Studies on ESBL-producing and multi-drug resistance of <em>Salmonella</em> serovars distributed in Benue State were investigated. A total of four hundred and twenty (420) clinical stool samples, seventy (7...Studies on ESBL-producing and multi-drug resistance of <em>Salmonella</em> serovars distributed in Benue State were investigated. A total of four hundred and twenty (420) clinical stool samples, seventy (70) from each local government area were randomly collected from selected hospitals and analyzed for the presence of <em>Salmonella</em> spp. The isolates were characterized using Gram staining and biochemical tests. The result of AP120E biochemical test strip which contained dehydrated bacterial media and biochemical reagents in twenty (20) separate compartments. The result was obtained by evaluation of the compartments due to observed changes in after 24 hours where others were read by adding up reagents (Ferric chloride, Kovacs V.P reagents). The results were analyzed afterwards in accordance with the manufacturer’s software and positive results with ≥89% potential were confirmed as <em>Salmonella</em> spp. Amplified plasmids derived from 18 <em>Salmonella</em> strains recognized were made up of 23,130 base pairs. ESBL (Extended-spectrum beta-lactamases) genes were located on the plasmids. Two of the ESBL genes found were TEM genes and CTX-M (415 bp). Strains such as <em>S. enterica</em> Typhimurium-CP014981.1, <em>S. enterica</em> Enteritidis-CP007325.2, <em>S. enterica</em> Typhimurium-CP024619.1, <em>S. enterica</em> Typhimurium-CP023166.1, <em>S. bongori-FR877557</em> and <em>S. enterica</em> Enteritidis-TY1 possessed TEM genes where as <em>S. enterica</em> Heidelberg-CP019176.1, <em>S. enterica</em> Typhi-AL513382.1 and <em>S. enterica</em> Typhimurium-MH196335.1 possessed CTX-M. Antibiotic resistance testing was performed using Kirby-Bauer disc diffusion method. The overall percentage susceptibility of the eight antibiotics tested on <em>Salmonella</em> serovars isolates shows that GEN had the highest % susceptibility of 100% followed by NIT (72.2%) and COT (66.7%) before and after plasmid curing. % susceptibility was lower before curing than after curing in CXC, CHL and TET. It was low (5.6%) in ERY while AUG recorded 0% susceptibility. Differences observed in curing status were insignificant (T = 0.33, P > 0.05). The presence of ESBL-producing and multi-drug resistant <em>Salmonella</em> serovars indicates an infection which presents a foremost peril to public health since such infections may be intricate to take care of and may consequently result in death of the infected patients. Constant periodic examination and prevention of drug abuse of antibiotics will assist in ensuring that this trend is curtailed especially in developing nations like Nigeria.展开更多
Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Ente...Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Enteritidis infections in poultry is crucial to protect human health and the poultry industry.In this study,we investigated the effect of co-housing Arbor Acres(AA)chickens,a commercial breed susceptible to S.Enteritidis,with Tibetan chickens,a local breed resistant to S.Enteritidis infection,on the resistance of the latter to the pathogen.Results Ninety-six 1-day-old Tibetan chickens and 961-day-old AA chickens were divided into a Tibetan chicken housed alone group(n=48),an AA chicken housed alone group(n=48),and a co-housed group(48 birds from each breed for 2 cages).All birds were provided the same diet,and the experimental period lasted 14 d.At d 7,all chickens were infected with S.Enteritidis,and samples were collected at 1-,3-,and 7-day-post-infection.We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1-and 3-day-post-infection(P<0.05).In addition,the cecal S.Enteritidis load in AA chickens was significantly reduced at 1-,3-,and 7-day-post-infection(P<0.05).Furthermore,the inflammatory response in AA chickens decreased,as evidenced by the decreased expression of proinflammatory cytokines NOS2,TNF-α,IL-8,IL-1β,and IFN-γin their cecal tonsils(P<0.05).Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells(P<0.05),as well as the expression of claudin-1(P<0.05),a tight junction protein,in the jejunum of AA chickens.Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens;specifically,the relative abundances of harmful microbes,such as Intestinimonas,Oscillibacter,Tuzzerella,Anaerotruncus,Paludicola,and Anaerofilum were reduced(P<0.05).Conclusions Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S.Enteritidis infection without compromising the resistance of Tibetan chickens.This study provides a novel approach for Salmonella control in practical poultry production.展开更多
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
Recent worldwide foodborne outbreaks emphasize the need for the development of rapid and accurate method for pathogen detection. To address such issues, a new colony based label-free detection method working on the pr...Recent worldwide foodborne outbreaks emphasize the need for the development of rapid and accurate method for pathogen detection. To address such issues, a new colony based label-free detection method working on the principles of elastic light scattering was introduced. In order to build libraries of scattering images for bacterial pathogens, it is pertinent to determine the effect of preparation and storage of the agar media on the scatter patterns. Scatter patterns of three Escherichia coli serovars (O26, O111 and O157) were studied and used in a model system, after growth on Sorbitol-MacConkey agar plates that were prepared and stored at different conditions in the laboratory. Quantitative image processing software was used to analyze variation in scatter patterns of the same serovar on media prepared under various standard laboratory conditions and to generate a cross-validation matrix for comparison. Based on the results, it was determined that attention should be given during preparation of media so that the agar plates are not air-dried more than 10 - 20 min after solidification at room temperature. The plates could be stored in sealed bags in cold room (4oC - 10oC) for up to a month before use. The findings of this study should provide guidelines in preparation, storage, and handling of media for generation of reproducible scatter patterns of bacterial colonies with the light scattering sensor for pathogen detection.展开更多
Aim of Study: Leptospirosis is a bacterial zoonotic disease transmitted through contact with animals that are harbouring leptospira. Knowledge of prevalent leptospira in a particular animal of a particular geographica...Aim of Study: Leptospirosis is a bacterial zoonotic disease transmitted through contact with animals that are harbouring leptospira. Knowledge of prevalent leptospira in a particular animal of a particular geographical area is essential to understand the epizootiology of disease, to understand the linkage between circulating serovars in animals and in humans, and to apply appropriate control measures, etc. Material and Methods: Animal samples from different districts of the south Gujarat region received in the Microbiology department during the year of 2020 for the Microscopic agglutination test (MAT) of leptospirosis were included in the study. Results of MAT which was already performed using 12 different serovars were analysed to prevent serovars in a particular animal. Quantitative data were analysed using frequency and percentage. Result: Out of 1406 animal samples, 151 (11 percent) were positive from animals like cows, buffalos, bullocks and goats. More prevalent serovars in cows were L. ictrohemorrahiae (22%), L. hardjo (19%), L. patoc (17%) and L. pyrogen (16%). In buffalo, L. patoc (58%) and L. hardjo (27%) were found. L. hardjo (50%) in bullock and L. automonalis (50%), L. australis (22%) and L. patoc (14%) in goat were found as prevent serovars. Conclusion: Different prevent serovars has been observed in different animals from the different district south Gujarat region which will be helpful to trace the source of infection in human, to apply control measures, to know the epizootiology of disease, for developing strategies in the future during vaccine development with emphasizing more on the prevalent serovars.展开更多
Persistent activation of Survivin and its overexpression contribute to the formation, progression and metastasis of several different tumor types. Therefore, Survivin is an ideal target for RNA interference mediated-g...Persistent activation of Survivin and its overexpression contribute to the formation, progression and metastasis of several different tumor types. Therefore, Survivin is an ideal target for RNA interference mediated-growth inhibition. Blockade of Survivin using specific short hairpin RNAs （shRNA） can significantly reduce prostate tumor growth. RNA interference does not fully ablate target gene expression, owing to the idiosyncrasies associated with shRNAs and their targets. To enhance the therapeutic efficacy of Survivin-specific shRNA, we employed a combinatorial expression of Survivin-specific shRNA and gene associated with retinoid-interferon-induced mortality-19 （GRIM-19）. Then, the GRIM-19 coding sequences and Survivin-specific shRNAs were used to create a dual expression plasmid vector and were carried by an attenuated strain of Salmonella enteric serovar typhimurium （S. typhimurium） to treat prostate cancer in vitro and in vivo. We found that the co-expressed Survivin-specific shRNA and GRIM-19 synergistically and more effectively inhibited prostate tumor proliferation and survival, when compared with treatment with either single agent alone in vitroand in vivo. This study has provided a novel cancer gene therapeutic approach for prostate cancer.展开更多
Objective:To detect leptospiral antibodies by microscopic agglutination test(MAT) in northeast of Iran.Methods:This study was conducted to evaluate prevalence of human leptospiral infections by MAT.using six current r...Objective:To detect leptospiral antibodies by microscopic agglutination test(MAT) in northeast of Iran.Methods:This study was conducted to evaluate prevalence of human leptospiral infections by MAT.using six current reference strains of Leptospira interrogans in north-east of Iran.A total of 285 serum samples were collected from three north-east provinces of Iran,from December,2009 to June,2010.Results:Antibodies were detected at least against one serovar of Leptospira interrogans in 45 sera(15.79%) among 283 samples at a dilution 1:100 or greater.Positive titers against more than one serovar were detected in 24 sera of the positive samples.Therefore, there were 75 positive reactions against different serovar of Leptospira interrogans.Positive titers were recorded against serovar icterohaemorrhagiae(31 samples),hardjo(26 samples), grippotyphosa(7 samples),pomona(5 samples),canicola(4 samples) and ballum(2.sample). Conclusions:In present study the most prevalent(Leptospira icterohaemorrhagiae) and the least prevalent(Leptospira ballum) serovar are different from previous studies.Maybe,species and prevalence of serovars change during the lime in one area and between regions.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
Background： Salmonella enterica serovar Enteritidis （SE）, as a major cause of foodborn illness, infects humans mainly through the egg. However, the symptom of laying hens usually is not typical and hard to diagnosi...Background： Salmonella enterica serovar Enteritidis （SE）, as a major cause of foodborn illness, infects humans mainly through the egg. However, the symptom of laying hens usually is not typical and hard to diagnosis. In the present study, it is studied that the influences of SE infection on layers＇ performance, egg quality and blood biochemical indicators. It will help us to improve the strategy to control SE infection in commercial layers. One hundred layers at 20 wk of age were divided into 2 groups, 60 hens for experiment and others for control. The experiment group was fed with the dosage of 108 CFU SE per hen. The specific PCR was used to detect the deposition of SE. On the 8 d after SE infection, 10 hens from the control group and 30 hens from the experimenta group were slaughtered to detect the SE colonization. The production performance, egg quality and blood biochemical indices were also analyzed. Results： The results showed that the colonization rate of SE was highest in caecum contents （55.17%） and lowest in vagina （17.24%）. For the eggs the detection rate of SE was highest on the eggshell （80.00%） and lowest in yolk （18.81%）. SE infection had no significant influence on production performance and egg qualities （P 〉 0.05）. The difference of laying rate between the experimental and control groups was less than 0.30%, and both were approximately equal to 82.00%. The blood analysis showed that the aspartic aminotransferase （AST） and alanine aminotransferase （ALT） of experimental group was significantly higher than those of control group （P 〈 0.05）. For experimental and control groups AST values were 236.22 U/I and 211.84 U/I respectively, and ALT values were 32.19 U/I and 24.55 U/I. All of coefficients were less than 20%. The colonization of SE in organs increases the enzyme activities of AST and ALT in blood. Conclusions： SE in feed could invade the oviduct and infect the forming eggs. It significantly increased the concentration of ALT and AST in blood. However,SE infection was hard to be observed from the appearances of layer and egg. It might be a dangerous risk to human health.展开更多
Objective.To construct recombinant BCG again st leptospirosis.Methods.We amplified the entire open readin g frame of the OmpL1gene from the genome of the leptospire serovar Lai strain 017.Two recombin ant plasmids pBQ...Objective.To construct recombinant BCG again st leptospirosis.Methods.We amplified the entire open readin g frame of the OmpL1gene from the genome of the leptospire serovar Lai strain 017.Two recombin ant plasmids pBQ1and pBQ2were constructed by oriented ligation based on the E.coli-BCG shuttle plasmids pMV261and pMV361respectively.The recombinant plasmids were transformed into BCG by electroporation.The rBCGs bearing pBQ1and pBQ2were induced by high temperature of 45℃.Results.The expressed product,a 35kD prote in was detected by SDS-PAGE.The resu lt indicates that pBQ1and pBQ2can express OmpL1in rBCG.Conclusion.The technical methods in this study may help detect the immunogenicity a nd immunoprotection of OmpL1and develop more safe,highl y effective rBCG bearing leptospira l antigen with long-lasting protection.展开更多
Objective:To systematically review the etiological agent causing human leptospirosis in Sri Lanka.Methods:Published ailicles on leptospirosis and Leptospira in Sri Lanka were all reviewed to determine serovar,strain a...Objective:To systematically review the etiological agent causing human leptospirosis in Sri Lanka.Methods:Published ailicles on leptospirosis and Leptospira in Sri Lanka were all reviewed to determine serovar,strain and species level indentification of Leptospira.After screening process.74 full text articles/reports were reviewed and among of them.12 published papers describing isolation of Leptospira from Sri Lankan patients/animals.5 molecular epidemiology papers on newer typing methods citing Sri Lanka isolates,with a descriptions of the isolates and 6 published papers reporting PCR based species level identification were identified.Results:Published literature showed that more than 40 strains classified under at least 20 serovars and 10 serogroups have been isolated from Sri Lanka.These isolates belong to four species,namely.Leptospira interrogans,Leptospira kirscluneri.Leptospira borgpetersenii,and Leptospira sanlarosai.In addition.recent studies on direct patient samples without culture and isolation showed Leptospira from Leptospira weilli is also circulating in Sri Lanka.Mulli locus sequence typing showed L3 genotypes of Leptospira from Sri Lankan isolates.Conclusions:This review shows the diversity of Leptospira in Sri Lanka,but culture isolation data has not been published in Sri Lanka during last 30 years.展开更多
US Centers for Disease Control and Prevention (CDC) estimates food-borne pathogenic <em>Salmonella</em> bacteria cause about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the U.S. eve...US Centers for Disease Control and Prevention (CDC) estimates food-borne pathogenic <em>Salmonella</em> bacteria cause about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the U.S. every year. Outbreaks of multidrug-resistant <em>Salmonella</em> Reading linked mainly to raw turkey products and alfalfa sprouts have accounted for human illness including mortality. Therefore, we downloaded and compared genome sequences of 897 <em>Salmonella</em> Reading isolated from 27 resources in 11 countries at 21 year-points from the National Center for Biotechnology Information database. Isolates were clustered into 10 clades which consisted of 3 major and 7 minor or single node clades. Although 3 major clades included both Europe and American isolates, one clade consisted of 605 North American isolates out of 614 isolates. Evolutionary distance is more related to the continent than the source of isolation. The host source, continent (North America and Europe) and phylogenetic clade were related to the prevalence of isolates encoding Antimicrobial Resistance Genes (ARGs). Prevalence of prophages was greater in bovine and swine isolates than poultry and human isolates and the least prevalence was found in human isolates. Between continents, the prevalence of phage was greater in North Ame- rican isolates than European. The diversity of virulence factors in swine isolates differed from poultry isolate while no difference was found among continents. In conclusion, evolutionary distance is related to isolation host source rather than the continent, and genome features were distinguished by host and cluster. Our genomic analysis implies that <em>Salmonella</em> Reading evolved independently to environments within its lineages.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 enterica serovar typhimurium is the first cause identified of food poisoning in humans; new data indicate that the resistant strains of Salmonella sp. can be inhibited by a bacterial population present in f...Salmonella enterica serovar typhimurium is the first cause identified of food poisoning in humans; new data indicate that the resistant strains of Salmonella sp. can be inhibited by a bacterial population present in foods have been called probiotics. Our study was conducted on Swiss albino mice in order to know the effect of probiotics or biotherapeutic agents, and suggest the different therapeutic possibilities of intestinal complications related to the presence of Salmonella enterica serovar typhimurium; Reference strains, Lactobacillus delbrueckii subsp, bulgaricus, Lactobacillus acidophilus and Lactobacillus paracasei in combination with Bifidobacterium sp. were tested for their health benefits. The number of Salmonella enterica serovar typhimurium decreases in intestine, in the stomach and in the liver for group 2, 3 in case of preventive treatment and group 4, 5 in case of a therapeutic treatment due to the use of a cuRure of probiotics, in comparison with group 1 where we recorded a high number. The bio-therapeutic treatment was finally confirmed by macroscopic and microscopic observations of different target organs before and after treatment for the experiment period.展开更多
<i>Bacillus thuringiensis</i> (Bt) parasporal crystal proteins were well known to be toxic to certain insects and cytocidal activity against various human cancer cells. Bt serovar <i>coreanensis</...<i>Bacillus thuringiensis</i> (Bt) parasporal crystal proteins were well known to be toxic to certain insects and cytocidal activity against various human cancer cells. Bt serovar <i>coreanensis</i> ST7, non-pathogenic to insects and non-hemolytic, has an important parasporin, PS4Aa1 (Cry45Aa1), with potential toxicity to human cancer cells. In this study, we reported the feature of complete genome sequence and the cluster of orthologous groups of proteins function classification of ST7. Meanwhile, the evolutionary of ST7 was also studied. The genome data of ST7 will strongly contribute to a better understanding of the genomic diversity and evolution, and enrich the Bt genome database.展开更多
On May 1,2025,Gonzalez-Perez and colleagues(1)reported a multi-country outbreak caused by Salmonella enterica subspecies enterica serovar Mbandaka(S.Mbandaka)that resulted in over 200 cases across Europe.Finland repor...On May 1,2025,Gonzalez-Perez and colleagues(1)reported a multi-country outbreak caused by Salmonella enterica subspecies enterica serovar Mbandaka(S.Mbandaka)that resulted in over 200 cases across Europe.Finland reported the highest number of cases with 97 infections.Whole genome sequencing(WGS)and comparative genomic analyses revealed that the outbreak strains were genetically linked to previously identified strains in the United Kingdom and to pre-cooked,frozen chicken meat used in ready-to-eat products.Subsequently,on May 5,2025,the United States of America(USA)Centers for Disease Control and Prevention(CDC)announced a Salmonella outbreak associated with backyard poultry(2).As of May 19,2025,this outbreak had expanded to 104 confirmed infections,with at least 33 individuals contracting Salmonella following contact with backyard poultry.Tragically,one death has been reported in Illinois.Scientific evidence demonstrates that S.Mbandaka isolated from patient samples,and matched the strain found in shipping boxes used to transport poultry from hatcheries to agricultural retail stores.展开更多
Objectives:To assess the variations in hypertonic tolerance among Salmonella enterica serovar Newport(S.Newport)strains isolated from diverse sources and investigate the mechanism underlying the tolerance differences ...Objectives:To assess the variations in hypertonic tolerance among Salmonella enterica serovar Newport(S.Newport)strains isolated from diverse sources and investigate the mechanism underlying the tolerance differences between the sensitive and tolerant strain.Materials and Methods:In this work,various S.Newport strains were cultured in 5%and 10%NaCl solutions(hypertonic stress),and the most sensitive and tolerant strains were selected using a Weibull model.The regulatory mechanisms underlying the hypertonic tolerance differences of S.Newport were preliminarily investigated in the aspects of cell phenotype,intracellular solute concentration,and gene expression level.Results:With prolonged hypertonic stress time,the leakage of nucleic acids and proteins of S.Newport increased gradually,and the membrane potential of S.Newport declined after increasing.Compared with the sensitive strain,the tolerant counterpart exhibited the ability to maintain the integrity of the cell membrane and sustain a high membrane potential level.The expression levels of the upstream genes proV and otsB in the tolerant strain were signifcantly lower than those in the sensitive strain;but the Kdp and Trk systems and downstream genes proX,proW,and otsA were highly expressed in the tolerant strain compared with the sensitive strain,leading to higher concentrations of intracellular K+and trehalose,enabling better survival in a hypertonic environment.Conclusions:The fndings of this work offer valuable insights into pathogen survival mechanisms under hypertonic stress and contribute to the development of strategies for mitigating microbiological risks during long-term processing and storage in the cured food industry.展开更多
文摘Studies on ESBL-producing and multi-drug resistance of <em>Salmonella</em> serovars distributed in Benue State were investigated. A total of four hundred and twenty (420) clinical stool samples, seventy (70) from each local government area were randomly collected from selected hospitals and analyzed for the presence of <em>Salmonella</em> spp. The isolates were characterized using Gram staining and biochemical tests. The result of AP120E biochemical test strip which contained dehydrated bacterial media and biochemical reagents in twenty (20) separate compartments. The result was obtained by evaluation of the compartments due to observed changes in after 24 hours where others were read by adding up reagents (Ferric chloride, Kovacs V.P reagents). The results were analyzed afterwards in accordance with the manufacturer’s software and positive results with ≥89% potential were confirmed as <em>Salmonella</em> spp. Amplified plasmids derived from 18 <em>Salmonella</em> strains recognized were made up of 23,130 base pairs. ESBL (Extended-spectrum beta-lactamases) genes were located on the plasmids. Two of the ESBL genes found were TEM genes and CTX-M (415 bp). Strains such as <em>S. enterica</em> Typhimurium-CP014981.1, <em>S. enterica</em> Enteritidis-CP007325.2, <em>S. enterica</em> Typhimurium-CP024619.1, <em>S. enterica</em> Typhimurium-CP023166.1, <em>S. bongori-FR877557</em> and <em>S. enterica</em> Enteritidis-TY1 possessed TEM genes where as <em>S. enterica</em> Heidelberg-CP019176.1, <em>S. enterica</em> Typhi-AL513382.1 and <em>S. enterica</em> Typhimurium-MH196335.1 possessed CTX-M. Antibiotic resistance testing was performed using Kirby-Bauer disc diffusion method. The overall percentage susceptibility of the eight antibiotics tested on <em>Salmonella</em> serovars isolates shows that GEN had the highest % susceptibility of 100% followed by NIT (72.2%) and COT (66.7%) before and after plasmid curing. % susceptibility was lower before curing than after curing in CXC, CHL and TET. It was low (5.6%) in ERY while AUG recorded 0% susceptibility. Differences observed in curing status were insignificant (T = 0.33, P > 0.05). The presence of ESBL-producing and multi-drug resistant <em>Salmonella</em> serovars indicates an infection which presents a foremost peril to public health since such infections may be intricate to take care of and may consequently result in death of the infected patients. Constant periodic examination and prevention of drug abuse of antibiotics will assist in ensuring that this trend is curtailed especially in developing nations like Nigeria.
基金supported by the Earmarked fund for China Agriculture Research System of MOF and MARA(Grant No.CARS-41-G01).
文摘Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Enteritidis infections in poultry is crucial to protect human health and the poultry industry.In this study,we investigated the effect of co-housing Arbor Acres(AA)chickens,a commercial breed susceptible to S.Enteritidis,with Tibetan chickens,a local breed resistant to S.Enteritidis infection,on the resistance of the latter to the pathogen.Results Ninety-six 1-day-old Tibetan chickens and 961-day-old AA chickens were divided into a Tibetan chicken housed alone group(n=48),an AA chicken housed alone group(n=48),and a co-housed group(48 birds from each breed for 2 cages).All birds were provided the same diet,and the experimental period lasted 14 d.At d 7,all chickens were infected with S.Enteritidis,and samples were collected at 1-,3-,and 7-day-post-infection.We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1-and 3-day-post-infection(P<0.05).In addition,the cecal S.Enteritidis load in AA chickens was significantly reduced at 1-,3-,and 7-day-post-infection(P<0.05).Furthermore,the inflammatory response in AA chickens decreased,as evidenced by the decreased expression of proinflammatory cytokines NOS2,TNF-α,IL-8,IL-1β,and IFN-γin their cecal tonsils(P<0.05).Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells(P<0.05),as well as the expression of claudin-1(P<0.05),a tight junction protein,in the jejunum of AA chickens.Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens;specifically,the relative abundances of harmful microbes,such as Intestinimonas,Oscillibacter,Tuzzerella,Anaerotruncus,Paludicola,and Anaerofilum were reduced(P<0.05).Conclusions Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S.Enteritidis infection without compromising the resistance of Tibetan chickens.This study provides a novel approach for Salmonella control in practical poultry production.
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Recent worldwide foodborne outbreaks emphasize the need for the development of rapid and accurate method for pathogen detection. To address such issues, a new colony based label-free detection method working on the principles of elastic light scattering was introduced. In order to build libraries of scattering images for bacterial pathogens, it is pertinent to determine the effect of preparation and storage of the agar media on the scatter patterns. Scatter patterns of three Escherichia coli serovars (O26, O111 and O157) were studied and used in a model system, after growth on Sorbitol-MacConkey agar plates that were prepared and stored at different conditions in the laboratory. Quantitative image processing software was used to analyze variation in scatter patterns of the same serovar on media prepared under various standard laboratory conditions and to generate a cross-validation matrix for comparison. Based on the results, it was determined that attention should be given during preparation of media so that the agar plates are not air-dried more than 10 - 20 min after solidification at room temperature. The plates could be stored in sealed bags in cold room (4oC - 10oC) for up to a month before use. The findings of this study should provide guidelines in preparation, storage, and handling of media for generation of reproducible scatter patterns of bacterial colonies with the light scattering sensor for pathogen detection.
文摘Aim of Study: Leptospirosis is a bacterial zoonotic disease transmitted through contact with animals that are harbouring leptospira. Knowledge of prevalent leptospira in a particular animal of a particular geographical area is essential to understand the epizootiology of disease, to understand the linkage between circulating serovars in animals and in humans, and to apply appropriate control measures, etc. Material and Methods: Animal samples from different districts of the south Gujarat region received in the Microbiology department during the year of 2020 for the Microscopic agglutination test (MAT) of leptospirosis were included in the study. Results of MAT which was already performed using 12 different serovars were analysed to prevent serovars in a particular animal. Quantitative data were analysed using frequency and percentage. Result: Out of 1406 animal samples, 151 (11 percent) were positive from animals like cows, buffalos, bullocks and goats. More prevalent serovars in cows were L. ictrohemorrahiae (22%), L. hardjo (19%), L. patoc (17%) and L. pyrogen (16%). In buffalo, L. patoc (58%) and L. hardjo (27%) were found. L. hardjo (50%) in bullock and L. automonalis (50%), L. australis (22%) and L. patoc (14%) in goat were found as prevent serovars. Conclusion: Different prevent serovars has been observed in different animals from the different district south Gujarat region which will be helpful to trace the source of infection in human, to apply control measures, to know the epizootiology of disease, for developing strategies in the future during vaccine development with emphasizing more on the prevalent serovars.
基金This study was supported by the National Natural Science Foundation of China （No. 30801354 and No. 3097079J）, Jilin Provincial Science and Technology Department （No. 20080154 and No.20110146） and the PhD Programs Foundation of Ministry of Education of China （No. 200801831077） （Ling Zhang）
文摘Persistent activation of Survivin and its overexpression contribute to the formation, progression and metastasis of several different tumor types. Therefore, Survivin is an ideal target for RNA interference mediated-growth inhibition. Blockade of Survivin using specific short hairpin RNAs （shRNA） can significantly reduce prostate tumor growth. RNA interference does not fully ablate target gene expression, owing to the idiosyncrasies associated with shRNAs and their targets. To enhance the therapeutic efficacy of Survivin-specific shRNA, we employed a combinatorial expression of Survivin-specific shRNA and gene associated with retinoid-interferon-induced mortality-19 （GRIM-19）. Then, the GRIM-19 coding sequences and Survivin-specific shRNAs were used to create a dual expression plasmid vector and were carried by an attenuated strain of Salmonella enteric serovar typhimurium （S. typhimurium） to treat prostate cancer in vitro and in vivo. We found that the co-expressed Survivin-specific shRNA and GRIM-19 synergistically and more effectively inhibited prostate tumor proliferation and survival, when compared with treatment with either single agent alone in vitroand in vivo. This study has provided a novel cancer gene therapeutic approach for prostate cancer.
基金Supported by a grant form Research Council of Shahid BahonarUniversity of Kerman.Iran
文摘Objective:To detect leptospiral antibodies by microscopic agglutination test(MAT) in northeast of Iran.Methods:This study was conducted to evaluate prevalence of human leptospiral infections by MAT.using six current reference strains of Leptospira interrogans in north-east of Iran.A total of 285 serum samples were collected from three north-east provinces of Iran,from December,2009 to June,2010.Results:Antibodies were detected at least against one serovar of Leptospira interrogans in 45 sera(15.79%) among 283 samples at a dilution 1:100 or greater.Positive titers against more than one serovar were detected in 24 sera of the positive samples.Therefore, there were 75 positive reactions against different serovar of Leptospira interrogans.Positive titers were recorded against serovar icterohaemorrhagiae(31 samples),hardjo(26 samples), grippotyphosa(7 samples),pomona(5 samples),canicola(4 samples) and ballum(2.sample). Conclusions:In present study the most prevalent(Leptospira icterohaemorrhagiae) and the least prevalent(Leptospira ballum) serovar are different from previous studies.Maybe,species and prevalence of serovars change during the lime in one area and between regions.
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supported by National System for Layer Production Technology of China(CARS-41)Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China "Study on Poultry Eggs and Meat Detection Technology"(IRT0945)Chinese Universities Scientific Fund(2013QJ069)
文摘Background： Salmonella enterica serovar Enteritidis （SE）, as a major cause of foodborn illness, infects humans mainly through the egg. However, the symptom of laying hens usually is not typical and hard to diagnosis. In the present study, it is studied that the influences of SE infection on layers＇ performance, egg quality and blood biochemical indicators. It will help us to improve the strategy to control SE infection in commercial layers. One hundred layers at 20 wk of age were divided into 2 groups, 60 hens for experiment and others for control. The experiment group was fed with the dosage of 108 CFU SE per hen. The specific PCR was used to detect the deposition of SE. On the 8 d after SE infection, 10 hens from the control group and 30 hens from the experimenta group were slaughtered to detect the SE colonization. The production performance, egg quality and blood biochemical indices were also analyzed. Results： The results showed that the colonization rate of SE was highest in caecum contents （55.17%） and lowest in vagina （17.24%）. For the eggs the detection rate of SE was highest on the eggshell （80.00%） and lowest in yolk （18.81%）. SE infection had no significant influence on production performance and egg qualities （P 〉 0.05）. The difference of laying rate between the experimental and control groups was less than 0.30%, and both were approximately equal to 82.00%. The blood analysis showed that the aspartic aminotransferase （AST） and alanine aminotransferase （ALT） of experimental group was significantly higher than those of control group （P 〈 0.05）. For experimental and control groups AST values were 236.22 U/I and 211.84 U/I respectively, and ALT values were 32.19 U/I and 24.55 U/I. All of coefficients were less than 20%. The colonization of SE in organs increases the enzyme activities of AST and ALT in blood. Conclusions： SE in feed could invade the oviduct and infect the forming eggs. It significantly increased the concentration of ALT and AST in blood. However,SE infection was hard to be observed from the appearances of layer and egg. It might be a dangerous risk to human health.
文摘Objective.To construct recombinant BCG again st leptospirosis.Methods.We amplified the entire open readin g frame of the OmpL1gene from the genome of the leptospire serovar Lai strain 017.Two recombin ant plasmids pBQ1and pBQ2were constructed by oriented ligation based on the E.coli-BCG shuttle plasmids pMV261and pMV361respectively.The recombinant plasmids were transformed into BCG by electroporation.The rBCGs bearing pBQ1and pBQ2were induced by high temperature of 45℃.Results.The expressed product,a 35kD prote in was detected by SDS-PAGE.The resu lt indicates that pBQ1and pBQ2can express OmpL1in rBCG.Conclusion.The technical methods in this study may help detect the immunogenicity a nd immunoprotection of OmpL1and develop more safe,highl y effective rBCG bearing leptospira l antigen with long-lasting protection.
文摘Objective:To systematically review the etiological agent causing human leptospirosis in Sri Lanka.Methods:Published ailicles on leptospirosis and Leptospira in Sri Lanka were all reviewed to determine serovar,strain and species level indentification of Leptospira.After screening process.74 full text articles/reports were reviewed and among of them.12 published papers describing isolation of Leptospira from Sri Lankan patients/animals.5 molecular epidemiology papers on newer typing methods citing Sri Lanka isolates,with a descriptions of the isolates and 6 published papers reporting PCR based species level identification were identified.Results:Published literature showed that more than 40 strains classified under at least 20 serovars and 10 serogroups have been isolated from Sri Lanka.These isolates belong to four species,namely.Leptospira interrogans,Leptospira kirscluneri.Leptospira borgpetersenii,and Leptospira sanlarosai.In addition.recent studies on direct patient samples without culture and isolation showed Leptospira from Leptospira weilli is also circulating in Sri Lanka.Mulli locus sequence typing showed L3 genotypes of Leptospira from Sri Lankan isolates.Conclusions:This review shows the diversity of Leptospira in Sri Lanka,but culture isolation data has not been published in Sri Lanka during last 30 years.
文摘US Centers for Disease Control and Prevention (CDC) estimates food-borne pathogenic <em>Salmonella</em> bacteria cause about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the U.S. every year. Outbreaks of multidrug-resistant <em>Salmonella</em> Reading linked mainly to raw turkey products and alfalfa sprouts have accounted for human illness including mortality. Therefore, we downloaded and compared genome sequences of 897 <em>Salmonella</em> Reading isolated from 27 resources in 11 countries at 21 year-points from the National Center for Biotechnology Information database. Isolates were clustered into 10 clades which consisted of 3 major and 7 minor or single node clades. Although 3 major clades included both Europe and American isolates, one clade consisted of 605 North American isolates out of 614 isolates. Evolutionary distance is more related to the continent than the source of isolation. The host source, continent (North America and Europe) and phylogenetic clade were related to the prevalence of isolates encoding Antimicrobial Resistance Genes (ARGs). Prevalence of prophages was greater in bovine and swine isolates than poultry and human isolates and the least prevalence was found in human isolates. Between continents, the prevalence of phage was greater in North Ame- rican isolates than European. The diversity of virulence factors in swine isolates differed from poultry isolate while no difference was found among continents. In conclusion, evolutionary distance is related to isolation host source rather than the continent, and genome features were distinguished by host and cluster. Our genomic analysis implies that <em>Salmonella</em> Reading evolved independently to environments within its lineages.
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 enterica serovar typhimurium is the first cause identified of food poisoning in humans; new data indicate that the resistant strains of Salmonella sp. can be inhibited by a bacterial population present in foods have been called probiotics. Our study was conducted on Swiss albino mice in order to know the effect of probiotics or biotherapeutic agents, and suggest the different therapeutic possibilities of intestinal complications related to the presence of Salmonella enterica serovar typhimurium; Reference strains, Lactobacillus delbrueckii subsp, bulgaricus, Lactobacillus acidophilus and Lactobacillus paracasei in combination with Bifidobacterium sp. were tested for their health benefits. The number of Salmonella enterica serovar typhimurium decreases in intestine, in the stomach and in the liver for group 2, 3 in case of preventive treatment and group 4, 5 in case of a therapeutic treatment due to the use of a cuRure of probiotics, in comparison with group 1 where we recorded a high number. The bio-therapeutic treatment was finally confirmed by macroscopic and microscopic observations of different target organs before and after treatment for the experiment period.
文摘<i>Bacillus thuringiensis</i> (Bt) parasporal crystal proteins were well known to be toxic to certain insects and cytocidal activity against various human cancer cells. Bt serovar <i>coreanensis</i> ST7, non-pathogenic to insects and non-hemolytic, has an important parasporin, PS4Aa1 (Cry45Aa1), with potential toxicity to human cancer cells. In this study, we reported the feature of complete genome sequence and the cluster of orthologous groups of proteins function classification of ST7. Meanwhile, the evolutionary of ST7 was also studied. The genome data of ST7 will strongly contribute to a better understanding of the genomic diversity and evolution, and enrich the Bt genome database.
基金Supported in part by grants from the Project for the Young Scientist of the Joint Funds of Science and Technology Research and Development Plan of Henan Province,China(235200810058)the National Key Research and Development Program of China(2023YFC2307101)the Young Top-Notch Talents Foundation of Henan Agricultural University(30501278).
文摘On May 1,2025,Gonzalez-Perez and colleagues(1)reported a multi-country outbreak caused by Salmonella enterica subspecies enterica serovar Mbandaka(S.Mbandaka)that resulted in over 200 cases across Europe.Finland reported the highest number of cases with 97 infections.Whole genome sequencing(WGS)and comparative genomic analyses revealed that the outbreak strains were genetically linked to previously identified strains in the United Kingdom and to pre-cooked,frozen chicken meat used in ready-to-eat products.Subsequently,on May 5,2025,the United States of America(USA)Centers for Disease Control and Prevention(CDC)announced a Salmonella outbreak associated with backyard poultry(2).As of May 19,2025,this outbreak had expanded to 104 confirmed infections,with at least 33 individuals contracting Salmonella following contact with backyard poultry.Tragically,one death has been reported in Illinois.Scientific evidence demonstrates that S.Mbandaka isolated from patient samples,and matched the strain found in shipping boxes used to transport poultry from hatcheries to agricultural retail stores.
基金supported by the National Natural Science Foundation of China(Nos.32302271 and 32272431).
文摘Objectives:To assess the variations in hypertonic tolerance among Salmonella enterica serovar Newport(S.Newport)strains isolated from diverse sources and investigate the mechanism underlying the tolerance differences between the sensitive and tolerant strain.Materials and Methods:In this work,various S.Newport strains were cultured in 5%and 10%NaCl solutions(hypertonic stress),and the most sensitive and tolerant strains were selected using a Weibull model.The regulatory mechanisms underlying the hypertonic tolerance differences of S.Newport were preliminarily investigated in the aspects of cell phenotype,intracellular solute concentration,and gene expression level.Results:With prolonged hypertonic stress time,the leakage of nucleic acids and proteins of S.Newport increased gradually,and the membrane potential of S.Newport declined after increasing.Compared with the sensitive strain,the tolerant counterpart exhibited the ability to maintain the integrity of the cell membrane and sustain a high membrane potential level.The expression levels of the upstream genes proV and otsB in the tolerant strain were signifcantly lower than those in the sensitive strain;but the Kdp and Trk systems and downstream genes proX,proW,and otsA were highly expressed in the tolerant strain compared with the sensitive strain,leading to higher concentrations of intracellular K+and trehalose,enabling better survival in a hypertonic environment.Conclusions:The fndings of this work offer valuable insights into pathogen survival mechanisms under hypertonic stress and contribute to the development of strategies for mitigating microbiological risks during long-term processing and storage in the cured food industry.
