In a case of septic arthritis, which of the following organisms is most commonly associated with this condition?

Septic arthritis is most commonly caused by Staphylococcus aureus, which is a type of bacteria that frequently infects joints, especially in both adults and children. This organism is particularly associated with both acute and chronic forms of septic arthritis due to its ability to produce virulence factors that facilitate tissue invasion, as well as its prevalence as a skin commensal that can gain access to the bloodstream and joints through breaks in the skin.

In pediatric patients, Staphylococcus aureus has emerged as the leading cause of septic arthritis, particularly among those who are not vaccinated against strains like Streptococcus pneumoniae or in those with underlying health issues. The organism’s ability to form biofilms and resist certain antibiotics further complicates treatment, making it critical to identify cases early and provide appropriate antibiotic therapy.

Other organisms listed may also cause septic arthritis, but they are less common. For instance, Escherichia coli is typically associated with urinary tract infections and can cause septic arthritis primarily in specific contexts, such as in immunocompromised patients. Haemophilus influenzae was once a common cause of septic arthritis in children before the widespread use of the Hib vaccine, and Streptococcus pneumoniae can cause septic arthritis though it is more often associated with