gram pos -> strep and enterococcus

Question 1

strep characteristics

Answer 1

• cocci in chains
• grma pos
• fastidious
• No growth in NaCl
• Need serum
• Commensals/parasites of mammals
• Some highly pathogenic
• Facultative anaerobes
• Some strict anaerobes
• Catalase negative

Question 2

compare and contrast staph and strep

Answer 2

staph:
- grows on basal media, large colonie, gram pos cocci in clusters, catalase pos

strep:
- requires enriched media, small pinpoint colonies, gram pos cocci in chains, catalse neg
- more pathogenic, not as resistant to enviro but more resistant to pahgocytosis

Question 3

what is lacefield’s goruping of strep classified by

Answer 3

• antigenicity of cell wall polysaccharides

Question 4

what are the viruelnce factors of A strep

Answer 4

• capsule hyaluronan = not recognised by host -> evade host
• produce toxins -> lipoteichoic acid
• M protein = evasion

Question 5

what do antibodies react to in strep

Answer 5

• M and M-like proteins

Question 6

what is S pyogenes

Answer 6

• group A human disease
• Strep throat, scarlet fever, skin infections, rheumatic fever
• Necrotizing fasciitis (Flesh-eating bacteria)
• Toxic shock like syndrome

Question 7

what are Enterococcus faecalis/facium

Answer 7

• group D
• opportunistic infections of animals

Question 8

what are S. pneumoniae

Answer 8

• no group
• diplococcus
• pneumonia in humans

Question 9

what is strangles

Answer 9

• Most important infectious disease of young horses and donkeys
• Strep equi sub equi
• Highly contagious upper respiratory tract infection
• non-commensal -> comes from animals incubating/notshowing signs yet or recovering carrier animals
• Highly infectious to non-immune stock
• Nasal secretions from pasture and water troughs are sources of infection
• High density of horses major risk factor
• Natural immunity short lived
• High risk of acquiring infection when assembling horses at sales, shows
  and race courses

Question 10

what are the possible pathways of strangles

Answer 10

abscessation in local lymph nodes (head) -> can spread to lungs/brain and cause purpura hemorrhagica (blood veessel inflammed due to response of immune system)
OR
lymph node ruptures -> thick cremay yellow puss if external, gutteral puch empyema if internal, leading to carrier shedding for months

Question 11

what is strep suis

Answer 11

• Most common cause of meningitis in
  weaned pigs and now in growers
• speticaemia, pneumonia
• 33 serotypes -> capsular type 2 = high virulence
• Cps7, 9 and 14 are important
• Most pigs carry in tonsils
• Virulent strains: Isolation from brain, heart and joints
• Isolation from Lung indicates pneumonia
  can be associated with other infections
• Sensitive to penicillin

Question 12

why do low antimicrobial use farms have more problems with S. suis

Answer 12

• penicillin not used often so more infections
• the opportunistic bacteria (commesnal) are not suppressed and multiply moore freely
• more secondary infections can occur = opportunity

Question 13

why is S. suis a concern

Answer 13

• ZOONOTIC in the type 2 form -> severe infection in humans
• rare outside asia
• 3 confirmed cases in AUS

Question 14

what is subclinical vs clinical mastitis

Answer 14

1. Subclinical mastitis: No signs of infection. Major significance to
   dairy industry
2. Clinical mastitis: is an inflammatory response to infection causing
   visibly abnormal milk (eg, color , fibrin clots). As the extent of the
   inflammation increases, changes in the udder (swelling, heat, pain,
   redness) may also be apparent.

Question 15

what are the 3 types of clinical mastitis

Answer 15

-acute : suppurative
-chronic: granulomatous
-gangrenous -> S.aureus

Question 16

what mastitis can strep Agalacticae cause

Answer 16

• contagious mastitis only
• most contagious
• Obligate parasite of the udder
• Can be eliminated with mastitis control programme -> easier to treat
• Infection does not result in gland destruction
• Once the most important cause of mastitis (with S.aureus)
• Now virtually eradicated from most milk producing countries

Question 17

what mastitis can S. dysgalacticae cause?

Answer 17

• contagious and environmental -> sporadic acute infections

Question 18

whhat mastitis does S. uberis cause

Answer 18

• environmental only
• Sporadic infections resulting from teat trauma or contaminated
  environment (major pathogen in Australia)
• MOST PREVALENT IN AUS

Question 19

what mastitis does S.aureus cause

Answer 19

• paracute gangrenous mastitis, acute, chronic (subclinical)
• very virulent
• toxins

Question 20

what mastitis does S.epidermis cause

Answer 20

• chronic mastitis
• usually found on skin -> often contaminant from bas sampling

Question 21

what else can cause mastitis except strep

Answer 21

• Environmental mastitis: mud,
  manure, bedding material
  Escherichia coli, Pseudomonas
  aeruginosa, Klebsiella pneumoniae
• Summer mastitis: infection of
  predominantly dry cows, flies can
  transmit bacteria. Trueperella
  pyogenes
• Sporadic mastitis:
  Mycoplasma, Nocardia

Question 22

what is enterococcus spp

Answer 22

• Major species are E. faecalis/faecium (Group D strep)
• part of gut flora
• Causes opportunistic infections:
• Wound infections in all species
• Mastitis in cattle
• UTI and ear infection in dogs
• Intrinsically resistant to range of Antimicrobials
• Vancomycin resistance major problem in humans
• vanA and vanB genes -> cause resitance
• Vancomycin resistance linked to avoparcin use in
  animals

Question 23

what is Vancomycin resistant entero?

Answer 23

• Serious nosocomial infection
• Reservoir of VRE in animals in countries using avoparcin as growth promoters
• Difficult to assess direct link

Question 24

how is strep controlled

Answer 24

• Treatment: Antimicrobials (sensitive to penicillin however resistance is on the rise)
• Vaccines: Vaccination made difficult because of the numerous antigenic types.
• Autogenous vaccine may be effective

Question 25

what is an autongenous vaccine

Answer 25

An autogenous vaccine is a vaccine prepared from a microorganism(s) isolated from a sick or dead animal, which the attending veterinarian believes is the causative agent(s) of the disease affecting the flock or herd” APVMA - prepared in response to immediate need