Thesis Abstract

Ethanol, Bleach and Phenolics are three kinds of disinfectants which have been widely used in common laboratories.  In this study, a compared experiment on these three disinfectants efficiency was conducted against Staphylococcus aureus and Pseudomonas aeruginosa using agar hole diffusion method. Different concentrations of bleach (1%, 2%, 3%, 4% and 5%) were used on both organisms.  Also (50%, 60%, 70%, 85% and 95%) of ethanol as well as (5%, 10%, 20%, 25%, and 30%) Phenolics were used. Diffrences in  concentrations tested was because, the original concentrations of the disinfectants differs. After 24 hours of incubation at 370C, the results showed that all the disinfectants inhibited the growth of the test organism in their concentrated forms.  The diameter of zone of inhibitions were measured around each well by using a ruler in millimeters, using different concentrations, their efficacies varied.  The results showed that 30% Phenolics had the best efficiency against both test organisms and 5% bleach had a better effect on Staphylococcus aureus than Pseudomonas aeruginosa, while ethanol showed least sensitivity. 70% concentration gave the highest effect on Staphylococcus aureus as compared withPseudomonas aeruginosa.

Thesis Overview

1.0       INTRODUCTION

            Microorganisms are minute living things that individually are too small to be seen with the unaided eyes (Tortora et al, 2007).  Though only a minority of microorganisms are pathogenic (disease producing), practical knowledge of microbes is necessary for medicine and related health sciences.  For example hospital workers must be able to protect patients from common microbes that are normally harmless but pose a threat to the sick and injured.  Thousands of people died in devastating epidemics; the cause of which was not understood.  Entire families died because vaccination and antibiotics were not available to fight infection (Johnson and Case, 1995).  This leads to scientific control of microbial growth.  This began only about 100 years ago.  It was Pasteur’s work on microorganism that led scientists to believe that microbes were a possible cause of diseases and need to be eliminated or destroyed.  Some examples off these microbes are; Bacteria, fungi, viruses and protozoa etc (Tortora et al, 2007).