Classification of gait variation under mental workload in big five personalities.

BACKGROUND: Human behavior patterns involve mutual interactions among psychology, physiology, and stress, which are all associated with gait at different grades. RESEARCH QUESTIONS: The study aims to reveal the interrelationship among personality, mental workload, and gait patterns by capturing gait variations using inertial sensors. It also assesses individual personality traits and simulates stress to construct a gait classification model. METHODS: Sixty participants were instructed to perform regular, low, and high mental workload walking on the corridor to simulate a natural setting walking. Meanwhile inertial measurement units (IMUs) were placed on eight body parts. Mental workload was induced using the auditory n-back task, and their Big Five personality traits were evaluated. Gait data from IMUs were categorized into nine classifications of average, low, and high Big Five Inventory scores with three levels of mental workload walking. Subsequently, the segmentation gait data were used as input features for classifications in deep learning models, employing a sliding window long short-term memory network for nine classifications for different personality dimensions. RESULTS: The results indicated average accuracies of nine classifications were 83.6 % for Openness, 84.4 % for Conscientiousness, 82.0 % for Extraversion, 85.2 % for Agreeableness, and 84.5 % for Neuroticism across all IMU placements. Remarkably, gait data from the lower back IMU achieved the highest model performance, with an average accuracy of 92.7 %, in classifying the different levels of personality and mental workload walking. In contrast, the left wrist and chest showed several misclassifications among regular, low, and high mental workload walking across personality traits. SIGNIFICANCE: Successful classification can help monitor an individual's mental state in real time and analyze personality dimensions, providing feedback and suggestions. The present study demonstrated that gait characteristics can contribute to more profound and personalized health information.

Exploring the Regulatory Landscape of Dementia: Insights from Non-Coding RNAs.

Dementia, a multifaceted neurological syndrome characterized by cognitive decline, poses significant challenges to daily functioning. The main causes of dementia, including Alzheimer's disease (AD), frontotemporal dementia (FTD), Lewy body dementia (LBD), and vascular dementia (VD), have different symptoms and etiologies. Genetic regulators, specifically non-coding RNAs (ncRNAs) such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are known to play important roles in dementia pathogenesis. MiRNAs, small non-coding RNAs, regulate gene expression by binding to the 3' untranslated regions of target messenger RNAs (mRNAs), while lncRNAs and circRNAs act as molecular sponges for miRNAs, thereby regulating gene expression. The emerging concept of competing endogenous RNA (ceRNA) interactions, involving lncRNAs and circRNAs as competitors for miRNA binding, has gained attention as potential biomarkers and therapeutic targets in dementia-related disorders. This review explores the regulatory roles of ncRNAs, particularly miRNAs, and the intricate dynamics of ceRNA interactions, providing insights into dementia pathogenesis and potential therapeutic avenues.

Exploring the Key Signaling Pathways and ncRNAs in Colorectal Cancer.

Colorectal cancer (CRC) is the third most prevalent cancer to be diagnosed, and it has a substantial mortality rate. Despite numerous studies being conducted on CRC, it remains a significant health concern. The disease-free survival rates notably decrease as CRC progresses, emphasizing the urgency for effective diagnostic and therapeutic approaches. CRC development is caused by environmental factors, which mostly lead to the disruption of signaling pathways. Among these pathways, the Wingless/Integrated (Wnt) signaling pathway, Phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway, Mitogen-Activated Protein Kinase (MAPK) signaling pathway, Transforming Growth Factor-ß (TGF-ß) signaling pathway, and p53 signaling pathway are considered to be important. These signaling pathways are also regulated by non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). They have emerged as crucial regulators of gene expression in CRC by changing their expression levels. The altered expression patterns of these ncRNAs have been implicated in CRC progression and development, suggesting their potential as diagnostic and therapeutic targets. This review provides an overview of the five key signaling pathways and regulation of ncRNAs involved in CRC pathogenesis that are studied to identify promising avenues for diagnosis and treatment strategies.

The human PTGR1 gene expression is controlled by TE-derived Z-DNA forming sequence cooperating with miR-6867-5p.

Z-DNA, a well-known non-canonical form of DNA involved in gene regulation, is often found in gene promoters. Transposable elements (TEs), which make up 45% of the human genome, can move from one location to another within the genome. TEs play various biological roles in host organisms, and like Z-DNA, can influence transcriptional regulation near promoter regions. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that play a critical role in the regulation of gene expression. Although TEs can generate Z-DNA and miRNAs can bind to Z-DNA, how these factors affect gene transcription has yet to be elucidated. Here, we identified potential Z-DNA forming sequence (ZFS), including TE-derived ZFS, in the promoter of prostaglandin reductase 1 (PTGR1) by data analysis. The transcriptional activity of these ZFS in PTGR1 was confirmed using dual-luciferase reporter assays. In addition, we discovered a novel ZFS-binding miRNA (miR-6867-5p) that suppressed PTGR1 expression by targeting to ZFS. In conclusion, these findings suggest that ZFS, including TE-derived ZFS, can regulate PTGR1 gene expression and that miR-6867-5p can suppress PTGR1 by interacting with ZFS.

Factors Related to Suicidal Ideation in Adolescents According to Types of Stress.

Background: We aimed to identify the factors associated with suicidal ideation by classifying adolescents into three groups: no stress, interpersonal stress, as well as academic and career stress. Method: Using the data from the 16th Korea Youth Risk Behavior Web-Based Survey (2020), 15,343 adolescents were included in the study, and their socio-demographic characteristics as well as physical and psychological factors were assessed. A complex sample logistic regression was performed to identify factors associated with suicide. Results: The following factors were significantly associated with suicide: fatigue recovery by sleep, body mass index, physical activity, and depression in the no stress group; current school, academic grade, drinking, depression, loneliness, and anxiety in the interpersonal stress group; and gender, current school, academic grade, father's educational level, drinking, fatigue recovery by sleep, depression, loneliness, subjective health, smartphone overdependence, as well as anxiety in the academic and career stress group (P < 0.05). Conclusion: To prevent suicide among adolescents, it is necessary to consider these factors when developing educational policies.

Identification of microRNAs Derived from Transposable Elements in the Macaca mulatta (Rhesus Monkey) Genome.

Transposable elements (TEs) are mobile DNA entities that can move within the host genome. Over long periods of evolutionary time, TEs are typically silenced via the accumulation of mutations in the genome, ultimately resulting in their immobilization. However, they still play an important role in the host genome by acting as regulatory elements. They influence host transcription in various ways, one of which as the origin of the generation of microRNAs (miRNAs), which are so-called miRNAs derived from TEs (MDTEs). miRNAs are small non-coding RNAs that are involved in many biological processes by regulating gene expression at the post-transcriptional level. Here, we identified MDTEs in the Macaca mulatta (rhesus monkey) genome, which is phylogenetically close species to humans, based on the genome coordinates of miRNAs and TEs. The expression of 5 out of 17 MDTEs that were exclusively registered in M. mulatta from the miRBase database (v22) was examined via quantitative polymerase chain reaction (qPCR). Moreover, Gene Ontology analysis was performed to examine the functional implications of the putative target genes of the five MDTEs.

Recognition of walking directional intention employed ground reaction forces and center of pressure during gait initiation.

BACKGROUND: Movement intentions are generally classified by Electroencephalogram (EEG) and have been used in gait initiation prediction. However, it is not easy to collect EEG data and practical in reality. Alternatively, ground reaction force (GRF) and the center of pressure (COP) is produced by the contact between the foot and the ground during a specific period of walking, which are the characteristics of evaluating gait performance RESEARCH QUESTION: The study aims to use a deep learning technique to recognize the data of the COP and GRF to classify straight walking and right turn. Second, the study aims to reveal gait characteristics that could replace EEG to predict walking directional intentions METHODS: Ten healthy male adults were instructed to stand on the force platform and self-selected to perform three conditions: standstill, straight walking, and right turn. The onset of gait initiation was evaluated by muscle activation of the right tibialis anterior, and EEG and the COP displacement evaluated the onset of gait intention. Subsequently, GRF and COP would be treated as features to classify the gait intention in the Long Short-Term Memory (LSTM) model. RESULTS: The results revealed that the onset of EEG and the COP displacement initiation were statistically significant differences between straight walking and right turn. For the classification, the average accuracy of the LSTM model with GRF and COP as features reached the highest one, 94.79 %, depending on the heel- or toe-off of the swing leg. The results indicated that gait intentions could be classified based on the GRF and COP. SIGNIFICANCE: The machine learning technique of LSTM with gait parameters can recognize the gait intention of changing walking orientation. Our model and approach would be expected to provide advanced predictions, such as exoskeleton control or pedestrian traffic flow.

Human Endogenous Retrovirus-H-Derived miR-4454 Inhibits the Expression of DNAJB4 and SASH1 in Non-Muscle-Invasive Bladder Cancer.

Although most human endogenous retroviruses (HERVs) have been silenced and lost their ability to translocate because of accumulated mutations during evolution, they still play important roles in human biology. Several studies have demonstrated that HERVs play pathological roles in numerous human diseases, especially cancer. A few studies have revealed that long non-coding RNAs that are transcribed from HERV sequences affect cancer progression. However, there is no study on microRNAs derived from HERVs related to cancer. In this study, we identified 29 microRNAs (miRNAs) derived from HERV sequences in the human genome. In particular, we discovered that miR-4454, which is HERV-H-derived miRNA, was upregulated in non-muscle-invasive bladder cancer (NMIBC) cells. To figure out the effects of upregulated miR-4454 in NMIBC, genes whose expression was downregulated in NMIBC, as well as tumor suppressor genes, were selected as putative target genes of miR-4454. The dual-luciferase assay was used to determine the negative relationship between miR-4454 and its target genes, DNAJB4 and SASH1, and they were confirmed to be promising target genes of miR-4454. Taken together, this study suggests that the upregulation of miR-4454 derived from HERV-H in NMIBC reduces the expression of the tumor suppressor genes, DNAJB4 and SASH1, to promote NMIBC progression.

The Tumorigenic Role of Circular RNA-MicroRNA Axis in Cancer.

Circular RNAs (circRNAs) are a class of endogenous RNAs that control gene expression at the transcriptional and post-transcriptional levels. Recent studies have increasingly demonstrated that circRNAs act as novel diagnostic biomarkers and promising therapeutic targets for numerous cancer types by interacting with other non-coding RNAs such as microRNAs (miRNAs). The miRNAs are presented as crucial risk factors and regulatory elements in cancer by regulating the expression of their target genes. Some miRNAs are derived from transposable elements (MDTEs) that can transfer their location to another region of the genome. Genetic interactions between miRNAs and circular RNAs can form complex regulatory networks with various carcinogenic processes that play critical roles in tumorigenesis and cancer progression. This review focuses on the biological regulation of the correlative axis among circular RNAs, miRNAs, and their target genes in various cancer types and suggests the biological importance of MDTEs interacting with oncogenic or tumor-suppressive circRNAs in tumor progression.

E3 ligase adaptor FBXO7 contributes to ubiquitination and proteasomal degradation of SIRT7 and promotes cell death in response to hydrogen peroxide.

Parkinson's disease (PD) is a degenerative disorder of the central nervous system that affects 1% of the population over the age of 60. Although aging is one of the main risk factors for PD, the pathogenic mechanism of this disease remains unclear. Mutations in the F-box-only protein 7 (FBXO7) gene have been previously found to cause early onset autosomal recessive familial PD. FBXO7 is an adaptor protein in the SKP1-Cullin-1-F-box (SCF) E3 ligase complex that facilitates the ubiquitination of substrates. Sirtuin 7 (SIRT7) is an NAD+-dependent histone deacetylase that regulates aging and stress responses. In this study, we identified FBXO7 as a novel E3 ligase for SIRT7 that negatively regulates intracellular SIRT7 levels through SCF-dependent Lys-48-linked polyubiquitination and proteasomal degradation. Consequently, we show that FBXO7 promoted the blockade of SIRT7 deacetylase activity, causing an increase in acetylated histone 3 levels at the Lys-18 and Lys-36 residues and the repression of downstream RPS20 gene transcription. Moreover, we demonstrate that treatment with hydrogen peroxide triggered the FBXO7-mediated degradation of SIRT7, leading to mammalian cell death. In particular, the PD-linked FBXO7-R498X mutant, which reduced SCF-dependent E3 ligase activity, did not affect the stability of SIRT7. Collectively, these findings suggest that FBXO7 negatively regulates SIRT7 stability and may suppress the cytoprotective effects of SIRT7 during hydrogen peroxide-induced mammalian cell death.

Integration of TE Induces Cancer Specific Alternative Splicing Events.

Alternative splicing of messenger RNA (mRNA) precursors contributes to genetic diversity by generating structurally and functionally distinct transcripts. In a disease state, alternative splicing promotes incidence and development of several cancer types through regulation of cancer-related biological processes. Transposable elements (TEs), having the genetic ability to jump to other regions of the genome, can bring about alternative splicing events in cancer. TEs can integrate into the genome, mostly in the intronic regions, and induce cancer-specific alternative splicing by adjusting various mechanisms, such as exonization, providing splicing donor/acceptor sites, alternative regulatory sequences or stop codons, and driving exon disruption or epigenetic regulation. Moreover, TEs can produce microRNAs (miRNAs) that control the proportion of transcripts by repressing translation or stimulating the degradation of transcripts at the post-transcriptional level. Notably, TE insertion creates a cancer-friendly environment by controlling the overall process of gene expression before and after transcription in cancer cells. This review emphasizes the correlative interaction between alternative splicing by TE integration and cancer-associated biological processes, suggesting a macroscopic mechanism controlling alternative splicing by TE insertion in cancer.

Targeted next-generation sequencing for comprehensive genetic analysis of external apical root resorption during orthodontic treatment with premolar extraction in the Korean population.

INTRODUCTION: External apical root resorption (EARR) is one of the most common unfavorable consequences of orthodontic treatment and causes loss of tooth structure. The present study aimed to investigate the genetics of EARR using next-generation sequencing comprehensively. METHODS: Targeted next-generation sequencing was performed for comprehensive genetic analysis of 118 Korean orthodontic patients. The patients were divided into 2 groups on the basis of their EARR value. The association of clinical and genetic parameters with EARR was assessed using the χ2 test or t test for matched pairs, followed by Bonferroni correction and linear regression analysis. In addition, haplotype analysis and in silico prediction were conducted to evaluate functional effects. RESULTS: No statistically significant difference was observed between clinical and treatment-related parameters and EARR. The single nucleotide polymorphisms SPP1 rs9138 (P = 0.001) and SFRP2 rs3810765 (P = 0.04) showed only nominal significance between EARR groups. However, these 2 SNPs were not significant after Bonferroni correction for multiple testing (cutoff P = 0.05/142 = 3.52 × 10-4). Variations in SPP1 rs9138 and SFRP2 rs3810765 may be related to EARR during orthodontic treatment. In summary, not only genes related to inflammatory reactions but also those related to Wnt signaling to affect the degree of EARR during orthodontic teeth movement.

Genomic Analyses of Non-Coding RNAs Overlapping Transposable Elements and Its Implication to Human Diseases.

It is estimated that up to 80% of the human genome is transcribed into RNA molecules but less than 2% of the genome encodes the proteins, and the rest of the RNA transcripts that are not translated into protein are called non-coding RNAs (ncRNAs). Many studies have revealed that ncRNAs have biochemical activities as epigenetic regulators at the post-transcriptional level. Growing evidence has demonstrated that transposable elements (TEs) contribute to a large percentage of ncRNAs' transcription. The TEs inserted into certain parts of the genome can act as alternative promoters, enhancers, and insulators, and the accumulation of TEs increases genetic diversity in the human genome. The TEs can also generate microRNAs, so-called miRNA-derived from transposable elements (MDTEs), and are also implicated in disease progression, such as infectious diseases and cancer. Here, we analyzed the origin of ncRNAs and reviewed the published literature on MDTEs related to disease progression.

Z-DNA-Containing Long Terminal Repeats of Human Endogenous Retrovirus Families Provide Alternative Promoters for Human Functional Genes.

Transposable elements (TEs) account for approximately 45% of the human genome. TEs have proliferated randomly and integrated into functional genes during hominoid radiation. They appear as right-handed B-DNA double helices and slightly elongated left-handed Z-DNAs. Human endogenous retrovirus (HERV) families are widely distributed in human chromosomes at a ratio of 8%. They contain a 5'-long terminal repeat (LTR)-gag-pol-env-3'-LTR structure. LTRs contain the U3 enhancer and promoter region, transcribed R region, and U5 region. LTRs can influence host gene expression by acting as regulatory elements. In this review, we describe the alternative promoters derived from LTR elements that overlap Z-DNA by comparing Z-hunt and DeepZ data for human functional genes. We also present evidence showing the regulatory activity of LTR elements containing Z-DNA in GSDML. Taken together, the regulatory activity of LTR elements with Z-DNA allows us to understand gene function in relation to various human diseases.

Multiple inertial measurement unit combination and location for recognizing general, fatigue, and simulated-fatigue gait.

BACKGROUND: Muscle fatigue of the lower limbs results in dynamic imbalance and gait instability, increasing the risk of falling. However, people might slow walk without physical muscle fatigue due to mental fatigue. Wearable inertial measurement units (IMU) and machine learning approaches have been well employed for recognizing human activities. RESEARCH QUESTION: The study aims to use a machine learning technique to recognize the data collected from IMUs for physically fatigued or slow-walking gaits. Second, the study aims to reveal the location or the number of IMUs can have the best performance. METHODS: Sixteen healthy adults with six IMUs attached to their heels, toes, sacrum, and head participated in the experiment. On the first day, the participants were instructed to walk along a hallway before and after the fatigue protocol as the Pre- and Post-fatigue gait. On the second day, the participants were instructed to walk along a hallway following the beat of their fatigue gait cadence measured on the first day as the simulated cadence (SC) gait. Gait cycles of each condition were segmented as the inputs of the Long Short-Term Memory (LSTM) model for recognization. RESULTS: The result revealed that the LSTM model could recognize the gait of simulated cadence with the highest accuracy among these three gaits. For the signal body part, the highest accuracy was 93.20 % observed at the IMUs of toes. For the best combination, the IMUs of toes and sacrum achieved the highest accuracy of 95.71 %. SIGNIFICANCE: The machine learning technique of LSTM with one or more IMUs can recognize the gait under normal, physical fatigue, or simulated cadence without muscle fatigue. Our model and approach would be expected to provide conditional warning in multiple fields, such as industrial safety for potential applications.

Downregulated pol-miR-140-3p induces the expression of the kinesin family member 5A against Streptococcus parauberis infection in olive flounder.

MicroRNAs (miRNAs) are small non-coding RNAs that participate in various biological and cellular processes by regulating target gene expression. miRNAs are also known to play vital roles in the pathogenesis of various diseases, including infections, as well as the disease progression and defense responses. In this study, we examined the expression levels of pol-miR-140-3p and its target gene, kinesin family member 5A (KIF5A), in association with the Streptococcus parauberis (S. parauberis) infection, a major bacterial pathogen that causes streptococcosis in olive flounder (Paralichthys olivaceus). KIF5A is a heavy chain isoform of kinesin-1, which is known to be brain-specific, and this study is the first examination of KIF5A expression related to the regulation of miRNA in olive flounder (named PoKIF5A). There were significant differences in expression levels between infected and healthy olive flounder as the expression of pol-miR-140-3p in the infected fish was lower than that in the control, while the expression of PoKIF5A was higher in the infected fish than in the healthy controls. These contradictory results suggest that downregulated pol-miR-140-3p induces the expression of PoKIF5A against S. parauberis infection in olive flounder.

Automatic real-time occupational posture evaluation and select corresponding ergonomic assessments.

The objective is to develop a system to automatically select the corresponding assessment scales and calculate the score of the risk based on the joint angle information obtained from the imaged process (OpenPose) via image-based motion capture technology. Current occupational assessments, for example, REBA, RULA, and OWAS were used to evaluate the risk of musculoskeletal disorders. However, the assessment result would not be reported immediately. Introducing real-time occupational assessments in different working environments will be helpful for occupational injury prevention. In this study, the decision tree was developed to select the most appropriate assessment method according to the joint angles derived by OpenPose image process. Fifteen operation videos were tested and these videos can be classified into six types including maintenance, handling, assembly, cleaning, office work, and driving. The selected ergonomic assessment method by our developed decision tree in each condition are consistent with the recommendation of the Labour Research Institute. Moreover, the high-risk posture could be identified immediately and provide to the inspector for further evaluation on this posture rather than the whole operation period. This approach provides a quick inspection of the operation movements to prevent musculoskeletal injuries and enhances the application of the scale assessment method in different industrial environments.

Integrated Physiological, Biomechanical, and Subjective Responses for the Selection of Assistive Level in Pedelec Cycling.

In recent decade, pedelec has become one of the most popular transportation modes due to its effectiveness in reducing physical effort. The effects of using pedelec as an alternative mode of exercise were explored in previous studies. However, the effects of pedelec parameters were not quantified for the self-selected gear ratio, random riding speed, and varied road slopes, which restricted its application. Hence, this study aimed to evaluate the effects of gear ratio and assistive torque and to determine the optimum riding condition regarding physiological, biomechanical, and subjective responses of the rider. The riding tests consisted of simulated slope (1.0 vs. 2.5% grade), gear ratio (light vs. heavy), and assistive levels (0.5, 1, 1.5, and 2), and the tests were conducted in a randomized order. A total of 19 non-athletes completed the riding tests to evaluate physiological [metabolic equivalent of task (MET), heart rate, and gross efficiency (GE)], biomechanical [muscle activity (expressed as reference voluntary contraction, RVC) and power output], and subjective responses [rating of perceived exertion (RPE) and sense of comfort (SC)]. The test conditions induced moderate to vigorous intensities (3.7-7.4 METs, 58.5-80.3% of maximal heart rate, 11.1-29.5% of RVC rectus femoris activity, and 9.4-14.2 RPEs). The effects of gear ratio and assistive level on the physiological responses were significant. Riding with the heavy gear ratio showed advantages in METs and GE. For the optimum assistive level selection, low GE and limited improvement in subjective responses suggested the impact of low-power output conditions. Overall, for the health pedelec commuters, riding with 0.75 W/kg power output with 50 rpm cadence is recommended to obtain the moderate intensity (4.7 METs) and the advantages in GE and subjective feelings. Moreover, the findings can be applied to exercise intensity control and save battery energy effectively in varying riding conditions.

FBXO7 triggers caspase 8-mediated proteolysis of the transcription factor FOXO4 and exacerbates neuronal cytotoxicity.

Parkinson's disease (PD) is characterized by the progressive loss of midbrain dopamine neurons in the substantia nigra. Mutations in the F-box only protein 7 gene (Fbxo7) have been reported to cause an autosomal recessive form of early-onset familial PD. FBXO7 is a part of the SKP1-Cullin1-F-box (SCF) E3 ubiquitin ligase complex, which mediates ubiquitination of numerous substrates. FBXO7 also regulates mitophagy, cell growth, and proteasome activity. A member of the FOXO family, the transcription factor FOXO4, is also known to modulate several cellular responses, including cell cycle progression and apoptosis; however, the relationship between FBXO7 and FOXO4 has not been investigated. In this study, we determined that FBXO7 binds to FOXO4 and negatively regulates intracellular FOXO4 levels. Interestingly, we also found that FBXO7-mediated degradation of FOXO4 did not occur through either of two major proteolysis systems, the ubiquitin-proteasome system or the lysosome-autophagy pathway, although it was blocked by a caspase 8-specific inhibitor and caspase 8-knockdown. Moreover, intracellular FOXO4 levels were greatly reduced in dopaminergic MN9D cells following treatment with neurotoxic 6-hydroxydopamine (6-OHDA), which was produced upon FBXO7-mediated and caspase 8-mediated proteolysis. Taken together, these results suggest that FOXO4 is negatively regulated in FBXO7-linked PD through caspase 8 activation, suppressing the cytoprotective effect of FOXO4 during 6-OHDA-induced neuronal cell death.

High prevalence nasal carriage of methicillin-resistant Staphylococcus aureus among long term care facility healthcare workers in relation to patient contact.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health concern worldwide. Healthcare workers (HCWs) are an important source of transmission of MRSA. We conducted a prospective study to define the frequency of S. aureus nasal colonization with emphasis on the carriage of MRSA in HCWs in relation to the intensity of patient contact. METHODS: Out-of-hospital care emergency medical technicians and students, and HCWs in the emergency department, intensive care unit and a long-term care facility (LTCF) were enrolled to compare the prevalence of MRSA and methicillin-susceptible S. aureus (MSSA) nasal colonization. The MRSA isolates were further identified by their microbiological and molecular characteristics. FINDINGS: S. aureus was isolated from 63 of 248 HCWs (25.4%). The overall MRSA nasal carriage rate was 15/248, 6%, and the prevalence was higher in the HCWs who had worked for 5-10 years (12.8%), and among female HCWs (10.3%) than male HCWs (0.9%). LTCFs had the highest prevalence (12%). In contrast, the overall carriage of MSSA was 48/248, 19.4%, and most carriers worked for ≥5 years (52.1%). Hospital nurses had the highest rate of MSSA carriage (21.4%). Most of the MRSA isolates were SCCmec IV/ST59 or ST45 (60%), and were resistant to erythromycin and clindamycin (53%). CONCLUSIONS: Hospital nurses have highest S. aureus nasal carriage, whereas HCWs in the LTCFs comprise a significant reservoir of MRSA colonization. The differences in the characteristics of MRSA and MSSA nasal carriage among HCWs highlights the importance on long-term nasal screening of S. aureus in healthcare facilities.