Week 4 - gram positives Flashcards
Adhesins (staph)
tissue colonization
Hemolysins (staph)
tissue destruction (cytolytic)
Enterotoxins (staph)
tissue destruction, heat stable toxin
TSST (staph)
tissue destruction, superantigen leading to excessive cytokine release
Protein A (staph)
immune evasion, binds Fc portion of IgG, inhibits opsonization
leukocidin (staph)
immune evasion - leukocidal
Coagulase (staph)
immune evasion - hide bacteria from PMNs
Bovine staphylococcal mastitis genus
S. aureus.
Bovine staphylococcal mastitis classifications
Epi = environment or contagious Clinical = subclinical or clinical
Bovine staphylococcal mastitis source of infection + transmission
infected mammary gland of another cow in the herd
Transmission: milking with contaminated hands, teat cup liners and udder cloths
Bovine staphylococcal mastitis predisposition
impaired phagocyte function in the host
Peracute gangrenous mastitis
due to local thrombosis and edema caused by S. aureus. tissue necrosis, discoloured udders, swollen quarters, fever, anorexia
Bovine staphylococcal mastitis treatment and prevention
good hygiene while milking, therapies given during the dry period, check for subclinical infections, segregate infected cows, cull chronic cows, prevent induction of positive cows into the herd
Botryomycosis
caused by S. aureus
chronic, granulomatous disorder with formation of micro-abscesses. Post-castration complication in horses.
Tx: long-term antibiotics, surgical removal of affected tissue
Prevention: hygiene, wound care
Bumblefoot
local, chronic pododermatitis and tenosynovitis in birds.
prevention: good husbandry
S. pseudointermedius
causes local skin diseases in dogs and cats (pyoderma, otitis), most common opportunistic infection in dogs/cats.
Infections will be caused by an overgrowth of resident bacteria
Treatment and prevention of pyoderma
ID underlying issues! cleansing shampoo + antimicrobial shampoo, narrow-spectrum antiBs, grooming and clipping of hair coat
Greasy pig disease
highly contagious exudative epidermitis in suckling or weaning pigs. excessive sebum production, anorexia, fever. morbidity and mortality high.
S. hyicus may be found in vagina of sows and preputial diverticulum of boars. Enters through bite wounds
Greasy pig disease treatment and prevention
systemic antiBs + topical treatment, isolate infected pigs, clean + disinfect contaminated buildings, clip needle teeth in newborns, soft bedding
Toxic shock syndrome
TSS is caused by superantigens entering the bloodstream. causes fever, headache, vomiting, diarrhea, conjunctival reddening, hypotension, skin rashes, kidney failure
Staph diagnosis
specimens: exudate, pus, mastitic milk, skin scrape, urine, affected tissues
microscopy + gram stain, isolation on blood agar/MacConkey agar, PCR
Strepto types of hemolysis
beta = clear, complete hemolysis alpha = green, partial hemolysis gamma = no hemolysis
Streptokinase + hyaluronidase (strepto)
invasion
protein F strepto
adhesion
M protein, hyaluronan, streptolysins
evasion
streptococcal pyrogenic exotoxins, lipoteichoic acid
toxins
Strangles/equine distemper
S. equi subsp. equi
highly contagious, upper resp disease. abscessation + swelling of LNs can obstruct airway. Enzootic, but not commensal.
High morbidity, low mortality
All ages susceptible, more common in foals
Strangles transmission
via purulent exudates from upper resp/discharging abscesses from diseased animal or carrier (direct or indirect contact)
Strangles CS
high fever, depression, anorexia followed by purulent oculonasal discharge. submandibular and retropharyngeal LNs affected and eventually rupture
Guttural pouch empyema
complication of strangles. due to accumulation of purulent exudate in guttural pouch. stiff head carriage, painful swelling in parotid region, difficulty breathing
Bastard strangles
strangles complication. disseminated infection with abscessation in many organs
Purpura hemorrhagica
immune-complex mediated vasculitis (complexes deposit in vessels)
Strangles diagnosis
CS, culture from abscess/nasal swab/lavage fluid, serology (anti-M protein), PCR for M protein
Strangles Tx
symptomatic: relieve pain, drain mature abscesses
anti-Bs only effective if given soon after exposure/before abscesses form
Vaccine - not 100% effective. inactive vaccine for pregnant mares and foals for high anti-M levels. Live intranasal vaccine for mucosal immunity + serum antibodies
Strangles prevention
stop movement of animals upon suspected infection, quarantine!!!! hygiene, disinfection. Notifiable disease in many states. 3 negative cultures at weekly intervals allows release from quarantine
Streptococcus suis
causes significant losses. Associated with meningitis, arthritis, septicemia, bronchopneumonia. particularly in young pigs. Carrier rate is almost 100% (in tonsils), but low disease rates.
Streptococcus suis treatment + prevention
penicillin or ampicillin. make sure to serotype as many different ones exist!
Prophylaxis: long-acting penicillin to sows pre-farrowing and to pigs during first 2 weeks of life. Good husbandry + hygiene
eradication not feasible!
Streptococcus suis zoonosis
underreported and underdiagnosed. risk: employees in swine industry and consumption of raw meat
Bovine streptococcal mastitis (contagious)
S. agalactiae colonizing milk ducts - persistent infection w/ intermittent bouts of acute mastitis
Bovine streptococcal mastitis (environmental)
S. dysgalactiae - colonizes buccal cavity and genitals, skin of mammary gland. Acute mastitis
S. uberis - skin, tonsils, vagina - subclinical mastitis
Bovine streptococcal mastitis Tx + prevention
prepare cows properly for milking, have a good milking system, well-balanced nutrition and hygiene, screen cows before introducing to a herd, monitor somatic cell counts in milk
