Paediatric septic arthritis in a tertiary setting: a retrospective analysis

Abstract

PURPOSE OF THE STUDY: Acute haematogenous septic arthritis is a relatively common condition in the paediatric population. Although Staphylococcus aureus is implicated as the most common causative agent, changes in resistance and the increasing importance of other pathogens have been reported. The purpose of this study is to establish the spectrum of aetiological organisms with their respective sensitivities, and to use this data to evaluate choices in empiric antimicrobial therapy. DESCRIPTION OF METHODS: A retrospective analysis was performed on patients aged 12 years and younger, admitted for suspected septic arthritis, at a tertiary hospital in South Africa from June 2005 to March 2009. All patients with a clinical diagnosis of septic arthritis were included in this study. SUMMARY OF RESULTS: A total of 44 patients from the age of 2 weeks to 12 years were included. Thirty-nine samples were submitted for microbiological investigation. Thirty of these samples yielded bacterial growth; five of these had two microorganisms. Gram-positive organisms were cultured in 79% of isolates. Staphylococcus aureus was cultured in 66% of all isolates. Only three samples were multi-drug resistant. Gram-negative organisms constituted 17% of isolates. Of note is the isolation of a single isolate of Haemophilus influenzae type B, signifying possible vaccine or vaccination failure. CONCLUSION: Gram-positive organisms, in particular Staphylococcus aureus, are still the most prevalent aetiological agent. The current use of cloxacillin as empiric antibiotic therapy will cover 69% of all isolates in this setting; use of coamoxyclav as empiric therapy will increase cover to 80%. Although this 11% difference is seemingly small, opting for co-amoxyclav may significantly reduce morbidity.