Microbes & Infection Model Flashcards
What are the key features of bacteria?
lack of membrane-bound organelles, unicellular, small
What are the key features of viruses?
Enclosed in protective envelope
spikes = attach to the host cell
non-cellular
do not respire, do not metabolize, do not grow, do reproduce
protein coat = capsid, contains genetic material
What are the key features of fungi?
multicellular, eukaryotic, heterotrophs = gain nutrition through absorption
How are microorganisms classified?
Classified by taxonomy, name = genus + species
List the micro-organisms in order of size
Prions, proteins, viruses, mycoplasma/clamydiae/rickettsiae, mitochondria, bacteria, eukaryotic cells (yeasts, protozoa, human cells), worms
What is a prion?
Protein that causes brain degeneration e.g. CJD
What microorganism is macroscopic?
Worms
Describe the genetic material of viruses
Can be ss or ds, to replicate the genome viruses need to be inside a host cell to utilise their replication processes
What does the baltimore classification of viruses tell us?
That there is a huge diversity of viruses
Give an example of a ds non-enveloped DNA virus
Adenovirus = res tract infections
HPV = cervical cancer
Give an example of a ds enveloped DNA virus
Epstein-barr virus
What are the shapes of bacteria?
Coccus, spirillus, bacillus/rods
What 2 arrangements can cocci be in?
Clusters or chains
What makes a bacteria gram +ve or –ve?
peptidoglycan, in cell wall of Gram +ve bact
Gram +ve bact retain crystal violet dye, Gram -ve bact do not
Crystal voilet, iodine, alcohol washing, counterstain safranin, stain Gram -ve bact pink
Both Gram +ve and Gram -ve bact pick up counterstain but is unseen on Gram +ve bact due to darker crystal violet stain
Outline the types of oxygen tolerances
Aerobes = survive in O2.
Anaerobes = survive in no O2.
Obligate = require for survival
Outline some diff between eukaryotes and prokaryotes
E = multiple chromosomes, nucleus membrane bound, membrane bound organelles, no peptidoglycan.
P = circular DNA, plasmids, no nuclear envelope, no membrane bound organelles, cell wall has peptidoglycan
What is the difference between an exotoxin and endotoxin?
Exotoxins are toxic substances secreted by bacteria and released outside the cell.
Endotoxins are bacterial toxins consisting of lipids that are located within a cell
Outline the general areas of virulence
Host entry/exit Adherence to host cell Immunosupression Immunoevasion Iron sequestration Toxins
Outline the key stages in the model of infection
Patient meets pathogen, differing mechanisms of infection = infection followed by management then outcome
Expand on the pt part of the infection model
Person: age, gender, physiological state, pathological state, social factors
Time: calendar time (seasons), incubation period.
Place: current, recent
Expand the infection part of the infection model
infection –> attachment –> toxin prod/interaction with host defenses –> inflam = host damage
Expand the management part of the infection model
History (for diagnosis) Examination (for diagnosis) Investigations (for diagnosis) Treatment (specific or supportive) Infection prevention
What 2 areas can treatment be broken down into?
Specific = antimicrobials, surgery, drainage, debridement, dead space removal (hole after drainage/debridement infect can occur)
Supportive = symptom relief, physiological restoration
Name the 7 mechanisms of infection
Contiguous (direct) Inoculation Haematogenous Ingestion Inhalation Vector Vertical
