Introduction into Gram Negative Bacteria Flashcards
- Identify all of the genera of Gram-negative bacilli listed on p2-3 of this unit and associate each with its major disease syndromes.
Sepsis: Escherichia, Klebsiella, Enterbactor, Proteus
Pneumonia: Klebsiella, Serratia, Enterobacter, Escherichia
Meninigitis: Escherichia
UTI: Escherichia, Proteus, Providencia
Gastroenteritis: Salmonella, Shigella, Scherichia, Yersinia
Intra-abdominal infection: Escherichia
Bordetella pertussis- tracheobronchitis, whooping cough
Campylobacter- gastro enteritis
Hamophilus: URI, OM, meningitis, sepsis
Helicobacter: gastritis, ulcers, gastric cancer
Moraxella: URI, OM
Neisseria: genital tract infection, STI (N. gonorrhoeae); nasopharyngeal colonization, meningitis, sepsis (N. meningitides)
Pseudomonas- opportunistic lung, skin, eye, burn wound, blood infection
Vibrio- gastroenteritis, skin lesions
- Identify the range of nonpathogenic and pathogenic niches of of E.coli
gram negative rod, facultative with different phenotypes resulting form different genomic features
normal bowel microbiota
enteric pathogens: EHEC, ETEC, EPEC
urinary tract- UPEC
bloodstream and central nervous system of neonates
sporadic infections of lung, peritoneal cavity
laboratory tool
- Identify the range of human and nonhuman sources of E.coli.
obligate human pathogens: (oral fecal transmission) S. typhi, Shigella, Helicobacter pylori, Entamoeba histolytic
zoonotic pathogens: E. coli (ground beef), Non-typoid Salmonella (poultry, eggs, pet reptiles), Campylobacter (poultry, milk), humans also a source through fecal/oral transmission
- Describe the types of infections caused by E.coli and their clinical significance.
Sepsis: Escherichia, Klebsiella, Enterbactor, Proteus
Pneumonia: Klebsiella, Serratia, Enterobacter, Escherichia
Meninigitis: Escherichia
UTI: Escherichia, Proteus, Providencia
Gastroenteritis: Salmonella, Shigella, Scherichia, Yersinia
Intra-abdominal infection: Escherichia
- Identify the 5 types of virulence determinants described in this unit that are commonly shared- Adhesion.
great variety of variation, obviously an important feature: fimbriae, pillus, etc
important feature to compete with the host defense of unidirectional flow
people can have differing susceptibilities for UTI base on expression of particular receptors, Cranberry juice contains receptor blocking molecules
- Identify the 5 types of virulence determinants described in this unit that are commonly shared- Host defense evasion or resistance.
K antigen capsules are antiphagocytic, can block binding of macrophages and complement, esp. if capsule is not immunogenic
microbial biofilms (secretion of polysaccharide matrix) are important in colonization of niches in host and establishment/continuation of infection
- Identify the 5 types of virulence determinants described in this unit that are commonly shared-Nutrient acquisition.
common mechanism is iron withholding or other mechanisms to reduce the ability of organisms to acquire nutrients needed for growth
- Identify the 5 types of virulence determinants described in this unit that are commonly shared- Mediators of host damage.
mostly produced toxins (ie. enterotoxin) that can modulate the intracellular signaling pathways (cyclic AMP, GMP, phosphorylated phosphoinositides, Ca2+ and cytoskeleton pathways)
- Identify the 5 types of virulence determinants described in this unit that are commonly shared- Specialized mechanisms of resistance.
acid tolerance- growth in stomach
ability to grow well in urine
motility
- Discuss the 3 genera of Enterobacteriaceae that cause urinary tract infection, including E.coli as the major cause of UTI.
E. coli (uropathognic UPEC)
Proteus spp. (mirabilis in CA or in care facilities)
Providencia spp.
also Klebsiella, Serratia, Staph saprophyticus, candida albicans
- Describe the role of polysaccharide capsule as a virulence determinant for bacterial meningitis.
E. coli is the #2 cause of neonatal meningitis in vaginally delivered infants, specifically K1-encapsulated E. coli
host defense can mount an anti capsular defense, except in cases like capsules made from Sialic acid where material is found elsewhere in humans and seen as a “self antigen”
- Explain how K1 E. coli causes neonatal meningitis.
k1 capsule is a polymer of sialic acid, and this is a molecule that is abundant on the surface of mammalian cells and humans are immunologically tolerant so they don’t raise a good antibody response against K1 capsule
- Describe the clinical features of pneumonia caused by Enterobacteriaceae such as Klebsiella and Serratia.
severe pneumonia with purulent sputum, may progress to necrosis, hemorrhagic pneumonia, abscess
ie. Klebsiella is known for current jelly sputum
