美国食品药品局细菌分析手册（BAM）第4章：大肠杆菌和大肠菌群的计数（2020年10月版）BAM Chapter 4: Enumeration of Escherichia coli and the Coliform Bacteria

Escherichia coli, originally known as Bacterium coli commune, was identified in 1885 by the German pediatrician, Theodor Escherich (14, 29). E. coli is widely distributed in the intestine of humans and warm-blooded animals and is the predominant facultative anaerobe in the bowel and part of the essential intestinal flora that maintains the physiology of the healthy host (9, 29). E. coli is a member of the family Enterobacteriaceae (15), which includes many genera, including known pathogens such as Salmonella, Shigella, and Yersinia. Although most strains of E. coli are not regarded as pathogens, they can be opportunistic pathogens that cause infections in immunocompromised hosts. There are also pathogenic strains of E. coli that when ingested, causes gastrointestinal illness in healthy humans (see Chap. 4A).
In 1892, Shardinger proposed the use of E. coli as an indicator of fecal contamination. This was based on the premise that E. coli is abundant in human and animal feces and not usually found in other niches. Furthermore, since E. coli could be easily detected by its ability to ferment glucose (later changed to lactose), it was easier to isolate than known gastrointestinal pathogens. Hence, the presence of E. coli in food or water became accepted as indicative of recent fecal contamination and the possible presence of frank pathogens. Although the concept of using E. coli as an indirect indicator of health risk was sound, it was complicated in practice, due to the presence of other enteric bacteria like Citrobacter, Klebsiella and Enterobacter that can also ferment lactose and are similar to E. coli in phenotypic characteristics, so that they are not easily distinguished. As a result, the term "coliform" was coined to describe this group of enteric bacteria. Coliform is not a taxonomic classification but rather a working definition used to describe a group of Gram-negative, facultative anaerobic rod-shaped bacteria that ferments lactose to produce acid and gas within 48 h at 35°C. In 1914, the U.S. Public Health Service adopted the enumeration of coliforms as a more convenient standard of sanitary significance.

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