Question

10. Fill in the blanks in this diagram to make a key for these 3 bacteria: Escherichia coli, Enterobacter aerogenes and Staphylococcus aurvens. Growth on EMB No es Metallic green colonies Thick mucoid pink colonies Growth on Mannitol Salt Agar Genus: Gram stain: Genus: Gram stain: Yes with yellow zone around growth Genus: Gram stain: 11. How can one distinguish the 3 common urinary tract pathogens on the HardyCHROMTM UTI demo plate? 12. What is the value of making a Gram stain directly from a clinical specimen?

Answer 1

10.

11. tabulated below

PATHOGEN	IDENTIFICATION
Escherichia coli	rose to magenta colonies with dark pink centred colony
Enterococcus spp.	teal to torquoise colonies
Staphylococcus aureus	opaque,cream to white coloured colonies
Candida albicans	small, opaque,white moist colonies
Klebsiella	deep blue to dark indigo colonies
Pseudomonas spp.	colourless to light yellow-green colonies
Proteus vulgaris	blue-green colonies
Citrobacter spp.	dark blue colonies often with a rose halo in the surrounding media.

12. Making a gram stain directly from the clinical specimen helps in narrowing down the range for the infection causing pathogens by differentiating among the gram negative and gram positive organisms.

gram positive- Actinimycetes, Clostridium, Mycoplasma etc

gram negative- E.coli, E.aerogens, Enterobactor, Campylobactor etc