ABSTRACT

To access the role of biocide in the environment and the impact of biocide resistance, a panel of biocides was evaluated for antimicrobial activity and biocide resistance patterns. Equally, plants with traditionally acclaimed biocidal activities were accessed. The samples were subjected to Disc susceptibility testing, minimum inhibitory concentration (MIC) and time-kill determination. Majority of the population use household commercial biocides including benzalkonium chloride, sodium hypochlorite, sodium carbonate, chlorophenol, choroxylenol and ammonium as well as isoprppyl alcohol and other respective combinations. Preliminary data on zone of inhibition at lmg/L{v/v) against standard E. coli and S. aureus strains for benzalkonium (Harpic®), sodium hypochlorite( Jik), chloroxylenol (Dettol®) and chlorophenol (Ivy fectant) were all resistant at < 19mm S. aureus except dettol and Izal, including Izal towards E. coli > 17mm respectively. Xylopia was the only botanical that showed biocidial activity against E.coli > 18mm. Xylopia, Azadiracha and Vernonia only showed moderate antistaphylococcal activity at high MIC value (1,024mg/L). Comparatively, Izal B had the highest to moderate inhibition effect against E. coli in the following manner Izal> Harpic > Dettol > Jik at O hr, while Ivy detergent didnt show biocidal activity at O hr contact both at MIC or double MIC value. The double MIC biocidebacterial time-kill effects were very pronounced and consistent among all the biocides suggesting that higher effect of biocides could only be enjoyed at higher concentrations and longer time contact with the oragnism. This suggests that when applying household biocide, high concentration and more time factor is needed in other to act on the applied area and to achieve inhibition of bacterial growth. The fact that biocides are used extensively in many different products and concentration contribute largely to its efficacy, while at lower dosage usage and less time contact, it remain inactive allowing the organisms to overcome the effect and thereby contribute to bacterial resistance.