Exam 2 Flashcards
Coliform bacteria characteristics
- Lactose positive
- E. Coli
- Klebsiella
- Enterobacter
E. Coli general characteristics
Lactose positive, oxidase negative, motile rods
Definition of a serotype
Complete antigenic formula of an organism
Includes O-antigen, finbriae, flagella, capsule, ect
Cell associated virulence factors
Endotoxins, capsule, fimbrial adhesions, non-fimbrial adhesions,
E. coli extracellular virulence factors
Enterotoxin, cytotoxin, siderophores
E. coli -> PIGS (enterotoxic) age group and symptoms
Neonate - weanling ages
Watery diarrhea, dehydration, but will still drink, older animals will have white-grey diarrhea (not so watery), very smelly feces
E. coli -> PIGS (enterotoxic)
Adhesion factors list:
F4 , F5, F6, F18, F41, non-fimbrial adhesions
E. coli -> PIGS (enterotoxic)
Adhesion factor F4 Aka (K88)
Mannose resistant, pigs only, genes expressed at body temperature
On plasmids
E. coli -> PIGS (enterotoxic)
Adhesion factor F5 Aka (K99)
Pigs and bovine, mannose resistant, temperature dependent,
only causes neonatal diarrhea
E. coli -> PIGS (enterotoxic)
Adhesion factor F6 Aka (987P)
Mainly extrachromosomal, neonatal
E. coli -> PIGS (enterotoxic)
Adhesion factor F41
Chromosomal, mannose resistant, pigs and bovine, frequently with F5, RARE
E. coli -> PIGS (enterotoxic)
Non-fimbrial adhesions
Adhesions involved in diffuse adherence
E. coli -> PIGS Enterotoxin
LT -> heat labile
High molecular weight, strong antigen, activates adenylate cyclase, decrease Na absorption, increase CL and HCO3 secretion
E. coli -> PIGS Enterotoxic
Heat stabile list
STa, STb, EAST1
Common traits
- low molecular weight
- little antigenic
- withstand 15 minutes 121degrees Centigrade
E. coli -> PIGS Enterotoxic
Heat stable STa
Activation of guanylate cyclase system, decrease Na+ absorption, increase secretion of HCO3 and CL
E. coli -> PIGS Enterotoxic
Heat stable STb
Increase prostaglandin E2 –> secretion of water and electrolytes
Stimulation of 5-hydrotryptamine secretion
E. coli -> PIGS Enterotoxic
Heat stable EAST1 (Enteroaggregtive E. coli Heat Stable Toxin)
Closely related to STa
Also in EPEC, AEEC, VTEC
E. coli diseases in pigs: Enterotoxigenic (ETEC)
Characteristics mostly are age dependant
Neonates: F5, F6, F41, STa, STb & non-hemolytic
Neonate- 4 weeks: F4, LT, STa, STb, EAST1, hemolytic
Weanling diarrhea: F4, F18, STB, EAST1, hemolytic
E. coli in pigs epidemiology
General
E.coli can be found in the GI of healthy sows, there has to be an equilibrium between maternal immunity and infection pressure, if this equilibrium breaks there will be disease
E. coli in pigs epidemiology
How to increase infection pressure
Low hygiene
Presence of ETEC diseased piglets
Lowering maternal immunity
Appearance of a new type
E. coli in pigs epidemiology
Problems that effect pig immunity
Sow : MMA or her first delivery
Piglets: low birth weights, other infections
If a pig has too many piglets
E. coli in pigs PATHOGENESIS
Ascend from lower bowel
Oral uptake
Small intestine
Colonization
E. coli in pigs: ETEC
Diagnosis
Detection of virulence factors, agglutination tests, PCR
E. coli in pigs: ETEC
Treatment
Hydration (SQ, IP) or PO with electrolyte + glucose + AA
Antimicrobials (based on a susceptibility profile)
E. coli in pigs: ETEC
Prevention
- Keep infection pressure low and maternal immunity high
- Hygiene: prevent spread
- Vaccination: sows, inactive (different serotypes), purified adhesion factors and LT, vaccinate sows 2-6 wks b4 partus
- Selection for receptor free piglets (F4)
E. coli in pigs: VTEC -> verotoxigenic
Oedema disease - post weaning
Mixed ETEC/VTEC - Odema and diarrhea
E. coli in pigs: VTEC
Virulence factors
Adhesion small bowel: F18
Specific receptor (if absent = resistant)
Exotoxin- VT2e or Stx2e: media necrosis
Endotoxin: acute mortality
E. coli in pigs: VTEC
Epidemiology
Sow to piglet
Weaning-> stress, GI flora changes, maternal immunity
Excretion -> increased infection pressure -> contamination of others
E. coli in pigs: VTEC Toxin production (speeds)
Endotoxin
Leads to media necrosis
Hyper acute: enterorrhagia
Acute: permeability of blood vessels oedema (CNS and dyspena)
Slower: intravascular coagulation (CNS)
ENDOTOXIN: shock and acute mortality
E. coli in pigs: VTEC
Symptoms
- Less than 3 weeks after weaning
- Multiple piglets effected
- Clinical: acute mortality (some), diarrhea(some), anorexia,
oedema -> hoarse voice, CNS symptoms, dyspnoea, swollen eyelids
E. coli in pigs: VTEC
Diagnosis
Clinical signs
Pathological findings
Bacteriology
Conformation: demonstration of virulence factors (PCR)
E. coli in pigs: VTEC
Treatment
- Sick animals: fasting, antimicrobials (susceptibility testing due to resistance)
- Healthy animals: antimicrobial therapy
- incubation time of toxin 2-3 days (symptoms after treatment possible)
E. coli in pigs: VTEC
Prevention
- Reduce stress
- Feed composition
- Adapt GI flora: probiotics, organic acids, zinc oxide (2400ppm kills, put in feed for 14 days after weaning), vaccination
- Selective of receptor (F18) negative animals
E. coli in pigs: EPEC –> Enteropathigenic
More rare, little known about its general role
Diarrhea
Attaching and effacing
T3SS (needle) and injection of effector proteins
Diagnosis
- isolation + PCR (eae (intimin) gene)
E. coli diseases in pigs: UTI
- Most important pathogen in UTI in pigs (& other mammals)
- E. coli infection originated most likely from intestine
- Virulence factors in pigs? (Research)
- Predisposition factors: hygiene, water intake, obstipation, age, individual difference
E. coli diseases in pigs: UTI
Symptoms
Anorexia
Hematuria
Vaginal exudate
General malaise (sometimes)
E. coli diseases in pigs: UTI
Diagnosis
Bacteriology (semi quantitative from 10^3 - 10^5 on)
E. coli diseases in pigs: UTI
Treatment
Culling (due to fertility problems)
Antibiotics approximately 3 weeks
E. coli diseases in pigs: MMA & PPDS
- Metritis-mastitis-aglacitiae
- Post Partum Dysgalactiae Syndrome
- Etiology: hereditary, hormonal, feed, infections agents E. coli, (Klebsiella spp., Enterobacter spp., Citrobacter spp.
E. coli diseases in pigs: Septicemia
Secondary to enteric infection
Rarely primary
E. coli diseases in Bovines
ETEC: less than 3 days of age
EPEC/EHEC: animals older than one week
Septicemic: neonates, lack of colostrum
E. coli diseases in Bovines: ETEC
Symptoms
Watery diarrhea –> dehydration
Animals less than 3 days old (neonates)
E. coli diseases in Bovines: ETEC
Virulence factors
- Fimbriae: F5(most common), F41, F17(role unclear), CS31A(related to F4 frequently diarrhea in older animals)
- Toxins: STa, STb
E. coli diseases in Bovines: ETEC
Pathigenesis
Oral uptake
Multiplication
Enterotoxin production
- (secondary septicemia)
E. coli diseases in Bovines: ETEC
Effects on Pathogenesis
Equilibrium between immunity and infection pressure
Colostrum- too little, too late, too low in antibodies
Infection- to early, or to high infection pressure
E. coli diseases in Bovines: ETEC
Diagnosis
ELISA
Culture + virulence factors (agglutination or PCR)
E. coli diseases in Bovines: ETEC
Treatment
Sick:
- Separate,
- Hydration,
- Antibiotics (high resistance, diarrhea + fever: parenteral therapy, no fever: colistin PO)
- NSAID (shock)
E. coli diseases in Bovines: ETEC
Prevention
Dairy farms
- Hygiene : separate calves from mothers
- Colostrum: of multi-partus animals
- Antibiotics p.o. (4-5d, colistin)
- Vaccination of dams
- Antibodies PO
E. coli diseases in Bovines: EHEC and EPEC
EPEC: eae EHEC: eae + VT (VT1 and/or VT2) ***Zoonosis**** Specific stereotypes Age 1-8wks Mucoid diarrhea +/- blood Mainly large intestine Therapy: antibiotics
E. coli diseases in Bovines: Mastitis
No known virulence factors DD: Gram +/- -- infection -> G- has fever -> loss of quarter Prevention: hygiene Treatment: systemic antibiotics
E. coli diseases in Bovines: Septicemiae
Virulence factors
- ExPEC
- Facultative pathogenic (freq in GI tract)
- Virulence factors: serum resistance, iron uptake systems, endotoxin, capsule, adhesion factors (P, F17, AfaE-Vlll, CS31A), CNF1, CNF2 toxins
E. coli diseases in Bovines: Septicemiae
Pathogenesis
Per os
Umbilical chord
Colostrum