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Microbes and Infection Jul 2001Salmonella infection is associated with the increased expression of inducible nitric oxide synthase in macrophages and other cells. This review summarizes current... (Review)
Review
Salmonella infection is associated with the increased expression of inducible nitric oxide synthase in macrophages and other cells. This review summarizes current knowledge of the molecular mechanisms involved in the induction process, and discusses the functional significance of nitric oxide production in the context of host defense against Salmonella.
Topics: Animals; Cell Line; Humans; Macrophages; Mice; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Salmonella; Salmonella Infections; Salmonella Infections, Animal
PubMed: 11489426
DOI: 10.1016/s1286-4579(01)01428-9 -
Cell Host & Microbe Aug 2016Pathogenic bacteria must withstand diverse host environments during infection. Environmental signals, such as pH, temperature, nutrient limitation, etc., not only... (Review)
Review
Pathogenic bacteria must withstand diverse host environments during infection. Environmental signals, such as pH, temperature, nutrient limitation, etc., not only trigger adaptive responses within bacteria to these specific stress conditions but also direct the expression of virulence genes at an appropriate time and place. An appreciation of stress responses and their regulation is therefore essential for an understanding of bacterial pathogenesis. This review considers specific stresses in the host environment and their relevance to pathogenesis, with a particular focus on the enteric pathogen Salmonella.
Topics: Adaptation, Physiological; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Salmonella; Salmonella Infections; Stress, Physiological; Virulence Factors
PubMed: 27512901
DOI: 10.1016/j.chom.2016.07.009 -
Emerging Microbes & Infections Dec 2022Invasive infection, which can cause typhoid/paratyphoid fever and invasive non-typhoidal salmonellosis, is a public health burden in Africa. Accurate diagnosis and...
Invasive infection, which can cause typhoid/paratyphoid fever and invasive non-typhoidal salmonellosis, is a public health burden in Africa. Accurate diagnosis and etiological characterization are required to conduct prevalence and risk estimations for infection; however, the utilization of optimal techniques and surveillance data are still insufficient. In this study, we performed a laboratory-based survey in Freetown, which is the biggest city in Sierra Leone with a high burden of typhoid fever, by using blood culture and molecular methods but not the Widal test, to estimate the prevalence and aetiology of invasive infection among fever patients. We found a very low prevalence of typhoid fever in patients with fever during the investigation period, and this prevalence was clearly overestimated by the Widal test. Genome sequencing of the . Typhi isolate from this work revealed that the strain carried multiple antibiotic resistance genes, and an epidemic clone that has existed in West Africa for years was also detected in Sierra Leone. By using metagenomic sequencing, one patient with invasive non-typhoidal salmonellosis was identified as having bacterial co-infections. Our data highlight that surveillance based on accurate laboratory diagnosis and genome sequencing needs to be strengthened to provide a better estimation of the real epidemics and enable potential risk assessment by etiological analysis in Africa. Even in a laboratory with only basic equipment, it is possible to conduct next-generation sequencing for pathogen discovery in bloodstream infections and to determine the etiological characteristics of pathogene without complex combinations of laboratory methods.
Topics: Fever; High-Throughput Nucleotide Sequencing; Humans; Pathology, Molecular; Salmonella Infections; Salmonella typhi; Sierra Leone; Typhoid Fever
PubMed: 35537043
DOI: 10.1080/22221751.2022.2076612 -
The Journal of Antimicrobial... Dec 2017We determined the interactions between efficacy of antibiotic treatment, pathogen growth rates and between-organ spread during systemic Salmonella infections.
OBJECTIVES
We determined the interactions between efficacy of antibiotic treatment, pathogen growth rates and between-organ spread during systemic Salmonella infections.
METHODS
We infected mice with isogenic molecularly tagged subpopulations of either a fast-growing WT or a slow-growing ΔaroC Salmonella strain. We monitored viable bacterial numbers and fluctuations in the proportions of each bacterial subpopulation in spleen, liver, blood and mesenteric lymph nodes (MLNs) before, during and after the cessation of treatment with ampicillin and ciprofloxacin.
RESULTS
Both antimicrobials induced a reduction in viable bacterial numbers in the spleen, liver and blood. This reduction was biphasic in infections with fast-growing bacteria, with a rapid initial reduction followed by a phase of lower effect. Conversely, a slow and gradual reduction of the bacterial load was seen in infections with the slow-growing strain, indicating a positive correlation between bacterial net growth rates and the efficacy of ampicillin and ciprofloxacin. The viable numbers of either bacterial strain remained constant in MLNs throughout the treatment with a relapse of the infection with WT bacteria occurring after cessation of the treatment. The frequency of each tagged bacterial subpopulation was similar in the spleen and liver, but different from that of the MLNs before, during and after treatment.
CONCLUSIONS
In Salmonella infections, bacterial growth rates correlate with treatment efficacy. MLNs are a site with a bacterial population structure different to those of the spleen and liver and where the total viable bacterial load remains largely unaffected by antimicrobials, but can resume growth after cessation of treatment.
Topics: Ampicillin; Animal Structures; Animals; Anti-Bacterial Agents; Bacterial Load; Blood; Ciprofloxacin; Disease Models, Animal; Female; Mice, Inbred C57BL; Salmonella; Salmonella Infections; Sepsis; Spatio-Temporal Analysis
PubMed: 28962012
DOI: 10.1093/jac/dkx294 -
Frontiers in Immunology 2021DT104 infection causes the death of , which can be prevented by certain isolates. However, the molecular mechanisms of both the host response to the infection and the...
DT104 infection causes the death of , which can be prevented by certain isolates. However, the molecular mechanisms of both the host response to the infection and the protection by are largely unclear. The present study has investigated the life-span and gene expression of both wild-type (WT) and mutants in some key components of cell signaling in response to infection and protection from . The results indicated that the gene expression of in the DAF/ insulin-like growth factor (DAF/IGF) pathway, and in the programmed cell death (PCD) pathway, , and for antimicrobial peptide production, and involved in the production of other defense molecules was all significantly upregulated when the wild-type (WT) was subjected to DT104 infection. On the contrary, the gene expression of , and in the p38 mitogen-activated protein kinase (MAPK) pathway and , and for the production of other defense molecules was significantly suppressed by DT104. Pretreatment of the worms with LB1 significantly upregulated the expression of almost all the tested genes except for , and compared with the nematode infected with DT104 only. Mutants defective in the cell signaling or other defense molecules of were either more susceptible (defective in , or ) or more resistant (defective in or ) to DT104 infection than the WT except for the mutant defective in . Mutants defective in antimicrobial peptides ( or ) were also more susceptible than the WT. In contrast, the mutant defective in became more resistant. When all the mutants were pretreated with LB1, five mutants that are defective in , or showed no response to the protection from LB1. These results suggest that LB1 can regulate cell signaling including the p38 MAPK pathway and downstream production of antimicrobial peptides and defense molecules to combat infection.
Topics: Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Lactobacillus; MAP Kinase Signaling System; Pore Forming Cytotoxic Proteins; Probiotics; Salmonella Infections; Salmonella typhimurium; p38 Mitogen-Activated Protein Kinases
PubMed: 33763087
DOI: 10.3389/fimmu.2021.653205 -
Biosensors May 2022Salmonellosis is a major cause of foodborne infections, caused by , posing a major health risk. It possesses the ability to infiltrate the food supply chain at any point... (Review)
Review
Salmonellosis is a major cause of foodborne infections, caused by , posing a major health risk. It possesses the ability to infiltrate the food supply chain at any point throughout the manufacturing, distribution, processing or quality control process. infection has increased severely and requires effective and efficient methods for early monitoring and detection. Traditional methods, such as real-time polymerase chain reaction and culture plate, consume a lot of time and are labor-intensive. Therefore, new quick detection methods for on-field applications are urgently needed. Biosensors provide consumer-friendly approaches for quick on-field diagnoses. In the last few years, there has been a surge in research into the creation of reliable and advanced electrochemical sensors for the detection of strains in food samples. Electrochemical sensors provide extensive accuracy and reproducible results. Herein, we present a comprehensive overview of electrochemical sensors for the detection of by focusing on various mechanisms of electrochemical transducer. Further, we explain new-generation biosensors (microfluidics, CRISPR- and IOT-based) for point-of care applications. This review also highlights the limitations of developing biosensors in detection and future possibilities.
Topics: Biosensing Techniques; Electrochemical Techniques; Humans; Real-Time Polymerase Chain Reaction; Salmonella; Salmonella Food Poisoning; Salmonella Infections; Time Factors
PubMed: 35735514
DOI: 10.3390/bios12060365 -
Pediatrics and Neonatology Jul 2021This study investigated whether the appropriate antibiotics therapy affects the fecal excretion time in pediatric salmonellosis of different severities and explored the...
BACKGROUND
This study investigated whether the appropriate antibiotics therapy affects the fecal excretion time in pediatric salmonellosis of different severities and explored the factors associated with the fecal excretion time of nontyphoid Salmonella.
METHODS
Between 2012 and 2017, admitted children with nontyphoid salmonellosis who consented to receive consecutive stool cultures every 4-7 days until 2 consecutive negative results were obtained were enrolled. Patients were stratified into no, appropriate (bacteremia or severe patients receiving antibiotics active in vitro), and inappropriate antibiotics (patients with mild or moderate severity receiving antibiotics or severe receiving antibiotics resistant in vitro) therapy groups. A previously proposed severity score was used to classify the patients into severe, moderate, and mild severity classes. The demographics, clinical manifestations, laboratory data and severity were compared among the groups. To explore the factors associated with the fecal excretion time of nontyphoid Salmonella, univariate and multivariate analyses were performed using linear regression analysis.
RESULTS
This study enrolled 126 children with nontyphoid salmonellosis; 58 and 18 in the mild and severe classes, respectively. The no, appropriate and inappropriate antibiotics therapy groups comprised 69, 24 and 33 patients, respectively. The mean fecal excretion time was 12.17 days. The appropriate antibiotics therapy group had comparable fecal excretion time with that of no antibiotics group. Age <1 year, increased white blood cell count, decreased hemoglobin, and inappropriate antibiotics therapy significantly prolonged fecal excretion time in univariate analysis (p < 0.05). The multivariate analysis showed that inappropriate antibiotics therapy and decreased hemoglobin significantly prolonged the fecal excretion time.
CONCLUSION
Inappropriate antibiotics therapy and decreased hemoglobin prolong the fecal excretion time of nontyphoid Salmonella, whereas appropriate antibiotics therapy does not. Continuous monitoring of antibiotic resistance and judicious use of antibiotics in children with nontyphoid salmonellosis are necessary.
Topics: Anti-Bacterial Agents; Bacteremia; Child; Humans; Salmonella; Salmonella Infections
PubMed: 33903054
DOI: 10.1016/j.pedneo.2021.03.016 -
The Canadian Veterinary Journal = La... Sep 1998Salmonella typhimurium phage type (PT) or definitive type (DT) 104 is a virulent pathogen for humans and animals, particularly cattle. It has been isolated increasingly... (Review)
Review
Salmonella typhimurium phage type (PT) or definitive type (DT) 104 is a virulent pathogen for humans and animals, particularly cattle. It has been isolated increasingly from humans and animals in the United Kingdom and several other European countries and, more recently, in the United States and Canada. Humans may acquire the infection from foods of animal origin contaminated with the infective organism. Farm families are particularly at risk of acquiring the infection by contact with infected animals or by drinking unpasteurized milk. The symptoms in cattle are watery to bloody diarrhea, a drop in milk production, pyrexia, anorexia, dehydration and depression. Infection may result in septicemic salmonellosis and, upon necropsy, a fibrinonecrotic enterocolitis may be observed. The infection occurs more commonly in the calving season than at other times. Feedlot cattle and pigs may also be affected. Prolonged carriage and shedding of the pathogen may occur. Symptoms in humans consist of diarrhea, fever, headache, nausea, abdominal pain, vomiting, and, less frequently, blood in the stool. Salmonella typhimurium DT104 strains are commonly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline.
Topics: Agricultural Workers' Diseases; Animals; Canada; Cattle; Cattle Diseases; Diarrhea; Drug Resistance, Microbial; Drug Resistance, Multiple; Europe; Humans; Salmonella Infections; Salmonella Infections, Animal; Salmonella typhimurium; Swine; Swine Diseases; United States; Virulence; Zoonoses
PubMed: 9752592
DOI: No ID Found -
Revue Scientifique Et Technique... Aug 2000Fowl typhoid (FT) and pullorum disease (PD) are septicaemic diseases, primarily of chickens and turkeys, caused by Gram negative bacteria, Salmonella Gallinarum and S.... (Review)
Review
Fowl typhoid (FT) and pullorum disease (PD) are septicaemic diseases, primarily of chickens and turkeys, caused by Gram negative bacteria, Salmonella Gallinarum and S. Pullorum, respectively. Clinical signs in chicks and poults include anorexia, diarrhoea, dehydration, weakness and high mortality. In mature fowl, FT and PD are manifested by decreased egg production, fertility, hatchability and anorexia, and increased mortality. Gross and microscopic lesions due to FT and PD in chicks and poults include hepatitis, splenitis, typhlitis, omphalitis, myocarditis, ventriculitis, pneumonia, synovitis, peritonitis and ophthalmitis. In mature fowl, lesions include oophoritis, salpingitis, orchitis, peritonitis and perihepatitis. Transovarian infection resulting in infection of the egg and subsequently the chick or poult is one of the most important modes of transmission of these two diseases. Salmonella Gallinarum and S. Pullorum can be isolated by use of selective and non-selective media. Salmonella Pullorum produces rapid decarboxylation of ornithine whereas S. Gallinarum does not, an important biochemical difference between the two bacteria. Both FT and PD can be detected serologically by use of a macroscopic tube agglutination test, rapid serum test, stained antigen whole blood test or microagglutination test. Both diseases can be controlled and eradicated by use of serological testing and elimination of positive birds. Vaccines may be used to control the disease and antibiotics for the treatment of FT and PD. Although FT and PD are widely distributed throughout the world, the diseases have been eradicated from commercial poultry in developed countries such as the United States of America, Canada and most countries of Western Europe. Both S. Gallinarum and S. Pullorum are highly adapted to the host species, and therefore are of little public health significance.
Topics: Animals; Chickens; Poultry Diseases; Salmonella Infections, Animal; Turkeys
PubMed: 10935271
DOI: 10.20506/rst.19.2.1222 -
Epidemiology and Infection Jun 2017Salmonella spp. comprise the second most common food-borne pathogens in the European Union (EU). The role of pigs as carriers of Salmonella has been intensively studied... (Review)
Review
Salmonella spp. comprise the second most common food-borne pathogens in the European Union (EU). The role of pigs as carriers of Salmonella has been intensively studied both on farm and at slaughter. Salmonella infection in pigs may cause fever, diarrhoea, prostration and mortality. However, most infected pigs remain healthy carriers, and those infected at the end of the fattening period could pose a threat to human health. Contamination of pig carcasses can occur on the slaughter line, and it is linked to cross-contamination from other carcasses and the presence of Salmonella in the environment. Therefore, Salmonella serovars present on pig carcasses can be different from those detected in the same bathes on the farm. In recent years, S. Typhimurium, S. Derby and S. serotype 4,[5],12:i:- (a monophasic variant of S. Typhimurium) have been the most common serovars to be detected in pigs in EU countries, but S. Rissen, S. Infantis, S. Enteritidis and S. Brandenburg have also been reported. In humans, several cases of salmonellosis have been linked to the consumption of raw or undercooked pork and pork products. Among the main serovars of porcine origin detected in confirmed human cases, S. Typhimurium, the monophasic variant S. 4,[5],12:i:- and S. Derby are certainly the most important.
Topics: Animals; Europe; European Union; Food Microbiology; Humans; Salmonella; Salmonella Food Poisoning; Salmonella Infections, Animal; Swine; Swine Diseases
PubMed: 28241896
DOI: 10.1017/S095026881700036X