BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE S...BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.展开更多
Objective:To develop allenualed slrains of Salmonella enterica serorar Typhi(S.typhi) for the candidate vaccine by osmolar stress.Mothods:S.typhi SS3 and SS5 strains were isolated from asymptomatic typhoid carriers in...Objective:To develop allenualed slrains of Salmonella enterica serorar Typhi(S.typhi) for the candidate vaccine by osmolar stress.Mothods:S.typhi SS3 and SS5 strains were isolated from asymptomatic typhoid carriers in Mamakkal,Tamil Nadu.India.Both strains were grown in LB(Luria Bertani) medium supplemented with various concentration of NaCl(0.1- 0.7M) respectively.The effecl of osmolar stress was determined at molecular level by PCR using MCR 06 and MCR07 primers corresponding to ompR with chromosomal DNA of S.typhi SS3 and SS5 strains.Attenuation by osmolar stress results in deletion mutation of the.S.typhi slrains was determined by agglutination assays,precipitation method.SDS PAGE analysis and by animal models.Results:The 799 bp amplified ompR gene product from wild type S.typhi SS3 and SS5 illustrate the presence of virulent gene.Interestingly,there was only a 282 bp amplified product from S.typhi SS3 and SS5 grown in the presence of 0.5.0.6 and 0.7 M NaCl.This illustrates the occurrence of deletion mutation in ompR gene al high concentration of NaCl.Furthermore,both the wildtype and mutant S.typhi outer membrane SDS-PAGF.profile reveals the differences in the expression of ompF.ompC and ompA proteins.In mice,wild type and mutant strains lethal dose(LD_(50)) were determined.The mice died within 72 h when both the wild type strains were injected intraperitoneally with 3 log CFU-mL^(-1).When the mice were injected with the mutants in same dosage,no clinical symptoms were observed;whereas the serum antibodv litre was elicited within two weeks indicated that the mutants have the ability to induce protective humoral immune response.These results suggest that S.typhi SS3 and SS5 may bo used as good candidate strains for the development of live attenuated vaccine against salmonellosis.Conclusions:This study demonstrates that the S.typhi strains were allenualed and could be good vaccine candidates in future.展开更多
Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica...Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica, salamae, arizonae,展开更多
本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分...本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分泌物;动态污染研究表明:沙门氏菌能在姜块中迅速繁殖,显著提高姜块超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)的活性。该研究表明,沙门氏菌能以生姜为寄主存活。展开更多
Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene a...Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene and kanamycin gene were PCR amplified.Each of these DNA fragment was cloned into p GEM T-easy vector.The construct was confirmed by PCR and restriction digest.Results:PCR amplified 320,206 and 835 bp DNA fragments were subcloned into p ET-32 vector resulting with a plasmid called p ET-32-sip C up-kan-sip C down.Conclusions:The new plasmid(p ET-32-sip C up-kan-sip C down)is useful for genetic engineering and for future manipulation of S.typhimurium sip C gene.展开更多
Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Meth...Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Methods:The antibacterial activity of ethanolic extract of tulsi, 0.sanctum,leaf(TLE:500μg) for 23 S.typhi isolates was determined following agar diffusion. The C(30μg) and Tm(5μg) activity alone and in combination with TLE(250μg) was determined by disk diffusion.The zone diameter of inhibition(ZDI) for the agents was recorded, and growth inhibitory indices(Glls) were calculated.Results:The S.typhi isolates(n=23),which were resistant to both C(ZDI 6 mm) and Tm(ZDI 6 mm),had TLE(500μg) ZDIs 16-24 mm.The ZDIs of C and Tm were increased up to 15-21 mm and 17-23 mm,respectively,when TLE(250μg) was added to the C and Tm discs.The Glls ranged 0.789-1.235 and 0.894-1.352,due to combined activity against S.typhi isolates,of C and TLE and Tm and TLE.respeclivelv.Conclusions:The data suggest that TLE,in combination with C and Tm,had synergistic activity for S.typhi isolates, and hence O.sanclum is potential in combating S.typhi drug resistance,as well promising in the development of non-antibiotic drug for S.typhi infection.展开更多
Objective: To identify the region conferring stability to pBSSB2(a linear plasmid, pBSSB1, containing a kanamycin cassette), which is unique to Indonesian isolates of Salmonella enterica serovar Typhi. Methods: The op...Objective: To identify the region conferring stability to pBSSB2(a linear plasmid, pBSSB1, containing a kanamycin cassette), which is unique to Indonesian isolates of Salmonella enterica serovar Typhi. Methods: The open reading frame(ORF) 009 was identified as a toxin coding gene in the plasmid through introduction of translational termination codons in the ORF. Results: The stability function was located in a fragment that spanned nucleotides 5 766 to 6 828 in the linear plasmid genetic map. Ectopic expression of ORF009 in pBAD18 vector indicated ORF009 codes for a toxin. This fragment could stabilize plasmid pUC18 previously destabilized through mutation of the pcnB(plasmid copy number control) gene that codes for polyA polymerase. Majority of the cells expressing ORF009 were non-viable according to phase contrast microscopy. Conclusions: This study demonstrated that a linear plasmid fragment that carries a gene encoding a toxin possibly conferred stability to the parent plasmid. It was able to stabilize a multicopy plasmid of Escherichia coli.展开更多
Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major publi...Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major public health issue worldwide in the 1980s. The main causative food material of SE food poisoning is chicken eggs, and many outbreaks of food poisoning caused by chicken eggs occurred throughout the world. SE epidemics occurred in layer farms, and this was the main cause of SE-induced food poisoning in humans. The major subject of our epidemiological study described in this report is why SE-contaminated eggs became the main causative food. In this study, we focused on difference of molecular expression for farm-isolated SEs. That is because recent studies have demonstrated that O-antigen enlargement may be related to pathogenicity in mice as well as 22-kDa polypeptide-expression (SEp22). We have discovered that many SE strains isolated from chicken farms do not express SEp22, and a deficiency or decreased level of cellular antigen 0-12 in SE strains isolated from chicken farms was clarified in a report. Additionally, SEp22 was deficient in SE strains passaged through chickens, whereas SEp22 was expressed at a high level in SE strains passaged through mice. These findings suggest that SE infection and retention more effectively occur in layer farms than in other animal maintenance environments, which may be a basis of the epidemiological hypothesis to explain the high-levelproduction of SE-contaminated eggs (the presence of mice may be the basis of the retention of SE infection in layer farms, and this may also be the mechanism causing the high-level production of SE-contaminated eggs).展开更多
Salmonella is a common cause of foodborne illness within the United States with the severity of the infection being a factor of both the age and overall health of the infected individual. The nematode worm Caenorhabdi...Salmonella is a common cause of foodborne illness within the United States with the severity of the infection being a factor of both the age and overall health of the infected individual. The nematode worm Caenorhabditis elegans has proven to be a useful model to study infection dynamics of pathogenic bacteria, including Salmonella enterica, and its short lifespan makes it a powerful model system to assess the effect of organismal age on infection severity. In this study, we infected C. elegans with each of 6 serovars of S. enterica at 1, 3 or 5 days of worm age and monitored their survival. Worms infected with E. coli OP50 were used as a control. Infection with S. enterica resulted in a significant reduction in mean longevity relative to OP50 (p < 0.05);however, there was no significant effect of age on mean survival time regardless of the strain of bacteria used.展开更多
Food-borne salmonellosis continues to be a major health concern worldwide. Carry-contamination of Salmonella frequently occurs in meat production. We focused on cell dynamics of swine fibroblasts after infection with ...Food-borne salmonellosis continues to be a major health concern worldwide. Carry-contamination of Salmonella frequently occurs in meat production. We focused on cell dynamics of swine fibroblasts after infection with Salmonella enterica serovar Enteritidis and Typhimurium, because fibroblast can be a target cell for Salmonella latent infection. It was found that both S. Enteritidis and S. Typhimurium were able to adhere and invade to swine fibroblasts. The proliferations in fibroblasts were different between each serovar. S. Enteritidis reached to the maximum at 24 hr after infection while S. Typhimurium did not. In addition, the decrease in the G<sub>0</sub>/G<sub>1</sub> phase cells and increase in G<sub>2</sub>/M phase cells on the fibroblast were observed by both Salmonella infection. Cell death including apoptosis in the cells was inhibited by the infection of Salmonella. These results suggest that nontyphoidal Salmonella can survive for the long term by modifying bacterial cell proliferation and preventing cell death of host cells.展开更多
<span><i><span style="font-family:""><i></span></i></span><span><span><i><span style="font-family:"">Salmonella enterica&...<span><i><span style="font-family:""><i></span></i></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> serovars is a leading cause of human gastroenteritis, and the incidence of salmonellosis is constantly increasing, causing millions of infections and many deaths annually. The detection of the pathogen in optimal terms is an essential factor for reducing the impact on the human body. In this work</span></span></span><span><span><span style="font-family:"">,</span></span></span><span><span><span style="font-family:""> SYBR Green I-based qPCR method of detection and quantifica<span>tion of </span></span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><i><span style="font-family:""> </span></i></span></span><span><span><span style="font-family:"">was</span></span></span><span><span><span style="font-family:""> developed and validated. For detection o</span></span></span><span><span><span style="font-family:"">f </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> subsp.<i> </i></span></span></span><span><span><i><span style="font-family:""><i></span></i></span></span><span><span><i><span style="font-family:"">enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:"">, two pairs of primers were designed using publically available Primer-BLAST software. Primer efficiency was calculated <span>by establishing a standard curve. The specificity, sensitivity, accuracy, and</span> precision of PCR results were tested. Both primer pairs showed an acceptable performance, proving the developed techniques were sensitive, reliable and precise. The validated <span>qPCR technology has a good potential to replace the traditional culture method in microbial diagnosis.展开更多
Alginate oligosaccharides(AOS),extracted from marine brown algae,are a common functional feed additive;however,it remains unclear whether they modulate the gut microbiota and microbial metabolites.The response of Salm...Alginate oligosaccharides(AOS),extracted from marine brown algae,are a common functional feed additive;however,it remains unclear whether they modulate the gut microbiota and microbial metabolites.The response of Salmonella enterica serovar Typhimurium,a common poultry pathogen,to AOS fermented with chicken fecal inocula was investigated using metabolomic and transcriptomic analyses.Single-strain cultivation tests showed that AOS did not directly inhibit the growth of S.Typhimurium.However,when AOS were fermented by chicken fecal microbiota,the supernatant of fermented AOS(F-AOS)exhibited remarkable antibacterial activity against S.Typhimurium,decreasing the abundance ratio of S.Typhimurium in the fecal microbiota from 18.94 to 2.94%.Transcriptomic analyses showed that the 855 diferentially expressed genes induced by F-AOS were mainly enriched in porphyrin and chlorophyll metabolism,oxidative phosphorylation,and Salmonella infection-related pathways.RT-qPCR confrmed that F-AOS downregulated key genes involved in fagellar assembly and the type III secretory system of S.Typhimurium,indicating metabolites in F-AOS can infuence the growth and metabolism of S.Typhimurium.Metabolomic analyses showed that 205 microbial metabolites were signifcantly altered in F-AOS.Among them,the increase in indolelactic acid and 3-indolepropionic acid levels were further confrmed using HPLC.This study provides a new perspective for the application of AOS as a feed additive against pathogenic intestinal bacteria.展开更多
During infectious disease episodes, pathogens express distinct subsets of virulence factors which allow them to adapt to different environments. Hence, genes that are expressed or upregulated in vivo are implicated in...During infectious disease episodes, pathogens express distinct subsets of virulence factors which allow them to adapt to different environments. Hence, genes that are expressed or upregulated in vivo are implicated in pathogenesis. We used in vivo induced antigen technology (IVIAT) to identify antigens which are expressed during infection with Salmonella enterica serovar Typhi. We identified 7 in vivo induced (IVI) antigens, which included BcfD (a fimbrial structural subunit), GrxC (a glutaredoxin 3), SapB (an ABC-type transport system), T3663 (an ABC-type uncharacterized transport system), T3816 (a putative rhodanese-related sulfurtransferase), T1497 (a probable TonB-dependent receptor) and T3689 (unknown function). Of the 7 identified antigens, 5 antigens had no cross-immunoreactivity in adsorbed control sera from healthy subjects. These 5 included BcfD, GrxC, SapB, T3663 and T3689. Antigens identified in this study are potential targets for drug and vaccine development and may be utilized as diagnostic agents.展开更多
pRST98 is a chimeric plasmid isolated from Salmonella enterica serovar Typhi(S.typhi)that mediates the functions of drug resistance and virulence.Previously,we reported that Salmonella plasmid virulence(spv)genes were...pRST98 is a chimeric plasmid isolated from Salmonella enterica serovar Typhi(S.typhi)that mediates the functions of drug resistance and virulence.Previously,we reported that Salmonella plasmid virulence(spv)genes were present in S.typhi.In our current study,we investigated whether plasmid pRST98 exhibits significant cytotoxicity in macrophages.pRST98 was transferred into the avirulent Salmonella enterica serovar Typhimurium(S.typhimurium)strain RIA to create the transconjugant pRST98/RIA.The standard S.typhimurium virulent strain SR-11,which carries a 100-kb virulence plasmid,was used as a positive control.The bacterial strains were incubated with a murine macrophage-like cell line(J774A.1)in vitro.Apoptosis of J774A.1 cells was examined by electron microscopy and flow cytometry after annexin-V/propidium iodide labeling,and the survival of Salmonella strains in J774A.1 cells was determined.Results showed that macrophages infected with strain pRST98/RIA displayed greater levels of apoptosis than those infected with RIA and that pRST98 may increase bacterial survival in macrophages.Further studies showed that the pRST98-induced death of macrophages was associated with the loss of mitochondrial membrane potential and that pRST98 may activate caspase-9 and then caspase-3.The research data indicate that the virulence of bacteria that contain the pRST98 plasmid is enhanced;the presence of this plasmid increases the survival of the bacterial pathogen and acts through the mitochondrial pathway to mediate macrophage apoptosis.展开更多
Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recogni...Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recognize S. enterica and raise defense responses. Nonetheless, the molecular mechanisms controlling the interaction of S. enterica with plants are still largely unclear. Here, we show that flagellin from S. enterica represents a prominent pathogenassociated molecular pattern （PAMP） in Arabidopsis thaliana, which induces PAMP-triggered immunity （PTI） via the recognition of the fig22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system （T3SS） mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the fig22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI.展开更多
The emergence and spread of plasmid-mediated tigecycline resistance genes have attracted extensive attention worldwide.We investigated the distribution of mobile tigecycline resistance genes in Salmonella genomes gene...The emergence and spread of plasmid-mediated tigecycline resistance genes have attracted extensive attention worldwide.We investigated the distribution of mobile tigecycline resistance genes in Salmonella genomes generated by both our laboratory and public bacterial genomes downloaded from the NCBI GenBank.The tet(X4)-positive strains were subjected to susceptibility testing and conjugation assays.The genetic features of the tet(X4)-bearing plasmid sequence were analyzed.Here,we report the identification of the plasmid-mediated tigecycline resistance gene tet(X4)in a conjugative plasmid of the Salmonella enterica serovar Llandoff strain SH16G3606,isolated from a man in China in 2016,the first reported serovar Llandoff in China as a novel sequence type ST8300.The tet(X4)-mediated resistance phenotype was successfully transferred from the Salmonella Llandoff strain into Escherichia coli J53,resulting in a 32-fold increase in the minimal inhibitory concentration of tigecycline.The tet(X4)gene was located between two copies of ISCR2 in the plasmid pSal21GXH-tetX4.To our knowledge,this is the first report of the plasmid-mediated tigecycline resistance gene tet(X4)in a Salmonella Llandoff strain isolated from a human stool sample in China.In addition,our findings demonstrated that a total of 171 isolates are carrying tet(X)-like genes distributed in 21 countries or areas across 6 continents,posing a serious threat to humans and public health.Overall,our timely discovery of the recent emergence of the tet(X4)gene in Salmonella isolates and other Enterobacteriaceae bacteria species supports the need for rapid surveillance to prevent the tet(X)-like gene from spreading.展开更多
Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived fo...Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived foods such as raw poultry and pork.This study aimed to characterize the genetic diversity,plasmid replicon types,and antibiotic resistance of 15 S.1,4,[5],12:i:-environmental isolates collected from two poultry farms using pulsed-field gel electrophoresis(PFGE),multilocus sequence typing(MLST),polymerase chain reaction-based replicon typing,and minimum inhibitory concentration approach.Ten different PFGE genotypes were detected,indicating a high diversity among these S.1,4,[5],12:i:-isolates.Three sequence types(ST19,ST1544,ST34)were identified by MLST.Among them,ST1544 was first detected in S.1,4,[5],12:i:-environmental isolates from poultry farms.All isolates were resistant to cefazolin,cefotetan,tobramycin,amikacin,and gentamicin,but susceptible to piperacillin-tazobactam,aztreonam,ceftazidime,cefepime,and ertapenem.Five incompatibility groups(Inc)of plasmids were identified,including IncFIIs(66.7%),IncHI2(20%),IncI1(6.7%),IncN(6.7%),and IncQ(6.7%).Among these isolates,80%carried at least one plasmid replicon type,and 20%carried multiple plasmid replicon types.Interestingly,the multidrug-resistant isolate 263 carried numerous resistance genes(i.e.qnrS,aac(6ʹ)-Ib-cr,bla_(TEM),bla_(CTX-M-9),bla_(OXA-1),sul1,sul2,sul3,floR,and mcr-1)and class I integronase gene intI1,which possessed both IncHI2 and IncQ plasmids,suggesting that resistance genes may be horizontally transferred by the combination of IncHI2 and IncQ plasmids.Collectively,antibiotic-resistant S.1,4,[5],12:i:-isolates were first found in poultry farm environments in China,and surveillance should be strengthened to prevent their further spread from poultry farms to foods.展开更多
基金Supported by Zhejiang Province Health and Wellness Science and Technology Program in 2022,China,No.2022RC202.
文摘BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.
文摘Objective:To develop allenualed slrains of Salmonella enterica serorar Typhi(S.typhi) for the candidate vaccine by osmolar stress.Mothods:S.typhi SS3 and SS5 strains were isolated from asymptomatic typhoid carriers in Mamakkal,Tamil Nadu.India.Both strains were grown in LB(Luria Bertani) medium supplemented with various concentration of NaCl(0.1- 0.7M) respectively.The effecl of osmolar stress was determined at molecular level by PCR using MCR 06 and MCR07 primers corresponding to ompR with chromosomal DNA of S.typhi SS3 and SS5 strains.Attenuation by osmolar stress results in deletion mutation of the.S.typhi slrains was determined by agglutination assays,precipitation method.SDS PAGE analysis and by animal models.Results:The 799 bp amplified ompR gene product from wild type S.typhi SS3 and SS5 illustrate the presence of virulent gene.Interestingly,there was only a 282 bp amplified product from S.typhi SS3 and SS5 grown in the presence of 0.5.0.6 and 0.7 M NaCl.This illustrates the occurrence of deletion mutation in ompR gene al high concentration of NaCl.Furthermore,both the wildtype and mutant S.typhi outer membrane SDS-PAGF.profile reveals the differences in the expression of ompF.ompC and ompA proteins.In mice,wild type and mutant strains lethal dose(LD_(50)) were determined.The mice died within 72 h when both the wild type strains were injected intraperitoneally with 3 log CFU-mL^(-1).When the mice were injected with the mutants in same dosage,no clinical symptoms were observed;whereas the serum antibodv litre was elicited within two weeks indicated that the mutants have the ability to induce protective humoral immune response.These results suggest that S.typhi SS3 and SS5 may bo used as good candidate strains for the development of live attenuated vaccine against salmonellosis.Conclusions:This study demonstrates that the S.typhi strains were allenualed and could be good vaccine candidates in future.
基金financially supported by the University of Malaya Research Grant (UMRG) (RP003A-13BIO)UM Postgraduate Research Fund (PPP) (PS319/2010B)
文摘Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica, salamae, arizonae,
文摘本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分泌物;动态污染研究表明:沙门氏菌能在姜块中迅速繁殖,显著提高姜块超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)的活性。该研究表明,沙门氏菌能以生姜为寄主存活。
文摘Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene and kanamycin gene were PCR amplified.Each of these DNA fragment was cloned into p GEM T-easy vector.The construct was confirmed by PCR and restriction digest.Results:PCR amplified 320,206 and 835 bp DNA fragments were subcloned into p ET-32 vector resulting with a plasmid called p ET-32-sip C up-kan-sip C down.Conclusions:The new plasmid(p ET-32-sip C up-kan-sip C down)is useful for genetic engineering and for future manipulation of S.typhimurium sip C gene.
文摘Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Methods:The antibacterial activity of ethanolic extract of tulsi, 0.sanctum,leaf(TLE:500μg) for 23 S.typhi isolates was determined following agar diffusion. The C(30μg) and Tm(5μg) activity alone and in combination with TLE(250μg) was determined by disk diffusion.The zone diameter of inhibition(ZDI) for the agents was recorded, and growth inhibitory indices(Glls) were calculated.Results:The S.typhi isolates(n=23),which were resistant to both C(ZDI 6 mm) and Tm(ZDI 6 mm),had TLE(500μg) ZDIs 16-24 mm.The ZDIs of C and Tm were increased up to 15-21 mm and 17-23 mm,respectively,when TLE(250μg) was added to the C and Tm discs.The Glls ranged 0.789-1.235 and 0.894-1.352,due to combined activity against S.typhi isolates,of C and TLE and Tm and TLE.respeclivelv.Conclusions:The data suggest that TLE,in combination with C and Tm,had synergistic activity for S.typhi isolates, and hence O.sanclum is potential in combating S.typhi drug resistance,as well promising in the development of non-antibiotic drug for S.typhi infection.
文摘Objective: To identify the region conferring stability to pBSSB2(a linear plasmid, pBSSB1, containing a kanamycin cassette), which is unique to Indonesian isolates of Salmonella enterica serovar Typhi. Methods: The open reading frame(ORF) 009 was identified as a toxin coding gene in the plasmid through introduction of translational termination codons in the ORF. Results: The stability function was located in a fragment that spanned nucleotides 5 766 to 6 828 in the linear plasmid genetic map. Ectopic expression of ORF009 in pBAD18 vector indicated ORF009 codes for a toxin. This fragment could stabilize plasmid pUC18 previously destabilized through mutation of the pcnB(plasmid copy number control) gene that codes for polyA polymerase. Majority of the cells expressing ORF009 were non-viable according to phase contrast microscopy. Conclusions: This study demonstrated that a linear plasmid fragment that carries a gene encoding a toxin possibly conferred stability to the parent plasmid. It was able to stabilize a multicopy plasmid of Escherichia coli.
文摘Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major public health issue worldwide in the 1980s. The main causative food material of SE food poisoning is chicken eggs, and many outbreaks of food poisoning caused by chicken eggs occurred throughout the world. SE epidemics occurred in layer farms, and this was the main cause of SE-induced food poisoning in humans. The major subject of our epidemiological study described in this report is why SE-contaminated eggs became the main causative food. In this study, we focused on difference of molecular expression for farm-isolated SEs. That is because recent studies have demonstrated that O-antigen enlargement may be related to pathogenicity in mice as well as 22-kDa polypeptide-expression (SEp22). We have discovered that many SE strains isolated from chicken farms do not express SEp22, and a deficiency or decreased level of cellular antigen 0-12 in SE strains isolated from chicken farms was clarified in a report. Additionally, SEp22 was deficient in SE strains passaged through chickens, whereas SEp22 was expressed at a high level in SE strains passaged through mice. These findings suggest that SE infection and retention more effectively occur in layer farms than in other animal maintenance environments, which may be a basis of the epidemiological hypothesis to explain the high-levelproduction of SE-contaminated eggs (the presence of mice may be the basis of the retention of SE infection in layer farms, and this may also be the mechanism causing the high-level production of SE-contaminated eggs).
文摘Salmonella is a common cause of foodborne illness within the United States with the severity of the infection being a factor of both the age and overall health of the infected individual. The nematode worm Caenorhabditis elegans has proven to be a useful model to study infection dynamics of pathogenic bacteria, including Salmonella enterica, and its short lifespan makes it a powerful model system to assess the effect of organismal age on infection severity. In this study, we infected C. elegans with each of 6 serovars of S. enterica at 1, 3 or 5 days of worm age and monitored their survival. Worms infected with E. coli OP50 were used as a control. Infection with S. enterica resulted in a significant reduction in mean longevity relative to OP50 (p < 0.05);however, there was no significant effect of age on mean survival time regardless of the strain of bacteria used.
文摘Food-borne salmonellosis continues to be a major health concern worldwide. Carry-contamination of Salmonella frequently occurs in meat production. We focused on cell dynamics of swine fibroblasts after infection with Salmonella enterica serovar Enteritidis and Typhimurium, because fibroblast can be a target cell for Salmonella latent infection. It was found that both S. Enteritidis and S. Typhimurium were able to adhere and invade to swine fibroblasts. The proliferations in fibroblasts were different between each serovar. S. Enteritidis reached to the maximum at 24 hr after infection while S. Typhimurium did not. In addition, the decrease in the G<sub>0</sub>/G<sub>1</sub> phase cells and increase in G<sub>2</sub>/M phase cells on the fibroblast were observed by both Salmonella infection. Cell death including apoptosis in the cells was inhibited by the infection of Salmonella. These results suggest that nontyphoidal Salmonella can survive for the long term by modifying bacterial cell proliferation and preventing cell death of host cells.
文摘<span><i><span style="font-family:""><i></span></i></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> serovars is a leading cause of human gastroenteritis, and the incidence of salmonellosis is constantly increasing, causing millions of infections and many deaths annually. The detection of the pathogen in optimal terms is an essential factor for reducing the impact on the human body. In this work</span></span></span><span><span><span style="font-family:"">,</span></span></span><span><span><span style="font-family:""> SYBR Green I-based qPCR method of detection and quantifica<span>tion of </span></span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><i><span style="font-family:""> </span></i></span></span><span><span><span style="font-family:"">was</span></span></span><span><span><span style="font-family:""> developed and validated. For detection o</span></span></span><span><span><span style="font-family:"">f </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> subsp.<i> </i></span></span></span><span><span><i><span style="font-family:""><i></span></i></span></span><span><span><i><span style="font-family:"">enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:"">, two pairs of primers were designed using publically available Primer-BLAST software. Primer efficiency was calculated <span>by establishing a standard curve. The specificity, sensitivity, accuracy, and</span> precision of PCR results were tested. Both primer pairs showed an acceptable performance, proving the developed techniques were sensitive, reliable and precise. The validated <span>qPCR technology has a good potential to replace the traditional culture method in microbial diagnosis.
基金This work was supported by the National Key Research and Development Program of China(2019YFD0901800 and 2019YFD0900201)National Natural Science Foundation of China(32202064)China Postdoctoral Science Foundation(2021M701547).
文摘Alginate oligosaccharides(AOS),extracted from marine brown algae,are a common functional feed additive;however,it remains unclear whether they modulate the gut microbiota and microbial metabolites.The response of Salmonella enterica serovar Typhimurium,a common poultry pathogen,to AOS fermented with chicken fecal inocula was investigated using metabolomic and transcriptomic analyses.Single-strain cultivation tests showed that AOS did not directly inhibit the growth of S.Typhimurium.However,when AOS were fermented by chicken fecal microbiota,the supernatant of fermented AOS(F-AOS)exhibited remarkable antibacterial activity against S.Typhimurium,decreasing the abundance ratio of S.Typhimurium in the fecal microbiota from 18.94 to 2.94%.Transcriptomic analyses showed that the 855 diferentially expressed genes induced by F-AOS were mainly enriched in porphyrin and chlorophyll metabolism,oxidative phosphorylation,and Salmonella infection-related pathways.RT-qPCR confrmed that F-AOS downregulated key genes involved in fagellar assembly and the type III secretory system of S.Typhimurium,indicating metabolites in F-AOS can infuence the growth and metabolism of S.Typhimurium.Metabolomic analyses showed that 205 microbial metabolites were signifcantly altered in F-AOS.Among them,the increase in indolelactic acid and 3-indolepropionic acid levels were further confrmed using HPLC.This study provides a new perspective for the application of AOS as a feed additive against pathogenic intestinal bacteria.
基金Supported by the National Natural Science Foundation of China (Grant No. 30500435)
文摘During infectious disease episodes, pathogens express distinct subsets of virulence factors which allow them to adapt to different environments. Hence, genes that are expressed or upregulated in vivo are implicated in pathogenesis. We used in vivo induced antigen technology (IVIAT) to identify antigens which are expressed during infection with Salmonella enterica serovar Typhi. We identified 7 in vivo induced (IVI) antigens, which included BcfD (a fimbrial structural subunit), GrxC (a glutaredoxin 3), SapB (an ABC-type transport system), T3663 (an ABC-type uncharacterized transport system), T3816 (a putative rhodanese-related sulfurtransferase), T1497 (a probable TonB-dependent receptor) and T3689 (unknown function). Of the 7 identified antigens, 5 antigens had no cross-immunoreactivity in adsorbed control sera from healthy subjects. These 5 included BcfD, GrxC, SapB, T3663 and T3689. Antigens identified in this study are potential targets for drug and vaccine development and may be utilized as diagnostic agents.
基金supported by the Natural Science Foundation of China(No.30972768)the Special and General Postdoctoral Science Foundation of China(No.200902529 and No.20080430178)+1 种基金the Natural Science Foundation of Jiangsu High Education Institute of China(No.08KJB310009)the Social Development Science Foundation of Suzhou City of China(No.SS08025).
文摘pRST98 is a chimeric plasmid isolated from Salmonella enterica serovar Typhi(S.typhi)that mediates the functions of drug resistance and virulence.Previously,we reported that Salmonella plasmid virulence(spv)genes were present in S.typhi.In our current study,we investigated whether plasmid pRST98 exhibits significant cytotoxicity in macrophages.pRST98 was transferred into the avirulent Salmonella enterica serovar Typhimurium(S.typhimurium)strain RIA to create the transconjugant pRST98/RIA.The standard S.typhimurium virulent strain SR-11,which carries a 100-kb virulence plasmid,was used as a positive control.The bacterial strains were incubated with a murine macrophage-like cell line(J774A.1)in vitro.Apoptosis of J774A.1 cells was examined by electron microscopy and flow cytometry after annexin-V/propidium iodide labeling,and the survival of Salmonella strains in J774A.1 cells was determined.Results showed that macrophages infected with strain pRST98/RIA displayed greater levels of apoptosis than those infected with RIA and that pRST98 may increase bacterial survival in macrophages.Further studies showed that the pRST98-induced death of macrophages was associated with the loss of mitochondrial membrane potential and that pRST98 may activate caspase-9 and then caspase-3.The research data indicate that the virulence of bacteria that contain the pRST98 plasmid is enhanced;the presence of this plasmid increases the survival of the bacterial pathogen and acts through the mitochondrial pathway to mediate macrophage apoptosis.
文摘Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recognize S. enterica and raise defense responses. Nonetheless, the molecular mechanisms controlling the interaction of S. enterica with plants are still largely unclear. Here, we show that flagellin from S. enterica represents a prominent pathogenassociated molecular pattern （PAMP） in Arabidopsis thaliana, which induces PAMP-triggered immunity （PTI） via the recognition of the fig22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system （T3SS） mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the fig22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI.
基金This study was supported by the Major Program of National Natural Science Foundation of China(81991534)the Major State Basic Research Development Program(2018YFC1603803)the National Key Research and Development Program of China(grant number:2018YFC1603900).
文摘The emergence and spread of plasmid-mediated tigecycline resistance genes have attracted extensive attention worldwide.We investigated the distribution of mobile tigecycline resistance genes in Salmonella genomes generated by both our laboratory and public bacterial genomes downloaded from the NCBI GenBank.The tet(X4)-positive strains were subjected to susceptibility testing and conjugation assays.The genetic features of the tet(X4)-bearing plasmid sequence were analyzed.Here,we report the identification of the plasmid-mediated tigecycline resistance gene tet(X4)in a conjugative plasmid of the Salmonella enterica serovar Llandoff strain SH16G3606,isolated from a man in China in 2016,the first reported serovar Llandoff in China as a novel sequence type ST8300.The tet(X4)-mediated resistance phenotype was successfully transferred from the Salmonella Llandoff strain into Escherichia coli J53,resulting in a 32-fold increase in the minimal inhibitory concentration of tigecycline.The tet(X4)gene was located between two copies of ISCR2 in the plasmid pSal21GXH-tetX4.To our knowledge,this is the first report of the plasmid-mediated tigecycline resistance gene tet(X4)in a Salmonella Llandoff strain isolated from a human stool sample in China.In addition,our findings demonstrated that a total of 171 isolates are carrying tet(X)-like genes distributed in 21 countries or areas across 6 continents,posing a serious threat to humans and public health.Overall,our timely discovery of the recent emergence of the tet(X4)gene in Salmonella isolates and other Enterobacteriaceae bacteria species supports the need for rapid surveillance to prevent the tet(X)-like gene from spreading.
基金supported by the National Natural Science Foundation of China(No.32102111)the Project was funded by the China Postdoctoral Science Foundation(2021M702194).
文摘Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived foods such as raw poultry and pork.This study aimed to characterize the genetic diversity,plasmid replicon types,and antibiotic resistance of 15 S.1,4,[5],12:i:-environmental isolates collected from two poultry farms using pulsed-field gel electrophoresis(PFGE),multilocus sequence typing(MLST),polymerase chain reaction-based replicon typing,and minimum inhibitory concentration approach.Ten different PFGE genotypes were detected,indicating a high diversity among these S.1,4,[5],12:i:-isolates.Three sequence types(ST19,ST1544,ST34)were identified by MLST.Among them,ST1544 was first detected in S.1,4,[5],12:i:-environmental isolates from poultry farms.All isolates were resistant to cefazolin,cefotetan,tobramycin,amikacin,and gentamicin,but susceptible to piperacillin-tazobactam,aztreonam,ceftazidime,cefepime,and ertapenem.Five incompatibility groups(Inc)of plasmids were identified,including IncFIIs(66.7%),IncHI2(20%),IncI1(6.7%),IncN(6.7%),and IncQ(6.7%).Among these isolates,80%carried at least one plasmid replicon type,and 20%carried multiple plasmid replicon types.Interestingly,the multidrug-resistant isolate 263 carried numerous resistance genes(i.e.qnrS,aac(6ʹ)-Ib-cr,bla_(TEM),bla_(CTX-M-9),bla_(OXA-1),sul1,sul2,sul3,floR,and mcr-1)and class I integronase gene intI1,which possessed both IncHI2 and IncQ plasmids,suggesting that resistance genes may be horizontally transferred by the combination of IncHI2 and IncQ plasmids.Collectively,antibiotic-resistant S.1,4,[5],12:i:-isolates were first found in poultry farm environments in China,and surveillance should be strengthened to prevent their further spread from poultry farms to foods.
