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Salmonella. Filename: Salmonella.ppt. Salmonella. Nomenclature Incidence Clinical syndromes gastroenteritis typhoid fever. 2,000 serotypes Subgroup 1 S. cholerae-suis S. typhi S. enteritidis subgroups 2-5 cold-blooded animals environment. Human Pathogens Salmonella typhi
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Salmonella Filename: Salmonella.ppt
Salmonella • Nomenclature • Incidence • Clinical syndromes • gastroenteritis • typhoid fever
2,000 serotypes Subgroup 1 S. cholerae-suis S. typhi S. enteritidis subgroups 2-5 cold-blooded animals environment Human Pathogens Salmonella typhi Salmonella paratyphi Salmonella
S. cholerae-suis: Transmission • Humans to animals • Animals to humans • Humans and animals to animal feeds Large Inoculum: 106
Incidence in Ontario 1994 1992 1991 typhoid 6 6 paratyphoid 85 152 salmonellosis 1003 639 581
Salmonella: Clinical Syndromes • Gastroenteritis • Bacteremia: followed by gastroenteritis • Enteric fever • Asymptomatic colonization
Salmonella: Gastroenteritis • incubation 6-48 hrs. • nausea, vomiting, diarrhea, fever, abdominal cramps, myalgia, headache • 2 days - 1 week: usually spontaneous resolution
Mechanism of Pathogenicity Gastroenteritis • ingestion • absorbed to brush border of epithelial cells of small intestine and colon • migrate to lamina propria, ileocaecal • multiply in lymphoid follicles • reticulendothelial hyperplasia and hypertrophy
Hyperplasia vs Hypertrophy • Hyperplasia : abnormal increases in the number of normal cells (organ swells) • Hypertrophy : increase in size of an organ
Usually caused by S. cholerae-suis S. typhi S.paratyphi S. dublin Complications osteomyelitis (10%) arthritis endocarditis Salmonella:Bacteremia Gram negative bacteremia is non-suppurative
Enteric Fever: S. typhi • ileocaecal penetration • intraluminal multiplication • mononuclear response (macrophages) • Salmonella remains alive • 2nd week - lymphoid hyperplasia (mesenteric lymph nodes) • back to bowel
S. typhi • found in stool - enteric media and selenite enrichment • high antibodies
Mechanism of Fluid Secretion Stimulation • Arachidonic acid with the enzyme cyclooxygenase stimulates the production of prostaglandin which then causes an increase in cAMP (cyclic adenosine monophosphate) and stimulates fluid secretion.
Reduction of Fluid Secretion • Anti-inflammatory drugs • aspirin - non-steroidal, anti-inflammatory • inhibits cyclo-oxygenase which is necessary to • produce prostaglandins