Chulalongkorn Medical Journal

Antibiotic resistance genes in diabetic foot ulcer microbiomes: Molecular mechanisms and clinical management strategies

2026-08-31T14:21:16+07:00

Background: Diabetic foot ulcers (DFUs) affect 19.0%–34.0% of patients with diabetes during their lifetime, representing a major global health burden with more than 18 million cases annually. The polymicrobial nature of DFU infections, combined with emerging antibiotic resistance genes, poses considerable clinical management challenges. Methicillin-resistant Staphylococcus aureus (MRSA) prevalence reached 84.0% and extended-spectrum beta-lactamase (ESBL) production exceeded 50.0% among gram-negative isolates in some regions, creating urgent therapeutic concerns.

Objectives: This comprehensive review examines the current understanding of microbial communities in DFUs and their associated resistome, analyzes the molecular mechanisms underlying antibiotic resistance, and evaluates the clinical implications to identify evidence-based management strategies.

Methods: A narrative review was conducted using systematic searches of PubMed/MEDLINE, Embase, Web of Science, and Google Scholar from 2014 to 2025. Search strategies utilized MeSH terms, including “diabetic foot ulcer,” “antibiotic resistance genes,” “microbiome,” and “resistome.”

Result(s): Analysis revealed extensive resistome diversity, with individual ulcers harboring dozens of distinct resistance determinants. The predominant resistance genes included mecA (methicillin resistance, 48.7%– 84.0%), blaCTX-M, blaSHV, blaTEM (ESBL production, 26.7%–64.7%), and various fluoroquinolone resistance genes (qnrS, 15.4%). Horizontal gene transfer mechanisms facilitate the rapid dissemination of resistance within polymicrobial biofilm communities, thereby substantially affecting treatment outcomes and increasing treatment failure rates.

Conclusion: Antibiotic resistance in DFUs poses a critical challenge that requires urgent, multifaceted approaches. Future directions should prioritize rapid diagnostic technologies, precision antimicrobial approaches, and innovative therapeutic interventions, including antimicrobial photodynamic therapy and bacteriophage treatment, to address this growing threat.

Role of perceived control over falls in older adults

2026-07-31T14:34:57+07:00

Falls among older adults constitute a considerable public health challenge, often leading to severe physical injuries, reduced independence, and a diminished quality of life. Perceived control, a critical psychological construct, plays a substantial role in sustaining physical health, cognitive function, and overall life satisfaction, and it is strongly associated with positive health outcomes. This review aims to examine the role of perceived control in fall risk among older adults. Concern about falling (CaF) is a prevalent psychological factor that influences fall risk by affecting behaviors linked to physical activity, balance, and adaptive responses. Perceived control theory provides a framework for understanding how older adults’ confidence in managing falls shapes their emotional responses and behavioral adaptations, thereby influencing fall-related outcomes and overall health. This review highlights the complex and multidimensional nature of perceived control related to falls. High levels of perceived control are positively correlated with better physical and mental health, whereas lower perceived control is associated with an increased fall risk and compromised well-being. A thorough analysis of theoretical models and empirical studies highlights perceived control as a mediator that promotes adaptive behaviors, supports emotional resilience, and encourages proactive engagement in fall prevention strategies. By identifying knowledge gaps in the existing literature, this review encourages further research on factors that influence perceived control and the development of standardized assessment tools that address the psychological and physical aspects of fall prevention. Such tools could enhance the independence and well-being of older adults.

Pre-excited atrial fibrillation in a woman with minimal pre-excitation: A case report

2026-07-10T10:30:41+07:00

A 46-year-old Thai woman presented with palpitations. A 12-lead electrocardiogram (ECG) showed rapid preexcited atrial fibrillation (AF). The ECG following electrical cardioversion demonstrated minimal pre-excitation with a short PR interval and small apparent delta waves only in leads II, III, V4, and V5. An electrophysiologic study was performed and revealed sinus rhythm with a short H-V interval compatible with pre-excitation. A programmed electrical stimulation revealed orthodromic atrioventricular re-entrant tachycardia via the left lateral accessory pathway. Catheter ablation was successfully performed using a retrograde aortic approach to the left lateral accessory pathway. There was no recurrence of Wolff–Parkinson–White ECG pattern, supraventricular tachycardia, or AF during the 12-month follow-up visit. This is a rare case of minimal preexcitation presenting with pre-excited AF as the first presentation. This case report reflects that minimal preexcitation does not indicate a low risk of ventricular fibrillation and sudden cardiac arrest.

Incidental leftward displacement of the appendix due to redundant sigmoid colon: A case report of anatomical variation

2026-06-17T09:07:20+07:00

A left-sided appendix is an uncommon clinical finding, often attributed to congenital anomalies, such as situs inversus or intestinal malrotation. However, it can also arise from anatomical displacement by other organs, such as redundant colonic loops. While rare, such variations may complicate the clinical and radiological diagnosis of abdominal pain and result in potentially serious consequences if not recognized. This case report highlights a left-sided appendix due to a redundant sigmoid colon incidentally discovered during the evaluation of right lower quadrant pain. A 22-year-old woman presented to the emergency department with right flank pain, which later localized to the right lower quadrant (RLQ). There was localized tenderness in the RLQ, with no systemic symptoms. A working diagnosis of acute appendicitis was considered. A noncontrast abdominal computed tomography scan revealed a 0.4 cm right lower pole nephrolithiasis without signs of appendiceal inflammation. Unexpectedly, the appendix was visualized at the mid-left lower quadrant due to displacement by a type C redundant sigmoid colon. The patient was referred to urology for further management. This report highlights the importance of recognizing anatomical variations. They may substantially alter the expected location of intra-abdominal organs and result in diagnostic confusion. Although the patient in this report did not have appendicitis, the displacement of the appendix into the left lower quadrant could have been misleading had inflammation occurred. Radiologists and clinicians should both be cognizant of atypical disease presentations, and accurate diagnosis and treatment are crucial for an optimal outcome, especially in emergency settings.

Acute treatment response among patients with migraine subtypes: A real-world study in Thailand

2026-09-09T13:22:10+07:00

Background: Migraines with and without aura may have distinct etiologies. Aura can vary in complexity (from simple to complex), which potentially reflects differences in cortical involvement and influences acute treatment response.

Objective: To compare the acute treatment responses between patients with migraine with and without aura, as well as aura complexity levels, in Thailand.

Methods: A retrospective cohort study was conducted from January 3, 2007, to June 30, 2022, at the Chulalongkorn Comprehensive Headache Center, King Chulalongkorn Memorial Hospital, Thai Red Cross Society. Baseline data were retrieved from the baseline case-record forms, while clinical data were obtained from paper headache diaries and follow-up case-record forms. The primary outcome was a 2 h pain-free response; secondary outcomes included pain scores and associated symptoms.

Results: Among the 358 patients (110 with aura, 248 without), baseline characteristics were largely similar, except for differences in the associated symptoms (photophobia and phonophobia) and the use of antiepileptic drugs for migraine prevention. No significant differences in acute treatment response were found between the groups. However, patients with complex auras exhibited a trend toward better outcomes, with higher 2 h pain-free rates (44.5% vs. 23.9%) and greater improvement in pain duration (33.3% vs. 22.8%) compared with patients with simple auras.

Conclusion: Acute treatment responses did not differ significantly across migraine types, although patients with complex aura may respond better.

Assessing the responses of miRNA-200b and miRNA-429 in cyanide poisoning cases

2026-09-01T14:22:13+07:00

Background: Cyanide toxicity disrupts cellular respiration by inhibiting mitochondrial cytochrome oxidase a3, resulting in cellular hypoxia. The cell’s response to hypoxia is mediated by hypoxia-inducible factors (HIFs) and associated microRNAs (hypoxamiRs). Among these, miR-429 and miR-200b have been implicated in the regulation of HIFs and were found to be upregulated during acute hypoxic conditions. However, their specific roles in cyanide-induced hypoxia remain poorly understood.

Objective: The aim of this study was to evaluate the expression of miR-429 and miR-200b in postmortem peripheral blood collected from cyanide poisoning fatalities.

Methods: Postmortem blood was obtained from five cyanide poisoning cases and five nonasphyxial controls; for all cases, the postmortem interval was < 24 hours. After total RNA was extracted from the blood, 10 ng of RNA was reverse-transcribed into complementary DNA using MultiScribe™ Reverse Transcriptase. The expression of miR-429 and miR-200b was quantified using the QuantStudio™ 5 system and TaqMan™ MicroRNA assays. Relative miRNA expression was calculated using the 2 ΔΔCTmethod and compared using the Mann–Whitney U test. One cyanide case was excluded because of low RNA quality.

Results: Toxicological screening confirmed lethal cyanide concentrations consistent with oral ingestion. Common autopsy findings included pulmonary edema and renal tubular injury, with no definitive cerebral hypoxic changes. The comparative analysis revealed that miR-429 and miR-200b tended to be higher in the cyanide group (n = 4) than in the controls (n = 5), but the differences were not statistically significant (miR- 429: P = 0.31; miR-200b: P= 0.22).

Conclusion: This study identified higher expressions of miR-429 and miR-200b in cyanide poisoning cases compared with controls, which was consistent with previous evidence linking these microRNAs to hypoxic responses. Although the increase in expression did not meet statistical thresholds, the observed patterns indicate that these microRNAs may be involved in cyanide-induced hypoxia. These preliminary findings underscore the need for further investigation of larger, well-defined cohorts to fully elucidate the diagnostic and mechanistic roles of miR-429 and miR-200b in cyanide toxicity.

Epidemiological analysis of scorpion-sting cases in Qeshm County, Hormozgan Province, Iran: A four-year retrospective study (2021–2024)

2026-09-02T10:02:59+07:00

Background: Scorpion stings are a major public health issue in tropical and subtropical regions of Iran, particularly in Hormozgan Province, where the incidence thereof is high.

Objective: This study aimed to analyze the epidemiological, clinical, and therapeutic aspects of scorpionsting cases in Qeshm County over four years (2021–2024).

Methods: A retrospective cross-sectional study analyzed hospital records from 408 scorpion-sting cases. Information on demographic, temporal, geographical, clinical, and treatment factors was collected. Descriptive statistics (frequency, percentage, mean ± standard deviation) and analytical tests (chi-square for categorical variables) were employed for analysis.

Results: The majority of victims were male (63.7% ± 2.4%), aged 30–60 years (41.9%), and residents of rural areas (72.1% ± 2.2%). The highest frequency of stings occurred from late spring to summer (65.4% ± 2.4%) and between 18:00 and 24:00. The extremities, particularly hands (58.8% ± 2.4%) and feet (32.6% ± 2.3%), were the most common sting sites. Hemiscorpius lepturus was the most frequently identified species (37.5% ± 2.4%), whereas the species remained unspecified in 47.1% ± 2.5% of cases. The primary treatment involved the administration of antivenom (96.3% ± 0.9%).

Conclusion: Scorpion stings in Qeshm County demonstrate specific demographic and seasonal trends that align with the broader epidemiological profile in Iran. However, there is a notable challenge in identifying the species involved in these incidents. This highlights the importance of improving diagnostic capabilities for species identification, implementing targeted public health interventions in rural areas, and ensuring a consistent supply of antivenom to address this ongoing health issue.

Association of VEGF gene polymorphisms and breast cancer susceptibility: An updated systematic review and metaanalysis

2026-09-10T10:24:10+07:00

Breast cancer is among the most common malignancies in women worldwide, with genetic predispositions and environmental factors. Low-penetrance genes such as breast cancer (BRCA)1 and BRCA2 have been identified with implications in breast cancer susceptibility. Vascular endothelial growth factor (VEGF) polymorphisms that code for the VEGF protein play an important part in carcinogenesis by modulating angiogenesis required for tumor growth, invasion, and metastasis. There are five polymorphisms associated with the VEGF gene: 936 C > T, 2578 C > A, 634 G > C, 460 T > C, and 405 C > G, which have been linked to altered cancer risk. Despite inconsistencies in many results due to small sample sizes and methodological differences, this study aimed to clarify the associations between VEGF polymorphisms and breast cancer risk by conducting a meta-analysis. A systematic review and meta-analysis were performed and reported in accordance with the PRISMA 2020 guidelines. Twenty-five eligible articles contributed 53 polymorphismspecific case–control datasets that included five VEGF polymorphisms. Statistical analyses were performed using Metagenyo software, and the results revealed a significant association. The 2578 C > A and 460 T > C polymorphisms were associated with increased risks, while 936 C > T and 634 G > C were not. Subgroup analyses also revealed that Asian populations are more susceptible than Caucasians in the overall five polymorphisms. The 405 C > G polymorphism exhibited significance in the dominant and over-dominant models. In the sensitivity analysis, all the effects remained the same except for 405 C > G, which was influenced by a single study. The publication bias was low in all the data. The findings of the present study suggest that VEGF polymorphisms may serve as population-specific genetic biomarkers for breast cancer risk stratification. These variants may also help identify patient subgroups that are more likely to benefit from VEGF-targeted or other anti-angiogenic therapies by influencing VEGF expression and angiogenic activity. However, their clinical utility for treatment selection and prediction of therapeutic response requires validation in larger, ethnically diverse cohorts and in prospective pharmacogenomic studies.

COVID-19 vaccination is associated with lower mortality and intensive care unit admission among hospitalized patients with COVID-19: A retrospective cohort study

2026-08-25T13:19:22+07:00

Background: Vaccination has been central to reducing severe coronavirus disease 2019 (COVID-19). However, the association between prior vaccination and outcomes among patients hospitalized with COVID-19 remains clinically relevant.

Objective: To investigate the association between COVID-19 vaccination status and mortality and intensive care unit (ICU) admission among hospitalized patients with COVID-19.

Methods: This retrospective single-center cohort study included adults hospitalized with reverse transcription polymerase chain reaction -confirmed COVID-19 between July 2021 and February 2022 who had documented vaccination status and underwent at least one chest computed tomography (CT) scan. The exposure of interest was full COVID-19 vaccination. Primary outcomes were mortality and intensive care unit (ICU) admission. Associations were examined using regression models adjusted for age, type 2 diabetes, hypertension, cardiac disease, and pulmonary disease. Exploratory predictor analyses were performed using Least Absolute Shrinkage and Selection Operator (LASSO) regression.

Results: The analytic cohort comprised 167 patients: 69.0% were male, mean age was 58 years (95% CI [55 60]), and 42.0% were fully vaccinated. Full vaccination was associated with lower adjusted relative risk of mortality (RR: 0.46, 95% CI [0.13 0.99]) and ICU admission (RR: 0.59, 95% CI [0.28 0.89]). The adjusted absolute risk difference for ICU admission corresponded to an observational number needed to treat like estimate of four, which should be interpreted cautiously. In patients younger than 60 years, vaccination was associated with fewer ICU admissions (RR: 0.64, 95% CI [0.32 0.99]).

Conclusion: COVID-19 vaccination was associated with lower mortality and reduced ICU admission among hospitalized patients with COVID-19 in this retrospective single-center cohort. Because of the observational design, selected hospitalized CT-imaged population, and potential residual confounding, these findings should be interpreted as associations rather than proof of causal protection.