Erysipelothrix. Listeria 9/12/2011. General. Pathogenic Listeria species. Presumptive Identification

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1 General Listeria Erysipelothrix Grampositive, nonspore forming rods Facultative anaerobes Grow over a wide temperature range (4 ºC to 44 ºC) tolerate ph (5.5 ~9.5) and 10% NaCl Widely distributed in herbage, feces of healthy animals, sewage etc Catalase (), oxidase (), H 2 S () Presumptive Identification Pathogenic Listeria species Gram stain Negative? Positive? Two pathogenic spp. in the genus:, Morphology Cocci? Bacilli? Spore formation Bacillus Positive? Negative? Catalase Positive? Negative? Sheep, cattle, goats Cattle Dogs, cats, horses Pigs Birds Sheep, cattle Encephalitis, abortion, septicemia Mastitis (rare) Abortion, encephalitis (rare) Abortion, septicemia, encephalitis Septicemia Abortion Motility Positive? Negative? Corynebacterium 1

2 : Habitat : Motility Ubiquitous in nature Capable of growth over a wide temperature range (4 ºC to 45 ºC) tolerant to high salt Primary habitat Soil, decaying vegetation (saprophyte) Animal feed, silage, water, fecal material of domestic animals, sewage, etc. Asymptomatic fecal carriers in humans and many animal species: About 1% of humans shed Motile via peritrichous flagella (< 30 ºC), but not or very weakly at 37 ºC Tumbling motility Monotrichous Lopotrichous Amphitrichous Peritrichous flagella Polar flagella Excellent! Listeria : Motility Umbrella growth in semisolid agar Listeriosis in Ruminants Ingestion of contaminated silage The organism can multiply in silage which has not been fermented properly Fermentation of silage 1. To produce more nutrients 2. Depletion of oxygen Degradation of cellulose and hemicellulose to small sugars Conversion of small sugars to lactic acids by lactic acid bacteria Reduction of ph (about 4) Low ph can kill away can enter the animal via conjunctiva, Most common the oral and nasal mucosa 2

3 Listeriosis in Ruminants Encephalitis Circling disease (may circle in one direction) in ruminants Depression, weakness, fever, incoordination, blindness, push against objects High mortality (Death in 23 days) Abortion Listeria may infect the uterus of domestic animals, especially ruminants Mother is asymptomatic and recovers completely Visceral form Occur in septicemic listeriosis Small necrotic foci may be found in any organs, especially the liver Mastitis Not common Some cases, clinically healthy cows secrete Listeria in milk Listeriosis in Humans Do not cause illness in general population Risk groups 1. Pregnant women and their unborn/newborn babies 2. Immunocompromised individuals 3. Elderly individuals Diseases GI disease, CNS disease, abortion, septicemia High mortality (1540%) Highest percentage of hospitalization among foodborne pathogens Listeriosis in Humans Listeriosis in Humans Major foodbornepathogenic bacteria in the US Pathogen Cases Hospitalizations Deaths Bacteria No. No. (%) No. (CFR*) Campylobacter 6, (14.6) 8 (0.1) Listeria (89.6) 16 (12.8) Salmonella 8,256 2,290 (27.7) 29 (0.4) Shigella 1, (18.7) 0 STEC O (41.6) 2 (0.5) STEC nono (15.3) 1 (0.2) Vibrio (23.3) 6 (3.1) Yersinia (32.7) 1 (0.6) *CFR= case fatality ratio Foodbrone Disease Active Surveillance Network (FoodNet, USA, 2010) Primarily a foodborne illness: zoonotic disease Approximately 2,500 cases in the US annually resulting in 500 deaths Listeria outbreak of Maple Leaf Foods in Canada 2008: caused 23 deaths including a death in PEI 3

4 : Intracellular life Capacity to invade and multiply within host cells including macrophages InlA PLC LLO Soft ice cream Internalin (InlA): host cell invasion Listeriolysin O (LLO): a cholesteroldependent poreforming toxin Phospholipase C (PLC): escape from vesicle ActA: mediate actin polymerization PLC LLO ActA Actin rockets Doublemembraned vesicle Biophys. J. Rafelski and Theriot 89: 2146 Actin tail staining (infected macrophage) Listeriosis Diagnosis and Treatment Diagnosis 1. Specimens: brain, aborted placenta and fetus 2. Listeriosis is confirmed by isolation of Listeria can be enriched by incubating 4ºC: cold enrichment 3. Various selective media available in brain Vaccine 1. Avirulent live vaccines have been used in some countries with reported good protection 2. Vaccination is equivocal since the disease is too sporadic Treatment 1. Penicillin (the drug of choice), erythromycin, sulfonamide tetracycline 2. High doses are required Discontinue the use of the particular silage 4

5 Penicillin Tetracycline Listeria in milk Silage X Mastitis Soil Intestinal colonization Vegetation Different from infects wide range of animal species including humans. Almost exclusively associated with infections in ruminants, particularly sheep. Abortion, enteritis, and neonatal septicemia, but not meningoencephalitis produces a very wide zone of hemolysis Human consumption Listeria in meat or from environment Septicemia Abortion CNS infection Characterization CAMP test Species L. innocua Betahemolysis Nitrate reduction Mannitol Acid produced from Rhamnose V Xylose Virulence L. innocua Hemolysis enhancement with Staphylococcus aureus (S) Rhodococcus equi (R) L. welshimeri V L. welshimeri L. seeligeri L. seeligeri L. grayi V V : Hemolysis enhancement 5

6 CAMP test Various Commercial Kits Biochemical identification Fluorescent antibody Nucleic acid Negative Positive S. aureus R. equi NEOGEN BioControl System Microbact TM 12L MICROID Listeria Erysipelothrix rhusiopathiae Listeria Erysipelothrix Grampositive, slender rods, tend to become filamentous in old cultures Small colonies with αhemolysis 6

7 Erysipelothrix rhusiopathiae Compared with Listeria Habitat Tonsils and intestines of many animal species, especially pigs, turkeys, sheep and cattle Sewage, soil Survives for several months in animal tissues such as frozen or chilled meat, smoked ham, and dry blood Survive in swine feces for up to 6 months at <12 ºC Resists drying and remains viable in soil many months Similar to. In general, E. rhusiopathiae rods are longer Catalse Oxidase Motility βhemolysis H 2 S E. rhusiopathiae Only few Grampositive are H 2 S pos sulfursulfur reductase H 2 S iron ferric sulfide (black) Pigs Turkeys Humans Lambs E. rhusiopathiae: Diseases Route of entry is not known, but associated with wounds Three basic manifestations can occur in sequence or separately Acute: Septicemia with acute lameness, high fever, deaths Subacute: Skin form (diamond skin disease) Chronic form: Endocarditis and arthritis An important disease in turkeys Enters via fight wounds Septicemia, arthritis See more often in males Cause erysipeloid (nonsuppurative) Enter via wounds by handling infected pigs and pork, fish Polyarthritis Dolphins Fatal septicemia Erysipelas An important disease in pigs and turkeys and a sporadic disease in many other animals A disease mainly in growing pigs (>12 wks) Economic loss Fever, arthritis, and sudden death Diamondshaped skin lesions almost anywhere on the body If untreated, the lesion may become necrotic Endocarditis: bacteria within the blood system can cause heart disease Arthritis 7

8 Erysipeloid in humans E. rhusiophathiae causes: Erysipelas in swine and turkeys Erysipeloid in humans occurring on the hands of individuals who handle infected animals eg. workers on farms and in slaughterhouses, veterinarians Enlarged red or swelling Rarely serious or lifethreatening Erysipelothrix rhusiopathiae Diagnosis Clinical signs typical diamondshaped lesions Cultures organisms can be isolated from skin biopsy ELISA test Vaccination Routine in swine and turkeys Killed bacterins or attenuated vaccines Treatment: Penicillin is very effective 8