Streptococcus And Enterococcus Flashcards
Gram Positive cocci that are catalase -?
Catalase +
Streptococci
Staphylococci
Streptococcus morphology
Gram + cocci in strings
Beta hemolytic Streptococcus
A, B, C, F, G (Types using Lancefield grouping)
alpha hemolytic streptococcus
Strep Virginians and Strep pneumoniae
Gamma hemolytic strep
Group D strep and enterococci
Group A strep
Strep pyrogens
Rhamnose-N-acetylglucosamine polysaccharide
Group B strep
Strep agalactiae
rhamnose-glucosamine polysaccharide
Group A strep diseases
Suppurative (pharyngitis, impetigo, cellulitis/bacteremia, scarlet fever)
Non-suppurative (rheumatic fever, acute glomerulonephritis)
Group A strep- pharyngitis
Most common bacterial infection in children
Inflamed pharynx and tonsils-white exudate
Tender lymph nodes
Fever 101 or higher
Diagnose with culture or antigen tests
Streptococcal skin infections-impetigo
Climate and hygiene most important factors
Colonize unbroken exposed areas
Small wet patches of red skin that wrap fluid
Children: Peak 2-5 years
Highly contagious
Strep skin infections- erysipelas
Acute infection
Painful, erythematous, sharp raised borders
Fever
Leukocytosis
Strep skin infections- cellulitis
Spreading infection of skin and subcutaneous tissue
Painful, less distinct borders than erysipelas
Fever
Leukocytosis
Burn victims
Wounds, drug use
Strep skin infections- necrotizing fasciitis
Teper subcutaneous tissues and fascia
Flesh eating bacteria
Infection with rapid spread via the facia characterized by severe pain
 cellulitis gangrene necrosis
Fever, leukocytosis, hypotension, shock multi organ failure
Treatment involves aggressive surgical debridement plus antibiotics and IVIG
High mortality rate 
Strep skin infections- scarlet fever
Associated with strains that produce SPE- streptococcal pyrogenic exotoxin
Appears on first day following acute infection
Rash on chest then sandpaper texture to skin
Rash fades then extensive desquamation lasting approximately a week
strawberry tongue
pastia’s lines
Toxic shock syndrome
Multi organ failure
Seen following pneumonia or necrotizing fasciitis
Streptococcal pyogenic exotoxins (SPEs)
Rheumatic fever
Follows untreated group A streptococcal mediated pharyngitis
Involves, heart joints, subcutaneous tissues
Where in US but common in under developed world
Involves cross reactive antibodies
Glomerulonephritis
Inflammatory disorder of renal glomerulus
Rare complication of S pyogens
Follows pharyngitis or pyoderma caused by certain strains of group A streptococci
Cross reactive antibodies or immune complexes are possible disease mechanisms
Pediatric auto immune neuropsychiatric disorders associated with streptococcal infections (PANDAS)
Immune sequel are of GAS: antibodies attack basal ganglia
Sydenham’s chorea
Tourette’s syndrome, tics, OCD
Mechanisms of pathogenesis
Antimicrobial peptide resistance
opsin resistance
phagocyte apoptosis
biofilm formation
epithelial cell adherence and invasion
destruction in neutrophils
dissemination and systemic infection
Outcomes of Group A Streptococcus infections
PANDAS
Rheumatic fever
Glomerulonephritis
Toxic shock syndrome
Necrotizing fasciitis
Erysipelas
Scarlet fever
Impetigo
Pharyngitis
Treatment of Streptococcus infections
Penicillin (must take full corse due to suppression of post-streptococcal non-suppurative sequelae)
Group B strep
S agalactiae
Major cause of disease in neonatal and perinatal periods
Early onset- passage through colonized birth canal
Late onset- nosocomial infection
Positive CAMP reaction indicates
Group B strep (S agalactiae)
Group C strep
S dysgalactiae
Causes pharyngitis and other disease (skin/soft tissue, sepsis)
Group F strep
S anginosus group (anginosus, constellatus, intermedius)
Brain abscess, liver abscess, peritonitis 
Group G strep
Cross reacts with S anginosus group or S dysgalactiae)
Group C, F, and G Strep are all susceptible to _
Penicillin
Streptococcus pneumoniae
Community acquired- CAP
Adult meningitis
Sinusitis, otitis media, bacteremia
Streptococcus pneumoniae virulence
Polysaccharide capsule
94 different types anti-capsular antibody is protective
Higher incidence of pneumonia in those with clearance issues
Bacterial and host factors affecting pneumococcal shedding
pneumocystis, capsule type and amount, and viral co-infection increase shedding
Anticapsule IgA1 has no effect
Anticapsule IgG decreases shedding
Optichin susceptible Streptococcus are _
S pneumoniae
Optochin resistance Streptococcus are _
Other alpha hemolytic strep
Prevention of pneumonia
Pneumococcal vaccine
13 valent and 23 valent directed at capsule
S pneumoniae can become resistant to penicillin
Streptococcus Virginians
Alpha hemolytic strep
Part of normal flora in upper respiratory tract
Penicillin resistance
Enterococci
Used to be streptococcus
Normal gut flora
E faecalis and E faecium infections occur in compromised hosts (UTI, bacteremia, endocarditis)
Streptococcus antibiotic resistance
Vancomycin resistant strains (VRE) usually multi resistant
VRE can be treated with synergies/Linezolid/daptomycin
VRE is a nosocomial problem
Transfer of vancomycin resistance to S aureus is a major concern
Group D non-Enterococci-Streptococcus Boris group
Non hemolytic
Normal flora in GI tract (S equines, S gallolyticus, S infantarius, S alactolyticus)
S gallolyticus subspecies causes endocarditis and bacteremia associated with colonic cancer or meningitis
Penicillin susceptible
