Since autumn 2022, observed numbers of paediatric invasive group A Streptococcus infections in Portugal (n = 89) were higher than in pre-COVID-19 seasons. Between September 2022 and May 2023, the dominant diagnoses were pneumonia (25/79), mostly with empyema (20/25), and sepsis (22/79). A number of cases required admission to intensive care (27/79) and surgery (35/79), and the case fatality rate was 5.1% (4/79). Genomic sequencing (n = 55) revealed multiple genetic lineages, dominated by the M1_UK sublineage (26/55) and more diverse emm12 isolates (12/55).

Background: Acute septic arthritis (SA) still remains a challenge with significant worldwide morbidity. In recent years, Kingella kingae has emerged and treatment regimens have become shorter. We aim to analyze trends in SA etiology and management and to identify risk factors for complications. Methods: Longitudinal observational, single center study of children (<18 years old) with SA admitted to a tertiary care pediatric hospital, from 2003 to 2018, in 2 cohorts, before and after implementation of nucleic acid amplification assays (2014). Clinical, treatment and disease progression data were obtained. Results: A total of 247 children were identified, with an average annual incidence of 24.9/100,000, 57.9% males with a median age of 2 (1–6) years. In the last 5 years, a 1.7-fold increase in the annual incidence, a lower median age at diagnosis and an improved microbiologic yield (49%) was noticed. K. kingae became the most frequent bacteria (51.9%) followed by MSSA (19.2%) and S. pyogenes (9.6%). Children were more often treated for fewer intravenous days (10.7 vs. 13.2 days, P = 0.01) but had more complications (20.6% vs. 11.4%, P = 0.049) with a similar sequelae rate (3.7%). Risk factors for complications were C-reactive protein ≥80 mg/L and Staphylococcus aureus infection, and for sequelae at 6 months, age ≥4 years and CRP ≥ 80 mg/L. Conclusions: The present study confirms that K. kingae was the most common causative organism of acute SA. There was a trend, although small, for decreasing antibiotic duration. Older children with high inflammatory parameters might be at higher risk of sequelae.

Linezolid has been used in the treatment of multidrug-resistant/extensively drug-resistant tuberculosis in adults with encouraging results, however experience in children is scarce. We describe our experience with the use of linezolid as part of a multidrug regimen in the treatment of 4 patients who had persistent positive cultures, despite prolonged combined therapy.

Background: Osteoarticular infections (OAI) are associated with complications and sequelae in children, whose prediction are of great importance in improving outcomes. We aimed to design risk prediction models to identify early complications and sequelae in children with OAI. Methods: This observational study included children (>3 months–17 years old) with acute OAI admitted to a tertiary-care pediatric hospital between 2008 and 2018. Clinical treatment, complications and sequelae were recorded. We developed a multivariable logistic predictive model for an acute complicated course (ACC) and another for sequelae. Results: A total of 240 children were identified, 17.5% with ACC and 6.0% and 3.6% with sequelae at 6 and 12 months of follow-up, respectively. In the multivariable logistic predictive model for ACC, predictors were fever at admission [adjusted odds ratio (aOR): 2.98; 95% confidence interval (CI): 1.10–8.12], C-reactive protein ≥100 mg/L (aOR: 2.37; 95% CI: 1.05–5.35), osteomyelitis (aOR: 4.39; 95% CI: 2.04–9.46) and Staphylococcus aureus infection (aOR: 3.50; 95% CI: 1.39–8.77), with an area under the ROC curve of 0.831 (95% CI: 0.767–0.895). For sequelae at 6 months, predictors were age ≥4 years (aOR: 4.08; 95% CI: 1.00–16.53), C-reactive protein ≥110 mg/L (aOR: 4.59; 95% CI: 1.25–16.90), disseminated disease (aOR: 9.21; 95% CI: 1.82–46.73) and bone abscess (OR: 5.46; 95% CI: 1.23–24.21), with an area under the ROC curve of 0.887 (95% CI: 0.815–0.959). Conclusions: In our model we could identify patients at low risk for complications and sequelae, probably requiring a less aggressive approach.

(1) Background: We aim to identify clinical and laboratorial parameters to distinguish Kingella kingae from pyogenic septic arthritis (SA). (2) Methods: A longitudinal, observational, single-centre study of children < 5 years old with microbiological positive SA admitted to a paediatric hospital from 2013–2020 was performed. Clinical and laboratorial data at admission and at 48 h, as well as on treatment and evolution, were obtained. (3) Results: We found a total of 75 children, 44 with K. kingae and 31 with pyogenic infections (mostly MSSA, S. pneumoniae and S. pyogenes). K. kingae affected younger children with low or absent fever, low inflammatory markers and a favourable prognosis. In the univariate analyses, fever, septic look, CRP and ESR at admission and CRP at 48 h were significantly lower in K. kingae SA. In the multivariate analyses, age > 6 months ≤ 2 years, apyrexy and CRP ≤ 100 mg/L were significative, with an overall predictive positive value of 86.5%, and 88.4% for K. kingae. For this model, ROC curves were capable of differentiating (AUC 0.861, 95% CI 0.767–0.955) K. kingae SA from typical pathogens. (4) Conclusions: Age > 6 months ≤ 2 years, apyrexy and PCR ≤ 100 mg/L were the main predictive factors to distinguish K. kingae from pyogenic SA < 5 years. These data need to be validated in a larger study.