Salmonella Salmonella Salmonella Salmonella , major cause of - PDF document

I ntroduction I ntroduction Salmonella Salmonella • Salmonella • Salmonella , major cause of bacterial , major cause of bacterial foodborne foodborne diarrhea worldwide diarrhea worldwide • 1.4 million infections of non • 1.4 million infections of non- -typhoidal typhoidal Mehrdad Tajkarimi Tajkarimi Mehrdad Salmonella Salmonella in US each year in US each year • 100% more fatalities between 1993 • 100% more fatalities between 1993- - DVM PhD DVM PhD 2003 2003 University of California- University of California -Davis Davis • Crucial • Crucial zoonotic zoonotic agents in the agents in the veterinary field veterinary field Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 History History Salmonella infections infections Salmonella • Water and milk, vehicles of • Water and milk, vehicles of • Typhoid fever: • Typhoid fever: enteric fever, 1874 enteric fever, 1874 Caused by Salmonella Salmonella � Caused by � • S • S . . Typhi Typhi, enormous problem in , enormous problem in enterica serotype serotype Typhi Typhi enterica the US, before World War II the US, before World War II � Human Human- -specific specific � • Non • Non- -typhoid typhoid Salmonella Salmonella infections infections � Human fecal contamination Human fecal contamination � may have peaked near 1990 may have peaked near 1990 of food or water of food or water Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 Salmonella infections infections Salmonella infections infections Salmonella Salmonella • Gastroenteritis syndrome, all • Gastroenteritis syndrome, all • Enteric fever • Enteric fever — — S. S. Paratyphi Paratyphi A A other types of Salmonella Salmonella other types of S. paratyphi paratyphi B (renamed B (renamed S. S. � S. � • >2400 serotypes of • >2400 serotypes of Salmonella Salmonella Schottmuelleri) ) Schottmuelleri • 150 of them have been • 150 of them have been S. paratyphi paratyphi C (renamed C (renamed S. S. � S. � associated with human disease associated with human disease Hirshfeldii) ) Hirshfeldii Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 1

Overall symptoms of Overall symptoms of Overall symptoms of Overall symptoms of Salmonella infection Salmonella infection Salmonella infection infection Salmonella • Caused by invasion of intestinal • Caused by invasion of intestinal • Nausea and vomiting for a • mucosal cells, organism grows Nausea and vomiting for a mucosal cells, organism grows inside fixed macrophages inside fixed macrophages few hours followed by few hours followed by • I mmuno • I mmuno compromised may get compromised may get abdominal pain and diarrhea abdominal pain and diarrhea systemic infections systemic infections • Sometimes fever • Sometimes fever • Arthritis / Reuters syndrome (3 • Arthritis / Reuters syndrome (3 4 weeks ) ) – 4 weeks – Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 I nfective dose in man Salmonella Salmonella I nfective dose in man and animals and animals contamination contamination • Day old chicks 1 • Day old chicks 1 – – 5 cells 5 cells • Most human • Most human Salmonella Salmonella outbreaks, outbreaks, • Four week old 100 • consumption, products of animal consumption, products of animal Four week old 100 – – 1,000 1,000 origin origin • Adult hens • Adult hens ≥ ≥ 10,000 10,000 • Infection in humans may be • Infection in humans may be • 50 • 50 – – 60 lb pigs 60 lb pigs ≥ ≥ 10,000 10,000 transmitted during contact with transmitted during contact with • Human infants • Human infants ≤ ≤ 100 100 animals, contaminated water, or animals, contaminated water, or the environment the environment • Adult human male • Adult human male ≥ ≥ 100,000 100,000 Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 Classification of Classification of Salmonella transfer transfer Salmonella Salmonella Salmonella • Family • Family Enterobacteriaceae Enterobacteriaceae • S. • S. Enteritidis Enteritidis isolated from a sick child isolated from a sick child • Genus • Genus Salmonella Salmonella kill up to 50% of wild rat populations kill up to 50% of wild rat populations • 26% of wild rats, • • Two Species: 26% of wild rats, S. S. Enteritidis Enteritidis and/or and/or • Two Species: S. S. Typhimurium Typhimurium 1. Salmonella 1. Salmonella enterica enterica • Samples collected in five states, • Samples collected in five states, 2. 2. Salmonella Salmonella bongori bongori Salmonella isolates from 4.7% of all isolates from 4.7% of all Salmonella samples. samples. Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 2

Classification of Characteristics of Classification of Characteristics of Salmonella Salmonella Salmonella Salmonella • Serotyping based on three cell • Serotyping based on three cell- - • Gram negative • Gram negative surface antigens: surface antigens: • Aerobic or facultative anaerobic • Aerobic or facultative anaerobic 1. The O, or cell 1. The O, or cell- -wall (somatic) wall (somatic) • Motile or non • Motile or non- -motile motile antigen, antigen, • Non • Non- -spore forming rods spore forming rods 2. The H, or 2. The H, or flagellar flagellar antigen, & antigen, & • Catalase positive and • Catalase positive and oxidase oxidase 3. The Vi ( The Vi ( outer polysaccharide layer ) 3. outer polysaccharide layer ) negative antigen antigen negative Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 Characteristics of Characteristics of Growth of Salmonella Salmonella Growth of Salmonella Salmonella • Optimum water activity is 0.96 • Optimum water activity is 0.96 – – 0.999. 0.999. • • Has 90% DNA homology with Has 90% DNA homology with • Oxidation • Oxidation- -reduction (OR) potential: little reduction (OR) potential: little E. coli E. coli effect on growth or survival of effect on growth or survival of • Little or no correlation between • microorganism. microorganism. Little or no correlation between • The growth temperature between 5 • The growth temperature between 5 – – serotype and clinical signs and serotype and clinical signs and 45 45° °C with an optimum growth C with an optimum growth symptoms symptoms temperature of 35 temperature of 35 – – 37 37° °C. C. • pH values are between 4 and 9 • pH values are between 4 and 9 Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 Salmonella Salmonella Survival of Salmonella(1) Survival of Salmonella(1) • Salmonella • Salmonella can be killed by repeated can be killed by repeated freezing and thawing cycles, food freezing and thawing cycles, food quality?!!! quality?!!! Farm Processor • Heating can kill • Heating can kill Salmonella Salmonella Consumer Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 UCDavis PHR 250 04/07 3