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Background/Objectives: Staphylococcus pseudintermedius is part of the normal microbiota in dogs. Since 2006, an increase in multidrug-resistant clones of methicillin-resistant S. pseudintermedius has been reported, as well as zoonotic transmission. Longitudinal investigations into clonal population structures, antibiotic resistance patterns, and the presence of resistance and virulence genes are important tools for gaining knowledge of the mechanisms behind the emergence of such clones. Methods: We investigated 87% of all non-repetitive MRSP isolates from dogs and cats in Sweden over a ten-year period (n = 356). All isolates were subjected to staphylococcal chromosomal cassette mec identification, whole-genome sequencing, multi-locus sequence typing, and analyses of genomic relatedness, as well as investigation of phenotypical resistance patterns and the presence of antibiotic resistance genes and virulence genes. Results: A considerable increase over time in the number of clonal lineages present was observed, indicating genomic diversification, and four clones became dominant: ST71, ST258, ST265, and ST551. In total, 96% of the isolates were multidrug-resistant. Statistically significant differences in resistance to several antibiotic classes between the four dominant clones were present. All isolates carried several virulence genes encoding factors associated with attachment, colonization, toxin synthesis, quorum sensing, antibiotic resistance, and immune evasion. [ABSTRACT FROM AUTHOR]

Background: Extended-spectrum cephalosporin-resistant Enterobacteriaceae (ESCRE) are an increasing healthcare problem in both human and veterinary medicine. The spread of ESCRE is complex with multiple reservoirs and different transmission routes. The aim of this study was to investigate if ESCRE carriage in dogs is more prevalent in households with a known human carrier, compared to households where humans are known to be negative for ESCRE. Identical ESCRE strains in humans and dogs of the same household would suggest a possible spread between humans and dogs. Methods: Twenty-two dog owners with a positive rectal culture for ESCRE each collected a rectal sample from their dog. In addition, a control group of 29 healthy dog owners with a documented negative rectal culture for ESCRE each sampled their household dog. Samples were cultivated for ESCRE using selective methods. In households where both humans and dogs carried ESCRE, isolates were further analysed for antimicrobial susceptibility by disc diffusion or microdilution and for genotype and genetic relatedness using molecular methods. Results: In 2 of 22 households studied, identical ESCRE strains with respect to bacterial species, antibiogram, genotype, and MLVA type were found in humans and dogs. The ESCRE found in the two households were ESBL-producing E. coli with the resistance gene blaCTX-M-27 and AmpC-producing E. coli with blaCMY-2, blaTEM-1. ESCRE were not found in dogs in the control group. Conclusions: In households where humans are carrying ESCRE, identical strains were to a limited extent found also in household dogs, indicating a transfer between humans and dogs. In contrast, ESCRE were not found in dogs in households without human carriers. [ABSTRACT FROM AUTHOR]

Sixteen endemic Hawaiian species of Lysimachia, formerly referred to as subgenus Lysimachiopsis, form a morphologically distinct and monophyletic group within the genus. This group has radiated in various habitats, and most species are endemic to a single island. To reconstruct phylogenetic interrelationships between the recognized taxa, we conducted phylogenetic analyses of 12 species of Lysimachia subgenus Lysimachiopsis using nuclear ribosomal DNA from two (ETS, ITS) and plastid DNA from five markers (rpl16, rpl20-rps12, rps16, trnH-psbA, trnS-G). A Bayesian analysis using all molecular data indicated that there are two major evolutionary lineages of Hawaiian endemic Lysimachia. The results also provide new insights into the evolutionary history of the problematic L. hillebrandii /L. remyi complex, showing that L. hillebrandii and L. waianaeensis are closely related but that L. ovoidea is more distantly related and belongs to the other major lineage. Furthermore, L. remyi subsp. remyi and subsp. subher bacea are both closely related to L. maxima, but L. remyi subsp. caliginis and subsp. kipahuluensis belong to the second major lineage. Our results also indicated that earlier taxonomic treatments of the group need to be partially revised to reflect evolutionary relationships. A brief discussion on biogeography of the group is presented. The new combinations Lysimachia kipahuluensis subsp. caliginis and Lysimachia remyi subsp. maxima are made. [ABSTRACT FROM AUTHOR]