Module 4 (Gram-negative And Facultative Anaerobic Rods) Flashcards

1
Q

➢ These microbes constitute the major microflora of the gastrointestinal tract

➢ They have the ability to become
opportunistic microbes in almost all
species of animals

➢ Predisposition to septicemic diseases, enterotoxigenic diarrhea and edema disease

A

Escherichia

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2
Q

Species of Escherichia associated
with animal infections

A

• E. coli
• Colibacillosis of fowls
• E. coli infection of swine
(Swine Colibacillosis)
• E. coli infection of cattle
(Colibacillosis of Cattle)
• E. coli infection of lambs
(Colibacillosis of lambs)
• E. coli infection of horses
(Colibacillosis of horses)
• E. coli infection of horses
(Colibacillosis of horses)
• E. coli infection of dogs
• E. coli infection of poultry
• E. coli infection of Rabbits

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3
Q

Morphology, staining features
and cellular composition of Escherichia

A

➢ Gram-negative rods
➢ Non-spore former, some strains are capsulated
➢ Strains are motile by means of peritrichous flagella (H-antigens)
➢ Invasive strains possess capsular polysaccharides (K-antigens)
➢ K antigens inhibit attachment of the pathogen to phagocytic cells and ingestion by host cells

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4
Q

Growth characteristics of Esherichia

A

• The organism grows on all ordinary media
• Some strains are aerobes while some are facultative anaerobes
• Positive for indole, nitrate and urease
• Does not ferment sorbitol (E. coli 0157: H7)

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5
Q

Reservoir of Infection Escherichia

A

• Environment infected with fecal
materials
• Carrier animals

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6
Q

Transmission of Escherichia

A

• Feco-oral route

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7
Q

Strains of Escherichia associated with animal infections
(Diarrhea and Colibacillosis)

A
  1. Enterotoxigenic strains (ETEC) - neonatal piglets, and weanlings
  2. Entero-invasive strains (EIEC) – neonates that received inadequate amount of colostrum
  3. Enteropathogenic strains (EPEC) – diarrhea in animals with attaching and effacing lesions in the intestinal tract
  4. Enterohemorrhagic strains (EHEC)- associated with Edema and enterotoxemia and it involves release of a vasotoxin
  5. Colibacillosis of fowls- debilitation and chronic diarrhea
  6. Extra-intestinal pathogenic E. coli (ExPEC)
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8
Q

• Marked by debilitation and chronic
diarrhea
• Fulminating septicemia
• Complicated by respiratory infections
• Associated with salpingitis,
synovitis and panophthalmitis

A

Colibacillosis of fowls

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9
Q

▪ Marked by colonic malabsorption

3 Distinct manifestations
• Neonatal E. coli enteritis (1-4 days old piglets)
• Weanling enteritis (enteritis occurs shortly after weaning, entero-toxemia cases)
• Edema disease (diarrhea, associated with age, change in feed)

A

E. coli infection of swine
(Swine Colibacillosis)

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10
Q

➢ Enteric disease (white scours) in
calves during the first week life

A

E. coli infection of cattle
(Colibacillosis of Cattle)

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11
Q

• Enteric form occurs in lambs 2-8
days old
• Caused by the proliferation of
entero-pathogenic, non-invasive
strains of E. coli in the upper small intestines

A

E. coli infection of lambs
(Colibacillosis of lambs)

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12
Q

• Accounts for approximately 1% of
abortion cases
• Observed in mares and about 25%
in infected foals

A

E. coli infection of horses
(Colibacillosis of horses)

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13
Q

• Bacteremia implicated in
“fading puppy syndrome”

A

E. coli infection of dogs

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14
Q

➢E. coli is rarely implicated in avian
diarrheal diseases

A

E. coli infection of poultry

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15
Q

• Cellulitis accompanied by dysentery and high mortality

A

E. coli infection of Rabbits

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16
Q

Virulence Factors of Escherichia

A

➢ Surface structures expressed as O (somatic), K (Capsular), H (flagellar) and F (fimbrial) antigens attack complement cascade
➢ Plasmid- encoded heat-labile (LT) and heat-stable (ST) enterotoxins
➢ Edema disease toxin
➢ Vasotoxin (edema disease)
➢ Lipopolysaccharide from the outer membrane
➢ Adhesins (adherence to target cells of the GI tract)
➢ Siderophores, Shiga-like toxins (verotoxin)
➢ Cytotoxic necrotizing factors
➢ Hemolysin

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17
Q

Laboratory diagnosis of Escherichia

A

Samples: Stools

Agent identification
➢ Bacterial isolation (MacConkey, Minca medium and E media
➢ Quantification of E. coli in the small intestines
➢ ELISA for ST and LT enterotoxin
➢ DNA probes for genes encoding enterotoxins
➢ PCR specific for E. coli trait
➢ Detection of genes associated with EPEC

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18
Q

Treatment of Escherichia

A

• Apramycin
• Chloramphenicol
• Spectinomycin
• Gentamycin
• Trimethoprim-sulfamethazole
• Ceftiofur
• Correction of fluid and electrolyte imbalance

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19
Q

Prevention and Control for Escherichia

A

➢Vaccination of gilts and sows with
fimbrial K88 antigens
➢Administration of heat-inactivated
bacterins
➢Good husbandry practice

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20
Q

• These are pathogens of the
gastrointestinal tract of animals
• The species of the genus cause
some septicemic infections

A

Salmonella

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21
Q

Species of Salmonella associated with animal infections

A

➢ S. typhimurium
➢ S. agona
➢ S. dublin
➢ S. anatum
➢ S. worthington
➢ S. newport
➢ S. Abortus-equi
➢ S. Abortus-ovis
➢ S. gallinarum
➢ S. pullorum
➢ S. heidelberg
➢ S. Abortus-suis
➢ S. montevideo
➢ S. Saint-paul
➢ S. panama
➢ S. arizona

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22
Q

Morphology, staining features and
cellular composition of Salmonella

A

• Gram-negative
• Non-capsulated short rods
• With peritrichous flagella (majority of strains)
• Some carry fimbriae (S. gallinarum and S. pullorum)
• There is one capsular type (Vi, virulence) though most do not possess capsules
• LPS, O-antigens and antigenic determinants on surfaces of flagella (H-antigens) (Kauffman-White serologic classification

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23
Q

Growth characteristics of Salmonella

A

➢ Aerobic but some are facultative
anaerobes
➢ Use citrate as a carbon source
➢ Produce gas from glucose

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24
Q

Reservoir of infection of Salmonella

A

• Soil, water, vegetation and animal feeds
• GI tract of warm and cold-blooded animals
• Carrier animals

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25
Q

Transmission of Salmonella

A

➢ Feco-oral route
➢ Ingestion
➢ Through the yolk, horizontal
transmission and Argasid ticks (Pullorum and fowl typhoid)

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26
Q

Establishment of infection to
Salmonella

A

Phase I. Colonization of the Intestine
(mediated by adhesins)

Phase II. Invasion of the intestinal epithelium (inflammatory response with PMN influx and diarrhea sets in if immune response wanes)

Phase III. Stimulation of fluid exsorption

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27
Q

Diseases associated with Salmonella

A
  1. Salmonellosis in cattle
  2. Salmonellosis in swine
  3. Salmonellosis in horses
  4. Salmonellosis in dogs and cats
  5. Salmonellosis in sheep and goats
  6. Salmonellosis of poultry
    • Pullorum/Bacillary white diarrhea
    • Fowl typhoid
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28
Q

Etiologic agent/s: S. dublin, S. typhimurium, S. montevideo, S. Saint-paul

• Infect young animals (4 to 6 months old)
• Feedlot cattle are susceptible
• Septicemic in nature or limited to the GI tract
• Pneumonia is acquired hematogenously
• Abortion is common
• Decreased in milk production
• Foul smelling diarrhea
• Fever, depression, anorexia and weakness
• Death of calves in a day or two

A

Salmonellosis in cattle

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29
Q

Etiologic agent: S.Cholera-suis,S.typhimurium

• Acute, fulminating septicemia or chronic debilitating disease in feeder pigs
• Stress-associated infection
• Purplish areas on the ears, rump and abdomen
• High fever and anorexia
• Postmortem lesions (petechiae, pneumonia, thickening and necrosis of the intestinal mucosa

A

Salmonellosis in swine

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30
Q

Etiologic agent: S. Abortus-equi, S. typhimurium, S. heidelberg)

➢ Diarrhea with severe abdominal pain, septicemia and colic

A

Salmonellosis in horses

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31
Q

Etiologic agent/s: S. typhimurium,
S. panama

• Very uncommon
• Due to noso-comial infection
• Abortion, stillbirths

A

Salmonellosis in dogs and cats

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32
Q

Etiologic agent/s: S. abortus ovis, S. Dublin, S. montevideo, S. typhimurium

A

Salmonellosis in sheep and goats

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33
Q

Etiologic agent: S. pullorum, S. typhimurium, S. anatum, S. Newport

➢Fatal among chicks (first 2 wks of life)
➢Infects the embryo before egg is hatched
➢Associated with the failure of eggs to hatch
➢Death is due to septicemia

A

Pullorum/Bacillary white diarrhea

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34
Q

Etiologic agent: S. gallinarum

➢Acute septicemic disease of adult chickens
➢Paresis, anemia, wing drooping

A

Fowl typhoid

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35
Q

Clinical signs of salmonellosis in
Poultry

A

➢ Diarrhea, Septicemia, Weakness
➢ Wing drooping
➢ hyperexcitability
➢ Drowsiness
➢ Paresis and joint swellings
➢ Anemia and Hemorrhages
➢ Leukocytosis
➢ Multiple small necrotic area
➢ Enlarged spleen (PM)

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36
Q

Other disease entities caused by
Salmonella

A
  1. Paratyphoid (Infectious enteritis of pigs)
    Etiologic agent: S. typhimurium
  2. Avian Arizoonosis
    Etiologic agent: S. arizonae
  3. Paracolon infection of turkeys
    ➢maintained in turkey flock via infected eggs
    ➢Have R plasmids
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37
Q

Virulence Factors of Salmonella

A

➢ O (somatic) Antigen
➢ H (flagellar) Antigen
➢ Vi (Virulence) Antigen
➢ Invasins (sip, Salmonella invasion protein in pathogenicity islands in the chromosomes)
➢ Adhesins (fimbria encoded genes, fim; plasmid encoded
fimbriae, pef; and long polar fimbriae, lpf)
➢ Toxins (LT-like toxin with phospholipase A activity)
➢ Siderophores (removes iron from iron-binding proteins of host)
➢ Salmonella virulence plasmids (svp)
➢ RNA polymerase containing RPOs that regulate acid tolerance (survival at < 5.0 pH) LPS and Salmolysin (Sly A)

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38
Q

Laboratory diagnosis of Salmonella

A

Samples: Feces, intestinal scrapings, milk of infected cows, blood samples, spleen and bone marrow)

Preferred culture media
➢Bacterial isolation (MacConkey Agar, XLD agar, Hektoen Enteric Media, Brilliant Green Agar)
Agent

Identification
➢Determination of somatic and flagellar antigens
➢Salmonella-specific DNA probes and primers for PCR

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39
Q

Treatment for Salmonella

A

➢ Ampicillin
➢ Cirofloxacin
➢ Enrofloxacin
➢ Amikacin

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40
Q

Prevention and Control for Salmonella

A

➢Elimination of carriers
➢Proper hygiene and sanitation
➢No effective vaccines

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41
Q

➢ Large, non-motile bacteria
➢ Produce sticky colonies when plated on nutrient media
➢ Normal flora of the vestibule, urethra and clitoris
➢ Frequently encountered in infections of the respiratory, intestinal and urogenital tracts

A

KLEBSIELLA

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42
Q

Species of Klebsiella associated with animal infections

A

• K. pneumonia (Friedlander’s bacillus)
• K. ozanae
• K. rhinoscleromatis

43
Q

Morphology, staining features and
cellular composition of Klebsiella

A

• Gram-negative short plump rods with rounded ends
• Encapsulated and non-motile
• May occur singly or in pairs

44
Q

Growth characteristics of Klebsiella

A

• Grow well on ordinary media
• Ferment a number of carbohydrates
• H2S and urease producer
• Nitrites are produced from nitrates

45
Q

Reservoir of Infection Klebsiella

A

• Respiratory excretions
• Secretions in animals and man

46
Q

Transmission of Klebsiella

A

• Airborne
• Oral route
• Direct contact with carriers

47
Q

Diseases associated with Klebsiella

A
  1. Vaginal discharges
  2. Metritis, infertility and abortion
  3. Pneumonia in sheep and goats
  4. Normal flora of the vestibule, urethra and clitoris
  5. Coliform mastitis (cattle and sow)
48
Q

Etiologic agent: K. pneumonia
➢Hyperemia
➢Edema
➢Swelling of the udder
➢Reduced milk secretion

A

Coliform mastitis (cattle and sow)

49
Q

Virulence factors of Klebsiella

A

• Capsule
• Klebecins (bacteriocin)

50
Q

Laboratory diagnosis of Klebsiella

A

Samples: Nasal secretions,Milk samples, Blood and Sputum

Preferred culture media: TSA, McConkey agar, EMB and Blood Agar

Agent Identification
➢Bacterial isolation
➢PCR of a target gene
➢Serology (determines the type of antigens)

51
Q

Treatment for Klebsiella

A

➢Cephalexin
➢Kanamycin
➢Neomycin
➢Gentamycin
➢Steroids to correct acute
inflammatory symptoms

52
Q

Control and Prevention for Klebsiella

A

➢Strict hygiene and sanitation
➢Elimination of carriers

53
Q

• Inhabitants of the intestines of
mammals

A

ENTEROBACTER

54
Q

Species associated with animal
infections Enterobacter

A

• E. agglomerans (soil-borne)
• E. aerogenes (bovine strain)

55
Q

Morphology, staining features and
cellular composition of Enterobacter

A

• Gram-negative
• Small, motile organisms (peritrichous flagella)
• Non-spore forming rod

56
Q

Growth characteristics of Enterobacter

A

• Grow in ordinary media
• Facultative anaerobes
• Reduces nitrates to nitrites
• Ferments carbohydrates (glucose with acid and gas)
• Acetate as source of carbon

57
Q

Reservoir of Infection Enterobacter

A

• Animal excretions (urine, pus, feces)
• Inanimate materials (soil, sewage, water)

58
Q

Transmission of Enterobacter

A

• Immediate contact
• Oral route

59
Q

Diseases associated with
Enterobacter

A

• Septicemic conditions
• Enteric infections

60
Q

Virulence Factors of Enterobacter

A

➢Adhesins
➢Colonizing factors

61
Q

Laboratory diagnosis of Enterobacter

A

Samples: feces

Preferred culture media: MacConkey,Trypticase
Soy Agar, Brilliant Green Agar

Agent Identification
➢ Bacterial isolation
➢ PCR of genes

62
Q

Treatment for Enterobacter

A

• Penicillin
• Tetracycline

63
Q

Prevention and Control for Entrobacter

A

• Strict sanitation
• Elimination of carriers

64
Q

• Inhabit the soil, infect water,
intestinal and urinary tracts, blood,
soft tissues and lower respiratory
tracts of animals
• Motile and have a tendency to
swarm in laboratory media
(progressive surface spreading
ability)

A

PROTEUS

65
Q

Species of Proteus associated with
animal infections

A

• P. mirabilis
• P. rettgerii
• P. vulgaris

66
Q

Morphology, staining features and
cellular composition of Proteus

A

➢ Gram-negative straight rods
➢ Highly motile (peritrichous flagella)
➢ Produce a swarming growth on agar

67
Q

Growth characteristics of Proteus

A

• Ferments glucose, xylose and
sucrose
• Produces urease and hydrogen
sulfide
• Produces indole but some do not (P. mirabilis)

68
Q

Reservoir of Infection Proteus

A

• Urine
• Feces

69
Q

Transmission of Proteus

A

• Ingestion of infected material

70
Q

Diseases associated with Proteus

A

• Urinary and GI infections
(P. mirabilis-infected spayed bitches)
• Otitis externa (dogs)
• Diarrhea (dogs)

71
Q

Other pathologic entities associated with Proteus

A

• Wound infection in a dog
• Otitis externa of Dogs and Cats
• Septicemia in dogs
• Urinary and GI tract infection in dogs and cats

72
Q

Virulence Factors of Proteus

A

• Urease (histotoxic effect on the urinary epithelium)
• Proteases

73
Q

Laboratory diagnosis of Proteus

A

Samples: Feces, Pus, Urine

Agent Identification
• Bacterial isolation and identification
-Preferred culture media: EMB, MacConkey, TSI
• Urine exam
• PCR

74
Q

Treatment for Proteus

A

➢ Cephalosporin
➢ Kanamycin
➢ Penicillin
➢ Streptomycin

75
Q

Prevention and control for Proteus

A

➢ Strict hygiene and sanitation

76
Q

• Organisms are seen frequently as tiny, pleomorphic coccobacilli
• Show bipolar staining in smears

A

Pasteurella

77
Q

Species of Pasteurella associated
with animal infections

A

• P. multocida
• P. hemolytica
• P. pneumotropica
• P. urea
• P. anatipestifer

78
Q

Morphology, staining features and
cellular composition of Pasteurella

A

➢ Gram-negative bacteria
➢ Non-motile coccobacillary rods which show bipolar staining
➢ Non-piliated, non-flagellated and non-spore formers
➢ Colonies on blood agar are smooth with a characteristic
semen-like odor
➢ Many strains produce a capsular substance
➢ Capsule contains polysaccharide
➢ Organism produce adhesins and cell wall consists of LPS and proteins

79
Q

Growth characteristics of Pasteurella

A

• Grows best in serum and blood
• Facultative anaerobes
• Ferments carbohydrates

80
Q

Reservoir of Pasteurella

A

• Mucus membranes of susceptible hosts animals

81
Q

Transmission of Pasteurella

A

• Inhalation
• Ingestion
• Through bites and scratch wounds
• By airborne droplets
• Food and water contamination
• Direct or indirect

82
Q

Diseases associated with Pasteurella

A
  1. Hemorrhagic septicemia of cattle and buffaloes
  2. Pasteurella infection in Chickens
    (Fowl Cholera)
  3. Shipping fever
  4. Snuffles and Rabbit septicemia
83
Q

Etiologic agent: P. multocida

P. multocida serotype 6:B (Southeast Asia),
P. multocida serotype 6:B (Africa)
P. multocida serotype B2 and E (Philippines)

➢ Clinical Signs
• Fever (41-42C)
• Dysentery
• Edema (pectoral region)
• Cyanosis of the mucous membrane
• Hypersalivation
• Hemorrhages on serous surfaces (PM)
• Bloodstained fluid in the thorax and abdomen (PM)

A

Hemorrhagic septicemia of cattle and buffaloes

84
Q

➢ P. multocida
➢ Outbreaks begin in a few birds in apparently healthy flocks
➢ Route of entry: through the eyes and abrasions
➢ Vascular damage leads to hemorrhage

Clinical Signs
• Mucopurulent nasal and ocular discharges (acute cases)
• Rales and diarrhea
• Caseous lesions (chronic cases)

Necropsy findings
• Petechial of the heart
• Swollen spleen
• Reddening of the mucosa of the anterior part of the intestine

A

Pasteurella infection in Chickens
(Fowl Cholera)

85
Q

• Fibrinous pleuropneumonia/
bronchopneumonia of cattle and calves handled in stressful conditions
• Respiratory distress and fever
Etiologic agent: P. hemolytica (Manheimia
hemolytica A1)

A

Shipping fever

86
Q

• Mucopurulent rhinosinusitis
• P. multocida

Clinical signs
➢Fever
➢Sero-purulent nasal discharge
➢Difficulty in breathing
➢Mucopurulent exudates
➢Difficulty breathing, bronchopneumonia
➢Middle and inner ear infections

A

Snuffles and Rabbit septicemia

87
Q

Other diseases associated with P. multocida

A
  1. Atrophic rhinitis
    ➢ Distortion of the turbinate bones, snout and facial structures of swine
  2. Pneumonia, Shipping fever, Swine plaque (cattle, sheep, goats, swine)
    ➢ Associated with stress factors (transport, harsh climate, castration and dipping)

Clinical signs
➢Severe dyspnea, Fever
➢Soft cough, Nasal discharges
➢Ocular and nasal discharges
➢Diarrhea

  1. Ulcerative lymphangitis of horse
  2. Duck septicemic disease (infectious serositis)
  3. Blue Bag (Mastitis in Sheep)
88
Q

Virulence Factors of Pasteurella

A

➢ Heat-labile toxins
➢ Surface envelope antigen
➢ Capsule
➢ Lipopolysaccharide/Endotoxin
➢ Outer membranes proteins
➢ Leukotoxins
➢ Hyaluronidase
➢ Neuraminidase

89
Q

Laboratory diagnosis of Pasteurella

A

Samples: Tracheal aspirate, Blood, Tonsils of dead animals, serum, Lungs, spleen, air sacs, material from pneumonic lesions, milk, respiratory secretions

Preferred culture media: Blood agar

Agent identification
➢ Bacterial cultivation
➢ Smears prepared from blood, spleen and tissues of animals with septicemia
➢ PCR of Pasteurella genes

90
Q

Treatment for Pasteurella

A

• Penicillin
• Ceftiofur
• Tilmicocin
• Florfenicol

91
Q

Prevention and Control for Pasteurella

A

• Reduction of stress
• Routinary immunization
• Strict quarantine measures

92
Q

• These affect fishes, birds, rodents, primates and domestic
animals
• Implicated in plagues spreading
among people through animals via
fleas.
• Infections are clustered during
warm months affecting handlers of
rabbits, cats and coyotes

A

Yersinia

93
Q

Species of Yersinia associated with
animal infections

A

• Y. ruckeri
• Y. pseudotuberculosis
• Y. pestis
• Y. enterocolitica
• Y. intermedia
• Y. frederiksenii
• Y. kristensenii
• Y. aldovae
• Y. rhodei
• Y. mollaretti
• Y. bercovieri

94
Q

Morphology, staining features and
cellular composition of Yersinia

A

➢ Gram-negative coccobacilli
➢ Pleomorphic microbes in chains
➢ Non-capsulated but flagellated (ambient temperatures)
➢ Show bipolar staining
➢ Microbes possess invasion locus proteins (AiL) and invasion (Inv) proteins

95
Q

Growth characteristics of Yersinia

A

➢ Grows on ordinary laboratory media (MacConkey)
➢ Ferments glucose
➢ Produces urease

96
Q

Reservoir Hosts of Yersinia

A

• Birds and soil

97
Q

Transmission of Yersinia

A

• Ingestion of the organism
• Through fleas
• Airborne route
• Oral acquisition (predation, cannibalism and scavenging)

98
Q

Diseases associated with Yersinia

A
  1. Bubonic plaque
  2. Enteric red mouth (freshwater fishes)
99
Q

Etiologic agent: Y. pestis

• Characterized by hemorrhagic inflammatory lesions of local lymph nodes (“buboes”)
• Systemic dissemination (septicemia)
• Pneumonia is fatal
• Fleas as vectors (Rat fleas/Xenopsylla cheopis)

Clinical Signs
• Regional lymphadenitis
• CNS involvement
• Fever, depression, anorexia, sneezing, coughing

A

Bubonic plaque

100
Q

• Hemorrhagic inflammation of peri-oral subcutis

A

Enteric red mouth (freshwater fishes)

101
Q

Virulence factors of Yersinia

A

• Yersinia adhesin proteins (Yad A) (resist activity of complement)
• Virulence proteins (Plasmid-encoded)
• Yersinia outer membrane proteins
• Yersinia protein kinase (Ypk A) (inhibits phagocytosis and oxidative burst)
• Coagulase
• Exotoxin

102
Q

Laboratory diagnosis of Yersinia

A

Samples: Lymph nodes, cerebrospinal fluid, transtracheal aspirates, blood

Agent identification
• Bacterial Cultivation
Preferred culture media: Deoxycholate – citrate medium)

• Serologic tests (hemagglutination, hemagglutination-inhibition)

• Animal inoculation (guinea pigs or mice) die in 3 to 8 days

• PCR for Yersinia genes

103
Q

Treatment for Yersinia

A

• Aminoglycosides
• Fluoroquinolones
• Chloramphenicol
• Tetracycline

104
Q

Control and prevention for Yersinia

A

• Rat proofing of buildings
• Cyanide fumigation
• Flea elimination and rodent control