Abstract
Aim
We reviewed a cohort of individuals with recurrent orthopaedic infection to describe the relative rates of microbial persistence vs re-infection at recurrence surgery.
Method
A cohort of 125 individuals with recurrent infection (prosthetic joint infection, fracture-related infection and osteomyelitis) from two centres in the UK between 2007 and 2021. Electronic patient records were reviewed to identify culture results from surgical samples at index surgery and the next operation for recurrent infection. Antibiotic sensitivity results were recorded as sensitive, intermediate or resistant according to contemporary sensitivity testing guidelines.
Results
Among patients with recurrent infection, 78/125 (62.4%) were male, with a median age 64 years (IQR 51–73y). 76 had prosthetic joint infection, and 49 had fracture related infection or osteomyelitis. Culture results at index procedure showed the most frequently isolated species were Staphylococci (Table 1). A single species was isolated in 75/125 (60%) and mixed species in 36/125 (28.8%). No organisms were cultured in 14/125 (11.2%).
At re-operation 48/125 (38.4%) individuals had an organism from the same species or group as at the index operation. In 49/125 (39.2%), none of the organisms isolated at re-operation were grown at first operation. In 28/125 (22.4%), re-operative cultures yielded no growth.
For each species isolated at the index procedure, the proportion with the same, different or no organisms isolated at the next procedure were reviewed (Table 1). Staphylococci (including S. aureus and coagulase-negative staphylococci) and Pseudomonas species showed the highest rate of persistence at the species level. Among coagulase-negative staphylococci, changes in antimicrobial sensitivity that make it unclear if these infections were truly persistent, or represented re-infection.
Conclusions
Infection with different organisms was seen at similar rates (39.2% vs 38.4%) to persistent infection with the same species in this cohort. Staphylococcus aureus is the organism most likely to be persistently identified in recurrent infections.
