Lab Flashcards
Examples of gram positive cocci in chains
Group A B C Streptococcus
Enterococcus
Gram positive cocci in pairs examples
Streptococcus pneumonia
Enterococcus (pairs or chain)
Gram positive in clusters examples
Staphylococcus- MRSA, MSSA
Corynebacteria
Gram positive rods
Clostridium
Bacillus
Listeria
Gram negative cocci examples
Neisseria (pairs diplodocus)
Gram negative rods example
Enterobacteriase (ecoli, klebsella)
Pseudomonas
What sample can stay at room tem
Csf
Teichoic acid and thick peptitoglycan layers are associated with
Gram positive bacteria
What fluorescent stain is added that binds to chitin in cell wall of fungus
Calcofluor white
What are the 3 ways bacteria transfer resistance
Transformation: dna from environment enter bacteria
Conjugation: direct contact between bacteria and plasmid exchange
Transduction: transferred to recipient cell from virus capable of infecting bacteria (bacteriophage)
What kind of growth media supports the growth of a wide variety of bacteria?
Nutrient agar. Examples include trypticase soy agar with sheep blood
Enrichment media
Contains special nutrients for the growth of fastidious(hard to grow) bacteria. Chocolate agar- growth of n.meningitis
Selective media
Contains chemical or antibiotics designed to inhibit growth of normal commensal bacteria. Bismuth sulfate agar, macconkey’s agar
Differential media
Stains colonies of specific organisms while inhibiting growth of others. Acetate agar used to differentiate between ecoli and shigella
Obligate aerobes
Require oxygen to grow
Faculatative anaerobes
Grows with or without Oxygen. Greater growth in the presence of oxygen
Obligate anaerobes
Only grows without oxygen- anaerobic growth
Test used to differentiate between streptococcus and staphylococcus
Catalase test. Staphylococcus positive
Test used to differentiate between staphylococcus aureus and other staphylococcus
Coagulase test. S.aureus positive
Kirby Bauer method
Disc diffusion- bacteria spread and paper discs with antibiotics placed. Zone of inhibition is measured to identify resistance
Specimen and collection transport rules
Specimens collected aseptically and placed in sterile container
Some may be placed directly in culture media (blood, genital cultures)
Special handling techniques needed for some specimens (anaerobic cultures)
Prompt delivery is essential
If delayed- some can be refrigerated (urine, stool, sputum) but others must be maintained at room temp (genital, eye, Csf)
Wet mounts must be
Fresh samples
What enterobacteriase species can ferment lactose?
Klebsella, serratia, enterobactor, e coli
