Abstract

The ever-rising numbers of multidrug resistant, MDR bacteria in healthcare facilities globally has correspondingly
led to a rapid escalation in the use of disinfectants, antiseptics or biocides which reached unprecedented levels during
the COVID-19 pandemic. This has also elicited grave apprehension about the development of resistance to
disinfectants. This study was conducted to evaluate the effectiveness of some regularly used disinfectants in the
study population. Five brands of disinfectants were obtained and diluted in sterile 300 ppm calcium carbonatenutrient
broth to their respective minimum inhibitory concentrations, MICs to which were exposed broth cultures
of MDR organisms for 2 min before sampling onto nutrient agar plates in replicates. Further samples were taken from the mixture at 4, 6, 8, … 30 min intervals. One set of plates were incubated at 37oC and the other at RT for 48
h and 96 h respectively and examined for growth. Sodium hypochlorite, phenol and glutaraldehyde - all proved to
be effective with the fastest time kill kinetics at 2.5 min. The longest time kill kinetics were demonstrated by
cetrimide and cresol against Pseudomonas aeruginosa at 16 min and 13 min respectively, thus affirming Pseudomonas
aeruginosa as the most resistant organism. This study infers of a reassurance in the continued effectiveness of the
disinfectants under review in the phase of the ever-soaring tide of MDR organisms in healthcare settings