significantly lower Salmonella

  6. Antagonistic and protective effects against Salmonella enterica serovar typhimurium by Lactobacillus murinus in the digestive tract of gnotobiotic mice Efeitos antagonista e protetor contra Salmonella enterica sorovar Typhimurium por Lactobacillus murinus no trato digestivo de camundongos gnotobióticos

    Directory of Open Access Journals (Sweden)

    Ana Luiza Sampaio Vasconcelos

    2003-11-01

    Full Text Available In the present study, production of antagonistic substances by Lactobacillus murinus against enteropathogenic bacteria was evaluated in vivo as well as a possible protective effect against an oral challenge with Salmonella Typhimurium using a gnotobiotic animal model. A higher mean survival time (P No presente estudo, a produção de substâncias antagonistas por Lactobacillus murinus contra bactérias enteropatogênicas foi avaliada in vivo assim como um possível efeito protetor contra um desafio oral com Salmonella Typhimurium utilizando um modelo animal gnotobiótico. Um maior tempo médio de sobrevida (P < 0,05 foi observado nos animais associados com L. murinus (7,89 ± 3,83 dias quando comparado com os controles (4,44 ± 0,73 dias. Lactobacillus murinus exerceu um potente efeito antagonista in vivo contra S. sonnei e com menos intensidade contra S. Typhimurium como revelado pelos halos de inibição ao redor das fezes dos animais associados com L. murinus. Os diâmetros dos halos de inibição ao redor dos conteúdos intestinais aumentaram ao longo do trato digestivo, seguindo proporcionalmente os níveis populacionais de L. murinus nas respectivas porções intestinais. Concluindo, o presente estudo mostra que a associação com L. murinus em camundongos gnotobióticos retarda a morte após um desafio oral com S. Typhimurium e que compostos inibitórios difusíveis obtidos em ensaios in vitro foram também produzidos in vivo e podem ser responsáveis por este efeito.

  7. Predictive model for survival and growth of Salmonella typhimurium DT104 on chicken skin during temperature abuse.

    Science.gov (United States)

    Oscar, T P

    2009-02-01

    To better predict risk of Salmonella infection from chicken subjected to temperature abuse, a study was undertaken to develop a predictive model for survival and growth of Salmonella Typhimurium DT104 on chicken skin with native flora. For model development, chicken skin portions (2.14 cm2) were inoculated with 0.85 log of Salmonella Typhimurium DT104 (ATCC 700408) and then stored at 5 to 50 degrees C for 8 h. Kinetic data from the storage trials were fit to a primary model to determine lag time (lamda), specific growth rate (micrro), and the 95% prediction interval (PI). Secondary models for lamda, mu, and PI as a function of storage temperature were developed and then combined with the primary model to create a tertiary model. Performance of the tertiary model was evaluated against dependent data, independent data for interpolation, and independent data for extrapolation to kosher chicken skin by using an acceptable prediction zone from -1 (fail-safe) to 0.5 (fail-dangerous) log per skin portion. Survival of Salmonella Typhimurium DT104 on chicken skin was observed during 8 h of storage at 5 to 20 degrees C and at 50 degrees C, whereas growth was observed from 25 to 45 degrees C and was optimal at 40 degrees C with a lamda of 2.5 h and a mu of 1.1 log/h. Variation of pathogen growth, as assessed by PI, increased in a nonlinear manner as a function of temperature and was greater for growth conditions than no-growth conditions. The percentage of acceptable prediction errors was 82.6% for dependent data, 83.7% for independent data for interpolation, and 81.6% for independent data for extrapolation to kosher skin, which all exceeded the performance criterion of 70% acceptable predictions. Thus, it was concluded that the tertiary model provided valid predictions for survival and growth of Salmonella Typhimurium DT104 from a low initial dose on both nonkosher and kosher chicken skin with native flora.

  8. Antibacterial activity of Ziziphora clinopodioides essential oil and nisin against Bacillus subtilis and Salmonella Typhimurium in commercial barley soup

    Directory of Open Access Journals (Sweden)

    Y. Shahbazi

    2017-03-01

    Full Text Available The objective of the current study was to evaluate the antibacterial activity of nisin (250 and 500 IU/mL, Ziziphora clinopodioides essential oil (0.1 and 0.2% and their combination against Bacillus subtilis and Salmonella Typhimurium in commercial barley soup during refrigerated storage. Based on our findings, the population of pathogens was reduced with the addition of the essential oil and nisin, increased concentration of the added antibacterial agents and the longer storage time of commercial barley soup. The group treated with the essential oil at 0.2% and nisin at 500 IU/mL showed the most rapid decrease in the number of S. Typhimurium and B. subtilis. By the end of seven and five days, populations of S. Typhimurium and B. subtilis in overall concentrations of the essential oil with nisin were totally inhibited, respectively. Our findings suggest the possibility of utilising commercial barley soup with a mixture of Z. clinopodioides essential oil and nisin for the reduction of B. subtilis and S. Typhimurium.

  9. Effects of irradiation and fumaric acid treatment on the inactivation of Listeria monocytogenes and Salmonella typhimurium inoculated on sliced ham

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hyeon-Jeong; Lee, Ji-Hye [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Song, Kyung Bin, E-mail: kbsong@cnu.ac.kr [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2011-11-15

    To examine the effects of fumaric acid and electron beam irradiation on the inactivation of foodborne pathogens in ready-to-eat meat products, sliced ham was inoculated with Listeria monocytogenes and Salmonella typhimurium. The inoculated ham slices were treated with 0.5% fumaric acid or electron beam irradiation at 2 kGy. Fumaric acid treatment reduced the populations of L. monocytogenes and S. typhimurium by approximately 1 log CFU/g compared to control populations. In contrast, electron beam irradiation decreased the populations of S. typhimurium and L. monocytogenes by 3.78 and 2.42 log CFU/g, respectively. These results suggest that electron beam irradiation is a better and appropriate technique for improving the microbial safety of sliced ham. - Highlights: > We compare irradiation and fumaric acid treatment on the inactivation of pathogens. > We examine changes in the populations of L. monocytogenes and S. typhimurium. > Irradiation at 2 kGy is more effective in sliced ham than fumaric acid treatment. > Low-dose irradiation can improve the microbial safety of sliced ham during storage.

  10. Biofilm Removal and Antimicrobial Activities of Agar Hydrogel Containing Colloid Nano-Silver against Staphylococcus aureus and Salmonella typhimurium

    Directory of Open Access Journals (Sweden)

    Leyla Sadat Bouryabaf

    2017-10-01

    Full Text Available Background:    Antibacterial and biofilm removal effects of agar hydrogel incorporating silver nanoparticles (SNP at various concentrations were studied against Staphylococcus aureus and Salmonella typhimurium in vitro.Methods:      The minimum inhibitory concentrations (MIC of SNP was determined by agar dilution method. Then, hydrogels were prepared by mixing of 0.5% w/v agar and SNP (1/2 MIC, MIC, and 2 MIC and their inhibitory efficacies against planktonic and biofilm forms of bacteria were measured using agar spot and microtiter test, respectively.Results:    The MIC value was 125 µg/ mL for both bacteria. All SNP hydrogels represented antibacterial activity against Staphylococcus aureus and S. typhimurium on agar culture, which was significant compared to control group (silver sulfadiazine cream. The developed biofilm of S. aureus and S. typhimurium were strongly (85% reduction and modernly affected (60% reduction by SNP hydrogels during 15 min contact time, respectively. A dose-dependent biofilm reduction was not demonstrated when different SNP concentrations were tested. Moreover, the results from this study confirmed the moderate sanitizing ability of SNP loaded hydrogel against planktonic forms of both bacteria, which SNP (2MIC hydrogel decreased only 2.3 log10 CFU/ mL in a primary population of S. typhimurium during 15 min exposure time.Conclusion:     We recommended SNP incorporated agar hydrogel as an effective biofilm removal sanitizer.

  11. The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance, blood profiles, intestinal Salmonella concentration, noxious gas emission, organ weight and breast meat quality of broiler challenged with Salmonella typhimurium.

    Science.gov (United States)

    Park, J H; Kim, I H

    2015-04-01

    An experiment was conducted to evaluate the effects of B. subtilis RX7 and B. subtilis B2A on growth performance, blood profiles, intestinal Salmonella population, noxious gas emission, organ weight and breast meat quality of broilers under S. typhimurium challenge. A total of 120, one-day-old Ross 308 male broiler chicks were assigned to four dietary treatments, composed of six replications, with five birds per replication, for 10 day. The dietary treatment groups were negative control (NC; no antibiotic, no B. subtilis), positive control (PC; NC + 0.1% virginiamycin), B. subtilis RX7 (NC + 0.1% B. subtilis RX7 1.0 × 10(9) cfu/g) and B. subtilis B2A (NC + 0.1% B. subtilis 1.0 × 10(9) cfu/g). All birds were orally challenged with 2 ml suspension, containing 10(4) cfu/ml of S. typhimurium KCCM 40253. Results indicated that the body weight gain, feed intake and feed conversion did not differ, among all comparative treatments. Serum haptoglobin concentration was lower in Bacillus treatments (RX7 + B2A) than the NC treatment (p meat after being stored for 1 day, under stress caused by the S. typhimurium challenge. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  12. Expression of antimicrobial peptides in cecal tonsils of chickens treated with probiotics and infected with Salmonella enterica serovar typhimurium.

    Science.gov (United States)

    Akbari, Mohammad Reza; Haghighi, Hamid Reza; Chambers, James R; Brisbin, Jennifer; Read, Leah R; Sharif, Shayan

    2008-11-01

    Several strategies currently exist for control of Salmonella enterica serovar Typhimurium colonization in the chicken intestine, among which the use of probiotics is of note. Little is known about the underlying mechanisms of probiotic-mediated reduction of Salmonella colonization. In this study, we asked whether the effect of probiotics is mediated by antimicrobial peptides, including avian beta-defensins (also called gallinacins) and cathelicidins. Four treatment groups were included in this study: a negative-control group, a probiotic-treated group, a Salmonella-infected group, and a probiotic-treated and Salmonella-infected group. On days 1, 3, and 5 postinfection (p.i.), the cecal tonsils were removed, and RNA was extracted and used for measurement of avian beta-defensin 1 (AvBD1), AvBD2, AvBD4, AvBD6, and cathelicidin gene expression by real-time PCR. The expressions of all avian beta-defensins and cathelicidin were detectable in all groups, irrespective of treatment and time point. Probiotic treatment and Salmonella infection did not affect the expression of any of the investigated genes on day 1 p.i. Furthermore, probiotic treatment had no significant effect on the expression of the genes at either 3 or 5 days p.i. However, the expression levels of all five genes were significantly increased (P probiotics eliminated the effect of Salmonella infection on the expression of antimicrobial genes. These findings indicate that the expression of antimicrobial peptides may be repressed by probiotics in combination with Salmonella infection or, alternatively, point to the possibility that, due to a reduction in Salmonella load in the intestine, these genes may not be induced.

  13. The Fur regulon in anaerobically grown Salmonella enterica sv. Typhimurium: identification of new Fur targets

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    Porwollik Steffen

    2011-10-01

    Full Text Available Abstract Background The Ferric uptake regulator (Fur is a transcriptional regulator that controls iron homeostasis in bacteria. Although the regulatory role of Fur in Escherichia coli is well characterized, most of the studies were conducted under routine culture conditions, i.e., in ambient oxygen concentration. To reveal potentially novel aspects of the Fur regulon in Salmonella enterica serovar Typhimurium under oxygen conditions similar to that encountered in the host, we compared the transcriptional profiles of the virulent wild-type strain (ATCC 14028s and its isogenic Δfur strain under anaerobic conditions. Results Microarray analysis of anaerobically grown Δfur S. Typhimurium identified 298 differentially expressed genes. Expression of several genes controlled by Fnr and NsrR appeared to be also dependent on Fur. Furthermore, Fur was required for the activity of the cytoplasmic superoxide disumutases (MnSOD and FeSOD. The regulation of FeSOD gene, sodB, occurred via small RNAs (i.e., the ryhB homologs, rfrA and rfrB with the aid of the RNA chaperone Hfq. The transcription of sodA was increased in Δfur; however, the enzyme was inactive due to the incorporation of iron instead of manganese in SodA. Additionally, in Δfur, the expression of the gene coding for the ferritin-like protein (ftnB was down-regulated, while the transcription of the gene coding for the nitric oxide (NO· detoxifying flavohemoglobin (hmpA was up-regulated. The promoters of ftnB and hmpA do not contain recognized Fur binding motifs, which indicated their probable indirect regulation by Fur. However, Fur activation of ftnB was independent of Fnr. In addition, the expression of the gene coding for the histone-like protein, H-NS (hns was increased in Δfur. This may explain the observed down-regulation of the tdc operon, responsible for the anaerobic degradation of threonine, and ftnB in Δfur. Conclusions This study determined that Fur is a positive factor in ftn

  14. Experimental Salmonella typhimurium infections in rats. II. Active and passive immunization as protection against a lethal bacterial dose

    DEFF Research Database (Denmark)

    Hougen, H P; Jensen, E T; Klausen, B

    1990-01-01

    Immunization against a lethal dose of Salmonella typhimurium was studied in athymic and thymus-bearing LEW rats. Active immunization was performed with formalin-killed whole cell vaccine or sublethal infection prior to the lethal infection. After vaccination with killed bacteria the euthymic...... animals produced antibodies against S.typhimurium, but neither the euthymic nor the athymic animals survived the infection. After non-lethal infection euthymic and thymus-grafted nude rats were not affected by the second and otherwise lethal bacterial dose, and had high antibody titres. All the athymic...... nude rats died after the second and lethal bacterial challenge. Passive immunization with plasma from immunized euthymic animals did not protect any of the animals against the lethal bacterial dose. However, all animals survived when treated with large doses of spleen cells from immunized euthymic rats...

  15. Antimicrobial activity of plant extracts against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes on fresh lettuce.

    Science.gov (United States)

    Kim, Sung-Youn; Kang, Dong-Hyun; Kim, Jin-Ki; Ha, Yong-Geun; Hwang, Ju Young; Kim, Taewan; Lee, Seon-Ho

    2011-01-01

    Plant extracts have been found to be effective in reducing microorganisms. This study evaluated antimicrobial activity of 12 plant extracts against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes by using a disk diffusion assay, and Syzygium aromaticum (clove) showed the highest inhibitory effect. To investigate the efficacy of clove extract that inactivates pathogens on lettuce, inoculated lettuce with S. Typhimurium, E. coli O157:H7, and L. monocytogenes was treated with diluted clove extracts or distilled water for 0, 1, 3, 5, and 10 min. Clove extract treatment significantly reduced populations of the 3 tested pathogens from the surface of lettuce. Practical Application: This result indicated that clove extract is a useful antimicrobial agent to reduce the microbial level of foodborne pathogens on fresh lettuce. It also might be a natural antimicrobial for reducing or replacing chemical sanitizers in food preservation.

  16. ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR SCREENING OF MILK SAMPLES FOR SALMONELLA-TYPHIMURIUM IN DAIRY HERDS

    DEFF Research Database (Denmark)

    Hoorfar, Jeffrey; Wedderkopp, A.

    1995-01-01

    We investigated the ability of an antibody-specific, O antigen-based ELISA to document Salmonella typhimurium herd infections by screening of milk samples. Three cattle populations, 20 herds with no history of salmonellosis, 8 herds with history of S typhimurium epsiodes within the previous 7...... months, and 220 herds of unknown disease status, were tested. A herd was considered ELISA positive if at least 5% of the cows had OD values > 0.3. Among the 20 herds without history of salmonellosis, only 2 herds were ELISA positive, whereas all 8 herds with a known history of salmonellosis were ELISA...... positive (herd specificity, 0.9 and herd sensitivity, 1.0). A sig nificant correlation (P salmonellosis. It was concluded that ELISA testing of individual milk sam ples can be used for surveillance...

  17. Presence and persistence of Salmonella enterica serotype typhimurium in the phyllosphere and rhizosphere of spray-irrigated parsley.

    Science.gov (United States)

    Kisluk, Guy; Yaron, Sima

    2012-06-01

    Salmonella enterica is one of the major food-borne pathogens associated with ready-to-eat fresh foods. Although polluted water might be a significant source of contamination in the field, factors that influence the transfer of Salmonella from water to the crops are not well understood, especially under conditions of low pathogen levels in water. The aim of this study was to investigate the short- and long-term (1 h to 28 days) persistence of Salmonella enterica serotype Typhimurium in the phyllosphere and the rhizosphere of parsley following spray irrigation with contaminated water. Plate counting and quantitative real-time PCR (qRT-PCR)-based methods were implemented for the quantification. By applying qRT-PCR with enrichment, we were able to show that even irrigation with water containing as little as ∼300 CFU/ml resulted in the persistence of S. Typhimurium on the plants for 48 h. Irrigation with water containing 8.5 log CFU/ml resulted in persistence of the bacteria in the phyllosphere and the rhizosphere for at least 4 weeks, but the population steadily declined with a major reduction in bacterial counts, of ∼2 log CFU/g, during the first 2 days. Higher levels of Salmonella were detected in the phyllosphere when plants were irrigated during the night compared to irrigation during the morning and during winter compared to the other seasons. Further elucidation of the mechanisms underlying the transfer of Salmonella from contaminated water to crops, as well as its persistence over time, will enable the implementation of effective irrigation and control strategies.

  18. Poultry Body Temperature Contributes to Invasion Control through Reduced Expression of Salmonella Pathogenicity Island 1 Genes in Salmonella enterica Serovars Typhimurium and Enteritidis

    Science.gov (United States)

    Petri, Nicholas; Daron, Caitlyn; Pereira, Rafaela; Mendoza, Mary; Hassan, Hosni M.; Koci, Matthew D.

    2015-01-01

    Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence. PMID:26386070

  19. The effect of phytogenic feed additives to substitute in-feed antibiotics on growth traits and blood biochemical parameters in broiler chicks challenged with Salmonella typhimurium.

    Science.gov (United States)

    Abudabos, Alaeldein M; Alyemni, Abdullah H; Dafalla, Yousif M; Khan, Rifat Ullah

    2016-12-01

    There is a growing concern over the use of antibiotics due to the increased resistance of pathogens in broiler. The present study was designed to find the comparative effect of an antibiotic, and some phytogenic on performance traits, blood biochemical parameters, and antioxidant status during starter phase exposed to Salmonella typhimurium challenge. A total of 560-day-old broiler chicks (Ross 308) were randomly allocated to seven treatments (eight replicates). Control (basal diet); T1, infected with Salmonella enterica subsp. typhimurium; T2, infected + avilamycin at the rate of 0.2 g/kg; T3, infected + essential oil of thymol; T4, infected + phytogenic; T5, infected + anti-Salmonella organic acid; and T6, infected + essential oils of thyme, anise, and other components. Body weight gain and feed conversion ratio (FCR) were significantly (P feed additives could be substituted with antibiotics in the feed of broiler exposed to S. typhimurium challenge.

  20. The Transcriptional Heat Shock Response of Salmonella Typhimurium Shows Hysteresis and Heated Cells Show Increased Resistance to Heat and Acid Stress

    DEFF Research Database (Denmark)

    Pin, C.; Hansen, Trine; Munoz-Cuevas, M.

    2012-01-01

    We investigated if the transcriptional response of Salmonella Typhimurium to temperature and acid variations was hysteretic, i.e. whether the transcriptional regulation caused by environmental stimuli showed memory and remained after the stimuli ceased. The transcriptional activity of non.......e., they remained up-regulated after the environmental stress ceased. At 25uC the transcriptional regulation of genes encoding for heat shock proteins was determined by the previous environment. Gene networks constructed with up-regulated genes were significantly more modular than those of down-regulated genes......H 4.5 were not affected. The exposure to pH 5 only caused up-regulation of 12 genes and this response was neither hysteretic nor accompanied of increased resistance to inactivation conditions. Cellular memory at the transcriptional level may represent a mechanism of adaptation to the environment...

  1. Acute gastroenterocolitis caused by Salmonella Chester

    Directory of Open Access Journals (Sweden)

    Tajda Keber

    2017-06-01

    Full Text Available Turtles are common as pets and represent a known reservoir for salmonellosis. There are few epidemic outbreaks of salmonellosis linked to ingestion of undercooked turtle meat described in the literature. A few cases of pet turtle borne infection and infection due to aquarium water contamination have been described. We present cases of two female patients hospitalized due to acute gastroenterocolitis caused by Salmonella Chester and the epidemiological report of events related to the infection outbreak. The infection was transmitted from the water of a private aquarium with two pet turtles.

  2. A biologically conjugated polysaccharide vaccine delivered by attenuated Salmonella Typhimurium provides protection against challenge of avian pathogenic Escherichia coli O1 infection.

    Science.gov (United States)

    Han, Yue; Liu, Qing; Yi, Jie; Liang, Kang; Wei, Yunan; Kong, Qingke

    2017-11-30

    Avian pathogenic Escherichia coli (APEC) causes avian airsacculitis and colibacillosis, resulting in significant economic loss to the poultry industry. O1, O2 and O78 are the three predominant serotypes. O-antigen of lipopolysaccharide is serotype determinant and highly immunogenic, and O-antigen polysaccharide-based vaccines have great potential for preventing bacterial infections. In this study, we utilized a novel yeast/bacterial shuttle vector pSS26 to clone the 10.8 kb operon synthesizing APEC O1 O-antigen polysaccharide. The resulting plasmid was introduced into attenuated Salmonella vaccines to deliver this O-antigen polysaccharide. O1 O-antigen was stably synthesized in attenuated Salmonella Typhimurium, demonstrated by slide agglutination, silver staining and western blot. Our results also showed that APEC O1 O-antigen produced in the Salmonella vaccines was attached to bacterial cell surfaces, and the presence of heterologous O-antigen did not alter the resistance to surface-acting agents. Furthermore, birds immunized orally or intramuscularly provided protection against the virulent O1 APEC challenge. Salmonella vaccines carrying APEC O1 O-antigen gene cluster also induced high IgG and IgA immune responses against lipopolysaccharide from the APEC O1 strain. The use of our novel shuttle vector facilitates cloning of large DNA fragments, and this strategy could pave the way for production of Salmonella-vectored vaccines against prevalent APEC serotypes. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Differential effects of rice bran cultivars to limit Salmonella Typhimurium in chicken cecal in vitro incubations and impact on the cecal microbiome and metabolome

    Science.gov (United States)

    Park, Si Hong; Roto, Stephanie M.; Nealon, Nora Jean; Ryan, Elizabeth P.

    2017-01-01

    In this study, rice brans from different cultivars (Calrose, Jasmine, and Red Wells) were assessed for their ability to inhibit Salmonella enterica serovar Typhimurium using an in vitro mixed anaerobic culture system containing cecal microbiota obtained from broilers of different ages. Salmonella Typhimurium was added to controls (feed only, cecal only, and feed + cecal material) and treatments (feed + cecal + different rice brans) and S. Typhimurium populations were enumerated at 0, 24, and 48 h. Two experimental conditions were applied 1) unadapted condition in which S. Typhimurium was added at the beginning of the culture incubation and 2) adapted condition in which S. Typhimurium was added after a 24 hour pre-incubation of the cecal bacteria with the feed and/or rice bran. Among the three rice brans, only Calrose exhibited a rapid inhibition of S. Typhimurium, which decreased to undetectable levels after 24 h under the adapted incubation. Changes in microbiological composition and metabolites by addition of Calrose bran were also investigated with an Illumina MiSeq platform and gas chromatography—mass spectrometry, respectively. Addition of Calrose bran resulted in significant changes including decreased Firmicutes phylum abundance and an increased number of metabolites associated with fatty acid metabolism. In summary, it appears that rice bran from specific rice cultivars may be effective as a means to reduce Salmonella in the chicken ceca. In addition, Calrose rice bran inclusion leads to changes in cecal microbiological composition and metabolite profile. PMID:28937988

  4. Hypophysectomy and Neurointermediate Pituitary Lobectomy Reduce Serum Immunoglobulin M (IgM) and IgG and Intestinal IgA Responses to Salmonella enterica Serovar Typhimurium Infection in Rats

    Science.gov (United States)

    Campos-Rodríguez, Rafael; Quintanar-Stephano, Andrés; Jarillo-Luna, Rosa Adriana; Oliver-Aguillón, Gabriela; Ventura-Juárez, Javier; Rivera-Aguilar, Victor; Berczi, Istvan; Kovacs, Kalman

    2006-01-01

    The influence of anterior pituitary hormones on the gastrointestinal tract of humans and animals has been reported. Hypophysectomy (HYPOX) in the rat causes atrophy of the intestinal mucosa, reduction of gastric secretion and intestinal absorption, and increased susceptibility to infections. To our knowledge, there are no studies on the humoral immune response of the gut-associated lymphoid tissue after HYPOX. We have reported that decreased secretion of vasopressin and oxytocin due to neurointermediate pituitary lobectomy (NIL) diminishes humoral and cell-mediated immune responses. However, no data have been published on whether NIL can affect intestinal immune responses. We analyzed the effects of HYPOX and NIL on bacterial colonization of the intestinal lumen, Peyer's patches, and spleen as well as the serum immunoglobulin G (IgG) and IgM and specific intestinal IgA levels in response to Salmonella enterica serovar Typhimurium oral infection. Results showed the following: (i) Salmonella serovar Typhimurium was eliminated from the intestinal lumen at the same rate in rats that underwent a sham operation, HYPOX, and NIL; (ii) Salmonella serovar Typhimurium colonization of Peyer's patches and spleen was significantly higher in both HYPOX and NIL rats than in sham-operated rats; (iii) serum IgG and IgM and intestinal IgA against surface proteins of Salmonella serovar Typhimurium were significantly lower in HYPOX and NIL rats than in sham-operated rats; and (iv) compared to NIL rats, higher Peyer's patch and spleen bacterial colonization and decreased IgG, IgM, and IgA production were observed in HYPOX rats. We conclude that hormones from each pituitary lobe affect the systemic and gastrointestinal humoral immune responses through different mechanisms. PMID:16495563

  5. Mutagenic and antimutagenic activities of Artemisia absinthium volatile oil by the bacterial reverse mutation assay in Salmonella typhimurium strains TA98 and TA100

    Directory of Open Access Journals (Sweden)

    Mahboubeh Taherkhani

    2014-09-01

    Full Text Available Objective: To investigate the mutagenic and antimutagenic activities of Artemisia absinthium L. (A. absinthium essential oil by the bacterial reverse mutation assay in Salmonella typhimurium (S. typhimurium strains. Methods: Water-distilled essential oil of A. absinthium collected from Ardabil, NorthWestern Iran, was investigated for mutagenic and antimutagenic activities. In present study, the mutagenic and antimutagenic activities of A. absinthium oil were investigated by the bacterial revere mutation assay in S. typhimurium TA98 and TA100 strains with and without S9 (microsomal mutagenesis assay. Results: The comparative mutagenicity effect was seen in 1.5 mg/plate by the bacterial reverse mutation assay in S. typhimurium TA98 strains, without S9 and the excellent antimutagenicity effect was seen in 1.5 mg/plate against S. typhimurium TA100, without S9. Conclusions: The mutagenicity and antimutagenicity effects of the volatile oil of A. absinthium were seen without the presence of metabolic activation.

  6. The role of ClpP, RpoS and CsrA in growth and filament formation of Salmonella enterica serovar Typhimurium at low temperature

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Nielsen, Maj-Britt; Thomsen, Line Elnif

    2014-01-01

    Background: Salmonellae are food-borne pathogens of great health and economic importance. To pose a threat to humans, Salmonellae normally have to cope with a series of stressful conditions in the food chain, including low temperature. In the current study, we evaluated the importance of the Clp...... proteolytic complex and the carbon starvation protein, CsrA, for the ability of Salmonella Typhimurium to grow at low temperature. Results: A clpP mutant was severely affected in growth and formed pin point colonies at 10 degrees C. Contrary to this, rpoS and clpP/rpoS mutants were only slightly affected....... The clpP mutant formed cold resistant suppressor mutants at a frequency of 2.5 x 10(-3) and these were found not to express RpoS. Together these results indicated that the impaired growth of the clpP mutant was caused by high level of RpoS. Evaluation by microscopy of the clpP mutant revealed...

  7. Reporters for Single-Cell Analysis of Colicin Ib Expression in Salmonella enterica Serovar Typhimurium.

    Directory of Open Access Journals (Sweden)

    Stefanie Spriewald

    Full Text Available Colicins are toxins that mediate interference competition in microbial ecosystems. They serve as a "common good" for the entire producer population but are synthesized by only few members which pay the costs of colicin production. We have previously shown that production of colicin Ib (cib, a group B colicin, confers a competitive advantage to Salmonella enterica serovar Typhimurium (S. Tm over commensal E. coli strains. Here, we studied regulation of S. Tm cib expression at the single cell level. Comparative analysis of a single- and a multicopy gfp-reporter for the colicin Ib promoter (Pcib revealed that the latter yielded optimal signal intensity for a diverse range of applications. We further validated this reporter and showed that gfp expression correlated well with colicin Ib (ColIb protein levels in individual cells. Pcib is negatively controlled by two repressors, LexA and Fur. Only a small fraction of S. Tm expressed cib under non-inducing conditions. We studied Pcib activity in response to mitomycin C mediated DNA damage and iron limitation. Both conditions, if applied individually, lead to an increase in the fraction of GFP+ S. Tm, albeit an overall low fluorescence intensity. When both conditions were applied simultaneously, the majority of S. Tm turned GFP+ and displayed high fluorescence intensity. Thus, both repressors individually confine cib expression to a subset of the population. Taken together, we provide the first thorough characterization of a conventional gfp-reporter to study regulation of a group B colicin at the single cell level. This reporter will be useful to further investigate the costs and benefits of ColIb production in human pathogenic S. Tm and analyze cib expression under environmental conditions encountered in the mammalian gut.

  8. Antibodies against Marinobacter algicola and Salmonella typhimurium flagellins do not cross-neutralize TLR5 activation.

    Directory of Open Access Journals (Sweden)

    Raul Terron-Exposito

    Full Text Available Flagellins evoke strong innate and adaptive immune responses. These proteins may play a key role as radioprotectors, exert antitumoral activity in certain types of tumor and reduce graft-versus-host disease in allogeneic hematopoietic stem cell transplant recipients. Notwithstanding, flagellins are highly immunogenic, and repeated use leads to their neutralization by systemic antibodies. This neutralization is not prevented by using functional deleted flagellins. These observations led us to explore the possibility of preventing initial neutralization by means of another functional flagellin that does not belong to common pathogenic bacteria but that has the capacity to activate TLR5. Here we characterized the functional capacity of the two-phase Marinobacter algicola (MA-derived flagellins (F and FR as systemic and mucosal adjuvants and compared their performance with that of Salmonella typhimurium (STF flagellins (FljB and FliC. We also report for the first time on the in vitro and in vivo capacity of various flagellins to trigger TLR5 activation in the presence of species-specific anti-flagellin antibodies, the cross-neutralization mediated by these antibodies, and the sequential use of these flagellins for TLR5 activation. Our results showed that MA flagellins behave in a similar way to STF ones, inducing pro-inflammatory cytokines (IL8, CCL20, CCL2 and evoking a strong in vivo antibody response against a model epitope. More importantly, MA flagellins were fully functional, in vitro or in vivo, in the presence of a high concentration of neutralizing anti-flagellin STF antibodies, and STF flagellin was not inhibited by neutralizing anti-flagellin MA antibodies. The use of active flagellins from distinct bacteria could be a useful approach to prevent systemic neutralization of this group of adjuvants and to facilitate the rational design of flagellin-based vaccines and/or other therapeutic treatments (against ischemia, acute renal failure

  9. An outbreak of Salmonella Typhimurium infections in Denmark, Norway and Sweden, 2008.

    Science.gov (United States)

    Bruun, T; Sørensen, G; Forshell, L P; Jensen, T; Nygard, K; Kapperud, G; Lindstedt, B A; Berglund, T; Wingstrand, A; Petersen, R F; Müller, L; Kjelsø, C; Ivarsson, S; Hjertqvist, M; Löfdahl, S; Ethelberg, S

    2009-03-12

    In November-December 2008, Norway and Denmark independently identified outbreaks of Salmonella Typhimurium infections characterised in the multiple-locus variable number of tandem repeats analysis (MLVA) by a distinct profile. Outbreak investigations were initiated independently in the two countries. In Denmark, a total of 37 cases were identified, and multiple findings of the outbreak strain in pork and pigs within the same supply chain led to the identification of pork in various forms as the source. In Norway, ten cases were identified, and the outbreak investigation quickly indicated meat bought in Sweden as the probable source and the Swedish authorities were alerted. Investigations in Sweden identified four human cases and two isolates from minced meat with the distinct profile. Subsequent trace-back of the meat showed that it most likely originated from Denmark. Through international alert from Norway on 19 December, it became clear that the Danish and Norwegian outbreak strains were identical and, later on, that the source of the outbreaks in all three countries could be traced back to Danish pork. MLVA was instrumental in linking the outbreaks in the different countries and tracing the source. This outbreak illustrates that good international communication channels, early alerting mechanisms, inter-sectoral collaboration between public health and food safety authorities and harmonised molecular typing tools are important for effective identification and management of cross-border outbreaks. Differences in legal requirements for food safety in neighbouring countries may be a challenge in terms of communication with consumers in areas where cross-border shopping is common.

  10. Effect of lipopolysaccharide mutations on recipient ability of Salmonella typhimurium for incompatibility group H plasmids.

    Science.gov (United States)

    Sherburne, C; Taylor, D E

    1997-01-01

    Previous investigations of the incompatibility group F, P, and I plasmid systems revealed the important role of the outer membrane components in the conjugal transfer of these plasmids. We have observed variability in transfer frequency of three incompatibility group H plasmids (IncHI1 plasmid R27, IncHI2 plasmid R478, and a Tn7 derivative of R27, pDT2454) upon transfer into various Salmonella typhimurium lipopolysaccharide (LPS) mutants derived from a common parental strain, SL1027. Recipients with truncated outer core via the rfaF LPS mutation increased the transfer frequency of the IncH plasmids by up to a factor of 10(3). Mutations which resulted in the truncation of the residues following 3-deoxy-D-manno-octulosonic acid, such as the rfaE and rfaD mutations, decreased the transfer frequency to undetectable levels. Addition of phosphorylethanolamine, a component of wild-type LPS, to the media decreased the frequency of transfer of R27 into wild-type and rfaF LPS mutant recipients tested. Reversing the direction of transfer, by mating LPS mutant donors with wild-type recipients, did not affect the frequency of transfer compared to the standard matings of wild-type donor with LPS mutant recipient. These findings demonstrate that conjugation interactions affected by LPS mutation are not specific for the recipient cell. Our results suggest that LPS mutation does not affect conjugation via altered pilus binding but affects some later steps in the conjugative process, and alteration of transfer frequency by O-phosphorylethanolamine and LPS truncation is due to charge-related interactions between the donor and recipient cell. PMID:9006054

  11. Structural and mutational studies on substrate specificity and catalysis of Salmonella typhimurium D-cysteine desulfhydrase.

    Directory of Open Access Journals (Sweden)

    Sakshibeedu R Bharath

    Full Text Available Salmonella typhimurium DCyD (StDCyD is a fold type II pyridoxal 5' phosphate (PLP-dependent enzyme that catalyzes the degradation of D-Cys to H(2S and pyruvate. It also efficiently degrades β-chloro-D-alanine (βCDA. D-Ser is a poor substrate while the enzyme is inactive with respect to L-Ser and 1-amino-1-carboxy cyclopropane (ACC. Here, we report the X-ray crystal structures of StDCyD and of crystals obtained in the presence of D-Cys, βCDA, ACC, D-Ser, L-Ser, D-cycloserine (DCS and L-cycloserine (LCS at resolutions ranging from 1.7 to 2.6 Å. The polypeptide fold of StDCyD consisting of a small domain (residues 48-161 and a large domain (residues 1-47 and 162-328 resembles other fold type II PLP dependent enzymes. The structures obtained in the presence of D-Cys and βCDA show the product, pyruvate, bound at a site 4.0-6.0 Å away from the active site. ACC forms an external aldimine complex while D- and L-Ser bind non-covalently suggesting that the reaction with these ligands is arrested at Cα proton abstraction and transimination steps, respectively. In the active site of StDCyD cocrystallized with DCS or LCS, electron density for a pyridoxamine phosphate (PMP was observed. Crystals soaked in cocktail containing these ligands show density for PLP-cycloserine. Spectroscopic observations also suggest formation of PMP by the hydrolysis of cycloserines. Mutational studies suggest that Ser78 and Gln77 are key determinants of enzyme specificity and the phenolate of Tyr287 is responsible for Cα proton abstraction from D-Cys. Based on these studies, a probable mechanism for the degradation of D-Cys by StDCyD is proposed.

  12. Mutagenicity of red wine in the L-arabinose resistance test with Salmonella typhimurium.

    Science.gov (United States)

    Dorado, G; Ariza, R R; Pueyo, C

    1988-11-01

    The forward mutation assay to L-arabinose resistance (Ara test) in Salmonella typhimurium detected a Spanish red table wine (Rioja) as a direct-acting mutagen. The best mutagenic response was obtained by preincubating strain BA13 with the wine sample in the presence of sodium phosphate buffer and in the absence of any external metabolic activation. In fact, the S9 mixture abolished most of the mutagenic activity of red wine in the Ara test. Such an inactivating capacity seems to be independent of microsomal enzymes and mediated through some kind of heat-stable component(s) in the S9 fraction. Both regular wine (directly from the bottle) and lyophilized wine were strong mutagens in the Ara test, inducing 4914 and 2739 AraR mutants/ml. Both pKM101 and delta uvrB were critical factors in the detection of the mutagenicity of wine, exhibiting a synergic effect in strain BA13. The mutagenicity of red wine was somehow pH-dependent, increasing with the pH value of the preincubation mixture. In comparison with the Ara test, the His reverse mutation assay (Ames test) was much less sensitive to the mutagenicity of lyophilized red wine, TA102 being the most (448 His+/ml) and TA98 the least (38 His+/ml) sensitive strain. TA100, TA104 and TA97 manifested intermediate mutagenicities to red wine. Previous reports have identified strain TA98 as the His strain most sensitive to the apolar fraction (e.g. XAD-2-bound) of red wine. Based on these results we propose that TA98 mainly detects glycosides of mutagenic flavonols present in red wine (quercetin, rutin, etc.), which do not constitute the major direct-acting mutagens detected with the Ara test.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Effects of Salmonella typhimurium Infection and Ofloxacin Treatment on Glucose and Glutamine Metabolism in Caco-2/TC-7 Cells

    OpenAIRE

    Posho, Leta; Delbos-Bocage, Laurence; Gueylard, Delphine; Farinotti, Robert; Carbon, Claude

    1998-01-01

    The effects of both Salmonella typhimurium infection and 5 mM ofloxacin treatment on 2 mM glutamine and 5 mM glucose metabolism in the enterocyte-like Caco-2/TC-7 cell line were studied. These cells utilized glutamine (212.07 ± 16.75 [mean ± standard deviation] nmol per h per 106 viable cells) and, to a lesser extent, glucose (139.63 ± 11.52 nmol per h per 106 viable cells). Metabolism of these substrates in Caco-2/TC-7 cells resembled that in rat, pig, or human enterocytes. Infection by S. t...

  14. Outbreak of Salmonella enterica serovar Typhimurium in Switzerland, May-June 2008, implications for production and control of meat preparations.

    Science.gov (United States)

    Schmid, H; Hachler, H; Stephan, R; Baumgartner, A; Boubaker, K

    2008-10-30

    An increased number of Salmonella Typhimurium cases were reported in Switzerland between May and June 2008. Investigations involved 72 cases. Results of PFGE typing identified several outbreak strains, the dominating one present in 43 of the 72 isolates. Strains affecting one third of the cases were also found in animal samples, in particular pork. However, no specific food source could be identified. Outbreaks described in this paper highlight the importance of food safety regulations such as those on minced meat and meat preparations issued by the European Commission and adopted by Switzerland into the national law.

  15. Generalised linear mixed models analysis of risk factors for contamination of Danish broiler flocks with Salmonella typhimurium

    DEFF Research Database (Denmark)

    Chriél, Mariann; Stryhn, H.; Dauphin, G.

    1999-01-01

    We present a retrospective observational study of risk factors associated with the occurrence of Salmonella typhimurium (ST) in Danish broiler flocks. The study is based on recordings from 1994 in the ante-mortem database maintained by the Danish Poultry Council. The epidemiological units...... and software for the analysis of a moderately-sized data set of veterinary origin. We compare the results from five analyses of the generalised linear mixed model (GLMM) type. The first observation is that the results agree reasonably well and lead to similar conclusions. A closer look reveals certain patterns...

  16. Spectra of spontaneous frameshift mutations at the hisD3052 allele of Salmonella typhimurium in four DNA repair backgrounds.

    OpenAIRE

    DeMarini, D M; Shelton, M L; Abu-Shakra, A; Szakmary, A; Levine, J. G.

    1998-01-01

    To characterize the hisD3052 -1 frameshift allele of Salmonella typhimurium, we analyzed approximately 6000 spontaneous revertants (rev) for a 2-base deletion hotspot within the sequence (CG)4, and we sequenced approximately 500 nonhotspot rev. The reversion target is a minimum of 76 bases (nucleotides 843-918) that code for amino acids within a nonconserved region of the histidinol dehydrogenase protein. Only 0.4-3.9% were true rev. Of the following classes, 182 unique second-site mutations ...

  17. Identification of Metabolic Pathways Essential for Fitness of Salmonella Typhimurium In Vivo

    DEFF Research Database (Denmark)

    Jelsbak, Lotte; Hartman, Hassan; Schroll, Casper

    2014-01-01

    Bacterial infections remain a threat to human and animal health worldwide, and there is an urgent need to find novel targets for intervention. In the current study we used a computer model of the metabolic network of Salmonella enterica serovar Typhimurium and identified pairs of reactions (cut...... in vitro but was attenuated during infection showing that polyamines are essential for virulence apparently in a growth independent manner. The serA/glyA cut-set was found to be growth attenuated as predicted by the model. However, not only the double mutant, but also the glyA mutant, were found...

  18. Microencapsulated sorbic acid and pure botanicals affect Salmonella Typhimurium shedding in pigs: a close-up look from weaning to slaughter in controlled and field conditions.

    Science.gov (United States)

    Grilli, Ester; Foresti, Fabio; Tugnoli, Benedetta; Fustini, Mattia; Zanoni, Maria G; Pasquali, Paolo; Callaway, Todd R; Piva, Andrea; Alborali, Giovanni L

    2015-10-01

    The aim of this study was to assess the efficacy of a combination of sorbic acid, thymol, and carvacrol in reducing the prevalence and shedding level of Salmonella Typhimurium in pigs either in a controlled challenge environment or in a production setting. In the first study, 24 weaned piglets were separated in 4 isolation units (6 piglets/isolation unit). Each unit received either a basal diet (no treatment) or a microencapsulated mixture of sorbic acid, thymol, and carvacrol at 1, 2, or 5 g/kg of feed. After 21 d, pigs were orally challenged with 6 log10 colony-forming units of Salmonella Typhimurium. Blood samples and feces from rectal ampullae were collected every week. On d56 of the study, pigs were euthanized and necropsied to collect intestinal contents (jejunum through colon) and ileocecal lymph nodes. Samples were analyzed for Salmonella Typhimurium and serological analysis was also conducted. In the second study, an all-in-all-out multisite pig farm that was positive for monophasic Salmonella Typhimurium was followed throughout a production cycle from weaning to slaughter. Pigs received either a basal diet or the basal diet including 5 g/kg of the microencapsulated additive. Environmental, fecal, and blood samples were collected monthly, and cecal contents and ileocecal lymph nodes were collected at slaughter to isolate and enumerate Salmonella. The results indicate that the additive at 5 g/kg tended to reduce Salmonella fecal prevalence in both a controlled challenge (p=0.07) and in production conditions (p=0.03). Nevertheless, the additive did not reduce the number of pigs seropositive for Salmonella, nor it reduced the Salmonella prevalence at slaughter. The data indicate that these additives are not effective alone but must be used in conjunction with appropriate containment measures at lairage in order to prevent reinfection in pigs and to reduce the number of pigs carrying Salmonella entering the food chain.

  19. Epidemics of invasive Salmonella enterica serovar enteritidis and S. enterica Serovar typhimurium infection associated with multidrug resistance among adults and children in Malawi.

    Science.gov (United States)

    Gordon, Melita A; Graham, Stephen M; Walsh, Amanda L; Wilson, Lorna; Phiri, Amos; Molyneux, Elizabeth; Zijlstra, Eduard E; Heyderman, Robert S; Hart, C Anthony; Molyneux, Malcolm E

    2008-04-01

    Nontyphoidal salmonellae (NTS) have become the most common cause of bacteremia in tropical Africa, particularly among susceptible children and HIV-infected adults. We describe 4956 episodes of NTS bacteremia (2439 episodes in adults and 2517 episodes in children) that occurred in Blantyre, Malawi, during the 7-year period 1998-2004. A total of 75% of the cases of NTS bacteremia were due to Salmonella enterica serovar Typhimurium, and 21% were due to S. enterica serovar Enteritidis. Epidemic increases in the incidence of NTS bacteremia were seen sequentially, occurring first among cases caused by S. Enteritidis and then among cases caused by S. Typhimurium. Increased incidence of bacteremia was temporally associated with the acquisition of multidrug resistance to ampicillin, cotrimoxazole, and chloramphenicol by each serovar and occurred while the incidence of infection due to other common bloodstream pathogens remained constant. These epidemics were observed among adults and children. A seasonal pattern was also seen, with increased incidence during and after the rainy season. The median age of the patients was 32 years among adults and 22 months among children. Acquisition of multidrug-resistant infection was not associated with an increased case-fatality rate among children (22%), and the case-fatality rate among adults showed a significant trend toward decreasing (from 29% to 20%). These data have important implications for the treatment of severe febrile illness in adults and children in tropical Africa. Further understanding of the molecular basis of these epidemics of multidrug-resistant NTS infection, including ongoing whole-genome sequencing of multidrug-resistant isolates, will yield important tools for the study of NTS pathogenesis, transmission, epidemiology, and prevention.

  20. Effect of irradiation on kinetic behavior of Salmonella Typhimurium and Staphylococcus aureus in lettuce and damage of bacterial cell envelope

    Science.gov (United States)

    Shim, Won-Bo; Je, Gil-Soo; Kim, Kyeongyeol; Mtenga, Adelard B.; Lee, Won-Gyeong; Song, Jeong-Un; Chung, Duck-Hwa; Yoon, Yohan

    2012-05-01

    This study evaluated effect of gamma irradiation on survival of Salmonella Typhimurium and Staphylococcus aureus on lettuce and damage of cell envelope. S. Typhimurium and S. aureus were inoculated on red leaf lettuce, and they were irradiated at 0, 0.5, 1, 1.5, 2, 2.5, and 3 kGy, and the samples were then stored at 7 and 25 °C for 7 days. Survival of S. Typhimurium and S. aureus were enumerated on xylose lysine deoxycholate agar and Baird-Parker agar, respectively. D10 value (dose required to reduce 1 log CFU/leaf) was calculated, and kinetic parameters (maximum specific growth rate; μmax and lag phase duration; LPD) were calculated by the modified Gompertz model. In addition, cell envelope damage of the pathogens was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). D10 values were 0.35 and 0.33 kGy for S. Typhimurium and S. aureus, respectively. During storage at 7 °C, S. Typhimurium and S. aureus had significant (P<0.05) growth only on non-irradiated samples up to about 2.5 and 4 log CFU/leaf at 0.42 and 1.28 log CFU/leaf/day of μmax, respectively. At 25 °C, cell counts of S. Typhimurium and S. aureus on the samples irradiated at 0 and 0.5 kGy increased (P<0.05) up to 3-6 log CFU/leaf. The μmax of both pathogens were higher in 0 kGy (1.08-2.27 log CFU/leaf/day) and 0.5 kGy (0.58-0.92 log CFU/leaf/day), and LPDs ranged from 1.53 to 3.14 day. SEM and TEM observations showed that cells irradiated at 1.5 and 3 kGy showed disrupted cell membrane. These results indicate that gamma irradiation could be a useful decontamination technology to improve food safety of lettuce by destroying cells of S. Typhimurium and S. aureus.

  1. Characteristics of Salmonella enterica serovar 4,[5],12:i:- as a monophasic variant of serovar Typhimurium.

    Directory of Open Access Journals (Sweden)

    Noriko Ido

    Full Text Available Salmonella enterica subspecies enterica serovar 4,[5],12:i:- (S. 4,[5]12:i:- is believed to be a monophasic variant of S. enterica serovar Typhimurium (S. Typhimurium. This study was conducted to corroborate this hypothesis and to identify the molecular and phenotypic characteristics of the S. 4,[5]12:i:- isolates in Japan. A total of 51 S. 4,[5]12:i:- isolates derived from humans, cattle, swine, chickens, birds, meat (pork, and river water in 15 prefectures in Japan between 2000 and 2010 were analyzed. All the S. 4,[5],12:i:- isolates were identified as S. Typhimurium by two different polymerase chain reactions (PCR for identification of S. Typhimurium. Of the 51 S. 4,[5],12:i:- isolates, 39 (76.5% harbored a 94-kb virulence plasmid, which is known to be specific for S. Typhimurium. These data suggest that the S. 4,[5],12:i:- isolates are monophasic variants of S. Typhimurium. The flagellar phase variation is induced by three adjacent genes (fljA, fljB, and hin in the chromosome. The results of PCR mapping of this region and comparative genomic hybridiza