A gram negative rod from urine ferments lactose on MacConkey agar and is indole positive. Which organism is most likely?
1Klebsiella pneumoniae
2Proteus mirabilis
3Pseudomonas aeruginosa
4Escherichia coli✓ 정답
해설
Enteric gram-negative rods are first divided by lactose fermentation. Lactose fermentation combined with a positive indole reaction is characteristic of Escherichia coli. Klebsiella pneumoniae ferments lactose but is indole negative, and Proteus and Pseudomonas do not ferment lactose.