The primary objective of this study was to explore the variability of Streptococcus uberis (S. uberis) isolates by extracting multilocus sequence typing (MLST) data from whole-genome sequencing. The secondary objective was to determine the distribution of the phenotypic antimicrobial resistance (AMR) and the associated AMR genes as well as the virulence gene profiles among sequence types (STs). Sixty-two isolates were recovered from 16 herds in 3 Canadian Maritime Provinces: New Brunswick (14.5%), Nova Scotia (48.3%), and Prince Edward Island (37.1%). Of these, 9, 30, and 23 were recovered from post-calving, lactational samples, and post-mastitis samples, respectively. These 62 S. uberis isolates belonged to 34 STs; 11 isolates were typed to 9 known STs and 51 isolates were classified as one of 25 new STs. Thirteen isolates were part of major clonal complexes (CCs). Post-mastitis isolates contained 10 unique STs, lactational isolates contained 11 unique STs, and post-calving isolates had 3 STs. Each farm had only 1 isolate that was a unique ST except for STs 233, 851, 855, 857, 864, and 866, which were found in multiple cows per herd on more than one farm. ST851 and ST857 were found in each of the 3 sample types, with ST857 found in cows from all 3 Maritime provinces. These results indicate that S. uberis is a diverse non-clonal pathogen with specific STs residing in clonal clusters, carrying multiple AMR genes and virulence, with a diverse phenotypic AMR.

Hemorrhagic pneumonia in mink is a fatal disease caused by Pseudomonas aeruginosa. Very little is known about P. aeruginosa in relation to genotype and the mechanisms underlying antimicrobial resistance in mink. A total of 110 P. aeruginosa samples were collected from mink from Chinese mink farms between 2007 and 2015. Samples underwent molecular genotyping using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), antimicrobial susceptibility and its mechanism were investigated at the molecular level. The PFGE identified 73 unique types and 15 clusters, while MLST identified 43 (7 new) sequence types (ST) and 12 sequence type clonal complexes (STCC). Sequence types and PFGE showed persistence of endemic clones in cities Wendeng (Shandong, China) and Dalian (Liaoning, China), even in different timelines. The MLST also revealed the gene correlation of the mink P. aeruginosa across different time and place. The ST1058 (n = 14), ST882 (n = 11), and ST2442 (n = 10) were the predominant types, among which ST1058 was the only one found both in Shandong province and Dalian (Liaoning, China). The MLST for P. aeruginosa infection in mink was highly associated with that in humans and other animals, implying possible transmission events. A small proportion of mink exhibited drug resistance to P. aeruginosa (9/69, 13%) with resistance predominantly to fluoroquinolone, aminoglycoside, and β-lactamase. Eight strains had mutations in the quinolone-resistance determining regions (QRDR). High proportions (65%; 72/110) of the fosA gene and 2 types of glpt deletion for fosmycin were detected. Furthermore, in the whole genome sequence of one multidrug resistant strain, we identified 27 genes that conferred resistance to 14 types of drugs.