Effect of low concentrations of lactic acid and temperature on the expression of adhesion, invasion, and toxin-encoding genes of Campylobacter jejuni from poultry

The consumption of contaminated poultry meat is considered as a significant route of campy- lobacteriosis transmission. Lactic acid is a disinfectant agent with bactericidal effects on Campylobacter spp. The purpose of this study was to assess the low concentrations of lactic acid effect and different temperatures on the transcriptomic responses of Campylobacter jejuni (C. jejuni) adhesion and virulence-associated genes including peb4, ciaB, cdtA, cdtB, and cdtC.

The samples were incubated at 10°C and 22°C for 48 h upon exposure to 30% and 60% lactic acid. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of lactic acid was also determined. Then, gene expression was assessed using real-time polymerase chain reaction (RT-PCR).

Lactic acid had lower MIC and MBC levels at lower temperature. The utilization of both levels of lactic acid signifi- cantly reduced the expression of peb4, ciaB, cdtB, and cdtC genes over 48 h of incubation at 22°C. However, no significant difference was found in the expression of the cdtA gene between 10 and 22°C at 30% lactic acid.

These results highlight the potential of low-concentration lactic acid in the downregulation of adhesion and virulence-associated genes as well as reduction of C. jejuni pathogenicity.