Aims: To describe lung ultrasound (LUS) features of Mycoplasma pneumoniae pneumonia and their distribution in pediatric age, and to correlate imaging findings with clinical and laboratory data. Methods: This is a multicenter, prospective, pilot study that involved three hospitals. In total, 35 patients aged 1 month to 17 years, admitted with a diagnosis of Mycoplasma pneumoniae infection, were enrolled. History, clinical, microbiological, and ultrasound data were collected. The LUS examination was performed at admission, recording the following features: presence of subpleural consolidation, bronchograms, B lines, or pleural effusion, and their characteristics. The scans were performed using a standardized approach, in which a composite score was obtained by summing the scores of the different parameters. Results: Consolidations were seen in 97% of children (mostly located in basal, posterior, and lateral fields), and 65% of patients had multiple ones. Non-perilesional B lines were found in 43% of cases, principally in the posterior and basal fields. Pleural effusion was found in 37% of children. The univariate logistic regression showed a correlation between the age of the patient and large-sized consolidations. Moreover, increased lymphocyte count was associated with a lower risk of large-sized consolidations. Conclusions: LUS is a low-cost, non-invasive tool that can reveal findings suggestive of Mycoplasma pneumoniae infection and help physicians better manage children with lower respiratory tract infections, supporting a more personalized diagnostic and therapeutic approach, including antibiotic selection. These preliminary findings also indicate that a larger, comparative study involving other bacterial and viral etiologic agents is warranted to confirm whether LUS patterns are pathogen-specific and whether they can predict clinical outcomes.

Background: Adenovirus infection in children is frequently accompanied by marked systemic inflammation that may overlap with laboratory features traditionally associated with bacterial infection, potentially contributing to antibiotic prescribing. We aimed to characterize the clinical and inflammatory phenotype of hospitalized pediatric adenovirus infection and to investigate the association between inflammatory markers and antibiotic prescribing. Methods: We conducted a retrospective observational study of 111 consecutive children hospitalized with polymerase chain reaction (PCR)-confirmed adenovirus infection between 10 February 2024 and 31 December 2025. Clinical characteristics were described in a detailed 2025 subcohort (n = 60). The 2025 adenovirus cohort was compared with a contemporaneous cohort of children hospitalized with other PCR-confirmed respiratory viral infections (n = 93) and with a previously published Italian cohort (n = 100). Multivariable logistic regression analyses were performed to identify factors independently associated with overall and parenteral antibiotic therapy. Results: The overall cohort had a median age of 22 months (interquartile range [IQR], 14.0–35.5), a median CRP concentration of 63.0 mg/L (IQR, 32.8–117.4), and an antibiotic prescribing rate of 52.3%. Compared with children hospitalized for other respiratory viral infections, those with adenovirus exhibited significantly higher white blood cell counts, absolute neutrophil counts, and CRP concentrations (all p ≤ 0.006), whereas overall antibiotic prescribing was similar (48.3% vs. 51.6%; p = 0.690). Increasing CRP concentrations were independently associated with antibiotic therapy: for each doubling of CRP + 1, the adjusted odds of receiving any antibiotic increased by 58% (adjusted odds ratio [aOR], 1.58; 95% confidence interval [CI], 1.23–2.03; p < 0.001), whereas the odds of receiving parenteral antibiotic therapy increased by 43% (aOR, 1.43; 95% CI, 1.13–1.82; p = 0.003). After adjustment for CRP concentration, age, and sex, adenovirus detection was associated with lower odds of receiving any antibiotic therapy compared with other respiratory viral infections (aOR, 0.31; 95% CI, 0.13–0.75; p = 0.010), whereas no statistically significant association was observed with parenteral antibiotic therapy. Conclusions: Hospitalized children with adenovirus detection exhibited a pronounced inflammatory response compared with children hospitalized with other respiratory viral infections, despite less frequent oxygen therapy and a shorter median hospital stay. Higher CRP concentrations were associated with increased adjusted odds of antibiotic prescribing, whereas adenovirus detection was associated with lower adjusted odds of receiving any antibiotic therapy. These findings underscore the importance of interpreting inflammatory biomarkers within the broader clinical context and support careful antimicrobial prescribing without compromising vigilance for bacterial infection.