In Vitro Investigation of the Antibacterial Activity of Nine Commercial Water Disinfectants, Acidifiers, and Glyceride Blends against the Most Important Poultry Zoonotic Bacteria

Abstract

Identifying and monitoring the efficiency of alternative biocides that are presently used in livestock is gaining vast attention. The objective of this study was to determine, in vitro, the antibacterial activity of nine commercial water disinfectants, acidifiers, and glyceride blends against clinical isolates or reference strains of zoonotic pathogens belonging to the genera Escherichia spp., Salmonella spp., Campylobacter spp., Listeria spp., and Staphylococcus spp. For each product, the antibacterial activity was tested in concentrations ranging from 0.002 to 1.136% v/v and expressed as the minimum concentration of the product that inhibits bacterial growth (MIC). Water disinfectants Cid 2000™ and Aqua-clean^® recorded MICs ranging from 0.002 to 0.142% v/v, while the lowest MICs were recorded at two strains of Campylobacter (0.002-0.004% v/v). Virkon^® S displayed various MICs (0.013-0.409% w/v) and was highly effective at suppressing the growth of Gram-positive bacteria such as S. aureus (0.013-0.026% w/v). The MICs of water acidifiers (Agrocid Super™Oligo, Premium acid, and Ultimate acid) and glyceride blends (CFC Floramix, FRA^®LAC34, and FRA^®Gut Balance) ranged from 0.036 to 1.136% v/v, and for most of these products, MICs were closely correlated by their ability to modify the pH of the culture medium close to 5. In conclusion, most of the tested products showed promising antibacterial activity; as a result, they would be good candidates for pathogen control in poultry farms and for reducing the emergence of antimicrobial resistance. However, further in vivo studies are recommended to provide relevant information for the underlying mechanisms, as well as for the establishment of the optimal dosage scheme for each product and their possible synergies.

Keywords: antibacterial activity; glyceride blends; minimal inhibitory concentration (MIC); organic acids; poultry; water acidification; water disinfection; zoonotic bacteria.

Figure 2

Graphical portrayal of the recorded MICs (columns; mean %v/v ± SD) of the tested commercial water disinfectants on the tested bacteria strains and of the pH value (triangles on the pH line) of the broth medium in each MIC.

Figure 3

Graphical portrayal of the recorded MICs (columns; mean %v/v ± SD) of the tested commercial water acidifiers on the tested bacteria strains and of the pH value (triangles on the pH line) of the broth medium in each MIC.

Figure 4

Graphical portrayal of the recorded MICs (columns; mean %v/v ± SD) of the tested commercial water glycerides blends on the tested bacteria strains and of the pH value (triangles on the pH line) of the broth medium in each MIC.

Figure 5

A panel of graphical presentations received from statistical analysis of the MICs (columns; mean %v/v ± SD) of the tested commercial products (1–9) against the tested bacteria (for bacterial species for which we tested more than one isolate) by the GraphPad Prism (version 9.5.0 for Windows^®, GraphPad Software, San Diego, CA, USA). 1: Cid 2000™; 2: Aqua-clean^®; 3: Virkon^® S; 4: Agrocid Super™Oligo; 5: Premium acid; 6: Ultimate acid; 7: CFC Floramix; 8: FRA^® LAC34; 9: FRA^® Gut Balance. *: p < 0.05, **: p < 0.01, ***: p < 0.001, ****: p < 0.0001.

Figure 1

Illustrative scheme of the micro-dilution MIC method that was used for the investigation of the antibacterial activity of commercial water disinfectants, acidifiers, and glyceride blends against the most important poultry zoonotic bacteria.