Suppose you were interested in the effect of breastfeeding versus formula feeding on the composition of gut flora in newborns. As part of your experiment, stool samples from healthy babies in the study get plated on various agar media. You notice that greater numbers of colonies are recovered when samples are plated on blood agar compared to Luria Bertani (LB) agar. After some diligent subculturing, you isolate several bacterial species capable of slow growth on the blood but not on the LB agar. You correctly surmise that these organisms
Choose one:
A. are opportunistic blood pathogens.
B. should be classified as beta-hemolytic.
C. have extensive and complex nutritional requirements not met by LB agar.
D. grow because the blood agar suppresses the growth of faster-growing bacteria.
E. are Gram-positive and, thus, inhibited by the ingredients in LB agar.