TABLE 1

Bactericidal effect of increasing exposure times and acid concentrations

Acid and/or conditionsSolution characteristicsaLog10 reduction of viable bacteriab
BSA and RBC concn (%)cpHpH with M. abscessusdMolar concnExposure time (min)Final concn (%)E. coli DH5αE. coli survivorsM. smegmatisM. smegmatis survivorsM. tuberculosis mc27000M. tuberculosis H37RvMDR
M. tuberculosis
XDR
M. tuberculosis
M. abscessusM. bolletiiM. massiliense RfM. massiliense S.f
Acetic acid0.34202.532
0.40303443
0.542043433
2.452.620.832058.577734.534
0.832555
0.833057e5
2.432.571.002569e5.542
1.003068e7e8e8e8e8533
2.312.421.333088e8e8e74.55
2.272.401.6730108e8e8e8e666
Acetic acid,
dirty conditions
22066
32567
3.52579e
2.530108e
Propionic
acid
0.9206.78e
1.08208.07
1.08258.07
1.15208.58e
  • a High-level disinfectant activity is indicated in bold.

  • b The 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.

  • c BSA, bovine serum albumin; RBCs, human red blood cells.

  • d M. abscessus with optical density at 600 nm of 1 was diluted 1:10 in the acetic acid solutions.

  • e Limit of detection (no colonies recovered from exposed bacteria).

  • f R and S refer to the rough and smooth morphotypes of M. massiliense.