ANTIMICROBIAL EFFICACY OF COMMONLY USED DISINFECTANTS AGAINST ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS

ABSTRACT

The antimicrobial effectiveness of two selected disinfectants (Izal and Jik) was determined using agar diffusion method. The test organisms used (Escherichia coli and Staphylococcus aureus) were obtained from Enugu State University Teaching Hospital, Enugu. The disinfectants were diluted to 100%, 50%, 25%, 62.5%, 12.5% concentrations. The diluted concentrations showed different zones of inhibition against the test organisms. At 100% concentration Izal completely cleared both Escherichia coli and Staphylococcus aureus while Jik had 25mm zone of inhibition for Escherichia coli and 24mm zone of inhibition for Staphylococcus aureus. At 50% concentration Izal cleared both Escherichia coli and Staphylococcus aureus while Jik had 20mm zone of inhibition for both test organisms. At 25% concentration Izal completely cleared both test organisms while Jik had 15mm zone of inhibition for Escherichia coli but no zone of inhibition for Staphylococcus aureus. At 12.5% concentration Izal completely cleared both test organisms while Jik had no zone of inhibition. At 6.25% concentration Izal completely cleared the test organisms while Jik had no zone of inhibition for the test organisms. The results showed that Izal was more effective at any concentration while Jik was effective only at high concentration of 100% and 50%. Escherichia coli and Staphylococcus aureus obtained from hospital are both susceptible to the disinfectants used in this research. Therefore, disinfectants such as Izal and Jik can help to control incessant spread of some of the hospital acquired infections when used at the right concentration.

CHAPTER ONE

1. BACKGROUND OF STUDY

INTRODUCTION

Disinfectants are chemical agents used to kill microorganism on the surface or in order to eliminate them from the environment (Melike et al, 2016).

Ever since the identification of microorganism as the causative agents of infectious diseases, various methods have been devised in reducing the population and prevalence of these organisms. The various methods embarked upon include, chemotherapy, immunization, sterilization and disinfection (Kim et al, 2007).

Disinfectants are used extensively in hospitals and other health care settings for a variety of topical and hard surface applications (Olowe et al., 2004). Chemical agents used in disinfection are referred to as disinfectants and the three main types of disinfection available are cleaning, heating and disinfection with chemical agents (Geo et al., 2004). Disinfectants take time to act, they are greatly inactivated by excess organic matter and show higher activity at adequate concentrations (Olowe et al., 2004). Disinfectants are an essential part of infection control practices and aid in the prevention of nosocomial infections (Olasehinde et al., 2008).

Disinfectants are toxic not only for microbial pathogens but for host cells as well and because of this they can only be used to inactivate microorganism in the inanimate environment (Brooks et al., 2004).

There are four classes of disinfectants. They include:

1. Sterilants: are required for critical instruments that penetrate tissue or present a high risk if non- sterile, for e.g. implants, needles and other surgical instruments. E.g. heat, steam, higher concentrations of hydrogen peroxide and paracetic acid, glutaraldehyde.
2. High level disinfectants: are required for semi- control items that do not penetrate tissues or contact mucous membranes (except dental) such as endoscopes, respiratory therapy equipment and diaphragms. Examples; hydrogen peroxide , glutaraldehyde, formaldehyde, ortho-phthaladehyde, paracetic acid.
3. Intermediate level disinfectants: are required for non-critical items that touch intact skin [e.gthermoters and hydrotherapy tanks] examples; alcohols, hypochlorite, iodine and iodophor disinfectants.
4. Low level disinfectants: are required for non-critical items such as stethoscopes, bedpans, blood pressure cuffs and bedside tables. Examples; phenolic, quaternary ammonium compounds.

1.2 STATEMENT OF PROBLEM

The current increase in the prevalence of nosocomial infections within the hospital environment despite adequate cleaning and disinfection is due to ineffectiveness of the various disinfectant formulations used in infection control and development of resistance to the various chemical disinfectant formulations being used in the hospitals by various micro-organisms

1.3AIM OF STUDY

To determine the antimicrobial activity of disinfectants used in hospitals against Escherichia coli and Staphylococcus aureus.

1.4 SPECIFIC OBJECTIVES

• To determine the disinfectants used in hospitals.
• To determine the antimicrobial activities of the disinfectants used in the hospitals against the test organisms.

To determine the Minimum inhibitory concentration of those disinfectants