The Use of Raw Poultry Waste as Soil Amendment Under Field Conditions Caused a Loss of Bacterial Genetic Diversity Together with an Increment of Eutrophic Risk and Phytotoxic Effects.

Poultry waste has been used as fertilizer to avoid soil degradation caused by the long-term application of chemical fertilizer. However, few studies have evaluated field conditions where livestock wastes have been used for extended periods of time. In this study, physicochemical parameters, metabarcoding of the 16S rRNA gene, and ecotoxicity indexes were used for the characterization of chicken manure and poultry litter to examine the effect of their application to agricultural soils for 10 years. Poultry wastes showed high concentrations of nutrients and increased electrical conductivity leading to phytotoxic effects on seeds. The bacterial communities were dominated by typical members of the gastrointestinal tract, noting the presence of pathogenic bacteria. Soils subjected to poultry manure applications showed statistically higher values of total and extractable phosphorous, increasing the risk of eutrophication. Moreover, while the soil bacterial community remained dominated by the ones related to the biogeochemical cycles of nutrients and plant growth promotion, losses of alpha diversity were observed on treated soils. Altogether, our work would contribute to understand the effects of common local agricultural practices and support the adoption of the waste treatment process in compliance with environmental sustainability guidelines.

Lactobacillus strains inhibit biofilm formation of Salmonella sp. isolates from poultry.

Lactic acid bacteria (LAB) exert a strong antagonistic activity against many microorganisms including food spoilage organisms and may be used as an alternative to control biofilm formation of pathogens in food industries. The objective of this work was to investigate the ability of fifteen Salmonella strains isolated from poultry environment to form biofilms on different surfaces. In addition, the effect of Lactobacillus kefiri strains 8321 and 83113 and Lactobacillus plantarum 83114 and their surface proteins on biofilm development of Salmonella Enteritidis 115 was studied. The relationship between surface properties of bacteria (hydrophobicity, autoaggregation and coaggregation with lactobacilli) and biofilm formation was also investigated. Most of Salmonella strains were hydrophilic and five strains were moderately hydrophobic. In general, Salmonella strains showed high aggregation abilities (27-54%). S. Enteritidis 106 and S. Typhimurium 102 and 108 showed the highest percentages of autoaggregation. All Salmonella strains tested showed aggregation abilities with the three lactobacilli studied, but the percentage of coaggregation proved to be strain-specific. When comparing stainless steel, glass and polystyrene surfaces, higher levels of biofilm formation occurred on polystyrene plate than on glass surfaces or stainless steel. S. Enteritidis 115 exhibited the greatest attachment to polyestyrene surface. The preincubation or coincubation with the three lactobacilli strains significantly reduced (about 1 log CFU/ml of reduction) the ability of S. Enteritidis 115 to form biofilm compared to the control without lactobacilli. These results were confirmed by confocal microscopy. In the same way, when surface proteins extracted from lactobacilli strains were preincubated or coincubated with S. Enteritidis 115, biofilm formation of this strain was significantly decreased compared to the control. The results obtained showed that these Lactobacillus strains and their surface proteins can be used as alternatives for control of biofilm formation by Salmonella in the poultry industry.

Biofilm formation by Salmonella sp. in the poultry industry: Detection, control and eradication strategies.

Salmonella represents an important global public health problem and it is an emerging zoonotic bacterial threat in the poultry industry. Diverse registered human cases of salmonellosis shown poultry origins. Various control measures have been employed both at the farming and processing levels to address it. This review focuses on traditional and new detection techniques of biofilm formation by Salmonella spp. and different approaches that can be used to prevent and/or control biofilm formation by these bacteria. A number of methodologies based on different approximations have been recently employed to detect and evaluate bacteria attached to surfaces, including real-time polymerase chain reaction (PCR), confocal laser scanning microscopy and Optical Coherence Tomography. Due to persistence of Salmonella biofilm in food processing environments after cleaning and sanitation, control and eradication strategies in poultry industry should be constantly studied. In this sense, the use of several alternatives to control Salmonella biofilm formation, such as lactic acid bacteria, phagetherapy, extracts from aromatic plants, quorum sensing inhibitors, bacteriocins and nanomaterials, have been successfully tested and will be reviewed.