Streptococcus & Enterococcus Flashcards
What is Streptococccus?
Gram +, aerobic, catalase neg. cocci
Chaines in clinical samples
What is the habitat for Streptococcus?
Commensals of mucous membranes of humans and animals (not usually skin)
What is a key point of a streptococcal infection?
May be endogenous or exogenous, including species present as either commensals or in a carrier state, and some are contagious
Are Beta hemolytic streptococci pyogenic?
Yes, generally
Are non-hemolytic or alpha hemolytic streptococci pyogenic?
No, non-pyogenic
What is the key point about pathogenic streptococci?
Tend to be host-adapted, and cause extracellular infections including septicemias, throat and adjacent lymph node infections, and pneumonias
What are the virulence factors of pyogenic streptococci?
Capsule, antiphagocytic
Anti-complementary surface proteins
Lytic enzymes
Toxins
Superantigens (Strep. TSS)
What causes strangles in horses?
S. equi subsp. equi
What is strangles?
Abscess formation in regional lymph nodes in head and neck
REPORTABLE
What are some characteristics of S. equi?
Beta hemolytic, Group C
Marked mucoid appearance due to abundant hyaluronic acid capsule
What are important factors about S. equi infection?
Contagious upper respiratory tract disease with abscess formation
Equids are only known hosts
What are 2 important S. equi virulence factors?
- Hyaluronic acid capsule
2. M protein
What are some clinical signs of S. equi?
CS appear 3-14 days after exposure
Fever, depression, anorexia, dysphagia, most cough, purulent nasal discharge
What are 2 major potential complications of S. equi?
- Bastard strangles/disseminated infection
2. Purpura hemorrhagica/immune complex mediated vasculitis
What is guttural pouch empyema?
Accumulation of purulent material in guttural pouch
Usually secondary to upper respiratory infection
What are guttural pouch chondroids?
Accumulation of soft or hard concretions in one or both guttural pouches, associated with chronic empyema
What are 4 types of carriers for S. equi?
- Incubatory
- Clinical
- Convalescent
- Long term
What is an incubatory carrier?
Nasal shedding begins 4-7 days after exposure w/or w/out clinically evident nasal discharge
What is a clinical carrier?
Shedding from affected sites; nasal, pharynx, lymph nodes, guttural pouch
What is a convalescent carrier?
Nasal shedding for up to 6 weeks after recovery
What is a long term carrier?
5-7 months or more, mostly from guttural pouch
What are 3 ways to DX S. equi?
- Culture
- Serology (not widely used)
- PCR
How would you treat symptomatic animals with a S. equi infection?
TX to relieve pain and hasten recovery
How effective are antibiotics in TX of S. equi infections?
Only effective if given soon after exposure and before abscess formation
When do infected animals usually recover from S. equi infection?
Usually after abscesses mature and rupture
Is S. equi reportable?
Yes, reportable in many states
What are 2 vaccines used for S. equi?
- Killed S. equi vaccines
2. Live, intranasal S. equi vaccine
What is a killed S. equi vaccine used for?
Used in pregnant mares and foals to maintain high levels of anti M protein opsonizing antibodies
What is a live attenuated S. equi vaccine used for?
Used to stimulated mucosal immunity & serum opsonization antibodies
What is pyogenic streptococci?
Beta-hemolytic strepococci from animals; can cause disease in humans occasionally
What is mastitis in animals caused by?
Streptococcus agalactiae
What is important about S. agalactiae?
Obligate parasite of mammary gland of cows
Infected cows are reservoir for infections
Contagious
What kind of host range does S. equi subsp. zooepidemicus?
Broad host range
What kind of pathogen is S. equi subsp. zooepidemicus?
Opportunist pathogen
What kind of infections does S. equi subsp. zooepidemicus cause?
Purulent infections in animals, upper respiratory tract infections, pneumonia, assesses, wounds, UTI, mastitis, foal septicemia etc.
What is S. pyogenes: Group A streptococcus?
Flesh eating bacteria
What group does Streptococcus canis belong to?
Group G streptococcus
Is Streptococcus canis a commensal?
Yes, of skin & mucous membrane (especially in reproductive tract)
What can S. canis infect?
Vaginal or umbilical vein > peritoneal cavity, liver > bacteremia
What kind of lesions does S. canis cause?
Septicemia and embolic lesions in heart and lung
What kind of clinical signs are seen with S. canis?
Skinulcerations, chronic respiratory infection, necrotizing sinusitis and meningitis, necrotizing fasciitis w/skin ulcerations, TSS, sepsis, death
What animals are affected by S. canis?
Kittens and puppies
What animals are usually associated with S. suis?
Pigs
Who is affected by S. iniae?
Fish
What is newly recognized in S. iniae?
Zoonosis from fish
What kind of strains are there for S. iniae?
Both virulent and commensal strains
What is S. porcinus?
Jowl abscess in pigs
What is S. pneumoniae?
Pneumoccocal pneumonia, septicemia and meningitis in humans
Pneumonia in guinea pigs and rodents
Domestic pets can act as carriers
What is the Viridans group of Streptococcus?
A huge group that does not react with Lancefield grouping sera
How is Neonatal septicemia in foals treated?
Require colostrum
What would pyogenic Streptococci be treated with?
Penicillin G
What are Enterococci?
Normal intestinal flora
Low grade pathogens, true opportunists
What kind of infections do Enterococci cause?
Mastitis, would infections, UTI, secondary infections, Nosocomial infections
Why do some Enterococci species have emerging importance?
Because of nosocomial infections and innate resistance to antimicrobial drugs
