EFFECTIVENESS OF DISINFECTANTS AGAINST MULTIDRUG-RESISTANT PATHOGENS ISOLATED FROM CLINICAL ENVIRONMENTS

Abstract

Healthcare facilities face the persistent transmission of multidrug-resistant (MDR) pathogens on high-touch surfaces and equipment. This study evaluated the effectiveness of commonly deployed disinfectants against MDR clinical isolates recovered from wards, intensive care units, and procedure rooms. Non-duplicate isolates were identified and resistance profiles were confirmed using standard methods. The efficacy of sodium hypochlorite, quaternary ammonium compound formulations, chlorhexidine, hydrogen peroxide, and peracetic acid was assessed using quantitative suspension and carrier tests under clean and organic load conditions at manufacturer-recommended concentrations and contact times. Oxidizing agents, particularly accelerated hydrogen peroxide and peracetic acid, demonstrated consistent broad-spectrum activity against MRSA, VRE, ESBL-producing Enterobacterales, and non-fermenters such as Pseudomonas aeruginosa and Acinetobacter baumannii, achieving target log reductions within short contact periods. Sodium hypochlorite met the performance criteria when free chlorine was adequate but showed variability at suboptimal concentrations and in the presence of soil. Quaternary ammonium compounds alone were less reliable against non-fermenters and showed reduced activity with organic load, whereas chlorhexidine had limited efficacy on environmental surfaces. Biofilm assays have indicated diminished susceptibility to mature biofilms, necessitating higher concentrations or extended contact times. The findings support the careful selection of disinfectants, verification of in-use concentrations, strict adherence to contact time, and enhanced protocols for biofilm-prone sites to strengthen infection prevention programs.