Lesson 3: Methods of Studying Bacteria Flashcards
Bacteria that causes “Strep Throat”
Streptococcus pyogenes
A gram stain of “Sputum” showing numerous WBCs and gram-positive encapsulated diplococci is highly suggestive of?
Streptococcus pneumoniae
Gram-negative diplococci clustered in WBCs in a sample of “urethral secretion” from a male is considered diagnostic for?
“ONLY Gram-negative diplococcus found inhabiting the normal sterile urethra of a male”
Neisseria gonorrhoeae (causative agent of gonorrhea)
It is the most common causative organism of urinary tract infection which forms “PINK” colonies on MacConkey agar because of its ability to ferment lactose
E. coli
Most widely used stain in the laboratory
Gram-stain
“Red colony” when incubated at 22C owing to the production of pigments
Serratia marcescens
Gram stains pink to dark red
Gram-negative
A nutritionally rich medium containing red blood cells
Blood agar
Gram stains purple to blue
Gram-positive
Blood agar is a “DIFFERENTIAL MEDIUM” that enables to detect the characteristic B-hemolytic colonies of?
Streptococcus pyogenes
A stain used in mycobacterium tuberculosis
Acid-fast stain
The ability to fix nitrogen under aerobic condition is an identifying characteristic of these bacteria
Azitobacter
It is an identifying marker of the bacteria which is attached to the polysaccharide. It is an indirect identification of bacteria, because it is specific to that particular bacteria
Antigen
Soluble pigment which discolors the growth medium
Distinct “Fruity Odor”
Pseudomonas aeruginosa
Identify the Agar:
Contains:
1. BILE SALTS (inhibits the growth of most non-intestinal organisms)
2. Lactose with a pH indicator (differentiates lactose fermenting organisms)
MacConkey agar
Urine samples collected from a patient suspected of having a urinary tract infection is plated onto a __________ , which is both a “SELECTIVE AND DIFFERENTIAL” agar
MacConkey agar
ANIMAL INOCULATION
Rickettsia spp. requires?
Living cells
ANIMAL INOCULATION
It can be maintained in the laboratory in testicular chancre of rabbits
Treponema pallidum
ANIMAL INOCULATION
McCoy cells
HeLa 229
Buffalo Green Monkey Kidney Cells
Cycloheximide-treated McCoy Cells
These are found in what spp?
Chlamydia spp.
E. coli has the ability to ferment what?
Lactose
ANIMAL INOCULATION
Mycobacterium leprae are found in? (2)
Footpad of Mice (low temperature)(30C of footpads)
Armadillo (animals with low body temp)
Hybridization methods are based on the ability of two nucleic acid strands that have complementary base sequence to specifically bond with each other and form a double-stranded molecule (hybrid)
Nucleic acid hybridization methods
Require that one nucleic acid strand is from the known organism while the other is derived from the organism to be identified or detected
Hybridization assays
The result of hybridization is expressed as?
Percent hybridization
Percent similarity
Percent relatedness
Three categories of Amplification Techniques
Target amplification
Signal amplification
Probe amplification
These systems amplify the target to large numbers
Target amplification
These techniques are used to increase the “SENSITIVITY” of the probe-based assays
Signal Amplification
This method involves the determination of nucleotide sequence in the given DNA molecule
Sequencing
Two popular methods for sequencing DNA
Chemical Cleavage Method
Chain Terminator Method
