Occurrence of and in Cattle and Sheep in Northern Spain and Changes in Antimicrobial Resistance in Two Studies 10-years Apart

A cross-sectional survey was conducted in 2014-2016 in 301 ruminant herds to estimate and &nbsp;prevalence, and investigate their susceptibility to antimicrobials. Risk of shedding was higher in cattle than sheep (81.2% vs. 45.2%; OR = 5.22, < 0.001), whereas risk of shedding was higher in sheep than in cattle (19.1% vs. 11.3%; OR = 1.71, = 0.128). Susceptibility to six antimicrobials was determined by broth microdilution using European Committee for Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off values. exhibited higher resistance&nbsp;(94.1%, 32/34) than (65.1%, 71/109), and resistance was more widespread in isolates from dairy cattle than beef cattle or sheep. Compared to results obtained 10-years earlier (2003-2005) in a similar survey, an increase in fluoroquinolone-resistance was observed in from beef cattle (32.0% to 61.9%; OR = 3.45, = 0.020), and a decrease in tetracycline-resistance in from dairy cattle (75.0% to 43.2%; OR = 0.25, = 0.026). Resistance to macrolides remained stable at low rates and restricted to from dairy cattle, with all macrolide-resistant showing a pattern of pan-resistance. Presence of the single nucleotide polymorphisms (SNPs) associated to quinolone and macrolide resistance was confirmed in all phenotypically resistant isolates. The increase in fluoroquinolone resistance is worrisome but susceptibility to macrolides is reassuring.