Does the Wide Use of Quaternary Ammonium Compounds Enhance the Selection and Spread of Antimicrobial Resistance and Thus Threaten Our Health?

Abstract

Quaternary ammonium compounds (QACs) are widely used biocides that possess antimicrobial effect against a broad range of microorganisms. These compounds are used for numerous industrial purposes, water treatment, antifungal treatment in horticulture, as well as in pharmaceutical and everyday consumer products as preserving agents, foam boosters, and detergents. Resistance toward QACs is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as modifications in the membrane composition, expression of stress response and repair systems, or expression of efflux pump genes. Development of resistance in both pathogenic and nonpathogenic bacteria has been related to application in human medicine and the food industry. QACs in cosmetic products will inevitably come into intimate contact with the skin or mucosal linings in the mouth and thus are likely to add to the selection pressure toward more QAC-resistant microorganisms among the skin or mouth flora. There is increasing evidence of coresistance and cross-resistance between QACs and a range of other clinically important antibiotics and disinfectants. Use of QACs may have driven the fixation and spread of certain resistance cassette collectors (class 1 integrons), currently responsible for a major part of antimicrobial resistance in gram-negative bacteria. More indiscriminate use of QACs such as in cosmetic products may drive the selection of further new genetic elements that will aid in the persistence and spread of antimicrobial resistance and thus in limiting our treatment options for microbial infections.

Quaternary ammonium compounds in soil: implications for antibiotic resistance development

“…Enzymatic biotransformation by amine oxidase was reported for BAC at 20 nmol mg protein -1 min -1 (Ertekin et al 2016) and QAAC half-lives were on the order of hours (Tezel et al 2012). However, due to adsorption processes even aerobic biodegradation is often incomplete or significantly slowed down (Fenger et al 1973;Boethling 1984;Tezel et al 2006) and overall rather poor (Hegstad et al 2010a), likely due to sorption processes reducing the bioaccessibility of QAACs. Usually, a portion of the total concentration of a pollutant in soil may be taken up by microorganisms, commonly equated with the so-called bioavailable or bioaccessible fraction (Semple et al 2004;Hatzinger and Alexander 1995;Jechalke et al 2014).…”

“…Usually Gram-positive bacteria are more susceptible to QAACs than Gram-negative bacteria due to the lack of the outer membrane, while QAACs are not lethal to bacterial spores and mycobacteria (White and McDermott 2001;Hegstad et al 2010a). …”

“…This can, for example, be caused by an increased expression of energy-driven drug efflux systems such as the AcrAB pump or the NorA and MdeA multidrug efflux systems that can extrude QACs as well as multiple antibiotics (Levy 2002;Poole 2005;Hegstad et al 2010b). …”

Identification of the mechanisms of resistance and potential cross resistance of Listeria monocytogenes upon adaptation to different antimicrobials

“…For the change resistance, 960 mutants of F2365 and 960 mutants of 10403S were screened. The mutants grown in BHI on 96-well microtiter plates were spotted on BHI supplemented with10,20,40,60,100,150,200, 400µM/ml, respectively, using a sterile 48-pin replicator. The plates were air-dried and incubated at 37oC for 2 days.…”

“…Escherichia coli, Salmonella, and Pseudomonas) following exposure to disinfectants, although other mechanisms (e.g. envelope changes) have also been implicated (18,100,112,181,205).…”