The efficacy and stability of five sanitizing agents challenged with reference microorganisms and clean area isolates

Abstract

The antimicrobial activity of five sanitizing agents employed in clean areas designated for the pharmaceutical manufacturing of sterile products was tested against nine microorganisms, including four microorganisms from the clean area microbiota. The method consisted of challenging 5 mL of each sanitizing agent - 70% isopropyl alcohol, 0.4% LPH®, 1.16% hydrogen peroxide, 4% hydrogen peroxide, 1% Bioper® and 5% phenol - with 0.1mL each of concentrated suspensions (105 – 106 CFU/ mL) of Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. and Bacillus sp. for 10 minutes, followed by serial dilutions and plating. The results demonstrated that the five agents were effective against S. aureus, C. albicans, Corynebacterium sp., and M. luteus. The same was true of E. coli, except that isopropyl alcohol showed low levels of inactivation. With A. niger, isopropyl alcohol, 0.4% LPH® and hydrogen peroxide were more effective and 5% phenol and 1% Bioper® less effective. 1% Bioper® and 4% hydrogen peroxide showed greater inactivation of Staphylococcus sp., Bacillus sp. and B. subtilis than the other agents. Against S. aureus, C. albicans, Corynebacterium sp. and M. luteus, 5% phenol showed similar activity to other agents, while with A. niger, B. subtilis, Staphylococcus sp. and Bacillus sp., it was similar to or less active than the other agents. It was demonstrated that two microorganisms from the clean area microbiota, Staphylococcus sp. and Bacillus sp., were the most difficult to eradicate, requiring more frequent application of hydrogen peroxide and 1% Bioper® than the other strains.