A Study on the Bactericidal Efficiency of Selected Chemical Disinfectants and Antiseptics

Antiseptics and disinfectants are used extensively in hospitals and other health care settings for a variety of topical and hard-surface applications. However, their antibacterial effectiveness is not  always well declared by the  manufacturers and consumers find it difficult to choose the  right product according to their needs. Therefore, the  aim of the  present study was to evaluate the  bactericidal effectiveness of selected disinfectants and antiseptics found in the  local market. Three  disinfectants and antiseptics (Dettol, Lysol and Chlorox) were assessed using phase 1, BSEN 1040; 1997, Chemical Disinfectants and Antiseptics, Basic bactericidal activity- Test method and requirements.   The in vitro  activity of these disinfectants and antiseptics against two challenge strains Staphylococcus aureus and Pseudomonas aeruginosa were analysed. All these disinfectants and antiseptics were tested at four  different concentrations and three different contact times. Results showed that using double concentration than recommended use dilution of Lysol had a significant impact on killing  both S. aureus and P. aeruginosa. Dettol achieved a 99.999%  killing  of S. aureus within 5 minutes at the recommended use dilution and 15 minute  contact time  showed to be  the best in achieving an effective killing  of P. aeruginosa at the  recommended use dilution. The results of Chlorox  indicated that a 15 minute  contact time was far more  effective against S. aureus than 5 minute contact time specified by the  manufacturer. Chlorox  achieved a 99.999%  killing  of P. aeruginosa within a contact time  of 15 minutes at all concentrations tested. It revealed that the  prolonged contact times increased the  activity of Chlorox  irrespective of the  concentration used. At 1 minute  contact time none of the  products achieved a 5 log reduction against both S. aureus and P. aeruginosa. The overall results suggest that Chlorox  was the  best disinfectant against both S. aureus and P. aeruginosa at the recommended use dilution.

DOI: http://dx.doi.org/10.4038/ouslj.v6i0.4113

OUSL Journal (2010) Vol. 6, (pp. 44- 58)