Escherichia coli: Overview
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Escherichia coli Overview
- Characteristics
- Gram negative rod
- motile
- Indole +
- Lactose-fermenting
- Grows on eosin methylene blue (EMB) agar, where lactose fermentation produces a blue-green color
- Can also ferment glucose
- Facultative anaerobic
- Gram negative rod
- Presentation
- Over 100 strains cause disease
- Each strain has different virulence factors, which determines disease
- UTI
- most common cause of UTI (>80%)
- Mediated by pili/fimbriae
- enable adhesion to uroepithelial surface
- May present as cystitis, urethritis, or pyelonephritis
- Diarrhea
- ETEC causes watery diarrhea
- EHEC causes bloody diarrhea
- enteroinvasive E. coli (EIEC) strains are rare cause
- Neonatal Meningitis
- Mediated by K1 capsule
- Prevents phagocytosis or complement activation
- Sepsis
- Most common cause of gram-negative sepsis
- Mediated by LPS endotoxin
- seen in all gram-negative bacteria
- May be causative agent in a variety of other infections
- osteomyelitis in sickle cell patients
- intra-abdominal and lung abscesses
- orchitis in older men
- Over 100 strains cause disease
- Treatment
- Generally supportive, as antibiotics are rarely indicated