Ch. 7 - Traditional Cultivation and Identification Flashcards
2 bacteria that cannot be developed in vitro
- Treponema pallidum
- Mycobacterium leprae
process of growing microorganisms in culture
Cultivation
bacteria with complex needs and exceptional media components
fastidious
Bacteria that has relatively basic and straightforward needs
Nonfastidious
Indicates bacterial growth in broth media
Turbidity
Amount of bacteria needed for turbidity to be detected by the naked eye
10^6 bacteria per milliliter
Type of broth media where the location of growth indicates the type of bacteria present based on oxygen requirements
Thioglycollate broth
Bacteria that grow at the bottom of Thioglycollate broth
Strict anaerobes
Bacteria that grow near the surface of Thioglycollate broth
Aerobic bacteria
Type of bacteria that will grow throughout the Thioglycollate broth media
- Facultative anaerobes
- Aerotolerant organisms
Most common solidifying agent
Agarose
The formed stable solid gel in solid medium
Agar
Petri dish containing agar
Agar plate
The bacterial population is considered to be derived from a single bacterial cell
Pure colony
Media that contains specific nutrients required for the growth of particular bacterial pathogens
Used to enhance growth of a particular bacterial pathogen by providing specific nutrients for the organism’s growth
Enrichment media
Enrichment broth for isolation of anaerobes
Thioglycollate
Enrichment media for Group B streptococci
LIM broth
Enrichment media for enteric gram-negative organisms
Gram-negative (GN) broth
Media that contains nutrients that support growth of most nonfastidious organisms without giving any organism a growth advantage
Nutritive media/Supportive media
Nutritive media for bacteria
- Tryptic soy agar
- Nutrient agar plates
Nutrient media for fungi
Sabouraud’s dextrose agar
Media that contains one or more inhibitory agents (dyes, bile salts, alcohols, acids and antibodies)
Selective media
Selective media for gram-positive cocci; inhibits aerobic and facultatively anaerobic gram-negative rods
Phenylethyl alcohol (PEA) agar
Media that allows colonies of one bacterial species or type to exhibit certain metabolic or culture characteristics that can be used to distinguish it from other growing bacteria
Differential media
Differential media to differentiate gram-negative bacteria that can and cannot ferment the sugar lactose
MacConkey agar
Most commonly used nutritive medium because it allows many organisms to grow
Also differential because appearance of colonies produced by certain bacterial species is readily distinguishable
Sheep blood agar
Agar for culturing a patient’s blood for bacteria
Brain-Heart Infusion (BHI) agar
Agar for cultivation of Haemophilus spp. & Neisseria gonorrhoeae
Hemoglobin, hemin and nicotinamide adenine dinucleotide (NAD) are released into the agar
Chocolate agar
Agar that allows gram-positive bacterial growth
Can be used to differentiate bacterial colonies on the hemolytic reactions they produce
Contains 2 antibiotics
Columbia CNA agar with blood
Antibiotic that disrupts cell membranes of gram-negative organisms
Colistin
Antibiotic that blocks DNA replication in susceptible organisms
Nalidixic acid
Agar for the selective growth of gastrointestinal pathogens (Salmonella spp. & Shigella spp.)
Contains mannitol
Gram-negative (GN) broth
Primary source of carbon in media. Favored energy source for many enteric pathogens.
Mannitol
Agar for growth of Salmonella spp. and Shigella spp.
Differential for lactose and non-lactose fermenting gram-negative bacilli: non-lactose fermenters maintain blue-green color of the agar
Contains ferric ammonium citrate for detection of H2S (black ppt) produced by Salmonella spp.
Hektoen Enteric (HE) agar
Color of Salmonella spp. and Shigella spp. in Hektoen Enteric agar
Blue-green (original color of the medium)
Agar for gram-negative bacilli
Differentiates lactose and non-lactose fermenters: non-lactose fermenters remain colorless(Shigella spp.)
MacConkey agar
Agar for gram-positive cocci
Phenylethyl Alcohol (PEA) agar
Agar that supports growth for all but the most fastidious clinically significant bacteria
Sheep blood agar
Complete clearing of the RBCs around the bacterial colony
Beta hemolysis
Partial lysis of RBCs to produce a greenish discoloration around the colony
Alpha hemolysis
Enrichment and selective agar for the isolation Neisseria gonorrhoeae & Neisseria meningitidis
Has 3 antibiotics: Colistin, Vancomycin, Nystatin
Modified Thayer-Martin (MTM) agar
Antibiotic that inhibits gram-positive bacteria
Vancomycin
Antibiotic that inhibits yeast
Nystatin
Antibiotic that may be added to MTM agar that inhibits Proteus spp. which may swarm over the agar surface and mask detection of individual colonies of the 2 Neiserria spp.
Trimethoprim
A modification of MTM agar where ansamycin substitutes nystatin and there is a higher concentration of vancomycin
Martin-Lewis agar
Enrichment broth most frequently used in diagnostic bacteriology
Thioglycollate broth
Agar that is selective and differential for Shigella spp. and Salmonella spp.
Salmonella spp. often exhibits a black center due to production of H2S
Xylose Lysine Desoxycholate (XLD) agar
3 bacterial pathogens that require living cells for cultivation
- Chlamydiae
- Rickettsiae
- Ricketstiae-like organism
Type of organisms that grow best with higher CO2 concentration
Capnophilic
Primary lab devices used to provide the environmental requirements for cultivating microorganisms
Incubators
Optimum temperature for incubation
35-37 C
Optimal amount of CO2 for incubation
3-5% CO2
Optimum pH level for incubation
6.5 - 7.5
Temperature at which Campylobacter jejuni is able to grow
42 C
Temperatures that enable Listeria monocytogenes and Yersinia enterocolitica to grow
4 - 43 C
Type of organisms that require only low levels of oxygen
Microaerophilic/Microaerobic
