Gram Film Interpretation Flashcards
Gram negative organisms stain?
Pink / red
Gram positive organisms stain?
Purple
Describe how gram stain is done
Cocci can be described what ways?
Diplococci (growing in pairs)
Growing in a chain
Growing in a cluster like grapes
What are these two shapes?
What are these shapes?
What are these shapes?
What are examples of gram positive cocci in clusters?
Staphylococcus e.g. staph aureus (can cause cellulitis, endocarditis, osteomyelitis, iatrogenic from cannula or central line insertion)
Others: staph epidermis (can cause endocarditis in prosthetic heart valves)
What are examples of gram positive diplococci?
Strep pneumoniae (disease presentation: pneumonia, meningitis, otitis media)
Others: enterococci (enterococcus faecium, enterococcus faecalis - can cause UTIs, intra abdominal infections)
What are examples of gram positive cocci in chains?
Strep pyogenes (aka group A strep) - disease presentation: tonsillitis, scarlet fever, rheumatic fever, cellulitis
Others: strep agalactiae (aka group B strep) - causes neonatal sepsis
Alpha haemolytic produces what tinge?
Greenish tinge on agar
What organisms are in alpha haemolysis?
Strep pneumoniae
Strep viridans
What organism is in gamma haemolysis?
Staph epidermidis
Gamma haemolysis causes what tinge?
None - no haemolysis
Beta haemolysis can be further divided using what system?
Lancefield grouping
How do you do lance field grouping?
Give examples of Groups A, B, C/G and D on lance field grouping
What are examples of gram positive bacilli?
Clostridium perfringens (gas gangrene, cholecystitis, gastroenteritis)
Others: c diff (gastroenteritis), C. tetani (Tetanus), Listeria monocytogenes (meningitis, gastroenteritis, neonatal sepsis)
What are examples of gram negative diplococci?
Neisseria meningitidis (meningitis)
Others: moraxella catarrhalis (causes pneumonia, otitis media, sinusitis)
What are examples of gram negative coccobacilli?
Haemophilus influenza (pneumonia, meningitis)
Others: bordetella pertussis (whooping cough), acinetobacter (causes Hospital acquired infections)
What are examples of gram negative bacilli?
E. coli
Proteus
Klebsiella
Disease presentation: UTI, pyelonephritis, cholecystitis, cholangitis, intra abdominal infections
What are examples of vibrios?
Vibrio cholera (cholera)
Others: vibrio vulnificus (cellulitis, diarrhoea); vibrio parahaemolyticus (gastroenteritis)
What are examples of spirochetes?
Treponema pallidum (syphilis)
Others: borellia burgdorferi (Lyme disease)
What are examples of bacteria that don’t gram stain?
Mycobacteria (mycobacteria tuberculosis) - causes TB
Others: chlamydia, mycoplasma
