Food Microbiology lect on Campylobacter

Campylobacter jejuni

1. Campylobacteriosis

2. Taxonomy Kingdom =  Bacteria   Phylum =  Proteobacteria Class =  Epsilon Proteobacteria   Order =  Campylobacterales   Family =  Campylobacteraceae   Genus =  Campylobacter Species =  C. jejuni

3. Introduction Genus: Campylobacter 17 species 6 sub species Major specie: Campylobacter jejuni Campylobacter coli Less frequent species: Campylobacter lari Campylobacter upsaliensis (WHO, 2018)

4. Campylobacter jejuni Gram – ve Spiral or curved rods Motile with single polar flagella Non spore forming Microaerophilic (~5% O 2 , ~10% CO 2 ) Importance Major food borne pathogen Zoonotic Most common cause of bacterial Gastroenteritis/ Campylobacteriosis in humans 4

5. Disease Symptoms Diarrhea (frequently bloody) Abdominal pain Fever Headache Nausea Vomiting Complications Arthritis, Reiter’s Syndrome Neurological disorders: Guillain-Barré syndrome Immune system attacks own nerves 40% caused by Campylobacter jejuni infection Hemolytic Uremic Syndrome Septicemia Leading to infection of nearly any organ, including appendix, abdominal cavity, heart, nervous system, etc. Respiratory paralysis 5

6. The Organism Survives in moist environments Weeks to months Some strains tolerate cold Remains viable in: Feces Milk Water Vaginal discharges Poultry litter Center for Food Security and Public Health, Iowa State University, 2012

7. History 1886 Spiral bacteria first described 1968 Campylobacter isolated from human feces 1970s Recognized as human pathogen Center for Food Security and Public Health, Iowa State University, 2012

8. Morbidity and Mortality: Humans Common cause of bacterial diarrhea in the U.S. 20 cases/100,000 people annually Approximately 100 people die each year.. Most cases go unreported or undiagnosed Estimated 1-4 million cases in U.S. yearly. Causes 5 to 14% of diarrhea worldwide Populations at risk Young children People in developing countries Immunosuppressed Center for Food Security and Public Health, Iowa State University, 2012

9. Prevalence of Disease Worldwide Leading cause of food borne illness worldwide Many countries do not have national survey programs for Campylobacteriosis ; worldwide incidence numbers do not exist Prevalent in developing countries Study by University of Lagos, Nigeria showed that in developing countries, 40-60% of children under 5 with diarrhea were positive for Campylobacter spp. Worldwide, gastroenteritis is second only to respiratory infections in causing deaths

10. Morbidity and Mortality: Humans Top five pathogens contributing to domestically acquired foodborne illness (U.S.) in 2011 Norovirus Salmonella (non-typhoidal) Clostridium perfringens Campylobacter spp. 845,024 estimated illnesses Staphylococcus aureus Center for Food Security and Public Health, Iowa State University, 2012

11. Morbidity and Mortality: Animals Asymptomatic carriage more common than enteric disease Up to 45% of cats, 75% of dogs Higher in animal shelters, pet shops, strays, rural animals High incidence in poultry Abortion in sheep 10 to 20% abortion rate Mortality low for all causes Center for Food Security and Public Health, Iowa State University, 2012

12. Risk population All warm-blooded animals can become affected. Some animals carry the disease without exhibiting symptoms Any person can become infected Children under 5 and young adults ages 15-29 are most often affected Most deaths occur among the elderly and the immune-suppressed

13. Transmission: C. jejuni Fecal-oral Direct contact Fomites Bacteria found in/on: Vaginal discharges, abortion products Undercooked meat, raw milk Mechanical vector Common housefly Center for Food Security and Public Health, Iowa State University, 2012

14. Sources of infection Poultry meat 80% of human campylobacteriosis (EFSA 2005) Raw milk Contaminated water 14 (WHO, 2018 , Kaakoush et al. 2015)

15. Infectious dose Some people infected with as few as 500 organisms while others need >10 6 CFU Incubation period: 2-4 days

16. Virulence factors Flagella- Flagellin contribute to the bacteria's motility which allows it to travel throughout the host  Chemotaxis by flagella, which includes sensing the environment and rotating the flagella accordingly to benefit the bacteria Mucin has been found to be a positive chemotaxin for C.  jejuni  which is compatible with the bacteria’s colonization of the intestine where there is abundant mucus This virulence factor would serve as a guide towards colonization for the bacteria Bile and L-fucose are also positive chemotaxins for C.  jejuni Motility and chemotaxis help lead the bacteria to its colonization site Adhesion and invasion are important virulence factors for colonizing the host's intestinal cells Adhesion is a necessary part of virulence for this bacteria because it allows  C. jejuni  to stay on the host cell long enough to cross into it Adhesion is possible through various proteins, flagella, and lipopolysaccharide Once adhered, the bacteria can be taken up by a cytoplasmic vacuole The bacteria invade the host cell barriers through the use of flagellin

17. Produces a toxin called Cytolethal Distending Toxin (CDT) CDT activity requires activation of three genes: cdtA , cdtB , and cdtC CdtB is nuclease that damages DNA and causes cell cycle arrest Causes cell death The cell death that accompanies this toxin is a reason for blood in the host’s diarrhea. This toxin is also thought to cause immunosuppression.

18. Lipopolysaccharides (LPS) in their outer membrane Plays a role in adherence as well as evading the immune system The bacteria have the ability to shift its LPS antigen composition which makes it harder for the immune system to detect the pathogen An important factor in contracting Guillians Barre syndrome from this pathogen is the sialic acid that is contained in its core oligosaccharide This compound can resemble gangliosides which can cause this neurological disease Iron acquisition Important for sustaining nutrients within the host C. jejuni  accomplishes this through using heme compounds, siderophores, and ferric iron Iron is important for electron transport, anaerobic respiration, and energy metabolism Superoxide dismutase is also one of the virulence factors for  C. jejuni  because it gets rid of the reactive oxygen species superoxide which could harm the cell's DNA or membrane factors

19. Pathogenesis

20. Diagnosis Presumptive diagnosis Microscopy Characteristic darting motility Curved or spiral rods Definitive diagnosis Fecal or (rarely) blood cultures Organism may be difficult to isolate Biochemical, antigen testing PCR, ELISA Center for Food Security and Public Health, Iowa State University, 2012

21. Laboratory diagnosis Culture media: Charcoal agar Campy cefex agar

22. Staining : Gram negative curved rods Catalase test: + Oxidase test: + Molecular - (PCR) using specie specific primers

23. Treatment Supportive care Fluid and electrolyte therapy Antibiotics Efficacy not proven for mild infections May reduce shedding Complications Guillain-Barré syndrome Requires intensive care Center for Food Security and Public Health, Iowa State University, 2012

24. Prevention in Humans Avoid unsafe foods Raw dairy products Undercooked meat Separate raw foods Good hygiene Avoid sick animals No human vaccine Center for Food Security and Public Health, Iowa State University, 2012

25. Control strategies Antibiotics -Antibiotic resistance development Vaccines Phage therapy Organic acids Probiotics Live microorganisms which when administered in ample amounts confer health benefit on the host (WHO 2002) Generally Recognized As Safe (GRAS) organism 29

26. Mechanism of action Competitive exclusion - preventing colonization of pathogens Antagonistic effect against pathogens (antimicrobial compounds such as bacteriocins) 30

27. https://www.longdom.org/open-access/lactic-acid-bacteria-benefits-selection-criteria-and-probiotic-potential-infermented-food-2329-8901-1000129.pdf Next topic