Belgin Gülhan

Background/Objectives: Hand, foot and mouth disease (HFMD) has recently emerged as a serious health threat, as certain serotypes can cause severe illness. Serotype distribution vary by region, and seroprevalence studies helps in developing preventive strategies. This study aimed to determine the seroprevalence of enterovirus type 71 (EV-A71), Coxsackievirus A16 (CV-A16), Coxsackievirus A10 (CV-A10), and Coxsackievirus A6 (CV-A6), the main causative agents of HFMD and to investigate risk factors for seropositivity. Methods: This multicenter, cross-sectional study was conducted across five major cities in Türkiye. Children (6 months–17 years) who presented to outpatient clinics for any reason were included between May 2024 and January 2025. Neutralizing antibodies were measured using a microneutralization assay. Statistical analyses included descriptive methods, appropriate group comparisons (Chi-square/Fisher’s Exact), and backward logistic regression to identify factors associated with HFMD seropositivity. Results: The study included 998 participants (mean age: 8.6 ± 5.2 years; 51.3% male). CV-A6 antibodies were detected in 68.5%, EV-A71 in 66.5%, CV-A10 in 60.2%, and CV-A16 in 46.0% of samples. No viral antibodies were detected in 5.3% of serum samples (All-Negative group); antibodies against at least one HFMD agent were detected in 94.7% (Any-Positive group). HFMD seropositivity increased significantly with age. Handwashing habits did not differ between the groups. The any-positive group more often had a household member aged 12–18 years, a mother with lower education, and higher kindergarten attendance. In logistic regression analysis, age, average monthly household income, and mother’s education level were the factors influencing seropositivity. Conclusions: The seroprevalence of HFMD-causing viruses in Türkiye is high from six months of age onward. Beyond promoting personal protective measures, the implementation of a vaccination program should also be considered.

The diagnosis of Clostridioides difficile infection (CDI) in children is challenging due to high rates of asymptomatic colonization and the limited ability of available assays to differentiate colonization from true infection. The relative utility of polymerase chain reaction (PCR) versus stool toxin A/B detection by enzyme immunoassay (EIA) remains uncertain in pediatric practice. This study aimed to evaluate whether stool toxin A/B detection adds incremental clinical value among children with gastrointestinal multiplex PCR positivity for C. difficile toxin genes (tcdA/tcdB) by comparing risk factors, treatment decisions, and outcomes according to toxin status. This retrospective observational study included 103 pediatric patients (< 18 years) with PCR positive for C. difficile toxin genes (tcdA/tcdB) results at a tertiary children’s hospital between October 2022 and April 2025. Patients were categorized into three groups: stool toxin A/B not evaluated, stool toxin A/B negative, and stool toxin A/B positive. Demographics, risk factors, clinical characteristics, laboratory findings, treatment decisions, and outcomes were compared across stool toxin A/B groups. Of the 103 patients, 26 (25.2%) had no stool toxin A/B, 63 (61.2%) were stool toxin A/B negative, and 14 (13.6%) were stool toxin A/B positive. More than half of the cohort (54.3%) received CDI treatment, with no significant difference in treatment initiation rates among stool toxin A/B groups. The risk factors—including underlying disease (e.g., malignancies, inflammatory bowel disease, and immunodeficiencies), recent hospitalization, antibiotic exposure, and proton pump inhibitor (PPI) or enteral tube use—were similarly distributed. Clinical severity, laboratory parameters, imaging findings, recurrence, complications (1.0%), ICU admission (4.9%), and mortality (3.9%) did not differ significantly between stool toxin A/B positive and negative patients. Although a statistically significant difference in diarrhea severity was observed across groups, this was driven by the toxin-not-evaluated group. Importantly, stool toxin A/B positivity did not correlate with clinical severity, underlying risk factors, laboratory abnormalities, or outcomes. Conclusion: In this pediatric cohort, stool toxin A/B detection did not provide additional clinical value beyond PCR positivity for C. difficile toxin genes (tcdA/tcdB). PCR alone, when interpreted in the context of compatible symptoms and epidemiological risk factors, may be sufficient to guide treatment decisions for suspected pediatric CDI. Given the limited incremental value of stool toxin A/B testing, optimized diagnostic algorithms and further multicenter pediatric studies are warranted. What is Known: • Pediatric CDI diagnosis is complicated by high asymptomatic colonization; PCR for C. difficile toxin genes (tcdA/tcdB) is sensitive but cannot distinguish colonization from infection. • Stool toxin A/B EIAs are more specific but less sensitive, and guidelines often recommend multistep algorithms. What is New: • In our cohort of pediatric patients with PCR positivity for C. difficile toxin genes (tcdA/tcdB), stool toxin A/B status was not associated with clinical severity, risk factors, laboratory findings, outcomes, or treatment initiation. • When clinical features are compatible, PCR positivity for C. difficile toxin genes (tcdA/tcdB) alone may be sufficient to guide treatment, with limited incremental value of stool toxin A/B testing.

Objective: Data on pediatric residents’ awareness and knowledge of childhood tuberculosis in Türkiye are limited. This study aimed to evaluate the awareness and knowledge levels of pediatric residents regarding childhood tuberculosis at Ankara City Hospital. Materials and Methods: This cross-sectional study was conducted between August and September 2023 among pediatric residents at Ankara Bilkent City Hospital. A 15-item online multiple-choice questionnaire assessed knowledge related to epidemiology and prevention, clinical–laboratory–imaging evaluation, treatment, and prophylaxis of childhood tuberculosis. Incomplete or unsubmitted questionnaires were excluded from the analysis. Results: A total of 172 pediatric residents participated in the study, of whom 72.7% were female. Eighty-six residents (50.0%) were classified as junior and 86 (50.0%) as senior. Senior residents demonstrated significantly higher correct response rates than junior residents regarding incorrect statements about BCG vaccination (53.5% vs. 38.4%, p=0.047), definition of close contact in tuberculosis (91.9% vs. 79.1% p=0.017), interpretation of abnormal PPD values (93.0% vs. 76.7%, p=0.003), microbiological diagnostic methods (80.2% vs. 58.1%, p=0.002), and typical radiographic findings in childhood pulmonary tuberculosis (89.5% vs. 74.4%, p=0.010) (p<0.050 for all). Correct response rates increased progressively with advancing residency year (X2 : 37.295, df:1, p<0.001). Conclusion: Senior pediatric residents demonstrated significantly higher knowledge levels regarding childhood tuberculosis compared with junior residents. These findings highlight the importance of structured and continuous educational programs beginning early in residency and reinforced throughout training. Given the endemic nature of tuberculosis in Türkiye, targeted and regularly updated educational interventions may improve early recognition, diagnostic accuracy, appropriate treatment, and overall clinical outcomes. Future multicenter studies incorporating key domains of tuberculosis knowledge—epidemiology and prevention, clinical–laboratory–imaging evaluation, and treatment and prophylaxis—may help identify regional gaps and guide standardized educational strategies.