Streptococcus Flashcards
gram, shape, arrangement
-gram positive
-cocci
-chains
respiration, motility, spore, catalse
-facultative anaerobe
-non motile
-non spore forming
-catalase negative
growth requirements
-fastidious growth – requires nutritionally rich media
-cannot grow in high salt
blood agar
-B – most pathogenic strep, complete hemolysis
-a – partial and incomplete hemolysis, green color, upper respiratory tract strep
-y – fecal strep, no hemolysis
whaat selective media for isolation adn identification of strep
edward media
serogrouping method for strep
lancefield serogrouping
clincially important serogroups
A, B, C, D, E, G
what hemolysis are most equine and canine isolates
beta hemolytic
beta hemolytic strep
group A – S pyogenes (tonsilitis)
group B – S agalactiae
group C – S equi, equismullis, zooepidemicus, dysgalactiae
group E – S procinus (swine)
group G – S canis
alpha hemolytic Strep
optochin sensitive – S pneumonaie
optochin resistant – S suis and viridans strept
gamma hemolytic strep
group D – enterococcus, Strept bovis (S gallolyticus)
what casues meningitis and pneumonia in children
S pneumoniae
habitat
skin, upper respiratory, tonsils, digestive tract, lower urogenital tract, udder/teat duct
transmission
-opportunisitc pathogen
-bacteria enter cuts, abrasions
-weakened immune system
-primary disease
-spread by direct contact, aerosol, fomites, ingestion (sometimes)
structural compounds – lipoteichoic acid
-adhesion, cytotoxic for most host cells
structural compounds – capsule (slime layer)
-prevents chemotaxis
-adhesion
-hide by deposition of host sialic acid residues
-prevent bacterial recognition by phagocytes
-prevent complement assisted opsonization
structural compounds – M protein
-adhesion
-inhibition of phagocytic ingestion
-binds to Fc region of IgG
-prevents opsonization
structural compounds – protein G
-compete with complement
-bind with Fc region of IgG
-prevent opsonization
enzymes – nuclease (A, B, C, D)
-liquifaction of pus (uses pus to grow)
-DNAse activity (A, C) and RNAse activity (B, D) to destroy host cells and defenses
enzymes – streptokinases
-conversion of plasminogen to plasmin, leads to digestion of fibrin
-lyse blood clots to escape and spread out
enzymes – C5a peptidases
-destroy C’ chemotactic signals (C5a)
-blocks chemotaxis
toxins – hemolysin (a, B, y)
-destroys RBCs, neutrophils, macrophages, platelets
toxins – exotoxins (streptolysin O and S)
-hemolytic on blood agar
-kills phagocytes
-inhibit phagocyte attraction (inhibit chemotaxis)
toxins – pyrogenic exotoxins (fever causing) (A, B, C)
-fever, strawberry rash
-cardiac and liver necrosis
-T cell division
-superantigen
-increase endothelium and blood brain barrier permeability
4 directions strep advances from
-cutaneous – pus, abscess
-throat
-mammary
-urogenital
emerging zoonotic strep from animals to humans
S suis (pig)
S gallolyticus (chickens)
strep pyogenes in humans
-scarlet fever – pharyngitis
-strep throat infection
-lymph node and tonsil infection
-strawberry rash
-necrotizing skin fascilitis
-flesh eating by pyrogenic exotoxins
strep in horses
-throat infection = pharyngitis
-pus accumulation in throat
-generalized infection
-reproductive tract infection
-abortion, vaginitis, postpartum endometritis
-strangles
-S. dysgalatiae subspecies equisimilis
-S. equi subspecies zooepidemicus
-Streptococcus equi subspecies equi
strep in pigs
-throat infection, porcine strangles, pharnygitis
-pus in throat, jowl abscess (feeder boils)
-contagious cervical lymphadenitis
-generalized infection
-deafness, blindness, meningitis, speticemia
-pupura hemorrhagica on leg
-gangrene down to foot
-S. porcinus – rare now
-S. suis – most common problem in pig industry
-S. equi subspecies zooepidemicus (occasionally)
strep in pets
-throat infection – pet strangles
-generalized infection – septicemia, pneumoina, memnigitis
-eye and ear – blindness, otitis
-reproductive tract
-S canis – major problem
-S. equi subspecies zooepidemicus – emerging problem
-S. agalactiae, S. pneumoniae, S. suis, S. pyogenes – occasional problem
strep in ruminants
-S. uberis – mastitis
-S. dysgalatiae – acute contagious/environmental mastitis, polyarthritis
-S. agalatiae – chronic contagious mastitis
-Occasionally S. equi subsp. Zooepidemicus – metritis (abortion), mastitis
alpha hemolytic strep – greening (viridians)
-S mitis, S mutans, S salivarius, S snguis, S miller
-normal flora of oral cavity, intesinte, urethra
-endogenous infection
control
-hygiene, wellbeing, reducing stress, control of primary diseases
-vaccine for S pneumoniae in humans
which strep only causes bovine mastitis
S uberis
