Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
208 Cards in this Set
- Front
- Back
|
staphylococci
|
"bunches of grapes"
gram +ve facultative anaerobe pyogenic non-sporing, non-motile grows on MacConkey agar opaque, creamy colonies catalase+ |
|
|
S. aureus (properties)
& S. intermedius |
haemolysis +ve
coagulase +ve DNAase +ve catalase +ve (all species) |
|
|
S. aureus (infections)
|
mastitis
necrotizing pneumonia impetigo scalded skin toxich shock syndrome osteomyelitis (dogs/chickens) endocarditis & septicaemia tick pyaemia (sheep) |
|
|
S. intermedius (infections)
|
pyodema (dogs)
|
|
|
haemolysis
|
depends on type of toxin:
alpha - narrow but complete beta - wider but incomplete |
|
|
S. hyicus
|
greasy pig disease
DNAase/catalase +ve haemolysis -ve coagulase variable |
|
|
Staphylococcal skin diseases
|
scalded skin syndrome - S. aureus (humans)
greasy pig syndrome - S. hyicus pyoderma - S. intermedius (dogs) due to exfoliative toxin (ET) |
|
|
Streptococci (properties)
|
chain-like appearnce
gram +ve facultative anaerobe translucent, greyish colonies pyogenic sensitive to bile salts catalase -ve |
|
|
Streptococci (species)
|
S. equi - strangles
S. agalactiae - mastitis S. dysgalactiae - mastitis S. uberis - mastitis S. canis - lymphadenitis S. suis - strep meningitis S. pyogenes - pharyngitis (humans) S. pneumoniae (humans) |
|
|
Streptococci (haemoloysis)
|
alpha - no (though color change)
beta - yes |
|
|
M-protein
|
antipphagocytic and anti-opsonic in Streptococci; prevents complement activation
|
|
|
bovine mastitis
|
S. aglactiaes - 1%
S. dysgalactiae - 5% S. uberis (parauberis) - 22% S. aureus - 15% E. coli - 24% |
|
|
Streptococcal mastits
|
S. agalactiae - group B(contagious)
S. dysgalactiae - group C (environmental) S. uberis - 50% E (environmental) |
|
|
Bacillus
|
gram +ve
large rods resistant spores aerobes or facultative anaerobes grow very fast majority non-pathogenic |
|
|
Bacillus (species)
|
B. anthracis (cattle/man)
B. cereus - food poisoning, eye, soft tissue B. licheniformis - sporadic abortion (cattle/sheep) |
|
|
Anthrax
|
affects all mammals
ruminants highly susceptible (rapidly fatal) pigs/horses moderately susceptible carnivores relatively resistant birds almost totally resistant |
|
|
Anthrax (epidemiology)
|
endospore formation (most impt)
endospores survive decades in soil ingestion of spores |
|
|
Anthrax (pathogenesis)
|
virulence from capsule and toxin
virulence factors on plasmids (2 - 1 for capsule / 1 for toxin) toxins = protective antigen (PA), oedema factor (EF), lethal factor (LF) |
|
|
Anthrax (oedema factor)
|
binds to PA and increases cAMP activity; inhibits neutrophil action
|
|
|
Anthrax (lethal factor)
|
stimulates macrophages to release cytokines --> decrease BP and shock
|
|
|
Anthrax (diagnosis)
|
swelling, darkening of tissue, oedema, necrosis
carcases are bloated, putrify, no rigor mortis bleeding from mouth, nostrils, anus bloods analsysis - stain with polychrome methylene blue (blue bacteria, pink capsules) colonies have "Medusa head" appearance |
|
|
Anthrax (humans)
|
3 forms:
1. cutaineous (malignant pustule) - endospores in abraded skin 2. pulmonary - 'woolsorters disease'; inhalation of spores 3. intestinal - ingestion of spores |
|
|
Clostridium
|
gram +ve
large rods resistant spores ('drumstick' spores) strict anaerobes grow very fast produce VFAs produce toxins (tetanus/botulism) antimicrobial sensitive |
|
|
Clostridium (neurotoxic species)
|
C. tetani
C. botulinum |
|
|
Clostridium (histotoxic species)
|
Cl. chauvoi (blackleg in cattle)
Cl. novyi (Black's disease in sheep) Cl. septicum (malignant oedema in cattle/pigs, brax i sheep) |
|
|
Clostridium (enterpathogenic and enterotoxaemic)
|
Cl. perfingens (types A-E)
A. nectrotic enteritis (chickens) B. lamb dysentary C. haemorrhagic enteritis (pigs), enterotoxaemia (calves), Struck (sheep) D. pulpy kidney (fat lambs), enterotoxaemia (sheep) E. Enterotoxaemia (sheep) |
|
|
Clostridium (species associated with disease)
|
C. difficile (enteritis)
C. haemolyticum (Bacillary haemoglobinuria) C. spiroforme (rabbit diahrrea) C. colinum (quail disease) |
|
|
Tetanus (C. tetani)
|
plasmid encoded toxin
neurotoxin tetanospasmin antigenically uniform (antibodies protect) infection of spore in wound (eg. castration/docking in sheep, abrasion in cows/ewes, umbilicus) |
|
|
Tetanus (pathogenesis)
|
2 chains - light (toxic) & heavy (recepor binding - releases Fragment C)
transported to CNS by intra-axonal flow site of action in terminals of inhibitor neurons blocks pre-synaptic transmission of inhibitory signals (spastic paralysis) GABA (inhibitory) release prevented |
|
|
Botulism (C. botulinum)
|
fatal intoxication by preformed neurotoxin (most potent toxin known)
environmental organism germination of spores in rotting carcases, decaying vegetation, and contaminated canned food |
|
|
Botulism (pathogenesis)
|
preformed toxin in food (ingested)
acts at neuromuscular jxn of cholinergic nerves and peripheral autonomic synapses remains at junction irreversible interference with ACh (flaccid paralysis) death from paralysis of respiratory muscles |
|
|
Tetanus and Botulism neurotoxins (comparison)
|
very similar in structure and function but act at different sites
zinc-dependent both metalloproteinases both bind at neuromuscular jxns, but TT transported via retrograde axonal transport to CNS and BT acts at peripheral cholinergic syapses |
|
|
Mycobacteria
|
gram +ve rods
aerobic acid fast (don't stain well with Gram) non-motile lipid rich cell wall(glycolipid) |
|
|
Mycobacteria (species)
|
M. tuberculosis
M. bovis (bovine TB + man, badgers, deer, pigs) M. avium sp. paratuberculosis (Johne's disease in cattle, sheep, goats, deer) M. avium sp. avium (TB in poultry and pigs) M. leprae (leprosy in man, mice, armadillos) |
|
|
mycobacteria (cell wall components: virulence factors)
|
-mycolic acids: resist phagocytosis
-sulfatides: prevent phaygocyte activation & phago-lysozome fusion -trehalose di-mycolate (cord factor): inhibit phagocyte chemotaxis -lipoarabinomannan (LAM):prevent phagocyte activation -mycosides: prevent intracellular killing & digestion -cell wall antigens -superoxide dismutase (SOD) -heat shock proteins |
|
|
mycobacteria (immunity)
|
-humoral response irrelavent
-Th1 (CMI) required to limit disease -active response: lymphocyted infiltration, central necrosis in the lesion, fibrin capsule -IFN gamma from CD4 lymphocytes activate macrophages to kill intracellular bacteria -CD8 lymphocytes become cytotoxic |
|
|
mycobacteria bovis
|
-bovine TB
-primary respiratory infection leads to tubercles in lungs or lymph nodes -closed or open lesions -spread to intestine (via sputum) & serosal surfaces -pleural lesions (Pearl's disease) -spread (blood) to liver, spleen, kideny, brain -antibiotic treatments are long term & expensive |
|
|
mycobacteria bovis (epidemiology)
|
-respiratory route: infected respiratory droplets
-badgers: cattle infected by grazing on pasture contaminated by badger urine, faeces, bronchial pus or badger urine/faeces in feeder |
|
|
mycobacteria (responses to expsure)
|
-infects, killed by immune system
-infects, lies dormant for years, infection contained, no disease (most common) -infects, lies dormant for years, reactivates, acute disease -infects, rapid acute disease, may disseminate (children, immunocompromised, HIV) |
|
|
mycobacterial infection (diagnosis)
|
-immunological (tuberculin) testing
-microscopy (Ziehl Neelsen staining) -culture (lymph node, sputum, tissue lesion, aspirates, milk) -PCR |
|
|
mycobacterium avium
|
-chicken TB
-widest host range among mycobacteria: primates, cattle, pig lesions confined to lymph nodes infections |
|
|
mycobacterium avium species
|
-mycobacterium avium paratuberculosis (Johne's)
-mycobacterium avium intracellulare |
|
|
mycobacterium avium paratuberculosis
|
-Johne's disease
-transmissible chronic & progressive enteritis -cattle, sheep, goats (NOT pigs or horses) -wight loss, severe diarrhea, emaciation, death -impaired intestinal function due to chronic inflammation -may take 6mo to 5yr for clinical signs |
|
|
mycobacterium avium paratuberculosis (pathogenesis)
|
-penetration of ileal mucosa
-phagocytosis by macrophages -inflammatory & immune response -granuloma formation -thickening of intestine, increased permeability -loss of serum protein, malabsorption -diarrhea |
|
|
mycobacteria species (cutaneous infections)
|
-mycobacterium leprae (man, primates): leprosy (cutaneous lesions & nerve damage)
-mycobacterium lepraemurium (cats, rodents): skin lesions (esp. head/tail) -mycobacterium ulcerans (man): skin nodules (granulomas) which can ulcerate |
|
|
mycobacteria (leprosy)
|
1. tuberculoid:
-little disfigurement -few organisms in well contained granulomatous lesion -low bacterial load & high cell mediated immunity 2. lepromatous: -disfigurement -nodular swellings full of bacteria) -high bacterial load & low cell mediated immunity (can't clear infection) |
|
|
gram positive rods
|
-listeria
-erysipelothrix rhusiopathia -actinomyces bovis (lumpy jaw) -actinomyces viscous (mostly dogs - also others) -nocardia brasiliensis (horse pneumonia) -nocardia otitidis-cavarium (bovine mastits) -arcanobacterium pyogenes -dermatiophilus congolensis (cattle, dog, cat, man) -corynebacterium renale (> C. cystitidis > C. pilosum) -corynebacterium pseudotuberculosis (sheep, goats, cattle - also horses, man) -rhodococcus equi (ruminants) |
|
|
listeria
|
-small gram +ve rods
-small haemolytic colonies (blood agar) -facultative anaerobe -catalase +ve -outbreaks in silage -tumbling motility (25 degrees) |
|
|
listeria (species)
|
-listeria moncytogenes (sheep: meningoencephalitis, septicaemia, abortion, pyogenic)
-listeria ivanovli (sheep: abortion, systemic infxn) |
|
|
listeria (epidemiology)
|
-common commensal (tonsils, intestine) & environ
-wide temp & pH range -predisposed by trauma, immunocompromise, hormonal alterations -releated to husbandry/management |
|
|
listeria (CAMP test)
|
-plated at right angle to S. aureus
-S. aureus potentiates listeria -creates arrow appearance where listeria meets S. aureus |
|
|
listgeria (pathogenesis)
|
1. neonatal or pregnant epithelial invasion:
-bacteraemia -neonatal septicaemia or placentits (abortion) 2. tooth loss & cutting (oral inoculation) -via trigeminal nerve to brain -meningoencephalitis ("circling disease": sheep will arch neck sideways) |
|
|
listeria (pathogenic mechanisms)
|
-facultative intracellular parasites survive in macrophages & epithelial cells
-escape phagolysozome (listeriolysin LLO) & multiply (cytoplasm) -spread laterally by actin polymerization (tails) -escape epithelium: taken up by macrophages & PMN (may kill & spreads systemicall) |
|
|
listeria (epidemiology in man)
|
-enteric listeria in animals
-contamination of carcasse, milk or food crops -human ingestion (colonization of tonsils & intestine) -asymptomatic if immunocompetent -spticaemia, meningitis, abortion if immunocompromised (neonate, elderly, pregnancy) |
|
|
Ereysipelothrix rhusiopathia
|
-commensal: widespread in animals, infects man
-mainly in pigs (also sheep, turkeys, others) -smooth & rough forms produce different diseases -acute septicaemia in pigs, turkeys (smooth) -subacute skin lesions in pigs (smooth) -chronic arthritis in sheep (rough) -endocarditis in pigs (rough) |
|
|
Ereysipelothrix (pathogenesis)
|
-entry via tonsils or cuts/abrasions (immunocompromised)
-invades neutrophils 1. urticarial form*: malaise, fever, DIC, epidermal lesions ("diamonds") 2. acute septicaemia: fever, anorexia, DIC, haemorrhage, lymphadenitis, death 3. chronic arthritis/endocarditis: peristent chronic inflammation |
|
|
actinomyces species
|
-actinomyces bovis (lumpy jaw)
-actinomyces viscous (mostly dogs - also most others) -actinomyces suis -gram +ve |
|
|
actinomyces
|
-gram +ve rods
-not motile -not spore forming -microaerophilic or anaerobic -pyogenic, granulomatous reactions ("sulphur granules") -masses of branching rods surrounded by inflammatory cells |
|
|
actinomyces bovis
|
-anaerobic (normal flora)
-thick yellow pus ("sulphur granules") -actinomycosis (lumpy jaw) -invasion through wound, rough feed, damaged mucosa -soft tissue infection -rare mastitis |
|
|
actinomyces viscosus
|
-gram +ve rods
-mainly dogs (cats, pigs, goats, cattle, horses) -fimbriae: adherence to teeth - plaque -similar lesions to nocardia -localized pyogranulomatous lesions (pus forming) -thoracic lesions (peural, pericardial fluid, lung lesions) and osteomyelitis |
|
|
actinomyces suis
|
-gram +ve rods
-mastitis in sows -initiated by teat trauma |
|
|
nocardia (species)
|
-nocardia ateroides* (s.c. infection in dogs)
-nocardia brasiliensis (horse pneumonia) -nocardia otitidis-cavarium (bovine mastitis, guinea pig ear infections) -all gram +ve |
|
|
nocardia
|
-gram +ve (filaments, rods, cocci - branching)
-acid fast -inhaled, in wound or ingested -direct haematogenous spread -extracellular (prevents phagocytosis) -chronic invasive pyogenic infections (no sulfur granules) -cutaneous, respiratory (pyothorax), and systemic (pyrexia, cough, neurological, resembles distemper) forms |
|
|
arcanobacterium pyogenes
|
-gram +ve rods
-commensals -pyogenic -nonspecific purulent lesions (often in mixed infections): summer mastitis, foot abcess in sheep/cattle -abcesses -bovine abortion -wound infection -septic arthritis -major virulence factor: pyolysin (PLO) |
|
|
dermatophilus congolensis
|
-gram +ve (filamentous, branching)
-septation of filaments: zoospores (motile) beaded, 'tram track' -epidermis only -dermatitis (cattle, dog, cat, man) -sheep: lumpy wool, strawberry foot -horse: mud fever, greasy heel, rain scald |
|
|
dermatophilus congolensis (pathogenesis)
|
-commensal/spore entry (injury/wet damage)
-colinization (keratinase production aids spread & growth) -strong host response (neutrophil & lymphocyte exudation) -epidermis only |
|
|
corynebacteria
|
-gram +ve rods (pleomorphic)
-'chinese letters' -pyogenic -commensal |
|
|
corynebacteria renale group
|
-C. renale > C. cystitidis > C. pilosum
-opportunistic (highly adapted in cattle) -cystitis, pyelonephritis, balanopsthitis -predisposing factors: pregnancy, parturition, post mating -C. cystidids in bull prepuce (STD) |
|
|
corynebacteria renale group (virulence factors)
|
-pili (adherence)
-renalin (lysis of bladder cells) -urease (makes urine alkaline to promote growth) -caesinase |
|
|
corynebacteria renale group (pathogenesis)
|
-adhere to urogenital mucosa
-stress predisposes -ascending infection (proliferation) -inflammation -cystitis/pyelonephritis |
|
|
corynebacteria pseudotuberculosis
|
-gram +ve
-caseous lymphadenitis (ulcerative lymphagnitis) in sheep, goat, cattle (horses, man) -facultative intracellular -suppurative, necrotic LN (onion) -chronic abcessation (peripheral LN) -thick (greenish) caseous exudate -direct contact (shears, dip, feeders, feed) -aeorosol transmission (congregation of sheep during shearing) |
|
|
corynebacteria (pathogenesis)
|
-enter via skin wound
-phagocytosed (facultative intracellular) -multiplies in phagolysosome, phagocyte dies -permeability increases, spreads to regional LN -abcesses (primary, secondary sites) -may become metastatic -virulence factor: toxic phospholipase D (PLD) - antichemotatic (lethal to neutrophils), complement depletion, increased vascular permeability |
|
|
rhodococcus equi
|
-gram +ve
-foals 1-3mo (swine, goats, sheep, cattle, man) -intestinal commensal (herbivores) -resistant (no penicillin) -intracellular (alveolar macrophage) -respiratory -purulent pneumonia, lympadenitis, arthritis |
|
|
enterobacteriacae
|
-gram -ve rods or coccobacilli
-motile & flagellated -facultative anaerobes -oxidase -ve -grows on MacConkey agar (not bile sensitive) |
|
|
enterobacteriacae (genera)
|
-escherichia* (E. coli)
-salmonella* -klebsiella -proteus -citrobacter -edwardsiella -yersinia -shigella (man & primates) |
|
|
enterobacteriacae (surface antigens)
|
-all species subdivided in O (somatic) and H (flagellar) antigens
-'H' antigen: flagella (protein) -'K' antigen: capsule -'O' antigen: LPS (O side chain) -'F' antigen: fimbrae/pilli (now part of K?) |
|
|
escherichia coli
|
-many strains commensals
-ferments lactose (dark pink/red on MacConkey agar) -indole +ve (flagellated, some have capsules, some beta haemolytic) -ID using API 20E |
|
|
escherichia coli (disease)
|
-neonatal & post-weaning diarrhea
-neonatal septicaemia -mastitis -UTI -oedema disease (pigs) -haemorrhagic colitis & haemolytic uraemic syndrome (man) -watery mouth (lambs) -infection of existing lesions |
|
|
escherichia coli (pathotypes)
|
-ETEC: heat labile enterotoxin (LT), heat stable enterotoxin (ST), particular finbrae
-EPEC: pathogenicity island (LEE), type III secretion systems -EHEC: as EPEC + vero toxins (VT) [shiga-like toxins (SLT)] -Septicaemia, cystitis strains: particular fimbrae & capsules, haemolysin, iron uptake systems -mastitis |
|
|
escherichia coli (extraintestinal infections)
|
-gut to blodstream/urinary tract
-almost always endogenous (from own intetinal flora): few commensals have appropriate virulence factors -virulence factors: siderophore (obtain iron), capsule, fimbrae (pili), toxins (haemolysin, CNF-1) |
|
|
escherichia coli (siderophores)
|
-enterochelin (enterobactin): produced by all strains (on c'some)
-aerobactin*: not all strains (on plasmid) -affinity for iron (en vitro): enterochelin > aerobactin -enterochelin predominantly in blood: b/c bound by serum albumen (inactivates), anti-enterochelin antibodies, lower pH affinity for iron (aerobactin > enterochelin) -therefore advantage in extraintestinal infections |
|
|
enterotoxigenic E. coli (ETEC)
|
-not invasive (does not disrupt villi)
-not inflammatory, watery diarrhea -young animals (esp. pig, cattle, sheep) -not zoonotic (host specific) -travelers diarrhea (man) -virulence multifactorial (more than 1 virulence factor) -disrupts electrolyte balance (watery diarrhea) |
|
|
escherichia coli (fimbrae/pilli - ETEC)
|
-type I fimbrae (all strains)
-fimbrae species specific (eg. K88=F4: pigs) -NOT zoonotic |
|
|
escherichia coli (heat labile LT & heat stable ST toxins)
|
-ST does not enter cell: increase cGMP (disturbs electrolyte transport and water absorption)
-LT enters cell: stimulates G-prot (gut water balance changes from net absorption to net secretion) -LT highly immunogenic |
|
|
enteropathogenic E. coli (EPEC)
|
-diarrhea in lambs, calves, piglets, puppies & children
-attaching & effacing (AE) lesion -villus is 'pedestal' on which E. coli sits -disruption of actin cytyoskeleton & loss of microvilli (direct injection of protein) -loss of absorptive surface -virulence factor: locus of enterocyte effacement (LEE) |
|
|
E. coli (ETEC) fimbrae
|
-held away by fimbrae (then secrete toxin)
-not closely adherent -ETEC = enterotoxigenic E. coli |
|
|
verotoxigenic E. coi (VTEC)
|
-cytotoxic for vero cells (en vitro)
-aka shigella-like (STEC) & entrohaemorrhagic (EHEC) -kills BV endothelia cells (inhibits protein synth: removes an adeneine residue) -oedema, haemorrhage, thrombosis |
|
|
entrohaemorrhagic E. coli (EHEC)
|
-E. coli O157:H7, eg.
-haemorrhagic colitis: sudden onset of bloody diarrhea & vomiting (little or no fever) -haemolytic uraemic syndrome (HUS): haemoytic anaemia, thrombocytopenia, renal failure (in children) -'hamburger disease' (many other foods) -EHEC resevoid: mostly intestine of cattle (does make carrier sick) -type of VTEC (E. coli O157 like EPEC with vero toxin in bacteriophage) -category 3 pathogen (very low infectious dose) |
|
|
E. coli (non-enteric infections)
|
-urinary tract infections
-mastitis -septicaemia -meningitis |
|
|
escherichia coli (oedema disease)
|
-SLT-2e/VT-2e, F18 fimbrae
-oedema of forehead, stomach, large bowel & mesentery -vero toxin but does not cause enteritis (no LEE) -not zoonotic |
|
|
pasteurellaceae family
|
-gram -ve
-haemophilus -actinobacillus -pasteurella -mannheimia group |
|
|
pasteurellaceae
|
-gram -ve
-not motile -coccobaccili (pleomorphic) -aerobic/facultatively anaerobic -oxidase & catalase +ve |
|
|
haemophilus
|
-gram -ve coccobacilli
-not motile & capable of fermenting sugars -means blood loving: needs X factor (hemin) and/or V factor (NAD) -on mucosal surfaces of animals and man (host specific) |
|
|
haemophilus (species)
|
-haemophilus paragallinarum (fowl)
-haemophilus parasuis (pigs) -haemophilus agni (now called histophilus somni - sheep) -haemophilus somnus (now called histophilus somni - cattle) -haemophilus felis (cat) |
|
|
haemophilus (virulence factors: capsule)
|
-haemophilus parasuis & haemophilus paragallinarum produce cell associated capsular polysaccharides
-protective coat to evade host defenses -serotype specific antigen -antibodies to somatic antigens (membrane proteins & LPS) may also distinguish distinct serotypes |
|
|
haemophilus paragallinarum
|
-gram -ve
-fowl coryza -mostly chickens (turkeys & pigeons resistant) -clinical signs: inflammation of the turbinates & sinus epithelium (disruption of turbinates, acute air sacculitis) -infection more severe following viral or mycoplsma infection |
|
|
haemophilus parasuis
|
-gram -ve
-respiratory disease (carried in pig nasopharynx) -fibrinous lobar pneumonia -Glasser's disease: fibrinous inflammation of serous surfaces (pericardium, pleura, peritoneum) or joints (meninges if severe) |
|
|
haemophilus somnus (now called histophilus somni)
|
-gram -ve
-cattle -TEME: weakness, fever, staggering, somnolence, dyspnoea, paralysis, sudden death -lesions: fibrinous meningitis with thrombosis & necrosis -pneumonia with pleuritis & arthritis -repro failure (endometritis, metritis or late abortion) or mastitis/vaginitis |
|
|
haemophilus (virulence factors)
|
-lipopolysccharide (LPS) & lipooligosaccharide (LOS)
-LPS (endotoxin) do not have long O side chains (unlike terobacteriacae) -lipid A on LPS is toxic part (endotoxin) -endotoxin causes inflammation -exotoxins: H. somnus produces weak haemolysin -proteases (destroys mucosal IgA), membrane proteins that bind/block IgG (Fc receptor) -host specific (only able to obtain iron from single host transferrin) |
|
|
actinobacilli
|
-gram -ve coccobacilli (pleomorphic - long filaments may occur)
-facultative anaerobes -respiratory, alimentary, & urogenital tracts (commensal or pathogens) -ferment a number of sugars & grow on MacConkey (do not need X & V factors) -carry genes for RTX haemolysis toxins -cell delicate (easily destroyed by drying or disinfectants) |
|
|
actinobacilli (species)
|
-actinobacilli lignieresii (cattle: wooden tongue; sheep: abcessation)
-actinobacilli suis (pigs: neonatal septicaemia, pneumonia, endocarditis) also horse -actinobacilli pleuropneumoniae (pigs) -actinobacilli equuuli (horses: neonatal septicaemia) -actinobacilli seminis (sheep: epididymitis) |
|
|
actinobacilli (virulence factors)
|
-capsules: only A. pleuropneumoniae & A. capsulatus
-LPS (endotoxin): all species with O side chains -only LPS of A. pleuropneumoniae causes lesions -RTX toxins (extracellular) in A. pleuropneumoniae (also others but do not cause disease) |
|
|
actinobacilli lignieresii
|
-gram -ve coccobacilli (facultative anaerobic)
-slightly sticky non-haemolytic colonies on blood agar -pink colonies on MacConkey agar -in smears of pus or granules clumps of organisms & club shaped bodies -cattle: wooden tongue & rumenitis -sheep: skin abcesses |
|
|
actinobacilli pleuropneumoniae
|
-gram -ve coccobacilli (facultative anaerobic)
-contaigious pleuropneumonia (specific to pigs) -fibrinous pleuritis & necrotizing pneumonia -lesions: consolidation & congestion, may be very haemorrhagic with necrosis -clinical signs: trembling, anorexia, dyspnea, fever, haemorrhaging from nose & mouth (death within 24hr) -12 serotypes (only 2 or 3 account for disease in a region) |
|
|
actinobacilli (diagnosis)
|
-colonies tend to be sticky & difficult to remove from plate
-A. pleruopneumoniae requires V factor and can be isolated on chocolate agar on blood agar with streak of Stphylococcus -A. lignieresii grows on blood agar with CO2 |
|
|
pasteurella
|
-gram -ve coccobacilli
-bipolar staining (looks lie safety pin) -facultative anaerobes -ferment glucose -commensals of mucosal membranes of respiratory tract -only M. haemolytica is beta haemolytic (blood agar) |
|
|
pasteurella (species)
|
-pasteurella multocida* (all: pneumonia & rhinitis)
-manheima haemolytica (all: pneumonia) |
|
|
pasteurella multocida
|
-gram -ve coccobacilli (facultative anaerobes)
-encapsulated (4 types: A,B,C,D) -mucoid colonies -sepitcaemia, pneumonia, rhinitis, fowl cholera |
|
|
manheima haemolytica
|
-cattle: shipping fever (type A1)
-sheep (lambs 2-8wk): pneuomonia (all serotypes) -produce leukotoxin (related to RTX hemolysin of E. coli & A. pleuropneumoniae) -disease following stress (transport, bad weather, predisposing infection -12 serotypes based on capsular antigens |
|
|
pasteurella trehalosi
|
-gram -ve coccobacilli
-facultative anaerobes -acute lamb septicaemia (autum & winter) -long strings of saliva -T capsule ('T type disease') |
|
|
pasteurella (virulence factors)
|
-capsule: poorly immunogenic (b/c similarity to host hyaluronic acid)
-LPS (2 mechanisms): 1. protect from host defense through carbohydrate moiety 2. induce inflammation through lipid A -exotoxins: 1. dermonecrotoxin (type D and some A strains of P. multocida): atrophic rhinitis 2. labile leukotoxin (RTX toxin): M. haemolytica shipping fever & respiratory disease |
|
|
pasteurella (diagnosis)
|
-bipolar organisms (safety pin) in gram or giemsa stain
-P. multocida: on blood agar with distinct odor -culture from nasopharynx no good b/c normal flora |
|
|
pasteurella (species differentiation)
|
M. haemalytica: haemolysis +ve, MacConkey sm. pink colonies, indole -ve
P. trehalosi: haemolysis +ve, MacConkey -ve, indole -ve P. multocida: haemolysis -ve, indole +ve |
|
|
iron regulated protein (IRP) vaccines
|
-highly immunogenic
-protective against M. haemolytica (sheep) -conserved antigenic nature (cross protective between serotypes) -antibodies bind to transferrin binding proteins (block Fe binding) |
|
|
salmonella
|
-gram -ve
-indole -ve -lactose ferment -ve -pathogens of warm blooded animals & commensal sof cold blooded |
|
|
salmonella (species)
|
-salmonella enterica
-salmonella bongori -salmonella tiphimurium -salmonella enteritidis -salmonella gallinarum -salmonella abortuovis -salmonella typhi -salmonella dublin -salmonella choleraesuis |
|
|
salmonella (serotyping)
|
-pathogens of warm blooded animals mostly S. enterica subspecies I
-subdivided by O (LPS) & H (flagella) antigens into serotypes -example serotype: A. typhimurium = S. enterica subsp. I serotype Typhinurium -O antigen ID using sera against LPS (denoted 1,2,3,etc) -similar O types orgainized by serogroup (A,B,C,etc) -capsules only on a few |
|
|
salmonella (disease)
|
-invasive, facultatative intracellular pathogens:
1. enteritis: diahrrea (restricted to gut tissue - don't invade beyond mesenteric LN) 2. septicaemia: abortion, joint infections, pneumonia (spread throughout body incl. liver & spleen) |
|
|
salmonella (host specificity)
|
-non-host specific (non-host adapted): broad host range, eg. S. typhinmurium, S. enteritidis (enteritis in young animals & food poisoning in man)
-host specific (host adapted): narrow range, eg. S. gallinarum, S. abortuovis, S. typhis (systemic infections - young & adult) |
|
|
salmonella (host restricted)
|
-salmonella dublin (cattle): septicaemia, enteritis, abortion, meningitis, joint ill, terminal dry gangrene
-salmonella choleraesuis (pigs): septicaemia, similar to swine fever *both can cause disease in man |
|
|
salmonella (phage typing)
|
-serotype subdivision (eg. S. typhimurium phage type2 or phage type DT104)
-phage type host specific (eg. Tiphimurium PT2 = pigeons, PT12 = pigs, DT104 = cattle & food poisoning) -certain phage types will predominate then subside (reason unknown) |
|
|
salmonella enteritidis PT4
|
-poultry & eggs
-can invade oviduct -interior of egg contaminated -pandemic of salmonella food poisoning in 1980s -chix now vaccinated |
|
|
salmonella vs E. coli (ETEC)
|
-salmonella: invade cells, inflammatory diarrhea
-E. coli: extracellular, non-inflammatory diarrhea |
|
|
salmonella (pathogenesis)
|
-enteritis (non-host adapted serotypes - inflammatory): taken up by macrophages & neutrophils (intracellular)
-septicaemia (host adapted serotypes): mesenteric LN to liver & spleen -invasive (unlike E. coli) |
|
|
pathogenicity islands
|
-large chromosomal regions that encode (often many) virulence genes (toxins, adhesins, secretion systemes, invasins)
-acquire horizontally (from somewhere else) -different G+C content sompare to rest of chromosomal DNA |
|
|
salmonella (pathogenicity islands)
|
-encode for virulence genes
-12 salmonella PIs (strain may not have all 12) -SP1: enteritis -SP2: systemic |
|
|
type III secretion systems
|
-molecular syringes
-look like hypodermic needles -eg. E. coli (very localized effect b/c type III secretion system) |
|
|
salmonella (enteritis)
|
-destruction of epithelium largely due to inflammatory response (massive neutrophil influx)
-diarrhea |
|
|
salmonella (membrane ruffling)
|
-fimbrae attach to villi and inject toxin
-salmonella engulfed leaving ruffled membrane |
|
|
salmonella (survival strategies in macrophages)
|
-acidification of phagosome: prevents phagolysosome fusion
-pathogenicity island 2 responsible |
|
|
yersinia
|
-gram -ve rods
-enterobacteriacae (like salmonella & E. coli) -lactose ferment -ve -motile (except Y. pestis) -bipolar staining (giemsa): looks like safety pin -10 species -serotyping & biotyping to distinguish strains |
|
|
yersinia (species)
|
-yersinia enterocolitica (sheep: subclinical enteritis; ewes: spordic abortion; man: gastroenterocolitis)
-yersinia pseudotuberculosis (enteritis in young, mesenteric lymphadenitis) -yersinia pestis (man: bubonic/pneumonic plague; rodents: sylvatic plague; cats: feline plague) |
|
|
yersinia (epidemiology)
|
Y. psuedotuberculosis & Y. enterocolitica:
-commensal in intestine of wild animals, birds, & domestic animals (all may be resevoirs of infection) -avian species may act as amplifier hosts (transfer mechanically) Y. pesitis: -wild rodents important resevoid -fleas (esp. xenopsylla cheopis: oriental rat flea) transmit to man & others |
|
|
yersinia (pathogenesis of enteric disease)
|
-invade some cells (M cells) & prevent uptake by others (phagocytes)
-gain access to intestinal mucosa via M cells of Peyers paches -adhesion/invasion: invasin binds host integrins -in GI mucosa: prevent phagocytosis, prelicate in mesenteric LN with development of necrotic lesions and neutrophil infiltration |
|
|
yersinia (pathogenesis)
|
-anti-phagocytic proteins secreted (via type III secretion system)
-interferes with neutrophil & macrophage function -yop virulon (plasmid encoded) -extracellular |
|
|
yersinia (pseudotuberculosis infections)
|
-Y. pseudotuberculosis: enteric infections (often subclinical)
-enteric disease common in farmed deer in Australia/New Zealand (sheep, goats, cattle < 1yr) -septicaemia in lab rodents and aviary birds (overcrowding, sudden death, feather ruffling, necrotic foci in liver) -treatment seldom feasible due to acute nature of disease -diahrrea, & weight loss leads to emaciation & death (or sudden death due to septicaemia) |
|
|
yersinia (enterocolitica infections)
|
-primarily a human pathogen
-wild & domestic animals may act as reservoirs -pig is a natural reservoir (serotype 03 biotype 04) |
|
|
yersinia (diagnosis)
|
-histo exams of intestinal lesions
-culture from faeces, pus (from LN), or tissue(enterolitica & psuedotuberculosis) -API 20E (serotyping) -plated on MacConkey |
|
|
yersinia pestis
|
-gram -ve
-causes plague: zoonotic infection in rodents (passed by fleas) -endemic in Africa, Asia, USA (SW & Pac Coast: prairie dogs) |
|
|
yersinia pestis (clinical infection)
|
-can infect dogs & cats (esp. cats)
-zoonotic from fleas -bubonic, septicaemic, pneumonic -cats with pneumonic plague may spread by air (do not euthanize) -human infection from cat scratches and bites and fleas from infected cats |
|
|
yersinia pestis (plague syndromes in man)
|
-bubonic: fever, painful lymphadenopathy (bubo)
-septicaemic: fever, hypotension, +/- bubo -pneumonic: cough, haemoptysis, +/- bubo -meningitis: fever, nuchal rigidity, usually with bubo |
|
|
yersinia pestis (virulence factors)
|
-ymt protein (on plasmid): phospholipase D required for survival in flea
-hms locus: required for transmission to subcutaneous sites (w/o do not lodge en mass in proventriculus) -hpi for iron acquisition (also ye and yp) -fraction 1 (F1) antigen: capsule to prevent opsonization (plasmid encoded) -pla: required to dissementate from subcutaneous site of inoculation to LN or blood stream - anticoagulant (plasmid) |
|
|
yersinia pestis (diagnosis)
|
-pus, blood, LN aspirate to specialist lab
-giemsa stained smears of pus (large number of bipolar rods) -DFA tests (direct fluorescent antibody) |
|
|
yersinia (treatment & control)
|
-cats with suspected plague in isolation
-IV tetracycline (or chloramphenicol) for bubonic plague -flea & rodent control -vaccination (military) -antibiotics (human) -avoid sick/dead animals -insect repellents |
|
|
pseudomonas aeruginosa & burkholderia species
|
-gram -ve rods
-obligate aerobes -oxidise carbohydrates (not fermentative) -oxidase & catalase +ve -motile by 1 or more polar fligella (B. mallei not motile) -grows well on MacConkey agar -P. aeruginosa produces diffusible pigments -P. aeruginosa is an opportunist pathaogen (only in susceptible host) -B. mallei causes glanders -B. pseudomallei causes melioidosis (tropical) |
|
|
pseudomonas aeruginosa (diseases)
|
-cattle: mastitis*, metritis, pneumonia, dermatitis, enteritis (calves)
-sheep: mastitis, fleece-rot*, pneumonia, otitis media -pigs: respiratory infections, otitis -horses: genital tract infections, pneumonia, ulcerative keratitis* -dogs/cats: otitis eterna*, cystitis, pneumonia, ulcerative keratitis -reptiles: necrotic stomatitis (mounth infection) |
|
|
pseudomonas aeruginosa & burkholderia species (habitat)
|
-pseudomonads in water, soil, vegetation (worldwide)
-P. aeruginosa may also be found on skin, mucous membranes & in faeces -B. pseudomallei in soil (esp. SE Asia & Australia) -B. mallei may survive in environment for up to 6wk (resevoir is infected equidae) |
|
|
pseudomonas aeruginosa (infections)
|
-opportunistic infections
-farmed mink particularly susceptible (haemorrhagic anaemia) -bovine mastitis: contaminated water for udder washing or insertion of intramammary antibiotics -fleece rot (sheep): prolonged rainfall (maceration of skin followed by H20 penetration of fleece allows colonization: suppurative dermatitis - pyocyanin pigment discolors wool) |
|
|
pseudomonas aeruginosa & burkholderia species(diagnosis)
|
-analysis of respiratory aspirates, MSU, mastitic milk, ear swabs
-blood agar & MacConkey -green tinged culture (pyocyanin) & distinctive smell -lactose ferment -ve (MacConkey) -oxidase +ve -API 20 NE |
|
|
glanders
|
-burkholderia mallei (gram -ve rod)
-horses: nodules & ulcers in repiratory tract & skin -spread by food or water contaiminated by nasal discharges of infected horses (also inhalation or skin abrasions) -rare (Middel East, India, Pakistan, China, Mongolia) |
|
|
glanders (clinical features)
|
-burkholderia mallei (gram -ve rod)
-acute septicaemia with fever, mucopurulent nasal discharge & respiratory signs -chronic: nasal, pulmonary, & cutaneous forms -ucerative nodules on mucosa of nasal turbinates & nasal septum -purulent nasal discharge & regional lymphadenopathy -cutaneous form (Farcy): lymphangitis with nodules along lymphatic vessels of limbs (ulcers develop & discharge pus) -horse may die or recover & shed organisms (still infectious) -nodules = enlarged lymph nodes |
|
|
berkhoderia (species)
|
-burkholderia mallei (horses: glanders)
-burkholderia pseudomallei (melioidosis) |
|
|
mellioidosis
|
-burkholderia pseudomallei (gram -ve)
-ingestion, inhalation, or skin abrasion (soil or water) -many species (including man): sublclinical (latent) infection may reactivate -abcess formation (acute or chronic, septicaemic, respiratory, disseminated) -opportunistic |
|
|
aeromonas
|
-gram -ve rods
-lactose ferment -ve -oxidase +ve -primarily reptiles & fish -A. hydrophila: beta haemolytic, etneritis, food poisoning (man) -A. salmonicida: brown pigment, furunculosis in salmonids |
|
|
campylobacter
|
-gram -ve ('gull wing' & spiral shaped)
-motile -ferment -ve -oxidase +ve -commensals (intestine) -pathogen in repro & enteric tracts |
|
|
campylobacter (species)
|
ovine abortion:
-campylobacter fetus ss fetus* -campylobacter jejuni* -arcobacter cryoaerophila (not campylobacter) bovine infectious infertility: -campylobacter fetus ss venerealis* (STD) -arcobcter skirrowii (not campylobacter) |
|
|
campylobacter jejuni & campylobacter coli
|
-C. jejuni: normal flora in birds
-C. coli: normal flora in pigs -both: acute diarrhea in very young animals (not older) |
|
|
intestinal campylobacteriosis (dogs)
|
-C. jejuni causes acute diarrhea in puppies (watery or blood)
-typical after acquisition (later owner or child gets it: zoonotic) -healthy animals may shed C. jejuni with no symptoms -colitis: lesions of focal congestions & mucus production |
|
|
campylobacter fetus ss fetus
|
-sporadic abortion in sheep (often late gestation)
-transmitted by contaminated food or water -bacteraemia: spreads to distal sites (including placenta) -ovine abortion in 3rd trimester (placentitis) -sporadic abortion in cattle, goats, pigs & horses |
|
|
campylobacters (sheep abortion)
|
-present in intestine
-invades tissues to uterus -invades foetus (kills) -aborted mummified foetus -campylobacter in foetal liver -campylobacter in discharges -vaccine available -pathogenesis: s-layer on bacteria does not bind c3b (complement) & prevents phagocytosis by neutrophils |
|
|
campylobacter fetus ss venerealis
|
-bovine venerial campylobacteriosis (BVC): sexually transmitted
-ascending infection (cows) from vagina to cervix to uterus (then oviducts: kills eggs) -temporary infertility (rare abortion) -immunity develops via IgA (vaginal mucosa) & IgG (uterus) -organism recovered from glans penis & distal urethera of bull |
|
|
campylobacter fetus ss venerealis (BVC pathogenesis)
|
-persistent in vagina (cow) due to antigenic shifts in the immunodominant antigens of S layer proteins (sapA)
-genomic rearrangement of this locus in weekly isolates -sapA promoter on invertible segment that can flip & allow change in expression from S layer protein gene cassettes |
|
|
campylobacter (enteritis in man)
|
-C. jejuni* & C. coli
-zoonotic: from animals via food (broiler chickens*, raw meat, unpasteurized milk, untreated water, shellfish) -severe abdominal pain, diarrhea (bloody/watery), fever, myalagia (muscle tremor), malaise |
|
|
campylobacters (virulence factors)
|
-cia (campylobacter invasion antigen) protein: secreted by flagella & tanslocate effector proteins into host cell
-glycosylation of flagella, LOS, OMPs to eveade immune response -activation of host inflammatory mediators (IL-8, LTB4, PGE2) -colonize via flagella (in association with mucus on intestinal villi): secrete proteins -pVir plasmid, type IV secretion system, invade cultured cells (tissue invasion) |
|
|
arcobacters (laboratory ID)
|
-selective media (antibiotics to suppress commensals)
-microaerophilic -colonies small (1-2mm) -confirm by smear, gram stain -looks like seagull wings -API |
|
|
arcobacters
|
-arcobacter cryaerophilus: late term abortion in swine, cattle, horses, sheep dogs (mastitic milk, ovine faeces)
-arcobacter butzleri: diarrheal disease in man (animals - potentially zoonotic) -arcobacter skirrowii: diarrheal disease in man, lambs, calves, abortion in swin & cattle -aerotolerant -rare compared to campylobacters (similar morphology) |
|
|
helicobacters
|
-helicobacter pylori (mammals & birds)
-helicobacter hepaticus (mouse) -helicobacter bilis (hepatitis in mice) |
|
|
helicobacter pylori
|
-not a vet pathogen (except cats)
-chronic active gastritis -duodenal & gastric ulceration -risk factor for gastric adenocarcinoma & lymphoma |
|
|
fungi (mycology)
|
-eukaryotes
-uni or multicellular organisms -defined nuclei -cell walls of carbohydrate & chitin (plants) -saprophytic or parasitic -vegetative & sexual reproduction |
|
|
fungi in vet medicine
|
-dermatophytes: grow on hair & skin
-yeasts: grow on mucus surfaces & in body -systemic: hyphae & yeasts -fungal products: beneficial (antibiotics) and harmful (mycotoxins) -fungal spoilage: animal foods (decreased nutritional value, unpalatable: chitin not digestable), forages, animal products (meat & hides) |
|
|
hyphae
|
-long, branching filamentous cell of a fungus
-main mode of vegetative growth (collectively called a mycelium) -form fungal bodies & fruiting bodies (eg. toadstools) -one or more cells surrounded by a tubular cell wall -divided into cells by internal cross-walls called septa |
|
|
zygomycetes
|
-hyphae non-septate
-asexual spores in sporangium -sexual spores, oospores, or zygospores -mucor, rhizopus, absidia, saprolegnia |
|
|
mucor
|
-bread mould & mould on damp food
-hyphae 5-15mu (bigger than most bacteria) -greyish white aerial mycelium -pinhead fruiting bodies (sporangia contain spore) -mycotic abortion -rumen ulcers -systemic mycosis in young or debilitated animals -meat spoilage |
|
|
saprolegnia
|
-aseptate hyphae, branching hyphae
-cylindrical sporangia, open by pore -shed motile zoospores into water -penetrate damaged skin of fish -fuzzy growths on surface -culture on dilute cornmeal agar (16-20deg) |
|
|
yeasts
|
-single cells
-reproduce vegetatively by budding -occasionally form pseudomycelium -sexual reproduction by forming ascospores (resistant) within cell -candida, malassezia, cryptococcus, histoplasma |
|
|
candida
|
-oval cells (gram +ve: look like very large cocci)
-pseudohyphae -germ tubes (side extension) -chlamydospores (tough, resistant) -creamy white 2mm colonies -API system for ID |
|
|
pseudohyphae
|
form in a line like hyphae but actually individual cells that have longated to take advantage of environmental condtions
-candida |
|
|
candida albicans (disease)
|
-cattle
-mycotic abortion -rumenal infections -mastitis -pigs: dermatitis -dogs: chronic enteritis & dermatitis, vaginitis/vulvitis in diabetes (esp. if spayed too early) -birds: crop infections, eneteritis |
|
|
malassezia
|
-very common
-bottle shaped -M. pachyderatis -lipase, urease production -otitis externa -dermatits |
|
|
cryptococcus
|
-C. neoformans: CAT3 pathogen (though only CAT2 in cats - less pathogenic)
-nasal cavity of cats with chronic rhinitis -mucilaginous capsule -big (circular: cell in center with capsule surrounding) |
|
|
dimorphic fungi
|
-histoplasma capsulatum farcinimosum
-epizootic lymphangitis -horses -CAT3 (notifiable) -India, Africa |
|
|
dermatophytes
|
-common
-septate branching hyphae -digest keratin -microconidia (in culture), arthrospores (in hairs), macroconidia (in culture) -Epidermophyton, Microsporum and Trichophyton -ID by surface appearance (large fuzzy white colonies) and color of underside (yellow) -vegetative spores |
|
|
mycology
|
the study of fungi, their genetic and biochemical properties, their taxonomy, and their use to humans as a source for tinder, medicinals (e.g., penicillin), food (e.g., beer, wine, cheese, edible mushrooms) and entheogens, as well as their dangers, such as poisoning or infection
|
|
|
microsporum
|
-dermatophyte
-ringworm (man & animals) -anthropophilic (human-seeking), zoophilic (animal-seeking), & geophilic (earth dwelling) -microconidia (vegetative spores) en thyrse (arranged singly along both sides of hypha) |
|
|
conidium
|
-an asexually produced spore of some types of fungi
-microconidia & macroconidia |
|
|
microsporum canis
|
-ringworm in cats & dogs transmissible to man
-grows on hair with arthrospores ectothrix (outside hair shaft) -microconidia (vegetative spores): relatively common -macroconidia: elliptical with up to 14 divisions (rare on isolation) -fluoresces -colonies smooth surface (white fuzzy), yellow underside |
|
|
microsporum (species)
|
-microsporum canis (ringworm in cat/dog)
-microsporum gypseum (many macroconidia, dog, geophilic) -microsporum equinum (horses) -microsporum nanum (pigs: not UK) |
|
|
trichophyton
|
-dermatophyte
-zoophilic -ringworm in man & animal -club shaped macroconidia -microconidia en thyrse (along side of hyphae) & en grappe (grape like cluster) -spiral hyphae -no fluorescence (unlike M. canis) |
|
|
trichophyton (species)
|
trichophyton verrucosum:
-ringworm in cattle (transmissible to man) -abundant chlamydospores (resistant up to 5yr: get on fence post) -large spore ectothrix hair (around outside) -slow growing colonies deep in agar T. mentagrophytes (dog, horse) T. equinum (horse) T. gallinae (fowl) |
|
|
ringworm
|
-microsporum (M. canis: cats/dogs, eg.)
-trichophyton (T. verrucosum: cattle, eg.) -both dermatophytes |
|
|
aspergillus
|
-on meat, bread, hay
-septate branching hyphae -sporing heads or conidia in oxygen -conidiophore & sterigmae (support conidiae) -may have sexual stages (not A. fumigatus) -species: A. fumigatus, aspergillus flavus |
|
|
aspergillus fumigatus
|
-on food & fodder
-spores infect young non-immune or immunosuppressed animals -star shaped colonies -greenish blue with sporing heads -do not sniff! |
|
|
mycotoxins
|
-aspergillus flavus (mouldy peanuts, eg.): produces aflatoxin (carcinogenic)
-claviceps purpurea (ergot on rye grass): produces alkaloids (activity on sm. muscle of arteries - abortion in cows) -fusarium culmorum: produces zearelenone/f2 toxin (hormanal like E2: infertility in pigs) -deoxyvalenol: vomitoxin -fusarium moniliforme: fumonisin (on maize) - pigs -penicillium rubrum: rubratoxin (in feed - nephrotoxic) -penicillium viridicatum: ochratoxin A -prinicillium chartarum: sporeodesmin (facial eczema) |
|
|
trichophyton (species)
|
trichophyton verrucosum:
-ringworm in cattle (transmissible to man) -abundant chlamydospores (resistant up to 5yr: get on fence post) -large spore ectothrix hair (around outside) -slow growing colonies deep in agar T. mentagrophytes (dog, horse) T. equinum (horse) T. gallinae (fowl) |
|
|
ringworm
|
-microsporum (M. canis: cats/dogs, eg.)
-trichophyton (T. verrucosum: cattle, eg.) -both dermatophytes |
|
|
aspergillus
|
-on meat, bread, hay
-septate branching hyphae -sporing heads or conidia in oxygen -conidiophore & sterigmae (support conidiae) -may have sexual stages (not A. fumigatus) -species: A. fumigatus, aspergillus flavus |
|
|
aspergillus fumigatus
|
-on food & fodder
-spores infect young non-immune or immunosuppressed animals -star shaped colonies -greenish blue with sporing heads -do not sniff! |
|
|
mycotoxins
|
-aspergillus flavus (mouldy peanuts, eg.): produces aflatoxin (carcinogenic)
-claviceps purpurea (ergot on rye grass): produces alkaloids (activity on sm. muscle of arteries - abortion in cows) -fusarium culmorum: produces zearelenone/f2 toxin (hormanal like E2: infertility in pigs) -deoxyvalenol: vomitoxin -fusarium moniliforme: fumonisin (on maize) - pigs -penicillium rubrum: rubratoxin (in feed - nephrotoxic) -penicillium viridicatum: ochratoxin A -prinicillium chartarum: sporeodesmin (facial eczema) |
|
|
brucella
|
-small gram -ve coccobacilli
-motile -ve, sporing -ve, fermentative -ve -oxidase +ve -intracellular (phagocyte) -koster's stain (modified -ZN) -complex media required (some need CO2) |
|
|
brucella (species)
|
-B. abortus (cattle: contaigious bovine abortion, orchitis)
-B. melitensis (sheep/goats: orchitis & abortion) -B ovis (sheep: abortion & epididymitis) -B. canis (dogs: abortion, epididymitis, arthritis) -B. suis (pigs: abortion, infertility, orchitis) |
|
|
brucellosis (pathogenesis)
|
-penetrates mucosa (type IV secretion system): resists serum killing
-phagocytosis/invasion to regional LN (inflammation) -persistence (bacteraemia) & dissemination -to testis, udder (excretion), uterus (placentitis & abortion) |
|
|
bordatella
|
-small gram -ve coccobacilli
-strictly aerobic -oxidase +ve -non-sporing, most motile -not fermentative -respiratory tract pathogens |
|
|
bordatella (species)
|
bordatella bronchiseptica (dogs: kennel cough; cats: resp infections; pigs: progressive atrophic rhinitis)
-bordatella parapertussis (sheep: resp infections; man: whooping cough) -bordatella avium (turkeys: respiratory infection) -bordatella pertussis (man: whooping cough) |
|
|
bordatella bronchiseptica(pathogenesis)
|
1. attachment to ciliated cells (tight adhesion)
2. production of toxins (paralyse cilia) 3. loss of cilia: interferes with innate & specific immune response (accumulation of mucus) |
|
|
bordatella (virulence factors)
|
adhesins:
-fimbrae -filamentous haemagglutinin (FHA) -pertactin toxins: -adenylate cyclase toxin (haemolysin) -tracheal cytotoxin -dermonecrotic toxin |
|
|
bordatella (regulation of virulence)
|
-temperature dependent
-37 degrees: virulence genes expressed -25 degrees: virulence genes not expressed |
|
|
bordatella bronchiseptica (atrophic rhinitis: pathogenesis)
|
1. attachment to ciliated cells (tight adhesion)
2. production of toxins (paralyse cilia) 3. loss of cilia: interferes with innate & specific immune response (accumulation of mucus) 4. colonization with P. multocida (type A or D) |
|
|
moraxella bovis
|
-gram -ve short plump rods (often in pairs)
-strict aerobes, non-sporing, "twitching motility" -oxidase +ve -not fermentative -infectious bovine keratoconjuctivitis (new forest eye, pink eye) -virulence factors: fimbrae (pilli) |
