Gram + cocci Strep Flashcards
An Elisa Test was used to screeen two cattle herds for the presence of Johne’s Disease. Heard A has a prevalence of 80% and Herd B had a prevalence of 15%. The positive predictive value of this test is much higher in which Herd?
Herd A
Should you ship a sample to a lab in a syringe w/ a needle attached?
NO never dont do it
What would one expect to see in microscopic examination of Streptococcal species?
Gram + cocci in pairs or chains
What type of metabolism do Strep species exhibit?
Facultative Anaerobe (aerobe and anaerobe)
What is a major diagnostic test to differentiate between staph and strep species?
Catalase test
What is the result of the catalase test with Strep species?
Negative- Staph is positive
Where is strep commonly found?
commensal of oral cavity nasopharynx, skin, GI and Genital tracts
A disease can be diagnosed by identifying the infectious agent and the host immune response to that agent? T/F?
True
What is another way to classify Strep species?
Hemolytic classification alpha, beta, gamma
Humoral immune tests are measured by screening for what?
antibodies
the ability of a test to accurately identify an infected animal as positive is known as?
sensitivity
Lower sensitivity in tests can result in?
False positives
the ability of a test to accurately identify a non infected animal as negative is known as?
Specificity
Lower specificity in tests can result in?
false negatives
What is enterococcus resistant of? Oxygen usage?
6.5% NaCl, Bile salts. Facultative anaerobe
what is Peptostreptococcus’ oxygen requirement?
Obligate anaerobe.
What is significant about Abiotrophia?
it is nutritionally fastidious- needs to have staph to grow in lab.
Are beta hamolytic streptococci pyogenic?
Generally.
do some strains of Strep have capsules?
yes
Non pyogenic strains of Streptococcus are usually categorized how when concerning hemolytic properties?
Generally non hemolytic or alpha hemolytic
What is common streptococcal diseases
acute suppurative- local to systemic immunologic post-streptococcal diseases (mostly Human) Subacute (vegetative) endocarditis Chronic Mastitis STSS streptococcal toxi shock syndrome Necrotizing Fasciitis and Myositis (NFM)
What test is unique to Streptococcus species?
Lancefield
What does the lancefield test base species of strep to?
Cell wall CHO’s (A,B,C,D,E,F,G,H)
What are the Sreptococcus cell-associated virulence Factors
Capsules*
Peptidoglycan
Teichoic/lipoteichoic acid
M Protein*
Ig Binding Proteins
Streptokinase- converts plasminogen–> plasmin- breaks down fibrin
Streptococcal pyrogenic exotoxins (superantigens)
What is scarlet fever and why bother?
S. pyogenes Red rashy bumps Rheumatic fever Kidney disease (poststreptococcal glomerulonephritis) Otitis media Skin infections abscesses of the throat Pneumonia Arthritis
What species does S. Pyogenes effect?
humans cattle horses
What does S. agalactiae cause?
mastitis
S. equi subsp equi causes?
Strangles
S. uberis causes?
Clinical mastitis
S. canis is in which streptococcal group?
G
Where is S. Canis found?
commensal of skin and mucous membrane
What is S. canis infection consistent with?
Vagina or umbilical vein-> peritoneal cavity -> Liver -> wham bam thank you maam you got yourself bacteremia
S. canis infections can cause what in regards to the heart and lungs?
Septicemia and embolic lesions
What is the pathogenic Streptococcus associated with pigs?
S. suis
How many serotypes of S. suis are there
35
Which serotype of S. suis is most commonly isolated in pigs? and what about humans?
type 2 for both.
which age group of pigs are predominately bothered by S. suis?
weanlings and growing pigs
What are the clinical diseases brought about by S. suis?
Septicemia, serositis, meningitis, polyarthritis, pneumonia, abortions, abscesses and endocarditis
What species of Strep. is important to fishermen?
S. iniae- high zoonotic risk. virulent and commensal strains
What causes jowl abscess in pigs?
S. porcinus
Whats important about Viridans group of Streptococcus?
They do not react with lancefield grouping sera.
Definitive species ID is difficult.
Some human infections
Where can Viridans group ostrep be found?
mouth, Gi and Vagina of healthy humans as well as animals. Dairy and other sources
Streptococcus pneumoniae causes what in humans? and what does the human need to be to susceptible?
pneumococcal pneumonia, septicemia, and meningitis.
Older or immunocompromised
Who acts as the carrier of S. pneumoniae?
Domestic pets
S. equi belongs to which strep group?
Beta hemolytic Group C
What does S. equi look like?
usually has marked mucoid appearance due to hyaluronic acid Capsule
S. equi sbusp. equi has to be distinguished from other equine group C strep species ( S. zooepidemicus and S. equisimilis) what tests allow this?
Sugar fermentation or nucleic acid-based testing
S. equi infections are prone to which species of animal?
Equids are only known host
Which age group of horses is common with S. equi infections?
Weaned foals and yearlings are most susceptible
What are the virulence factors of S. equi?
Cellular- = hyaluronic acid capsule* =M protein * = IgG Fc Binding proteins =peptidoglycan/teichoic acid Extra cellular- -streptokinase -hyaluronidase -streptolysin S -DNAse -Streptococcal Pyrogenic Exotoxins
Strangles in horses what is it?
Abscessation of regional lymph nodes in the intermandibular area (retropharyngeal). caused by S. equi subsp equi
Transmission of S. equi happens how? and how contagious is it?
Direct= contact with horse shedding bacterium
Indirect= contact with contaminated enviornment
HIGHLY CONTAGIOUS
When do clinical signs appear after S. equi infection and what are the clinical signs?
3-14d Fever first 39-39.5--> look up conversion to F purulent nasal discharge depression, anorexia, dysphagia MOIST cough- love that word!! lymph node abscesses w/ in 2 weeks
What are two potential complications associated with S. equi?
Disseminated infection (bastard Strangles) Purpura Hemorrhagica (immune complex mediated vasculitis) TYPE 3 hypersensitivity reaction.
what the heck is a guttural pouch empyema?
Pus in the guttural pouch. which to my next point any time you put pus in a medical record please for the love of GOD do not put anything but pus.
What type of infection is GPE gut pouch empyema
Secondary to an upper respiratory infection
S. equi most common
retropharyngeal LN-> guttural puches through lymphatic drainage & rupture
Guttural pouch Chondroids
accumulation of soft or hard concretions in one or both guttural pouches
- chronic empyema
Carriers of S. equi usually shed how?
Incubatory 4-7 days after exposure w/ or w/ out clinical signs
Clinical shedding from affected sites
Convalescent nasal shedding for up to 6 weeks after recovery
Long Term shedding from guttural pouch 5-7 months or more
What is recovery and immunity to further infections of S. equi like?
Infected animals usually recover after abscesses mature and rupture
75% of animals have strong immunity following recovery
What are the diagnostic tests for S. equi?
CULTURE- Swab, Lavage (nasal, pharynx, LN, GP)
-3 negatives at weekly intervals sufficient to release from quarantine
-test GP 30d post recovery
SEROLOGY- ELISA for M Protein
PCR- M Protein= VERY GOOD TEST- determines asymptomatic carriers. MUST CONFIRM W/ Culture (PCR Detects live and dead Bacteria)
What is the treatment For S. equi?
most recover spontaneously
Symptomatic treatments to relieve pain and hasten recovery
ABX only effective if given prior to abscess formation
Is S. equi a reportable disease?
in many states yes, yes it is.
What is good common sense for S. equi control?
Quarantine
Isolation
Clean and disinfect
Scan herd to determine disease state on farm
Are there vaccines for S. equi?
Yes im glad you wanted to know there are 2!
Killed, IM (M Protein enriched) - Anti M protein antibodies
Live, IN used to stimulate mucosal immunity (can complicate culture based screening)
Where do enterococcus live?
GI tract
How does one become infected with enterococcus?
Nosocomial systemic infections
What else is important with Enterococcus?
Persistent UTI
Vancomycin resistance pathogenicity island
in vivo resistance
