Analysis of the Stomal Microbiota of a Percutaneous Osseointegrated Prosthesis: A Longitudinal Prospective Cohort Study

Abstract

Percutaneous osseointegrated (OI) prostheses (POPs) are used to skeletally attach artificial limbs in amputees. While any permanent percutaneous interface is at risk of becoming infected by the resident microbiota colonizing the stoma, most of these patients remain infection-free. Avoidance of infection likely depends upon a mechanically and/or biologically stable skin-to-implant interface. The ultimate question remains, "why do some stomata become infected while others do not?" The answer might be found in the dynamic bacterial communities of the patient and within the stomal site itself. This study is an appendix to the first Food and Drug Administration approved prospective early feasibility study of OI prosthetic docking, in which, 10 transfemoral amputees were implanted with a unique POP device. In this analytical, longitudinal cohort study, each patient's skin and stomal microbiota were analyzed from the initial surgery to 1 year following the second-stage surgery. During each follow-up visit, three swab samples-stomal, device thigh skin and contralateral thigh skin-were obtained. DNA was extracted, and bacterial 16S ribosomal RNA (rRNA) genes were amplified and sequenced to profile microbial communities. The stomal microbiota were distinct from the microbiota on the adjacent thigh skin and the skin of the contralateral thigh, with a significantly increased abundance of Staphylococcus aureus within the stoma. Early on stomal microbiota were characterized by high diversity and high relative abundance of obligate anaerobes. Over time, the stomal microbiota shifted and stabilized in communities of lower diversity dominated by Streptococcus, Corynebacterium, and/or Staphylococcus spp.

Achieving stomal continence with an ileal pouch and a percutaneous implant

“…Although this should be regarded as an incomplete structural barrier, the surrounding host defence provides an additional functional barrier in situations with infection and breach of the structural barrier [42,48]. A local, and possible permanent, change in the stomal microbiota following the implantation of percutaneous, bone-anchored prostheses in humans has been demonstrated, both for limb prostheses [19,49] and the BAHS [27,29]. These studies confirmed colonisation by pathogens, typically Staphylococcus spp., at the implant sites, and often, these findings were independent from traditional clinical signs of infection [19,27].…”

A preliminary, observational study using whole-blood RNA sequencing reveals differential expression of inflammatory and bone markers post-implantation of percutaneous osseointegrated prostheses

“…Ten veteran unilateral transfemoral amputees, who were recruited to participate in an FDA-approved Early Feasibility Study of a POP device (NCT02720159), were also included in this current study (NCT02564432) with IRB approval (#00073178). The study design, described in detail previously [ 19 ], is briefly outlined below. A (Level II) prospective, longitudinal, observational study was conducted where participating patients underwent two separate surgical procedures to fit a transfemoral percutaneous OI implant [DJO global, Austin, TX] with a wait time of 6–8 weeks between procedures.…”

Transkutane osseointegrierte Prothesensysteme (TOPS) zur Versorgung Oberschenkelamputierter

“…Dabei ist es jedoch nicht zielführend, auf Bakterienfreiheit zu therapieren. Im Gegenteil ist sogar bekannt, dass der Stomakanal und die Öffnung des Stomas nach der Etablierung des Stomas sofort mit Bakterien besiedelt werden [27] und diese sogar einen protektiven Charakter besitzen können. Baktierennachweise im Stoma sind nicht mit Infektion gleichzusetzen und in gewissem Maße physiologisch [27].…”

“…Im Gegenteil ist sogar bekannt, dass der Stomakanal und die Öffnung des Stomas nach der Etablierung des Stomas sofort mit Bakterien besiedelt werden [27] und diese sogar einen protektiven Charakter besitzen können. Baktierennachweise im Stoma sind nicht mit Infektion gleichzusetzen und in gewissem Maße physiologisch [27]. In einer 12-monatigen Untersuchung der Besiedelungsdynamik an TOPS-Stomata konnte Beck et al feststellen, dass im Vergleich zur umgebenden Haut des Oberschenkels, Staphylococcus aureus (S.aureus) im Stoma signifikant häufiger auftrat [27] obwohl keine Infektion oder Weichteilirritation vorlag.…”

“…Baktierennachweise im Stoma sind nicht mit Infektion gleichzusetzen und in gewissem Maße physiologisch [27]. In einer 12-monatigen Untersuchung der Besiedelungsdynamik an TOPS-Stomata konnte Beck et al feststellen, dass im Vergleich zur umgebenden Haut des Oberschenkels, Staphylococcus aureus (S.aureus) im Stoma signifikant häufiger auftrat [27] obwohl keine Infektion oder Weichteilirritation vorlag. Allerdings kann S. aureus ein opportunistischer, schwer-infektiöser Erreger sein, insbesondere wenn das Immunsystem des Patienten verändert ist oder wenn Eintrittspforten, wie z.…”