# Pan-European analysis shows stable, low antimicrobial resistance in most bovine and porcine respiratory tract pathogens

## TL;DR

A study across eight European countries found that most bacteria causing respiratory infections in cattle and pigs showed low and stable antibiotic resistance, except for tetracycline.

## Contribution

The study provides a pan-European comparison of antimicrobial resistance in bovine and porcine respiratory pathogens over time.

## Key findings

- Low resistance to most antibiotics was observed in bovine and porcine respiratory tract pathogens.
- Tetracycline resistance was notably higher compared to other antibiotics.
- Multidrug resistance remained low across all tested pathogens.

## Abstract

To survey antibiotic susceptibility of bacteria causing bovine and porcine respiratory tract infections in eight European countries and to compare retrospectively the resistance percentages between the countries participating in the VetPath programs.

Non-replicate nasopharyngeal/nasal or lung swabs were collected by harmonized sampling from animals with acute respiratory signs during the period 2019–2020. Pasteurella multocida, Mannheimia haemolytica, Histophilus somni from cattle (n = 307), and P. multocida, Actinobacillus pleuropneumoniae, Glaesserella parasuis, Bordetella bronchiseptica and Streptococcus suis from pigs (n = 659) were isolated by standard methods. S. suis was also isolated from meningitis cases. Minimum Inhibitory Concentrations (MICs) were assessed following CLSI standards and interpreted using veterinary breakpoints where available. H. somni isolates were fully susceptible against all tested antibiotics. Resistance in bovine P. multocida and M. haemolytica was absent or low, except for tetracycline (29.7 and 19.6% resistance for the two bacteria, respectively). Low macrolide and spectinomycin resistance were observed for M. haemolytica (1.5–2.3%) contrary to P. multocida (8.3–22.1%). Similar susceptibility patterns were observed in pigs. Resistance in P. multocida, A. pleuropneumoniae and S. suis to ceftiofur, enrofloxacin, florfenicol, and penicillin was absent or <3.0%. Tetracycline resistance varied from 11.4 to 13.9% but was 83.2% in S. suis. For all pathogens multidrug-resistance was low (0–6.2%). Overall, antibiotic resistance in the 2019–2020 survey remained similar as in the 2009–2012 and 2015–2016 surveys. Among the countries significant variations of resistance levels were observed, particularly for tetracycline. Drivers behind these country differences remain unclear.

With the exception of tetracycline, low antibiotic resistance was observed among major bovine and porcine respiratory tract pathogens in Europe.