BACTERIOLOGY SIMLAB Flashcards
most commonly used stain in the clinical microbiology laboatory
Gram Stain
Procedure of Gram Stain
Crystal Violet - 60 secs
Gram’s Iodine - 60 secs
Acetone Alcohol - 30 secs
Safranin - 60 secs
Color of gram-positive bacteria
violet/blue
Color of gram-negative bacteria
red/pink
What are gram-positive cocci
Staphylococcus
Streptococcus
Lactococcus
Viridans streptococcus
Enterococcus
What are gram-negative cocci
Neisseria
Veillonella
Moraxella
Gram-positive bacilli
Mycobacterium
Corynebacterium
Clostridium
Bacillus
Erysipelothrix
Lactobacilli
Listeria
Gram-negative bacilli
Escherichia
Klebsiella
Enterobacter
Serratia
Hafnia
Yersinia
Pseudomonas
Proteus
Morganella
Shigella
Salmonella
used to differentiate acid-fast organisms such as mycobacteria by staining their mycolic acid
Acid Fast Stain
Procedure of Acid Fast Stain
Carbolfuchsin - 10-15 mins
Heat
Acid Alcohol - 30 seconds
Methylene Blue - 60 seconds
Color of Acid Fast Bacteria (AFB)
Red/Pink
Color of Non - Acid Fast Bacteria
Blue/Violet
Give an example of Acid Fast Organism
Mycobacterium
Isospora
Cryptosporidium
Nocardia
Give an example of Non-Acid Fast Organism
Chlamydia
Rickettsia
Ureaplasma
Mycoplasma
Spirochetes
Bartlett’s Criteria
> 25 PMNs and <10 Epithelial Cells
Stain for spore-forming bacteria
Schaeffer-Fulton
what is the interpretation of +n
1-9 AFB seen in 100 OIF
what is the interpretation of +1
10-99 AFB seen in 100 OIF
what is the interpretation of +2
1-10 AFB/OIF in at least 50 fields
what is the interpretation of +3
> 10 AFB/OIF in at least 20 fields
Bacteria that are Rapid Lactose Fermenters (RLF)
Escherichia
Klebsiella
Enterobacter
Bacteria that are Late Lactose Fermenters (LLF)
Serratia
Hafnia
Yersinia
Bacteria that are Non-Lactose Fermenters (NLF)
Pseudomonas
Proteus
Morganella
Shigella
Salmonella
what is the interpretation of O
No AFB seen in 300 oil immersion field (OIF)
IMViC Reaction of Escherichia
+ + - -
IMViC Reaction of Klebsiella
- +
IMViC Reaction of Enterobacter
- +
What does the PYR test detect?
L-pyrrolidonyl arylamidase.
What is the function of endospores in bacteria?
Structure resistant to heat, cold, drying, and
chemical agents; contains calcium dipicolinic acid.
What is the indicator for autoclave sterilization?
Bacillus stearothermophilus
What is the indicator for oven sterilization?
Bacillus subtilis var niger
Name a group of bacteria that are non-motile.
Shigella
Klebsiella
Yersinia pestis
Which bacteria are routinely screened for in a stool
specimen?
Salmonella
Shigella
Campylobacter
What is the purpose of the Acid Fast Stain?
To identify organisms with mycolic acid /
hydroxymethoxy acid in their cell walls
What is the purpose of enrichment media?
For enhanced growth of organisms.
What is the purpose of enriched media?
For fastidious organisms
Name an inhibitor for gram-positive organisms.
Crystal violet and sodium desoxycholate.
Name an inhibitor for gram-negative organisms.
Sodium azide, potassium tellurite
What is the purpose of the optochin test?
Identification of Streptococcus pneumoniae.
What is the indicator/reagent used in the coagulase
test?
Rabbit plasma.
What does the DNAse test detect?
Deoxyribonuclease activity.
What does the CAMP test differentiate?
Group B from Group A Streptococcus.
Detects Ability to split indole from
tryptophan due to the presence of
tryptophanase.
Indole Test
What is an indole test reagent?
Kovac’s Reagent: P-dimethylamino benzaldehyde
Detects acid Ph which indicates glucose
fermentation
Methyl Red Test
What is Vogues-Proskauer
Test Principle
Detects production of acetylmethyl
carbinol (acetoin)
What is Vogues-Proskauer
Test Reagent?
Alpha-naphthol
40% KOH (Barrit’s reagent)
What is the Citrate Test Principle?
To determine if an organism can utilized citrate as the sole carbon source
What is the Urease Test Principle?
To determine if an organism can hydrolyze of urea
What are the Indole-positive bacteria?
PECK ME Pro Pls
Providencia
Edwardsiella
Citrobacter
Klebsiella oxytoca
Morganella
Escherichia
Proteus
Plesiomonas
What are the Vogues-Proskauer-positive bacteria?
KESHa
Klebsiella pneumoniae
Enterobacter
Serratia
Hafnia
S.aureus
What are the Citrate-positive bacteria?
PECKS
Pseudomonas
Enterobacter
Citrobacter
Klebsiella
Serratia Marcescens
Used for presumptive identification of Gram-negative enteric bacteria used to test a microorganism’s ability to
ferment sugars and produce hydrogen sulfide.
Triple Sugar Iron Agar
A/A, H2S -, Gas +
Escherichia
Klebsiella
Enterobacter
K/A, w/ Gas , H2S +
Salmonella
Proteus
Arizonae
Citrobacter
Edwardsiella tarda
K/A, w/ Gas , H2S -
Providencia
Morganella
Shigella
K/K, H2S -
Pseudomonas
Burkholderia
ONPG Test Principle
To determine the ability of an organism
to produce beta-galactosidase
Beta galactosidase converts ONPG to
ortho-nitrophenol