Lecture 6 Flashcards
S.agalactiae: Lancefield type, hemolytic, arrangement, and Gram type?
Lancefield B, Beta or non-hemolytic, long chains, Gram-positive
S.agalactiae site of infection?
upper respiratory tract and genitourinary tract
When does infection of newborns by S.agalactiae occur?
At time of birth
Neonatal diseases associated with S.agalactiae?
pneumonia, bacteremia, sepsis, meningitis
infections in pregnant women associated with S.agalactiae?
urinary tract infection, bacteremia
Viridians Streptococci site of infection?
asymptomatic colonisation of the oropharynx, gastrointestinal tract, genitourinary tract, commensales of mouth flora (S.mitis, S.mutants)
Is Viridians Streptococci more virulent than S.pyogenes?
No, as they have less immune evasion toxins. some have adensins/pili for binding to teeth and produce biofilm (dental plaque)
Diseases with Viridians Streptococci?
Dental diseases: S.mutants, S.sobrinus
Bacterial endocarditis: S.gordonii, S.mitis
septic shock in immuno-compromised Px’s
Streptococcus pneumoniae shape and arrangement? outer capsule or no capsule?
‘Lancet-shaped’ diplococci, most strains have outer capsule
Streptococcus pneumoniae spread from where to where?
Pharynx to lungs, sinuses, ears
Streptococcus pneumoniae virulence factors?
antiphagocytic capsule and produces pneumolysin (a cytolysin that destroys ciliated epithelial cells)
Diseases associated with Streptococcus pneumoniae?
Pneumonia (60% of bacterial pneumonia), meningitis (headache, fever, sepsis, high mortality, children and elderly), bacteremia, sinusitis and otitis media (secondary infection)
Diagnostic of Streptococcus pneumoniae
alpha, hemolytic on blood agar, Gram-positive, negative catalase, sensitive to optochin, Gram-positive diplococci
Group D (Enterococcus spp.) site of infection
gastrointestinal tract
Risk factors for Group D (Enterococcus spp.) spreading
broad-spectrum antibiotic use (as it affects normal gut flora), prolonged hospitalisation
