Bacteria Flashcards
(20 cards)
Strep is …
Staph is …
Strep is chains
Staph is bunches
Neisseria Meningitides
Gram negative, Diplococci, meningococcal sepsis
VF = Lipopolysaccharide
Nasopharyngeal swab
Treatment:
Ceftriaxone (for meningococcal sepsis, good CSF activity)
Penicillin V
E. Coli (Escherichia Coli)
Gram negative, Bacilli - commensal at colon
(also causes Peritonitis)
Treatment:
UTI’s = Trimethoprim
Neonatal meningitis = Cefotaxime
Staph Epidermidis
Gram positive, cocci - commensal for skin
Forms slime - quorum sensing - difficult to remove
Treatment:
Flucloxacillin (if cellulitis)
Remove prosthetic device - use silver coated central lines
What is quorum sensing?
Quorum sensing is the regulation of gene expression in response to fluctuations in cell population density.
Quorum sensing bacteria produce and release chemical signal molecules called autoinducers that increase in concentration as a function of cell density?
Strep pyogenes - Group A strep
1/2
Gram positive, cocci
Common cause of pharyngitis/tonsillitis
Impetigo, Erysipelas, Cellulitis, Necrotising fasciitis
Treatment Penicillin V (Clarythromycin if resistant)
Strep pyogenes - virulence factors
2/2
Hyaluronic acid capsule (makes it poor immunogen, seem like “self”)
M protein (hijacks respiratory burst mechanism of neutrophils)
Streptokinase (breaks down blood clots)
Hyaluronidase (breaks down hyaluronic acid)
C. Difficile
1/2
Gram positive, bacilli - colon commensal
Sporulating (difficult to get rid of)
Treatment:
Metronidazole (mild)
Vancomycin (serious)
C. Difficile virulence factors
2/2
Toxin A (enterotoxin) = causes inflammation and build up of excess fluid in bowel = diarrhoea
Toxin B (cytotoxin) = disrupts protein synthesis and disrupts cytoskeleton
Strep pneumoniae - Gram stain and treatment
1/2
Gram positive, diplococci but may be seen in short chains
Treatment
Mild = Amoxicillin - doxycycline if allergy
Moderate = Amoxicillin & Doxycycline (doxycycline only if allergy)
Serious = Co-amoxiclav (IV) & Doxycycline (meropenem & doxycycline if allergy). ALL ABOVE CELL WALL SYNTHESIS INHIBITORS
Strep pneumoniae - virulence factors
2/2
VF = polysaccharide capsule (serious virulence factor)
Note:
It is a member of the viridans group of streptococci
Cause of community acquired pneumoniae
Viridans Streptococci
Gram positive, cocci - oral commensal (e.g. S. Mutans)
Alpha haemolytic usually
Tooth decay, bacterial endocarditis
Treatment = surgical antibiotic prophylaxis
Haemophilus Influenza
Gram negative, coccobacilli (bacilli) - Nasopharyngeal commensal
Associated with children & especially pneumonia
Treatment = amoxicillin
Salmonella Typhi
Gram negative, Bacilli with flagella
Typhoid or Enteric fever
Travel related infection (contaminated water, faecal-oral route)
Treatment:
Ceftriaxone (recommended for elderly)
(Fluoroquinolones can be used)
Legionella Pneumophila
Gram negative, bacilli
Legionnaires disease - air droplet transmission
can cause: Acute lobar pneumonia
Treatment:
Clarythromycin (or fluoroquinolones)
Staph Aureus
Gram positive, cocci, skin commensal,
Treatment:
Flucloxacillin - cellulitis (not MRSA
Vancomycin - MRSA
both above cell wall synthesis inhibitors)
List the gram positive cocci - PURPLE STAIN
Staphylococcus Aureus Staphylococcus Epidermidis Streptococci Pneumoniae Viridans Streptococci Streptococcus Pyogenes
List some gram positive bacilli - STAIN PURPLE
Clostridium Difficile (C. Diff)
(Listeria monocytogenes)
(Bacillus anthracis)
List some gram negative cocci - STAIN PINK
Neisseria Meningitides
Neisseria Gonorrhoeae
List some gram negative bacilli - STAIN PINK
Escherichia Coli (E.Coli) Klebsiella Pneumoniae Haemophilius Influenzae Salmonella Typhi Legionella Pneumophila
