Catalase and peroxidase – removal of hydrogen peroxide
Types of healthcare associated infections (HAIs)
Exogenous - Pathogen acquired from the health care environment
Endogenous - Pathogen arises from normal microbiota as a result of factors within the
healthcare setting
Iatrogenic - Results from modern medical procedures
Superinfections - Use of antimicrobial drugs reduces competition from some resident
microbiota, allowing other microbes to thrive
, Know the characteristics of prokaryotic cells – i.e. no nucleus
1. they have no nuclear membrane
2. their DNA is not wound around histones
3. the cell walls are made of a chemical called peptidoglycan
4. they do not have complex membrane-bound organelles
What does prokaryotic mean?
Any unicellular microorganism that lacks a nucleus. Classification includes bacteria and
archaea.
Know how we measure bacterial cells.
The standard method is the plate count, which is the usual way to count microbes. The purpose
of this method is to just use a sample of dilutions on a bacterial culture and counting. First, 3 of
the 0.1ml dilutions are poured to duplicate the agar plates. One then sterilizes the glass spreader
by dipping it in alcohol and burning it. Once the spreader is cooled, 0.1 of the inoculum is spread
over the agar plates till the media doesn’t look wet. Repeat the process for the remaining plates.
Once all that is done, it must be incubated at room temperature. It can then be counted in the end,
all of the colonies. The advantage of this method is that it is super easy to do and one counts
CFUs if they aren’t broken up. It isn’t complicated to pull through this method. As for the
disadvantage, the count might not be as accurate. Not only this, the time to complete this method
with all the dilutions, plating, smearing, and incubation waiting take a bit of time.
The turbidimetric method is a much more complicated process. This process deals with the
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