The effect of exposure to sub-inhibitory concentrations of hypochlorite and quaternary ammonium compounds on antimicrobial susceptibility of Pseudomonas aeruginosa

Publication date: July 2018
Source:American Journal of Infection Control, Volume 46, Issue 7
Author(s): Aya Mahmoud Nasr, Marwa Salah Mostafa, Heba Hamed Arnaout, Amal Ali Ali Elshimy
BackgroundPseudomonas is a group of medically important species that inhabit a wide range of niches, including hospital environments. Controversies have emerged about the possible link between improper use of disinfectants and the emergence of antibiotic resistance in bacteria. The aim of this study was to assess the effect of exposure of antibiotic-susceptible Pseudomonas isolates to sub-inhibitory concentrations of 2 disinfectants—didecyldimonium chloride and sodium hypochlorite—on their antibiotic susceptibility patterns.MethodsThis study involved 50 Pseudomonas isolates. The antibiotic susceptibility patterns of the isolates were assessed using broth microdilution method. The minimal inhibitory concentrations (MICs) of each antibiotic were compared before and after exposure to sub-inhibitory concentrations of didecyldimonium chloride and sodium hypochlorite.ResultsAfter overnight incubation with sub-inhibitory concentrations of sodium hypochlorite, a statistically significant increase was observed in the MICs of colistin (P = .012), ceftazidime (P < .001), amikacin (P < .001), meropenem (P < .001), gentamicin (P < .001), piperacillin-tazobactam (P = .003), and ciprofloxacin (P = .004). In contrast, exposure to sub-inhibitory concentrations of didecyldimonium chloride showed a statistically significant increase in the MICs of amikacin (P < .001), gentamicin (P < .001), meropenem (P = .041), and ciprofloxacin (P = .008).ConclusionsThe use of suboptimal concentrations of sodium hypochlorite and didecyldimonium chloride can lead to the evolution of antibiotic-resistant Pseudomonas strains.



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