Novel approach for controlling resistant Listeria monocytogenes to antimicrobials using different disinfectants types loaded on silver nanoparticles (AgNPs)
Research Abstract
A combined use of Nano-silver (AgNPs) with different types of disinfectants as antimicrobial might be useful in mitigating the problem of development of bacterial resistance with a strong enhancement of the biocidal effect of disinfectants. To evaluate the biocidal activity of Nano-silver and its loaded forms; five commercial disinfectants [quaternary ammonium compounds (benzalkonium chloride-BC and TH4+), Virkon®S, sodium hypochlorite, and hydrogen peroxide (H2O2)] against Listeria monocytogenes (L. monocytogenes) isolates at different concentrations and exposure times and to reveal intra-species variability and the percentage of resistance to antimicrobial agents used. Therefore, a total of 260 specimens from animal and human stool as well as environmental samples from dairy cattle farms were cultured for isolation of L. monocytogenes. Thereafter, bacterial isolates were identified using PCR. Nano-silver was synthesized using chemical reduction. Both Nano-silver and its loaded forms were characterized by transmission electron microscopy (TEM). The sensitivity test of 60 strains of L. monocytogenes bacteria to AgNPs and its loaded forms were evaluated using broth macro dilution method. Virkon®S/AgNPs 2.0% exhibited the highest bactericidal effect (100%) against L. monocytogenes strains followed by H2O2/AgNPs 5.0% and TH4+/AgNPs 1.0% (90% each). Furthermore, the percentage of resistance of L. monocytogenes was 0.0% to both H2O2/AgNPs 5.0% and Virkon®S/AgNPs 2.0%. In conclusion, monitoring the main source of contamination with Listeria monocytogenes in dairy cattle farms is an essential factor to achieve an efficient control. Moreover, the use of the disinfectants; Virkon®S 2.0%, H2O2 5.0% and TH4+1.0% loaded on Nano-silver composite had the strong bactericidal effect against L. monocytogenes.
Research Keywords
Keywords Listeria monocytogenes. Antimicrobial Resistance. AgNPs. Disinfectants. Disinfectants/Nano-silver composite