title: Membrane filter method for enumerating Escherichia coli.
abstract: A membrane filter procedure for enumerating Escherichia coli was developed and evaluated. The method quantifies E. coli within 24 h without requiring subculture and identification of isolates. It incorporates a primary selective-differential medium for gram-negative, lactose-fermenting bacteria; resuscitation of weakened organisms by incubation for 2 h at 35 degrees C before incubation at 44.5 degrees C for 18 to 22 h; and an in situ urease test to differentiate E. coli from other thermotolerant, lactose-positive organisms. The recovery of E. coli from marine, estuarine, and freshwater samples exceeded 90%. Of the presumptively positive colonies, 91% were verified as E. coli. Less than 1% of all of the verified E. coli colonies failed to react typically.
mesh_terms: D001431:Bacteriological Techniques; D003470:Culture Media; D004926:Escherichia coli / Q000302:isolation & purification*; D005374:Filtration; D005618:Fresh Water; D012623:Seawater; D013696:Temperature; D014871:Water Microbiology
chemical_list: D003470:Culture Media