TABLE 1.

Summary of Fast Phage modifications compared to Method 1601

Method 1601Fast Phage modification
Preculture host E. coli strain (CN-13 for somatic coliphages and Famp for male-specific coliphages) overnight. Transfer to TSB and bring to optical density at 520 nm of 0.1 to 0.5. IcePredispensed dried medium components in dissolvable film. Formulation proprietary for rapid amplification
Prepare 10× TSB, MgCl2, antibiotic solutions in advance and filter autoclavePredispensed dried medium components in dissolvable film. Formulation proprietary for rapid amplification
Add prepared solutions and E. coli to water sample in precise sequence of additions and temperaturesAdd STEP-1 medium pouch to water sample in test vessel. Gently swirl to dissolve contents for ∼10 min. Add E. coli tablet (same host as Method 1601). Swirl to dissolve tablet
Incubate overnight at 36 ± 1°C in air incubatorIncubate for 30 min in water bath at 38 ± 1°C. Incubate for 4 h 30 min in air incubator at 39 ± 1°C
Use precultured exponential-phase E. coli to make spot plates. Prepare TSA, autoclave, and add preprepared and sterile-filtered antibiotic solution after temperingUse E. coli tablet as TSB inoculum. Add sterile water to supplied freeze-dried antibiotic (nalidixic acid for somatic coliphages or ampicillin-streptomycin for F+ coliphages) to make solution. Prepare TSA, autoclave, and add antibiotic solution after tempering
Transfer 10 μl of enrichment culture (24 h) to spot plate. Incubate overnight at 36 ± 1°C in air incubator. Total elapsed time, approx 60 hTransfer 10 μl of STEP-1 enrichment culture (5 h) to spot plate. Incubate overnight at 39 ± 1°C in air incubator. Total elapsed time, 16 to 24 h
Fast prediction is not part of the methodTransfer STEP-1 enrichment culture (1 ml for F+ or 10 ml for somatic coliphages) to 100 ml indicator medium STEP-2. Incubate up to 3 h for fluorescence-positive results to predict positive spot result. Total elapsed time, 5.5 to 8 h