3/13/2016 Learning Objectives Food 1.Use basic biochemical characteristics to identify yersinia 2.Understand what conditions in foods favor Yersinia growth Chapter 18 AN INTRODUCTION 3.Recognize,from symptoms and time of onset,a case of foodborne illness caused by yersinia Yersinia 4.Choose appropriate interventions(heat, enterocolitica her)thatpreven 5.Identify environmental sources of the organism 6.Understand the role of yersinia toxins and virulence factors in causing foodborne illness Outbreak Outbreak Brawn (head cheese)is a Yersinia serotype O:3 is the dominate traditional Christmas favorite cause of yersiniosis in US,Norway. in Norway Canada,Japan,and Europe 2006,11 patients developed March 2011,21 cases of yersiniosis yersiniosis were linked to bagged salad mix .4 hospitalized and 2 died contaminated with y.enterocolitica O:9 Pigs carry yersinia in their nasal cavities that serves as a Cases of yersiniosis are often liked to reservoir consumption of pork products Brawn contains a large amount of lard which may protect the organism during cooking
3/13/2016 1 Chapter 18 Yersinia enterocol enterocol t ca i i Learning Objectives 1. Use basic biochemical characteristics to identify Yersinia 2. Understand what conditions in foods favor Yersinia growth 3. Recognize, from symptoms and time of onset, a case of foodborne illness caused by Yersinia 4. Choose appropriate interventions (heat, preservatives, and formulations) that prevent the growth of Yersinia 5. Identify environmental sources of the organism 6. Understand the role of Yersinia toxins and virulence factors in causing foodborne illness Outbreak • Yersinia serotype O:3 is the dominate cause f i i i i US N of yersiniosis in US, Norway, Canada, Japan, and Europe • March 2011, 21 cases of yersiniosis were linked to bagged salad mix contam nated w th inated with Y. enterocol Y. enterocol t ca i i O 9: • Cases of yersiniosis are often liked to consumption of pork products Outbreak • Brawn (head cheese) is a traditional Christmas favorite in Norway • 2006, 11 patients developed yersiniosis • 4 hospitalized and 2 died • Pigs carry Yersinia in their nasal i i h l cavities that serves as a reservoir • Brawn contains a large amount of lard which may protect the organism during cooking
3/13/2016 Outbreak Outbreak June and August 1982,one of the largest outbreaks due to Yersinia Symptoms of yersinia enteritis mimic 172 culture-positive y.enterocolitica cases those of appendicitis with severe identified abdominal pain and fever 41%among children5 years of age 17 patients underwent unnecessary Pasteurized milk implicated as the mode of appendectomies transmission A similar yersinia serotype was not found in milk but was found on a milk crate on a hog farm where outdated milk was fed to hogs The milk crates if used without proper sanitation would lead to cross-contamination yersinia enterocolitica Emerged as a human pathogen in 1930s .50%DNA similarity with yersinia pseudotuberculosis and yersinia pestis -90%homology between these two pathogens y.pestis evolved from y. pseudotuberculosis some 1500 years ago
3/13/2016 2 Outbreak • June and August 1982, one of the largest outbreaks due to Yersinia • 172 culture-positive Y. enterocolitica cases identified • 41% among children < 5 years of age • Pasteurized milk implicated as the mode of transmission • A similarYersinia serotype was not found in milk but was found on a milk crate on a hog farm where outdated milk was fed to hogs • The milk crates if used without proper sanitation would lead to cross-contamination Outbreak • Symptoms of Yersinia enteritis mimic th f di iti ith those of appendicitis with severe abdominal pain and fever • 17 patients underwent unnecessary appendectomies Yersinia enterocolitica • Emerged as a human pathogen in 1930s • 50% DNA similarity with Yersinia pseudotuberculosis and Yersinia pestis - > 90% homology between these two pathogens - Y. pestis evolved from Y. pseudotuberculosis some 1500 years ago
3/13/2016 yersinia enterocolitica Yersinia characteristics characteristics Genus yersinia has 18 species y.pestis is transmitted by the bite of a Family-Enterobacteriaceae Gram-negative.oxidase-negative,rod-shaped, flea or respiratory aerosols facultative anaerobes that ferment glucose y.enterocolitica and y.pseudotuberculosis ·3 human pathogens are foodborne pathogens y.pestis causative agent of plague The 3 pathogens share a number of y.pseudotuberculosis rodent pathogen that can essential virulence determinants needed to cause disease in humans 、 overcome the host defenses y.enterocolitica intestinal pathogen and most prevalent species in human May have acquired human genes that allow 1 fish pathogen them to undermine the immune response to -y.ruckericauses enteric disease in salmonids infection Yersinia enterocolitica classification Large number of subgroups based on biochemical tests and lipopolysaccharide O-antigen Divide environmental strains from pathogenic strains No commercial rapid tests are available so identification is time consuming Serogroup O:3 is most often isolated from humans
3/13/2016 3 Yersinia enterocolitica characteristics • Genus Yersinia has 18 species • Family - Enterobacteriaceae • Gram-negative, oxidase-negative, rod-shaped, facultative anaerobes that ferment glucose • 3 human pathogens - Y. pestis causative agent of plague - Y. pseudotuberculosis rodent pathogen that can cause disease in humans - Y. enterocolitica intestinal pathogen and most prevalent species in human • 1 fish pathogen - Y. ruckeri causes enteric disease in salmonids Yersinia characteristics • Y. pestis is transmitted by the bite of a flea or resp y iratory aerosols • Y. enterocolitica and Y. pseudotuberculosis are foodborne pathogens • The 3 pathogens share a number of essential virulence determinants needed to overcome the host defenses • May have acquired human genes that allow them to undermine the immune response to infection Yersinia enterocolitica classification • Large number of subgroups based on biochemical tests and lipopolysaccharide O-antigen • Divide environmental strains from pathogenic strains • No commercial rapid tests are available so identification is time consuming • Serogroup O:3 is most often isolated from humans
3/13/2016 yersinia enterocolitica yersinia enterocolitica classification susceptibility and tolerance 18 flagellar H-antigens have been Grows at temperatures below 40c identified ·Doubling times Complete O and H serotyping is seldom -300C is about 34 min done -220C is about 1h Other schemes for serotyping -70C is about 5 h bacteriophage typing -10C is about 40 h -multienzyme electrophoresis Withstands freezing for extended periods -RFLP restriction fragment length of time polymorphisms Persists longer in cooked foods than raw plasmid DNA foods yersinia enterocolitica Yersinia enterocolitica susceptibility and tolerance susceptibility and tolerance Number of bacteria may increase a million fold on cooked pork within 24h at ·Susceptible to heat 250C or within 10 days at 70C Killed by pasteurization at 71.80C for 18 Can grow in refrigerated vacuum-packed min foods Killed by exposure to hot water 800C for Grows over a pH range of 4-10 with an 10-20min optimum pH of 7.6 Killed by ionizing radiation and sodium Acid tolerance is enhanced with by nitrite and nitrate production of urease which hydrolyzed urea to release ammonia Tolerates 5%sodium chloride
3/13/2016 4 Yersinia enterocolitica classification • 18 flagellar H-antigens have been identified • Complete O and H serotyping is seldom done • Other schemes for serotyping - bacteriophage typing - multienzyme electrophoresis - RFLP restriction fragment length polymorphisms - plasmid DNA Yersinia enterocolitica susceptibility and tolerance • Grows at temperatures below 4 O C • D gm oublin g ti mes - 30 OC is about 34 min - 22 OC is about 1 h - 7 OC is about 5 h - 1 OC is about 40 h • Withstands freezing for extended periods of time • Persists longer in cooked foods than raw foods Yersinia enterocolitica susceptibility and tolerance • Number of bacteria may increase a million fold on cooked pork within 24h at 25 OC or within 10 days at 7 O C • Can grow in refrigerated vacuum-packed foods • Grows over a pH range of 4-10 with an opti H f 7 6 timum pH of 7.6 • Acid tolerance is enhanced with by production of urease which hydrolyzed urea to release ammonia Yersinia enterocolitica susceptibility and tolerance • Susceptible to heat • Killed by pasteurization at 71.8 OC for 18 min • Killed by exposure to hot water 80 OC for 10-20 min • Killed by ionizing radiation and sodium nitrite and nitrate • Tolerates 5% sodium chloride
3/13/2016 yersinia enterocolitica yersinia enterocolitica characteristics of infection characteristics of infection Nonspecific self-limiting diarrhea Nonspecific self-limiting diarrhea May lead to a variety of autoimmune May lead to a variety of autoimmune diseases diseases such as arthritis such as arthritis Risk of these diseases is determined by Risk of these diseases is determined by host host factors such as age and immune factors such as age and immune status status Infectious dose is unknown,possible >104 CFU Infectious dose is unknown Enters the intestinal tract via contaminated Enters the intestinal tract via foods and water contaminated foods and water Stomach acid acts as a barrier to infection yersinia enterocolitica Yersinia enterocolitica characteristics of infection characteristics of infection Symptoms similar to acute appendicitis is Most symptomatic infections occur in seen in children older than 5 years and children under age of 5 adolescents causes diarrhea with low fever and pseudoappendicular syndrome abdominal pain occurs with more virulent strains -diarrhea may be watery to mucoid True appendicitis is rarely associated last from a few days to weeks or with y.enterocolitica months
3/13/2016 5 Yersinia enterocolitica characteristics of infection • Nonspecific self-limiting diarrhea • May lead to a variety of autoimmune diseases such as arthritis • Risk of these diseases is determined by host factors such as age and immune status • Infectious dose is unknown • Enters the intestinal tract via contaminated foods and water Yersinia enterocolitica characteristics of infection • Nonspecific self-limiting diarrhea • M l d f d May lead to a variety of autoimmune diseases such as arthritis • Risk of these diseases is determined by host factors such as age and immune status • Infectious dose is unknown, possible Infectious dose is unknown, possible 10 > 4 CFU • Enters the intestinal tract via contaminated foods and water • Stomach acid acts as a barrier to infection Yersinia enterocolitica characteristics of infection • Most symptomatic infections occur in children under age of 5 - causes diarrhea with low fever and abdominal pain - diarrhea may be watery to mucoid - last from a few days to weeks or months Yersinia enterocolitica characteristics of infection • Symptoms similar to acute appendicitis is seen in children older than 5 years and adolescents pseudoappendicular syndrome occurs with more virulent strains • True appendicitis is rarely associated with Y. enterocolitica