Table 1. Interpretation guide.

Most commonly encountered combinations of results and their interpretation.

Procedure Subject	A	B		C	D	Interpretation / Troubleshooting
	Mesa formation	First patch test	Second patch test	Supernatantassay	Immunity assay
Phage/host 1	-	N/A	N/A	N/A	N/A	Phage unable to lysogenize host (?)Repeat A with lower phage titers and/or a longer incubation time
Phage/host 2	+	-*	N/A	N/A	N/A	Phage unable to lysogenize host
Colony 1	N/A	+	-	-	-	Phage carried-over from the streak plate, no lysogen production
Colony 2	N/A	+	+	+	+	Successful lysogen production
Colony 3	N/A	-	-	-	+	Phage resistance due to other mechanisms
Colony 4	N/A	+	-	-	+	False positive on the first patch test, phage resistance due to other mechanisms

* At least 20 colonies screened, 10 from each of 2 different mesas. +: positive test. -: negative test.