As a primary source of Shiga-toxin-producing Escherichia coli (STEC) infection, cattle are often targeted to develop strategies for reducing STEC contamination. Monitoring the virulence potentials of STEC isolates from cattle is important for tracing contamination sources, managing outbreaks or sporadic cases, and reducing the risks for human infection. This study aimed to investigate the prevalence of STEC in cattle farm samples in South Korea and to assess their virulence potentials. In total, 63 STEC were isolated from 496 cattle farm samples, and temperature and rainfall affected STEC prevalence (p < 0.001). The O157 serogroup was most prevalent, followed by O108, O8, O84, O15, and O119. In the stx variant test, high prevalence of stx2a and stx2c (known to be associated with high STEC virulence) were observed, and stx2g, a bovine STEC variant, was detected in STEC O15 and O109. Additionally, stx1c was detected in eae-positive STEC, suggesting genetic dynamics among the virulence genes in the STEC isolates. STEC non-O157 strains were resistant to tetracycline (17.9%), ampicillin (14.3%), and cefotaxime (3.6%), while STEC O157 was susceptible to all tested antimicrobials, except cefotaxime. The antimicrobial resistance genes, bla TEM (17.5%), tetB (6.3%), and tetC (4.8%), were only detected in STEC non-O157, whereas tetE (54.0%) was detected in STEC O157. AmpC was detected in all STEC isolates. Clustering was performed based on the virulence gene profiles, which grouped STEC O84, O108, O111, and O157 together as potentially pathogenic STEC strains. Finally, PFGE suggested the presence of a prototype STEC that continues to evolve by genetic mutation and causes within- and between-farm transmission within the Gyeonggi province. Considerable numbers of STEC non-O157 were isolated from cattle farms, and the virulence and antimicrobial resistance features were different between the STEC O157 and non-O157 strains. STEC from cattle with virulence or antimicrobial resistance genes might represent a threat to public health and therefore, continual surveillance of both STEC O157 and non-O157 would be beneficial for controlling and preventing STEC-related illness.

The worldwide spread of extended spectrum β-lactamase (ESBL)- and AmpC β-lactamase (AmpC)-producing Escherichia coli poses serious threats to public health. Swine farms have been regarded as important reservoirs of ESBL/AmpC-EC. This study aimed to determine the prevalence, ESBL/AmpC types, and clonal distribution of ESBL/AmpC-EC from swine farms and analyze the difference according to the swine production stages. In addition, we evaluated the potential risks of swine ESBL/AmpC-EC clones to humans. Individual fecal samples (n = 292) were collected from weaning, growing, finishing, and pregnant pigs in nine swine farms of South Korea between July 2017 and March 2020. In total, 161 ESBL/AmpC-EC isolates were identified (55.1%), with the highest prevalence detected in the weaning stage (86.3%). The dominant ESBL and AmpC types were CTX-M-55 (69.6%) and CMY-2 (4.3%), respectively. CTX-M found in all production stages, while CMY was only found in growing and finishing stages. In the conjugation assay, the high transferability of CTX-M gene (55.8%) was identified, while the transfer of CMY gene was not identified. The major clonal complexes (CCs) were CC101-B1 (26.8%), CC10-A (8.7%), and CC648-F (2.9%). There was similarity in clonal distribution between different swine production stages within swine farms, estimated using the k-means analysis, which suggested a clonal transmission between the different swine stages. Among swine ESBL/AmpC-EC sequence types (STs), seven STs (ST101, ST10, ST648, ST457, ST410, ST617, and ST744) were common with the human ESBL/AmpC-EC, which registered in National Center for Biotechnology Information database. The clonal population structure analysis based on the virulence factor (VF) presented that swine ESBL/AmpC-EC clones, especially ST101-B1, harbored a highly virulent profile. In conclusion, ESBL/AmpC-EC was distributed throughout the swine production stages, with the highest prevalence in the weaning stage. The CTX-M was present in all stages, while CMY was mostly found in growing-finishing stages. The swine ESBL/AmpC-EC was identified to harbor shared clone types with human ESBL/AmpC-EC and a virulent profile posing potential risk to humans. Considering the possibility of genetic and clonal distribution of ESBL/AmpC-EC among swine production stages, this study suggests the need for strategies considering the production system to control the prevalence of ESBL/AmpC-EC in swine farms.

In Korea, there is a need for research on human–animal relationships because of an increase in the number of companion animals and the positive changes in public perception toward them. Few studies have examined these changes. This epidemiological study investigates the characteristics of Korean dog owners and their pet dogs and identifies the owner- and dog-dependent factors that influence the owners' attitudes toward pets. We conducted a cross-sectional study of dog owners by asking them to complete a Pet Attitude Scale-based questionnaire about their dogs and themselves. The participants included 654 young adults between 19 and 39 years of age who lived in Seoul and owned dogs. We found that most dogs were owned by single, educated, high-income men who preferred small purebred dogs. Most were also likely to underestimate their dog's body condition score (BCS). The multivariable logistic regression (odds ratio, OR) and the multiple linear regression (unstandardized coefficients, B) models suggested that positive pet attitudes were associated with nine factors: overweight (OR = 2.68, B = 5.28) or a normal BCS (OR = 2.09, B = 5.58), having a medical history of related diseases (OR = 2.36, B = 6.38) and vaccination (OR = 2.10, B = 6.22), buying the pet dog (OR = 0.60, B = −3.85), having a small dog (≤10 kg) (OR = 1.66), visiting the veterinarian frequently (OR = 1.08, B = 0.39), spending more time with the dog (OR = 1.23, B =1.32), and keeping other species in the house (B = −4.27). This study is the first to identify the relationships between owner- and dog-dependent factors and pet owner attitude toward pets, all within a Korean cultural context. This study highlights the factors associated with the development of relationships between pet dogs and their owners. The exploratory study is novel because it examines pet ownership in the context of the Korean culture; previous pet ownership studies were set in the West and are analyzed with Western cultural values in mind.

Highly pathogenic avian influenza (HPAI), a zoonotic disease, is a major threat to humans and poultry health worldwide. In January 2014, HPAI virus subtype H5N8 first infected poultry farms in South Korea, and 393 outbreaks, overall, were reported with enormous economic damage in the poultry industry. We analyzed the spatiotemporal distribution of HPAI H5N8 outbreaks in poultry farms using the global and local spatiotemporal interaction analyses in the first (January to July 2014) and second (September 2014 to June 2015) outbreak waves. The space–time K-function analyses revealed significant interactions within three days and in an over-40 km space–time window between the two study periods. The excess risk attributable value (D₀) was maintained despite the distance in the case of HPAI H5N8 in South Korea. Eleven spatiotemporal clusters were identified, and the results showed that the HPAI introduction was from the southwestern region, and spread to the middle region, in South Korea. This spatiotemporal interaction indicates that the HPAI epidemic in South Korea was mostly characterized by short period transmission, regardless of the distance. This finding supports strict control strategies such as preemptive depopulation, and poultry movement tracking. Further studies are needed to understand HPAI disease transmission patterns.

Background: Various health benefits from the ownership of companion dogs have been studied from a One Health perspective. However, the preventive effects on depression are unclear, with inconsistent results across studies. We hypothesized that heterogeneity among owners would be related to the mixed results. Specifically, the difference in the strength of the bond between the owners and their companion dogs would modify the effect of dog ownership. As an exploratory study, we compared the depression symptoms of the owners with favorable attitudes toward their dogs, with those of the owners with unfavorable attitudes, to investigate the potential effect modification of owners’ attitudes on the association between the ownership and depression symptom. Methods: We conducted a web-based questionnaire survey of 654 19- to 39-year-old adults who had companion dogs in Seoul, South Korea, where a major health burden is depression among young adults. We measured the owners’ attitudes toward their dogs using the modified Pet Attitude Scale (PAS-M) and their depression symptoms using the short version of the Center for Epidemiologic Studies depression scale (CESD-10). Demographic and socioeconomic factors were measured to adjust for the association between attitude and depression symptoms. Multivariate logistic regression models were used in this study. Results: The owners who had less favorable attitudes toward their dogs (lower PAS-M scores) tended to have depression symptoms. The direction and significance were maintained either when the PAS-M variable was used as a continuous variable (odds ratio (OR) for one score increase in PAS-M was 0.95 (95% confidence interval (CI) = 0.94–0.96)) or as a categorical variable (OR for lower PAS-M was 3.19 (95% CI = 2.28 –4.47)). Conclusion: We found a positive significant association between owners’ depression symptoms and unfavorable attitudes toward their dogs, although causal direction could not be determined. Future studies should investigate the potential causal link.