The Genus Aeromonas, Plesiomonas and Vibrio

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The Genus Aeromonas, Plesiomonas and Vibrio Channarong Rodkhum D.V.M. (Hons), Ph.D. Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University Veterinary Microbiology (3110-301) Academic year 2009

Transcript of The Genus Aeromonas, Plesiomonas and Vibrio

Page 2: The Genus Aeromonas, Plesiomonas and Vibrio

Actinobacillus spp.

Gram Negative Rod (Bacilli)

Oxidase

Positive Variable Negative

Growth on MacConkey Growth on MacConkey Growth on MacConkey

Presumptive identification of aerbic gram-negative rod (Bacilli). LF, lactose Fermentor; NLF, non-lactose fermentor

Positive Negative Negative Positive Negative Positive

LF NLF

NLF

LF NLF

Moraxella spp.

Aeromonas spp.

Vibrio spp.

Bordetella bronchiseptica

Pseudomonas spp.

Moraxella bovis

Mannheimia

haemolyticaPasteurella multocida

Haemophilus spp.

Brucella spp.E. coli

Klebsiella spp.

Enterobacter spp.

Citrobacter spp.

Salmonella spp.

Proteus spp.

Yersinia spp.

Edwardseilla spp.

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The genus Aeromonas, Plesiomonas and Vibrio

Characteristics

• Gram negative• Facultative anaerobic rod• Class γ- proteobacteria• Ferment glucose• Oxidase-positive• Majority motile by flagella• All are found in aquatic environments• Most diseases they cause are enteric or septicemic in nature

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Key tests for phynotypic differentiation of members of the genera Aeromonas, Plesiomonas, and Vibrio

TestTest AeromonasAeromonas PlesiomonasPlesiomonas VibrioVibrio

O129 susceptibility (150 O129 susceptibility (150 µµg)g) NegNeg PosPos PosPos

Ornithine decarboxylaseOrnithine decarboxylase(Neg)(Neg) PosPos PosPos

Arginine dihydrolaseArginine dihydrolase PosPos PosPos NegNeg

Inositol fermentationInositol fermentation NegNeg PosPos (Neg)(Neg)

Gas from glucoseGas from glucose VarVar NegNeg NegNeg

Growth in nutreint Growth in nutreint bowth without NaClbowth without NaCl PosPos PosPos (Neg)(Neg)

Neg, Negative; Pos, positive; (Pos), almost Positive; (Neg), almost negative; Var, variable

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The genus Aeromonas

Characteristics

• Family Aeromonadaceae • Gram Negative rod or coccoid• Catalase-Positive, Oxidase-positive• Reduce Nitrate to nitrite• Resistant to Vibriostatic agent O129• Most species possess flagella (except Aeromonas salmonicida isolated from fish).• Grow at 10 – 42 °C• Almost pathogenic for fish and shellfish.

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Aeromonas hydrophila Gram stain Aeromonas hydrophila colony morphology

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Epidemiology

• Many aquatic species

• Reptile

• Amphibians

• Swine, cattle, birds and marine mammals (rare)

• Zoonosis (Food-borne disease, septicemia, peritonitis, urinary tract infections)

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Pathogenicity and Pathogenesis (1)

Virulence factors

• Toxins; Shiga like toxin, hemolysins (Aerolysin)enterotoxin

• Surface proteins ; Outer membrane protein

• Surface structures ; flagella, pili

• Extracellualr degradative enzymes ; protease, metalloprotease, lipase, phospholipase

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Pathogenicity and Pathogenesis (2)

Pathogenesis

• Colonization and invasion into host organs

• release extracellular products

• Massive septicemia and toxic extracellular products of the organism

• Interfere with host blood supply and result in massive tissue necrosis

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Diseases and primary hosts of Aeromonas that are significant in Veterinary Medicine

Genus and speciesGenus and species HostsHosts DiseasesDiseasesAeomonas hydrophillaAeomonas hydrophilla FrogsFrogs Red leg diseaseRed leg disease

EelsEels Fresh water eel Fresh water eel diseasedisease

ReptilesReptiles Necrotic stomatitisNecrotic stomatitis

Cultured warmCultured warm--water water fishfish

Fin/tail rot and Fin/tail rot and hemorrhagic hemorrhagic septicemiasepticemia

HumanHuman Food poisoningFood poisoningSepticemiaSepticemiaCellulitis, peritonistisCellulitis, peritonistis

Aeromonas Aeromonas salmonicidasalmonicida spp. spp. salmonicidasalmonicida

Salmonids, Carp and Salmonids, Carp and Gold fishGold fish

FurunculosisFurunculosis(Ulcer disease)(Ulcer disease)

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Aeromonas sp. infection in frog

Frog with lesions of “ red leg”

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Clariid catfish (Clarias batrachus) with ulcerative form of haemorrhagic septicaemia caused by Aeromonas hydrophila (photo courtesy of Dr.

Kriengsag Saitanu)

Aeromonas hydrophila infection in rainbow trout with skin ulcer (photo courtesy of D. Bruno)

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A.

hydrophila infection (cellulitis of forearm) following puncture with fishing hook (photo courtesy of Dr. Haburchak)

Forearm showing bullous lesions as a result of A. hydrophila infection (photo courtesy of Dr.

Haburchak)

Leg showing Ecthyma gangrenosum (photo courtesy of Medscape)

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Diagnosis :

• Symptoms

• Culture and identification of bacteria

• Grow well on media such as nutrient agarTryptic soy agar (TSA), blood agar

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The genus PlesiomonasCharacteristics

• Family Enterobacteriaceae

• Gram Negative rod or coccoid

• Catalase-Positive, Oxidase-positive

• Reduce Nitrate to nitrite

• Susceptible to Vibriostatic agent O129

• Most strains are motile by flagella

• Most strains are found in aquatic environments

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Epidemiology

• Aquatic environments

• isolated from fresh water estuarine water, and salt water

• isolated from fresh vegetables, shellfish and intestine of healthy snakes, monkeys, mice, dogs, cats, swine, goats, raccoons, fish and ducks

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Pathogenicity and Pathogenesis (1)

Virulence factors

• Enterotoxins ; Cholera- like toxin, Shiga-like toxins

• Heat-stable enterotoxin

• Hemolysin

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Pathogenicity and Pathogenesis (2)

Pathogenesis

• Colonization and invasion into host organs

• release extracellular products

• Massive septicemia and toxic extracellular products of the organism

• Interfere with host blood supply and result in massive tissue necrosis

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• Animal diseases due to P. shigelloides have rarely been reported.

• Diarrhea in cats, septicemia in fish

• Zoonosis ; diarrhea in human (rare)

• Immunocompromised individual appear to

be more susceptible to infection

Diseases

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Diseases and primary hosts of Plesiomonas that are significant in Veterinary Medicine

Genus and speciesGenus and species HostsHosts DiseasesDiseasesPlesiomonas Plesiomonas shigelloidesshigelloides

Cultured tilapiaCultured tilapia SepticemiaSepticemia

Rainbow troutRainbow trout SepticemiaSepticemia

ReptilesReptiles SepticemiaSepticemia

Habour sealsHabour seals DiarrheaDiarrhea

catscats Diarrhea (rare)Diarrhea (rare)

HumanHuman(esp. (esp. immunocompromised)immunocompromised)

Diarrhea, neonatal Diarrhea, neonatal meningitis, cellulitis.meningitis, cellulitis.Cholecystitis, Cholecystitis, osteomyelitisosteomyelitis

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Diagnosis :

• Symptoms

• Culture and identification of bacteria

• Selective media for Plesiomonas shigelloides :

inositol-brilliant green-bile salts agar

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The genus VibrioCharacteristics

Family Vibrionaceae Proteobacteria, γ- subdivisionGram-negative, curved-rodFacultative anaerobe, ferment glucoseMotile by polar-flagellumCatalase-Positive, Oxidase-postive (except V. metschnikovii)Reduce Nitrate to nitriteSusceptible to Vibriostatic agent O129Growth of Vibrios is stimulated by NaCl (Halophilic bacterium )

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Epidemiology

• Common in marine and estuarine environments

• Can be isolated from sediment, water, shellfish, and intestinal tract of marine mammals and fish

• Can cause diseases in mammals

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General virulence factors of pathogenic Vibrio

Capsular polysaccharide

Extracellular Product- Hemolysin- Cytolysin- Protease

chromosome

plasmid

Surface antigen

LPS

Pili

Iron uptake system

Flagellum

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Diseases and primary hosts of Vibrio that are significant in Veterinary Medicine in ThailandGenus and speciesGenus and species HostsHosts DiseasesDiseasesVibrio choleraeVibrio cholerae HumanHuman CholeraCholera

V. parahaemolyticusV. parahaemolyticus HumanHuman Food poisoning Food poisoning associated with associated with seafoodseafood

V. metschnicoviiV. metschnicovii ChickensChickens Severe enteric diseaseSevere enteric disease

V. anguillarumV. anguillarum(Listonella (Listonella anguillarum)anguillarum)

Fish, eel, shrimpFish, eel, shrimp Vibriosis, hemorrhagic Vibriosis, hemorrhagic septicemiasepticemia

V. ordaliiV. ordalii fishfish Vibriosis, hemorrhagic Vibriosis, hemorrhagic septicemiasepticemia

V. alginolyticusV. alginolyticus ShrimpShrimp VibriosisVibriosis

V. haveyiV. haveyi Shrimp, fishShrimp, fish VibriosisVibriosis

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Vibriosis in fish cause by V. anguillarum

Vibriosis in Penaeus monodon cause by Vibrio alginolyticus, V. parahaemolyticus and V. anguillarum

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Diagnosis :

• Symptoms

• Culture and identification of bacteria

• Selective media for Vibrio spp. :- Thiosulfate citrate bile-salt sucrose agar (TCBS)- Growth of Vibrios is stimulated by NaCl

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Prevention and control of Vibriosis in fish with vaccination