The presence of which bacteria indicates that there is a significant chance of fecal contamination?

The presence of coliforms in water is a strong indicator of fecal contamination. Coliforms are a group of bacteria commonly found in the intestines of warm-blooded animals and humans. Their presence in water suggests that pathogens potentially harmful to human health could also be present, as the same source that introduces coliforms may also introduce other harmful microorganisms.

Testing for coliforms is a standard method in water quality assessment because these bacteria are relatively easy to detect, and they serve as a general indication of water safety. If coliform bacteria are found, it usually prompts further testing to identify the specific pathogens that may be present, as coliforms can signal not only fecal contamination but also the possible presence of a wide range of harmful bacteria, viruses, and parasites.

In contrast, while the other bacteria mentioned, such as Salmonella, Streptococcus, and Clostridium, can also indicate contamination, they do not specifically indicate fecal contamination as clearly as coliforms do. For instance, Salmonella is often associated with foodborne illness and may come from various sources, while Clostridium can be found in soil and the environment. Streptococcus species can indicate fecal contamination (particularly enterococci), but they