Salmonella enterica isolates from layer farm environments are able to form biofilm on eggshell surfaces

Abstract

This study examined the eggshell biofilm forming ability of Salmonella enterica isolates recovered from egg farms. Multicellular behaviour and biofilm production were examined at 22 and 37°C by Congo red morphology and the crystal violet staining assay. The results indicated that the biofilm forming behaviour of Salmonella isolates was dependent on temperature and associated with serovars. Significantly greater biofilm production was observed at 22°C compared with 37°C. The number of viable biofilm cells attached to eggshells after incubation for 48 h at 22°C was significantly influenced by serovar. Scanning electron microscopic examination revealed firm attachment of bacterial cells to the eggshell surface. The relative expression of csgD and adrA gene was significantly higher in eggshell biofilm cells of S. Mbandaka and S. Oranienburg. These findings demonstrate that Salmonella isolates are capable of forming biofilm on the eggshell surface and that this behaviour is influenced by temperature and serovar.

A Long-Term Efficacy Trial of a Live, Attenuated Salmonella Typhimurium Vaccine in Layer Hens

“…Horizontal contamination occurs when an egg contacts a contaminated environment ( Gantois et al, 2009 ). Bacteria can then adhere to the surface of the egg and migrate into eggshell pores ( Gantois et al, 2009 ) or form biofilms on the shell surface ( Pande et al, 2016b ) representing a risk for downstream contamination of food items. In Australia, S. Enteritidis is not endemic on commercial poultry farms ( OzFoodNet Working Group, 2015 ), thus, S. Typhimurium contamination of the layer hen farm environment represents an important public health issue.…”

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

“…Scanning electron microscopy (SEM) is based on surface scattering and absorption of electrons achieving high depth yielding a 3-D appearance, and allows the visualization special of the biofilm and to know the distribution of bacteria and EPS dispersed on biofilms (Clayborn, Adams, Baker, & Ricke, 2015). SEM has been used to study the ability of bacteria to develop biofilms on different substrates and several environmental conditions (Pande, McWhorter, & Chousalkar, 2016;De Oliveira et al, 2014). It allows the quantification of area, volume and thickness of the biofilm (Azeredo et al 2017) with a high resolution (50 to 100 nm) and depth of field with a wide range of magnifications (20 to 30000 X).…”

“…The relative expression of genes involved on curli, fimbriae and cellulose production (csgD, csgB, adrA and bapA) has permitted to detected biofilm formation by Salmonella on eggshells (Pande, McWhorter, & Chousalkar, 2016). However, expression of these gens and subsequent biofilm formation is influenced by growth media, indicating a strong dependence of environmental conditions on biofilm formation (Wang, Dong, Wang, Xu, & Zhou, 2016).…”

Salmonella and Campylobacter biofilm formation: a comparative assessment from farm to fork

“…A major problem related to this pathogen is that Salmonella normally causes asymptomatic intestinal infections in birds over 2 months, facilitating the spread of this pathogen among flocks. In this sense, Pande et al . demonstrated that Salmonella strains isolated from egg farms and belonging to different serotypes were able to form biofilms on eggshell surfaces under different temperature conditions.…”