scholarly journals Salmonella enterica Serovar Enteritidis Pathogenicity Island 1 Is Not Essential for but Facilitates Rapid Systemic Spread in Chickens

2009 ◽  
Vol 77 (7) ◽  
pp. 2866-2875 ◽  
Author(s):  
Taseen S. Desin ◽  
Po-King S. Lam ◽  
Birgit Koch ◽  
Claudia Mickael ◽  
Emil Berberov ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Systemic Infection ◽  
Poultry Meat ◽  
Wild Type ◽  
Secretion Systems ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Systemic Spread ◽  
Mutant Strains ◽  
Vitro Analysis

ABSTRACT Salmonella enterica subsp. enterica serovar Enteritidis is a leading cause of human food-borne illness that is mainly associated with the consumption of contaminated poultry meat and eggs. To cause infection, S. Enteritidis is known to use two type III secretion systems, which are encoded on two salmonella pathogenicity islands, SPI-1 and SPI-2, the first of which is thought to play a major role in invasion and bacterial uptake. In order to study the role of SPI-1 in the colonization of chicken, we constructed deletion mutants affecting the complete SPI-1 region (40 kb) and the invG gene. Both ΔSPI-1 and ΔinvG mutant strains were impaired in the secretion of SipD, a SPI-1 effector protein. In vitro analysis using polarized human intestinal epithelial cells (Caco-2) revealed that both mutant strains were less invasive than the wild-type strain. A similar observation was made when chicken cecal and small intestinal explants were coinfected with the wild-type and ΔSPI-1 mutant strains. Oral challenge of 1-week-old chicken with the wild-type or ΔSPI-1 strains demonstrated that there was no difference in chicken cecal colonization. However, systemic infection of the liver and spleen was delayed in birds that were challenged with the ΔSPI-1 strain. These data demonstrate that SPI-1 facilitates systemic infection but is not essential for invasion and systemic spread of the organism in chickens.

scholarly journals Salmonella enterica Serovar Enteritidis tatB and tatC Mutants Are Impaired in Caco-2 Cell Invasion In Vitro and Show Reduced Systemic Spread in Chickens

2010 ◽  
Vol 78 (8) ◽  
pp. 3493-3505 ◽  
Author(s):  
Claudia Silva Mickael ◽  
Po-King S. Lam ◽  
Emil M. Berberov ◽  
Brenda Allan ◽  
Andrew A. Potter ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Sodium Dodecyl ◽  
Systemic Infection ◽  
Poultry Meat ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Systemic Spread ◽  
Essential Components ◽  
Tat System ◽  
Folded Proteins

ABSTRACT Salmonella enterica subsp. enterica serovar Enteritidis is a leading causative agent of gastroenteritis in humans. This pathogen also colonizes the intestinal tracts of poultry and can spread systemically in chickens. Transfer to humans usually occurs through undercooked or improperly handled poultry meat or eggs. The bacterial twin-arginine transport (Tat) pathway is responsible for the translocation of folded proteins across the cytoplasmic membrane. In order to study the role of the Tat system in the infection and colonization of chickens by Salmonella Enteritidis, we constructed chromosomal deletion mutants of the tatB and tatC genes, which are essential components of the Tat translocon. We observed that the tat mutations affected bacterial cell morphology, motility, and sensitivity to albomycin, sodium dodecyl sulfate (SDS), and EDTA. In addition, the mutant strains showed reduced invasion of polarized Caco-2 cells. The wild-type phenotype was restored in all our Salmonella Enteritidis tat mutants by introducing episomal copies of the tatABC genes. When tested in chickens by use of a Salmonella Enteritidis ΔtatB strain, the Tat system inactivation did not substantially affect cecal colonization, but it delayed systemic infection. Taken together, our data demonstrated that the Tat system plays a role in Salmonella Enteritidis pathogenesis.

scholarly journals Single passage in mouse organs enhances the survival and spread of Salmonella enterica

2015 ◽  
Vol 12 (113) ◽  
pp. 20150702 ◽  
Author(s):  
Richard Dybowski ◽  
Olivier Restif ◽  
Alexandre Goupy ◽  
Duncan J. Maskell ◽  
Piero Mastroeni ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Probability Generating Function ◽  
Systemic Infection ◽  
Original Method ◽  
Wild Type ◽  
Immigration Process ◽  
Serovar Typhimurium ◽  
Intravenous Inoculation

Intravenous inoculation of Salmonella enterica serovar Typhimurium into mice is a prime experimental model of invasive salmonellosis. The use of wild-type isogenic tagged strains (WITS) in this system has revealed that bacteria undergo independent bottlenecks in the liver and spleen before establishing a systemic infection. We recently showed that those bacteria that survived the bottleneck exhibited enhanced growth when transferred to naive mice. In this study, we set out to disentangle the components of this in vivo adaptation by inoculating mice with WITS grown either in vitro or in vivo . We developed an original method to estimate the replication and killing rates of bacteria from experimental data, which involved solving the probability-generating function of a non-homogeneous birth–death–immigration process. This revealed a low initial mortality in bacteria obtained from a donor animal. Next, an analysis of WITS distributions in the livers and spleens of recipient animals indicated that in vivo -passaged bacteria started spreading between organs earlier than in vitro -grown bacteria. These results further our understanding of the influence of passage in a host on the fitness and virulence of Salmonella enterica and represent an advance in the power of investigation on the patterns and mechanisms of host–pathogen interactions.

scholarly journals The Chemokine CCL2 Is Required for Control of Murine Gastric Salmonella enterica Infection

2005 ◽  
Vol 73 (10) ◽  
pp. 6514-6522 ◽  
Author(s):  
R. William DePaolo ◽  
Rashida Lathan ◽  
Barrett J. Rollins ◽  
William J. Karpus
Keyword(s):  
Typhoid Fever ◽  
Salmonella Enterica ◽  
Critical Factor ◽  
Wild Type ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Vitro Analysis ◽  
In Vitro Analysis

ABSTRACT Salmonella enterica is a gram-negative intracellular pathogen that can cause a variety of diseases ranging from gastroenteritis to typhoid fever. The Typhimurium serotype causes gastroenteritis in humans; however, infection of mice results in an enteric fever that resembles human typhoid fever and has been used as a model for typhoid fever. The present study examined the role of the chemokine CCL2 in the control of Salmonella infection. Upon infection with salmonellae, mucosal expression of CCL2 is rapidly up-regulated, followed by systemic expression in the spleen. CCL2−/− mice became moribund earlier and had a higher rate of mortality compared to wild-type C57BL/6 mice. Moreover, CCL2−/− mice had significantly higher levels of bacteria in the liver compared to wild-type controls. Mucosal and serum interleukin-6 and tumor necrosis factor alpha levels were elevated in CCL2−/− mice compared to wild-type mice. In vitro analysis demonstrated that CCL2−/− macrophages infected with salmonellae resulted in dysregulated cytokine production compared to macrophages derived from wild-type mice. These data are the first to directly demonstrate CCL2 as a critical factor for immune responses and survival following S. enterica infection.

Protection of epithelial cells from Salmonella enterica serovar Enteritidis invasion by antibodies against the SPI-1 type III secretion system

2010 ◽  
Vol 56 (6) ◽  
pp. 522-526 ◽  
Author(s):  
Taseen S. Desin ◽  
Claudia S. Mickael ◽  
Po-King S. Lam ◽  
Andrew A. Potter ◽  
Wolfgang Köster
Keyword(s):  
Epithelial Cells ◽  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Secretion Systems ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Specific Antibodies ◽  
Type Iii ◽  
Food Borne Illness

Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is one of the major causes of bacterial food-borne illness in humans. During the course of infection, Salmonella Enteritidis uses 2 type III secretion systems (T3SS), one of which is encoded on Salmonella pathogenicity island 1 (SPI-1). SPI-1 plays a major role in the invasion process. In the present study, we evaluated the effect of sera against the SPI-1 T3SS components on invasion in vitro using polarized human intestinal epithelial cells (Caco-2). Antisera to SipD protected Caco-2 cells against entry of wild-type Salmonella Enteritidis. On the other hand, sera against InvG, PrgI, SipA, SipC, SopB, SopE, and SopE2 did not affect Salmonella Enteritidis entry. To illustrate the specificity of anti-SipD mediated inhibition, SipD-specific antibodies were depleted from the serum. Antiserum depleted of SipD-specific antibodies lost its capacity to inhibit Salmonella Enteritidis entry. Thus, we demonstrate for the first time that antibodies against the SPI-1 needle tip protein (SipD) inhibit Salmonella Enteritidis invasion and that the SipD protein may be an important target in blocking SPI-1 mediated virulence of Salmonella Enteritidis.

scholarly journals Pathogenic Role of SEF14, SEF17, and SEF21 Fimbriae in Salmonella enterica Serovar Enteritidis Infection of Chickens

2000 ◽  
Vol 66 (4) ◽  
pp. 1759-1763 ◽  
Author(s):  
Gireesh Rajashekara ◽  
Shirin Munir ◽  
Mikhail F. Alexeyev ◽  
David A. Halvorson ◽  
Carol L. Wells ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Wild Type ◽  
Macrophage Cell ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Fecal Shedding ◽  
Mutant Strains ◽  
Chicken Macrophage ◽  
Type Strains ◽  
Ht 29

ABSTRACT Very little is known about the contribution of surface appendages of Salmonella enterica serovar Enteritidis to pathogenesis in chickens. This study was designed to clarify the role of SEF14, SEF17, and SEF21 fimbriae in serovar Enteritidis pathogenesis. Stable, single, defined sefA (SEF14), agfA (SEF17), andfimA (SEF21) insertionally inactivated fimbrial gene mutants of serovar Enteritidis were constructed. All mutant strains invaded Caco-2 and HT-29 enterocytes at levels similar to that of the wild type. Both mutant and wild-type strains were ingested equally well by chicken macrophage cell lines HD11 and MQ-NCSU. There were no significant differences in the abilities of these strains to colonize chicken ceca. The SEF14− strain was isolated in lower numbers from the livers of infected chickens and was cleared from the spleens faster than other strains. No significant differences in fecal shedding of these strains were observed.

scholarly journals Subspecies IIIa and IIIb Salmonellae Are Defective for Colonization of Murine Models of Salmonellosis Compared to Salmonella enterica subsp. I Serovar Typhimurium

2009 ◽  
Vol 191 (8) ◽  
pp. 2843-2850 ◽  
Author(s):  
Erin Katribe ◽  
Lydia M. Bogomolnaya ◽  
Heather Wingert ◽  
Helene Andrews-Polymenis
Keyword(s):  
Salmonella Enterica ◽  
Murine Models ◽  
Secretion Systems ◽  
Phenotypic Differences ◽  
Type Iii Secretion Systems ◽  
Systemic Spread ◽  
Serovar Typhimurium ◽  
Sporadic Disease

ABSTRACT Non-subspecies I salmonellae are commensals of cold-blooded vertebrates and cause sporadic disease in mammals. The reasons why non-subspecies I salmonellae do not circulate in populations of warm-blooded vertebrates, but instead only cause occasional disease in this niche, are unknown. We examined the ability of Salmonella enterica subsp. IIIa (subsp. arizonae) and subsp. IIIb (subsp. diarizonae) isolates to grow competitively with subspecies I (serovar Typhimurium) ATCC 14028 in vitro, to colonize Salmonella-sensitive BALB/c mice, and to persist in the intestine of Salmonella-resistant CBA/J mice in competitive infections. Subspecies IIIa had severely reduced intestinal colonization, intestinal persistence, and systemic spread in mice. Subspecies IIIa is nonmotile on swarming agar and thus may also have reduced motility under viscous conditions in vivo. Surprisingly, subspecies IIIb colonizes the intestinal tract of BALB/c mice normally yet does not spread systemically. Subspecies IIIb colonization of the intestine of CBA/J mice is reduced late in infection. In order to understand why these isolates do not colonize systemic sites, we determined that subspecies IIIa and IIIb are not internalized well and do not replicate in J774-A.1 murine macrophages, despite normal adherence to these cells. We further show that selected effectors of both type III secretion systems 1 and 2 are secreted by subspecies IIIa and IIIb in vitro but that each of these isolates secretes a different combination of effectors. We outline the phenotypic differences between these subspecies and subspecies I and provide a possible explanation for the inability of these strains to spread systemically in murine models.

scholarly journals In vitro analysis of elongation and termination by mutant RNA polymerases with altered termination behavior.

1996 ◽  
Vol 16 (11) ◽  
pp. 6468-6476 ◽  
Author(s):  
S A Shaaban ◽  
E V Bobkova ◽  
D M Chudzik ◽  
B D Hall
Keyword(s):  
Rna Polymerase Iii ◽  
Multiple Roles ◽  
Wild Type ◽  
Protein Motifs ◽  
Study Support ◽  
Vitro Analysis ◽  
Pol Iii ◽  
In Vitro Analysis

We have studied the in vitro elongation and termination properties of several yeast RNA polymerase III (pol III) mutant enzymes that have altered in vivo termination behavior (S. A. Shaaban, B. M. Krupp, and B. D. Hall, Mol. Cell. Biol. 15:1467-1478, 1995). The pattern of completed-transcript release was also characterized for three of the mutant enzymes. The mutations studied occupy amino acid regions 300 to 325, 455 to 521, and 1061 to 1082 of the RET1 protein (P. James, S. Whelen, and B. D. Hall, J. Biol. Chem. 266:5616-5624, 1991), the second largest subunit of yeast RNA pol III. In general, mutant enzymes which have increased termination require a longer time to traverse a template gene than does wild-type pol III; the converse holds true for most decreased-termination mutants. One increased-termination mutant (K310T I324K) was faster and two reduced termination mutants (K512N and T455I E478K) were slower than the wild-type enzyme. In most cases, these changes in overall elongation kinetics can be accounted for by a correspondingly longer or shorter dwell time at pause sites within the SUP4 tRNA(Tyr) gene. Of the three mutants analyzed for RNA release, one (T455I) was similar to the wild type while the two others (T455I E478K and E478K) bound the completed SUP4 pre-tRNA more avidly. The results of this study support the view that termination is a multistep pathway in which several different regions of the RET1 protein are actively involved. Region 300 to 325 likely affects a step involved in RNA release, while the Rif homology region, amino acids 455 to 521, interacts with the nascent RNA 3' end. The dual effects of several mutations on both elongation kinetics and RNA release suggest that the protein motifs affected by them have multiple roles in the steps leading to transcription termination.

scholarly journals Virulence and Metabolic Characteristics of Salmonella enterica Serovar Enteritidis Strains with DifferentsefDVariants in Hens

2012 ◽  
Vol 78 (18) ◽  
pp. 6405-6412 ◽  
Author(s):  
Cesar A. Morales ◽  
Jean Guard ◽  
Roxana Sanchez-Ingunza ◽  
Devendra H. Shah ◽  
Mark Harrison
Keyword(s):  
Salmonella Enterica ◽  
Egg Production ◽  
The Body ◽  
Wild Type ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Blood Calcium ◽  
Content Type ◽  
Metabolic Characteristics ◽  
Wide Range ◽  
Metabolic Properties

ABSTRACTSalmonella entericaserovar Enteritidis is one of a fewSalmonella entericaserotypes that has SEF14 fimbriae encoded by thesefoperon, which consists of 4 cotranscribed genes,sefABCD, regulated bysefR. A parental strain was used to construct asefDmutant and its complement, and all 3 strains were compared for gene expression, metabolic properties, and virulence characteristics in hens. Transcription ofsefDby wild type was suppressed at 42°C and absent for the mutant under conditions where the complemented mutant had 103times higher transcription. Growth of the complemented mutant was restricted in comparison to that of the mutant and wild type. Hens infected with the wild type and mutant showed decreased blood calcium and egg production, but infection with the complemented mutant did not. Thus, the absence ofsefDcorrelated with increased metabolic capacity and enhanced virulence of the pathogen. These results suggest that any contribution thatsefDmakes to egg contamination is either unknown or would be limited to early transmission from the environment to the host. Absence ofsefD, either through mutation or by suppression of transcription at the body temperature of the host, may contribute to the virulence ofSalmonella entericaby facilitating growth on a wide range of metabolites.

scholarly journals Caveolin-1-Deficient Mice Show Defects in Innate Immunity and Inflammatory Immune Response during Salmonella enterica Serovar Typhimurium Infection

2006 ◽  
Vol 74 (12) ◽  
pp. 6665-6674 ◽  
Author(s):  
Freddy A. Medina ◽  
Cecilia J. de Almeida ◽  
Elliott Dew ◽  
Jiangwei Li ◽  
Gloria Bonuccelli ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Salmonella Enterica ◽  
Inflammatory Responses ◽  
Systemic Infection ◽  
Bacterial Invasion ◽  
Chemokine Production ◽  
Caveolin 1 ◽  
Serovar Typhimurium ◽  
Deficient Mice

ABSTRACT A number of studies have shown an association of pathogens with caveolae. To this date, however, there are no studies showing a role for caveolin-1 in modulating immune responses against pathogens. Interestingly, expression of caveolin-1 has been shown to occur in a regulated manner in immune cells in response to lipopolysaccharide (LPS). Here, we sought to determine the role of caveolin-1 (Cav-1) expression in Salmonella pathogenesis. Cav-1−/− mice displayed a significant decrease in survival when challenged with Salmonella enterica serovar Typhimurium. Spleen and tissue burdens were significantly higher in Cav-1−/− mice. However, infection of Cav-1−/− macrophages with serovar Typhimurium did not result in differences in bacterial invasion. In addition, Cav-1−/− mice displayed increased production of inflammatory cytokines, chemokines, and nitric oxide. Regardless of this, Cav-1−/− mice were unable to control the systemic infection of Salmonella. The increased chemokine production in Cav-1−/− mice resulted in greater infiltration of neutrophils into granulomas but did not alter the number of granulomas present. This was accompanied by increased necrosis in the liver. However, Cav-1−/− macrophages displayed increased inflammatory responses and increased nitric oxide production in vitro in response to Salmonella LPS. These results show that caveolin-1 plays a key role in regulating anti-inflammatory responses in macrophages. Taken together, these data suggest that the increased production of toxic mediators from macrophages lacking caveolin-1 is likely to be responsible for the marked susceptibility of caveolin-1-deficient mice to S. enterica serovar Typhimurium.

scholarly journals Potyviral 6K2 Protein Long-Distance Movement and Symptom-Induction Functions Are Independent and Host-Specific

2004 ◽  
Vol 17 (5) ◽  
pp. 502-510 ◽  
Author(s):  
Carl Spetz ◽  
Jari P. T. Valkonen
Keyword(s):  
Spontaneous Mutation ◽  
Systemic Infection ◽  
Wild Type ◽  
Virus Propagation ◽  
Long Distance ◽  
Potato Virus A ◽  
Viral Mutant ◽  
Membrane Bound ◽  
Long Distance Movement

Deletion of various portions, or insertion of six histidine residues (6×His) into various positions of the membrane-bound 6K2 protein (53 amino acids) of Potato virus A (PVA, genus Potyvirus), inhibited systemic infection in Nicotiana tabacum and N. benthamiana plants. However, a spontaneous mutation (Gly2Cys) that occurred in 6K2 adjacent to the 6×His insert placed between Ser1 and Gly2 enabled systemic infection in a single N. benthamiana plant. No symptoms were observed, but virus titers were similar to the symptom-inducing wild-type (wt) PVA. N. tabacum plants were not systemically infected, albeit virus propagation was observed in inoculated protoplasts. The 6×His/Gly2Cys mutant was reconstructed in vitro and serially propagated by mechanical inoculation in N. benthamiana. Following the third passage, a novel viral mutant appeared, lacking the last four His residues of the insert, as well as the Gly2 and Thr3 of 6K2. It infected N. tabacum plants systemically, and in the systemically infected N. benthamiana leaves, vein chlorosis and mild yellowing symptoms were observed, typical of wt PVA infection. The mutant virus accumulated to titers similar to wt PVA in both hosts. These results show that the PVA 6K2 protein affects viral long-distance movement and symptom induction independently and in a host-specific manner.

Sign in / Sign up

Export Citation Format

Share Document