Pasteurella Multocida are not Associated with its

Forty-eight Pasteurella multocida isolates were recovered from porcine pneumonic lungs 12 collected in Norwestern Spain (20172019). These isolates were characterized for their minimal 13 inhibition concentrations to twelve antimicrobial agents and for the appearance of eight resistance 14 genes: tetA, tetB, blaROB1, blaTEM, ermA, ermC , mphE and msrE. Relevant resistance percentages were 15 shown to teracyclines, sulphamethoxazole/trimethoprim and tiamulin, thus suggesting that P. 16 multocida isolates were mostly susceptible to amoxicillin, ceftiofur, enrofloxacin, florfenicol, 17 marbofloxacin and macrolides. 29.2% of isolates were resistant to more than two antimicrobials. 18 The tetracycline resistance genes (tetA and tetB) were detected in 22.9% of the isolates, but none was 19 positive to both simultaneously; blaROB1 and blaTEM genes were found in one third of isolates but both 20 genes were detected simultaneously in only one isolate. ermC gene was observed in 41.7% of 21 isolates, a percentage that decreased until 22.9% for msrE; finally, ermA was harboured by 16.7% 22 and mphE was not found in any of them. Six clusters were established based on hierarchical 23 clustering analysis on antimicrobial susceptibility for the twelve antimicrobials. Generally, it was 24 unable to foresee the antimicrobial susceptibility pattern for each family and the association of each 25 particular isolate inside the clusters established from the presence or absence of the resistance 26 genes analyzed. 27