Bamrasnaradura Infectious Diseases Institute

Objectives: Overuse of antibiotics is one of the drivers of antimicrobial resistance, especially in acute respiratory tract infection. We examined factors associated with antibiotic prescription among patients treated at two Thai hospitals during 2018-2022. Methods: Medical records of patients with respiratory illness were reviewed to abstract demographics, clinical features, diagnostics, treatments, and outcomes. Factors associated with antibiotic prescribing were assessed. Inappropriate use was defined as antibiotic receipt without laboratory-confirmed bacterial infection, severe symptoms, or clinically suspected bacterial pneumonia. Results: Among 905 inpatients and 1811 outpatients, 46.7% and 31.9% received antibiotics, of which 7.8% and 45.1% were inappropriate, respectively. In-hospital antibiotic use was stable in 2018-2020 (59.0-64.0%) before declining sharply in 2022 (22.7%). Outpatient antibiotic use was stable in 2018-2019 (36.3-29.0%), increased in 2020-2021 (41.8-41.7%), and declined in 2022 (11.5%). Patients aged >65 years (adjusted relative risk [aRR] 1.30); males (aRR 1.11); and those with unstable vital signs (aRR 1.18), ancillary testing (aRR 1.37), hospitalization (aRR 1.23), or bacterial infection (aRR 1.71) had higher odds of receiving antibiotics. Children aged 1 year (aRR 0.81), those with a positive rapid influenza diagnostic test (aRR 0.32), and those treated at a study hospital (aRR 0.83) were less likely to receive antibiotics. Antiviral treatment was associated with lower antibiotic use in 2021-2022 (aRR 0.44 and 0.19) but not in 2019-2020. Conclusion: Antibiotic use among patients with respiratory illness was common, although nearly half of outpatient prescriptions were inappropriate. A positive result from rapid influenza diagnostic test was associated with reduced antibiotic prescribing.

Scrub typhus (ST), caused by Orientia tsutsugamushi, is an underdiagnosed cause of acute febrile illness in Southeast Asia. Acute febrile illness surveillance data from febrile patients presenting to health facilities in two Thailand border provinces (Tak [north] and Nakhon Phanom [northeast]) were analyzed to estimate ST prevalence and describe clinical and epidemiological characteristics and risk factors. Scrub typhus cases were classified as confirmed (polymerase chain reaction-positive), probable (acute-to-convalescent rise in ELISA IgM/IgG plus ≥2 clinical features), or suspect (positive acute and convalescent sera results for anti-IgM/IgG or for patients with only one sera sample, positive acute or convalescent sera results for anti-IgM/IgG and ≥2 of these clinical features). All others were considered non-cases. The 75 ST cases were classified as confirmed (39) or probable (36). Scrub typhus prevalence was higher in Tak (6.9%; 95% CI: 4.8-9.4) than in Nakhon Phanom (1.3%, 95% CI: 0.6-2.3). Common symptoms included headache, fatigue, myalgia, and chills. Discharge diagnosis matched ST case designation 15% of the time. Approximately one-quarter (n = 18) of patients were coinfected with another bacterium (15, 20%) or virus (3, 4%). Appropriate antibiotics were administered to 56% (n = 9) of the 21% (n = 16) of patients who received antibiotics before study specimen collections. Participants in Tak were 4.2 (95% CI: 2.2-8.2) or 4.5 (95% CI: 2.4-8.5) times as likely to test positive for ST if they visited the forest or contacted farm animals, respectively, within the past 30 days. Findings confirm the persistent burden of ST along Thailand's borders. Targeted actions are needed to strengthen clinical management, access to diagnostics, and community-based prevention.

Background:HIV-associated tuberculosis is a leading cause of mortality. Mycobacterium tuberculosis bloodstream infection (MTB-BSI) is complicated by diagnostic difficulty and severe illness. We assessed whether MTB-BSI continues to be common in the era of widespread antiretroviral therapy and whether it continues to result in increased risk of early mortality. Methods:We enrolled inpatients from medical wards irrespective of tuberculosis symptoms and outpatients with tuberculosis symptoms. All participants had HIV and were ≥18 years old, and all were recruited from 7 countries: Malawi, South Africa, Tanzania, Thailand, Uganda, Vietnam, and Zambia. Participants also had <3 doses of antituberculosis treatment in the past 60 days and no isoniazid preventive therapy in the past 6 months. We estimated the prevalence of MTB-BSI. In Bayesian survival models, we estimated the hazards of mortality for inpatients with MTB-BSI vs those without. Results:Between 2019 and 2021, 1703 participants were included: 44% were hospitalized, the median CD4 count was 361 cells/μL, and 77% reported using antiretroviral therapy. Crude prevalence of MTB-BSI varied by country but was 4.4% (32/723) among all inpatients, 22.5% (32/142) among inpatients with microbiologically confirmed TB, and 0.2% (2/913) among all outpatients. Among all inpatients, those with MTB-BSI had 2.65-times (95% credible interval, 1.06-5.01) increased hazard of death by 30 days and 1.79-times (95% credible interval, .81-3.11) increased hazard by 70 days. Lower CD4 and older age were strongly associated with mortality. Conclusions:MTB-BSI is far more common for inpatients than outpatients with HIV. Across multiple settings with high tuberculosis prevalence, MTB-BSI was strongly associated with heightened risk of early mortality in PWH. Novel optimized diagnostic and treatment strategies are still needed for HIV-associated MTB-BSI.

Introduction: Dengue, chikungunya, and hand, foot, and mouth disease (HFMD) are priority notifiable infections in Thailand. Whether vector-borne and contact-mediated diseases responded differently to the coronavirus disease 2019 pandemic has not been quantified within a unified national surveillance framework over an extended period. Methods: We conducted an ecological interrupted time-series analysis using weekly province-level notifiable disease surveillance data from epidemiological week 1 of 2016 to week 53 of 2025 across all 77 Thai provinces. Incidence per 100,000 population was calculated using year-specific civil registration population denominators. Segmented quasi-Poisson regression with two Fourier harmonics for annual seasonality was fitted, with the primary pandemic onset defined as week 1 of 2020 and two alternative onset definitions prespecified for sensitivity analysis. Results: The analysis included 40,579 province-week observations across 527 epidemiological weeks, comprising 790,263 dengue, 32,265 chikungunya, and 713,822 HFMD cases nationally. Immediate incidence rate ratios at pandemic onset were 0.39, 0.54, and 0.51 for dengue, chikungunya, and HFMD, respectively. Sustained post-onset trends diverged across diseases, with declining trajectories for the two vector-borne infections and a positive post-onset slope for hand, foot, and mouth disease. Dengue rebounded above pre-pandemic levels by 2023, chikungunya remained quiescent through 2025, and HFMD exceeded its pre-pandemic baseline by approximately 26%. Conclusion: Vector-borne and contact-mediated diseases in Thailand followed sharply contrasting decadal trajectories that tracked the transmission ecologies of each pathogen. These findings support transmission-mode-specific pandemic-resilient surveillance, accelerated arboviral and enteroviral vaccine deployment, and integrated vector management. ### Competing Interest Statement The authors have declared no competing interest. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was reviewed by the Institutional Review Board of Bamrasnaradura Infectious Diseases Institute (BIDI) and was determined to meet criteria for exemption from full ethical review as minimal-risk secondary research using aggregated surveillance data (IRB Reference: S002h/69_Exempt). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The aggregated province-level weekly surveillance dataset underlying this study has been publicly deposited in Zenodo under the TRENDS Dataset (2016-2025) repository. The dataset contains de-identified, aggregated surveillance records for dengue, chikungunya, and hand, foot and mouth disease, together with accompanying metadata and documentation to support reproducibility and reuse. No individual-level data are included.

Background Urinary tract infection (UTI) is a common complication among hospitalized patients with hip fractures. Several risk factors may increase the likelihood of UTI in this population and can lead to serious complications. This cross-sectional study aims to determine the prevalence of UTI and identify associated risk factors among hospitalized hip fracture patients at a tertiary public hospital in Thailand. Methods We conducted a retrospective cross-sectional study of 140 hospitalized patients with hip fractures from April 2016 to March 2025 and analyzed the prevalence of UTIs and associated risk factors. Logistic regression analysis was used to assess the odds ratio (OR) and 95% confidence intervals (CI). Results UTI occurred in 51 participants (36.4%) of hospitalized hip fracture patients. The mean age in the UTI group was 81.4 years, and UTI was more common in females. Female sex (OR 5.109; 95% CI 1.164 - 22.426), the Osteoporosis Self-Assessment Tool for Asians (OSTA) index ≤ -6 (OR 5.798; 95% CI 1.343 - 25.032), and the estimated glomerular filtration rate (eGFR) stage ≥ 2 (OR 8.946; 95% CI 1.477 - 54.178) were significant risk factors. Conclusion UTI was common among hospitalized hip fracture patients. Female sex, OSTA ≤ -6, and eGFR stage ≥ 2 were the main associated risk factors.