Stability and Efficacy of Chlorinated Disinfectants in Beninese Hospitals: Issues for the Prevention and Control of Infections and Antibiotic Resistance

In hospitals with limited resources, chlorine solutions are commonly used for biocleaning. The effectiveness of these solutions depends on the concentration of active chlorine and how they are prepared and stored. A study conducted in six University Hospitals in Benin from March 10 to July 11, 2025, aimed to evaluate the stability of active chlorine and the bactericidal efficacy of chlorine solutions used for disinfecting hospital environments. A total of 103 samples were analyzed using iodometric titration following AFNOR standard NF EN ISO 7393-3 (2000) and WHO recommendations. Bactericidal activity was tested on multi-resistant hospital strains using the germ carrier method based on standard NF T72-281. The study found that 88.4% of the solutions had inadequate active chlorine concentrations. Overall, the bactericidal efficacy was low at 14.6%, particularly ineffective against Gram-negative bacilli (79.6%) and Gram-positive cocci (84.5%). There was a significant association between compliance with active chlorine levels and bactericidal efficacy (OR = 42.5; p < 0.000001). Factors contributing to inefficiency included storage without light protection, use of transparent containers, storage for more than two days, inadequate active chlorine concentration, and incorrect pH levels. These issues compromise hospital disinfection and contribute to the persistence of multi-resistant bacteria in the hospital environment.