Abstract:
Disinfectants and antiseptics are chemical agents that are used to control
microorganisms. The objectives of this study were to assess the efficacy of
some selected disinfectants/antiseptics at the manufacturer-recommended
dilution (MRD) and to compare the efficacy of each product at serial
concentrations of MRD. Commercially available disinfectants/antiseptics
containing benzalkonium chloride (A), sodium hypochlorite (B), chlorinated
phenol (C) and phenol (D), were used in this study. Sterile filter-paper discs
were dipped separately in different concentrations of each product ranging
from the MRD to its serial concentrations. The discs were then incubated on
agar plates pre-spreaded with Staphylococcus aureus cultures. Mean
diameters of inhibitory zones (ZI) were measured and statistically analyzed
for differences with different products. The efficacy of each
disinfectant/antiseptic was assessed according to (ZI). Product D showed the
highest efficacy whereas product A showed the least efficacy at the MRD.
There was no difference in the efficacy of MRD, and its two-fold increase,
with product A. In contrast, products B and C showed an increase in the
efficacy (p<0.01) with each two-fold increase in the product concentration
starting from the MRD. With reference to product D, no difference was
observed with the efficacy of MRD and its two-fold increase. Further
increase of product concentration (from two-fold to four-fold) showed a
decrease in efficacy (p<0.01). In conclusion, all disinfectant/antiseptic
products of this study were effective at the MRD. However, the degree of
efficacy was different (p<0.01) among products. Certain products (A & D)
showed no increase in efficacy (p>0.01) at two-fold increase of MRD but
showed increase in the efficacy (p<0.01) at higher concentrations.