Epidemiology Flashcards
Why might you get a reduction in the diversity of microbial population?
Because of periodic selection, and bottlenecks.
What two things can affect the clonality and diversity of bacterial populations?
Rates of mutation and horizontal gene transfer in bacteria.
Example of bacteria with very high clonality and diversity?
Salmonella enterica
Example of bacteria with very low clonality and diversity
neisseria gonorrheoae
Bacteria with mid-levels of clonality and diversity?
N. meningitis, Staph aureus, and strep pneumoniae.
What meningococcus causes meningococcal disease?
N. meningtitis.
what does meningitis describe?
inflammation of the meninges (tissues around the brain)
What two things can invasive meningococcal disease IMD caused by N. meningitidis cause?
menintgitis or septicaemia.
What levels do we look at to describe Neisseria populations?
Serogroup, serotype, lineage.
What determines serogroup? What genetic test for it?
capsule, genotype the cps region.
What determines Neisseria serotype and genetics?
The outer membrane proteins. porA, porB, fetA
What determines Neisseria lineage, sequencing?
the housekeeping genes, use multi locus sequence typing (MLST).
Why is there a peak in invasive meningococcal disease in infants and adolescents?
Because of immature immune system.
Could be because carriage increases, and type of lineage that causes disease increases.
What effect did the introduction of the MCC vaccine have on endemic before 2000s
Decreased the proportion of meningococcal gorup C being carried (as well as group B).
Why was there an outbreak of meningococcal disease in Us army?
Change in carriage from B to C (unlikely to be causative), outbreak due to resistance against sulphamides, controlled with plain C polysaccharide vaccine.
