Effects of Omicron Infection and Changes in Serum Antibody Response to Wild-Type, Delta, and Omicron After a Booster Dose With BNT163b2 Vaccine in Korean Healthcare Workers

Background@#Although the primary vaccine coverage rate for coronavirus disease 2019 (COVID-19) in South Korea has exceeded 80%, the coronavirus continues to spread, with reports of a rapid decline in vaccine effectiveness. South Korea is administering booster shots despite concerns about the effectiveness of the existing vaccine. @*Methods@#Neutralizing antibody inhibition scores were evaluated in two cohorts after the booster dose. For the first cohort, neutralizing activity against the wild-type, delta, and omicron variants after the booster dose was evaluated. For the second cohort, we assessed the difference in neutralizing activity between the omicron infected and uninfected groups after booster vaccination. We also compared the effectiveness and adverse events (AEs) between homologous and heterologous booster doses for BNT162b2 or ChAdOx1 vaccines. @*Results@#A total of 105 healthcare workers (HCWs) that were additionally vaccinated with BNT162b2 at Soonchunhyang University Bucheon Hospital were enrolled in this study.Significantly higher surrogate virus neutralization test (sVNT) inhibition (%) was observed for the wild-type and delta variants compared to sVNT (%) for the omicron after the booster dose (97%, 98% vs. 75%; P < 0.001). No significant difference in the neutralizing antibody inhibition score was found between variants in the BNT/BNT/BNT group (n = 48) and the ChA/ChA/BNT group (n = 57). Total AEs were not significantly different between the ChA/ ChA/BNT group (85.96%) and the BNT/BNT group (95.83%; P = 0.11). In the second cohort with 58 HCWs, markedly higher sVNT inhibition to omicron was observed in the omicroninfected group (95.13%) compared to the uninfected group (mean of 48.44%; P < 0.001) after four months of the booster dose. In 41 HCWs (39.0%) infected with the omicron variant, no difference in immunogenicity, AEs, or effectiveness between homogeneous and heterogeneous boosters was observed. @*Conclusion@#Booster vaccination with BNT162b2 was significantly less effective for the neutralizing antibody responses to omicron variant compared to the wild-type or delta variant in healthy population. Humoral immunogenicity was sustained significantly high after 4 months of booster vaccine in the infected population after booster vaccination.Further studies are needed to understand the characteristics of immunogenicity in these populations.

Short-Term Effects of the Internet-Based Korea Diabetes Prevention Study: 6-Month Results of a Community-Based Randomized Controlled Trial

The aims of this study were to determine the short-term effectiveness of an internet-based lifestyle modification (LSM) program in preventing the onset of type 2 diabetes mellitus (T2DM) in prediabetes patients in community settings. A total of 415 subjects who were diagnosed with prediabetes were randomly assigned to the LSM and standard management (SM) groups. After the 6-month intervention, the LSM group had a statistically significant reduction in body weight, body mass index compared to the SM group participants. In the LSM group, blood glucose levels were significantly decreased after intervention and the clinical improvement effect was evident in the group that achieved the target weight loss of 5% or more of the initial weight for 6 months. Internet-based 6-month-intensive LSM programs conducted by public health center personnel are an effective way to provide lifestyle intervention programs and encourage maintenance of healthy behaviors in subjects with a high risk of T2DM in community settings.

Melatonin in the colon modulates intestinal microbiota in response to stress and sleep deprivation

Background/Aims@#Stress is closely related to the deterioration of digestive disease. Melatonin has potent anti-inflammatory properties. The objective of this study was to determine the effect of water stress (WS) and sleep deprivation (SD) on intestinal microbiota and roles of melatonin in stressful condition. @*Methods@#We used C57BL/6 mice and specially designed water bath for stress and SD for 10 days. We measured melatonin concentrations in serum, feces, and colon tissues by high-performance liquid chromatography. Genomic DNA was extracted from feces and amplified using primers targeting V3 to V4 regions of bacterial 16S ribosomal RNA genes. @*Results@#Compared to the control, melatonin concentration was lower in the WS and SD. Fecal concentration was 0.132 pg/mL in control, 0.062 pg/mL in WS, and 0.068 pg/mL in SD. In colon tissue, it was 0.45 pg/mL in control, 0.007 pg/mL in WS, and 0.03 pg/mL in SD. After melatonin treatment, melatonin concentrations in feces and colon tissue were recovered to the level of control. Metagenomic analysis of microbiota showed abundance in colitogenic microbiota in WS and SD. Melatonin injection attenuated this harmful effect. WS and SD showed decreased Lactobacillales and increased Erysipelotrichales and Enterobacteriales. Melatonin treatment increased Akkermansia muciniphila and Lactobacillus and decreased Bacteroides massiliensis and Erysipelotrichaceae. @*Conclusions@#This study showed that stress and SD could affect intestinal dysbiosis and increase colitogenic microbiota, which could contribute to the aggravating digestive disease. Melatonin concentrations in feces and colon tissue decreased under WS and SD. Melatonin treatment brought recovery of melatonin concentration in colon tissue and modulating dysbiosis of intestinal microbiota.

Antitumor effect of TW-37, a BH3 mimetic in human oral cancer / 한국실험동물학회지

TW-37 is a small molecule B cell lymphoma-2 (Bcl-2) homology 3 mimetic with potential anticancer activities. However, the in vivo anti-cancer effect of TW-37 in human oral cancer has not been properly studied yet. Here, we attempted to confirm antitumor activity of TW37 in human oral cancer. TW-37 significantly inhibited cell proliferation and increased the number of dead cells in MC-3 and HSC-3 human oral cancer cell lines. TW-37 enhanced apoptosis of both cell lines evidenced by annexin V/propidium iodide double staining, sub-G1 population analysis and the detection of cleaved poly (ADP-ribose) polymerase and caspase-3. In addition, TW-37 markedly downregulated the expression of Bcl-2 protein, while not affecting Bcl-xL or myeloid cell leukemia-1. In vivo, TW-37 inhibited tumor growth in a nude mice xenograft model without any significant liver and kidney toxicities. Collectively, these data reveal that TW-37 may be a promising small molecule to inhibit human oral cancer.

Investigation of bovine tuberculosis outbreaks by using a trace-back system and molecular typing in Korean Hanwoo beef cattle

Bovine tuberculosis is a chronic contagious disease responsible for major agricultural economic losses. Abattoir monitoring and trace-back systems are an appropriate method to control bovine tuberculosis, particularly in beef cattle. In the present study, a trace-back system was applied to bovine tuberculosis cases in Korean native Hanwoo beef cattle. Bovine tuberculosis was detected in three index beef cattle during abattoir monitoring in Jeonbuk Province, Korea, and the original herds were traced back from each index cow. All cattle in each original herd were subjected to tuberculin skin test. The positive rates in the tuberculin skin test were 64.6% (62 of 96), 4.8% (2 of 42), and 8.1% (3 of 37) at farms A, B, and C, respectively. On post-mortem examination of 56 tuberculin-positive cattle, 62% had granulomatous lesions, and Mycobacterium bovis was cultured from 40 (71.4%) of the cattle. Molecular typing by spoligotyping and the mycobacterial interspersed repetitive unit-variable-number tandem repeat assay revealed the genotype of the M. bovis strains from the index cattle were same as the M. bovis genotype in each original herd. The results suggest that tracing back from index cattle to the original herd is an effective method to control bovine tuberculosis in beef cattle.

Comparison of tolvaptan treatment between patients with the SIADH and congestive heart failure: a single-center experience

BACKGROUND/AIMS: Tolvaptan is a very effective treatment for hypervolemic or euvolemic hyponatremia. We compared the clinical efficacy of and response to tolvaptan in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and congestive heart failure (CHF). METHODS: We retrospectively reviewed the medical records of 50 patients (SIADH, n = 30; CHF, n = 20) who were prescribed tolvaptan between July 2013 and October 2015. Tolvaptan was prescribed when the serum sodium level was 135 mmol/L. RESULTS: After the initiation of tolvaptan therapy, there was an immediate response in the urine volume and serum sodium level in all patients. The improvements in the urine volume and serum sodium concentration were highest within the first 24 hours of treatment. In addition, the mean change in the serum sodium level during the first 24 hours was significantly higher in patients with SIADH than in those with CHF (∆Na, 9.9 ± 4.5 mmol/L vs. 6.9 ± 4.4 mmol/L, respectively; p = 0.025). Also, the mean maintenance dose was lower, and the total duration of tolvaptan use was slightly shorter in the SIADH group than CHF group (21.5 ± 14.9 days vs. 28.0 ± 20.1 days, p = 0.070). CONCLUSIONS: The early response to tolvaptan treatment was better in patients with SIADH than in those with CHF. Thus, the tolvaptan treatment strategy should be differed between patients with SIADH and those with CHF.

Needs for Development of IT-based Nutritional Management Program for Women with Gestational Diabetes Mellitus / 대한지역사회영양학회지

OBJECTIVES: The aim of this study was to examine self-management status, nutritional knowledge, barrier factors in dietary management and needs of nutritional management program for women with Gestational Diabetes Mellitus (GDM). METHODS: A total of 100 women with GDM were recruited from secondary and tertiary hospitals in Seoul. The questionnaire composed of general characteristics, status of self-management, dietary habits, nutrition knowledge, barrier factors in dietary management, needs for nutrition information contents and nutritional management programs. Data were collected by a self-administered questionnaire. All data were statistically analyzed using student's t-test and chi-square test using SAS 9.3. RESULTS: About 35% of the subjects reported that they practiced medical nutrition and exercise therapy for GDM control. The main sources of nutrition information were ‘internet (50.0%)’ and ‘expert advice (45.0%)’. More than 70% of the subjects experienced nutrition education. The mean score of nutrition knowledge was 7.5 point out of 10, and only about half of the subjects were reported to be correctly aware of some questions such as ‘the cause of ketosis’, ‘the goal of nutrition management for GDM’, ‘the importance of sugar restriction on breakfast’. The major obstructive factors in dietary management were ‘eating more than planned when dining out’, ‘finding the appropriate menu when dining out’. The preferred nutrition information contents in developing management program were ‘nutritional information of food’, ‘recommended food by major nutrients’, ‘the relationship between blood glucose and food’, ‘tips on menu selection at eating out’. The subjects reported that they need management program such as ‘example of menu by calorie prescription’, ‘recommended weight gain guide’, ‘meal recording and dietary assessment’, ‘expert recommendation’, ‘sharing know-how’. CONCLUSIONS: Based on the results of this study, it is necessary to develop a program that provide personalized information by identifying the individual characteristics of the subjects and expert feedback function through various information and nutrition information contents that can be used in real life.

Gene Regulatory Network Analysis for Triple-Negative Breast Neoplasms by Using Gene Expression Data / 한국유방암학회지

PURPOSE: To better identify the physiology of triple-negative breast neoplasm (TNBN), we analyzed the TNBN gene regulatory network using gene expression data. METHODS: We collected TNBN gene expression data from The Cancer Genome Atlas to construct a TNBN gene regulatory network using least absolute shrinkage and selection operator regression. In addition, we constructed a triple-positive breast neoplasm (TPBN) network for comparison. Furthermore, survival analysis based on gene expression levels and differentially expressed gene (DEG) analysis were carried out to support and compare the network analysis results, respectively. RESULTS: The TNBN gene regulatory network, which followed a power-law distribution, had 10,237 vertices and 17,773 edges, with an average vertex-to-vertex distance of 8.6. The genes ZDHHC20 and RAPGEF6 were identified by centrality analysis to be important vertices. However, in the DEG analysis, we could not find meaningful fold changes in ZDHHC20 and RAPGEF6 between the TPBN and TNBN gene expression data. In the multivariate survival analysis, the hazard ratio for ZDHHC20 and RAPGEF6 was 1.677 (1.192–2.357) and 1.676 (1.222–2.299), respectively. CONCLUSION: Our TNBN gene regulatory network was a scale-free one, which means that the network would be easily destroyed if the hub vertices were attacked. Thus, it is important to identify the hub vertices in the network analysis. In the TNBN gene regulatory network, ZDHHC20 and RAPGEF6 were found to be oncogenes. Further study of these genes could help to reveal a novel method for treating TNBN in the future.

Levodropropizine-Induced Anaphylaxis: Case Series and Literature Review

Levodropropizine is commonly used as an antitussive drug for acute and chronic cough. It is a non-opioid agent with peripheral antitussive action via the modulation of sensory neuropeptide levels in the airways. Thus, levodropropizine has a more tolerable profile than opioid antitussives. However, we experienced 3 cases of levodropropizine-induced anaphylaxis. Three patients commonly presented with generalized urticaria, dyspnea, and collapse after taking cold medication including levodropropizine. To find out the culprit drug, we performed skin tests, oral provocation tests (OPTs), and basophil activation tests (BATs). Two patients were confirmed as having levodropropizine-induced anaphylaxis by OPTs, and one of them showed positive to skin prick tests (SPTs). The other patient was confirmed by skin tests and BATs. When we analyzed pharmacovigilance data related to levodropropizine collected for 5 years, most cases (78.9%) had allergic reactions, such as rash, urticaria, angioedema, and anaphylaxis. Therefore, physicians should consider that levodropropizine can be a culprit drug, when anaphylaxis occurs after taking anti-cough or common cold medication.

The Utility of Measuring the Difference between the Two Optic Nerve Sheath Diameters Using Ultrasonography in Predicting Operation Indication in Patients with Traumatic Brain Hemorrhage

PURPOSE: An increase in optic nerve sheath diameter (ONSD) has been associated with elevated intracranial pressure due to brain lesions, such as hemorrhage, infarction, and tumor. The aim of this study was to evaluate whether the difference of both ONSDs can predict surgical treatment in patients with traumatic brain hemorrhage. METHODS: A prospective analysis of the data acquired between September 2016 and November 2016 was performed. We included 155 patients with traumatic brain hemorrhage undergoing computed tomography in the emergency room. We performed an ultrasonography to measure ONSDs for all included patients. The primary outcome of this study was operation indication in patients with traumatic brain hemorrhage. RESULTS: The average age was 63.4±17.0 years (male 60.3±17.3, female 69.8±14.4). There were 61 (39.35%) patients with an indication for operation and 94 (60.65%) patients with an indication for no operation. Indications for operation showed a strong association with the difference of both ONSDs in patients with subdural hemorrhage (p<0.001), no association between them in patients with epidural and intracerebral hemorrhage. In patients with subdural hemorrhage, the area under the curve was 0.988 (0.653-0.998), and the cut-off value for the difference of ONSDs with respect to determining the indications for operation was 0.295 mm f maximizing the sum of the sensitivity (96.9%) and specificity (90.7%) using the receiver operating curve. CONCLUSION: A difference of both ONSDs above 0.295 mm was useful in predicting the indications for operation in patients with traumatic subdural hemorrhage, but not in patients with epidural and intracerebral hemorrhage.

Isolation and characterization of Brucella abortus isolates from wildlife species in South Korea

A total of 782 blood and 465 tissue samples from 1,039 wild animals and 127 dairy goats were collected from January 2011 to December 2013 in 10 provinces of South Korea and tested for the presence of brucellosis. The Rose Bengal test revealed that 8.0% (52/650) of the serum samples were seropositive, while 4.2% (33/782) of the serum samples were positive for Brucella antibodies by competitive enzyme-linked immunosorbent assay. Of the 650 sera examined, only 16 (2.5%) were positive by both serological tests. Direct polymerase chain reaction (PCR) assay using B4/B5 primers for Brucella abortus (BCSP31) revealed the prevalence of Brucella to be 26.5% (129/487) in blood samples and 21% (98/465) in tissue samples while, 16S rRNA PCR detected Brucella DNA in 6.8% (33/487) and 2.6% (12/465) in blood and tissue samples, respectively. Of PCR-positive samples, only 6.2% (30/487) of blood samples and 2.4% (11/465) of tissue samples were found to be positive by both BCSP31 and 16S rRNA PCRs. However, Brucella strains were isolated by blood culture from only two out of 487 blood samples (0.4%). This characterization and identification of pathogenic Brucella isolates is the first to clearly indicate that the organisms were Brucella abortus biovar 1.

A case of levocetirizine-induced liver injury

Levocetirizine is a second-generation nonsedative antihistaminic agent that has been demonstrated to be safe and effective for treating allergic disease. There was only one case report of levocetirizine-induced liver toxicity, but a liver biopsy was not performed. In this article, we present the first case of levocetirizine-induced liver injury with histologic findings. A 48-year-old man was hospitalized with jaundice and generalized pruritus that had developed after 2 months of therapy with levocetirizine for prurigo nodularis. Laboratory findings revealed acute hepatitis with cholestasis. A liver biopsy demonstrated portal inflammation and hepatitis with apoptotic hepatocytes. The patient fully recovered 3 weeks after withdrawing levocetirizine. Although levocetirizine is safe and effective, physicians should be aware of its potential hepatotoxicity.

Mycobacterium bovis infection in a wild sow (Sus scrofa): the first case in Korea

Mycobacterium (M.) bovis causes tuberculosis and has a broad host range, including humans, livestock, and wild animals. M. bovis infection of wild boar has been reported in several European countries. We report here the first case of M. bovis infection in a domesticated wild sow in Korea. Granulomatous and necrotizing lesions with small numbers of acid-fast bacilli were observed in nodules of the lung of wild sow. Furthermore, the M. bovis isolate from the wild sow had spoligotype SB0140 and a novel MIRU-VNTR allelic profile, which is not found in cattle and deer in Korea.

Near-Road Exposure and Impact of Air Pollution on Allergic Diseases in Elementary School Children: A Cross-Sectional Study

PURPOSE: The study aims to classify schools based on traffic pollutants and their complex sources, to assess the environment, to determine the state of allergic diseases among students using the International Study of Asthma and Allergies in children (ISAAC) questionnaire, and to assess their connection to air pollutants. MATERIALS AND METHODS: A total of seven schools were divided into three categories according to the characteristics of their surrounding environments: three schools in traffic-related zones, two schools in complex source zones I (urban), and two schools in complex source zones II (industrial complex). ISAAC questionnaires were administered and the 4404 completed questionnaires were analyzed. RESULTS: The frequency of asthma treatment during the past 12 months showed a significant increase (p<0.05) with exposure to NO2 [1.67, 95% confidence intervals (CIs) 1.03-2.71] in the complex source zones. The frequency of allergic rhinitis treatment during the past 12 months increased significantly with exposure to Black Carbon (1.60, 95% CIs 1.36-1.90) (p<0.001), SO2 (1.09, 95% CIs 1.01-1.17) (p<0.05), NO2 (1.18, 95% CIs 1.07-1.30) (p<0.01) for all subjects. CONCLUSION: In terms of supporting children's health, care, and prevention related to major spaces for children, such as school zones, spaces used in coming to and leaving school, playgrounds, and classrooms are essential to ensuring not only the safety of children from traffic accidents but also their protection from local traffic pollutants and various hazardous environmental factors.

Identification of Brucella melitensis isolates originating from Mongolia and diagnostic real-time PCR evaluation using a specific SNP / 대한수의학회지

A real-time PCR assay using hybridization probe (HybProbe) has been developed to detect Brucella (B.) melitensis strains. The primer and HybProbe sets were designed based on the gap gene of chromosome I with a specific single nucleotide polymorphism of B. melitensis. Specificity of the assay was confirmed by comparison to reference Brucella species and other related strains. In the melting curve analysis, B. melitensis generated a peak at 67degrees C unlike those for other Brucella species observed at 61degrees C. Sensitivity of the assay for B. melitensis ranged from 20 ng to 200 fg of genomic DNA. The ability to identify 94 Mongolian B. melitensis isolates using the real-time PCR assay was identical to that of classical biotyping methods and differential multiplex PCR. These data showed that this new molecular technique is a simple and quick method for detecting B. melitensis, which will be important for the control and prevention of brucellosis.

Biological Property of Recombinant Hemagglutinin-Neuraminidase Protein of Avian Paramyxovirus Type 6 Expressed by Recombinant Baculovirus

Hemagglutination inhibition (HI) test employing whole virus antigen is a prescribed serological test for serotyping, diagnosis and surveillance for avian paramyxoviruses (APMVs). For use as alternative to the virus antigen, hemagglutinin-neuraminidase (HN) protein gene of the wild duck isolate APMV-6/WB12-163FS of APMV serotype 6 (APMV-6) was amplified, cloned and expressed in Spodoptera frugiperda insect cells. The HN gene of 1,842 bps in length showed nucleotide and amino acid homology of 93.4% and 97.1%, respectively with that of APMV-6 prototype strain. Putative sialic acid binding motif and potential N-linked glycosylation sites were conserved. In Western blot analysis, the expressed protein had a molecular mass of 66 kDa and reacted specifically with antiserum to APMV-6. In addition, the recombinant HN protein showed biological properties such as hemagglutination (HA) and elution. The recombinant HN protein produced from infected cells showed high HA titers (approximately 2(13) HA unit/ml). The HA activity of the recombinant HN protein was inhibited by antisera to APMV-6. In cross HA inhibition test, the recombinant HN protein had the highest titers with antisera to homologous APMV serotype, although there was weak cross reaction with some of antisera to other APMV serotypes. Our results indicated that recombinant APMV-6 HN protein would have the potential as alternative to the APMV-6 antigen in HI assays.

Seroprevalence of Q-fever in Korean native cattle / 대한수의학회지

Q-fever is a vector-borne (Coxiella [C.] burnetii) zoonotic disease that is an increasing public health concern. To date, some research about Q-fever prevalence in dairy herds and human patients has been reported in Korea, but information about Korean native cattle is scarce. To measure the prevalence rates of C. burnetii in Korean native cattle, a total of 1,095 bovine serum samples collected during 2010~2013 were analyzed with an enzyme-linked immunosorbent assay. Sixty-eight heads of cattle were diagnosed as positive and while 19 heads were suspected (positive rate = 6.2%). Interestingly, Jeju province had a seropositivity rate six times greater than that of other provinces (18.9% vs. 3.2%). High seroprevalence might be caused by wide distribution of ticks in Jeju province compared to other regions. Based on these data, extensive monitoring of C. burnetii infection in cattle, tick distribution, and climate changes is required.

Seroprevalence of Q-fever in Korean native cattle / 대한수의학회지

Q-fever is a vector-borne (Coxiella [C.] burnetii) zoonotic disease that is an increasing public health concern. To date, some research about Q-fever prevalence in dairy herds and human patients has been reported in Korea, but information about Korean native cattle is scarce. To measure the prevalence rates of C. burnetii in Korean native cattle, a total of 1,095 bovine serum samples collected during 2010~2013 were analyzed with an enzyme-linked immunosorbent assay. Sixty-eight heads of cattle were diagnosed as positive and while 19 heads were suspected (positive rate = 6.2%). Interestingly, Jeju province had a seropositivity rate six times greater than that of other provinces (18.9% vs. 3.2%). High seroprevalence might be caused by wide distribution of ticks in Jeju province compared to other regions. Based on these data, extensive monitoring of C. burnetii infection in cattle, tick distribution, and climate changes is required.

Epidemiology of brucellosis among cattle in Korea from 2001 to 2011

In the present study, the outbreak patterns of bovine brucellosis in Korea from 2000 to 2011 were analyzed to understand the epidemiological evolution of this disease in the country. A total of 85,521 brucella reactor animals were identified during 14,215 outbreaks over the 12-year study period. The number of bovine brucellosis cases increased after 2003 and peaked in 2006 before decreasing thereafter. The majority of the bovine brucellosis cases were Korean native cattle, Han Woo. The numbers of human brucellosis cases and cattle outbreaks increased and decreased in the same pattern. The correlation coefficient for human and bovine cases per year was 0.96 (95% confidence interval = 0.86~0.99; p < 10(-3)). The epidemiological characteristics of bovine brucellosis appeared to be affected by the intensity of eradication programs that mainly involved a test-and-slaughter policy. Findings from the present study were based on freely available statistics from web pages maintained by government agencies. This unlimited access to information demonstrates the usefulness of government statistics for continually monitoring the health of animal populations.

Antimicrobial resistance of Escherichia coli isolated from healthy animals during 2010-2012 / 대한수의학회지

The purpose of present study was to investigate the antimicrobial resistance in Escherichia coli isolated from healthy animals in all provinces of the Republic of Korea. A total of 2,085 E. coli strains isolated from 11,336 fecal samples of healthy animals during 2010-2012 were examined for antimicrobial resistance. Comparison of average resistance rate through the years revealed that tetracycline (47.0% and 76.1%) and streptomycin resistance (42.6% and 64.6%) was most frequently observed in cattle and pigs, respectively. Whereas, in chicken isolates, resistance against nalidixic acid (90.9%) was highest among the antimicrobials tested. Percentage of E. coli that showed multidrug resistance (resistance against > or = three subclasses of antimicrobial agents) was 17.6% (151/860) in cattle, 69.4% (506/729) in pigs, and 86.1% (427/496) in chickens. Overall, the rates of resistance are apparently different between animal species and, in particular, resistance was less prevalent in cattle than in pigs and chickens. In conclusion, this study showed higher prevalence of resistance in commensal E. coli strains to antimicrobial agents in Korean livestock and highlighted the urgent need for measures to regulate the abuse of antimicrobial agents.