Novel eradication methods for Staphylococcus aureus biofilm in poultry farms and abattoirs using disinfectants loaded onto silver and copper nanoparticles.

Recent developments in the nanotechnology field have created opportunities to design new biomaterials for Staphylococcus aureus biofilm eradication. These biomaterials including disinfectant-loaded nanoparticles could overcome the limitations of conventional disinfectants. The objective of this study was to assess the biocidal activity of five commercial disinfectants (DC&R®, VirkonS®, TH4++, Tek-Trol, and peracetic acid) alone and as with silver and copper nanocomposites on S. aureus biofilm at different concentrations and exposure times. Consequently, 227 samples were collected from two broiler farms, two-layer farms, and three abattoirs at El-Dakahlia Province, Egypt, during summer 2018. The samples were collected from birds as well as the surrounding environment. S. aureus strains were isolated and biofilm producers were phenotypically evaluated by Congo red agar (CRA) test. Besides, 4 biofilm-associated genes including bap, fnbA, cna, and ebps were genotypically detected by PCR technology. Out of 227 collected samples, 141 (62.1%) strains were identified as S. aureus, while 127 strains (90.1%) were S. aureus biofilm producers for all examined samples except for hand swabs of abattoir workers. The prevalence of fnbA and bap genes was 79.5% (101/127) and 20.5% (26/127), respectively but, no strains harbored cna or ebps genes. Tested nanocomposites were prepared using an aqueous solution of metal salts such as copper sulfate and silver nitrate and added to the same amount of disinfectant solution. The obtained nanocomposites were characterized by transmission electron microscopy (TEM) and zeta potential which showed spherical and elongated particles and with a surface charge of disinfectants-silver and copper nanocomposites-of 2.92 and 3.43 mV, respectively. Complete eradication of S. aureus biofilm was observed after treatment with disinfectants loaded onto silver (AgNPs) and copper (CuNPs) nanoparticles in varying concentrations as well as at different exposure times in comparing to disinfectants alone. Our results exhibited the potential applications of disinfectant nanocomposites in complete eradication of S. aureus biofilm in farms and abattoirs without developing of disinfectant resistant bacteria.