identifying bacteria

Question 1

what are cocci bacteria

Answer 1

• round / spherical
• Appear in groups / chains
• Common in skin and respiratory infections

Question 2

what are bacilli bacteria

Answer 2

• rod shaped
• Straight / slightly curved
• Found in soil, gut, and infection sites

Question 3

what are Spirilla bacteria

Answer 3

• spiral or corkscrew shaped
• May have flagella
• Less common but include some waterborne and zoonotic pathogens

Question 4

what is Colony morphology

Answer 4

how bacteria look when they grow on an agar plate, the visible characteristics help identify the type of bacteria without using a microscope, each species tends to produce colonies with distinct appearances

Question 5

what are the key features to observe when identifying bacteria

Answer 5

• size
• shape
• colour
• texture
• elevation

Question 6

what colours may bacteria be

Answer 6

white, yellow, cream, red or green, some bacteria produce colourful pigments

Question 7

what does it tell us if bacteria have grown on an agar plate

Answer 7

they are able to survive the selective agents in the media.​

Question 8

what does it tell us if bacteria have not grown on an agar plate

Answer 8

bacteria may be inhibited by the selective substances.

Question 9

what does it tell us if bacteria have produced a certain colour on an agar plate

Answer 9

what metabolic activity such as fermentation is taking place

Question 10

why might agar sometimes change colour around certain colonies

Answer 10

chemical reactions such as change in ph level

Question 11

what do clear zones indicate on blood agar

Answer 11

beta hemolysis
complete destruction of red blood cells.

Question 12

what do greenish zones indicate on blood agar

Answer 12

alpha hemolysis
indicate partial breakdown.

Question 13

what do no changes indicate on blood agar

Answer 13

gamma hemolysis
no hemolysis.

Question 14

what does it mean if macconkey agar has pink colonies

Answer 14

there are lactose fermenters

Question 15

what does it mean if macconkey agar has colourless colonies

Answer 15

non-fermenters

Question 16

what does it mean if Mannitol Salt Agar has a yellow zone

Answer 16

there are mannitol fermenters

Question 17

what does it mean if Mannitol Salt Agar has No colour change

Answer 17

non-fermenters