Which bacteria type is not analogous to a water quality indicator?

Staphylococcus aureus is not considered an analog to a water quality indicator. In the assessment of water quality, indicator organisms are selected based on their relationship to fecal contamination and the potential presence of pathogens. Fecal coliform bacteria and E. coli are specifically chosen because they originate from fecal material and indicate the possible presence of harmful microorganisms. Coliform bacteria, as a broader category, also includes organisms like fecal coliforms, reinforcing their role in indicating water quality issues.

Staphylococcus aureus, while it can be pathogenic, does not specifically signal fecal contamination or indicate the presence of waterborne pathogens in the same way that the other types mentioned do. Therefore, it is not utilized as a water quality indicator despite having significance in other contexts, such as food safety and human health.