Exam 1 (Ch 7 Vocab, part 1/2) Flashcards
Cultivation of microorganisms
refers to the lab purposefully growing a pathogen for study, identification, or quality control uses
When cultivating them, the microorganisms’ needs must be met for what 3 things?
- Nutrients
- Atmosphere
- Temperature
If a microorganism is not cultivated correctly, it can interfere with ___ ___ and cause ___ ___ ___.
- proper ID
- negative patient outcome
Obligate anaerobe
harmed by O2
Capnophilic aerobe
needs both O2 and CO2
Capnophilic anaerobe
needs CO2, but is harmed by O2
Microaerophilic
- needs decreased amount of O2
- approximately 5%
Facultative anaerobe
grows without or without O2
Aerotolerant anaerobe
- tolerates O2 (but grows better without it)
Inoculation
the act of transferring a specimen to media
7 types of media
- General purpose (nutrient)
- Selective
- Differential
- Enrichment
- Transport
- Specialized
- Combination
General purpose/nutrient media
- meets most organisms’ basic nutritional requirements
- non-selective
- not all organisms will grow (special needs)
Example of nutrient media
- SBA (sheep blood agar)
- its nutrients includes RBCs
Selective media
- selective for desired microbe
- contains inhibitory agents
- can use:
#chemicals
#antibiotics
#dyes - results vary among different types of media
7 examples of selective media
- CNA (colistin-nalidixic acid)
- PEA
- HE
- CampyBA
- SSA
- TM
- LKV
CNA: What is it selective for?
Gram positives
PEA: What is it selective for?
Gram positives
HE: What is it selective for?
Gram negatives
CampyBA: What is it selective for?
Campylobacter species
SSA: What is it selective for?
Streptococcus species
TM: What is it selective for?
- Neisseria species
- Haemophilus species
LKV: What is it selective for?
anaerobes
Differential media
- allows growth to be distinguished
- supports desired class of microbes while inhibiting other microbes
- is selective media, with addition of distinguishing growth patterns or appearance
6 examples of differential media
- MAC
- EMB
- XLD
- SS
- CIN
- MSA
MAC
- MacConkey
- contains bile salts and crystal violet
- selective for GNR
- further differentiates between lactose fermenter (grow pink) and non-fermenter (grow colorless)
EMB
differential media for Gram negatives
XLD
differential media for Gram negatives
SS
- differential media for Gram negatives
- aids in identifying Salmonella and Shigella species
CIN
differential media for Yersinia species
MSA
- differential media for S. aureus and other Staphylococcus species
#growth indicates Staphylococcus species
#yellow growth indicates S. aureus - high salt content
Enrichment media
- sometimes a broth
- non-selective
- encourages growth of microbes to enhance specimen
- also used to encourage growth of fastidious microbes
Fastidious
hard to grow
4 examples of enrichment media
- BHI
- CHOC
- GN broth
- Thio broth
BHI
- brain heart infusion
- enrichment media for fungal microbes
CHOC
- chocolate agar
- enrichment media that allows all to grow, including many fastidious
GN broth
- enrichment media that encourages Salmonella species and Shigella species
- also inhibits enteric species (normal flora of GI tract)
Thio broth
- thioglycolate broth
- enrichment media for all microbes
- usually used in addition to plates for most wounds, joints, etc.
About using broth as enrichment media
- broth is good environment for things to grow, but takes more time
- cannot isolate specimen directly from broth
- must transfer it to solid media
Transport media
- used to maintain the numbers and viability of microbes
- not designed to increase their growth (just maintain it)
- often used for:
#transport to lab from off-campus site
#transport to reference lab
Specialized media
- used when previous categories will not allow target microbe to grow
- can be needed when NF is so abundant that it must be screened to find pathogen
Example of specialized media
- MTM
- modified Thayer-Martin
- used to grow Neisseria gonorrhoeae
