Gram negatives (non-Enterobacteriaceae) Flashcards
Bordetella - morphology + metabolism + pathogenic spp.
Gram - rods
Obligate aerobes
B. bronchiseptica = canine infectious tracheobronchitis/atrophic rhinitis (po)
B. avium = contagious rhinotracheitis (turkey coryza)
Canine infectious tracheobronchitis - VFs (5)
Adhesion proteins (haemagglutinin, peractin, fimbriae) = cilial attachment Fe-binding proteins = multiplication in tissues Tracheal cytotoxin = impairs cilia LPS = inflammatory response Adenylate cyclase = inhibits phag
Canine infectious tracheobronchitis - host factors (2)
Coinfection w respiratory viruses (parainfluenza, CAD2)/Mycoplasma
Prior ciliary damage facilitates adhesion (viruses, ↑ gas env)
Inf predisposes to further infections
Canine infectious tracheobronchitis - agent + + source of inf + pathogenesis
Bordetella bronchiseptica
Inf via aerosol inhalation (from other dogs)
> attach to tracheal cilia w adhesion proteins
> Multiply locally (Fe-scavenging from host)
> inflamm response + impaired ciliary function + impaired phagocytosis
> exudate accumulates = predispose to secondary inf
> cough
> recovery ± persistent shedding
Atrophic rhinitis (pigs) - agent + pathogenesis
Bordetella bronchiseptica
Pathogenesis as for canine infectious tracheobronchitis
+ dermonecrotic toxin = damages osteoblasts > impaired osteogenesis > nasal turbinate atrophy
Actinobacillus spp./disease (5) + morphology + habitat
A. lignieresii = wooden tongue in cows
A. equuli = sleepy foal disease
A. seminis = epididymitis in rams
A. suis = acute septiceamia in pig neonates
A. pleuropneumoniae = fibrinohaemorrhagic pneumonia in pigs
Gram - coccobacilli/rods
Commensals of alimentary T/RT/UGT (TF opportunistic pathogens)
Wooden tongue - pathogenesis in cows
Commensal of buccal mucosa
> oral abrasions (rough feed) allows entry
> invasion of submucosa
> chronic pyogranulomatous lesions w CT proliferation + S granules (club colonies)
Wooden tongue - dx (cows)
Demonstration of club colonies (small grey-white granules) = protective, facilitate survival
A. lignieresii in sheep - dz characteristics
Suppurate lesions in subQ areas of head/neck/nasal cavities
> extend to cranial/cervical LNs
Sleepy foal dz - agent + dz manifestation
Actinobacillus equuli
Acute septicaemia in foals
Joint ill - agent + dz manifestation
Actinobacillus equuli
Purulent nephritis/arthritis = multiple small abscesses in renal cortex
Joint ill - agent + dx
A. equuli
Culture of joint aspirate/renal sample
Epididymitis in rams - agents (2)
Actinobacillus seminis (commensal of lower UGT > ascending UTI) Brucella ovis
Acute septicaemia in pigs - agent + host
Actinobacillus suis
1-8wk old pigs
Fibrinohaemorrhagic pneumonia in pigs - agent + habitat
Actinoacillus pleuropneumoniae
- only Actinobacillus spp. not commensal
Fibrinohaemorrhagic pneumonia in pigs - source of infection + route of transmission
Source = other infected pigs (carriers/dz’d)
Route = inhalation of infectious aerosols
Fibrinohaemorrhagic pneumonia in pigs - pathogensis
Inhalation of infectious aerosol
> adhere to alveolar epithelium (fimbriae)
> multiply in lung (Fe-scavenging)
> Inflamm response to LPS
> avoids phagocytosis (capsule)
> leucocidal cytotoxins (RTX) destroy WBCs
> fibrinohaemorrhagic vasculitis (LPS) + pulmonary necrosis (thrombosis) + sequestration/abscessation
> death, survival > carrier state
Actinobacillus pleuropneumonia - environmental factors (5)
Geographical serovar distribution
Pigs affected w waning maternal Ab (3mo)
Close contact + comingling age groups = ↑ transmission
Stress (poor ventilation/cold T) important
Herd immunity important (↓ dz severity)
Actinobacillus pleuropneumonia - immunity
Anti-Apx toxin Ab (cytotoxins) is protective
Herd immunity/colostral immunity important
Carrier state after recovery = reservoir of infection
Pasteurella multocida - associated dz’s + hosts
Haemorrhagic septicaemia in cattle
Acute fowl cholera (birds)
Bronchopneumonia
Atrophic rhinitis (w B. bronchiseptica) in pigs
Opportunistic infections (incl bite wounds)
Pasteurella multocida - immunity
Capsular Ab
Pasteurella morphology
Gram - rod
Pasteurella - source of infection
Carrier/clinically affected animals
Epizootic haemorrhagic septiceamia in cattle - agent + source of infection + host factors (1)
P. multocida
Reservoir = carrier cattle (in nasopharyngeal region)
Dz precipitated by stress (transport)
Epizootic haemorrhagic septicaemia - pathogenesis
Inhalation of aerosols/contact w URT secretions
> adhere to pharyngeal mucosa (fimbriae)
> resists phagocytosis (capsule)
> rapid multiplication/invasion of blood
> septicaemia + LPS causing haemorrhage/DIC
Shipping fever complex in cattle - agent + dz characteristics
Mannheima haemolytica
- Fibrinous pleuropneumonia
Pasteurella trehalosi - dz + host
Septicaemia in feeder lambs
Bovine shipping fever complex - pathogensis
Mannheima haemolytica = commensal of nasal/oral epithelium
> Stress (transport, crowding etc.)
> colonisation of LRT + multiplication
> Inflamm response (LPS/capsule)
> Impaired WBC function (RTX leukotoxin)
> WBC destruction = accum of inflamm exudate/fibrin/cells
> acute fibrinonecrotic bronchopneumona + pleurisy
> secondary infection follows
Moraxella - morphology, metabolism, habitiat, disease
Gram neg rods
Obligate aerobes
Obligate parasites of mucous membranes
M. bovis = infectious bovine keratooconjunctivitis (IBK, pinkeye)
Infectious bovine keratoconjunctivitis (IBK) - agent + source of infection
Moraxella bovis
Source = other infected animals (↑ contagious)
IBK - VFs (2)
Pili = adhesion to ocular epithelial cells Haemolysin = establishment + invasion
IBK - agent + pathogenesis
Moraxella bovis
> inf via contact w conjunctival/nasopharyngeal secretions
> adheres to cornea (pili)
> invades conjunctiva + cornea (haemolysin)
> multiplies locally = inflamm + ulceration
> inflamm response (neut’s) = lysosomal enzymes = further necrosis
> shed in conjunctival discharge
> healing (2-6wks)
IBK - environmental factors (2)
↑ prev in warm months = UV/flies/dust causes dmg to cornea
Intercurrent viral infection common
IBK - clin signs (3)
Photophobia
Conjunctivitis w corneal oedema/haziness
Corneal ulceration
IBK - immunity (4)
Bos indicus less susceptible (hooded eyelids)
Young (<3yo) > old = lack of acquired immunity
Recovery = resistance
Local + systemic Ab + CMI important
Haemophilus - morphology + habitat + source of infection
Gram neg coccobacilli
Obligate parasites of RT/UGT
Endogenous/exogenous origin
Infectious coryza - agent + habitat + host + origin of infection
Avibacterium paragallinarum (chickens)
- obligate parasite of mucous membranes
- Infection via chronic/healthy carriers
Infectious coryza - pathogenesis
Avibacterium paragallinarum
Inhalation of infectious aerosols
> adhesion to nasal sinus mucosa of naive bird
> acute rhinitis/sinusitis = sloughing, necrosis, oedema, inflamm
> facial swelling + discharge (shedding)
> recovery or chronic dz
Glasser’s disease (serofibrinous serositis) - agent + habitat
Haemophilus parasuis
Commensal of nasopharyngeal mucosa
Glasser’s disease (serofibrinous serositis) - pathogenesis
Susceptible pig
> invasion of nasopharyngeal mucosa (stress)
> bacteraemia
> Sepsis or localisation in serosal cavities = serofibrinous serositis
> chronic polyserositis or recovery
Thromboembolic meningoencephalitis - agent
Histophilus somnus
Thromboembolic meningoencephalitis - pathogenesis
Agent on UGT/URT mucosa > stress in feedlots > invasion + bacteraemia > localisation in meninges/brain > adheres to/dmg's ECs = platelet aggregation > thrombosis + death
Contagious equine metritis - agent + source
Taylorella equigenitalis
- obligate parasite of equine reproductive tract > STI
Contagious equine metritis - pathogenesis
Infected stallion (asymptomatic carrier in distal urethra) + susceptible mare > endometritis/cervicitis/vaginitis > mucupurulent discharge > local + systemic immuni response > recovery w carrier status > infection of susceptible stallions
Pseudomonas aeruginosa - morphology + habitat
Gram neg rod
Aerobic
Soil/water + commensal of skin/mucous membranes
Canine otitis externa + other inf’s - agent + source
Pseudomonas aeruginosa
Opportunistic pathogen following break in epithelial integrity
Also cystitis, endometritis, fleece rot, wound infections, mastitis
Pseudomoniosis - tx (4)
Polymixin
Gentamicin
Fluoroquinolones
3rd gen cephalosporins
Pseudomoniosis - VFs (4)
Pili = attachment to dmg'd epithelium Siderophores = Fe-scavenging Endotoxin (LPS)/exotoxins = systemic toxicity Mucoid capsule = antiphagocytic Slime layer = antiphagocytic
Burkholderia spp. + habitats
B. mallei = obligate parasite > glanders (eq.)
B. pseudomallei = environmental > meliodosis
Glanders - agent + manifestation + route
Burkholderia mallei
- Caseous nodules in lungs/URT/skin
- inf via inhalation/abrasion
Melioidosis - agent + manifestation + route
Burkholderia pseudomallei
- Septicaemia/pyogenic infection w abscesses in RT/CNS/viscera/LNs
- inf via ingestion, inhalation, wound contam w soil/mud/water
Brucella - morphology + habitat + spp./dz (5)
Gram neg rod
Obligate facultatively intracellular (RES) parasites
B. abortus = bovine abortion/orchitis B. melitensis = ovine abortion/orchitis B. suis = porcine abortion/orchitis B. ovis = ovine epididymitis B. canis = canine abortion/orchitis
B. abortus - VFs (2)
Infectious + invasive
Chemotactic factors for PMNs/monocytes
- intracellular survival via inh phag-lys fusion
B. abortus - host factors (4)
Intracellular in MP = chronic granulomatous rxn
Predilection for repro tract > abortions ≥ 6mo
Mature/preg cattle > young cattle
Hypersensitivity important
B. abortus - pathoenesis
Ingestion of material contam’d w vaginal discharge/aborted placenta/foetus
> penetrates intact mucous membranes
> spread via lymphatics (free/intracellular)
> regional LNs = lymphadenitis
> bacteraemia
> localisation in UGT dt growth stim factors (erythritol)
> gravid uterus (abortion) or testis/sex glands (infertility)
B. abortus - control (4)
Attenuated vaccine
Screening of milk from dairy herds
Detection of infected beef herds by serology
ID/removal of infected cattle
Undulant fever
Brucella zoonosis
- acute flu-like dz w recurrent sequelae
- hypersensitivity
Campylobacter spp. - morphology + metabolic requirements + habitat
Gram - curved rods
Microaerophilic growth
Mucosa of GIT/UBT
Campylobacter enteritis - agent + VFs (4)
Campylobacter jejuni
Adhesin = attachment to GIT mucosa
Motile (flagella)
Microaerophilic + T(opt) = 42 deg
Enterotoxin
Campy enteritis - pathogenesis
Faeco-oral infection (crowding, ↓ hygiene)
> adhere to ileal/LI mucosa (pili)
> localise in glandular crypts
> invade GI epithelial cells (T3SS)
> mild febrile enteritis
> bacteraemia
> Abortion, Guillian-Barre, recovery w shedding
Campy enteritis - immunity (1)
Local IgA prod’n important
Proliferative enteritis complex in pigs - agnet + location + PM signs
Lawsonia intracellularis
- Intracellular at apical tip of enterocytes
- Thickened mucosa + focal haemorrhage
Bovine campylobacteriosis/vibriosis - agent + disease manifestation
Campylobacter fetus venerealis
- Endometritis > temporary infertility + abortions
Bovine vibriosis - VFs (2)
Obligate parasite of bovine repro tract
Surface array proteins = antiphagocytic + Ag-varying
Bovine vibriosis - host factors (3) + route + source
Carrier status = old bulls (deep preputial crypts) + cows (poor vaginal clearance - IgA)
Immunity develops 6-12w post-inf
- Herd immunity important
Beef > dairy (natural mating)
Route = STI Source = carrier animals
Bovine vibriosis - pathogenesis
STI (from infected carrier bulls)
> inf of vagina/cervix/uterus
> endometritis
> sporadic abortions, infertility or immunity dev’s (IgA in vagina/cervix + IgG in uterus)
Bovine vibriosis - immunity (4)
Ab-mediated immobilisation/opsonisation > phagocytosis
- Uterus (IgG1) = immob + opson > agent cleared
- Vagina/cervix (IgA) = immob only > blocks opsonisation > agent persists (carrier cows)
Vax available
Abortions in sheep (epizootic) + cattle (sporadic) - agent + habitat
Campylobacter fetus fetus
Occurs in intestine/gall bladder
C. fetus fetus - outcomes of infection of non-pregnant vs pregnant (stage?) animals
Non-pregnant > sub-clinical disease
Pregnant (3rd trimester) > abortion/perinatal mortality
C. fetus fetus in ewes - pathogenesis
Faeco-oral route = inf by ingestion > intermittent bacteraemia > localisation in placenta (if 3rd trimester) > vascular/necrotic changes to placenta > abortion/perinatal mortality
C. fetus fetus - immunity
Ab-mediated immunity
C. fetus fetus - environmental factors
Faecal contam of feed/water
Aborted material = high infectious exposure > abortion storms
