Final answer:
Escherichia coli (E. coli) is the pathogenic bacterial organism commonly monitored in water to assess microbiological safety, as it can indicate fecal contamination and the potential presence of other dangerous pathogens.
Step-by-step explanation:
The pathogenic bacterial organism monitored in water to determine microbiological safety is Escherichia coli (E. coli). This gram-negative rod is a common member of the normal microbiota of the colon, but some strains can be pathogenic, causing dangerous diarrheal disease. These strains possess additional virulence factors that promote colonization or produce toxins. To ensure water safety, testing for E. coli is performed because its presence indicates possible contamination with other harmful pathogens. The presence of E. coli in water can be an indicator of the presence of other dangerous bacteria and viruses, such as Salmonella and norovirus. Therefore, monitoring E. coli levels in water is crucial for assessing its microbiological safety.
Other pathogenic bacteria that may be present in water and are of concern include Clostridium botulinum, which produces a toxin causing botulism; Bacillus cereus, which can cause food poisoning; and Pseudomonas aeruginosa, known for hospital-acquired infections. However, E. coli is often used as an indicator organism because certain strains can directly indicate fecal contamination and the potential presence of other pathogens.