Effects of Quaternary-Ammonium-Based Formulations on Bacterial Community Dynamics and Antimicrobial Susceptibility

Abstract

Quaternary ammonium compounds (QACs) are widely used as adjuncts to hygiene in domestic cleaning products. Current concern that the increased use of such biocides in consumer products might contribute to the emergence of antibiotic resistance has led us to examine the effects of a QAC-containing domestic cleaning fluid on the population dynamics and antimicrobial susceptibility of domestic sink drain biofilm communities. QAC susceptibilities of numerically dominant, culturable drain bacteria (15 genera, 17 species) were determined in vitro before and after repeated QAC exposure (14 passages). A fully characterized drain microcosm was then exposed to short-term (12 days) and long-term (3 months) dosing with a QAC-containing domestic detergent (QD). QAC exposure of isolated cultures caused both increases (three species) and circa twofold decreases (six species) in QAC susceptibility. The susceptibility of Ralstonia sp. was considerably decreased following 14 consecutive QAC passages. Control drain microcosm biofilms maintained dynamic stability, as evidenced by culture and denaturing gradient gel electrophoresis (DGGE) analysis. Bacterial population densities were largely unaffected during short-term exposure to use levels of QD, although 50% QD caused circa 10-fold viability reductions. DGGE analysis supported these observations; identified the major microcosm genera as Pseudomonas, Pseudoalteromonas, Erwinia, and Enterobacter, and showed that aeromonads increased in abundance under 10 to 50% QD. Long-term exposure of the microcosms to QD did not significantly alter the pattern of antimicrobial susceptibility. These data demonstrate the recalcitrance of domestic drain biofilms toward QAC and that although repeated QAC exposure of drain isolates in pure culture results in susceptibility change in some test bacteria, such changes do not necessarily occur within complex communities.

Bacterial spot and early blight biocontrol by epiphytic bacteria in tomato plants

“…The sanitizer (benzalkonium chloride) reduced the pathogen population on the phylloplane by 80.4%, while the antagonists P. macerans and B. pumilus reduced it by 68 and 70%, respectively, compared to PBS. These results confirm the antibacterial activity of the sanitizer against the phytobacteria, which was already expected, since quaternary ammonium based compounds possess fungicidal, bactericidal, algicidal and virucidal action (Mcbain et al, 2004;Oosterhof et al, 2006;Abreu et al, 2008). The antagonists probably acted on the reduction of the pathogen population by multiple mechanisms, such as competition for space and nutrients, antibiosis, and, possibly, resistance induction (Lindow & Brandl, 2003;Monier & Lindow, 2004Halfeld-Vieira et al, 2006).…”

Quaternary ammonium compounds in soil: implications for antibiotic resistance development

“…While repeated QAC exposure of drain isolates in pure culture could change their QAC susceptibility, domestic sink drain biofilm communities were recalcitrant to QAC exposure, and even longterm exposure to sub-lethal levels did not significantly affect their susceptibility to QACs or to antibiotics tested (McBain et al 2004). Enterobacter sakazakii was less affected by disinfectants containing QACs when growing in biofilms than when dried on stainless steel or growing as plankton (Kim et al 2007).…”

Influence of different sanitizers on food contaminant bacteria: effect of exposure temperature, contact time, and product concentration

“…The resistance of some microorganisms to quaternary ammonium is has been reported in some studies present in the literature (MCBAIN et al, 2004;SIDHU;SORUM;HOLCK, 2002). The focus on food security and production of refrigerated food prepared to consumption led to an increase in the use of this sanitizer in food industries.…”