Lab Exam Flashcards
Steps of Scientific Method
- Observations lead to a question
- Hypothesis
- Experiments test the hypothesis
- Based on experimental results, the hypothesis is:
Accepted, Rejected, or Modified
Medium
Collection of nutrients for culturing microbes
Culture
Act of cultivating microbes, medium in which a microbe is cultured, describes medium
Defined (synthetic) media
Every chemical and its concentration is known, e.g. medium for culturing E. Coli
Complex Media
Contain imprecise kind or amount of one or more chemicals, e.g. nutrient broth/agar, MacConkey, trypticase soy agar
- can be enriched by blood
Selective Media
Enhance the growth of selected microbes while inhibiting the growth of others, e.g. Sabouraud dextrose and MacConkey
Differential Media
Appear different when various microbes grow on them, e.g. citrate agar and carbohydrate utilization broths, blood agar
Properties of Agar
- most microbes cant digest it
- does not melt below 100 degrees
- solidifies at below 40 degrees
Enriched Media
Uses a selective medium to increase small numbers of a chosen microbe to observable levels
Hemolysis
Partial (green halo) - alpha
Complete (clear halo) - beta
No lysis - gamma
Cell culture
Consists of cells isolated from an organism and grown on the surface of a medium or in broth, technique to cultivate host cells
Cytopathic Effect
Damage done to cell monolayer, characteristic of specific virus
Recommendations for Microbiologic Sampling
- water and dialysate fluid
- selective sampling in an outbreak
- hydropools
Guideline Rating System
A. Good evidence to support a recommendation for use.
B. Moderate evidence to support a recommendation for use.
C. Insufficient evidence to support a recommendation for or against use.
D. Moderate evidence to support a recommendation against use.
E. Good evidence to support a recommendation against use.
I Evidence from at least one properly randomized, controlled trial.
II Evidence from at least one well-designed clinical trial without randomization, from cohort or case-controlled
analytic studies, preferably from more than one centre, from multiple time series, or from dramatic results in
uncontrolled experiments.
III Evidence from opinions of respected authorities on the basis of clinical experience, descriptive studies, or
reports of expert committees.
RODAC plate
Replicate Organism Detection And Counting Plate: used for sampling flat surfaces
Aseptic Technique
Used to transfer bacteria from one medium to another without introducing other microbes into the culture or into the environment; designed to keep pure cultures of bacteria
Inoculum
Bacteria transferred from a culture to sterilized media
Pure culture
Contains only one type of bacteria
Axenic
Used to refer to pure culture
Colony-Forming Unit
Progenitor from which a pure culture is derived; either a single cell or a group of related cells
Streak Plate Technique
Used to separate a high concentration of cells into a single cell which replicates to produce an isolated colony (pure culture)
Inoculation
Introducing an inoculum to a sterile medium
