Introduction to Culturing Bacteria Flashcards
single-celled living
organisms
BACTERIA
are groups of microbes living in and on your body.
resident flora/microbiome
functions of resident flora (3)
absorbing nutrients;
breaking down food;
preventing the growth of harmful bacteria.
Foods like sauerkraut, soy sauce, sourdough, and cheese are fermented by ___
lactic acid bacteria
lactic acid bacteria examples (2)
Lactobacillaceae; Streptococcaceae families
taken to maintain gut health, rely on a combination of live beneficial bacteria and yeast that already live in your body
Probiotics
common probiotics (3)
Lactobacillus;
Bifidobacterium;
Saccharomyces boulardii
baker’s yeast
Saccharomyces cerevisiae.
4 microbes that have beneficial functions
lactobacillus
penecillium
Saccharomyces cerevisiae
Fusarium strain flavolapis
probiotics rely on good bacteria, like this one, to maintain gut health and keep your body running optimally
lactobacillus
Your bread rises and your beer is brewed thanks to this fungal species; also the same microbe used in nutritional yeast, a nutrient rich savory vegan supplement
saccharomyces cerevisiae
penicillin comes from this type of fungus with antibacterial properties that led to the first mass-produced antibiotic
Penicillium
with origins in yellowstone, Nature’s Fynd ferments this mcrobe to make Fy, our nutritional fungi protein.
Fusarium strain flavolapis
are microorganisms that can cause disease
Pathogens
Harmful bacteria examples (3)
Streptococcus:
Staphylococcus:
Escherichia coli
cause strep throat
Streptococcus:
cause staph infections
Staphylococcus:
Staphylococcus, Streptococcus, Escherichia coli are the most common germs responsible for ___ or blood poisoning
septicemia
Bacteria in blood can spread and lead to ___, a systemic overreaction to widespread infection in your body
sepsis
Other examples of pathogenic bacteria (3)
Aerococcus urinae
Chlamydia trachomatis
Bordetella pertussis
Bacteria in urine that cause urinary tract infections.
Aerococcus urinae
Bacteria that cause a sexually transmitted infection (STI) called chlamydia.
Chlamydia trachomatis
Bacteria that cause whooping cough.
Bordetella pertussis
pure culture by ___
RObert Koch
method that allows the multiplication of bacterial cells in or on a culture medium under controlled laboratory conditions.
bacterial culture
enables genome sequencing of these strains
Bacterial culture
first step in establishing recommendations for effective treatment.
Bacterial culture
enables the study of the antibiotic susceptibility of bacteria
Bacterial culture
enables manipulation and transformation by adding or deleting genes to analyze the cause of virulence
Bacterial culture
Most bacteria can grow to some extent in the presence of oxygen, known as
aerobic culture.
Species found in atmospheric conditions, such as on the skin surface or in the upper respiratory tract, will typically grow well in the presence of oxygen.
aerobic culture.
Species that are naturally found in low oxygen environments, such as in deep wounds or abscesses or the deep ocean, will typically grow best in the absence of oxygen
anaerobic culture.
some cannot grow in the presence of oxygen at all, and these are called
obligate anaerobes
example of obligate anaerobes (4)
Fusobacterium
Bacteroides
Gram negative Pseudomonas aeruginosa
Mycobacterium tuberculosis
bacteria that can grow in either aerobic or anerobic conditions, switching from aerobic respiration to fermentation or anaerobic respiration if oxygen is absent, are called
facultative anaerobes
example pf facultative anaerobes (4)
Gram positive staphylococci
E. coli
Salmonella
Listeria spp
The indications for culture are: (7)
• To isolate bacteria in pure cultures.
• To demonstrate their properties.
• To obtain sufficient growth for the preparation of antigens and for other tests.
• For bacteriophage & bacteriocin susceptibility.
• To determine sensitivity to antibiotics.
• To estimate viable counts.
• Maintain stock cultures.
CLASSIFICATIONS OF MEDIA (4)
Complete media
Minimal
Defined
Undefined
CLASSIFICATIONS OF MEDIA:
can be helpful when trying to bulk up a pure culture and get the bacterial cells in good condition
Complete media
CLASSIFICATIONS OF MEDIA:
supply only the bare necessities for survival and can be useful in manipulating which pathways are turned on in the bacterium.
Minimal media
CLASSIFICATIONS OF MEDIA:
all the ingredients are known
Defined media
CLASSIFICATIONS OF MEDIA:
tend to contain complex mixtures of nutrients and chemical species in unknown proportions, such as yeast extract.
Undefined media
is simply water and nutrients that support microbial growth.
culture medium
3 primary categories of culture media
nutritive
selective
differential
Media that support the growth of many different microorganisms
without distinguishing genera or species.
nutritive media
several different types of bacteria to grow, but also contain compounds that allow microbial genera.
differential
-organisms interact with the added compounds (e.g., blood, sugars)
differential
allows for the rapid identification of organisms of interest, which is especially important for heavily mixed cultures, such as stool.
Differential
used to select for the growth of a particular “selected” microorganism.
SELECTIVE
other chemicals can be added to media to create a selective environment.
SELECTIVE
example of selctive media
NaCl media selects for halophiles (salt lovers) versus non-halophiles.
Culture in liquid media, also known as a ___, gives the bacteria present easy access to the available nutrients compared to static bacterial colonies.
broth culture
dilute out waste products as they are formed, distributing them through the culture
Liquid media
Use ___ when aiming to bulk up your culture, e.g., when using bacteria to produce a desirable compound, in food production or to extract DNA.
broth cultures
When looking to store bacterial strains long term, they may be grown up in ___.
___ is then added, which will prevent complete freezing and consequent lysis of the bacterial cells, permitting their storage at __
liquid media;
Glycerol; -80 °C
Adding agar to liquid media enables it to be set in petri dishes, as slopes or in plugs.
Nutrient agar
useful when you wish to select individual colonies from a mixed culture,
Solid media
convenient method for transporting strains from lab to lab without the danger of spillage of potentially infectious materials
Inoculation onto slopes or in stab cultures
Common problems with bacterial culture (5)
-Contamination
-Overgrowth of some species
-Antibiotic treatment prior to sampling
-Incorrect growth conditions
-Non-culturable and slow-growing organisms
are very slow growing and can take months to culture successfully, which is particularly problematic when trying to diagnose infections.
mycobacteria,
Applications of bacterial culture (6)
-Diagnose infection
-Genetic manipulation
-Epidemiological study
-Scale up to enable omics studies
-Develop vaccines and therapeutics
-Food and beverage production
Strains may also be stored down for future reference, for example for disease monitoring purposes.
Diagnose infection
to understand the basic biology, to attenuate it when creating vaccine strains, to overproduce proteins and to create a reference strain with a detectable marker to name just a few.
Genetic manipulation
how bacterial populations change over time – which can inform therapeutic, vaccine and diagnostic design and updates.
Epidemiological study
next-generation sequencing (NGS) is still performed on material from many bacterial cells and as such, the bacteria often need to be cultured prior to DNA or RNA extraction.
Scale up to enable omics studies
Food and beverage production example (2)
Lactobacillus and Bifidobacterium
