gram negative bacteria Flashcards
what are pathogenicity determinants?
any product or strategy hat contributes to pathogenicity/ virulence
what are colonisation factors?
adhesins, invasins, nutrient acquisition, defense
what are toxins?
usually secreted proteins -> damage, subversion
name two main pathogenicity determinants
clonisation factors
toxins
describe coliforms
Enterobacteriaceae or Enterobacteria
Rod-shaped
Motile (most)
Peritrichous flagella
Facultatively anaerobic
what do coliforms do?
Colonise the intestinal tract
Advantageously or disadvantageously
what are the diagnostic characteristics of gram negative pathogens?
Enterobacteriaceae consists of multiple Gram negative rod-shaped bacterial species
Metabolic processes of bacteria can help diagnosis
Lactose fermentation produces acids
Distinguishes Escherichia coli and Klebsiella sp.
what gives rise to antigenic variation among species and between isolates (strains) of the same species
Amino acid or carbohydrate variation in cell surface structures
what are the principal infections caused by pathogenic E. coli
-Wound infections (surgical)
-UTIs
-Cystitis
-75-80% of female UTIs –faecal source or sexual activity
-Catheterisation – most common type of nosocomial infection
-Gastroenteritis
-Travellers’ diarrhoea
-Bacteraemia (potentially sepsis syndrome)
-Meningitis (infants) – rare in UK
what are the 4 major groups of gram negative pathogens?
1.Proteobacteria
2.Bacteroids
3.Chlamydia
4.Spirochaetes
describe proteobacteria
all are rod-shaped
describe bacteroids
rod shaped
describe chlamydia
round pleimorphic
describe spirochaetes
spiral/ helical
what makes a pathogen difficult to culture in the lab?
The dependency of a pathogen on its host can make it very difficult to culture in the lab
