Transcriptome Analysis of Salmonella Heidelberg after Exposure to Cetylpyridinium Chloride, Acidified Calcium Hypochlorite, and Peroxyacetic Acid

Abstract

The application of RNA sequencing in commercial poultry could facilitate a novel approach toward food safety with respect to identifying conditions in food production that mitigate transcription of genes associated with virulence and survivability. In this study, we evaluated the effects of disinfectant exposure on the transcriptomes of two field isolates of Salmonella Heidelberg (SH) isolated from a commercial broiler processing plant in 1992 and 2014. The isolates were each exposed separately to the following disinfectants commonly used in poultry processing: cetylpyridinium chloride (CPC), acidified calcium hypochlorite (aCH), and peroxyacetic acid (PAA). Exposure times were 8 s with CPC to simulate a poultry processing dipping station or 90 min with aCH and PAA to simulate the chiller tank in a poultry processing plant at 4°C. Based on comparison with a publicly available annotated SH reference genome with 5,088 genes, 90 genes were identified as associated with virulence, pathogenicity, and resistance (VPR). Of these 90 VPR genes, 9 (10.0%), 28 (31.1%), and 1 (1.1%) gene were upregulated in SH 2014 and 21 (23.3%), 26 (28.9%), and 2 (2.2%) genes were upregulated in SH 2014 challenged with CPC, aCH, and PAA, respectively. This information and previously reported MICs for the three disinfectants with both SH isolates allow researchers to make more accurate recommendations regarding control methods of SH and public health considerations related to SH in food production facilities where SH has been isolated. For example, the MICs revealed that aCH is ineffective for SH inhibition at regulatory levels allowed for poultry processing and that aCH was ineffective for inhibiting SH growth and caused an upregulation of VPR genes.

Cetylpyridinium Chloride: Mechanism of Action, Antimicrobial Efficacy in Biofilms, and Potential Risks of Resistance

“…Among the 90 genes associated with virulence, pathogenicity, and resistance (VPR) in wild-type S. Heidelberg, 10.0% (9 of 90 genes) or 23.3% (21 of 90 genes) of VPR genes were upregulated after exposure to CPC in 2014 and 1992 serovar S. Heidelberg field strains. They concluded that genes which can make multiple antibiotic-resistant proteins and multidrug-resistant proteins were mainly upregulated in CPCtreated S. Heidelberg (64).…”

Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016)

“…However, the mechanisms of transfer of disinfectant resistance genes remain unclear, and only a few have been described (Mc Carlie et al 2020). Cross-resistance between antimicrobial substances is becoming an increasing concern because of the possible positive correlation between resistance to disinfectants and resistance to antibiotics (Cadena et al 2019, Mc Carlie et al 2020. The major concern is based on the hypothesis that disinfectant exposure can promote antibiotic resistance, thus generating MDR bacteria (Mc Carlie et al 2020).…”

Non-Antibiotics Strategies to Control Salmonella Infection in Poultry

“…Another report evaluates the differential expression of genes in birds infected with Salmonella Typhimurium, finding genes related to the immune response, IgA production, activation of the Toll-like signaling receptor pathway, and cytokine-cytokine interactions [ 11 ]. Cadena and collaborators identify genes over-expressed in Salmonella Heidelberg when it is subjected to different disinfectants, finding some related to virulence, pathogenicity, and resistance, allowing with this identification to make recommendations for the control of Salmonella [ 199 ].…”