Bone Infection:

Osteomyelitis is a severe infection of the bone, commonly caused by bacteria such as Staphylococcus aureus. The infection can reach a bone through the bloodstream, from an adjacent infected tissue or through direct contamination from an injury or surgical procedure.

A significant impact of osteomyelitis on human health is its potential to lead to chronic complications, including bone necrosis and impaired growth in children. Treatment typically involves a combination of surgery to remove the infected tissue and long-term antibiotic therapy to eradicate the infection. Early diagnosis and management are crucial to prevent severe outcomes such as bone death or the spread of infection to other parts of the body. ²

Joint Infection

Septic arthritis, also known as infectious arthritis, is an infection that typically affects native joints, most commonly the knee, hip, or shoulder. Stéphanie Pascual, Global Medical Scientist at bioMérieux explains, “This serious condition often arises when pathogens travel through the bloodstream from another area of the body. It can also develop following an infection in a penetrating injury, open wound, or surgical procedure.” Research indicates that septic arthritis leads to severe illness in at least one-third of affected individuals, and the mortality rate for those hospitalized with the condition ranges between 7% and 15%.​³

Prosthetic joint infections are a notably difficult complication related to joint arthroplasty surgery. The management of a prosthetic joint infection is complex and expensive, requiring, in most cases, revision surgery and long-term use of antibiotics, and is associated with significant morbidity and mortality. A recent study found that Multidrug-resistant Gram-negative bacteria were responsible for a substantial proportion of hip prosthetic joint infections, complicating the choice of effective antibiotics.⁴

With both osteomyelitis and septic arthritis, infection can reach the bone or joint in multiple ways and have serious impacts on patient care including prolonged hospitalizations, chronic pain, wounds with discharge, sepsis, permanent disability, even amputation and death.⁵

However, BJIs remain difficult to diagnose due to their complex nature and the limitations with testing methods. According to Pascual, “Definitively identifying a causative organism through is crucial but with conventional methods often unsuccessful, as culture positivity rates are very low.” In the case of prosthetic joint infections, the diagnostic process often involves evaluating multiple factors, including inflammatory markers, synovial fluid analysis, and tissue cultures. No single test provides conclusive results, necessitating a comprehensive approach to increase diagnostic accuracy.

BJIs are therefore challenging to treat effectively until the correct organism has been identified, and they can remain challenging throughout treatment. The avascular nature of bone tissue can limit the penetration of prescribed antibiotics, making it difficult to achieve therapeutic concentrations at the site of infection. There is also the presence of biofilms which could further complicate a treatment plan since bacteria within biofilms exhibit increased resistance to antibiotics.⁶

An analysis utilizing the 2019 Global Burden of Disease Study (GBD) found that disability-adjusted life years (DALYs) attributed to BJIs associated with AMR have been on the rise since 1990. ⁷

Right test. Right Patient. Right Time. Right Interpretation. This is the hallmark of diagnostic stewardship and the path forward in supporting clinicians in the optimal treatment of BJIs.

Rapid and accurate diagnostic tools are crucial in combatting antibiotic overuse, which may result from symptomatology-based prescribing and/or lack of diagnostic certainty.  The introduction of molecular diagnostics has enhanced the ability to identify specific pathogens and detect antimicrobial resistance genes more accurately in BJIs.⁸  “Advanced diagnostic techniques, such as polymerase chain reaction (PCR) and next-generation sequencing (NGS), can enhance pathogen detection and identification. These methods offer higher sensitivity and specificity compared to traditional culture techniques,” Pascual said.

Pascual et al. recently published an article in the Journal of Bone and Joint Infection, evaluating the performance of a multiplex-PCR assay for diagnosing septic arthritis and prosthetic joint infections. The study reported high overall agreement between the JI Panel and synovial fluid cultures for both septic arthritis (88.4%) and prosthetic joint infections (85.7%), with the JI Panel detecting more positive specimens. “This innovative diagnostic tool detected a broader range of pathogens, including difficult-to-culture organisms like Kingella kingae and Neisseria gonorrhoeae—while providing results in approximately one hour. The turnaround time and high diagnostic accuracy suggest potential for improved diagnostic yield and targeted treatment decisions,” says Pascual.

The rise of AMR has added to the difficulty in managing BJIs, necessitating advancements in molecular diagnostics and therapeutic strategies. Through continued research and interdisciplinary collaboration, the medical community can better address the challenges posed by chronic BJIs and the threat of AMR.