Medical Microbiology

LaboratoryDiagnosis 213

FractionatedInoculationofNutrientAgar

Fig.3. 33 Isolated colo-

niesareobtainedbymeans

offractionatedinoculation

ofnutrientagar.Thewire

loopmustbesterilizedbe-

tweeninoculations.

BloodAgarPlateFollowingFractionatedInoculationandIncubation

Fig.3. 34 Bloodagarisfre-

quentlyusedasauniversal

enrichmentmedium.Most

humanbacterialpathogens

growonit.Hereisapurecul-

tureofStaphylococcusaur-

eus.

EndoAgarFollowingFractionatedInoculationwithaMixedCulture

Fig.3. 35 Endo agar is a

combined selective/indica-

tormedium.Itallowsgrowth

ofEnterobacteriaceae,Pseu-

domonadaceae, and other

Gram-negativerodbacteria

butinhibitsthegrowthof

Gram-positivebacteriaand

Gram-negative cocci. The

red color of the colonies

andagarischaracteristicof

lactosebreakdown(=Escher-

ichiacoli);thelight-coloredcoloniesarelactose-negative(=Salmonellaenterica).

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Kayser, Medical Microbiology © 2005 Thieme