# Clinical characteristics of children with septic arthritis caused by different pathogenic bacteria

## TL;DR

This study examines how different bacteria cause septic arthritis in children, finding that Staphylococcus aureus is most common, while Streptococcus pneumoniae affects younger children.

## Contribution

The study identifies distinct clinical patterns and age distributions for septic arthritis caused by specific bacterial pathogens in children.

## Key findings

- Staphylococcus aureus was the most frequently detected pathogen (67.5%).
- Streptococcus pneumoniae infections occurred more commonly in infants.
- Streptococcus pyogenes was associated with higher white blood cell counts and procalcitonin levels.

## Abstract

Septic arthritis is a serious infectious disease in children. In this study, we retrospectively analyzed the relationship between demographics, laboratory values at presentation, reported symptoms at presentation, joint involvement, and distribution characteristics of pathogenic bacteria in 171 patients during the period of 2012–2022. The results showed that a total of 77 pathogen‐positive patients were detected in the 171 patients (culture‐positive rate of 45.0%), 15 categories of pathogenic bacteria, and the highest detection rates were 52 cases of Staphylococcus aureus (67.5%), Streptococcus pyogenes in 7 cases (9.1%), and Streptococcus pneumoniae in 5 cases (6.5%). Comparison of these three pathogens revealed that the age of the Staphylococcus aureus and Streptococcus pyogenes groups was significantly older than that of the Streptococcus pneumoniae group (p < 0.05), and that the white blood cell count (WBC) of the Streptococcus pyogenes group was significantly higher than that of the Staphylococcus aureus group (p < 0.05), and that the Streptococcus pyogenes group had a significantly higher procalcitonin (PCT), which was significantly higher in the Streptococcus pneumoniae group (p < 0.05). The results suggest that the pathogenic bacteria of septic arthritis in children are mainly Staphylococcus aureus, Streptococcus pneumoniae infection occurred more commonly in the infant stage, and Staphylococcus aureus and Streptococcus pyogenes were detected frequently in school‐age children. Streptococcus pyogenes was found to be more pathogenic than Staphylococcus aureus and Streptococcus pneumoniae.

Children with septic arthritis infected by Streptococcus
pneumoniae were younger than those by Staphylococcus aureus and Streptococcus
pyogenes, and patients with Streptococcus
pyogenes had the highest WBCs and PCTs, The children in the Streptococcus pneumoniae group had a significantly longer time until presentation than those in the Streptococcus pyogenes group, with statistically significant differences.