Indicator bacteria characteristics include which of the following?

Indicator bacteria characteristics include which of the following?

• A. Gram-negative, non-spore forming, facultative, rod-shaped, lactose fermenting
• B. Gram-positive, spore-forming, obligate anaerobes
• C. Gram-negative, spore-forming, obligate aerobes
• D. Gram-positive, non-spore forming, facultative, rod-shaped, lactose fermenting

Answer: (A)

Indicator bacteria used to gauge fecal contamination are typically Gram-negative, non-spore forming, facultative anaerobes, rod-shaped, and lactose fermenters. This combination matches coliforms like E. coli, which grow in the gut and on lactose-containing media, producing acid (and sometimes gas) from lactose fermentation. That makes this description the best fit for common fecal indicators. The other descriptions involve Gram-positive organisms, spore formers, or anaerobic/aerobic groupings that aren’t used as standard fecal indicators in routine testing.

Indicator bacteria used to gauge fecal contamination are typically Gram-negative, non-spore forming, facultative anaerobes, rod-shaped, and lactose fermenters. This combination matches coliforms like E. coli, which grow in the gut and on lactose-containing media, producing acid (and sometimes gas) from lactose fermentation. That makes this description the best fit for common fecal indicators. The other descriptions involve Gram-positive organisms, spore formers, or anaerobic/aerobic groupings that aren’t used as standard fecal indicators in routine testing.