Disinfectant and antimicrobial susceptibility profiles of Campylobacter coli isolated in 1998 to 1999 and 2015 from swine and commercial pork chops

Authors: Beier, Ross; Harvey, Roger; Hernandez, Charles; Andrews, Kathleen - Kate; Droleskey, Robert - Bob; Hume, Michael; DAVIDSON, MAUREEN - Us Food & Drug Administration (FDA); BODEIS-JONES, SONIA - Us Food & Drug Administration (FDA); YOUNG, SHENIA - Us Food & Drug Administration (FDA); Anderson, Robin; Nisbet, David

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2019
Publication Date: 6/1/2019
Publication URL: http://handle.nal.usda.gov/10113/6469761
Citation: Beier, R.C., Harvey, R.B., Hernandez Jr., C.A., Andrews, K., Droleskey, R.E., Hume, M.E., Davidson, M.K., Bodeis-Jones, S., Young, S., Anderson, R.C., Nisbet, D.J. 2019. Disinfectant and antimicrobial susceptibility profiles of Campylobacter coli isolated in 1998 to 1999 and 2015 from swine and commercial pork chops. Journal of Food Science. 84(6):1501-1512. https://doi.org/10.1111/1750-3841.14622.
DOI: https://doi.org/10.1111/1750-3841.14622

Interpretive Summary: Many different kinds of disinfectants are used in animal production, food processing plants, hospitals, and homes. In each of these places, there is also widespread use of a variety of antibiotics. Little is known about the impact of disinfectants on the spread of antibiotic resistance. In this study, we evaluated the disinfectant and antimicrobial susceptibility profiles of Campylobacter coli strains from market age pigs, sows, and retail pork chops. A low prevalence of antimicrobial resistance (AMR) was observed in the 111 C. coli strains to gentamicin 0%, ciprofloxacin 4%, nalidixic acid 4%, telithromycin 8%, clindamycin 13%, azithromycin 15%, erythromycin 15%, and florfenicol 0% resistance. However, tetracycline (TET) resistance was observed in 55.6% of the strains from swine cecal, fecal, and retail swabs and in 75% of the strains isolated from retail pork chops. The primary antibiotic resistance traits were TET followed by azithromycin-erythromycin-TET-telithromycin-clindamycin. There was no observed correlation between disinfectant resistance and antibiotic resistance. All strains were resistant to the disinfectant triclosan (a pseudo-antibiotic), and 99 out of 111 strains were resistant to chlorhexidine. All strains were susceptible to benzalkonium chloride. The disinfectants, Tek-Trol and providone-iodine, and the disinfectant components, tris(hydroxylmethyl)nitromethane (THN) and formaldehyde, demonstrated the highest susceptibilities. Didecyldimethylammonium chloride (C10AC) appeared to be about equally active as benzyldimethyltetradecylammonium chloride (C14BAC) for inhibiting C. coli, and both components were more active than C8AC and C12BAC, but C16BAC was not efficient at inhibiting C. coli. Several disinfectants are made up of an array of chemical components. The BACs, C12BAC and C14BAC, were the most active ingredients in the disinfectant DC&R. Also, C12BAC and C14BAC, or these two components and C10AC in synergy were responsible for inhibition of C. coli at high minimum inhibitory concentrations (MICs) against the disinfectant P-128. All manufacturer recommended application levels were above the observed MICs. However, observed MICs for Tek-Trol were close to the suggested application rates, and a small dilution error could easily render this disinfect non-functional.

Technical Abstract: The disinfectant and antimicrobial susceptibility profiles were determined for 111 Campylobacter coli strains obtained from market age pigs, sows, and retail pork chops. A low prevalence of antimicrobial resistance (AMR) was observed, but tetracycline (TET) resistance was observed in swine cecal, fecal, and rectal swab strains (55.6%) and retail pork chops (75%). The primary antibiotic resistance traits were TET followed by azithromycin-erythromycin-TET-telithromycin-clindamycin. All strains were resistant to the disinfectant, triclosan (a pseudo-antibiotic), and 99/111 strains were resistant to chlorhexidine. All strains were susceptible to benzalkonium chloride. The disinfectants, Tek-Trol and providone-iodine, and the disinfectant components, tris(hydroxylmethyl)nitromethane (THN) and formaldehyde, demonstrated the highest susceptibilities. Didecyldimethylammonium chloride (C10AC) appeared to be about equally active as benzyldimethyltetradecylammonium chloride (C14BAC) for inhibiting C. coli, and both components were more active than C8AC and C12BAC, but C16BAC was not efficient at inhibiting C. coli. The BACs, C12BAC and C14BAC, were the most active ingredients in the disinfectant DC&R. Also, C12BAC and C14BAC, or these two components and C10AC in synergy, were responsible for inhibition of C. coli at high minimum inhibitory concentrations (MICs) against the disinfectant P-128. No cross-resistance between antibiotics and disinfectants was observed. All manufacturer recommended application levels were above the observed MICs. However, observed MICs for Tek-Trol were close to the suggested application rates, and a small dilution error could easily render this disinfect non-functional. The continued use of THN and formaldehyde in DC&R is questionable because these components are not effective, and their inclusion results only in additional unwanted chemicals in the environment.