Clinical use
Investigation of tissue and fluids samples for the identification of infection from sites other than prosthetic joints.
Background
A wide range of aspirates, tissue biopsies and pus may be sent for investigation. Investigation may be tailored to the site of the specimen so it is essential that this information is included in the request.
Investigation of fluid samples from sterile sites, e.g., ascitic fluid, peritoneal fluid, synovial fluid, pericardial fluid, amniotic and pleural fluid can detect organisms that may indicate potentially life-threatening infections.
Biopsies may be retrieved from all body sites, allowing investigation of deep-seated infections.
Pus samples may be obtained from incision and drainage of abscesses or deep-seated infections. Abscesses are accumulations of pus in tissue and any organism isolated from them may be of significance. They occur in many parts of the body as superficial infections or as deep-seated infections associated with any internal organ. Swabs of pus are an inferior sample and will not have gram stain performed.
Biliary infection can produce significant morbidity and mortality and the prognosis often depends upon whether biliary tract obstruction is present. Bile is normally sterile; however, colonisation may occur, frequently with a mixture of aerobes and anaerobes originating from the gut. Occasionally instrumentation or stenting may lead to colonisation or infection, which may progress to bacteraemia. Fever, previous endoscopic or percutaneous biliary instrumentation, and bilioenteric anastomosis are significant predictors of a positive bile culture.
Osteomyelitis is a progressive infection which results in inflammation of the bone and causes bone destruction, necrosis and deformation. In children the growing ends of long bones are the most common site of infection whereas in adults it is the spine. Risk factors for adult (haematogenous) osteomyelitis include sickle cell disease, immune deficiencies and intravenous drug use.
Microbiological examination of bone marrow is an invasive technique infrequently performed for the investigation of pyrexia of unknown origin (PUO) and occasionally for other indications. It is sometimes undertaken when other less invasive investigations and diagnostic imaging have failed to determine a cause, or, more frequently, when infection is part of the differential diagnosis in the investigation of haematological abnormalities.
Microbiological examination of bone marrow is an invasive technique infrequently performed for the investigation of pyrexia of unknown origin (PUO) and occasionally for other indications. It is sometimes undertaken when other less invasive investigations and diagnostic imaging have failed to determine a cause, or, more frequently, when infection is part of the differential diagnosis in the investigation of haematological abnormalities.
Patient preparation
Obtain the tissue, fluid or pus using aseptic technique under sterile conditions.
Specimen requirements
White top sterile universal for both biopsy and aspirates.
Samples provided in formalin will not be tested by Microbiology.
If more than one tissue or pus sample is being sent, please clearly label them a, b, c etc. and send a separate request form for each specimen.
Minimum volume
1ml for aspirates
Limitations and restrictions
Send to Microbiology without delay.
For optimum results, samples of tissue should reach Microbiology within 2 hours of collection. Larger pieces of tissue may maintain viability of organisms longer. If delayed transport refrigerate sample. Delays over 48 hours are undesirable.
Where possible, obtain samples prior to administration of antibiotics.
Turnaround time
8 days
Analysing laboratory
Microbiology Lab, James Cook University Hospital, Marton Road, TS4 3BW
Additional information
Additional tests for fungal investigation, PCR or Mycobacteria investigation may be requested. Please include these on the request form and contact the laboratory for further information.
Significant clinical details must be provided, this includes whether the patient is diabetic, any recent foreign travel or immunocompromised status of the patient.
If an urgent gram stain is required, please contact the laboratory prior to sending the sample so this can be performed on receipt.