BIOSECURITY ▶▶▶
Using positive biofilms to manage the microbial environment of poultry
Every time new broilers enter a barn, biosecurity measures impact the level of microbial pressure. Integrating a protective biofilm approach has been shown to be an effective tool to complement these measures, by helping to install a positive microbial environment after the disinfection step.
BY JULIA PLATEAU-GONTHIER, LALLEMAND ANIMAL NUTRITION M
icroorganisms are everywhere. In farm build- ings, all surfaces – floors, walls, ceilings and equipment – are colonized by microorganisms, mainly in the form of biofilms (see box). They
can be harmless, positive or negative for animals, humans and even for end products if they contain undesirable bacteria. Be- fore a new flock of birds enters the building, cleaning and dis- infection are necessary. However, surfaces do not remain ster- ile. Microorganisms carried over from the animal environment and from the new birds themselves quickly start recolonizing the surfaces, forming biofilms. These microorganisms may be undesirable bacteria or potential pathogens.
A positive bacteria biofilm What if beneficial bacteria were applied to building surfaces and equipment right after cleaning and disinfection? If they could grow into a positive bacteria biofilm inside the building, that would leave less room for negative biofilms to develop. This is the basis of the ‘positive biofilm’ concept; a new approach to biosecurity management. It comprises three main steps:
cleaning, disinfection and the application of selected bacteria that will form a positive biofilm. Farm trials and in vitro studies have shown the potential for this new approach as part of the hygiene management toolbox. To develop a positive biofilm solution, Lallemand Animal Nutrition selected bacteria strains for their ability to form a biofilm and rapidly occupy the environment. The positive biofilm formed by the selected bacteria rapidly takes up the empty space on farm surfaces: in vitro testing showed 90% of surface coverage within 12 hours, leaving less room for unwanted bacteria. The selected bacteria were formulated into a specific adhesive blend that can be sprayed onto both vertical and horizontal surfaces.
Figure 1. Representation of positive biofilm interaction with S. aureus: positive biofilm alone (a), positive biofilm (green) and S. aureus (red) (b), visualisation of the S. aureus cells only (red) (c) and pure culture of S. aureus (red) (d).
36 ▶ POULTRY WORLD | No. 10, 2021
In vitro proof An external in vitro study was conducted in partnership with the INRA Micalis Institute in Paris, France. It enabled scientists to visualise the interaction between the positive biofilm and cer- tain pathogenic microorganisms of concern on farms (Staphylo- coccus aureus HG003, Listeria monocytogenes LO28, Escherichia coli SS2 and E. coli 977). Plates were inoculated either with the positive biofilm formula or the tested microorganism alone (control). After 24 hours, the tested microorganisms were added on top of the positive biofilm. Figure 1 shows one example of the visualisation of the positive and negative biofilms. To quan- tify these results, the researchers analysed the microscopic im- ages to calculate relative biofilm volumes. For the four micro- organ isms tested, pre-treatment with a positive biofilm helped to avoid colonization with undesirable microorganisms. Further in vitro studies were conducted at the Laboratory of Molecular Epidemiology (LEPIMOL), School of Veterinary Medi- cine, at the Federal University of Uberlandia, Brazil, to study the effect of the positive biofilm solution on the recolonization of various microorganisms (Salmonella gallinarum, S. heidelberg, Campylobacter jejuni and methicillin-resistant Staphylococcus aureus, or MRSA) on different types of matrices: polystyrene plates (representative of poultry housing equipment surfaces) and litter materials (soil and wood shavings) as the product is applied on farm after the building and litter set up has been in- stalled. The study showed that each microorganism grows differently according to the material (Figure 2).
ILLUSTRATION: INRA MICALIS
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