Marked variations in the effectiveness of commercial disinfectants against clinically relevant antibiotic-resistant bacteria and fungi

Abstract

Effective disinfection of noncritical hospital surfaces may be essential for limiting the transmission of antibiotic-resistant bacteria (ARB), which seem to persist despite clear disinfection guidelines and raise concern about the potency of real-world disinfectants and about the consistency of disinfection practices. This study compared the bactericidal efficacy of eight commercially available disinfectants – alcohols, hydrogen peroxide, quaternary ammonium compounds (QACs), and chlorhexidine (CHX) – against multidrug-resistant clinical isolates of Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecium, carbapenem-resistant Pseudomonas aeruginosa, and model organism Candida albicans as the most frequent causes of hospital-acquired infections in Croatia. Several formulations, particularly those based on QACs and CHX, retained full bactericidal activity even when diluted 10–32 times after only 1 min of contact, while alcohols were ineffective when diluted more than twice. However, all the formulations were effective when applied at full concentration. These findings highlight marked differences in the intrinsic bactericidal strength of commercial products, especially if not applied properly, which may explain variable outcomes observed in routine hospital disinfection practices. These issues may be overcome by rotating different disinfectant classes during routine surface decontamination and by optimising disinfectant strength to improve ARB and fungal control in clinical settings.