Which of the following organisms is commonly found in freshwater habitats and can infect humans?

• A. Staphylococcus aureus
• B. Naegleria fowleri
• C. Escherichia coli O157:H7
• D. Candida albicans

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the habitat and characteristics of each organism listed. Staphylococcus aureus is typically found on human skin and mucous membranes, not commonly in freshwater environments.
2. Step 2: Recognize that Escherichia coli O157:H7 is a pathogenic strain of E. coli usually associated with contaminated food and water but is not specifically known as a freshwater organism.
3. Step 3: Candida albicans is a fungal organism commonly found in human mucosal areas and is not associated with freshwater habitats.
4. Step 4: Identify Naegleria fowleri as a free-living amoeba that thrives in warm freshwater environments such as lakes and hot springs and is known to infect humans by entering through the nasal passages.
5. Step 5: Conclude that among the options, Naegleria fowleri is the organism commonly found in freshwater habitats and capable of infecting humans, causing a rare but serious brain infection.