Fig 1.
Graphical representation of the fecal sampling scheme in all of the animal categories evaluated, including the numbers of animals sampled in the cross-sectional study (S1).
Fig 2.
Graphical representation of the fecal sampling scheme in the longitudinal study (S2), focusing specifically on animals in the peripartum period.
Fig 3.
A—Distribution of Salmonella sp. and S. Dublin among the different categories of the studied herd. B—Distribution of the different serotypes of Salmonella among the categories of the studied herd.
Fig 4.
A—Prevalence of Salmonella spp. shedding during the peripartum period in multiparous and primiparous cows. B–Distribution of different Salmonella serotypes among the animals studied.
Fig 5.
Prevalence of S. Dublin shedding and other serotypes during the prepartum, parturition, and postpartum periods.
Fig 6.
Necropsies of calves aged between 91 and 150 days in whom Salmonella sp. were isolated.
A) Lung with severe edema, pronounced jaundice, and diffuse petechiae. B) Intestine with diffuse petechiae along the serosa, with areas of suffusion in the serosa. C) Enlarged liver with irregular coloring and rounded edges. D) Kidney with an irregular surface and diffuse petechiae throughout the surface.
Fig 7.
Antimicrobial resistance profile of S. Dublin samples isolated from healthy cattle (A, fecal shedding: n = 10; vaginal secretion: n = 3; colostrum n = 1) and from animals subjected to post-mortem examination (B, infected animals) on a dairy farm. AM = ampicillin/penicillins; C = chloramphenicol/phenicols; TE = tetracyclines; GM = gentamicin; CIP = ciprofloxacin/fluoroquinolone; CF = cephalosporins; SXT = sulfamethoxazole + trimethoprim; CL = colistin; AMC = amoxicillin + clavulanic acid; AN = amikacin; FM = nitrofurantoin; AZM = azithromycin; CRO = ceftriaxone; FOS = fosfomycin; MEM = meropenem.
Fig 8.
Resistance genes and plasmids found in the S. Dublin sequenced strains.
Fig 9.
The phylogenetic tree of single nucleotide polymorphisms (SNPs) found in the genome of seven S. Dublin isolates obtained from healthy cattle or diagnosed with clinical salmonellosis (marked in gray).
S. Dublin isolates from previous studies in Brazil [12] were included for comparison. The colored dots indicate the presence of resistance genes to different classes of antimicrobials, while the red and blue colors indicate the type of host of the isolate (bovine and human, respectively).