scholarly journals Analysis of Host Cells Associated with the Spv-Mediated Increased Intracellular Growth Rate of Salmonella typhimurium in Mice

1998 ◽  
Vol 66 (6) ◽  
pp. 2471-2485 ◽  
Author(s):  
Paul A. Gulig ◽  
Thomas J. Doyle ◽  
Jeffrey A. Hughes ◽  
Hidenori Matsui
Keyword(s):  
Growth Rate ◽  
Salmonella Typhimurium ◽  
Wild Type Strain ◽  
Systemic Infection ◽  
Host Cells ◽  
Virulence Plasmid ◽  
Intracellular Growth ◽  
Primary Host ◽  
Oral Inoculation ◽  
Subcutaneous Inoculation

ABSTRACT The 90-kb virulence plasmid of Salmonella typhimuriumencodes five spv genes which increase the growth rate of the bacteria within host cells within the first week of systemic infection of mice (P. A. Gulig and T. J. Doyle, Infect. Immun. 61:504–511, 1993). The presently described study was aimed at identifying the host cells associated with Spv-mediated virulence by manipulating the mouse host and the salmonellae. To test the effects of T cells and B cells on the Spv phenotype, salmonellae were orally inoculated into nude and SCID BALB/c mice. Relative to normal BALB/c mice, nude and SCID BALB/c mice were unaffected for splenic infection with either the Spv+ or Spv− S. typhimurium strains at 5 days postinoculation. When mice were pretreated with cyclophosphamide to induce granulocytopenia, there was a variable increase in total salmonella infection, but the relative splenic CFU of Spv+ versus Spv− S. typhimurium was not changed after oral inoculation. In contrast, depletion of macrophages from mice by treatment with cyclophosphamide plus liposomes containing dichloromethylene diphosphate resulted in equivalent virulence of Spv+ and Spv−salmonellae. To examine if the spv genes affected the growth of salmonellae in nonphagocytic cells, aninvA::aphT mutation was transduced into Spv+ and Spv− S. typhimuriumstrains. InvA− Spv+ salmonellae were not significantly affected for splenic infection after subcutaneous inoculation compared with the wild-type strain, and InvA−Spv− salmonellae were only slightly attenuated relative to InvA+ Spv− salmonellae. Invasion-defective salmonellae still exhibited the Spv phenotype. Therefore, infection of nonphagocytes is not involved with the Spv virulence function. Taken together, these data demonstrate that macrophages are essential for suppressing the infection by Spv− S. typhimurium, by serving as the primary host cell for Spv-mediated intracellular replication and possibly by inhibiting the replication of salmonellae within other macrophages.

scholarly journals Virulence Plasmid-Borne spvB and spvC Genes Can Replace the 90-Kilobase Plasmid in Conferring Virulence to Salmonella enterica Serovar Typhimurium in Subcutaneously Inoculated Mice

2001 ◽  
Vol 183 (15) ◽  
pp. 4652-4658 ◽  
Author(s):  
Hidenori Matsui ◽  
Christopher M. Bacot ◽  
Wendy A. Garlington ◽  
Thomas J. Doyle ◽  
Steve Roberts ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Systemic Infection ◽  
Reticuloendothelial System ◽  
Host Cells ◽  
Virulence Plasmid ◽  
Replication Rate ◽  
Oral Inoculation ◽  
Low Copy Number ◽  
Serovar Typhimurium

ABSTRACT In a mouse model of systemic infection, the spv genes carried on the Salmonella enterica serovar Typhimurium virulence plasmid increase the replication rate of salmonellae in host cells of the reticuloendothelial system, most likely within macrophages. A nonpolar deletion in the spvB gene greatly decreased virulence but could not be complemented by spvBalone. However, a low-copy-number plasmid expressing spvBCfrom a constitutive lacUV5 promoter did complement thespvB deletion. By examining a series of spvmutations and cloned spv sequences, we deduced thatspvB and spvC could be sufficient to confer plasmid-mediated virulence to S. enterica serovar Typhimurium. The spvBC-bearing plasmid was capable of replacing all of the spv genes, as well as the entire virulence plasmid, of serovar Typhimurium for causing systemic infection in BALB/c mice after subcutaneous, but not oral, inoculation. A point mutation in the spvBC plasmid preventing translation but not transcription of spvC eliminated the ability of the plasmid to confer virulence. Therefore, it appears that both spvB and spvC encode the principal effector factors for Spv- and plasmid-mediated virulence of serovar Typhimurium.

The major PEP-phosphotransferase systems (PTSs) for glucose, mannose and cellobiose of Listeria monocytogenes, and their significance for extra- and intracellular growth

Microbiology ◽  
2010 ◽  
Vol 156 (4) ◽  
pp. 1069-1083 ◽  
Author(s):  
Regina Stoll ◽  
Werner Goebel
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Epithelial Cells ◽  
Type Strain ◽  
Minimal Medium ◽  
Wild Type Strain ◽  
Wild Type ◽  
Intracellular Growth ◽  
Sugar Alcohols ◽  
Genes Encoding

In this report we examine the PEP-dependent phosphotransferase systems (PTSs) of Listeria monocytogenes EGD-e, especially those involved in glucose and cellobiose transport. This L. monocytogenes strain possesses in total 86 pts genes, encoding 29 complete PTSs for the transport of carbohydrates and sugar alcohols, and several single PTS components, possibly supporting transport of these compounds. By a systematic deletion analysis we identified the major PTSs involved in glucose, mannose and cellobiose transport, when L. monocytogenes grows in a defined minimal medium in the presence of these carbohydrates. Whereas all four PTS permeases belonging to the PTSMan family may be involved in mannose transport, only two of these (PTSMan-2 and PTSMan-3), and in addition at least one (PTSGlc-1) of the five PTS permeases belonging to the PTSGlc family, are able to transport glucose, albeit with different efficiencies. Cellobiose is transported mainly by one (PTSLac-4) of the six members belonging to the PTSLac family. In addition, PTSGlc-1 appears to be also able to transport cellobiose. The transcription of the operons encoding PTSMan-2 and PTSLac-4 (but not that of the operon for PTSMan-3) is regulated by LevR-homologous PTS regulation domain (PRD) activators. Whereas the growth rate of the mutant lacking PTSMan-2, PTSMan-3 and PTSGlc-1 is drastically reduced (compared with the wild-type strain) in the presence of glucose, and that of the mutant lacking PTSLac-4 and PTSGlc-1 in the presence of cellobiose, replication of both mutants within epithelial cells or macrophages is as efficient as that of the wild-type strain.

scholarly journals Genome Expression Analysis of Nonproliferating Intracellular Salmonella enterica Serovar Typhimurium Unravels an Acid pH-Dependent PhoP-PhoQ Response Essential for Dormancy

2012 ◽  
Vol 81 (1) ◽  
pp. 154-165 ◽  
Author(s):  
Cristina Núñez-Hernández ◽  
Alberto Tierrez ◽  
Álvaro D. Ortega ◽  
M. Graciela Pucciarelli ◽  
Marta Godoy ◽  
...  
Keyword(s):  
Metabolic Reprogramming ◽  
Host Cells ◽  
Infection Model ◽  
Intracellular Bacteria ◽  
Virulence Plasmid ◽  
Intracellular Growth ◽  
Content Type ◽  
Serovar Typhimurium

Genome-wide expression analyses have provided clues on howSalmonellaproliferates inside cultured macrophages and epithelial cells. However,in vivostudies show thatSalmonelladoes not replicate massively within host cells, leaving the underlying mechanisms of such growth control largely undefined.In vitroinfection models based on fibroblasts or dendritic cells reveal limited proliferation of the pathogen, but it is presently unknown whether these phenomena reflect events occurringin vivo. Fibroblasts are distinctive, since they represent a nonphagocytic cell type in whichS. entericaserovar Typhimurium actively attenuates intracellular growth. Here, we show in the mouse model thatS. Typhimurium restrains intracellular growth within nonphagocytic cells positioned in the intestinal lamina propria. This response requires a functional PhoP-PhoQ system and is reproduced in primary fibroblasts isolated from the mouse intestine. The fibroblast infection model was exploited to generate transcriptome data, which revealed that ∼2% (98 genes) of theS. Typhimurium genome is differentially expressed in nongrowing intracellular bacteria. Changes include metabolic reprogramming to microaerophilic conditions, induction of virulence plasmid genes, upregulation of the pathogenicity islands SPI-1 and SPI-2, and shutdown of flagella production and chemotaxis. Comparison of relative protein levels of several PhoP-PhoQ-regulated functions (PagN, PagP, and VirK) in nongrowing intracellular bacteria and extracellular bacteria exposed to diverse PhoP-PhoQ-inducing signals denoted a regulation responding to acidic pH. These data demonstrate thatS. Typhimurium restrains intracellular growthin vivoand support a model in which dormant intracellular bacteria could sense vacuolar acidification to stimulate the PhoP-PhoQ system for preventing intracellular overgrowth.

Interaction between host cells and Salmonella Typhimurium isolates from septicemic pigs

2009 ◽  
Author(s):  
Nadia Bergeron ◽  
J. Corriveau ◽  
Ann Letellier ◽  
F. Daigle ◽  
L. Lessard ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Host Cells

scholarly journals Legionella pneumophila DotU and IcmF Are Required for Stability of the Dot/Icm Complex

2004 ◽  
Vol 72 (10) ◽  
pp. 5983-5992 ◽  
Author(s):  
Jessica A. Sexton ◽  
Jennifer L. Miller ◽  
Aki Yoneda ◽  
Thomas E. Kehl-Fie ◽  
Joseph P. Vogel
Keyword(s):  
Cell Surface ◽  
Legionella Pneumophila ◽  
Bacterial Species ◽  
Wide Distribution ◽  
Host Cells ◽  
Growth Defect ◽  
Intracellular Growth ◽  
Homologous Proteins ◽  
Type Iv ◽  
Cell Surface Structure

ABSTRACT Legionella pneumophila utilizes a type IV secretion system (T4SS) encoded by 26 dot/icm genes to replicate inside host cells and cause disease. In contrast to all other L. pneumophila dot/icm genes, dotU and icmF have homologs in a wide variety of gram-negative bacteria, none of which possess a T4SS. Instead, dotU and icmF orthologs are linked to a locus encoding a conserved cluster of proteins designated IcmF-associated homologous proteins, which has been proposed to constitute a novel cell surface structure. We show here that dotU is partially required for L. pneumophila intracellular growth, similar to the known requirement for icmF. In addition, we show that dotU and icmF are necessary for optimal plasmid transfer and sodium sensitivity, two additional phenotypes associated with a functional Dot/Icm complex. We found that these effects are due to the destabilization of the T4SS at the transition into the stationary phase, the point at which L. pneumophila becomes virulent. Specifically, three Dot proteins (DotH, DotG, and DotF) exhibit decreased stability in a ΔdotU ΔicmF strain. Furthermore, overexpression of just one of these proteins, DotH, is sufficient to suppress the intracellular growth defect of the ΔdotU ΔicmF mutant. This suggests a model where the DotU and IcmF proteins serve to prevent DotH degradation and therefore function to stabilize the L. pneumophila T4SS. Due to their wide distribution among bacterial species and their genetic linkage to known or predicted cell surface structures, we propose that this function in complex stabilization may be broadly conserved.

Detection of Virulence Plasmid–Encoded Genes in Salmonella Typhimurium and Salmonella Kentucky Isolates Recovered from Commercially Processed Chicken Carcasses

2019 ◽  
Vol 82 (8) ◽  
pp. 1364-1368 ◽  
Author(s):  
RIZWANA TASMIN ◽  
PAUL A. GULIG ◽  
SALINA PARVEEN
Keyword(s):  
United States ◽  
Salmonella Typhimurium ◽  
Virulence Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
The United States ◽  
Clinical Isolates ◽  
Virulence Plasmid ◽  
Chicken Carcass ◽  
Serovar Typhimurium ◽  
Salmonella Virulence

ABSTRACT Salmonella enterica serovar Typhimurium is one of the leading causes of nontyphoidal gastroenteritis of humans in the United States. Commercially processed poultry carcasses are frequently contaminated with Salmonella serovar Kentucky in the United States. The aim of the study was to detect the Salmonella virulence plasmid containing the spv genes from Salmonella isolates recovered from commercially processed chicken carcasses. A total of 144 Salmonella isolates (Salmonella Typhimurium, n = 72 and Salmonella Kentucky, n = 72) were used for isolation of plasmids and detection of corresponding virulence genes (spvA, spvB, and spvC). Only four (5.5%) Salmonella Typhimurium isolates tested positive for all three virulence genes and hence were classified as possessing the virulence plasmid. All isolates of Salmonella Kentucky were negative for the virulence plasmid and genes. These results indicate that the virulence plasmid, which is very common among clinical isolates of Typhimurium and other Salmonella serovars (e.g., Enteritidis, Dublin, Choleraesuis, Gallinarum, Pullorum, and Abortusovis), may not be present in a significant portion of commercially processed chicken carcass isolates.

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