UNASSIGNED Human coronavirus NL63 (HCoV-NL63) primarily infects the upper respiratory tract. However, it may cause severe lower respiratory tract infection, and the clinical course may be severe in immunocompromised patients. To our knowledge, child death due to HCoV-NL63 has not been reported. We present a fatal lower respiratory tract disease associated with HCoV-NL63 in a 7-month-old malnourished infant.

Objectives: Septic arthritis (SA) is a serious bacterial infection that must be treated efficiently and timely. The large number of culture-negative cases makes local epidemiological data important. Accordingly, this study aimed to evaluate the etiology, clinical characteristics, and therapeutic approach of SA in children in Turkiye, emphasizing the role of real-time polymerase chain reaction (PCR) techniques in the diagnosis. Methods: In this multi-center, prospective study, children hospitalized due to SA between February 2018 and July 2020 in 23 hospitals in 14 cities in Turkiye were included. Clinical, demographic, laboratory, and radiological findings were assessed, and real-time PCR was performed using synovial fluid samples. Results: Seventy-five children aged between 3 and 204 months diagnosed with acute SA were enrolled. Joint pain was the main complaint at admission, and the most commonly involved joints were the knees in 58 patients (77.4%). The combination of synovial fluid culture and real-time PCR detected causative bacteria in 33 patients (44%). In 14 (18.7%) patients, the etiological agent was demonstrated using only PCR. The most commonly isolated etiologic agent was Staphylococcus aureus, which was detected in 22 (29.3%) patients, while Streptococcus pyogenes was found in 4 (5.3%) patients and Kingella kingae in 3 (4%) patients. Streptococcus pyogenes and Kingella kingae were detected using only PCR. Most patients (81.3%) received combination therapy with multiple agents, and the most commonly used combination was glycopeptides plus third-generation cephalosporin. Conclusions: Staphylococcus aureus is the main pathogen in pediatric SA, and with the use of advanced diagnostic approaches, such as real-time PCR, the chance of diagnosis increases, especially in cases due to Kingella kingae and Streptococcus pyogenes.

Background and Objectives: The mechanisms underlying pneumonia-associated complications are not yet fully understood. Emerging evidence indicates that Sestrin2 (SESN2), a component of the antioxidant defense system, may play a significant clinical role in various diseases. However, the relationship between Sestrin2 expression and pneumonia in pediatric patients is unclear. Materials and Methods: In this study, the relationship between Sestrin2 expression and pneumonia was investigated in children hospitalized for pneumonia between 1 January and 1 April 2024. Results: The study involved 39 patients with a median age of 48 months (range: 12–84) diagnosed with pneumonia and treated at our hospital’s pediatric wards, as well as 37 healthy controls with a median age of 86 months (range: 48–132). In the patient group, the level of reactive oxygen species (ROS) was higher than that in the control group, but the difference was non-significant (394.35 [322.61–586.14] vs. 380.99 [320.03–410.54], p = 0.057). Conversely, the SESN2 level was significantly lower in the patient group than in the control group (2.89 [1.94–4.1] vs. 3.58 [2.94–4.38], p = 0.039). Correlation analysis indicated a strong positive correlation between SESN2 and ROS in the patient group (r = 0.743, p = 0.001), along with a moderate negative correlation between SESN2 and age (r = −0.467, p = 0.003). Conclusions: The decreased SESN2 levels, as observed in the patient group, may contribute to the clinical manifestations of the disease. Mitigating oxidative stress, blocking the elevated ROS levels, and increasing SESN2 levels may be an important step in reducing pneumonia-related complications. For this purpose, SESN2 can be used as a clinical biomarker and prognostic factor in pediatric pneumonia.