Antimicrobial Resistance in Isolates from Cattle with Bovine Respiratory Disease in Bavaria, Germany

Abstract

Patterns of antimicrobial resistance (AMR) regarding Pasteurella multocida (n = 345), Mannheimia haemolytica (n = 273), Truperella pyogenes (n = 119), and Bibersteinia trehalosi (n = 17) isolated from calves, cattle and dairy cows with putative bovine respiratory disease syndrome were determined. The aim of this study was to investigate temporal trends in AMR and the influence of epidemiological parameters for the geographic origin in Bavaria, Germany, between July 2015 and June 2020. Spectinomycin was the only antimicrobial agent with a significant decrease regarding not susceptible isolates within the study period (P. multocida 88.89% to 67.82%, M. haemolytica 90.24% to 68.00%). Regarding P. multocida, significant increasing rates of not susceptible isolates were found for the antimicrobials tulathromycin (5.56% to 26.44%) and tetracycline (18.52% to 57.47%). The proportions of multidrug-resistant (MDR) P. multocida isolates (n = 48) increased significantly from 3.70% to 22.90%. The proportions of MDR M. haemolytica and P. multocida isolates (n = 62) were significantly higher in fattening farms (14.92%) compared to dairy farms (3.29%) and also significantly higher on farms with more than 300 animals (19.49%) compared to farms with 100 animals or less (6.92%). The data underline the importance of the epidemiological farm characteristics, here farm type and herd size regarding the investigation of AMR.

Keywords: Mannheimia haemolytica; Pasteurella multocida; Truperella pyogenes; antimicrobial resistance; bovine respiratory disease; dairy farm; multidrug-resistance.

Figure 1

Overall proportion (%) of pathogens detected among the total number of analyzed samples.

Figure 2

Statistically significant trends regarding the not susceptibility of P. multocida (a) and M. haemolytica (b) over the five-year period in Bavaria, Germany. For spectinomycin a significant decrease in not susceptibility could be observed in P. multocida (OR = 0.70; 95% CI: 0.56–0.86; p < 0.001) (a) and in M. haemolytica isolates (OR = 0.71; 95% CI: 0.55–0.90; p = 0.005) (b). For tetracycline (OR = 1.62; 95% CI: 1.36–1.94; p < 0.001) and tulathromycin (OR = 1.60; 95% CI: 1.25–2.08; p < 0.001) a significant increase in not susceptible P. multocida isolates could be observed (a).

Figure 3

Annual multidrug-resistance (MDR) rates of the bacterial pathogens P. multocida and M. haemolytica from cattle with bovine respiratory disease (BRD) in Bavaria, Germany. A significant increase of MDR P. multocida isolates could be observed over the five-year period 2015–2020 (OR = 1.61; 95% CI: 1.25–2.14; p < 0.001).

Figure 4

Proportion of multidrug-resistant (MDR) P. multocida and M. haemolytica isolates depending on farm size (number of animals per farm) (a) and type of farm (b). In farms with more than 300 animals, the odds for isolating MDR isolates were significantly higher than in farms with 100 or less animals (Adjusted OR = 2.89; 95% CI: 1.26–7.29; p = 0.017). In addition, the odds for isolating MDR isolates were significantly lower in dairy (aOR = 0.23; 95% CI: 0.08–0.54; p = 0.002) and mixed farms (aOR = 0.46; 95% CI: 0.20–0.93; p = 0.042) than in fattening farms.