K. kingae ousts S. aureus as top cause of acute septic arthritis in children

The most common cause of acute septic arthritis (SA) is Kingella kingae, confirms a study, noting a small trend as well for decreasing antibiotic duration. In addition, older children with high inflammatory parameters appear to be at greater risk of sequalae.

Children aged <18 years with SA admitted to a tertiary care paediatric hospital from 2003 to 2018, in two cohorts, before and after the implementation of nucleic acid amplification assays (2014) were included in this longitudinal observational, single-centre study. The authors obtained clinical, treatment, and disease progression data.

Two hundred forty-seven children (median age 2 years, 57.9 percent males) were identified, with an average annual incidence of 24.9/100,000. The last 5 years saw a 1.7-fold rise in the annual incidence, a lower median age at diagnosis, and a 49-percent improvement in microbiologic yield.

The most frequent causative organism was K. kingae (51.9 percent), followed by methicillin-susceptible Staphylococcus aureus (19.2 percent) and Streptococcus pyogenes (9.6 percent).

Children were more often treated for fewer intravenous days (10.7 vs 13.2 days; p=0.01). However, complications were more common (20.6 percent vs 11.4 percent; p=0.049), with a similar sequalae rate (3.7 percent). C-reactive protein (CRP) ≥80 mg/L and S. aureus infection correlated with an increased risk for complications; for sequelae at 6 months, the risk factors were age ≥4 years and CRP ≥80 mg/L.

“Acute SA still remains a challenge with significant worldwide morbidity. In recent years, K. kingae has emerged and treatment regimens have become shorter,” the authors said.