TABLE 1.

Bactericidal effect of increasing exposure times and acid concentrations

Acid and/or conditions	Solution characteristicsa						Log10 reduction of viable bacteriab
	BSA and RBC concn (%)c	pH	pH with M. abscessusd	Molar concn	Exposure time (min)	Final concn (%)	E. coli DH5α	E. coli survivors	M. smegmatis	M. smegmatis survivors	M. tuberculosis mc27000	M. tuberculosis H37Rv	MDR M. tuberculosis	XDR M. tuberculosis	M. abscessus	M. bolletii	M. massiliense Rf	M. massiliense S.f
Acetic acid				0.34	20	2.5			3						2
				0.40	30	3						4	4	3
				0.54	20	4						3	4	3	3
		2.45	2.62	0.83	20	5	8.5	7	7	7		3	4.5	3	4
				0.83	25	5									5
				0.83	30	5					7e				5
		2.43	2.57	1.00	25	6			9e						5.5		4	2
				1.00	30	6			8e		7e	8e	8e	8e	8	5	3	3
		2.31	2.42	1.33	30	8						8e	8e	8e		7	4.5	5
		2.27	2.40	1.67	30	10			8e			8e	8e	8e		6	6	6
Acetic acid, dirty conditions	2				20	6			6
	3				25	6			7
	3.5				25	7			9e
	2.5				30	10											8e
Propionic acid				0.9	20	6.7	8e
				1.08	20	8.0									7
				1.08	25	8.0									7
				1.15	20	8.5	8e

^aHigh-level disinfectant activity is indicated in bold.

^bThe numbers represent the reductions, expressed in log₁₀, in the number of colonies recovered after the acid exposures, compared to that of controls exposed to sterile water alone under the same conditions.

^cBSA, bovine serum albumin; RBCs, human red blood cells.

^dM. abscessus with optical density at 600 nm of 1 was diluted 1:10 in the acetic acid solutions.

^eLimit of detection (no colonies recovered from exposed bacteria).

^fR and S refer to the rough and smooth morphotypes of M. massiliense.