Test 2- Enterobacteriaceae Flashcards
Enterobacteriaceae
- Reside in the GI tract of humans and animals
- Benefits Microbial antagonism
- Breakdown and absorption of the food
- Waste processing
- Vitamin K production
Is enterobacteriacea gram positive or negative?
Negative!
Thus it has Lipid A =Endotoxin
LPS
General Enterobacteriacae
- Gram-negative
- Facultative anaerobic because they live in the intestines
- Rods or coccobacilli
- Oxidase negative (except Plesiomonas, shigelloids)
Present in water, soil environment and the GI tract of humans and animals (not really environmental bacteria) Coliform bacteria
Lactose positive bacteria which includes: E. coli, Klebsiella, Enterobacter
Coliform enumeration is performed to evaluate faecal/sewage contamination- CHECK FOR SLAUGHTER PROCESS
(Enterococci are a better indicator of health risk in salt and fresh water. Enterococci are more species specific, and thus allows detection of source of contamination)
Species of Enterobactericase
- Escherichia
- Salmonella
- Yersinia
- Shigella
- Klebsiella
- • Proteus*
- • Enterobacter*
- • Citrobacter*
- • Serratia*
- more containtaments*
Opportunistic pathogens
• Klebsiella pneumonia • Klebsiella oxytoca • Enterobacter cloacae • Enterobacter aerogenes • Proteus mirabilis • Citrobacter freundii
The most common nosocomial infections/ health care ass. infections in ICU pts—- main importance in clinics
Escherichia coli
Lactose positive, oxidase negative, motile rods
ONLY CLINICALLY RELEVANT SPECIES
E. coli -General
- Very diverse species- labeled via morphology
- Shigella spp. are taxonomically also Escherichia
——————–Not present in animals
• Pathogenicity: strain dependent
————-Facultative pathogenic (eg. APEC)- can have but not be sick
———— Obligate pathogenic but then age dependent
- Differentiation between pathogenic and non-pathogenic strains not always evident
- Associated with
—————————–Certain serotypes (serotyping)
—————————–Virulence genes (pathotyping-virotyping)
—————————– Combinations of virulence genes- if a form of E.coli can’t adhere to the intestines
—————————– Biotype (for RPEC only)
E. coli -General • Infections
- Intestinal pathogenic strain
- Extra intestinal pathogenic strains (ExPEC)
—————- Respiratory
—————- Septicaemiae
—————- UTI
—————-Mastitis
E. coli -General • Virulence factors
- Virulence factors
- Cell associated
———– Endotoxin
———–Capsule
———– Fimbrial adhesins
———– Non-fimbrial adhesins
• Extracellular
———–Enterotoxins
———– Cytotoxins
———–Siderophores- captures iron
E. coli in pigs differentials
Typical Symptoms: diarrhea, edema, UTI, metristis/mastisits
• Bacterial diarrhea in fattening pigs, sows and boar
———- Brachyspira hyodysenteriae
———-Brachyspira pilosicoli
- Lawsonia intracellularis
- Salmonella (non host specific)
- Watery diarrhea
- neonatal/ 2-4wks/weaning
- Adhesion factors (small intestine)
- F4 (K88); F5 (K99); F6 (987P); F18; F41
- Enterotoxins (on plasmids)
- LT (heat labile)
- Sta, STb, EAST1 (heat stable)
E. coli disease in pigs: ETEC Adhesion factors (small intestine)
THIS ARE IMPORTANT FOR VACCINES!
• F4 (K88)- MOST IMPORTANT
——— F4: F4a,b; F4a,c; F4a,d (on plasmids)
———Specific receptor breeding of receptor free pigs; age depended presence- ONLY IN PIGS
———Mannose resistant
———Genes expressed at body Temperature, not at room Temperature
——— Solely in pigs
• F5 (K99) (on plasmids)
——— In pigs and bovines
——— Mannose resistant
———Expression Temperature dependent
——— Receptor only in very young animals: only involved in neonatal diarrhea
• F6 (987P); F18; F41
• F6 (987P) (mainly extrachromosomal)
———Neonatal
• F41 (chromosomal)
———Mannose resistant
———Pigs and bovines
———Frequently together with F5
———rare
• F18
——— See oedema disease
• Non-fimbrial adhesins
Eg. AIDA-I (adhesin involved in diffuse adherence)
E. coli disease in pigs: ETEC Enterotoxins (on plasmids) heat Labile
Enterotoxins (on plasmids)
Heat labile
- LT
- High molecular weight- STRONGER ANTIGENS
- Strong antigen
- Inactivated 30 minutes 60oC
- Activation of adenylate cyclase
- Na+ absorption
- CL- and HCO3+ secretion
Enterotoxins (on plasmids) • Heat stable
Heat stable
• STa
——— Activation of guanylate cyclase system
——— Na+ absorption DECREASES
———CL- and HCO3+ secretion- INCREASES
• STb
———Prostaglandin E2 secretion of water and electrolytes - INCREASED
——— Stimulationof5-hydrotryptaminesecretion
• EAST1 (enteroaggregative E. coli heat stable toxin)
——— Closely related to Sta
——— Also in EPEC,AEEC;VTEC- in other types of E. coli
- Low molecular weight
- Little antigenic
- Withstand 15 minutes 121oC
E. coli disease in pigs: ETEC
- Characteristics that are present most of the time: age dependent
- Neonatal ETEC
——— F5; F6; F41
——— STa; STb
———Non-hemolytic
• Neonatal till 4 weeks- RARE HEAT LABILE TOXINS
——— F4
———LT; STa; STb; EAST1
——— Hemolytic
• Weaning diarrhea
——— F4; F18
- ——– LT; STa; STb, EAST1
- ——– Hemolytic
E. coli disease in pigs: ETEC Epidemiology
• In the intestine of healthy sows
• Equilibrium between maternal immunity and infection pressure
• Break in equilibrium: disease
• Increase infection pressure
——— Low hygiene
———Presence of ETEC diseased piglets
Lowering of maternal immunity
Sow:
- MMA- leads to not enough clostriudm
- First delivery sows- lower immunity to begin with
Piglet:
——— Low birth weight
——— Other infection
———Too many piglets per sow- less clolostrium per piglet
• Appearance of new type
E. coli disease in pigs: ETEC Pathogenesis
- Ascending from lower bowel
- Oral uptake
- Small intestine
- colonization
Symptoms of E. coli in pigs
Remain drinking
Very smelly feces
Dehydration
Older animals diarrhea
- White grey
- Not as watery
E. coli disease in pigs: ETEC • Diagnosis
Detection of virulence factors
Agglutination tests- antigen and antibody clots together
PCR
E. coli disease in pigs: ETEC- Treatment and Prevention
Treatment
- Hydration (SC, IP) (PO, electrolyte solution plus glucoses and amino acids)
- Antimicrobials (susceptibility profile!- lots of resistance)
Prevention: keep infection pressure low and maternal immunity high
- Hygiene: prevention of spread
- Vaccination
——— Immunization sows
——— Inactivated vaccines: mixture of different serotypes ——— Purified adhesion factors and LT
———Two injections of which the last one 2-6 wks before partus
• Selection of receptor free piglets (F4)
E. coli disease in pigs: VTEC Oedema disease
• Oedema disease
———Post weaning
• Mixed ETEC/VTEC
———Oedema disease and diarrhea
The diarrhea is NOT caused by the VTEC– it’s generally from a mixed infection
E. coli disease in pigs: VTEC Virulence factors
• Adhesion small bowel: F18
——— Specific receptor (genetic resistance if absent)
• Exotoxin
——— VT2e or Stx2e: media necrosis
• Endotoxin: acute mortality
E. coli disease in pigs: VTEC Epidemiology and pathogenesis
- Sow to piglet
- Weaning:
——— Stress
———Change in intestinal flora
———Maternal immunity
- Excretion comes from  infection pressure is raised and thus   contamination other piglets
- Toxin production: media necrosis
——— Hyper acute: enterorrhagia
——— Acute: permeability blood vessels oedema (CNS & dyspnea)
———Slower: intravascular coagulation (CNS) •
Endotoxin: shock and acute mortality
E. coli disease in pigs: VTEC
MEDIA NECROSIS
E. coli disease in pigs: VTEC Symptoms
- < 3 wks after weaning
- Multiple piglets affected
• Clinical signs:
——— Acute mortality (some)
———Diarrhea (some)
——— Anorexia
- ——– Oedema:
- ————Hoarse voice
————- Central nervous symptoms
- ————Dyspnoea
- ———— Eye lids swollen
E. coli disease in pigs: VTEC
SWOLLEN EYELIDS
E. coli disease in pigs: VTEC Diagnosis
- Clinical signs
- Pathological findings
- Bacteriology (fecal sample)
- Confirmation: demonstration of virulence factors (PCR)
E. coli disease in pigs: VTEC treatment
Affected animals:
- Fastening- helps reestablish instential flora
- Antimicrobial therapy (note: quite some resistance, susceptibility test)
Not yet affected animals
• Antimicrobial therapy
——– Incubation time of toxin 2-3 days (so you may see still symptoms after treatment)
E. coli disease in pigs: VTEC prevention
- Reduce stress
- Feed composition
• Adaptation of intestinal flora (reduction of E. coli and toxin)
————- Probiotics
————-Organic acids (have an antibacterial effect)
————- (Zinc oxide)
—————————->2400 ppm kills E. coli
- —————————-In feed for the first 14 days after weaning
- ———— (Antimicrobials)
- ———— Vaccination (vaccine contains recombinant (non-toxic) VT2e)
• Selection of receptor (F18) negative animals
E. coli disease in pigs: EPEC
• More rare, little known about its general role
• Diarrhea at weaning
• Attaching and effacing on the enterocitis
• T3SS (needle) and injection of effector proteins
• Diagnosis:
————-Isolation + PCR (eae (intimin) gene)
E. coli disease in pigs: UTI
generals and predisposing factors
• Most important pathogen in UTI in pigs (and other mammalians)
- DD Actinobaculum suis
- E. coli infection originate most probably from intestine
• Virulence factors in pigs: ? (Research warranted)
Predisposing factors:
• Hygiene
- Water intake
- Obstipation- nutriention
- Age
- Individual (anatomical) difference
E. coli disease in pigs: UTI
Symptoms, Dx, Treatment
Symptoms
• Anorexia
- Hematuria
- Vaginal exudate
- General malaise (sometimes)
Diagnosis: Bacteriology (semi-quantitative from 103 to 105 on)
Treatment
• Culling (fertility problems)
• Antibiotics approx. 3 weeks
E. coli disease in pigs: MMA of PPDS
Etiology
- Metritis-mastitis-agalactiae( last is clostridium affected)
- Post Partum Dysgalactiae Syndrome
- Etiology
- Hereditary
- Hormonal
- Feed
- Infectious agents: E. coli, (Klebsiella spp., Enterobacter spp., Citrobacter spp.)
E. coli disease in pigs: septicaemiae
- Secondary to enteric infection
- Rarely primary
E. coli disease in bovines
• ETEC
————-Animals less than 3 days of age
• EPEC and EHEC
————-Animals older than one week
• Septicaemic
————- Neonates, lack of colostrum
E. coli disease in bovines: ETEC Symptoms
- Watery diarrhea, dehydration
- Animals less than 3 days old, NEONATES
E. coli disease in bovines: ETEC Virulence factors
• Fimbriae
————-F5 (most common)
————- F41 (freq together with F5)
————- F17 (role is not clear)
————————a, b (freq associated with CNF2), c (in association with CS31A), d
•CS31A (related to F4)
Role?
————-Freq in relation to diarrhea in older animals
- Toxins
- Sta and Stb
E. coli disease in bovines: ETEC Pathogenesis
- Oral uptake
- Multiplication
- Enterotoxin production
- (Secondary septicaemiae)
- Equilibrium between immunity and infection pressure
- Colostrum
———-Too late
- ———Too little
- ——— Too Low(inantibodies)
• Infection
———- Too early
———-Too high (infection pressure)
E. coli disease in bovines: ETEC Diagnosis
- ELISA
- Culture + virulence factors (Agglutination or PCR)
E. coli disease in bovines: ETEC Therapy
• sick animals
———-Separate ill animals
———- Hydration
- ——— Antibiotics
- ——————— Note: extremely high level of acquired resistance
———————- Diarrhea + fever: parenteral therapy
———————- No fever: colistin p.o.
———- NSAID (shock)
- Milking farms
- Hygiene: separate calves from mothers
• Colostrum
———- Of multi partus animals
• Antibiotics p.o. (4-5d, colistin)
- Vaccination of dams
- Antibodies p.o.
E. coli disease in bovines: EHEC and EPEC
- EPEC: eae
- EHEC: eae + VT (VT1 and/or VT2)
- Specific serotypes
- Age: 1-8 wks
- Mucoid diarrhea +/- blood
- Mainly in large intestine
- EHEC: zoonotic ( eg. O157:H7,…) HUS
- Therapy: antibiotics
E. coli disease in bovines: mastitis
- No virulence factors known
- DD Gram + / Gram – infection:
- ———Gram -: with fever
- ———Frequently lost udder quarter
- Prevention: hygiene
- Treatment: systemic antibiotics
E. coli disease in bovines: septicaemiae Virulence factors
- ExPEC
- Facultative pathogenic (freq. in intestinal tract)
- Virulence factors:
- Serum resistance
- Iron uptake systems
- Endotoxin
- Capsule
- Adhesion factors (P, F17, AfaE-VIII, CS31A)
• CNF1, CNF2 toxins
E. coli disease in bovines: septicaemiae Pathogenesis
in intestinal tract
Uptake either by mouth or umbilicial cord
per os goes to lymphoid tissues
IF THE COW HAS HAD ENOUGH COLOSTRUM, THEN IT can help with the E. coli.
slower with organ localization
E. coli disease in bovines: septicaemiae
Dx, therapy, and prevention
Diagnosis
• Clinical (age, symptoms, colostrum: low gamma globulins in serum)
• Isolation + PCR for virulence genes
Therapy
• NSAID (Shock)
- Antibiotics (susceptibility testing!)
- Gamma globulins: plasma from older animals
Prevention
• Colostrum
E. coli disease in cats and dogs Enteric
• Isolation from feces: significance???
- Dog
- Freq + other pathogens (Parvo, C. perfringens, parasites)
- ETEC, EPEC, VTEC, EIEC: Both in clinically heathy as well as diarrheic
- Pups: CNF1 E. coli: association with diarrhea and septicaemiae?
- Cat???
E. coli disease in cats and dogs Cystitis and Pyometra
• Cystitis
- Dog
- Fimbriae: type one, F12, F13 (associated with human UTI)
• Specific serotypes (O2, O4, O6, O83) • 50%α-hemolytic
- Cat
- Seldom (high osmolarity of urine is antibacterial)
• Pyometra (dog) same strains as cystitis
E. coli disease in poultry and other birds
• Most important bacterial disease in broilers and layers
- Facultative pathogen
- Normal E. coli flora contains approx. 10% pathogenic serotypes
Specific serotypes
• Most frequent; O1, O2, O78
- Virulence factors
- Not fully understood what is of importance
E. coli disease in poultry and other birds
clinical appearances
- Clinical appearances:
- Neonatal colibacillosis
- Respiratory colibacillosis & septicaemiae
- Peritonitis (layers)
- Coli granuloma (old backyard chickens)
- Otitis media (part of swollen head syndrome)
• Chronic respiratory colibacillosis + arthritis
Pathogenesis E. coli disease in poultry and other birds
- Peritonitis in layers:
- Endogenic infection
- Start of lay- good time to start monitoring
- Chronic form in older animals
E. coli disease in poultry and other birds Diagnosis
Diagnosis
• Pathological lesions
• Isolation of E. coli from different internal organs (liver, spleen, lung)
DD
• Yolk rest infection (omphalitis)
—————Salmonella, Staphylococcus, Proteus, Clostridia, Pseudomonas, Enterococcus
• Acute sepsis
————— Pasteurella, Salmonella, Streptococcus, Erysipelothrix
• Coligranuloma
————— Aviary TB, tumor, chronic blackhead syndrome (turkey)
• Airsacculitis
—————CRD, NDV, IB, ORT, aspergillosis
E. coli disease in poultry and other birds Treatment and prevention
• Treatment
• Very difficult
• Antibiotics: susceptibility tests necessary
• Prevention:
• Hygiene
- Stress
- Temperature
- Vaccine (Zoetis, Poulvac), for breeding stock immunization
Scabby hip/necrotic dermatitis (broilers)
- E. coli O78, O2
- Frequently also other bacteria
- Difficult to diagnose
—————Feathers
• Found at slaughter
• Prevention
————— Lower density of animals
E. coli disease in rabbits: RPEC
• EPEC (eae positive)
• Diagnosis:
- Clinical symptoms
- Isolation and subtyping (necessary)
- Specific sero/biotypes:
—————bio-/serogroup (1+/O109) is mainly pathogenic to suckling rabbits,
—————(3-/O15, 4+/O26, 8+O103) or less (2+/O128, 2+/O132) pathogenic to weaned rabbits
• Treatment
• Antibiotics
Pathogenesis of Neonatal colibacillosis
Containmination of: egg shell, neonate, manipulation of chicks
when the egg shell is containminated, upon cooling after lay shrinking of content
