共查询到20条相似文献,搜索用时 15 毫秒
1.
Background
Salmonella enterica is a facultative intracellular pathogen that replicates within a membrane-bound compartment termed Salmonella containing vacuole (SCV). The biogenesis of SCV requires Salmonella type III protein secretion/translocation system and their effector proteins which are translocated into host cells to exploit the vesicle trafficking pathways. SseF is one of these effectors required for SCV formation and Intracellular Salmonella replication through unknown mechanisms. 相似文献2.
Hao Gong Jing Su Yong Bai Lu Miao Kihoon Kim Yonghua Yang Fenyong Liu Sangwei Lu 《BMC microbiology》2009,9(1):73
Background
The type III secretion systems (T3SSs) encoded bySalmonellapathogenicity island 1 and 2 (SPI-1 and SPI-2) are important for invasion of epithelial cells during development ofSalmonella-associated enterocolitis and for replication in macrophages during systemic infection, respectively.In vitrostudies have previously revealed hierarchical transport of different SPI-1 factors and ordered synergistic/antagonistic relationships between these proteins duringSalmonellaentry. These results suggest that the level and timing of the expression of these proteins dictate the consequences of bacterial infection and pathogenesis. However, the expression of these proteins has not been extensively studiedin vivo, especially during the later stages of salmonellosis when the infection is established. 相似文献3.
Background
Salmonella Enteritidis is a highly prevalent and persistent foodborne pathogen and is therefore a leading cause of nontyphoidal gastrointestinal disease worldwide. A variety of stresses are endured throughout its infection cycle, including high concentrations of propionate (PA) within food processing systems and within the gut of infected hosts. Prolonged PA exposure experienced in such milieus may have a drastic effect on the proteome of Salmonella Enteritidis subjected to this stress. 相似文献4.
Susanna Kangas Tapani Lyytikäinen Jukka Peltola Jukka Ranta Riitta Maijala 《Acta veterinaria Scandinavica》2007,49(1):35
Background
Costs and benefits of two Salmonella control policies for broiler production were described and compared. The control options were the Zoonosis Directive 92/117/EC and the more intense strategy, the Finnish Salmonella Control Programme (FSCP). 相似文献5.
R.P. Smith V. Andres F. Martelli B. Gosling F. Marco‐Jimenez K. Vaughan M. Tchorzewska R. Davies 《Journal of applied microbiology》2018,124(1):274-285
Aims
The control of Salmonella in pig production is necessary for public and animal health, and vaccination was evaluated as a strategy to decrease pig prevalence.Methods and Results
The study examined the efficacy of a live Salmonella Typhimurium vaccine, administered to sows on eight commercial farrow‐to‐finish herds experiencing clinical salmonellosis or Salmonella carriage associated with S. Typhimurium or its monophasic variants. Results of longitudinal Salmonella sampling were compared against eight similarly selected and studied control farms. At the last visit (~14 months after the start of vaccination), when all finishing stock had been born to vaccinated sows, both faecal shedding and environmental prevalence of Salmonella substantially declined on the majority of vaccinated farms in comparison to the controls. A higher proportion of vaccine farms resolved clinical salmonellosis than controls. However, Salmonella counts in positive faeces samples were similar between nonvaccinated and vaccinated herds.Conclusions
The results suggest that maternal vaccination is a suitable option for a Salmonella Typhimurium reduction strategy in farrow‐to‐finish pig herds.Significance and Impact of the Study
Salmonella vaccines have the potential to reduce the prevalence of Salmonella in pigs and result in a reduction of human cases attributed to pork. 相似文献6.
Pietro Calderini Marta Magi Simona Gabrielli Alberto Brozzi Susanna Kumlien Goffredo Grifoni Albertina Iori Gabriella Cancrini 《BMC veterinary research》2009,5(1):1-6
Background
Feed contaminated with Salmonella spp. constitutes a risk of Salmonella infections in animals, and subsequently in the consumers of animal products. Salmonella are occasionally isolated from the feed factory environment and some clones of Salmonella persist in the factory environment for several years. One hypothesis is that biofilm formation facilitates persistence by protecting bacteria against environmental stress, e.g. disinfection. The aim of this study was to investigate the biofilm forming potential of Salmonella strains from feed- and fishmeal factories. The study included 111 Salmonella strains isolated from Norwegian feed and fish meal factories in the period 1991–2006 of serovar Agona, serovar Montevideo, serovar Senftenberg and serovar Typhimurium. 相似文献7.
Kristina Jonas Henrik Tomenius Abdul Kader Staffan Normark Ute Römling Lyubov M Belova Öjar Melefors 《BMC microbiology》2007,7(1):70
Background
Curli, cellulose and the cell surface protein BapA are matrix components in Salmonella biofilms. In this study we have investigated the roles of these components for the morphology of bacteria grown as colonies on agar plates and within a biofilm on submerged mica surfaces by applying atomic force microscopy (AFM) and light microscopy. 相似文献8.
Background
Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) is a facultative intracellular pathogen that resides within host macrophages during infection of ruminant animals. We examined survival of M. paratuberculosis infections within cultured macrophages to better understand the interplay between bacterium and host. 相似文献9.
Background
Type III secretion systems (T3SS) are essential virulence factors of most Gram-negative bacterial pathogens. T3SS deliver effector proteins directly into the cytoplasm of eukaryotic target cells and for this function, the insertion of a subset of T3SS proteins into the target cell membrane is important. These proteins form hetero-oligomeric pores acting as translocon for the delivery of effector proteins. Salmonella enterica is a facultative intracellular pathogen that uses the Salmonella Pathogenicity Island 2 (SPI2)-encoded T3SS to manipulate host cells in order to survive and proliferate within the Salmonella-containing vacuole of host cells. Previous work showed that SPI2-encoded SseB, SseC and SseD act to form the translocon of the SPI2-T3SS. 相似文献10.
Validation of a same-day real-time PCR method for screening of meat and carcass swabs for Salmonella
Charlotta L?fstr?m Michael Krause Mathilde H Josefsen Flemming Hansen Jeffrey Hoorfar 《BMC microbiology》2009,9(1):85
Background
One of the major sources of human Salmonella infections is meat. Therefore, efficient and rapid monitoring of Salmonella in the meat production chain is necessary. Validation of alternative methods is needed to prove that the performance is equal to established methods. Very few of the published PCR methods for Salmonella have been validated in collaborative studies. This study describes a validation including comparative and collaborative trials, based on the recommendations from the Nordic organization for validation of alternative microbiological methods (NordVal) of a same-day, non-commercial real-time PCR method for detection of Salmonella in meat and carcass swabs. 相似文献11.
Daniela Karasova Alena Sebkova Hana Havlickova Frantisek Sisak Jiri Volf Martin Faldyna Petra Ondrackova Vladimir Kummer Ivan Rychlik 《BMC microbiology》2010,10(1):75
Background
In this study we were interested in the colonisation and early immune response of Balb/C mice to infection with Salmonella Enteritidis and isogenic pathogenicity island free mutants. 相似文献12.
Olivier Habimana Trond Møretrø Solveig Langsrud Lene K Vestby Live L Nesse Even Heir 《BMC veterinary research》2010,6(1):48
Background
The presence of Salmonella enterica serovars in feed ingredients, products and processing facilities is a well recognized problem worldwide. In Norwegian feed factories, strict control measures are implemented to avoid establishment and spreading of Salmonella throughout the processing chain. There is limited knowledge on the presence and survival of the resident microflora in feed production plants. Information on interactions between Salmonella and other bacteria in feed production plants and how they affect survival and biofilm formation of Salmonella is also limited. The aim of this study was to identify resident microbiota found in feed production environments, and to compare the survival of resident flora strains and Salmonella to stress factors typically found in feed processing environments. Moreover, the role of dominant resident flora strains in the biofilm development of Salmonella was determined. 相似文献13.
Robert Villafane Milka Zayas Eddie B Gilcrease Andrew M Kropinski Sherwood R Casjens 《BMC microbiology》2008,8(1):227
Background
The presence of prophages has been an important variable in genetic exchange and divergence in most bacteria. This study reports the determination of the genomic sequence ofSalmonellaphage ε34, a temperate bacteriophage that was important in the early study of prophages that modify their hosts' cell surface and is of a type (P22-like) that is common inSalmonellagenomes. 相似文献14.
Background
The fliC and fljB genes in Salmonella code for the phase 1 (H1) and phase 2 (H2) flagellin respectively, the rfb cluster encodes the majority of enzymes for polysaccharide (O) antigen biosynthesis, together they determine the antigenic profile by which Salmonella are identified. Sequencing and characterisation of fliC was performed in the development of a molecular serotyping technique. 相似文献15.
Lan-Ho Chiu Cheng-Hsun Chiu Yan-Ming Horn Chien-Shun Chiou Chien-Yu Lee Chia-Ming Yeh Chang-You Yu Chean-Ping Wu Chao-Chin Chang Chishih Chu 《BMC microbiology》2010,10(1):86
Background
Salmonella are frequently isolated from chickens and their products. Prevalent serogroups and serovars of Salmonella as well as their genotypes and antibiograms were determined for cloacal samples from 1595 chickens. To understand the possible serovar and H antigens for transmission between chicken and human, serovars and their H antigens of 164 chicken and 5314 human isolates were compared. 相似文献16.
Lingyan Jiang Peisheng Wang Xiaomin Li Runxia Lv Lin Wang Bin Yang Di Huang Lu Feng Bin Liu 《Cellular microbiology》2020,22(2)
To establish systemic infections, Salmonella enterica serovar Typhimurium (S. Typhimurium) requires Salmonella pathogenicity island 2 (SPI‐2) to survive and replicate within macrophages. High expression of many SPI‐2 genes during the entire intracellular growth period within macrophages is essential, as it contributes to the formation of Salmonella‐containing vacuole and bacterial replication. However, the regulatory mechanisms underlying the sustained induction of SPI‐2 within macrophages are not fully understood. Here, we revealed a time‐dependent regulation of SPI‐2 expression mediated by a novel regulator PagR (STM2345) in response to the low Mg2+ and low phosphate (Pi) signals, which ensured the high induction of SPI‐2 during the entire intramacrophage growth period. Deletion of pagR results in reduced bacterial replication in macrophages and attenuation of systemic virulence in mice. The effects of pagR on virulence are dependent on upregulating the expression of slyA, a regulator of SPI‐2. At the early (0–4 hr) and later (after 4 hr) stage post‐infection of macrophages, pagR is induced by the low Pi via PhoB/R two‐component systems and low Mg2+ via PhoP/Q systems, respectively. Collectively, our findings revealed that the PagR‐mediated regulatory mechanism contributes to the precise and sustained activation of SPI‐2 genes within macrophages, which is essential for S. Typhimurium systemic virulence. 相似文献
17.
Background
Feed-borne spread of Salmonella spp. to pigs has been documented several times in recent years in Sweden. Experiences from the field suggest that feed-associated serotypes might be less transmittable and subsequently easier to eradicate from pig herds than other serotypes more commonly associated to pigs. Four Salmonella serotypes were selected for experimental studies in pigs in order to study transmissibility and compare possible differences between feed-assoociated (S Cubana and S Yoruba) and pig-associated serotypes (S Derby and S Typhimurium). 相似文献18.
19.
Background
The global regulatory system ArcAB controls the anaerobic growth of E. coli, however, its role in aerobic conditions is not well characterized. We have previously reported that ArcA was necessary for Salmonella to resist reactive oxygen species (ROS) in aerobic conditions. 相似文献20.
Niall De Lappe Jean O Connor Geraldine Doran Genevieve Devane Martin Cormican 《BMC microbiology》2009,9(1):155-6