Jiratchaya Sophonphan

Conventional blood culture is the gold standard for pathogen identification for patients with sepsis, but its lengthy turnaround time—encompassing initial bottle incubation and subsequent phenotypic testing—may delay appropriate therapy. The multiplex PCR-based BIOFIRE Blood Culture Identification 2 (BCID2) panel enables earlier pathogen identification and improves patient outcomes. This study aimed to assess the impact of implementing the BCID2 panel versus conventional culture methods on clinical and microbiological outcomes in hospitalized pediatric patients. This case-control cohort study included 150 retrospective and 150 prospective hospitalized patients with positive blood cultures evaluated via parallel BCID2 and conventional culture. The antibiotic stewardship program (ASP) team provided antimicrobial recommendations based on BCID2 results, with final treatment decisions deferred to the attending physicians. Time to targeted therapy was calculated from the initial antibiotic dose—or blood culture collection if the patient was already on antibiotics—to the start of targeted antimicrobial therapy. The median age in the BCID2 group was significantly higher than the pre-BCID2 group, 2.8 vs 1.7 years, respectively ( P = 0.032). While 18 pathogens among the 150 BCID2 cases (12%) were not identified due to being off-panel targets, BCID2 results prompted antimicrobial modification in 28.8% of the remaining cases (38/132). Median time to targeted therapy was 17.0 hours (IQR 9.6–34.2) with BCID2 group versus 24.2 hours (IQR 16.3–52.2) with conventional culture ( P = 0.014). On multivariable logistic regression analysis, the BCID2 intervention remained an independent and significant predictor of achieving rapid antimicrobial optimization (aOR 2.68; 95% CI 1.17–6.14; P = 0.019). BCID2 implementation paired with an active ASP optimizes antimicrobial use in pediatric bacteremia through accelerated targeted therapy. However, a negative BCID2 result requires nuanced clinical interpretation due to the possible presence of off-panel pathogens or rare genotype–phenotype discrepancies. IMPORTANCE: Bloodstream infection (BSI) remains a leading cause of pediatric morbidity and mortality worldwide. While conventional blood culture is the gold standard, its lengthy turnaround time often delays life-saving therapy. Rapid diagnostic testing (RDT), such as the BIOFIRE Blood Culture Identification 2 (BCID2) panel, is now recommended alongside antimicrobial stewardship programs (ASPs) to optimize clinical management. Our study demonstrates that implementing multiplex PCR-based RDT significantly improves patient outcomes by accelerating the time to targeted therapy. Furthermore, the integration of RDT into an ASP was associated with a significant reduction in both 30-day mortality and hospital length of stay. In conclusion, RDT-guided stewardship serves as both a vital diagnostic tool and a clinical engine that transforms the management of pediatric BSI.

Background: Invasive fungal diseases (IFDs) remain an important cause of morbidity and mortality among immunocompromised children. Changes in diagnostic criteria and increasing use of antifungal prophylaxis may influence the epidemiology and clinical presentation of pediatric IFDs. Longitudinal data from Southeast Asia remain limited. This study aimed to characterize temporal trends, clinical features, and outcomes of pediatric IFDs using the 2020 EORTC/MSGERC criteria. Methods: We retrospectively reviewed children aged 0–15 years diagnosed with IFDs at a tertiary-care hospital in Bangkok, Thailand, from 2014 to 2023. IFD episodes were classified as proven, probable, or possible according to the 2020 EORTC/MSGERC criteria and categorized by causative organism. Temporal trends, clinical characteristics, antifungal prophylaxis exposure, and outcomes were analyzed. Results: Among 156 patients, 171 IFD episodes were identified: invasive aspergillosis (60 episodes), invasive candidiasis (61), Pneumocystis pneumonia (33), cryptococcosis (5), other invasive mold infections (8), and endemic mycoses (4). Invasive aspergillosis and Pneumocystis pneumonia demonstrated greater year-to-year variability with higher case numbers in later years, whereas invasive candidiasis occurred consistently throughout the study. A proportion of IFD episodes occurred despite antifungal prophylaxis, including 23.3% of invasive aspergillosis, 8.2% of invasive candidiasis, and 12.1% of Pneumocystis pneumonia. Hematologic malignancies were the most common underlying conditions among children with invasive aspergillosis(68.3%) and Pneumocystis pneumonia (27.3%). Invasive candidiasis primarily affected infants and young children with chronic conditions, including chronic liver or gastrointestinal disease (25.4%) and congenital heart disease (25.4%), and was strongly associated with central venous catheter use (88.9%). Candida albicans remained the most common pathogen, with overall low antifungal resistance. The clinical manifestations were non-specific and overlapped across pathogens, most commonly presenting with fever and organ-specific symptoms. Ninety-day all-cause mortality was 20.3% for aspergillosis, 24.8% for candidiasis, and 12.9% for Pneumocystis pneumonia. Conclusions: Pediatric IFDs remained associated with substantial mortality despite evolving diagnostic criteria and increasing use of antifungal prophylaxis, underscoring the need for improved diagnostic and preventive strategies.

Objective: To evaluate real‐world outcomes of dolutegravir (DTG)‐based first‐line antiretroviral therapy (ART) among people with HIV in Thailand, where baseline HIV‐1 RNA and resistance testing is not routinely available. Methods: This retrospective cohort study enrolled ART‐naive Thai people with HIV aged ≥15 years who initiated DTG‐based ART between 2020 and 2023 under the national Universal Health Coverage programme. People with HIV with ≥1 post‐baseline HIV viral load (VL) measurement were included. Virological non‐suppression (VNS) was defined as VL ≥1000 copies/mL after ≥6 months of ART. The primary outcome was the proportion achieving virological suppression (VL 3 (aSHR 2.11, 95% CI: 1.36–3.27) and residence in northern (aSHR 1.64, 95% CI: 1.12–2.40) or southern Thailand (aSHR 1.99, 95%: 1.30–3.04). Same‐day/rapid ART initiation, sex and WHO HIV clinical staging were not associated with VNS. Conclusions: Nationwide rollout of DTG‐based ART achieved excellent virological outcomes in Thailand. However, higher VNS risk among adolescents, individuals with advanced HIV disease and those in specific regions underscores the need for targeted interventions to improve treatment equity and long‐term viral suppression.

Background While reductions in methicillin-resistant Staphylococcus aureus (MRSA) infections have been reported, vancomycin prescription rates have remained high. Objectives We aimed to update trends in pediatric prevalence and antibiotic susceptibilities of MRSA infections. Methods We conducted a retrospective study in patients aged S. aureus infections during 2016-2022 at a Thai tertiary-care hospital. MRSA was defined when resistant to cefoxitin or oxacillin MIC of >4 µg/mL. Patients with MRSA infections and their first isolates were classified into HA-MRSA or CA-MRSA based on surveillance definitions. Antibiotic susceptibilities were tested using the VITEK 2XL automated system and disk diffusion. The annual prevalence of MRSA patients was estimated and compared with Chi-Square for trend. Results Among 1,059 children with S. aureus infections, MRSA was identified in 82 patients (7.7%; 95%CI 6.2-9.6), consisting of 65 healthcare-associated MRSA and 17 community-associated MRSA. Our trend in MRSA prevalence has exhibited significantly downward (p =0.003). MRSA isolates were fully susceptible to vancomycin, linezolid, and tigecycline, with high susceptibilities to fosfomycin and fusidic acid (>90%), lower to trimethoprim-sulfamethoxazole (77%) and tetracycline (48%), and the least to clindamycin (18%). Conclusions A declining trend and low prevalence of MRSA infections were observed among pediatric patients, justifying the cautious use of vancomycin as empirical therapy for patients without the risk of MRSA acquisition. MRSA isolates remained highly susceptible to most current antibiotics, which further supports the effectiveness of these treatments against MRSA.

Background: Healthcare-associated infections (HAIs) pose a grave threat to patient safety, morbidity, and mortality, contributing to antimicrobial resistance. Thus, we estimated the point prevalence, risk factors, types, and pathogens of HAIs in hospitalized pediatric patients. Methods: A point prevalence survey (PPS) of HAIs in hospitalized pediatric patients < 18 years old was conducted from March to May 2021. Outcomes, risk factors, and types of HAIs associated with HAIs in 41 hospitals across Thailand were collected. Results: The prevalence of HAIs was 3.9% (95% CI 2.9–5.0%) (56/1443). By ages < 1 month, 1 month–2 years, 2–12 years, and 12–18 years, the prevalence of HAIs was 4.2%, 3.3%, 4.1%, and 3.0%, respectively (p = 0.80). Significant independent risk factors were extended hospital length of stay (LOS) and central venous catheter (CVC) use. Compared to an LOS of 14 days had adjusted odds ratios (aORs) of 2.65 (95% CI 1.05, 6.68), 5.19 (95% CI 2.00, 13.4), and 9.03 (95% CI 3.97, 20.5), respectively. The use of a CVC had an aOR of 2.45 (95% CI 1.06–5.66). Lower respiratory tract infection (LRTI) was the most common HAI type (46.4%: 26/56). The highest prevalence of HAIs was predominantly observed in LRTI diagnoses, with the highest among these in the <1 month age category at 2.3% (17/738). Conclusion: The prevalence of HAIs in hospitalized pediatric patients was 3.9%. Extended LOS and use of CVC were HAI risk factors. A strategy for reducing LOS and reviewing insertion indications or the early planned removal of a CVC was implemented. The surveillance of HAIs stands as a cornerstone and fundamental component of IPC, offering invaluable insights that enhance hospital IPC interventions aimed at preventing HAIs.

Diminished immune response after vaccination occurs in cancer patients. This observational study evaluated the immune response and safety profile after COVID-19 vaccination in radiotherapy patients. The study comprised 53 cancer patients undergoing radiotherapy and voluntarily received the COVID-19 vaccine. The two regimens were homologous ChAdOx1-S recombinant (AstraZeneca, AZ), “AZ-AZ” and heterologous “AZ-mRNA”. The seroconversion rate and anti-RBD immunoglobulin geometric mean titers (GMT) were assessed and compared with healthy controls. Adverse effects were assessed using a questionnaire. The seroconversion rate was 52.4% 1 month after the first dose with GMT 4.3 U/mL (95%CI 1.4–13). Following the second dose, the AZ-AZ group achieved 95% seroconversion rate with GMT = 188.4 U/mL (95%CI 67.1–529), which was significantly lower than the healthy cohort, GMT = 945 U/mL (95%CI 708–1261). Cancer patients in AZ-mRNA group achieved a 100% seroconversion rate with a high GMT = 1400.8 U/mL (95%CI 429.5–4566), which was significantly lower than the healthy cohort, GMT = 5169.9 U/mL (95%CI 3582.2–7461.5). Most adverse effects were mild. Our findings suggest that radiotherapy patients had fair immunogenicity after the first dose, but achieved a high seroconversion rate after the second dose with manageable adverse effects. However, their immunologic response was lower than in healthy individuals, indicating that other preventive strategies are needed.

Primary series vaccination with BNT162b2 followed by a booster 5 months later has been recommended for healthy adolescents. We aimed to describe the immunogenicity in a fractional dose of BNT162b2. Adolescents aged 12–18 years were randomized into six arms for primary series administration: 3wPZ30/30 (reference group), 3wPZ30/20, 3wPZ20/20, 6wPZ30/30, 6wPZ30/20, and 6wPZ20/20 μg. A booster was given at 5 months after the second dose using either 10 or 15 μg of BNT162b2. Immunogenicity following vaccination was determined by IgG against receptor-binding domain (anti-S-RBD IgG; BAU/mL), surrogate virus neutralization test (sVNT; %inhibition) and pseudovirus neutralization (pVNT;ID₅₀) against Omicron. Non-inferiority criteria were defined as a lower boundary of the geometric mean ratio (GMR) being greater than 0.67. From September to October 2021, 118 adolescents with a median age (IQR) of 14.9 years (13.9–16.7) were enrolled. Fourteen days after the primary series, the geometric means (GMs) of anti-S-RBD IgG (BAU/mL) were 3090 (95% CI 2761–3460) in 3wPZ30/30. The GMRs of anti-S-RBD were: 0.80 (95% CI 0.67–0.97) in 3wPZ30/20; 1.00 (95% CI 0.83–1.20) in 3wPZ20/20; 1.37 (95% CI 1.13–1.65) in 6wPZ30/30; 1.24 (95% CI 1.02–1.50) in 6wPZ30/20; and 1.36 (1.13–1.64) in 6wPZ20/20. After a booster dose with 15 μg (n = 24) of BNT162b2, sVNT and pVNT against Omicron variant were 91.6 (95% CI 88.4–94.9) and 331 (95% CI 221–495), respectively. In the group that received 10 μg of BNT162b2 (n = 25), sVNT was 85.6 (95% CI 80.0–91.6) and pVNT was 397 (95% CI 267–590). Healthy adolescents had good immune responses to the fractional dose regimen of BNT162b2 and this may be considered as an alternative option.

To achieve the goal of measles elimination, herd immunity with 95% seroprotection in the community is required. This study aimed to describe the measles seropositivity rate among Thai children and adolescents. A cross-sectional study was conducted among children aged 3–18 years in Bangkok and its suburbs. Measles IgG antibodies were measured using a EUROIMMUN enzyme-linked immunosorbent assay kit. Seropositivity is defined as a measles IgG titer of ≥200 IU/L, due to a correlation with a >85% positive rate with a plaque reduction neutralizing titer of >120. Factors associated with seropositivity were analyzed using logistic regression analysis. From May to July 2020, 570 children with a median (IQR) age of 11.7 (9.4–14.8) years were enrolled. The geometric mean titer (GMT) of anti-measles IgG was 281 IU/L (95% CI; 257–306). The proportion of children with seropositivity was inversely correlated with age; 3–5 years 85.3%, 6–9 years 72.5%, 10–14 years 50.7%, and 15–18 years 56.3%. Adolescents aged 10–18 years had a lower measles seropositivity rate compared with young children; aOR 0.29 (95% CI 0.17–0.48). Only half of the adolescents who received two doses of measles-containing vaccine maintained measles IgG above the seropositive level. A measles booster dose for young adults may be needed to achieve the measles elimination goal.

In the era of globally predominant omicron strains, a COVID-19 booster vaccine is needed. Our study aimed to evaluate the immunogenicity of a half-dose BNT162b2 booster after AZD1222 in healthy adults. A randomized trial of volunteers aged 18–69 years who received two-dose AZD1222 was conducted. The participants were randomized to receive the BNT162b2 vaccine intramuscularly—half (15 µg) vs. standard dose (30 µg). The immunogenicity was evaluated by a surrogate virus neutralization test (sVNT) against omicron variants and anti-spike-receptor-binding-domain IgG (anti-S-RBD IgG). From November–December 2021, 100 adults with a median age of 59.3 years (IQR 33.4–65.5) were enrolled. A booster dose was given at median of 98 days (IQR 92–128) after AZD1222. At day 14, the geometric means (GMs) of anti-S-RBD IgG in half- vs. standard-dose group were 2329.8 vs. 2574.7 BAU/mL, with a geometric mean ratio (GMR) of 0.90 (0.77–1.06). The GMs of sVNT against the omicron variant in the half- and standard-dose groups were 74.4% inhibition (95% CI 68.8–80.5) and 67.3% inhibition (57.9–78.1), respectively, with GMR of 0.95 (0.69–1.30). At day 90, the sVNT indicated 22.3% inhibition (95% CI 14.9–33.4) and 20.4% inhibition (13.1–32.0), respectively, with GMR of 1.09 (0.60–1.98). The fractional low-dose BNT162b2 mRNA booster vaccine provided non-inferior immunogenicity responses. During a shortage of vaccine supply, a fractional low dose should be considered for a booster vaccination program.

Adolescents with underlying diseases are at risk of severe COVID-19. The immune response of BNT162b2 may be poor among immunocompromised adolescents. We aim to describe immunogenicity of mRNA BNT162b2 among adolescents who are immunocompromised or have chronic diseases. We recruited adolescents 12–18 years of age; group A impaired-immunity (post-transplantation, cancer, on immunosuppressive drugs) and group B chronic diseases. A two-dose regimen of BNT162b2 was given. Immunogenicity was determined by surrogate virus neutralization test (sVNT) and IgG against receptor-binding domain (RBD). From August to October 2021, 312 adolescents, with a median age (IQR) of 15 years (13.7–16.5), were enrolled (group A 100, group B 212). The geometric means (GMs) of sVNT (% inhibition) against Delta strain and anti-RBD IgG (BAU/mL) after the 2nd dose among group A were: post-transplantation recipients 52.9 (95% CI 37.7–74.2) and 233.6 (95% CI 79–690.6); adolescents with cancer 62.3 (95% CI 29.2–133.1) and 214.9(95% CI 34.2–1348.6); and adolescents with other immunosuppressive conditions 66.7 (95% CI 52.4–84.8) and 849.8 (95% CI 393.4–1835.8). In group B were: adolescents living with HIV 98 (95% CI 97.3–98.8) and 3240.3 (95% CI 2699–3890.2), and adolescents with other chronic disease 98.6 (95% CI 98.3–98.9) and 3818.5 (95% CI 3490.4–4177.4). At day 90, immunity declined; among impaired-immunity participants were 43.9 (95% CI 30.8–62.4) and 178.7 (95% CI 91.2–350.1) and adolescents with chronic diseases were 90.6 (95% CI 88.4–92.8) and 1037.1 (95% CI 933.3–1152.5). In conclusion, adolescents with impaired immunity had a poor response to 2-doses of BNT162b2, additional dose should be considered. Adolescents with chronic diseases had excellent response but immunity waned after 3 m, booster dose may be required.