Improved detection of infection in hip replacements: A currently underestimated problem

Abstract

Our aim was to determine if the detection rate of infection of total hip replacements could be improved by examining the removed prostheses. Immediate transfer of prostheses to an anaerobic atmosphere, followed by mild ultrasonication to dislodge adherent bacteria, resulted in the culture of quantifiable numbers of bacteria, from 26 of the 120 implants examined. The same bacterial species were cultured by routine microbiological techniques from only five corresponding tissue samples. Tissue removed from 18 of the culture-positive implants was suitable for quantitative tissue pathology and inflammatory cells were present in all samples. Furthermore, inflammatory cells were present in 87% of tissue samples taken from patients whose implants were culture-negative. This suggests that these implants may have been infected by bacteria which were not isolated by the techniques of culture used. The increased detection of bacteria from prostheses by culture has improved postoperative antibiotic therapy and should reduce the need for further revision.

Improved Detection of Biofilm-formative Bacteria by Vortexing and Sonication: A Pilot Study

“…For example, Oga et al [9,10] used a rinse method with saline, whereas Olson et al [11] used vortexing for 1 minute without sonication. Moreover, sonication with or without vortexing has been used widely [14,16]. The differences in methods to dislodge biofilms make direct comparisons difficult.…”

“…The sensitivity of diagnostic assays has been improved by the use of techniques that dislodge adherent bacteria from the biofilm [13]. Sonication and/or vortexing increases the number of bacteria isolated from retrieved joint implants [8,14,16]. Trampuz et al [14] reported culture of samples obtained by sonication of explanted hip and knee prostheses was approximately 18% more sensitive than conventional culture of periprosthetic tissue among patients undergoing hip or knee revision or resection arthroplasty and was 30% more sensitive in patients who had received antibiotics within 14 days before surgery.…”

Requirement for TLR9 in the Immunomodulatory Activity of Propionibacterium acnes

“…In this case, mutations in tlr9 resulting in suppression or enhancement of P. acnes reactivity may impair natural resistance to infections and tumor development or may lower the threshold of incidence of oral and bowel inflammatory diseases, respectively. P. acnes is associated with various human pathologies, such as acne vulgaris (53), endophtalmitis (54), endocarditis (55), osteomyelitis (56), sarcoidosis (57), and prosthetic hip infections (58), often together with other bacteria. The identification of TLR9 as an essential factor of P. acnes-induced hypersensitivity to TLR4-and TLR2-dependent microbial components demonstrates that the signaling events through one TLR can lead to a drastic enhancement of the degree of responsiveness of other TLRs.…”

Adhesion of Staphylococcus to orthopaedic metals, an in vivo study

“…Biofilms were analysed by sonication at 50 Hz for 7 min, log reduction and subsequent Columbia blood agar plating, as described by Tunney et al [21]. Results were expressed in colony-forming units adhering to implants per cm squared.…”