What does salmonella typhimurium attack

A bioterrorist could simply drop samples of the bacteria onto food or drinks ready to be consumed. Outbreaks of salmonella in the U. Different salmonella serotypes are found worldwide and in a variety of different environments. These locations include water, soil, insects, factory and kitchen surfaces, animal feces, and raw meats, poultry, and seafood.

The bacteria can be isolated from these sources and grown. Approximately 40, salmonellosis cases with deaths are reported yearly in the U. The number of actual cases may be 30 times higher, or more, since milder cases may not be reported or diagnosed. There are cases of typhoid fever recorded in the U. Most salmonella species infect the small intestines upon ingestion. Illness can be caused by as few as cells.

The bacteria pass through the interior lining of the small intestines and into its middle layer, causing inflammation. Overnight cultures prepared from inoculation of a single colony from a fresh plate were used for infecting mice at the mentioned dosage. Either overnight culture or subcultured bacteria were used for cell-line experiments. Briefly, the kanamycin resistance gene cassette was PCR amplified from pKD4 plasmid using specific primers which also carried sequences homologous to the flanking region of the target gene.

The knockouts were confirmed using both primers against the gene of interest as well as Kan R cassette internal primers. Michael Hensel. The murine macrophage cell line RAW A monolayer of respective cells was infected with either overnight or 0. Bacterial attachment to host cells was enhanced by centrifuging at —1, rpm for 5 min. Infected cells were lysed using 0. Fold Proliferation:. Percent invasion:. Percent invasion was calculated as: no. For immunofluorescence analysis, RAW At indicated time points post-infection, cells were washed with PBS and fixed with 3.

Post-washes, cells were then incubated with appropriate secondary antibody conjugated with fluorophores. Coverslips were mounted on a glass slide containing mounting medium. Images were analyzed using the Zen software provided by Zeiss. Two strains of mice, 4—6 weeks old were used viz. For intraperitoneal infections, mice were injected with 10 4 bacterial cells into the peritoneal cavity and dissected 3rd day post-infection.

Behavioral studies were carried out with the mice both pre and post-infection by water maze test. The dose was determined based on literature Brunner and Zeiler, and the length of treatment determined on the survival of the control group receiving placebo. The 5th day dissection was carried out to ensure proper infection of the cohort. The main comparison of bacterial burden was done between the placebo treated group and the antibiotic treated group at the end of the entire experiment.

Behavioral tests were carried out pre and post-infection as well as post-antibiotic treatment. In all the experiments, the mice were sacrificed and organs isolated under asceptic conditions. The samples were weighed, homogenized using a bead-beater and plated on Salmonella-Shigella agar to obtain the CFU burden in the organs.

In all experiments, each group contained 4—6 mice and 2—6 independent experiments were performed unless otherwise mentioned. Mouse organs were isolated aseptically and fixed with paraformaldehyde. Following dehydration, sections embedded in paraffin were obtained using a microtome. Haematoxylin-eosin staining was performed for some sections while others were processed for staining with antibody against Salmonella O antigen. DC designed and carried out all experiments.

BB helped in the cell line experiments. AR carried out animal experiments with DC. DC and DiC wrote the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Shyamala Mani is acknowledged for Neuro2a cell line. Central animal facility, IISc is acknowledged. Vani Ravikumar is acknowledged for helping with histological analysis.

Ali, G. Spectrum of neuropsychiatric complications in cases of typhoid fever. Health 2, — Bauler, T. Salmonella meningitis associated with monocyte infiltration in mice. Bollen, W. Presence of wild-type and attenuated Salmonella enterica strains in brain tissues following inoculation of mice by different routes. Brandtzaeg, P. Plasma endotoxin as a predictor of multiple organ failure and death in systemic meningococcal disease.

Brunner, H. Oral ciprofloxacin treatment for Salmonella typhimurium infection of normal and immunocompromised mice. Agents Chemother. Datsenko, K. Dewan, P. Isolated cerebellar ataxia: an early neurological complication of enteric fever. Drevets, D. Invasion of the central nervous system by intracellular bacteria. Herrera, A.

The single intranigral injection of LPS as a new model for studying the selective effects of inflammatory reactions on dopaminergic system. Huang, S. Cellular mechanisms of microbial proteins contributing to invasion of the blood-brain barrier. Inoue, H. Rinsho Shinkeigaku 35, — PubMed Abstract Google Scholar.

Jeannin, P. Outer membrane protein A OmpA : a new pathogen-associated molecular pattern that interacts with antigen presenting cells-impact on vaccine strategies. Vaccine 20 Suppl. Jin, Y. Neural route of cerebral Listeria monocytogenes murine infection: role of immune response mechanisms in controlling bacterial neuroinvasion. Johansson, S. Salmonella lipopolysaccharide LPS mediated neurodegeneration in hippocampal slice cultures.

Joshi, N. Cranial nerve palsies in typhoid fever: report of three cases. Kavaliotis, J. Non-typhoid Salmonella meningitis. Khan, N. Outer membrane protein A and cytotoxic necrotizing factor-1 use diverse signaling mechanisms for Escherichia coli K1 invasion of human brain microvascular endothelial cells. Khosla, S. Neuro-psychiatric manifestations of typhoid. Koedel, U. Pathogenesis and pathophysiology of pneumococcal meningitis. Lancet Infect. Kumar, D. Amyloid-beta peptide protects against microbial infection in mouse and worm models of Alzheimer's disease.

Liu, B. Systemic infusion of naloxone reduces degeneration of rat substantia nigral dopaminergic neurons induced by intranigral injection of lipopolysaccharide. Lutterloh, E. Multidrug-resistant typhoid fever with neurologic findings on the Malawi-Mozambique border. Majowicz, S. The global burden of nontyphoidal Salmonella gastroenteritis. Marathe, S. Chemically, it attracts phagocytes, white blood cells that kill bad bacteria. Salmonella has the ability to punch through the tight links of cells that make up the intestinal wall, using an arsenal of proteins and toxins it can inject into cells.

Sun said scientists always thought AvrA was one of these, but, as her team reported June 4 in the online journal PloS One , AvrA actually has an opposite function. The study found that AvrA can maintain the tight structure of cell junctions in the intestinal cells, she said. AvrA temporarily stops salmonella from breaking apart the cell links.

Because the bug doesn't damage tissue during this phase, there's no inflammatory response. Instead, salmonella is mostly left alone, free to grow and multiply into a formidable invasion force. Only then does it break through the intestinal walls, beginning its reign of terror and making you sick.