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1.
Camila Valenzuela Magdalena Gil Ítalo M. Urrutia Andrea Sabag Jost Enninga Carlos A. Santiviago 《Cellular microbiology》2021,23(1)
The ability of Salmonella to survive and replicate within mammalian host cells involves the generation of a membranous compartment known as the Salmonella‐containing vacuole (SCV). Salmonella employs a number of effector proteins that are injected into host cells for SCV formation using its type‐3 secretion systems encoded in SPI‐1 and SPI‐2 (T3SS‐1 and T3SS‐2, respectively). Recently, we reported that S. Typhimurium requires T3SS‐1 and T3SS‐2 to survive in the model amoeba Dictyostelium discoideum. Despite these findings, the involved effector proteins have not been identified yet. Therefore, we evaluated the role of two major S. Typhimurium effectors SopB and SifA during D. discoideum intracellular niche formation. First, we established that S. Typhimurium resides in a vacuolar compartment within D. discoideum. Next, we isolated SCVs from amoebae infected with wild type or the ΔsopB and ΔsifA mutant strains of S. Typhimurium, and we characterised the composition of this compartment by quantitative proteomics. This comparative analysis suggests that S. Typhimurium requires SopB and SifA to modify the SCV proteome in order to generate a suitable intracellular niche in D. discoideum. Accordingly, we observed that SopB and SifA are needed for intracellular survival of S. Typhimurium in this organism. Thus, our results provide insight into the mechanisms employed by Salmonella to survive intracellularly in phagocytic amoebae. 相似文献
2.
Gad Frankel 《Cellular microbiology》2018,20(9)
Although nontyphoidal Salmonella (NTS; including Salmonella Typhimurium) mainly cause gastroenteritis, typhoidal serovars (Salmonella Typhi and Salmonella Paratyphi A) cause typhoid fever, the treatment of which is threatened by increasing drug resistance. Our understanding of S. Typhi infection in human remains poorly understood, likely due to the host restriction of typhoidal strains and the subsequent popularity of the S. Typhimurium mouse typhoid model. However, translating findings with S. Typhimurium across to S. Typhi has some limitations. Notably, S. Typhi has specific virulence factors, including typhoid toxin and Vi antigen, involved in symptom development and immune evasion, respectively. In addition to unique virulence factors, both typhoidal and NTS rely on two pathogenicity‐island encoded type III secretion systems (T3SS), the SPI‐1 and SPI‐2 T3SS, for invasion and intracellular replication. Marked differences have been observed in terms of T3SS regulation in response to bile, oxygen, and fever‐like temperatures. Moreover, approximately half of effectors found in S. Typhimurium are either absent or pseudogenes in S. Typhi, with most of the remaining exhibiting sequence variation. Typhoidal‐specific T3SS effectors have also been described. This review discusses what is known about the pathogenesis of typhoidal Salmonella with emphasis on unique behaviours and key differences when compared with S. Typhimurium. 相似文献
3.
Case report of clinical salmonellosis by Salmonella Typhimurium that occurred in Portuguese children
Aims: Aim of this study is to characterize clinical isolates of Salmonella Typhimurium that occurred in Portuguese children on the basis of their virulence and antimicrobial resistance profiles and pulsed‐field gel electrophoresis typing and to analyse possible strain relatedness. Methods and Results: Different Salmonella serotypes were isolated from clinical cases of salmonellosis that had occurred in two Portuguese hospitals (a total of 259 isolates). All Salm. Typhimurium strains, with the age of the patients known, (total of 26 isolates) were selected for this study. These isolates were characterized for their virulence gene profiles (agfA, iroB, slyA, hin/H2, spv), antimicrobial resistance profiles and investigated for the occurrence of multidrug‐resistant Salm. Typhimurium DT 104 by PCR. Salmonella isolates showed high rates of resistance to four or more antibiotics, 100% resistance to sulfadiazine and a high percentage of strains with the resistance profile of Salm. Typhimurium DT 104, two of them with this phage type (determined by PCR). A relationship between some clusters and their resistance and virulence profiles was detected, each cluster having the same profile. Conclusions: This study showed high‐antibiotic resistance of the Salmonella strains investigated, and the presence of multidrug‐resistant Salm. Typhimurium DT104 in infections of Portuguese children. Significance and Impact of the Study: Study is based on regarding the increase in antibiotic resistance by Salmonella strains isolated from infections in Portuguese children and on the presence of Salm. Typhimurium DT 104 circulating in Portugal. 相似文献
4.
Salmonella Typhimurium contains 13 operons coding for fimbriae with unique binding specificities to host epithelial surfaces. stj operon is only detected in S. Typhimurium genome suggesting that Stj fimbria may effect serovarspecific virulence characteristics. In this study, the
role of stj fimbrial operon in the long-term persistence of S. Typhimurium was identified by competitive infection experiment in genetically resistant mouse (CBA) model system. Knock-out
mutation of stjA (major subunit of the Stj fimbria) gene reduced recovery of S. Typhimurium from fecal samples and its colonization to spleen, cecum and mesenteric lymph nodes over a 34-day time period
(p < 0.05). This data indicate that stj fimbrial operon has a role in long-term intestinal persistence of S. Typhimurium in CBA mice. 相似文献
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6.
Pietro Calderini Marta Magi Simona Gabrielli Alberto Brozzi Susanna Kumlien Goffredo Grifoni Albertina Iori Gabriella Cancrini 《BMC veterinary research》2009,5(1):1-6
Background
Feed contaminated with Salmonella spp. constitutes a risk of Salmonella infections in animals, and subsequently in the consumers of animal products. Salmonella are occasionally isolated from the feed factory environment and some clones of Salmonella persist in the factory environment for several years. One hypothesis is that biofilm formation facilitates persistence by protecting bacteria against environmental stress, e.g. disinfection. The aim of this study was to investigate the biofilm forming potential of Salmonella strains from feed- and fishmeal factories. The study included 111 Salmonella strains isolated from Norwegian feed and fish meal factories in the period 1991–2006 of serovar Agona, serovar Montevideo, serovar Senftenberg and serovar Typhimurium. 相似文献7.
Chak Hon Luk Camila Valenzuela Magdalena Gil La Swistak Perrine Bomme Yuen-Yan Chang Adeline Mallet Jost Enninga 《PLoS pathogens》2021,17(4)
Salmonella Typhimurium (S. Typhimurium) is an enteric bacterium capable of invading a wide range of hosts, including rodents and humans. It targets different host cell types showing different intracellular lifestyles. S. Typhimurium colonizes different intracellular niches and is able to either actively divide at various rates or remain dormant to persist. A comprehensive tool to determine these distinct S. Typhimurium lifestyles remains lacking. Here we developed a novel fluorescent reporter, Salmonella INtracellular Analyzer (SINA), compatible for fluorescence microscopy and flow cytometry in single-bacterium level quantification. This identified a S. Typhimurium subpopulation in infected epithelial cells that exhibits a unique phenotype in comparison to the previously documented vacuolar or cytosolic S. Typhimurium. This subpopulation entered a dormant state in a vesicular compartment distinct from the conventional Salmonella-containing vacuoles (SCV) as well as the previously reported niche of dormant S. Typhimurium in macrophages. The dormant S. Typhimurium inside enterocytes were viable and expressed Salmonella Pathogenicity Island 2 (SPI-2) virulence factors at later time points. We found that the formation of these dormant S. Typhimurium is not triggered by the loss of SPI-2 effector secretion but it is regulated by (p)ppGpp-mediated stringent response through RelA and SpoT. We predict that intraepithelial dormant S. Typhimurium represents an important pathogen niche and provides an alternative strategy for S. Typhimurium pathogenicity and its persistence. 相似文献
8.
Background
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.Methodology/Principal Findings
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.Conclusions/Significance
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 [1]. 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. 相似文献9.
Hung-Chih Kuo Tsai-Ling Lauderdale Dan-Yuan Lo Chiou-Lin Chen Pei-Chen Chen Shiu-Yun Liang Jung-Che Kuo Ying-Shu Liao Chun-Hsing Liao Chi-Sen Tsao Chien-Shun Chiou 《PloS one》2014,9(4)
We collected 110 Salmonella enterica isolates from sick pigs and determined their serotypes, genotypes using pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility to 12 antimicrobials and compared the data with a collection of 18,280 isolates obtained from humans. The pig isolates fell into 12 common serovars for human salmonellosis in Taiwan; S. Typhimurium, S. Choleraesuis, S. Derby, S. Livingstone, and S. Schwarzengrund were the 5 most common serovars and accounted for a total of 84% of the collection. Of the 110 isolates, 106 (96%) were multidrug resistant (MDR) and 48 (44%) had PFGE patterns found in human isolates. S. Typhimurium, S. Choleraesuis, and S. Schwarzengrund were among the most highly resistant serovars. The majority of the 3 serovars were resistant to 8–11 of the tested antimicrobials. The isolates from pigs and humans sharing a common PFGE pattern displayed identical or very similar resistance patterns and Salmonella strains that caused severe infection in pigs were also capable of causing infections in humans. The results indicate that pigs are one of the major reservoirs to human salmonellosis in Taiwan. Almost all of the pig isolates were MDR, which highlights the necessity of strictly regulating the use of antimicrobials in the agriculture sector in Taiwan. 相似文献
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Girish Ramachandran Darren J. Perkins Patrick J. Schmidlein Mohan E. Tulapurkar Sharon M. Tennant 《PLoS neglected tropical diseases》2015,9(1)
Invasive non-typhoidal Salmonella (iNTS) are an important cause of septicemia in children under the age of five years in sub-Saharan Africa. A novel genotype of Salmonella enterica subsp. enterica serovar Typhimurium (multi-locus sequence type [ST] 313) circulating in this geographic region is genetically different to from S. Typhimurium ST19 strains that are common throughout the rest of the world. S. Typhimurium ST313 strains have acquired pseudogenes and genetic deletions and appear to be evolving to become more like the typhoidal serovars S. Typhi and S. Paratyphi A. Epidemiological and clinical data show that S. Typhimurium ST313 strains are clinically associated with invasive systemic disease (bacteremia, septicemia, meningitis) rather than with gastroenteritis. The current work summarizes investigations of the broad hypothesis that S. Typhimurium ST313 isolates from Mali, West Africa, will behave differently from ST19 isolates in various in vitro assays. Here, we show that strains of the ST313 genotype are phagocytosed more efficiently and are highly resistant to killing by macrophage cell lines and primary mouse and human macrophages compared to ST19 strains. S. Typhimurium ST313 strains survived and replicated within different macrophages. Infection of macrophages with S. Typhimurium ST19 strains resulted in increased apoptosis and higher production of proinflammatory cytokines, as measured by gene expression and protein production, compared to S. Typhimurium ST313 strains. This difference in proinflammatory cytokine production and cell death between S. Typhimurium ST19 and ST313 strains could be explained, in part, by an increased production of flagellin by ST19 strains. These observations provide further evidence that S. Typhimurium ST313 strains are phenotypically different to ST19 strains and instead share similar pathogenic characteristics with typhoidal Salmonella serovars. 相似文献
12.
Mechanisms of resistance to quinolones in Salmonella Typhimurium from patients with infectious diarrhea
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This study investigated the mechanisms of resistance of 36 quinolone‐resistant Salmonella Typhimurium strains isolated from outpatients with infectious diarrhea in Beijing Tian Tan Hospital between 2013 and 2015. The resistance spectrum of the 36 strains was measured using a broth dilution method. Class 1 integrons harboring the β‐lactamase gene and mutations in quinolone resistance determining regions were also investigated. All 36 quinolone‐resistant Salmonella Typhimurium strains were found to be multidrug‐resistant and the majority of these strains harbored Class 1 integrons. These findings study suggests that strategies for determining resistance spectrums should be implemented with greater urgency. 相似文献
13.
Sonia M. Hernandez Kevin Keel Susan Sanchez Eija Trees Peter Gerner-Smidt Jennifer K. Adams Ying Cheng Al Ray III Gordon Martin Andrea Presotto Mark G. Ruder Justin Brown David S. Blehert Walter Cottrell John J. Maurer 《Applied and environmental microbiology》2012,78(20):7290-7298
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. 相似文献
14.
Lae-seung Jung Tian Ding Juhee Ahn 《Annals of clinical microbiology and antimicrobials》2017,16(1):66
Background
The emergence of antibiotic-resistant bacteria can cause serious clinical and public health problems. This study describes the possibility of using bacteriophages as an alternative agent to control multidrug-resistant Salmonella Typhimurium.Methods
The potential lytic bacteriophages (P22-B1, P22, PBST10, PBST13, PBST32, and PBST 35) were characterized by morphological property, heat and pH stability, optimum multiplicity of infection (MOI), and lytic activity against S. Typhimurium KCCM 40253, S. Typhimurium ATCC 19585, ciprofloxacin-induced antibiotic-resistant S. Typhimurium ATCC 19585, and S. Typhimurium CCARM 8009.Results
P22-B1 and P22 belong to Podoviridae family and PBST10, PBST13, PBST32, and PBST 35 show a typical structure with polyhedral head and long tail, belonging to Siphoviridae family. Salmonella bacteriophages were highly stable at the temperatures (< 60 °C) and pHs (5.0–11.0). The reduction rates of host cells were increased at the MOI-dependent manner, showing the highest reduction rate at MOI of 10. The host cells were most effectively reduced by P22, while P22-B1 showed the least lytic activity. The ciprofloxacin-induced antibiotic-resistant S. Typhimurium ATCC 19585, and clinically isolated antibiotic-resistant S. Typhimurium CCARM 8009 were resistant to ciprofloxacin, levofloxacin, norfloxacin, and tetracycline. P22 showed the highest lytic activity against S. Typhimurium KCCM 40253 (> 5 log reduction), followed by S. Typhimurium ATCC 19585 (4 log reduction) and ciprofloxacin-induced antibiotic-resistant S. Typhimurium ATCC 19585 (4 log reduction).Conclusion
The results would provide vital insights into the application of lytic bacteriophages as an alternative therapeutics for the control of multidrug-resistant pathogens.15.
Peter J. Hart Colette M. O’Shaughnessy Matthew K. Siggins Saeeda Bobat Robert A. Kingsley David A. Goulding John A. Crump Hugh Reyburn Francesca Micoli Gordon Dougan Adam F. Cunningham Calman A. MacLennan 《PloS one》2016,11(1)
Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies. 相似文献
16.
The genome sequence of Salmonella enterica serovar Choleraesuis, a highly invasive and resistant zoonotic pathogen 总被引:3,自引:0,他引:3
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Chiu CH Tang P Chu C Hu S Bao Q Yu J Chou YY Wang HS Lee YS 《Nucleic acids research》2005,33(5):1690-1698
Salmonella enterica serovar Choleraesuis (S.Choleraesuis), a highly invasive serovar among non-typhoidal Salmonella, usually causes sepsis or extra-intestinal focal infections in humans. S.Choleraesuis infections have now become particularly difficult to treat because of the emergence of resistance to multiple antimicrobial agents. The 4.7 Mb genome sequence of a multidrug-resistant S.Choleraesuis strain SC-B67 was determined. Genome wide comparison of three sequenced Salmonella genomes revealed that more deletion events occurred in S.Choleraesuis SC-B67 and S.Typhi CT18 relative to S.Typhimurium LT2. S.Choleraesuis has 151 pseudogenes, which, among the three Salmonella genomes, include the highest percentage of pseudogenes arising from the genes involved in bacterial chemotaxis signal-transduction pathways. Mutations in these genes may increase smooth swimming of the bacteria, potentially allowing more effective interactions with and invasion of host cells to occur. A key regulatory gene of TetR/AcrR family, acrR, was inactivated through the introduction of an internal stop codon resulting in overexpression of AcrAB that appears to be associated with ciprofloxacin resistance. While lateral gene transfer providing basic functions to allow niche expansion in the host and environment is maintained during the evolution of different serovars of Salmonella, genes providing little overall selective benefit may be lost rapidly. Our findings suggest that the formation of pseudogenes may provide a simple evolutionary pathway that complements gene acquisition to enhance virulence and antimicrobial resistance in S.Choleraesuis. 相似文献
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18.
K Osman I Ibrahim A Yousef T Nabil A Nayerah 《World journal of microbiology & biotechnology》2012,28(5):1997-2001
Bacterial heat-shock response is a global regulatory system required for effective adaptation to changes (stress) in the environment.
An in vitro study was conducted to investigate the impact of a sublethal temperature (42°C) on heat shock protein (HSP) expression
in 6 Salmonella strains (Salmonella Enteritidis, S. Typhimurium, S. Virchow, S. Shubra, S. Haifa and S. Eingedi). The 6 Salmonella strains were isolated from the tissues of ducklings that had died from avian salmonellosis. To
determine the induction of HSP in the 6 Salmonella strains, they were exposed to the selected temperature level for 24 h and further kept for 48 h at culturing condition of
42°C. Growth under a sublethal temperature of 42°C increased the expression of several proteins of Salmonella, including a 63 kDa protein in addition to the generation and/or overexpression of 143 proteins which were specific to heat
shock, concurrent to this acquired thermotolerance. The 6 Salmonella strains responded to 24 h of thermal stress at an elevated temperature 42°C by synthesizing different heat shock proteins
(HSP) with molecular weights ranging between 13.62 and 96.61 kDa. At 48 h, the 6 Salmonella strains synthesized different HSPs with molecular weights ranging between 14.53 and 103.43 kDa. It follows that salmonellae
would produce HSPs during the course of the infectious process. Salmonellosis produced several proteins after 24 and 48 h
of infection. Seven of these proteins (100, 80, 60, 40, 30, 20 and 10 kDa) were recognized in the serum obtained from the
ducklings infected with S. Enteritidis, S. Typhimurium, S. Virchow, S. Shubra, S. Haifa and S. Eingedi after 24 h of infection. After 48 h, the 1–7 kDa HSP became more evident and indicated their de novo generation. 相似文献
19.
Jeyasekaran G. Raj K. Thirumalai Shakila R. Jeya Thangarani A. Jemila Sukumar D. Jailani V. Abdul Kadhar 《World journal of microbiology & biotechnology》2011,27(4):953-959
A multiplex PCR based assay was developed for the identification of the genus Salmonella. Five sets of primers from different genomic sequences such as fimA, himA,
hns, invA and hto genes were selected for the identification of serogroups of Salmonella
enterica such as S. Typhi, S. ParatyphiA, S. Typhimurium, S. Enteritidis and S. Weltevreden. The selected primers amplified products with the sizes of 85, 123, 152, 275 and 496 bp, respectively, for the
genus Salmonella. This assay was found to be highly sensitive, as it could detect 5 cells of Salmonella and 1,000 fg of genomic DNA. Amplification of DNA extracted from other genera viz. V. cholerae and E. coli yielded negative results. This assay provides specific and reliable results and allows for the cost–effective detection of
Salmonella in one reaction tube in mixed bacterial communities. 相似文献
20.
Sheila Bandyopadhyay Xiao Zhang Andrea Ascura Karen L. Edelblum Edward M. Bonder Nan Gao 《Journal of cellular physiology》2024,239(1):e31142
Human enterocytes are primary targets of infection by invasive bacterium Salmonella Typhimurium, and studies using nonintestinal epithelial cells established that S. Typhimurium activates Rho family GTPases, primarily CDC42, to modulate the actin cytoskeletal network for invasion. The host intracellular protein network that engages CDC42 and influences the pathogen's invasive capacity are relatively unclear. Here, proteomic analyses of canonical and variant CDC42 interactomes identified a poorly characterized CDC42 interacting protein, CDC42EP1, whose intracellular localization is rapidly redistributed and aggregated around the invading bacteria. CDC42EP1 associates with SEPTIN-7 and Villin, and its relocalization and bacterial engagement depend on host CDC42 and S. Typhimurium's capability of activating CDC42. Unlike CDC42, CDC42EP1 is not required for S. Typhimurium's initial cellular entry but is found to associate with Salmonella-containing vacuoles after long-term infections, indicating a contribution to the pathogen's intracellular growth and replication. These results uncover a new host regulator of enteric Salmonella infections, which may be targeted to restrict bacterial load at the primary site of infection to prevent systemic spread. 相似文献