Aetiology of native joint septic arthritis

In adults, native joint septic arthritis is most commonly caused by Staphylococcus aureus (including methicillin-resistant strains); Streptococcus species are less commonly implicated. Neisseria gonorrhoeae is a common cause in sexually active adults.

In children aged between 4 months and 4 years, Kingella kingae is the most common cause of septic arthritisKhattak, 2021Wong, 2019. K. kingae is part of the normal pharyngeal flora in young children, and children with K. kingae septic arthritis often have a preceding or concurrent upper respiratory tract illness (eg oral mucosal lesions, otitis media)Al-Qwbani, 2016.

In neonates, septic arthritis may be caused by a broader range of pathogens than in older children, including Streptococcus agalactiae (group B streptococcus), S. aureus and gram-negative organismsSwarup, 2020.

Consider a broader range of pathogens, as well as polymicrobial infection, in patients with septic arthritis contiguous with traumatic wounds or ulceration, particularly in patients with contiguous infection involving joints of the hand or lower limbs.

For empirical regimens, see Approach to managing native joint septic arthritis.