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25 Cards in this Set
- Front
- Back
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Morphology of Streptococcus
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Gram POS cocci (or short rods), typically found in LONG CHAINS. May be in short chains which become harder to ID (particularly Strep. equi) so look out.
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Are there more Strep spp or Staph spp?
Where are Strep found? What is the O2 req of Strep? |
Strep spp
Mucous Membranes and Skin of most vertebrates, reptiles, and fish. Facultative Anaerobes |
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Are Strep catalase positive or negative?
What about the Enterococcus catalase test? |
Step = Catalase NEG
Staphy = Catalase POS Enterococcus may be pseudocatalase. |
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Hemolysis... tell me about it
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Have NO diagnostic significance whatsoever for Staphylococcus.
Is a diagnostic tool for Streptococcus! |
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Alpha Strep
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do not lyse erythrocytes, but produce a green discoloration around the colony as hemoglobin changes to methemoglobin.
Most Commensal Strep are Alpha (referred to as viridan strep) [viridan = greening] |
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Beta Strep
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lyse erythrocytes - produce clearing zones.
Most Beta-Strep are pathogenic (and the hemolysis can be part of the PATHOGENESIS too, unlike in Staph) |
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Name 5 species of Beta Hemolytic Strep
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S. pyogenes (human)
S. canis (dogs) S. equi (horses) S. zooepidemicus (variant of equi) S. agalactiae (human) |
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Gamma Strep
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No lysis, most are Non-Pathogenic or Opportunists
Enterococcus is one example. |
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How are Beta-Strep classified?
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Serologically sorted into (Rebecca) LANCEFIELD groups.
20 Groups (A-H, K-V) Animal Pathogens A,B,C,D,E,G,L,V |
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What bacteria have no Lancefield group?
Have no serologic subdivision? |
S. uberis, S. parauberis, S. pneumoniae
S. equi |
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Big difference bw Strep and Staph pathogenesis?
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Strep are Facultative anaerobes --- usually cause their major infections much deeper than Staph (which harshly infects the skin).
Strep like to get away from the O2 and can be fairly fastidious as well |
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Virulence Factors for Strep are mostly like Staph
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So review the Staph cards!
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Difference bw Strep / Staph Capsules?
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Staph capsule = polysaccharide, very immunogenic... bring the cells in and KILL THEM
Strep capsule = hyaluronic acid, poorly immunogenic... HIDE! |
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What is PSA?
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Pneumococcal Surface Antigen
Lipoprotein found on S. pneumoniae, S. equi - equi, and S. equi - zooepidemicus Responsible for binding to cells that line the airways |
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Most strep of veterinary interest are commensals of ________ and ______.
How are strep transmitted? |
Upper Respiratory, and GI tracts
Inhalation, Ingestion, sexually, congenitally, or via Fomites |
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What does Strep pyogenes cause?
(Group A) |
(Human) Strep throat, pyoderma, puerperal fever, scarlet fever, rheumatic fever.... Just take some Penicillin.
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What does Strep agalactiae cause?
(Group B) |
neonatal sepsis (human)
mastitis (cows) Treat with Penicillin GB-Mastitis is on the UP because of the desire for "organic" production. |
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What test is used to ID Group B Strep?
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CAMP Test
Run Staph aureus down center of a blood agar plate. Run test subject perpendicular up to this streak. If an "arrow" forms, the bacteria augmented the hemolytic activity of Staph and it is POSITIVE for CAMP and is a GROUP B STREP |
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Whats up with Group C Strep?
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They infect horses.
S. dysgalactiae - dysgalactiae = mastitis S. dysgalactiae - equisimilis = suppurative conditions S equi - equi = strangles S equi - zooepidemicus = pneumonia |
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Whats up with Group D Strep?
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They are mostly really Enterococcus, not strep.
S. bovis and S. equinus are actually a couple STREP that are Group D Strep. ...however they are actually the same organism... so all in all, Group D is for DUMB! |
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What is the Group G Strep?
(of vet significance) |
S. canis
Infects carnivores (mostly dogs) -Feline lymphadenitis -Secondary pneumonia in dogs/cats -Septicemia in puppies -Assoc with Toxic Shock and Necrotizing Fasciitis in Dogs |
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What about Group E (P, U, and V)??
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S. porcinus
Cervical lymphadenitis in pigs |
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And Group R, S, RS, T (and D)??
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S. suis
encephalitis, meningitis, arthritis, abortion, and endocarditis in pigs septicemia in pigs and occasionally birds |
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Ungroupable strains?
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S. uberis - bovine mastitis
S. pnuemoniae - human pneumonia |
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What organism will be the bane of our existence?
Why? |
Enterococcus
They are resistant to EVERYTHING! Occasionally susceptible to tetracycline, amoxicillin... they are susceptible to vancomycin (used on human MRSA as a last result) Vancomycin not used in vet med (because we are not allowed to, they are reserved for human med) |
