TABLE 1.

Effect of a 5-min exposure to chemical agents and disinfectants on infectivity and viability of spores of E. intestinalis

Treatment	% of spores recovered	Culture titration				Flow cytometry
		Mean titera:		Pc	% Reduction	% Viabilityb:		% Reduction
		Before treatment	After treatment			Before treatment	After treatment
HCl, 0.1 N	84	90.5 (64-128)	22.6 (16-32)	0.0001	75	79	50	37
NaOH, 0.1 N	86	84.4 (64-128)	34.3 (32-64)	0.002	59	79	54	32
Surfanios, 0.2%	9	97.0 (64-256)	0 (0-0)	<10−4	100	80	23	79
Benzalkonium chloride	Aggregated spores	147.8 (128-256)	NDd		ND	ND	ND	ND
Sodium hypochlorite (chlorine, 36 g/liter)	Spores destroyed	256 (256-256)	ND		ND	ND	ND	ND
Ethanol, 70%	43	106.2 (64-256)	0 (0-0)	<10−4	100	78	23	71

^aGeometric mean (range) of the titer from 10 to 15 titrations.

^bPercent nonfluorescent (viable) spores from a count of 10,000 spores.

^cWilcoxon rank-sum test.

^dND, not done.