Prosthetic devices

Implanted prosthetic devices e.g. pacemaker wires, vascular grafts and heart valves may become infected and when removed may be sent for culture.

Prosthetic devices are occasionally contaminated with normal skin flora and other bacteria when implanted. These bacteria colonize the surface forming a biofilm producing localized infection and may lead to significant infections such as bacteremia and septic thrombosis.

Setup If there is a liquid or tissue component to the sample that can be removed from the device by swabbing or scraping, process as for other tissue specimens. See Tissue.

If not, simply pour thioglycocate broth (THIO) over the specimen in the container it was submitted in.

Interpretation Examine the THIO daily for evidence of growth. If growth in THIO, perform Gram stain and subculture THIO onto BA, MAC, CHOC and WC (plus additional media as appropriate) and incubate in CO2 and anaerobically for the WC.

Any growth of S. aureus, α-haemolytic streptococci, Streptococcus anginosus group, Pseudomonas spp., other Gram negative bacilli and yeasts are significant and worked up.

Other organisms are only to be worked up only if there are <3 different bacterial types. If 3 or more types, descriptively list them without definitive identification or susceptibility testing. Consult with charge technologist or microbiologist if in doubt.

Reporting

Negative Report

“No growth” or “No significant growth including (list of non-significant organisms)”

Positive Report

Report all significant isolates with appropriate susceptibilities.

References H.D. Isenberg. 2004. Specimen Collection, Transport and Acceptability p. 2.1.1 – 2.1.28. In Clinical Microbiology Procedures handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C

H.D. Isenberg, 2004. Wound Cultures – Wound and Soft Tissue Cultures, p. 3.13.1.1 – 3.13.1.16. In Clinical Microbiology Procedures Handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C.

H.D. Isenberg. 2004. Microbiological Assay of Environmental and Medical-Device Surfaces p.13.10.1 – 13.10.12 In Clinical Microbiology Procedures Handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C.

H.D. Isenberg. 2004. Culture of Intravascular Devices p.13.12.1 – 13.12.6 In Clinical Microbiology Procedures Handbook, 2nd Edition, Vol 1 ASM Press, Washington, D.C.