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

ABSTRACT The aim of the study was to determine the antimicrobial activity of disinfectants used in hospitals against Escherichia coli and Staphylococcus aureus to aid in the control of nosocomial infections. Dettol and Izal were obtained from Wurukum market, Makurdi. The test organisms were inoculated on nutrient agar and 2-fold serial dilution was carried out for each of the disinfectants in 100, 50, 25, 6.25 and 3.13mg/ml concentration using Trypticase soy broth. The dilutions were poured into wells bored on the inoculated agar and the zones of inhibition were recorded. Dettol disinfectant was inhibitory against both test organisms, Escherichia coli and Staphylococcus aureus, at 100mg/ml, 50mg/ml, 25mg/ml, and 12.5mg/ml. Izal exhibited a level of inhibitory activity against the selected bacteria at the highest concentrations. It inhibited the growth of Staphylococcus aureus at only 100mg/ml and Escherichia coli at 100mg/ml and 50mg/ml alone. Escherichia coli and Staphylococcus aureus obtained from a diagnostic laboratory were susceptible to Izal at high concentrations only while both test organisms were susceptible to Dettol at almost all concentrations. Therefore, disinfectants such as Dettol and Izal can help to control the spread of some of the hospital-acquired infections when used at the appropriate concentrations.