Bone and joint infections

Septic arthritis of a native joint

• Joint aspirate in universal container (white) for microscopy and culture
• Joint aspirate in blood culture bottles  - recovery of some organisms may be improved
• Blood cultures if sepsis criteria are fulfilled
• Tissue or pus from formal debridement in universal container (white) for microscopy and culture

Microscopy is not available out-of-hours, any samples received overnight will be processed the next morning.

Prosthetic joints should only be aspirated under sterile theatre conditions, and never on a ward.

Suspected prosthetic joint infection

• Blood cultures if sepsis criteria are fulfilled
• Swabs (black) from any overlying wounds
• Joint aspirate (theatre only) in universal container (white) for microscopy and culture
• Joint aspirate (theatre only) in blood culture bottles - recovery of some organisms may be improved
• Tissue or pus x 3 from formal debridement in universal containers (white) for microscopy and culture
• Swabs (black) are a less useful sample with a poorer diagnostic yield compared to tissue or pus in a universal container

Osteomyelitis

• Blood cultures if sepsis criteria are fulfilled or debridement is not planned in the near future
• Swabs (black) from any overlying chronic ulcers after cleaning of the ulcer surface with tap or sterile water
• Bone samples in universal container (white) obtained at debridement
• Swabs (black) are a less useful sample with a poorer diagnostic yield compared to tissue or pus in a universal container

Do not swab the debris at the ulcer surface, always clean surface first

Suspected discitis

• Blood cultures – sample as if for infective endocarditis
• Biopsy material from affected disc space in universal container

Given the duration of treatment for discitis, culture-based treatment is the gold standard.

Some form of sampling must take place before antimicrobials are started.

Blood cultures can be useful surrogate samples, as direct biopsy of the affected disc space is often not possible or only possible after significant delay.