Publications by authors named "Younjung Kim"

9 Publications

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Dysbiosis of the Urinary Bladder Microbiome in Cats with Chronic Kidney Disease.

mSystems 2021 Aug 27;6(4):e0051021. Epub 2021 Jul 27.

Centre for Companion Animal Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Konggrid.35030.35, Hong Kong SAR.

Although feline urinary tract diseases cause high morbidity and mortality rates, and subclinical bacteriuria is not uncommon, the feline urinary microbiome has not been characterized. We conducted a case-control study to identify the feline urinary bladder microbiome and assess its association with chronic kidney disease (CKD), feline idiopathic cystitis (FIC), and positive urine cultures (PUCs). Of 108 feline urine samples subjected to 16S rRNA gene sequencing, 48 (44.4%) samples reached the 500-sequence rarefaction threshold and were selected for further analysis, suggesting that the feline bladder microbiome is typically sparse. Selected samples included 17 CKD, 9 FIC, 8 PUC cases and 14 controls. Among these, 19 phyla, 145 families, and 218 genera were identified. were the most abundant, followed by . Notably, four major urotypes were identified, including two urotypes predominated by Escherichia or and two others characterized by relatively high alpha diversity, Diverse 1 and Diverse 2. Urotype was associated with disease status ( value of 0.040), with the Escherichia-predominant urotype being present in 53% of CKD cases and in all of the Escherichia coli PUC cases. Reflecting these patterns, the overall microbial composition of CKD cases was more similar to that of E. coli PUC cases than to that of controls ( value of <0.001). Finally, PUC cases had microbial compositions distinct from those of controls as well as CKD and FIC cases, with significantly lower Shannon diversity and Faith's phylogenetic diversity values. Despite the clinical importance of urinary diseases in cats, the presence of resident urine microbes has not been demonstrated in cats, and the role of these microbes as a community in urinary health remains unknown. Here, we have shown that cats with and without urinary tract disease harbor unique microbial communities in their urine. We found no evidence to suggest that the bladder microbiome is implicated in the pathogenesis of feline idiopathic cystitis, a disease similar to bladder pain syndrome/interstitial cystitis in humans. However, cats with chronic kidney disease had dysbiosis of their bladder microbiome, which was predominated by Escherichia and had a community structure similar to that of cats with Escherichia coli cystitis. These findings suggest that chronic kidney disease alters the bladder environment to favor Escherichia colonization, potentially increasing the risk of overt clinical infection.
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http://dx.doi.org/10.1128/mSystems.00510-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8407359PMC
August 2021

Transmission Dynamics of African Swine Fever Virus, South Korea, 2019.

Emerg Infect Dis 2021 07;27(7):1909-1918

African swine fever (ASF) is a substantial concern for global food production and security. However, lack of epidemiologic data in affected areas has limited the knowledge of the main drivers of ASF virus (ASFV) transmission. To assess the role of vehicle movements and wild boar populations in spreading ASFV to pig farms in South Korea, we combined data generated by ASF surveillance on pig farms and of wild boars with nationwide global positioning system-based tracking data for vehicles involved in farming activities. Vehicle movements from infected premises were associated with a higher probability of ASFV incursion into a farm than was geographic proximity to ASFV-infected wild boar populations. Although ASFV can spill over from infected wild boars into domestic pigs, vehicles played a substantial role in spreading infection between farms, despite rapid on-farm detection and culling. This finding highlights the need for interventions targeting farm-to-farm and wildlife-to-farm interfaces.
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http://dx.doi.org/10.3201/eid2707.204230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237864PMC
July 2021

The role of livestock movements in the spread of Rift Valley fever virus in animals and humans in Mayotte, 2018-19.

PLoS Negl Trop Dis 2021 03 8;15(3):e0009202. Epub 2021 Mar 8.

Veterinary Epidemiology, Economics and Public Health group, Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hatfield, United Kingdom.

Rift Valley fever (RVF) is a vector-borne viral disease of major animal and public health importance. In 2018-19, it caused an epidemic in both livestock and human populations of the island of Mayotte. Using Bayesian modelling approaches, we assessed the spatio-temporal pattern of RVF virus (RVFV) infection in livestock and human populations across the island, and factors shaping it. First, we assessed if (i) livestock movements, (ii) spatial proximity from communes with infected animals, and (iii) livestock density were associated with the temporal sequence of RVFV introduction into Mayotte communes' livestock populations. Second, we assessed whether the rate of human infection was associated with (a) spatial proximity from and (b) livestock density of communes with infected animals. Our analyses showed that the temporal sequence of RVFV introduction into communes' livestock populations was associated with livestock movements and spatial proximity from communes with infected animals, with livestock movements being associated with the best model fit. Moreover, the pattern of human cases was associated with their spatial proximity from communes with infected animals, with the risk of human infection sharply increasing if livestock in the same or close communes were infected. This study highlights the importance of understanding livestock movement networks in informing the design of risk-based RVF surveillance programs.
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http://dx.doi.org/10.1371/journal.pntd.0009202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939299PMC
March 2021

Antibiotic resistance gene sharing networks and the effect of dietary nutritional content on the canine and feline gut resistome.

Anim Microbiome 2020 Feb 7;2(1). Epub 2020 Feb 7.

Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, China.

Background: As one of the most densely populated microbial communities on Earth, the gut microbiota serves as an important reservoir of antibiotic resistance genes (ARGs), referred to as the gut resistome. Here, we investigated the association of dietary nutritional content with gut ARG diversity and composition, using publicly available shotgun metagenomic sequence data generated from canine and feline fecal samples. Also, based on network theory, we explored ARG-sharing patterns between gut bacterial genera by identifying the linkage structure between metagenomic assemblies and their functional genes obtained from the same data.

Results: In both canine and feline gut microbiota, an increase in protein and a reduction in carbohydrate in the diet were associated with increased ARG diversity. ARG diversity of the canine gut microbiota also increased, but less strongly, after a reduction in protein and an increase in carbohydrate in the diet. The association between ARG and taxonomic composition suggests that diet-induced changes in the gut microbiota may be responsible for changes in ARG composition, supporting the links between protein metabolism and antibiotic resistance in gut microbes. In the analysis of the ARG-sharing patterns, 22 ARGs were shared among 46 genera in the canine gut microbiota, and 11 ARGs among 28 genera in the feline gut microbiota. Of these ARGs, the tetracycline resistance gene tet(W) was shared among the largest number of genera, predominantly among Firmicutes genera. Bifidobacterium, a genus extensively used in the fermentation of dairy products and as probiotics, shared tet(W) with a wide variety of other genera. Finally, genera from the same phylum were more likely to share ARGs than with those from different phyla.

Conclusions: Our findings show that dietary nutritional content, especially protein content, is associated with the gut resistome and suggest future research to explore the impact of dietary intervention on the development of antibiotic resistance in clinically-relevant gut microbes. Our network analysis also reveals that the genetic composition of bacteria acts as an important barrier to the horizontal transfer of ARGs. By capturing the underlying gene-sharing relationships between different bacterial taxa from metagenomes, our network approach improves our understanding of horizontal gene transfer dynamics.
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http://dx.doi.org/10.1186/s42523-020-0022-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7807453PMC
February 2020

Prevalence of Avian Influenza A(H5) and A(H9) Viruses in Live Bird Markets, Bangladesh.

Emerg Infect Dis 2018 12;24(12):2309-2316

We conducted a cross-sectional study in live bird markets (LBMs) in Dhaka and Chittagong, Bangladesh, to estimate the prevalence of avian influenza A(H5) and A(H9) viruses in different types of poultry and environmental areas by using Bayesian hierarchical logistic regression models. We detected these viruses in nearly all LBMs. Prevalence of A(H5) virus was higher in waterfowl than in chickens, whereas prevalence of A(H9) virus was higher in chickens than in waterfowl and, among chicken types, in industrial broilers than in cross-breeds and indigenous breeds. LBMs with >1 wholesaler were more frequently contaminated by A(H5) virus than retail-only LBMs. Prevalence of A(H9) virus in poultry and level of environmental contamination were also higher in LBMs with >1 wholesaler. We found a high level of circulation of both avian influenza viruses in surveyed LBMs. Prevalence was influenced by type of poultry, environmental site, and trading.
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http://dx.doi.org/10.3201/eid2412.180879DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6256373PMC
December 2018

Livestock trade network: potential for disease transmission and implications for risk-based surveillance on the island of Mayotte.

Sci Rep 2018 08 1;8(1):11550. Epub 2018 Aug 1.

Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR ASTRE "Animals, Health, Territories, Risks, and Ecosystems", Montpellier, France.

The island of Mayotte is a department of France, an outermost region of the European Union located in the Indian Ocean between Madagascar and the coast of Eastern Africa. Due to its close connection to the African mainland and neighbouring islands, the island is under constant threat of introduction of infectious diseases of both human and animal origin. Here, using social network analysis and mathematical modelling, we assessed potential implications of livestock movements between communes in Mayotte for risk-based surveillance. Our analyses showed that communes in the central region of Mayotte acted as a hub in the livestock movement network. The majority of livestock movements occurred between communes in the central region and from communes in the central region to those in the outer region. Also, communes in the central region were more likely to be infected earlier than those in the outer region when the spread of an exotic infectious disease was simulated on the livestock movement network. The findings of this study, therefore, suggest that communes in the central region would play a major role in the spread of infectious diseases via livestock movements, which needs to be considered in the design of risk-based surveillance systems in Mayotte.
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http://dx.doi.org/10.1038/s41598-018-29999-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6070536PMC
August 2018

Epidemiological study of feline idiopathic cystitis in Seoul, South Korea.

J Feline Med Surg 2018 10 2;20(10):913-921. Epub 2017 Oct 2.

1 The Royal Veterinary College, Department of Pathobiology and Population Sciences, Hertfordshire, UK.

Objectives The objective of this study was to investigate potential risk factors for the diagnosis of feline idiopathic cystitis (FIC) in cats living in a primarily indoor environment. Methods A case-control study focusing on a cohort of cats attending a first-opinion veterinary practice in Seoul, South Korea, from 2012-2016, was undertaken. Data were collected from cats' owners by questionnaire and analysed using a multivariable logistic regression analysis. Results Fifty-eight cases of FIC and 281 randomly selected controls were surveyed. Over 90% of the cases and controls had no access to the outside, and 100% and 91% of the cases and controls, respectively, were neutered. The estimated prevalence of an FIC diagnosis was 1.77% (95% confidence interval [CI] 1.36-2.18). The final logistic regression model included five variables associated with an FIC diagnosis. Males had 2.34 times the odds of being diagnosed with FIC compared with females (95% CI 1.18-4.62; P = 0.015). Cats reported as not having vantage points had 4.64 times the odds of an FIC diagnosis compared with those reported as having vantage points (95% CI 2.05-10.49; P <0.001). Cats living in an apartment had 2.53 times the odds of an FIC diagnosis compared with those living in a house (95% CI 1.30-4.93; P = 0.006). Cats cohabiting with other cats were more likely to be diagnosed with FIC than those living alone (odds ratio 3.16, 95% CI 1.61-6.22; P = 0.001). Cats using non-clumping litter had 2.62 times the odds of an FIC diagnosis compared with those using clumping litter (95% CI 1.38-4.96; P = 0.003). Conclusions and relevance This study was conducted in a different epidemiological context from previous studies in that the overwhelming majority of the cats studied were housed entirely indoors. This study identified several significant associations related to a cat's indoor environment. These findings suggest that the cat's physical and social environment may play a role in the development of FIC.
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http://dx.doi.org/10.1177/1098612X17734067DOI Listing
October 2018

Neuroprotective effect by Dammishimgyu-herbal acupuncture against H(2)O(2)-induced apoptosis in human neuroblastoma, SH-SY5Y cells.

Neurol Res 2007 ;29 Suppl 1:S93-7

TKM Research Group, Kyung Hee University, Seoul 130-701, Korea.

Background: The free radical is involved in neuronal cell death in human neurodegenerative disease. Dammishimgyu (DMSG)-herbal acupuncture has been used to treat neurological disorders in Korea. The present study was aimed to investigate the neuroprotective effect of DMSG-herbal acupuncture against H(2)O(2)-induced apoptosis in human neuroblastoma cell line, SH-SY5Y.

Methods: The neuroprotective effect of DMSG-herbal acupuncture on H(2)O(2) induced apoptosis was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 4,6-diamidino-2-phenylindole (DAPI) staining, reverse transcription-polymerase chain reaction (RT-PCR), western blots and nitrite assay.

Results: In this study, 100 microM H(2)O(2)-treated cells decreased the cell viability with apoptotic features and increased the production of nitric oxide (NO). However, 0.1% DMSG treatment after exposure to 100 microM H(2)O(2) inhibited both H(2)O(2)-stimulated mRNA and protein expressions of BCL2-associated X protein (BAX) and caspase 3 apoptosis-related cysteine peptidase (CASP3). In addition, 0.1% DMSG treatment inhibited the increased NO production induced by H(2)O(2).

Conclusion: These results suggest that DMSG-herbal acupuncture shows protective effect against H(2)O(2)-induced neuronal damage.
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http://dx.doi.org/10.1179/016164107X172329DOI Listing
May 2007

Reversible pH-driven conformational switching of tethered superoxide dismutase with gold nanoparticle enhanced surface plasmon resonance spectroscopy.

J Am Chem Soc 2006 Oct;128(39):12870-8

College of Medicine and School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, San 56-1, Shillim, Kwanak, Seoul 151-742, Korea.

A new class of surface-immobilized protein nanomachines can be reversibly actuated by cycling the solution pH between 2.5 and 12.3, which induces a conformational change, thereby modulating the thickness of superoxide dismutase (SOD1) tethered to the Au thin film. By placing Au nanoparticles (AuNP) atop the immobilized SOD1 by means of a gold-thiol assembly, the nanoscale motion of SOD1 at the interface produces mechanical work to lift and then lower the AuNP from the Au substrate by a distance of ca. 3 nm and transduces this motion into an easily measurable reflectivity change in the surface plasmon resonance (SPR) spectrum. As-made supported conjugate consisting of SOD1 and AuNP is quite robust and stable, and its operation in response to pH variations, which mirrors the conformational changes of responsive SOD1 at the interface, is found to be highly reversible and reproducible. This is the first demonstration of the development of novel solid-state sensors and/or switching devices based on substrate-bound protein conformational changes and AuNP enhanced SPR spectroscopy.
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http://dx.doi.org/10.1021/ja0632198DOI Listing
October 2006
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