Traditional vs Innovative Sanitizers: In Vitro and In Situ Challenge in Multidrug-Resistant Bacteria

Multidrug-resistant (MDR) bacteria pose a threat to public health worldwide. In this context, disinfectants are used to prevent and control the spread of these pathogens in hospital and industrial environments. The objective of this study was to determine minimum bactericidal concentrations (MBC) for 10 traditional and innovative active ingredients against 11 bacterial species. At the same time, the efficiency test was applied in vitro and the effect on hospital surfaces was analyzed in situ. The most promising compounds were selected to determine their mechanism of action in the Gram-positive bacterium (Staphylococcus aureusMRSA) and the Gram-negative bacterium (Pseudomonas aeruginosaPA) by metabolomic analysis. Resistance to 50% of the active ingredients was observed in the five strains, and PA was resistant to 70% of them. Peracetic acid, chlorhexidine digluconate, and neem extract eliminated all strains within 1 min in MBC. In efficiency tests, traditional products killed bacteria, with an average reduction of 7.07 ± 0.331 log cycles. Neem extract achieved an average reduction of 6.60 ± 0.33 log across all strains. In situ, peracetic acid did not allow bacterial growth, while biguanide, neem extract, tea tree oil, and orange oil achieved a reduction of more than 4 cycles of bacterial control on the surface. The exposure of MRSA and PA to the most promising compounds promoted distinct alterations in intra- and extracellular metabolism, which were modulated by the bacterial cell wall structure. The study highlights the importance of evaluating the practical efficacy of disinfectants, emphasizing the diversity of approaches including natural compounds as alternatives in critical environments.