Gram Pos Cocci- Staphylococcus/Strep Flashcards
What is the cell wall of gram pos
thick wall of Petidoglycan in their wall
What type of aerobes are gram pos cocci and are they intra/extracellular pathogens
Faculative anaerobes
Primally extracellular
What are the types of blood agar lyses
B hemolysis- complete
A hemolysis- partial (causing green)
Y hemolysis- no lysis
What are the 2 tests to categorize g+ cocci
- Lancefield cell wall antigens
2. coagulase test (will be +)
Group A streptococcus- type of lysis, Antigen type, motility, Capsule +/-
B hemolytic
Group a lancefield antigen on cell wall
Non motile
Produce a capsule
What is the repersentative human pathogen + mc associated disease
Steptococcus pyogen
=Stretococcal pharyngitis
Assiciated diseases of streptococcus pyogens (5)
- step pharygitis
- Steptococcal skin inf
- Scarlet fever
- Step toxic shock syndrome
- post steptococcal complication
Streptococcal pharygitis- target, transmission, pathology, antibiotic
target- primarly children
transmission- large respiratory droplets
Pathology- abrubt sore throat, swollen lymph nodes, exudate, fever
Antibiotic- b lactams
what are the 3 types of streptococcal skin infections
- Impetigo
- cellulitis
- Necrotizing fascitits
Impetigo- age, symptoms, area of effect
Infection of superficial layers of skin epidermis
(highly contagoius)
-causes red sores that rupture, honey coloured crust around nose/mouth
Cellulities- symtoms/areas affected
rapid spreading infection of dermis + subcutenous fat in skin (skin may be swollen/warm)
-associated with burns, wounds, ulcers +surgical insision
Necrotizing fasciitis (flesh-eating disease)- symptoms, area affected, why
Inf that spreads into deeper subcutaneous tissue of skin/muscles/fascia casuing skin changes
- @ site of trauma or insision
- Severe pain, fever, weakness etc
What is scarlet fever due to
s pyogens strains that produce steptococcal pyrogenic exotoxins (spe)
what is the clinical picture of scarelet fever
Super antigens prodice inflammatory response that causes bumpy, bright red rash under skin
+fever
What triggers streptococcal toxic shock syndrome and what are the clinical effects
super antigens (spe) enter blood and activate up to 20% of t cells resulting in cytokine storm
- sustematic vessel leakiness, fever, multisytem organ involvement
What are examples of post streptococcal complications (3)
- Acute rheumatic fever (fever, inflamed jts, heart issues)
- Post infectious glomerulonephritis (pharyngitis/skin inf)
- PANDAS- ocd, anxiety etc
what type of blood agar does group b step: strep agalactica have
B hemolytic
How is steptococcus agalactiae transfered and who does it affect + cause
neonates from mothers thru infection of genital tracts
- Can cause neonatal pneumonia + meningitis
- also effects at risk elderly
Streptococcus mutans blood agar type and what is it the primary cause of
a hemolytic
Primary causes of dental cavities, plaques, abscesses
how does streptococcus mutans cause dental plaque (and what is a risk of infection)
S mutans metabolize sucrose producing sticky strands that allow them to adhere to teeth
- risk of endocarditis
Streptococcus pneumoniae blood agar type, and where is it usually colonized
a hemolytic
nasopharyngeal colonization (usually asymptomatic)
what is a serotype of a bacteria
Serotype: if strains of a bacterial species are so different that they induce different antibody responses, those strains are said to be serotypes (same species but immune system responds differently)
how is streptococcus pneumoniae transmitted and how does it evade host response
transmitted via respiratory droplet or direct contact
all serotypes produce a slightly dif polysaccharide capsul that impairs host phagocytosis
What is the most common cause of pneumia in adults + community aquired pneumia
Streptococus pneumoniae
