Listeria Erysipelothrix Filename Listeria ppt 1 112202 Outline

Outline u Microbes – Corynebacterium, Listeria, Erysipelothrix u Diseases – Diphtheria, Listeriosis, Erysipeloid 2

Listeria monocytogenes short , motile, non-spore - forming, Grm + rods, - hemolytic, looks

Listeria Infections Neonatal sepsis or meningitis u Spontaneous abortion or still birth u Sepsis

Listeriosis u Disease of humans – Sepsis – Meningitis + encephalitis v 25% 6

Listeria Pathogenesis u Ingested raw contaminated food u Penetrates cell of intestine u common

Listeriosis Diagnosis u Monocytosis – Peripheral blood & cerebrospinal fluid u Gram stain –

Listeria: Virulence Factors Internalin an invasion factor controlled by the inl A gene u

Listeria: Food poisoning MILK and dairy products. This species grows at refrigerator temp. 5

Test for Listeria in Milk Add fluorescent-labelled antibodies specific for Listeria monocytogenes to milk

Listeriosis Prevention Persons at risk u avoid soft cheeses and unpasteurized milk and processed

Listeriosis Control u Hygienic food processing – contaminated vegetables – vinegar in salads u

Erysipelothrix pathogenesis u Skin lesions – fingers or hand – violet or wine coloured

Erysipelothrix rhusiopathiae u Gram positive rods u Grow aerobically – prefer 7% carbon dioxide

Erysipelothrix Epidemiology u Found in mammals, poultry & fish u Farmers, vets, slaughterhouse workers,

Erysipelothrix Diagnosis & Control u Diagnosis – Typical lesions – Occupation – Blood culture

Performance Objectives Key terms, concepts short answers 20 11/2/202

Key Organisms u Corynebacterium u Listeria u Erysipelothrix 23 11/2/202

Epidemiology of Listeriosis u Disease/bacterial factors u Transmission u Who is at risk u

u Construct Short Answers a table of the virulence factors associated with listeriosis and

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Listeria & Erysipelothrix Filename: Listeria. ppt 1 11/2/202

Outline u Microbes – Corynebacterium, Listeria, Erysipelothrix u Diseases – Diphtheria, Listeriosis, Erysipeloid 2 11/2/202

Listeriosis 3 11/2/202

Listeria monocytogenes short , motile, non-spore - forming, Grm + rods, - hemolytic, looks like Group B streptococcus but group B is catalase neg and non-motile. found in wild and domestic animals excreted into soils healthy human carriers 5 -10 % source of infection is food animal contact. 4 11/2/202

Listeria Infections Neonatal sepsis or meningitis u Spontaneous abortion or still birth u Sepsis or meningitis in immunocompromised patients u Puerperal sepsis Persons at risk: Pregnant, post partum, new born, organ transplants u 5 11/2/202

Listeriosis u Disease of humans – Sepsis – Meningitis + encephalitis v 25% 6 mortality 11/2/202

Listeria Pathogenesis u Ingested raw contaminated food u Penetrates cell of intestine u common event u most have T cells u Facultative intracellular pathogen u Immunocompromised host u Transmitted congenitally 7 11/2/202

Listeriosis Diagnosis u Monocytosis – Peripheral blood & cerebrospinal fluid u Gram stain – Gram positive rods in CFS u Culture – Blood, CSF, skin lesions 8 11/2/202

Listeria: Virulence Factors Internalin an invasion factor controlled by the inl A gene u The organisms are taken into the cell by forced phagocytosis, become enclosed in a vesicle and rupture it. u Listeriolysin - alpha hemolysis hly gene. u Lecithinase - hemolysin Phospholipase u 9 11/2/202

Listeria: Food poisoning MILK and dairy products. This species grows at refrigerator temp. 5 -12 o C Isolated by cold enrichment. 10 11/2/202

Test for Listeria in Milk Add fluorescent-labelled antibodies specific for Listeria monocytogenes to milk Pass through a flow cytometer. fluid is passed through a small opening Listeria detected by a laser beam NO CULTURE NEEDED!!! 11 11/2/202

Listeriosis Prevention Persons at risk u avoid soft cheeses and unpasteurized milk and processed meat that cannot be cooked. u thoroughly cook all meats especially hot dogs – left over meat should be cooked to steaming. 12 11/2/202

Listeriosis Control u Hygienic food processing – contaminated vegetables – vinegar in salads u Antimicrobial agents – Not cephalosporins – Ampicllin + aminoglycoside – bacteriostatic 13 11/2/202

Erysipeloid 14 11/2/202

Erysipelothrix pathogenesis u Skin lesions – fingers or hand – violet or wine coloured u Occasionally septicemia – endocarditis – afebrile arthritis 15 11/2/202

Erysipelothrix rhusiopathiae u Gram positive rods u Grow aerobically – prefer 7% carbon dioxide u Non motile u Non hemolytic u Produce hydrogen sulfide 16 11/2/202

Erysipelothrix Epidemiology u Found in mammals, poultry & fish u Farmers, vets, slaughterhouse workers, fish handlers 17 11/2/202

Erysipelothrix Diagnosis & Control u Diagnosis – Typical lesions – Occupation – Blood culture if sepsis u Control – Self limiting – Penicillin if complications 18 11/2/202

The End 19 11/2/202

Performance Objectives Key terms, concepts short answers 20 11/2/202

Key Terms 21 11/2/202

Key Terms 22 11/2/202

Key Organisms u Corynebacterium u Listeria u Erysipelothrix 23 11/2/202

Key Concepts 24 11/2/202

Epidemiology of Listeriosis u Disease/bacterial factors u Transmission u Who is at risk u Geography/ season u Incidence u Modes of control 25 11/2/202

u Construct Short Answers a table of the virulence factors associated with listeriosis and the biological activity of each u Describe the clinical manifestations of listeriosis u Construct a table listing the common Corynebacteria and the associated diseases. 26 11/2/202