Antimicrobial Science News: February 2026
By Rebecca Fuoco | February 14, 2026
More and more studies are being published on the harms—and often, lack of benefit—of antimicrobials but are flying under the radar. In these newsletters we will be sharing notable new peer-reviewed research related to quaternary ammonium compounds (QACs) and other antimicrobials used in consumer products.
In the past month, there have been studies published finding lack of efficacy, environmental contamination, and human exposure, as well as links to neurological harm, endocrine disruption, dermatitis, and antimicrobial resistance:
Health Harms
- QACs inhibited 5α-reductase 1, a key enzyme in brain neurosteroid synthesis, which is critical for maintaining brain function. This “suggests potential risks to brain health.” (Wenzhou Medical University)
- A case report documented a hospital cleaning staff member with acute airborne contact dermatitis shortly after working with aerosolized QAC disinfectant. (All India Institute of Medical Sciences)
- A study presented "strong evidence" that benzalkonium chloride spuresses a crucial human and rat regulatory protein responsible for converting cortisol to cortisone. The authors say that benzalkonium chlorides are "potent environmental endocrine disruptors, warranting urgent re-evaluation of their safety guidelines." (Wenzhou Medical University)
Antimicrobial Resistance
- Subinhibitory exposure to benzalkonium chloride and other disinfectants induced tolerance development in L. monocytogenes. (Autonomous University of Barcelona)
- K. pneumoniae adaptation to two QACs was associated with the modification of lipid A causing the reduction of the net-negative charge of the outer surface, lowering the affinity of cationic disinfectants. This mechanism is also used for polymyxin and colistin resistance, highlighting a potential cross-resistance risk. (University of Southampton)
- A study of a Listeria monocytogenes strain commonly associated with food contamination identified new pathways linked to reduced benzalkonium chloride susceptibility and biofilm persistence. The authors say the findings “highlight the need for biocide management strategies that limit the selection of efflux-based tolerance mechanisms. (Quadram Institute Bioscience)
Lack of Benefit
- A study of four commercially available antimicrobial surface treatment sprays (three QAC-based and one silver-based) found no significant reduction in microbes in real-world settings. The authors note that in contrast to laboratory studies, “none of the tested sprays proved effective in real-life settings. This indicates that the efficacy of surface treatment sprays must always be evaluated under real-world conditions.” (University of South-Eastern Norway)
- Chlorine and steam were more effective than QACs, silver, and other disinfectants in killing viruses on reusable porous material. (Clemson University)
Human Exposure
- QACs were ubiquitously detected in dust and air in homes and on hands. The researchers estimated that ingestion of surface residues was the dominant exposure route for many QACs. (Southern University of Science and Technology)
- QACs were found to be building up inside assisted living facilities. The researchers estimated that accidental ingestion of contaminated indoor dust was the primary route of exposure for residents, followed by skin contact with treated surfaces. (Emory University)
Environmental Contamination
- A study of a New York lake found a clear spatial gradient in QAC concentrations suggested transport of these chemicals from creeks to lake inshore, with subsequent transport to offshore waters. (New York State Department of Health)
- A study of QAC-treated textiles found that most released more than half of the QACs after washing, with the laundry wastewater causing dose-dependent immobilization of Daphnia magna. The authors concluded that "QAC-treated textiles not only fail to maintain long-term antimicrobial efficacy but also contribute to continuous low-level environmental exposures, raising concerns about their essential use in nondisposable textile materials." (Southern University of Science and Technology)