Work

Prevalence of antimicrobial resistance in Campylobacter spp. and Salmonella spp. in Switzerland 2007–2022: a retrospective observational study

Year: 2026

Type: article

Abstract: BACKGROUND: In Switzerland, acute infectious diarrhoea is frequently caused by Campylobacter spp. and Salmonella spp. The rise of antimicrobial resistance complicates treatment and underscores requirements for continuous surveillance. We aimed to analyse the development of antimicrobial resistance in Campylobacter spp. and Salmonella spp. isolated from human samples in Switzerland over time. METHODS: We conducted a retrospective observational analysis using the ANRESIS database, covering the period from January 2007 to December 2022. The study included 47,498 Campylobacter spp. isolates and 5964 Salmonella enterica isolates. Antimicrobial resistance was categorised according to CLSI or EUCAST. Descriptive statistical analyses were performed to explore resistance over time, focusing on pathogens and invasive versus non-invasive isolates. RESULTS: The majority of Campylobacter isolates were Campylobacter jejuni (80.4%) and Campylobacter coli (7%). Resistance to ciprofloxacin in Campylobacter jejuni increased from 38% in 2007 to 81% in 2022. Resistance to doxycycline and tetracycline also rose sharply between 2012 and 2014, reaching approximately 37% by 2022. Resistance to macrolides remained consistently low (<1%) throughout the study period. Campylobacter coli exhibited higher resistance levels compared to Campylobacter jejuni, with notable increases in resistance to ciprofloxacin (73%) and macrolides (approximately 15%) by 2022. Non-typhoidal Salmonella accounted for 95.4% of all Salmonella isolates, with serovars Enteritidis (32%) and Typhimurium (15%) being most prevalent. Resistance to ciprofloxacin/norfloxacin was observed in about 10% of isolates, with an increase noted around 2013–2014. High resistance levels were found for amoxicillin/ampicillin (23%) and gentamicin (70%), while resistance to third- and fourth-generation cephalosporins and carbapenems remained low (<1%). A decline in nitrofurantoin resistance was also observed over time. CONCLUSIONS: The increasing prevalence of antimicrobial resistance in Campylobacter spp. and Salmonella spp. in Switzerland emphasises the critical need for ongoing surveillance and judicious antibiotic use.

Source: Swiss Medical Weekly

DOI: 10.57187/4615

Authors: Frederik Jung, Deborah R. Vogt, Roger Stephan, Andreas Kronenberg, Adrian Egli

Institutions: University of Zurich, University of Basel, University Hospital of Basel, University of Bern

Language: English

Topic: Salmonella and Campylobacter epidemiology

Subfield: Food Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: diamond

Funders: University of Bern, Bundesamt für Gesundheit