Carvacrol attenuates Campylobacter jejuni colonization factors and proteome critical for persistence in the chicken gut

Authors: WAGLE, BASANTA - UNIVERSITY OF ARKANSAS; Donoghue, Ann - Annie; SHRESTEA, SANDIP - UNIVERSITY OF ARKANSAS; UPADHYAYA, INDU - UNIVERSITY OF CONNECTICUT; ARSI, KOMALA - UNIVERSITY OF ARKANSAS; GUPTA, ANAMIKA - UNIVERSITY OF ARKANSAS; LIYANAGE, ROHANA - UNIVERSITY OF ARKANSAS; RATH, NARAYAN; DONOGHUE, DAN - UNIVERSITY OF ARKANSAS; UPADHYAY, ABHINAV - UNIVERSITY OF CONNECTICUT

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2020
Publication Date: 7/2/2020
Publication URL: https://handle.nal.usda.gov/10113/7007527
Citation: Wagle, B.R., Donoghue, A.M., Shrestea, S., Upadhyaya, I., Arsi, K., Gupta, A., Liyanage, R., Rath, N.C., Donoghue, D.J., Upadhyay, A. 2020. Carvacrol attenuates Campylobacter jejuni colonization factors and proteome critical for persistence in the chicken gut. Poultry Science. https://doi.org/10.1016/j.psj.2020.06.020.
DOI: https://doi.org/10.1016/j.psj.2020.06.020

Interpretive Summary: Campylobacter jejuni is a major foodborne pathogen that causes bacterial diarrheal illnesses in humans. Chickens are the reservoir host for C. jejuni, wherein the pathogen colonizes the intestine leading to contamination of carcasses during processing. The major colonization factors in C. jejuni include motility, intestinal epithelial attachment, acid/bile tolerance, and quorum sensing. Reducing the expression of the aforementioned factors could potentially reduce C. jejuni colonization in chickens. This study investigated the efficacy of sub-inhibitory concentration (SIC; compound concentration not inhibiting bacterial growth) of carvacrol in reducing the expression of C. jejuni colonization factors. Moreover, the effect of carvacrol on the expression of C. jejuni proteome was investigated using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The SIC (0.002%) of carvacrol reduced the motility of C. jejuni S-8 and NCTC 81-176 by ~50% and 35% respectively. Carvacrol inhibited C. jejuni S-8 and NCTC 81-176 adhesion to chicken enterocytes. Moreover, carvacrol reduced autoinducer-2 activity and increased the susceptibility of C. jejuni to acid and bile in both the strains. LC-MS/MS revealed that SIC of carvacrol reduced the expression of select C. jejuni colonization proteins critical for motility, adhesion, growth and metabolism, and anaerobic respiration. Results suggest the mechanisms by which carvacrol could reduce C. jejuni colonization in chickens.

Technical Abstract: Campylobacter jejuni is a major foodborne pathogen that causes gastroenteritis in humans. Chickens act as the reservoir host for C. jejuni, wherein the pathogen asymptomatically colonizes the ceca leading to contamination of carcasses during slaughter. The major colonization factors in C. jejuni include motility, intestinal epithelial attachment, acid/bile tolerance, and quorum sensing. Reducing the expression of the aforementioned factors could potentially reduce C. jejuni colonization in chickens. This study investigated the efficacy of sub-inhibitory concentration (SIC; compound concentration not inhibiting bacterial growth) of carvacrol in reducing the expression of C. jejuni colonization factors in vitro. Moreover, the effect of carvacrol on the expression of C. jejuni proteome was investigated using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The motility assay was conducted at 42°C, and the motility zone was measured after 24 h of incubation. For the adhesion assay, monolayers of primary chicken enterocytes (~105 cells/well) were inoculated with C. jejuni (6 Log CFU/well) either in the presence or absence of carvacrol and the adherent C. jejuni were enumerated after 90 min of incubation at 42°C. The effect of carvacrol on C. jejuni quorum sensing and susceptibility to acid/bile stress was investigated using a bioluminescence and an acid-bile survival assay, respectively. The SIC (0.002%) of carvacrol reduced the motility of C. jejuni S-8 and NCTC 81-176 by ~50% and 35%, respectively (P<0.05). Carvacrol inhibited C. jejuni S-8 and NCTC 81-176 adhesion to chicken enterocytes by ~0.8 and 1.5 Log CFU/mL, respectively (P<0.05). Moreover, carvacrol reduced autoinducer-2 activity and increased the susceptibility of C. jejuni to acid and bile in both the strains (P<0.05). LC-MS/MS revealed that SIC of carvacrol reduced the expression of select C. jejuni colonization proteins critical for motility (Methyl-accepting chemotaxis protein), adhesion (GroL), growth and metabolism (AspA, AcnB, Icd, Fba, Ppa, AnsA, Ldh, Eno, PurB-1), and anaerobic respiration (NapB, HydB, SdhA, NrfA) (P<0.05). Results suggest the mechanisms by which carvacrol could reduce C. jejuni colonization in chickens.