TABLE 1.

Effects of strain age and method of cyst production on A. polyphaga disinfection

Drug	Straina	Log killing (mean ± SEM)b
		6-Mg		Neff		Taurine		NNA
		4h	6h	4h	6h	4h	6h	4h	6h
PHMB (3 μg/ml)	Ros-91	4.0 ± 0.2	4.0 ± 0.2	1.7 ± 0.7	3.1 ± 0.2	0.4 ± 0.3	0.4 ± 0.3	2.6 ± 0.4	3.3 ± 0.2
	Ros-02	0.9 ± 0.4	3.4 ± 0.6	0.2 ± 0.1	0.3 ± 0.1	0.2 ± 0.1	0.2 ± 0.1	0.8 ± 0.1	1.2 ± 0.3
MAPD (20 μg /ml)	Ros-91	3.9 ± 0.1	3.9 ± 0.1	3.7 ± 0.1	3.7 ± 0.1	2.9 ± 0.4	3.8 ± 0.1	1.7 ± 0.2	2.8 ± 0.3
	Ros-02	3.9 ± 0.1	3.9 ± 0.1	2.1 ± 0.2	4.5 ± 0.1	1.8 ± 0.0	2.9 ± 0.3	1.7 ± 0.2	2.7 ± 0.2
MPS-1 (1 μg /ml)	Ros-91	3.6 ± 0.4	4.3 ± 0.1	2.8 ± 0.2	3.9 ± 0.6	2.8 ± 0.1	3.7 ± 0.4	1.6 ± 0.3	1.7 ± 0.3
	Ros-02	3.0 ± 0.4	3.8 ± 0.1	1.9 ± 0.5	3.4 ± 0.2	1.2 ± 0.3	1.5 ± 0.3	0.9 ± 0.2	1.7 ± 0.4
MPS-2 (1 μg /ml)	Ros-91	1.8 ± 0.4	3.7 ± 0.4 (2.9 ± 0.5)c	0.8 ± 0.1	1.0 ± 0.0 (1.4 ± 0.2)	2.4 ± 0.3	3.3 ± 0.4	0.4 ± 0.2	1.0 ± 0.2 (1.1 ± 0.3)
	Ros-02	1.7 ± 0.2	2.4 ± 0.1	1.2 ± 0.2	1.8 ± 0.3	1.1 ± 0.1	1.3 ± 0.0	0.2 ± 0.1	1.0 ± 0.1
CHLX (30 μg /ml)	Ros-91	0.8 ± 0.1	1.0 ± 0.3	1.7 ± 0.3	1.8 ± 0.3	0.5 ± 0.1	0.8 ± 0.2	0.8 ± 0.1	1.5 ± 0.5
	Ros-02	0.7 ± 0.2	1.2 ± 0.5	0.6 ± 0.4	1.1 ± 0.2	0.1 ± 0.1	0.4 ± 0.1	0.2 ± 0.3	0.2 ± 0.3
Peroxide (3%)	Ros-91	2.9 ± 0.3	3.8 ± 0.1	2.4 ± 0.1	2.7 ± 0.1	2.1 ± 0.2	3.5 ± 0.5	2.5 ± 0.2	3.9 ± 0.5
	Ros-02	3.3 ± 0.6	4.2 ± 0.2	1.7 ± 0.3	4.3 ± 0.1	2.5 ± 0.2	3.4 ± 0.6	0.9 ± 0.3	2.8 ± 0.5
One-quarter-strength Ringer's (control)	Ros-91	0.1 ± 0.0	0.0 ± 0.0	0.2 ± 0.3	0.2 ± 0.1	0.1 ± 0.1	0.2 ± 0.2	0.2 ± 0.2	0.0 ± 0.1
	Ros-02	0.2 ± 0.1	0.0 ± 0.2	0.3 ± 0.2	0.2 ± 0.4	0.0 ± 0.0	0.0 ± 0.1	0.1 ± 0.1	0.1 ± 0.2

^aA. polyphaga strain Ros-02 was cryopreserved shortly after isolation in 1991 and was recovered for this study; strain Ros-91 has been in continuous axenic culture since that time.

^bThe experiments were conducted in triplicate.

^cThe values in parentheses are the log killings obtained with additional batches of Ros-91 cysts tested on a separate occasion.