Clinical herd health, farm management and antimicrobial resistance in Campylobacter coli on finishing pig farms in Switzerland M.E. Schuppers a , R. Stephan b , U. Ledergerber c , J. Danuser c , B. Bissig-Choisat c , K.D.C. Sta ¨rk c , G. Regula c, * a Safe Food Solutions Inc., Bremgartenstrasse 109A, CH-3012 Bern, Switzerland b Institute for Food Safety and Hygiene, University of Zu ¨rich, Winterthurerstrasse 272, CH-8057 Zu ¨rich, Switzerland c Swiss Federal Veterinary Office, Schwarzenburgstrasse 161, CH-3003 Bern, Switzerland Received 30 March 2004; received in revised form 23 December 2004; accepted 7 February 2005 Abstract The world-wide increase of antimicrobial resistance in micro-organisms complicates medical treatment of infected humans. We did a risk-factor analysis for the prevalence of antimicrobial resistant Campylobacter coli on 64 Swiss pig finishing farms. Between May and November 2001, 20 faecal samples per farm were collected from the floor of pens holding finishing pigs shortly before slaughter. Samples were pooled and cultured for Campylobacter species. Isolated Campylobacter strains were tested for resistance against selected antimicrobials. Additionally, information on herd health and management aspects was available from another study. Because data quality on the history of antimicrobial use on the farms was poor, only non-antimicrobial risk factors could be analysed. Statistical analyses were performed for resistance against ciprofloxacin, erythromycin, streptomycin, tetracycline, and for multiple resistance, which was defined as resistance to three or more antimicrobials. Risk factors for these outcomes – corrected for dependency of samples at herd level – were analysed in five generalised estimation-equation models. Prevalence of antimicrobial resistance among Campylobacter isolates was ciprofloxacin 26.1%, erythromycin 19.2%, strepto- mycin 78.0%, tetracycline 9.4%, and multiple resistance 6.5%. Important risk factors contributing to the prevalence of resistant strains were shortened tails, lameness, skin lesions, feed without whey, and ad libitum feeding. Multiple resistance was more likely in farms which only partially used an all-in- www.elsevier.com/locate/prevetmed Preventive Veterinary Medicine 69 (2005) 189–202 * Corresponding author. Tel.: +41 31 323 59 02; fax: +41 31 323 95 43. E-mail address: gertraud.regula@bvet.admin.ch (G. Regula). 0167-5877/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.prevetmed.2005.02.004