Gram Pos: Streptococcus & Enterococcus

Question 1

Describe the key bacterial characteristics of Strepococcus.

Answer 1

-gram pos cocci in chains
-facultative anaerobes
-non motile, non spore forming
-catalase (-)
-fastidious
-commensal on mucus membrane
-human & animals (host specific)
-opportunistic (secondary)
-dont survive well in environment
-acute suppurative infection (abscess)
-local & systemic infection
>ex: septicimia, LN, mastitis, pneumonia

Question 2

Describe the different types of testing.

Answer 2

1. Hemolytic
   -B hemolytic (complete) [pyogenic spp]
   -a hemolytic (partial) [s. Suis, s. Dysgalactiae]
   -gamma hemolytic (no hemolysis) [enterococcus spp]
2. biochemical test: lancefield classification
   >ag-ab test based on cell wall polysaccharide antigen (C substance) -> group A-H
   >ring precipitation & latex agglutination test

Question 3

Describe the virulence factors & pathogenesis.

Answer 3

Question 4

Describe the species of vet imp.

Answer 4

Question 5

Describe streptococcus equi subspecies equi.

Answer 5

‘Strangles, equine distemper’
-highly contagious
-URT
-abscess of submandibular & retropharyngeal LN = airway obstruction -> death
-enzootic, NOT a commensal
-transmission via purulent exudates
-can be carriers
-morbidity 100%, mortality 5%
-all ages but mostly yearlings & weaned
-incubation = 3-6d (disease is 5-10d)
-CS: fever, depression, anorexia, discharge

Question 6

Describe the complications of strangles.

Answer 6

1. Guttural pouch empyema (most common)
   -secondary to URT inf
   -purulent exudate in pouch
   -stiff head, swelling, diff breathing
2. Bastard strangles (rare)
   -systemic, disseminated inf w abscess in organs
3. Purpura haemorrhagica
   -immune complex mediated vasculitis
4. Carriers

Question 7

Describe the diagnosis & treatment for strangles.

Answer 7

-most recover after abscess mature & rupture = strong immunity
-diagnosis:
>CS
>culture
>serology = ELISA for anti M protein Ab
>PCR = target M protein
-treatment:
>symptomatic carrier = relieve pain & drain mature abscess
>antibiotics soon after exposure & before abscess formation (rec in bastard)

Question 8

Describe the prevention of strangles.

Answer 8

1. Vaccine not 100%
   -inactive vaccine w M protein for preg mare & foal = high level of anti M protein opsonizing Ab
   -intranasal vaccine to stim mucosal immunity & serum
2. Prevention
   -isolate
   -notify
   -3 neg cultures weekly -> release from quarantine

Question 9

Describe the phases of strangles.

Answer 9

1. Incubatory
   -nasal shed 4-7d after exposure w or w/o discharge
2. Clinical
   -shed from sites
3. Convalescent
   -nasal shed up to 6wks after recovery
4. Long term chronic shedding

Question 10

Describe streptococcus suis.

Answer 10

-meningitis, arthritis, septicemia, bronchopneumonia
-‘nursery disease’ = affect pigs 2-5w after weaning
-sometimes endocarditis, neonatal death, abortion
-100% carriers in tonsillar tissue, disease 5%, no treatment mortality is 20%
-serotyping
-predisposing factors: ventilation, temp, bacteria, low immunity, overcrowding, stress
-zoonotic = meningitis in humans

Question 11

Describe the T & P for streptococcus suis.

Answer 11

1. Treatment
   -pen or amp
2. Prevention
   -LA pen inj to sow 1w prior to farrowing
   -LA pen inj to piglets during first 2w of life
   -improve husbandry & hygiene

Question 12

Describe streptococcus agalactiae, s. Dysgalactiae, s. Uberis.

Answer 12

‘bovine streptococcal mastitis’
1. Contagious mastitis
-s. Agalactiae = colonize milk duct (obligate) -> chronic mastitis
2. Environmental mastitis
-s. Dysgalactiae = colonize buccal cavity & genitalia -> acute mastitis (commensal of skin of mammary gland)
-s. Uberis = colonize skin, tonsil, vag mucosa -> subclinical (seen in straw bedding)
more subclinical than clinical

Question 13

Describe bovine streptococcal mastitis T & P.

Answer 13

-pre & post milk teat dipping
-sep paper towels
-reduce teat injury
-segregate chronic mastitis (cull or milk last)
-dry cow treat all
-nutrition & hygiene
-pre screening
-monitor somatic cell count in milk

Question 14

Describe the etiopathology of cattle mastitis.

Answer 14

1. Exposure to microorganisms
2. Host defense mech
3. Environmental conditions

Question 15

Describe streptococcus equi subspecies zooepidemicus.

Answer 15

‘Pyogenic streptococci infections’
-opportunistic causing purulent inf in broad range of animals
-mucus membrane
-URT inf, pneumonia, mastitis, septicemia
-emerging zoonotic pathogen -> necrotizing myositis & meningitis in humans

Question 16

Describe streptococcus canis.

Answer 16

‘Pyogenic streptococci infections’
-toxic shock syndrome
-necrotizing faciitis in dogs & cats
-commensal on skin & mucus membrane
-inf from vag or umbilical v -> peritoneal cavity -> liver -> bacteremia
-septicemia & embolic lesions in heart & lung
toxin & superantigens = lethal

Question 17

Describe streptococcus pyogenes.

Answer 17

‘Pyogenic streptococci infections’
-mild superficial skin disease to life threatening systemic disease
-toxic shock
-flesh eating bacteria = necrotizing faciitis
-non pyogenic = fever

Question 18

Describe the key bacterial characteristics of Enterococcus.

Answer 18

-gram pos ovoid in pairs or short chain
-facultative anaerobes
-some strains motile
-non spore forming
-catalase (-)
-commensal of GIT of human & animal
-opportunists

Question 19

Describe enterococcus faecalis, E. Faecium.

Answer 19

‘Opportunistic infections’
-wound inf
-mastitis in cattle
-UTI & ear inf in dogs
-nosocomial inf
-antimicrobial resistance: VRE vancomycin