Biofilm-forming ability of Salmonella enterica strains of different serotypes isolated from multiple sources in China.

Salmonella is an important zoonotic and foodborne pathogen that can infect humans and animals, causing severe concerns about food safety and a heavy financial burden worldwide. The pathogen can adhere to living and abiotic surfaces by forming biofilms, which increases the risk of transmission and infection. In this study, we investigated the biofilm-forming ability of 243 Salmonella strains of 36 serotypes from different sources in China using microplate crystal violet staining method. The results showed that 99.6% tested strains, with the exception of one strain of S. Thompson, were capable of forming biofilms. The strains with the biofilm-forming ability of strong, medium and weak accounted for 2.88%, 24.28% and 72.43%, respectively. The strains of S. Havana and S. Hvittingfoss had the strongest biofilm-forming ability, with the OD of 0.81 ± 0.02 and 0.81 ± 0.38, respectively, while the strains of S. Agona and S. Bovismorbificans had the weakest biofilm-forming ability, with the OD of 0.16 ± 0.02 and 0.15 ± 0.00, respectively. Furthermore, statistical analysis results demonstrated that isolation of source had no effect on the biofilm formation ability, while the detection rates of pefABCD and ddhC were positively correlated with the biofilm formation ability of Salmonella. In particular, the detection rate of ddhC gene was more than 60% in the biofilm forming strains. These findings have important guiding significance for the investigation of pathogenesis, as well as the prevention and control of salmonellosis.